Funding for vector-borne disease surveillance, management, and research is cyclical and reactive in the United States. The subsequent effects have yielded gross inequities nationally that unintentionally support recurrent outbreaks. This policy forum is comprised of four primary subsections that collectively identify specific areas for improvement and offer innovative solutions to address national inadequacies in vector borne disease policy and infrastructure.

Amblyomma americanum L. is an important vector in North America originally described by Linnaeus based on Pehr Kalm's 1754 report. While Kalm's ‘Travels into North America’ is well known, his 1754 report remains obscure. Some authors were skeptical that Kalm referred to A. americanum because he encountered them at sites farther north outside of the species’ range. However, the details in 1754 report leave no doubt that Kalm described lone star ticks. In this historical review, we provide support for Kalm’s identification using a modern translation of his 1754 report and other sources. We also delineate distributional changes of lone star ticks from the pre-colonization era to the present and interpret them in the context of large-scale anthropogenic changes in the landscape. In this framework, the lone star tick’s current northward expansion is a recolonization of their former range. Extensive deforestation and extirpation of their principal host species, white-tailed deer, led to A. americanum’s disappearance from the northern parts of its range by the 20th century. Subsequent recolonization by second-growth forest and increases in white-tailed deer populations by the mid-20th century is now allowing A. americanum to reclaim its former range.These changes in the land appear to be the driving force behind A. americanum’s present expansion. Understanding this species’ history and the factors contributing to its current expansion will enable better predictions about its future distribution and potential to transmit human pathogens.

Human African trypanosomiasis (HAT), despite considerable progress in the control, is still occurring in many countries in both west and central African regions. The HAT situation in the Republic of Congo has always been overshadowed by its neighbor the Democratic Republic of Congo where over 60% of all HAT cases occur. In the Republic of Congo, HAT cases have been significantly reduced to about 20 reported cases yearly and the disease is still prevalent in few foci across the country. Although continuous assessment of HAT situation in Congo is been led by the National Control Program for HAT, research on the vector, parasite, and vector control has received little attention. Because there have not been enough reviews summarizing key findings from studies conducted so far, there is still a poor understanding of the global situation of HAT in Congo. In order to achieve sustainable elimination of HAT in Congo a deep appraisal of HAT situation is required. The present study provides a review of studies conducted on HAT in the republic of Congo since the 1950s to date in order to identify gaps in knowledge and help consolidate the gains and progress towards the elimination of sleeping sickness.

The use of semiochemicals as repellents and attractants has been proposed to complement insecticides used for the control of vector mosquito populations. In several studies, the optical purities of the molecules tested have been described as having little or no effect on repellent activity. However, these observations seem difficult to explain because of the chirality effect of molecules on the olfactory system of insects and humans. Thus, the purpose of this study is to assess the effects of chirality on the repellent properties of 4-alcoxycoumarins against Aedes albopictus Skuse, mosquito vector of arboviruses. We report here that the racemic (R/S)-4sec-butoxycoumarin had the highest repellent effect (Repellent Index = 49.9%) followed by (R) enantiomer (Repellent Index = 24.2%) for the dose of 5 mg/mL. Contrary, no significant repellent activity was recorded for S-(+)-4-sec-butoxycoumarin. This experiment demonstrates the close relationship between the molecules' optical purities and the behavioral response of mosquitoes.

Aedes aegypti (L.) and Aedes albopictus (Skuse) mosquitoes of both sexes were attracted to a 3-part volatile synthetic phytochemical blend but differed according to their component ratios, 7:3:2 or 1:1:1, and their initial concentrations. These arbovirus vectors were presented with the blends as baits in paired baited and blank CFG traps in a large greenhouse mesocosm. Ae. aegypti attraction was highest at a 7:3:2 blend ratio, but at a concentration half that found most effective for an anopheline mosquito species in outdoor screenhouses. Both lower and higher concentrations yielded substantially lower attraction scores for Ae. aegypti. By contrast, the few tests conducted on Ae. albopictus showed that it was not as sensitive to concentration, but again it was more responsive to the 7:3:2 ratio of components than to the 1:1:1 ratio. The two sexes of both species were represented equally in the trap catches, indicating the potential value of this and similar attractive blends for population surveillance and control of Aedes mosquitoes.

This study registers the diversity of Culicidae in the Bom Retiro Private Natural Heritage Reserve (RPPNBR), Rio de Janeiro state, Brazil, based on the collection of the immature stages in natural and artificial larval habitats. Larvae and pupae were collected monthly at two sites of the RPPNBR from May 2014 to July 2015 using dippers and aquatic pipettes.The diversity of the mosquito community was described using the Shannon–Wiener Diversity Index (H′), as well as diversity, richness, and dominance of species found in different larval habitats (lake, bamboos, bromeliads, and artificial vessels). The Mann–Whitney test was used to calculate differences between the two natural and artificial habitats. Overall, 15,659 specimens belonging to 25 species, ten genera, and two subfamilies were collected.The most abundant species collected at sites that were reforested recently were Culex pleuristriatusTheobald, 1903, Limatus durhamii (Theobald, 1901), Aedes albopictus (Skuse, 1895), Culex neglectus (Lutz, 1904), and Culex retrosus (Lane & Whitman, 1951). In a forest preserved site, the most abundant species were Cx. neglectus, Culex iridescens (Lutz, 1905), Sabethes identicus (Dyar & Knab, 1907), Wyeomyia arthrostigma (Lutz, 1905), and Li. durhamii. With respect to larval habitats, 0.1% of the specimens were collected along the edge of a lake, 5.5% in bamboos, 35.9% in bromeliads, and 58.4% in artificial containers. Only 5.5% of the specimens were collected in the forest preserved site, with the remaining samples from the site with altered vegetation. A greater species richness and diversity were found in forest-altered sites compared to the forest preserved site. Several species were collected in the water accumulated in the nylon lids of plastic water tanks. Such vessels can promote an increase in mosquito population density in the environment surrounding the study area.

Calliphora grahami (Aldrich, 1930) (Diptera: calliphoridae) is a forensically important blow fly that is widely distributed across Asia, North America, Russia, and Mexico. Calliphora grahami is frequently found on corpses during the spring, autumn, and winter seasons. It is among the early colonizers of cadavers during the cold season, and sometimes, the only necrophagous blow fly on cadavers. Therefore, this species is of forensic significance, although very few studies have explored the application of its intrapuparial age for PMI estimation. This study aimed to examine the intrapuparial development of C. grahami and establish a method for estimating its intrapuparial age. Herein, the C. grahami puparia were studied under six different temperatures (13, 16, 19, 22, 25, and 28°C) for the intrapuparial age estimation, and a total of 5776 puparia were sampled. The morphological changes were divided into 11 stages based on the 1) development of legs and wings, 2) differentiation of the head, thorax, and abdomen, 3) growth and color of the bristles, and 4) color changes of the compound eyes. The corresponding time of each stage was determined. Moreover, the observation and classification of individual morphological features, including compound eyes, antennae, mouthparts, thorax, abdomen, legs, and wings was used to improve the precision of intrapuparial age estimation. The findings of this study provide important information on the use of C. grahami intrapuparia to estimate the minimum postmortem interval (PMI_min).

