Species identification of mosquitoes (Diptera: Culicidae) based on morphological characteristics remains often difficult in field-collected mosquito specimens in vector-borne disease surveillance programs. The use of DNA barcodes has been proposed recently as a tool for identification of the species in many diverse groups of animals. However, the efficacy of this tool for mosquitoes remains unexplored. Hence, a study was undertaken to construct DNA barcodes for several species of mosquitoes prevalent in India, which included major vector species. In total, 111 specimens of mosquitoes belonging to 15 genera, morphologically identified to be 63 species, were used. This number also included multiple specimens for 22 species. DNA barcode approach based on DNA sequences of mitochondrial cytochrome oxidase gene sequences could identify 62 species among these, in confirmation with the conventional taxonomy. However, two closely related species, Ochlerotatus portonovoensis (Tiwari & Hiriyan) and Ochlerotatus wardi (Reinert) could not be identified as separate species based on DNA barcode approach, their lineages indicating negligible genetic divergence (Kimura two-parameter genetic distance = 0.0043).

Parichoronyssus bakeri new species was found on two phyllostomid bats species, the greater spear-nosed bat, Phyllostomus hastatus (Pallas), and the lesser spear-nosed bat, Phyllostomus elongatus (E. Geoffroy), in Pakitza, National Park Manu, Madre de Dios, Peru, including additional material examined from Venezuela. The female, male, deutonymph, and protonymph are described and illustrated. A key to the seven species of Parichoronyssus is provided.

RESUMEN Se describe la hembra, macho, deutoninfa y protoninfa de Parichoronyssus bakeri nueva especie, la cual fue hallada sobre dos especies de murciélagos filostómidos, Phyllostomus hastatus (Pallas) y Phyllostomus elongatus (E. Geoffroy) en Pakitza, Parque Nacional Manu, Madre de Dios, Perú, incluyendo registros adicionales de material examinado de Venezuela. Se presenta una clave para las siete especies del género Parichoronyssus.

Clay pots were analyzed as devices for sampling the outdoor resting fraction of Anopheles gambiae Giles (Diptera: Culicidae) and other mosquito species in a rural, western Kenya. Clay pots (Anopheles gambiae resting pots, herein AgREPOTs), outdoor pit shelters, indoor pyrethrum spray collections (PSC), and Colombian curtain exit traps were compared in collections done biweekly for nine intervals from April to June 2005 in 20 housing compounds. Of 10,517 mosquitoes sampled, 4,668 An. gambiae s.l. were sampled in total of which 63% were An. gambiae s.s. (46% female) and 37% were An. arabiensis (66% female). The clay pots were useful and practical for sampling both sexes of An. gambiae s.l. Additionally, 617 An. funestus (58% female) and 5,232 Culex spp. (males and females together) were collected. Temporal changes in abundance of An. gambiae s.l. were similarly revealed by all four sampling methods, indicating that the clay pots could be used as devices to quantify variation in mosquito population density. Dispersion patterns of the different species and sexes fit well the negative binomial distribution, indicating that the mosquitoes were aggregated in distribution. Aside from providing a useful sampling tool, the AgREPOT also may be useful as a delivery vehicle for insecticides or pathogens to males and females that enter and rest in them.

The population dynamics of sand flies (Diptera: Psychodidae) were studied in Sanlıurfa province in southeastern Turkey, in the country’s largest focus of typical anthroponotic cutaneous leishmaniasis, during 2000–2002. Sand flies were collected at nine different sampling stations, located throughout the city, representing a cross section of urban and rural habitats. In total, 29,771 sand flies were collected, 45.35% of which were Phlebotomus papatasi Scopoli. In this study, the overall sand fly species diversity, relative abundance of each species, biodiversity, and similarity indices among sampling stations and efficiency of trapping methods were evaluated. Among the sampling stations, Sanlıurfa city center and Suruç were shown to have the highest number of sand fly species; Harran-Akcakale and Hilvan habitats produced the largest number of individuals. The greatest similarity rates (80%) in terms of sand fly species were observed between Hilvan and city center, Harran-Akcakale and city center, Harran-Akcakale and Yenice, and Siverek and Viransehir. The lowest similarity rate (16%) was observed between Bozova-Birecik and city center. Comparison of biodiversity and similarity indices between the various sampling stations reveals the distribution of the suspected vector species and provides basic knowledge required to develop logical and effective control strategies. Among the trapping methods used, light traps showed the highest capture efficiency, above aspirators and sticky papers. It was concluded that light traps alone were sufficient to determine the sand fly fauna of the study area. It is recommended that the spatial and temporal dynamics of sand fly populations be monitored throughout the southeastern Anatolia Project (GAP) construction period, considering the potential impact the project may have on mean temperature, humidity, and human population movements.