Lhasa is located on the Qinghai–Tibet Plateau, with an altitude of 3,650 m, and a unique geography. Its climate is dry and cold all year round. Forensic entomological studies of the region are scarce. In this study, the diversity and seasonality of necrophagous flies in eight counties among Lhasa region were determined, and succession of necrophagous flies colonizing on rabbits in the Chengguan area of Lhasa was studied, so as to provide reference data for estimating postmortem interval (PMI) and location of death. In total, 22 species of necrophagous flies, belonging to six families were identified in Lhasa. Protophormia terraenovae (Robineau-Desvoidy, 1830) (Diptera: Calliphoridae) was the dominant species throughout the year, the diversity index (4.5834) indicated that the study on necrophagous flies in the Lhasa region is representative.

This is the first study in Brazil that monitored the nocturnal oviposition behavior of Chrysomya putoria, a species of forensic importance, in order to verify if individuals of this species oviposit at night. Groups of 10 flies (5 male and 5 female) distributed in ten cages were kept in a fume hood and submitted to total darkness or exposed to artificial light for eleven consecutive hours through four experimental conditions in the laboratory. Two verifications were made to see if the females oviposited in the offered substrate of about 20 g of chicken gizzard per cage. Verification 1 occurred at 09:00 pm in the evening experiments and at 09:00 am in the daytime experiments. Verification 2 occurred at 05:00 am in the night experiments and at 05:00 pm in the daytime experiments. Each experiment lasted 5 d. C. putoria laid eggs at night (with or without light) and the quantity of eggs was significantly similar to those produced during the day under natural light or in total darkness. Only the amount of eggs produced during the day in the absence of light was considerably greater than in the typical daytime period. The females oviposited in greater quantity in the nights when the average temperature was between 23 and 24.8°C and relative humidity above 81%. Ovipositions only occurred at temperatures above 21°C and humidity above 56% during the day. Finally, it is necessary that more evaluations on the effect of variables on blowfly behavior are performed to better understand nocturnal oviposition.

Flesh flies comprise a large fly family distributed worldwide that has great importance for forensic entomology. A robust and updated checklist of Sarcophaginae flies recorded in Southern Brazil is presented, based on material collected in the Rio Grande do Sul state and on a literature review. The forensic importance (high, moderate, or none) of the recorded flesh flies for estimating the postmortem interval (PMI) or inferring cases of neglect was determined based on their ecological habits. A total of 2,831 specimens representing 38 taxa were collected from three studies. Oxysarcodexia was the most abundant and species-rich genus in all three studies. Dexosarcophaga carvalhoi (Lopes) was registered for the first time in Southern Brazil. The checklist for Southern Brazil comprises 91 species distributed in 19 genera, with Oxysarcodexia, Peckia, and Lepidodexia representing the richest genera. Considering the importance of species for PMI estimation, 10, 42, and 39 species were classified as having high, moderate, or no forensic relevance, respectively. Moreover, five myiasis-causing sarcophagine flies recorded in Southern Brazil were considered to have the potential to reveal cases of neglect or mistreatment. This study revealed that Microcerella halli (Engel) and Peckia (Euboettcheria) australis (Townsend) are the most important species for PMI estimation in Southern Brazil, as they are often found breeding in corpses in this region.

The present study aimed to determine the effects of the soil type and the moisture contents on the some life-history parameters of Lucilia sericata (Meigen, 1826) (Diptera: Calliphoridae). The larval and pupal survival, duration of development periods, and the weight of pupae and adult of L. sericata were examined at three different types of soil (clay, loamy, and sandy) with five moisture contents (0, 25, 50, 75, 100%).The post feeding L. sericata larvae were transferred to a plastic cup filled with soils with different moisture content, and all cups were kept at 27°C, 65% RH, and a photoperiod of 12:12 (L:D) h. In this article, the effects on some life-history parameters were compared with a two-way analysis of variance (ANOVA). Accordingly, the findings of this article indicate that moisture contents of soils and soil type have a significant effect on the development time of L. sericata. Furthermore, it has been found that larvae can survive on extremely wet substrates (75–100% humidity), although their development time is longer than other moisture content. Pupal and adult weight was significantly different among soil type and soil moisture. Our results provide a reference information for sufficient estimation of the effects of changes in moisture-related to soil type or climate on studies of forensic and biological control of L. sericata.

Our knowledge on many necrophilous dipterans was limited for a long time mainly due to taxonomic issues. Therefore, findings on the sex-related associations with pig carcasses in Dryomyzidae, Fanniidae, Muscidae, and Piophilidae are presented. Moreover, the effectiveness of pitfall traps and sweep nets in fly sampling were compared, since the correct method of collecting insects is critical for the development and application of entomological tools for forensic purposes. The trapped numbers of all species differed significantly in respect to both sexes. The sex ratios were strongly female-biased in most species of Muscidae and in Fanniidae. More females were also collected in Piophilidae, but the proportion of males was higher when compared to muscids. Within Dryomyzidae, the sex ratio differed according to species. Only Dryomyza flaveola (Fabricius, 1794) (Diptera: Dryomyzidae) and Muscina pascuorum (Meigen, 1826) (Diptera: Muscidae) had male-biased sex ratios. Differences in residency patterns between sexes in Stearibia nigriceps (Meigen, 1826) (Diptera: Piophilidae), Liopiophila varipes (Meigen, 1830) (Diptera: Piophilidae), and D. flaveola were statistically insignificant. All studied species were recorded for each sampling method. The effect of the sampling method on the number of individuals was statistically significant for all dipterans but Piophilidae. Pitfall traps outcompeted the aerial sweep net in representing Dryomyzidae and Muscidae, whereas both methods were almost equally effective in the collection of Piophilidae. A varied effectiveness of sampling methods was observed in Fanniidae. The sampling method significantly affected the determination of the appearance time of flies on carcasses, but the effect of species and sampling method was insignificant. Implications for forensic entomology are discussed.

In the southern coast of Mar Chiquita Lake, central Argentina, mosquitoes affect public health and community livelihood, since they transmit pathogens to human beings causing diseases such as malaria, filariasis, encephalitis, yellow fever, and dengue, among others, and have a negative effect on cattle farming as well. To characterize the structure of the mosquito assemblage of the region, we determined the species composition and diversity, the temporal distribution of different species, and the patterns of species richness, abundance, and diversity across seasons. We collected adult mosquitoes over a two-year period (October 2004–September 2006) by means of CDC light traps baited with CO₂ from 18:00 to 08:00 h during the warm season (October–April) and from 12:00 h to 18:00 h in the cold season (May–September). A total of 71,501 individuals from 30 species were collected, with Culex Linnaeus and Aedes Meigen genera representing more than 98% of collected specimens (61.5% and 37.3%, respectively). The higher values of richness and abundance of Culicidae were registered in warm seasons compared to cold seasons. Chao1 estimates suggested that more than 90% of the species were detected in all seasons. Mosquito abundance distribution fit the logarithmic series and log-normal models. Aedes albifasciatus (Macquart), Ae. scapularis (Rondani), Culex interfor Dyar, Cx. saltanensis Dyar, and Cx. dolosus (Lynch Arribálzaga), vectors incriminated in arbovirus transmission, were abundant year-round, with Cx. saltanensis and Cx. dolosus most prevalent in cold seasons. Further studies are needed to assess the role of these species in arbovirus transmission in this region of central Argentina.

Species diversity can be affected by the structure of vegetation, which may vary in height, density, and distribution of trees, shrubs, and other plant types, configuring different types of habitats. In this study, we evaluated the diversity of sarcosaprophagous Sarcophagidae communities inhabiting the remnant representative habitats protected in Ciervo de los Pantanos National Park: grasslands, forests, and wetlands. We hypothesized that the abundance and diversity of flesh flies would be higher in the grasslands and wetlands than in the forest patches. Samplings were carried out in each habitat type using baited traps during the four seasons in 2015, 2016, and 2019. We collected 585 sarcophagid flies of 17 species. Fifteen species were recorded in grasslands, twelve in the wetlands, and seven in the forests, Tricharaea (Sarcophagula) occidua (Fabricius) (Diptera: Sarcophagidae) being the most abundant (58.3% of the total sample). As expected, the highest abundance was recorded in grasslands whereas the lowest was found in forests. In addition, flesh fly abundance was affected by season. Sarcophagid assemblages differed between habitats and the overall dissimilarity was mainly explained by nestedness. This study provides important information about sarcosaprophagous sarcophagid flies in a little-studied protected natural area in Argentina, which is fundamental for their conservation and useful in forensic investigations.

Graphical Abstract

Dengue is the leading arboviral infection in the Philippines. Its endemicity in the country is due to the presence of its primary mosquito vector, Aedes aegypti (L.). This species has limited microsatellite markers. This study characterized microsatellite markers screened in silico from intergenic regions of the updated reference genome of Ae. aegypti from Liverpool, U.K. Criteria for good markers are: polymorphic, inherited in a Mendelian codominant manner, no null alleles, selectively neutral, randomly associated, and broadly applicable across different regions. Genotypes were scored using ABI Peak Scanner and were screened for the presence of null alleles. Hardy-Weinberg equilibrium, linkage disequilibrium, and robustness of the markers were determined by GENEPOP using Ae. aegypti samples from selected highland and lowland sites (n = 30 each) in the Philippines and outgroups (Thailand and Vietnam). Mendelian codominant inheritance was examined using F1 offspring of Ae. aegypti family (n = 30 each) derived from samples collected from Cebu city highlands and Maramag, Bukidnon. From the 63 randomly selected markers, nine were polymorphic. Two markers (Aaeg1-3D of chromosome 1 and Aaeg3-4C of chromosome 3) satisfied all criteria, hence, are good broadly useful microsatellite markers. Two other markers (Aaeg2-2E of chromosome 2 and Aaeg3-2A of chromosome 3) met all criteria but deviated from Mendelian codominant inheritance. These new markers of the Philippine Ae. aegypti with their chromosomal locations relative to the other published markers are presented, and will ultimately be useful in a variety of population genetic studies of Ae. aegypti to protect the public health.

The Triatoma sordida subcomplex traditionally included four triatomine species, T. sordida, Triatoma garciabesi, Triatoma guasayana, and Triatoma patagonica, distributed in the Southern Cone of South America. These species have a large intraspecific variability together with an overall similarity, making difficult to establish their taxonomic status. Many cytogenetic, morphometric, and molecular markers have been applied to address this. Recent studies have posed concerns on the inclusion of T. guasayana and T. patagonica within the subcomplex. Also, T. sordida from Argentina has been designed as a new species, Triatoma rosai. Using the cuticular hydrocarbon pattern as chemotaxonomic marker, the relationships among several populations of these species were analyzed by capillary gas chromatography and linear discriminant analysis along 25 collection sites in Argentina, Bolivia, Brazil, and Paraguay. T. sordida and T. rosai populations were differentially clustered in two CHC-based groups: “Group 1” included T. sordida from Eastern Brazil, Eastern Paraguay, and the Bolivian populations from La Paz and Izozog G1; “Group 2” included T. rosai, and T. sordida from Izozog G2 (Bolivia), and Western Paraguay. Whereas T. garciabesi remained closely related to T. sordida and T. rosai, T. guasayana, and T. patagonica were clearly separated from the species of the T. sordida subcomplex. Our results agree with those from other several techniques suggesting that the taxonomy of the T. sordida subcomplex should be revised.

Tick-borne diseases (TBD) in humans have dramatically increased over recent years and although the bulk of cases are attributable to Lyme Disease in the Northeastern US, TBDs like spotted fever rickettsiosis and ehrlichiosis heavily impact other parts of the country, namely the mid-south. Understanding tick and pathogen distributions and prevalence traditionally requires active surveillance, which quickly becomes logistically and financially unrealistic as the geographic area of focus increases. We report on a community science effort to survey ticks across Arkansas to obtain updated data on tick distributions and prevalence of human tick-borne disease-causing pathogens in the most commonly encountered ticks. During a 20-mo period, Arkansans submitted 9,002 ticks from 71 of the 75 counties in the state. Amblyomma americanum was the most common tick species received, accounting for 76% of total tick submissions. Nearly 6,000 samples were screened for spotted fever group Rickettsia (SFGR) and Ehrlichia, resulting in general prevalence rates of 37.4 and 5.1%, respectively. In addition, 145 ticks (2.5%) were infected with both SFGR and Ehrlichia. Arkansas Department of Health reported 2,281 spotted fever and 380 ehrlichiosis cases during the same period as our tick collections. Since known SFGR vectors Dermacentor variabilis and Amblyomma maculatum were not the most common ticks submitted, nor did they have the highest prevalence rates of SFGR, it appears that other tick species play the primary role in infecting humans with SFGR. Our investigation demonstrated the utility of community science to efficiently and economically survey ticks and identify vector-borne disease risk in Arkansas.

Anopheles gambiae sensu lato complex (An. gambiae s.l.) describes a group of nine morphologically indistinguishable members that vary in their distribution, ability to transmit malaria, and susceptibility to pyrethroids. Here, we recorded the spatial patterns of PCR-identified An. gambiae s.l. complex species collected from four sites in Cross River State, Nigeria that represented three different ecological zones. Trapping was conducted between October 2015 and June 2016. Anopheles gambiae s.l. complex species identification was performed using species-specific primers followed by An. gambiae and An. coluzzii differentiation using the restriction fragment length polymorphism (RFLP) method. Bivariate and multivariate logistic regression models were used to identify ecological and seasonal variables closely associated with An. coluzzii and An. gambiae distribution. Out of 1,388 An. gambiae s.l. successfully amplified, 1,074 (77.4%) were An. coluzzii, 278 (20%) were An. gambiae, and 25 (1.8%) were hybrids (An. coluzzii/An. gambiae). A very small number of An. arabiensis (0.8%, n = 11) were also collected. Statistical analysis indicated that An. coluzzii is predominant in Guinea-savannah and tropical rainforest, and is highly associated with rainy seasons, while, An. gambiae is prevalent in mangrove swamp forest during dry seasons. Only 13 An. gambiae s.l. females were infected with Plasmodium falciparum (P. falciparum). The sporozoite infection rate was higher in mangrove swamp forest (53.8%, n = 7) than in rain forest (38.5%, n = 5) followed by Guinea-savannah (7.7%, n = 1) ecological zones. These results provide important insights for strategic planning of malaria control programs in Nigeria.