CDC miniature light traps were used to evaluate the general biology of phlebotomine sand flies from April 2003 to November 2004 at Tallil Air Base, Iraq. Factors evaluated include species diversity and temporal (daily and seasonal) and geographic distribution of the sand flies. In addition, the abundance of sand flies inside and outside tents and buildings was observed. In total, 61,630 sand flies were collected during 1,174 trap nights (mean 52 per trap, range 0–1,161), with 90% of traps containing sand flies. Sand fly numbers were low in April, rose through May, were highest from mid-June to early September, and dropped rapidly in late September and October. More than 70% of the sand flies were female, and of these sand flies, 8% contained visible blood. Phlebotomus alexandri Sinton, Phlebotomus papatasi Scopoli, Phlebotomus sergenti Parrot, and Sergentomyia spp. accounted for 30, 24, 1, and 45% of the sand flies that were identified, respectively. P. alexandri was more abundant earlier in the season (April and May) than P. papatasi, whereas P. papatasi predominated later in the season (August and September). Studies on the nocturnal activity of sand flies indicated that they were most active early in the evening during the cooler months, whereas they were more active in the middle of the night during the hotter months. Light traps placed inside tents with and without air conditioners collected 83 and 70% fewer sand flies, respectively, than did light traps placed outside the tents. The implications of these findings to Leishmania transmission in the vicinity of Tallil Air Base are discussed.

Buggy Creek virus (family Togaviridae, genus Alphavirus, BCRV) is an alphavirus within the western equine encephalitis virus complex whose primary vector is the swallow bug, Oeciacus vicarius Horvath (Hemiptera: Cimicidae), an ectoparasite of the colonially nesting cliff swallow, Petrochelidon pyrrhonota, that is also a frequent host for the virus. We investigated ecological correlates of BCRV infection in 100-bug pools at 14 different swallow colony sites in southwestern Nebraska from summer 2004, by using plaque assay on Vero cells to identify cytopathic virus and reverse transcription-polymerase chain reaction to identify noncytopathic viral RNA. We found 26.7% of swallow bug pools positive for BCRV, with 15.6% showing cytopathic (“infectious”) virus and 11.0% noncytopathic (“noninfectious”) viral RNA. The prevalence of cytopathic BCRV increased with cliff swallow colony size in the current year; the percentage of noncytopathic samples at a site did not vary with colony size in the current year but increased with the previous year’s colony size at a site. Active colony sites (those used by swallows) had higher percentages of cytopathic BCRV in bug pools than at inactive colony sites, but the reverse held for noncytopathic viral RNA. Nests that were occupied by birds at some time in the season had more pools with cytopathic BCRV than did inactive nests. Colonies used by birds for the first or second time had less virus in bugs than did sites that had had a longer history of bird use. The percentage of pools with BCRV was affected by whether bugs were clustering at nest entrances or distributed elsewhere on a nest. The prevalence of cytopathic samples decreased at inactive colony sites and increased at active sites over the course of the summer, whereas the reverse pattern held for noncytopathic samples. Noncytopathic bug pools seem to reflect infection patterns from a previous year. The results suggest that the birds play an important role in amplification of the virus and that the spatial foci of BCRV occurrence can be predicted based on characteristics of cliff swallow colonies and the cimicid bugs that are associated with them.