Control of mosquito vectors of pathogens remains heavily dependent on the application of conventional insecticides. Pyriproxyfen (PPF) is a novel insecticide that has been proposed for use in autodissemination techniques to control mosquito vectors. The use of PPF can inhibit adult emergence but does not inhibit larval development. This feature is favorable for controlling Aedes aegypti because PPF has the potential to work in combination with natural sources of mortality (competition, predation) during the immature stages, and other control methods, including biocontrol agents that further suppress recruitment of adult mosquitoes. However, the PPF effects on life-history traits of Ae. aegypti in comparison to predatory mosquito Toxorhynchites rutilus, a source of mortality, are not fully understood. Here, we show that larval exposure to PPF concentrations that inhibit 50–90% of adult emergence in Ae. aegypti had a negligible effect on adult emergence and lifespan of Tx. rutilus. Weights of adult Ae. aegypti and Tx. rutilus were not influenced by PPF. These findings suggest that the use of PPF to control mosquito vectors may have low effects on mosquito biocontrol agents. Our results extend and confirm earlier data showing that PPF has potential to implement with Tx. rutilus to suppress Ae. aegypti and provide an additional advantage of PPF use in autodissemination control strategies.

Integrated tick management (ITM) is a comprehensive strategy used to reduce presence of ticks and their associated pathogens. Such strategies typically employ a combination of host and non-host targeted treatments which often include fipronil-based, rodent-targeted bait boxes. Bait boxes target small-bodied rodents, specifically white-footed mice (Peromyscus leucopus Rafinesque) that not only play a crucial role in the blacklegged tick (Ixodes scapularis Say (Ixodida: Ixodidae)) life cycle, but also in the transmission of numerous pathogens, primarily Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner (Spirochaetales: Spirochaetaceae), the causal agent of Lyme disease. This study aimed to determine the effect of bait box deployment configuration on tick burden reduction while also further exploring bait consumption and P. leucopus abundances as measures of bait box usage and effectiveness. Boxes were deployed on nine properties within each of six neighborhoods (n = 54) in two different configurations: grid and perimeter. Multiple factors were analyzed as potential predictors for reduction in tick burdens using a backward stepwise selection procedure. Results confirmed the perimeter configuration was a more effective deployment strategy. In addition, overall P. leucopus abundance was a significant predictor of tick burden reduction while bait consumption was not. These findings not only further support the recommended perimeter deployment configuration but provide insight into effective utilization in areas of high P. leucopus abundance. The identification of this significant relationship, in addition to configuration, can be utilized by vector control professionals and homeowners to make informed decisions on bait box placement to make sustained impacts on the I. scapularis vector and associated pathogens within an ITM framework.

The effects of tsetse-transmitted trypanosomosis control in high tsetse flies (Glossina spp.) challenge and trypanocidal drug resistance settings remain poorly understood in Togo owing to poor data coverage on the current disease impact. From March 2014 to November 2017, a database of zoo-sanitary surveys integrating the evolution of disease incidence and intervention coverage made it possible to quantify the apparent effects attributable to the control effort, focused on all sedentary cattle breeds in the 1,000 km² area of Mô inTogo.The strategy involved an initial phase with cross-sectional entomological and parasitological.Then, three times a year, 20% of the bovine animals of the study area received α-cypermethrin pour-on, and infected cattle with poor health (798 cattle in 2014 and 358 in 2017) were individually given diminazene aceturate at 7 mg/kg of body weight.The tsetse density in the area decreased significantly, from 1.78 ± 0.37 in March 2014 before the α-cypermethrin application to 0.48 ± 0.07 in February 2017. The α-cypermethrin pour-on application and diminazene aceturate treatment of cattle led to the largest reduction in disease incidence, from 28.1% in 2014 to 7.8% in 2017, an improvement in hematocrit from 24.27 ± 4.9% to 27.5 ± 4.6%, and a reduction in calf mortality from 15.9 ± 11% to 5.9%. Improved access to these interventions for different types of livestock and maintaining their effectiveness, despite high tsetse (Diptera: Glossinidae) challenges, should be the primary focus of control strategies in many areas of Togo.

Graphical Abstract

Although malaria is endemic in some areas of southeastern Iran, following the successful national malaria elimination plan, the local transmission area has been shrunk. The main cases in Iran are due to Plasmodium vivax followed by P. falciparum. This study was aimed to determine the current situation of malaria in Kerman Province of Iran and evaluate the insecticide resistance of main vectors. The field study was conducted in 2019. Data of new malaria cases were obtained from the health centers for the period of 2009–2018. Susceptibility status of Anopheles stephensi and An. dthali was evaluated against dichlorodiphenyltrichloroethane, Dieldrin, Malathion, Bendiocarb, Deltamethrin, and Temephos at the diagnostic dose. A total of 522 malaria cases were recorded and divided into indigenous (33.14%) and imported (66.86%) categories. The highest incidence of the disease was reported from the southern areas of the province, where all indigenous cases occurred. Adults of An. stephensi were resistant to dichlorodiphenyltrichloroethane while its resistance to be confirmed to dieldrin, bendiocarb and deltamethrin. As An. dthali had less than 98% mortality against bendiocarb, the resistance status should be confirmed with more tests. Our findings showed both species had less than 98% mortality against bendiocarb and deltamethrin insecticides which are used in malaria vector control program in Iran. Due to the susceptibility of these vectors to temephos, larviciding can be advised for vector control in this area.

Long lasting permethrin-impregnated (LLPI) clothing can retain permethrin and repel ticks for up to three months and without exceeding EPA-approved safe levels; however, little is known about longer term effects of wearing LLPI clothing. Here, permethrin content was measured in new forester pants soon after initial impregnation (Insect Shield) and again one year later after being repeatedly worn by foresters in the field. Urine samples were collected from foresters for biomonitoring of permethrin metabolites at multiple time intervals (pre-use, one-month, three-to-four-months, and one-year post-use). Lethality against nymphal Ixodes scapularis Say was measured in clothing after one year of wear by foresters. Furthermore, to test potential variability in permethrin impregnation of different batches of clothing, separate sets of clothing were anonymously sent to Insect Shield for permethrin treatment over a period of three months and permethrin was quantified. Results demonstrated 33% of participants' pants had no measurable permethrin after one year of wear and permethrin content and tick mortality varied significantly between clothing. Only two of the participants' clothing resulted in ≥ 30% tick mortality after one year of wear. Significant differences were observed in 3-PBA and trans-DCCA, but not cis-DCCA metabolites in participants over the four measured time points and were higher than general United States population levels. This study provides practical information on the safety (measured by urinary metabolites) over time of LLPI clothing. It also provides snapshots (pre-washing and after one year of wear) of effectiveness of LLPI clothing as personal protective equipment against ticks for outdoor workers.

Sugar is an essential source of nutrition for adult mosquitoes to acquire energy. Toxic sugar bait (TSB) provides a promising method for mosquito control by incorporating toxins into artificial sources of sugar (i.e., toxic baits) presented to wild populations. Spinosyns comprise a family of bacterial secondary metabolites with a unique mode of action against the insect nervous system, an appealing environmental safety profile, and potential for incorporation into sugar baits.This research evaluated acute and subacute effects of spinosad (spinosyns A and D) and spinetoram (spinosyns J and L) in sugar meals on survival, fecundity, and fertility of Aedes aegypti and Aedes albopictus. Acute toxicity of spinosyns doubled from 24 to 48 h of assessment, revealing a relatively slow and cumulative action of the formulated spinosyns. Median lethal concentrations at 48 h were lower for spinetoram than for spinosad, lower for Ae. albopictus than Ae. aegypti, and lower for males than females. When exposed to subacute LC₅₀ concentrations of spinosad and spinetoram for 24 h, survival of males and females of both species was diminished compared with controls, fecundity of females was increased, but fertility as measured by hatch rate of eggs was decreased. The formulations may have increased the nutritive value of the sugar meals thereby boosting fecundity, while toxifying embryos, reducing fertility. The inclusion of subacute effects of spinosyns allows assessment of the broader consequences of TSB for adult mosquito control.

High abundance of hematophagous mosquitoes of the genus Mansonia Blanchard, 1901 (Diptera: Culicidae) threatens human and domestic animal health and well-being. Knowledge of the biology of nuisance mosquito species is necessary to understand specific ecological and biological factors to enable rapid and effective monitoring measures for sustainable control programs. The establishment and dispersion of Mansonia species are associated with the occurrence of aquatic macrophytes species, which are indispensable for the development of larvae and pupae. To increase knowledge of the host plants for Mansonia immature stages in Porto Velho, Rondonia State, Brazil, specimens of four plant species, which occur across the tributaries of the Madeira River were sampled and inspected for the presence of egg batches, larvae, and pupae. A total of 1,386 larvae and pupae of Mansonia spp. were collected attached to the roots of Eichhornia crassipes (Mart.) Solms (Commelinales: Pontederiaceae), Pistia stratiotes L. (Alismatales: Araceae), and Limnobium laevigatum (Humb. and Bonpl. Ex Willd.) Heine (Alismatales: Hydrocharitaceae). The novel association of Mansonia species with L. laevigatum is presented. Egg batches of Mansonia spp. were found only on Salvinia molesta D.S. Mitch. (Salviniales: Salviniaceae). Possible differences in the roles played by E. crassipes and S. molesta in the reproductive cycle of Mansonia spp. in the surveyed area are discussed. All species of host plants including E. crassipes, P. stratiotes, S. molesta, and L. laevigatum should be considered when planning macrophyte management for the control of Mansonia species.

Piperonyl butoxide (PBO)-synergized pyrethroid products are widely available for the control of pyrethroid-resistant mosquitoes. To date, no study has examined mosquito resistance after pre-exposure to PBO and subsequent enzymatic activity when exposed to PBO-synergized insecticides. We used Culex quinquefasciatus Say (Diptera: Culicidae), an important vector of arboviruses and lymphatic filariasis, as a model to examine the insecticide resistance mechanisms of mosquitoes to PBO-synergized pyrethroid using modified World Health Organization tube bioassays and biochemical analysis of metabolic enzyme expressions pre- and post-PBO exposure. Mosquito eggs and larvae were collected from three cities in Orange County in July 2020 and reared in insectary, and F₀ adults were used in this study. A JHB susceptible strain was used as a control. Mosquito mortalities and metabolic enzyme expressions were examined in mosquitoes with/without pre-exposure to different PBO concentrations and exposure durations. Except for malathion, wild strain Cx quinquefasciatus mosquitoes were resistant to all insecticides tested, including PBO-synergized pyrethroids (mortality range 3.7 ± 4.7% to 66.7 ± 7.7%). Wild strain mosquitoes had elevated levels of carboxylesterase (COE, 3.8-fold) and monooxygenase (P450, 2.1-fold) but not glutathione S-transferase (GST) compared to susceptible mosquitoes. When wild strain mosquitoes were pre-exposed to 4% PBO, the 50% lethal concentration of deltamethrin was reduced from 0.22% to 0.10%, compared to 0.02% for a susceptible strain.The knockdown resistance gene mutation (L1014F) rate was 62% in wild strain mosquitoes. PBO pre-exposure suppressed P450 enzyme expression levels by 25∼34% and GST by 11%, but had no impact on COE enzyme expression. Even with an optimal PBO concentration (7%) and exposure duration (3h), wild strain mosquitoes had significantly higher P450 enzyme expression levels after PBO exposure compared to the susceptible laboratory strain. These results further demonstrate other studies that PBO alone may not be enough to control highly pyrethroid-resistant mosquitoes due to multiple resistance mechanisms. Mosquito resistance to PBO-synergized insecticide should be closely monitored through a routine resistance management program for effective control of mosquitoes and the pathogens they transmit.

Diapause is a hormonally driven response which is triggered by environmental cues that signal impending adverse conditions and prompts metabolic, developmental, and behavioral changes to allow survival until the return of favorable conditions. Microbial symbionts have been shown to influence the metabolism, development, and behavior of their host organisms, all of which are common diapause-associated characteristics. Surveys of bacterial components in relation to diapause have been examined in few systems, of which the species are usually inactive during dormancy, such as eggs or pupae. This is specifically intriguing as adult female diapause in Culex pipiens (Diptera: Culicidae) can last between 4 and 7 mo and females remain mobile within their hibernacula. Furthermore, it is unknown how microbiota changes associated with prolonged dormancy are different between the lab and field for insect systems. This study aims to characterize how the microbiota of C. pipiens changes throughout diapause under both field and lab settings when provided identical food and water resources. Based on these studies, C. pipiens microbiota shifts as diapause progresses and there are considerable differences between field and lab individuals even when provided the same carbohydrate and water sources. Specific bacterial communities have more association with different periods of diapause, field and lab rearing conditions, and nutritional reserve levels. These studies highlight that diapausing mosquito microbiota studies ideally should occur in field mesocosms and at multiple locations, to increase applicability to wild C. pipiens as prolonged exposure to artificial rearing conditions could impact metrics related to diapause-microbiome interactions. Additionally, these findings suggest that it would be worthwhile to establish if the microbiota shift during diapause impacts host physiology and whether this shift is critical to diapause success.

Aedes albopictus (Skuse) and Aedes aegypti (Linnaeus) (Diptera: Culicidae) mosquitoes transmit pathogenic arthropod-borne viruses, including dengue, chikungunya, and Zika viruses, with significant global health consequences. Both Ae. albopictus and Ae. aegypti also are susceptible to Aedes flavivirus (AEFV), an insect-specific flavivirus (ISF) first isolated in Japan from Ae. albopictus and Ae. flavopictus. ISFs infect only insect hosts and evidence suggests that they are maintained by vertical transmission. In some cases, ISFs interfere with pathogenic flavivirus infection, and may have potential use in disease control. We explored the host range of AEFV in 4 genera of mosquitoes after intrathoracic injection and observed greater than 95% prevalence in the species of Aedes and Toxorhynchites tested. Anopheles and Culex species were less permissive to infection. Vertical transmission studies revealed 100% transovarial transmission and a filial infection rate of 100% for AEFV in a persistently-infected colony of Ae. albopictus. Horizontal transmission potential was assessed for adult and larval mosquitoes following per os exposures and in venereal transmission experiments. No mosquitoes tested positive for AEFV infection after blood feeding, and infection with AEFV after sucrose feeding was rare. Similarly, 2% of adult mosquitoes tested positive for AEFV after feeding on infected cells in culture as larvae. Venereal transmission of AEFV was most frequently observed from infected males to uninfected females as compared with transmission from infected females to uninfected males. These results reveal new information on the infection potential of AEFV in mosquitoes and expand our understanding of both vertical and horizontal transmission of ISFs.