The definition and phylogenetic placement of the autogenous molestus form of Culex pipiens has puzzled entomologists for decades. We identified genetic differences between Cx. p. pipiens (L.) and Cx. pipiens f. molestus Forskål in the SH60 fragment described previously. Single-strand conformation polymorphism analysis, cloning, and sequencing of this fragment demonstrated high polymorphism within and among individual Cx. p. pipiens, with common SH60 variants shared among individuals from distant locations. In contrast, Cx. pipiens f. molestus from New York City each contained a single SH60 variant, which was not identified in any other Cx. p. pipiens specimens analyzed. Supporting microsatellite analysis demonstrated significant but reduced gene flow between Cx. p. pipiens and Cx. pipiens f. molestus in New York relative to Cx. p. pipiens populations in New York and California. Results are discussed in the context of two contrasting hypotheses regarding the origin of Cx. pipiens f. molestus populations.

Multiple families representing all possible combinations of crosses between the two molecular forms of Anopheles gambiae sensu stricto Giles and their hybrids were set up using forced mating between offspring of wild-collected females. The results showed that the reproductive output of hybrids and their backcrosses was similar to that of the pure forms as measured by egg batch size, hatching rate, and larval development success. No sex ratio distortion was found among the offspring. We concluded that postmating developmental barriers do not contribute to the isolation between the molecular forms.

Given that tools for dengue emergency control are limited, continuous evaluation of the effectiveness of insecticide applications in the field is of utmost importance. Such studies will provide a sound basis for defining spraying schemes for public health authorities in dengue-affected countries. In this article, we address the following research questions: How do different space spraying strategies affect Aedes aegypti (L.) (Diptera: Culicidae) populations in both space and time? More specifically, how well are these mosquitoes killed, and how quickly do their populations recover and from where? Field trials were carried out with ultralow volume sprayers in Kamphaeng Phet province, Thailand, with a pyrethrin mixture that was applied 1) indoors only, 2) indoors plus outdoors, 3) indoors with a doubled spraying time, and 4) indoors with doubled spraying time plus outdoors. We found that within 7 d, Ae. aegypti populations recovered to ≈50% of their original numbers. Spraying the outdoor area and doubling the time sprayed per room only had a significant impact on mosquito numbers 1 d after spraying. Two and 7 d after spraying, these effects were no longer detected. By investigating the spatial arrangement of Ae. aegypti numbers, we found that during the first 2 d after spraying immigration from untreated areas extended ≈15 m into the sprayed area, whereas after 7 d this effect extended up to 50 m. Results are discussed in relation to ongoing dengue control efforts in Thailand.

Two cDNA sequences encoding Drosophila Ace-orthologous and -paralogous acetylcholinesterase precursors (AO- and AP-AChE precursors, respectively), were identified from the body louse, Pediculus humanus humanus L. In vitro inhibition studies with an insecticide-susceptible body louse strain exhibited a simplex inhibitory response of AChE. The I₅₀ values of fenitroxon and carbaryl were estimated to be 2.2 and 1.9 μM for the susceptible lice, respectively. The mRNA level of AP-AChE gene was 3.1- and 9.3-fold higher than that of AO-AChE gene in the abdomen and the combined parts of the head and thorax, respectively, suggesting, due to its abundance, the potential significance of the AP-AChE isoform in Pediculus human lice in association with the efficacy of AChE-targeting pediculicides.

The ectoparasites of a small mammal community within an intertidal zone in the upper Gulf coast region of Texas were studied to assess the seasonal variation in abundances of the mite Gigantolaelaps mattogrossensis (Fonseca) (Acari: Laelapidae) on the marsh rice rat, Oryzomys palustris (Harlan). Further study into the ecology and dynamics of this parasite–host relationship was deemed to be necessary to expand the understanding of these potential participants in the ecology of Bayou Hantavirus, an important causative agent of Hantavirus pulmonary syndrome. The objective of this study was to determine the effects of five predictor variables on mite abundance: prevalences of hosts, relative humidity, precipitation, temperature, and length of daylight. Mite abundance was modeled as a function of the five variables with analyses of variance and multiple regressions; however, because the predictor variables pertain to the sampling period rather than to the individual rodent host, the effective sample size was small and thus the sums of squares and cross products matrix was singular. We therefore developed and used a new method for estimating regression coefficients based on the “noise-addition method” (random residual variation) combined with a bootstrap step converting the reduced rank data to full rank, providing realistic estimates of confidence intervals for the regression statistics. The population abundances of mites fluctuated significantly across collecting periods. Humidity and precipitation were the most influential variables in explaining the variation in abundances of mites. Model interpretation suggests that G. mattogrossensis is a nidicolous parasite. These results provide a baseline understanding of the seasonal interactions between parasite and host.

Real-time TaqMan polymerase chain reaction (PCR) assays were developed for the identification of mosquito (Diptera: Culicidae) bloodmeals originating from three groups of native Australian mammals. Primers and probes were designed to amplify a partial fragment of the cytochrome b gene of the agile wallaby, Macropus agilis (Gould); brushtail possum, Trichosurus vulpecula (Kerr); and the consensus sequence of the four species of Australian flying fox: Pteropus alecto Temminck, Pteropus conspicillatus Gould, Pteropus poliocephalus Temminck, and Pteropus scapulatus Peters. When tested on DNA extracted from whole tissue, each assay was shown to be specific for the vertebrate host that it was designed to identify. To evaluate the TaqMan assays, 137 field-collected blood-fed mosquitoes were analyzed, from which 128 (93.4%) were identified using one of the assays. Compared with other PCR-based techniques for bloodmeal identification, the TaqMan assays are sensitive, specific, and provide a rapid result without the need for post-PCR manipulation and visualization of products.

Vector-borne flaviviruses have been traditionally grouped into either mosquito-borne or tick-borne group. However, this vector range specificity has sometimes been questioned because of the puzzling records of occasional isolation of mosquito-borne viruses from ticks and of tick-borne viruses from mosquitoes. In this study, host range of the flaviviruses representing not only the two vector-borne groups but also insect flaviviruses and vertebrate viruses that are not arboviruses was comprehensively reexamined by a serial passage experiment in vitro by using cell cultures derived from mosquitoes, ticks, and vertebrates. The results showed that the host range specificity in the four groups of viruses, based on replication for five consecutive passages as a criterion to evaluate the ability of viruses to replicate in three different cell cultures, agreed with the conventional grouping as well as phylogenetic clustering. Thus, this assay provides useful, supplementary information regarding host range for those flaviviruses when their natural host range is unknown, ambiguous, or questionable.

Flock House Virus (family Nodaviridae, genus Alphanodavirus, FHV) was originally isolated from grass grubs Costelytra zealandica (White) (Coleoptera: Scarabaeidae) in New Zealand and belongs to a family of divided genome, plus-sense RNA insect viruses. FHV replicates in insects, a nematode, plants, and yeast. We previously reported replication of FHV in four genera of mosquitoes and expression of green fluorescent protein in Aedes aegypti (L.) produced by an FHV-based vector. We report here that FHV multiplies vigorously in vivo in the malaria vectors Anopheles gambiae Giles and An. stephensi Liston and in vitro in a cell line derived from An. gambiae. In addition, FHV multiplies extensively in two other medically important insects, the tsetse fly, Glossina morsitans morsitans Westwood, and the reduviid bug Rhodnius prolixus Stal, extending its host range to four orders of insects (Coleoptera, Lepidoptera, Diptera, and Hemiptera). The virus disseminates in all the major tissues of the insects studied. Anopheles and Glossina show mortality when FHV is injected at a dose above 10⁴ plaque-forming units (pfu) or the virus accumulates to titer above 10⁸ pfu. A lower dose (10³ pfu) promotes more extensive virus multiplication and reduces mortality to <10%. No adverse effects are observed in Ae. aegypti, Culex pipiens pipiens L., and Armigeres subalbatus (Coquillett), when injected with a dose of up to 10⁷ pfu. Mosquitoes orally fed with FHV exhibited slower virus growth rate with lower mortality. Our results indicate that FHV has uniquely broad insect host range and that the virus can be used to study virus host interactions in a variety of medically important insects.