Rickettsioses are among emerging infectious diseases around the world. In Madagascar, little information is available regarding Rickettsia (Rickettsiales: Rickettsiaceae) diversity and their potential impacts on public health. In fact, molecular screening of ectoparasites of mammals reported the presence of three species, Rickettsia africae, Rickettsia typhi, and Rickettsia felis. The present study aims to investigate the diversity of Rickettsia in small mammals and associated ectoparasites (fleas and ticks) using a molecular approach. In September and December 2016, fieldworks were undertaken in two districts of Madagascar to capture small mammals using standard traps (Tomahawk and Sherman traps) and collect associated ectoparasites. In total, 12 taxa of ectoparasites (5 flea and 7 tick species) were collected from 89 individuals of four species of terrestrial small mammals. Rickettsia spp. were molecularly identified in one specimen of Rattus rattus (Rodentia: Muridae), one specimen of Pulex irritans (Siphonaptera: Pulicidae) as well as four specimens of Ixodes cf. colasbelcouri (Ixodida: Ixodidae). This study showed the presence of three phylogenetically distinct taxa of Rickettsia in small mammals and their ectoparasites. The current study broadens our knowledge on the diversity of Rickettsia in the Central Highlands of Madagascar and highlights for the first time the presence of Ri. felis in R. rattus and in tick, I. cf. colasbelcouri in Madagascar. Additional studies are needed to have exhaustive information on Rickettsia in small mammals and their ectoparasites, to determine their pathogenicity as well as their potential effects on public health in order to update the national policy for the control of emerging infectious diseases in Madagascar.

Trypanosoma cruzi is the causative agent of Chagas disease in humans and dogs in the Americas. Transmission predominantly occurs via the feces of infected kissing bugs (Hemiptera: family Reduviidae; subfamily Triatominae) contaminating bite site wounds or mucous membranes. To better understand Chagas disease entomologic risk in Oklahoma, kissing bugs collected from within the state were tested for T. cruzi DNA. Data including county of insect collection, species and instar, and specific locations where specimens were found were collated. Triatomines were also tested by PCR to potentially identify DNA of vertebrate species on which specimens had recently fed. In total, 110 kissing bugs from 22 counties were tested. All triatomines were identified as Triatoma sanguisuga nymphs or adults, with the exception of one possible T. lecticularia adult. Trypanosoma cruzi DNA was detected in 22 (20%) triatomines from 12 counties spanning the state. The majority of T. cruzi PCR positive kissing bugs were found inside homes or associated structures (i.e., garages, porches). Vertebrate DNA was identified in 27 (24.5%) triatomines, with human DNA detected in 25 (92.6%) of these specimens, and canine and raccoon DNA detected in one specimen each (3.7%).Two specimens tested positive for both T. cruzi and human DNA and one specimen tested positive for both T. cruzi and raccoon DNA. Results from this study indicate that kissing bugs carrying T. cruzi are widespread in Oklahoma, that positive kissing bugs infest homes and associated structures, and that human-vector, canine-vector, and wildlife-vector contact all occur within the state.

Trypanosomatids (Kinetoplastida:Trypanosomatidae) protozoa are a diverse group of obligate parasites. The genera Trypanosoma and Leishmania are the most studied because of their medical importance. This work aims to evaluate the effects of anthropization processes on the composition of the phlebotomine sand fly fauna and the natural infection by Trypanosomatids, with emphasis on Leishmania. At all 3,186 sand flies were collected, distributed in 13 genera and 52 species, being Ny. umbratilis the most abundant species. There was no difference in the diversity between canopy and soil environments. The species abundance and richness were higher in the forest environment while species diversity and evenness were highest in the forest edge. The ITS1 region was used by PCR-RFLP to identify the fragment profiles of Leishmania species, followed by genetic sequencing. Here were analyzed 100 pools of female sand flies, being six positive for DNA parasite. PCR-RFLP fragment patterns similar to Endotrypanum sp. were observed in Nyssomyia anduzei, Psychodopygus amazonensis and Lutzomyia gomezi, and those fragments similar to Leishmania (Leishmania) amazonensis were observed in Bichromomyia flaviscutellata. ITS1 sequencing confirmed the presence of Leishmania sp. in Bi. flaviscutellata, and Leishmania (Viannia) naiffi in Ny. anduzei, Psychodopygus amazonensis, and Lu. gomezi. This is the first record of Lu. gomezi and Ps. amazonensis infection by L. naiffi in the State of Amazonas. These results show the trypanosomatid infection in sandflies from different landscapes in a rural settlement, and the finding of species infected with L.(V.) naiffi suggest that they can develop a role in the transmission cycle of leishmaniasis.

Detection of Orientia tsutsugamushi DNA in a trombiculid mite chigger species suggests that it might be a potential vector of scrub typhus in an endemic area. Over a period of 20 mo, 85 rats were trapped, 57 had chiggers that were identified by standard morphometric techniques. The chigger pools were assessed by performing PCR assays targeting fragments of the single-copy genes 56 kDa type-specific antigen gene (TSA56) by nested PCR and the 47 kDa (htrA) quantitative real-time PCR (qPCR). The novel traD SYBR green assay that detects a multicopy gene was also performed. In total, 27 chigger pools were positive by traD qPCR, of which only 7 were positive by 47 kDa qPCR and in 3 of these, 56 kDa gene was amplified by nested PCR. Orientia tsutsugamushi-specific DNA was detected in Ascoschoengastia spp., Schoengastiella ligula, Leptotrombidium rajasthanense, Leptotrombidium deliense, and Leptotrombidium jayawickremei chigger pools. Therefore, they could be potential vectors of scrub typhus in Southern India. The three 56 kDa sequences belonged to TA716 genotype and Kato genogroup. Further studies are needed to confirm these chigger species as scrub typhus vectors in Northern Tamil Nadu.

The range of ticks in North America has been steadily increasing likely, in part, due to climate change. Along with it, there has been a rise in cases of tick-borne disease. Among those medically important tick species of particular concern are Ixodes scapularis Say (Acari: Ixodidae), Dermacentor variabilis Say (Acari: Ixodidae), and Amblyomma americanum Linneaus (Acari: Ixodidae). The aim of this study was to determine if climate factors explain existing differences in abundance of the three aforementioned tick species between two climatically different regions of Illinois (Central and Southern), and if climate variables impact each species differently. We used both zero-inflated regression approaches and Bayesian network analyses to assess relationships among environmental variables and tick abundance. Results suggested that the maximum average temperature and total precipitation are associated with differential impact on species abundance and that this difference varied by region. Results also reinforced a differential level of resistance to desiccation among these tick species. Our findings help to further define risk periods of tick exposure for the general public, and reinforce the importance of responding to each tick species differently.

Indonesia has rich Anopheline (Diptera: Culicidae) mosquito species living in various types of ecosystems. The study was conducted to profile and compare Anopheles diversity, equitability, and dominance in various ecosystems using different animal-based sampling techniques. The present study analyzed a subset of data collected from a nation-wide vector and animal reservoirs survey in 2016. Analyses were restricted to three ecosystem types (forest, nonforest, and coastal areas) in Java and Sumatera Islands. A total of 5,477 Anopheles were collected by using animal-baited (n = 1,909) and animal-baited trap nets (n = 1,978), consisting of 23 Anopheline species. Overall, Anopheles vagus was the most abundant species, followed by An. subpictus and An. barbirostris. Among the three ecosystems, the forest had a higher diversity index (H′ = 1.98), but each ecosystem has its specific predominant species. Compared with the animal-baited method, the Anopheles abundance collected by animal-baited trap nets was two-fold higher. Ecosystem, elevation, and sampling methods were associated with the abundance of female Anopheles (P-value < 0.001). Our findings revealed that Anopheles were found in a different ecosystem, indicating the potential of malaria transmission.This suggests that improved malaria vector surveillance is essential in all types of ecosystem. Furthermore, the study suggested that animal-baited trap nets could be used as the standard method of outdoor resting sampling in Indonesia in addition to the traditional human landing collection approach.