When virus and microfilariae are ingested concurrently by a mosquito, microfilariae (mf) may penetrate the mosquito midgut and introduce virus directly into the mosquito hemocoel, allowing mosquitoes to become infectious much sooner than normal and enhancing transmission of viruses by mosquitoes. Mansonella ozzardi (Manson) is a benign filarial nematode parasite of humans in Latin America and is transmitted by black flies (Diptera: Simuliidae) and biting midges (Diptera: Ceratopogonidae). Because M. ozzardi and dengue are sympatric, we wanted to know whether M. ozzardi mf had the ability to penetrate the midgut of Aedes aegypti (L.) (Diptera: Culicidae) and thus play a potential role in the enhancement of dengue transmission. To test this, the F1 progeny from locally collected Ae. aegypti were fed on M. ozzardi-infected human males in an endemic village in northern Trinidad. Mosquitoes were dissected at various times after feeding and examined for mf in the midguts and thoraces. Microfilariae penetrated the midguts of 43% of 63 mosquitoes that ingested mf. Overall, 11% of mf penetrated the midgut by 17 h after being ingested. The intensity of midgut penetration was positively correlated to the numbers of mf ingested. Because midgut penetration is a key requirement for mf enhancement to occur, the potential exists that M. ozzardi could be involved in the enhancement of dengue virus transmission.

West Nile virus (family Flaviviridae, genus Flavivirus, WNV) was first detected in the Tennessee Valley and in Alabama in August 2001. In summer 2002, intensive viral activity was seen, but in subsequent years, viral activity settled into an enzootic pattern. Here, we report an analysis of viral activity in the mosquito fauna in the Mid-South from 2002 (the first year viral activity was detected in mosquitoes) through 2005. Eight mosquito species were infected with WNV during 2002. However, viral activity was only detected in four species—Culex salinarius Coquillett, Culex erraticus Dyar & Knab, Coquillettidia perturbans Walker, and Aedes vexans Meigen—in multiple years. The greatest number of positive pools was in Cx. erraticus and Cx. salinarius. Despite being specifically targeted for collection, Aedes albopictus Skuse was only found to be infected during the epiornitic year (2002), suggesting that under enzootic transmission conditions its role as a bridge vector in the region may not be significant. Virus-positive pools of Cx. erraticus were identified from winter-resting and early season dry ice-baited trap collections in 2005, implicating this species in WNV overwintering in Alabama. Molecular analysis of individuals initially identified as members of the Culex pipiens L. complex suggested that alleles characteristic of Cx. pipiens predominated in mosquitoes collected in Huntsville, AL, whereas alleles in the Auburn, AL, population were predominately characteristic of Culex quinquefaciatus Say. The southern boundary of the overlap zone of the two species seems to be located primarily between Huntsville and Auburn, a distance of 350 km.

The current study evaluated the prevalence of Ehrlichia canis Donatien and Lestoquard in domestic dogs, Canis familiaris L., and Rhipicephalus sanguineus (Latreille) (Acari: Ixodidae) ticks from different areas of Brazil. In Monte Negro County (state of Rondônia, Brazilian western Amazon), the indirect immunofluorescence assay detected E. canis-reactive antibodies (titer ≥40) in 58/153 (37.9%) and 40/161 (24.8%) dogs from the urban and rural areas, respectively. These values were significantly different between the two areas. Ticks from a household in the urban area of Monte Negro, and from households in three other localities (162–165 adult ticks per household) in the state of São Paulo (SP) were tested by polymerase chain reaction (PCR) targeting an erlichial dsb gene fragment. The prevalence of infected ticks (given as minimal infection rate) was 2.3, 6.2, and 3.7% for populations 1 (Monte Negro), 2 (Jundiaí, SP), and 3 (São Paulo I, SP), respectively, which were statistically similar. In contrast, no infected tick was detected in population 4 (São Paulo II, SP). DNA sequences were determined for some of the PCR products generated from ticks and dogs from populations 1–3, being all identical to each other and to available sequences of E. canis in GenBank. These results reinforce previous records of E. canis-infecting dogs in Brazil. Natural infection of R. sanguineus ticks by E. canis is reported for the first time in Brazil, where this tick is the commonest species infesting dogs.