An endemic focus of cutaneous leishmaniasis (CL) is located in the Sutlej River Valley in Himachal Pradesh (India) in the north-western Himalaya where CL co-exists with visceral leishmaniasis (VL). In areas of the Indian subcontinent such as Rajasthan, cutaneous leishmaniasis is transmitted by Phlebotomus papatasi (Scopoli) and Phlebotomus salehi. In Himachal Pradesh, Phlebotomus longiductus (Parrot) is suspected to be the vector for CL. In the current study, sand flies were collected and tested for Leishmania infection and to confirm the vector species causing CL. Sand flies were collected during April and September of 2017–2019 from CL endemic villages of Rampur (Shimla), Nirmand (Kullu) and Nichar (Kinnaur) districts of Himachal Pradesh. The sand flies were identified as Phlebotomus (adlerius) longiductus (Parrot) and Phlebotomus (larrousisus) major (Annandale). The density of P. longiductus was found highest. The elevation of villages ranged from 947 m to 2,130 m and were far from the presence of subsoil water. Field collected sand flies tested positive (7.69%) for Leishmania donovani by PCR-RFLP. The L. donovani sequences detected from P. longiductus were 97% similar to L. donovani sequences reported from the cases of CL in Himachal Pradesh.The Leishmania positive sand flies were morphologically identified as Phlebotomus adlerious longiductus providing one step further evidence towards the vector status of CL in Himachal Pradesh. The findings of the study are of epidemiological significance for strategic planning of vector control for leishmaniasis in India.

In the United States, surveillance has been key to tracking spatiotemporal emergence of blacklegged ticks [Ixodes scapularis Say (Ixodida:Ixodidae)] and their pathogens such as Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner (Spirochaetales: Spirochaetaceae), the agent of Lyme disease. On the Holt Research Forest in midcoastal Maine, collection of feeding ticks from live-trapped small mammal hosts allowed us to track the emergence and establishment of I. scapularis, 1989–2019. From 1989–1995, we collected only I. angustus Neumann (Ixodida: Ixodidae)(vole tick), Dermacentor variabilis Say (Ixodida: Ixodidae) (American dog tick), and I. marxi Banks (Ixodida: Ixodidae) (squirrel tick) from seven species of small mammals. The most abundant tick host was the white-footed mouse [Peromyscus leucopus Rafinesque (Rodentia:Cricetidae)] followed by the red-backed vole (Myodes gapperi Vigors (Rodentia: Cricetidae)). Emergence of I. scapularis was signaled via the appearance of subadult I. scapularis in 1996. Emergence of B. burgdorferi was signaled through its appearance in I. scapularis feeding on mice in 2005. There was a substantial increase in I. scapularis prevalence (proportion of hosts parasitized) and burdens (ticks/host) on white-footed mice and red-backed voles in 2007.The ∼11-yr time-to-establishment for I. scapularis was consistent with that seen in other studies. White-footed mice comprised 65.9% of all captures and hosted 94.1% of the total I. scapularis burden. The white-footed mouse population fluctuated interannually, but did not trend up as did I. scapularis prevalence and burdens. There were concurrent declines in I. angustus and D. variabilis. We discuss these results in the broader context of regional I. scapularis range expansion.

The public health challenge posed by tick-borne disease (TBD) has increased efforts to characterize the spatial and temporal distribution of ticks and associated pathogens to better focus tick control strategies and personal protection measures. We describe variability in nymphal Ixodes scapularis Say and Amblyomma americanum (L.) density derived from daily drag sampling at a single location in New Jersey over 4 yr and explore how observed differences in daily collections might affect the estimation of acarological risk. We found significant variability in the density of host-seeking nymphs that could suggest substantially different rates of human-tick encounters depending on sampling date, habitat, and ambient weather conditions. The spatial and temporal variability in the distribution of 2 sympatric tick species with different host preferences and questing strategies, suggests that to produce results that are comparable among sites across the area sampled, surveillance efforts may be limited to shorter collection seasons, fewer sites or less sampling effort (fewer plots or fewer visits) per site, and a geographic scope that minimizes the potential temporal and spatial biases indicated here. Our results illustrate that evaluation of models of tick distribution or relative acarological risk based on surveillance data requires a full description of the diversity of habitats sampled and the conditions under which sampling is performed. The array of factors that affect tick host-seeking and that could bias interpretation of sampling results emphasizes the need to standardize sampling protocols and for more caution when interpreting tick sampling data collected over large temporal and spatial scales.

Lyme disease, caused by Borrelia burgdorferi sensu stricto and most commonly transmitted by Ixodes scapularis Say (Ixodida: Ixodidae), is the most common tick-borne disease in Maryland. Because B. burgdorferi s.s. is maintained in enzootic cycles among wild mice (Peromyscus spp) and Ixodes spp ticks, differing patterns of parasitism of ticks on mice could impact the infection prevalence with B. burgdorferi. We determined the infection prevalence of Peromyscus spp as well as questing and partially engorged nymphal ticks collected at six sites on private land in five counties in Maryland from May to August 2020. Questing nymph infection prevalence (NIP) was 14%. We trapped 1258 mice and collected 554 ticks and 413 ear tissue samples. The prevalence of infested Peromyscus spp varied based on host age and sex, with older and male mice more likely to be infested. We detected a significant difference amongst the proportion of attached Ixodes and the location of trapping. Similarly, the prevalence of B. burgdorferi infected Peromyscus spp mice varied between locations (average mouse infection prevalence was 40%), with the highest prevalence in locations where Ixodes were the most commonly found ticks. The B. burgdorferi infection prevalence in partially engorged I. scapularis nymphs retrieved from Peromyscus spp was ∼36% which lends further support to the host infection prevalence. Local differences in distribution of infected vectors and reservoirs are important factors to consider when planning interventions to reduce Lyme disease risk.

The development of insecticide resistance in different species of mosquitoes to Pyrethroids is a major challenge for vector-borne diseases transmitted by mosquitoes. Failure of Pyrethroids in control of mosquitoes would impact negatively on the gains recorded in control of mosquito-borne diseases in previous years. In anticipation of a country-wide deployment of Pyrethroid-treated nets for control of mosquito-borne diseases in Nigeria, this study assessed susceptibility of Culex quinquefasciatus Say. (Diptera: Culicidae) to Pyrethroids in Owhelogbo, Ejeme and Oria-Abraka communities in Delta State, Niger-Delta, Nigeria. Three to five day old Cx. quinquefasciatus were exposed to Deltamethrin (0.05%), Permethrin (0.75%), and Alphacypermethrin (0.05%) using World Health Organization bioassay method. Polymerase chain reaction (PCR) was employed in characterization of species and knockdown mutation. Results revealed that Cx. quinquefasciatus were generally susceptible (98-100%) to Deltamethrin, Permethrin, and Alphacypermethrin in the three communities with the exception of Owhelogbo where resistance to Deltamethrin (97%) was suspected. Knockdown time to Deltamethrin (11.51, 11.23, and 12.68 min), Permethrin (28.75, 13.26, and 14.49 min), and Alphacypermethrin (15.07, 12.50, and 13.03 min) were considerably low for Owhelogbo, Ejeme, and Oria-Abraka Cx. quinquefasciatus populations, respectively. Species identification result showed that all amplified samples were Cx. quinquefasciatus; however, no kdr allele was found in the three populations. Deployment of pyrethroid-treated nets for control of mosquito-borne diseases in Niger-Delta region of Nigeria is capable of reducing burden of diseases transmitted by Cx. quinquefasciatus as well as addressing nuisance value of the vector; however, caution must be entertained so as not to increase selection pressure thereby aiding resistance development.

To date, Triatoma dimidiata sensu lato [Reduviidae:Triatominae (Latreille 1811)] remains the sole vector species associated with Chagas disease transmission reported from Belize. Human infection data are limited for Belize and the disease transmission dynamics have not been thoroughly investigated, yet the likelihood of autochthonous transmission is supported by the widespread collection of infected vectors from within local households. Here, we report updated infection rates of the vector population and infestation rates for villages in north and central Belize. Overall, 275 households were enrolled in an ongoing vector surveillance program. Of the 41 insects collected, 25 were PCR positive for T. cruzi, indicating an infection rate as high as 60%.To further characterize the epidemiological risk of human–vector contact, determinants of household invasion were modeled. Local households were surveyed and characterized with respect to over 25 key factors that may be associated with household infestation by T. dimidiata s.l. While final models were not strongly predictive with respect to the risk factors that were surveyed, likely due to the low number of collection observations, the presence of domestic/peri-domestic dogs, nearby light sources, and household structure materials could be the focus of continued risk assessments. In northern Belize, this vector survey lends support to T. dimidiata s.l. inhabiting sylvatic settings as opposed to the classical paradigm of domiciliated vector populations. This designation has strong implications for the local level of human exposure risk which can help guide vector surveillance and control resources.

Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) play a paramount role in medical and veterinary entomology worldwide, particularly as vectors of pathogens which cause animal diseases. Biting midges are also infamous for the nuisance they provoke to people involved in outdoor activities. Nonetheless, attacks to man by midges from any Culicoides species have not been reported in Italy. An entomological investigation was performed following repeated attacks to man in a nature park near Rome (central Italy). The study area is a natural degassing zone, characterized by widespread hazardous gas emissions of CO₂ and H₂S, with several water bodies including permanent lakes, ponds, and pools. The biting midge C. riethi Kieffer, 1914 was very active during daytime in the period April–June. The species has been identified as responsible for attacks on people in the area. An in-depth analysis of the extreme environmental conditions revealed the ability of larvae to thrive in several water bodies, characterized by an extremely low pH and a high concentration of sulfates.

Graphical Abstract

View of the area from WB_b (white lake top right) to WB_d with reported the pH value of each water body (WB), the presence/absence and density of Culicoides riethi larvae and Hydroglyphus geminus along the pH gradient. Larval density is highest where pH levels do not allow the development of its possible predator.

Argas brumpti Neumann is a large argasid (soft) tick that inhabits the drier areas of eastern and southern Africa. This species typically feeds on a wide variety of small to large mammals (including humans) and lizards, and resides in shallow caves, rocky areas, or dust-bath areas used by large mammals. Individuals of this species, collected as nymphs and adults from a semidesert area of Kenya and subsequently maintained under constant conditions in the laboratory, survived for 27 yr. Furthermore, after 8 yr of starvation and at least 4 yr after the last male died, at least one female laid eggs.The progeny developed into considerable numbers of both males and females, some of which are still living after 26 yr.The longevity of these ticks is apparently a record for any species of tick. The delay in reproduction likely represents long-term storage of viable sperm, also apparently a record for any species of tick.

Multiple oviposition attractants are used for Culex (Diptera: Culicidae) mosquito surveillance in the CDC Gravid Trap, including hay and fish emulsion-infused water. Despite the use of both in the United States, no research has compared their attractiveness. We conducted trapping throughout Louisiana to assess the attractiveness of hay and fish emulsion-infused water in various habitat types and climates. Our results indicate that fish emulsion-infused water attracts more mosquitoes overall, more Culex quinquefasciatus (Say, 1823), and a wider diversity of mosquitoes than hay-infused water. This trend was maintained, regardless of habitat type or climate.

The soft tick Carios kelleyi (Cooley and Kohls, 1941) is an ectoparasite of bats that can harbor bacteria known to cause disease in humans, such as Rickettsia spp., Bartonella spp., and relapsing fever Borrelia spp. Human-tick encounters may occur when bats occupy attics or similar dwellings with access points to human-inhabited areas. During May 2021, a partially engorged adult female C. kelleyi was collected from a Vermont home with an attic that was being used as a roost by big brown bats, Eptesicus fuscus (Chiroptera: Vespertilionidae). The source of the blood in the tick was the domestic dog, Canis lupus familiaris. Subsequently, eight C. kelleyi larvae were collected from a rescued E. fuscus adult. This is the first report of a soft tick species from Vermont and it is unknown how long C. kelleyi has been present in this state. Reports of C. kelleyi are on the rise across the northeastern United States but the implications for the health of humans, domestic animals, and bats in northern New England remain unclear. Bat management plans should consider the importance of bat exclusion in preventing tick encounters with members of the household and should include a tick monitoring component if bats are evicted.

Methyl benzoate (MBe) is a volatile organic molecule found in various plants; it is used as an insect semiochemical. MBe also has a biorational insecticidal effect against various agricultural and urban arthropod pests. The present study was the first to assess the larvicidal potential of MBe against fourth-instar larvae of the mosquitoes Aedes albopictus (Skuse) and Culex pipiens (L.). A positive association was observed between MBe concentrations and larval mortality in both the species.The highest mortality recorded was 100% for Ae. albopictus and 56% for Cx. pipiens after 24 h of exposure to 200 ppm MBe.The lethal median concentration (LC₅₀) values of MBe against fourth-instar larvae of Ae. albopictus and Cx. pipiens were 61 ppm and 185 ppm, respectively. These results suggest that MBe has great potential for use as an environmentally friendly larvicidal agent for mosquito control.

Graphical Abstract

The Musca domestica salivary gland hypertrophy virus (MdSGHV) is known to have marked effects on the female Musca domestica L. (or common house fly) reproductive system, particularly regarding the size and functionality of the ovaries. Examination of the terminal ovarian follicles can help determine if and how MdSGHV mechanistically causes the block in ovarian development. In this study, terminal ovarian follicle lengths were measured and monitored for patency using Trypan blue dye staining. We examined the effect of MdSGHV infection on female house fly ovarian follicles and attempted to rescue the diminished ovarian follicles in MdSGHV-infected house flies through the application of a hormonal treatment (i.e., methoprene). Comparison of patency in control saline-injected females, virus-injected females with no methoprene application, and virus-injected females with topical methoprene application revealed that none of the virus-infected flies showed an increase in terminal follicular length beyond stage 3 follicles (staging according to Adams 1974). Additionally, none showed evidence of patency. In control, saline-injected females, we found the threshold length of the terminal follicles for the onset of patency to be 600 µm. When examined at 48, 72, and 96 h post-eclosion, average follicle length for infected females seldom reached 250 µm and they also failed to display patency. Thus, the virus is somehow involved in shutting down the mechanism involved in follicular patency. The lack of patency in infected follicles may also be one of the determining factors preventing vertical transmission of the pathogen.