O presente estudo avaliou a prevalência da infecção por Ehrlichia canis Donatien e Lestoquard em cães domésticos, Canis familiaris L., e carrapatos Rhipicephalus sanguineus (Latreille) (Acari: Ixodidae) em diferentes áreas do Brasil. Pela Reação de Imunofluorescência Indireta (RIFI) (título ≥40), foram detectados anticorpos reativos para E. canis em 37.9% de 153 cães da área urbana e 24.8% de 161 cães da área rural do município de Monte Negro, estado de Rondônia, Amazônia brasileira. Carrapatos R. sanguineus (162 a 165 carrapatos adultos por população) de uma residência da área urbana de Monte Negro e de outras três localidades do estado de São Paulo foram testados por PCR para um fragmento do gene dsb de Ehrlichia. A prevalência de carrapatos infectados [avaliada como Prevalência Mínima de Infecção (PMI)] foi de 2.3, 6.2, e 3.7% para as populações 1 (Monte Negro), 2 (Jundiaí, SP), e 3 (São Paulo I, SP), respectivamente, sendo estes resultados similares. Nenhum carrapato infectado foi detectado na população 4 (São Paulo II, SP). Os produtos da PCR de alguns carrapatos e cães das populações 1, 2 e 3 foram seqüenciados, sendo as seqüências obtidas idênticas entre si e à seqüência de E. canis disponível no GenBank. Estes resultados reforçam estudos anteriores que relataram a infecção por E. canis em cães do Brasil, contudo relata pela primeira vez no Brasil a infecção natural por E. canis em carrapatos R. sanguineus, tido como o principal carrapato de cães no país.

The objective of this study was to test for associations between land cover data and the presence of mosquito larvae of the genera Aedes Meigen and Anopheles Meigen in northern Thailand at the landscape scale. These associations were compared with associations between larval habitat variables and the presence of mosquito larvae at a finer spatial scale. Collection data for the larvae of one Aedes species and three species-groups of Anopheles, all of which are involved in pathogen transmission, were used. A variety of northern Thai landscapes were included, such as upland villages, lowland villages and peri-urban areas. Logistic regression was used to evaluate associations. Generally, land cover and landscape variables explained the presence of larvae as well as did larval habitat variables. Results were best for species/species-groups with specific habitat requirements. Land cover variables act as proxies for the types of habitat available and their attributes. Good knowledge of the habitat requirements of the immature stages of mosquitoes is necessary for interpreting the effects of land cover.

Microsatellite markers were isolated and developed from Culex pipiens quinquefasciatus Say (Diptera: Culicidae) sampled in Johannesburg, South Africa, to identify those that are broadly useful for analyzing Cx. pipiens complex populations between continents. Suitable loci should be 1) inherited in a codominant Mendelian manner, 2) polymorphic, 3) selectively neutral, 4) randomly associated, 5) without null alleles, and 6) applicable across broad regions and between diverse biotypes. Loci in Cx. p. quinquefasciatus from Johannesburg ranged from two to 17 alleles per locus and expected heterozygosities (H_e) were 0.02–0.87. Loci in Cx. p. pipiens L. from Johannesburg had five to 19 alleles per locus and H_e values ranging from 0.57 to 0.93, whereas those from George, South Africa, had five to 17 alleles per locus and H_e values ranging from 0.54 to 0.88. Loci in North American mosquitoes were more variable. Cx. p. quinquefasciatus from South Carolina had five to 19 alleles per locus and H_e values ranging from 0.64 to 0.90, whereas Cx. p. pipiens from Massachusetts had six to 28 alleles per locus and with H_e values ranging from 0.65 to 0.94. All loci were associated randomly. Overall, four of nine of these new loci satisfied all six criteria for broad utility for analyzing the genetic structure of Cx. pipiens populations.

Phlebotomus papatasi (Scopoli) (Diptera: Psychodidae) is the most important vector of Leishmania major, and previous experiments revealed that Leishmania development in the sand fly midgut is significantly affected by temperature. Therefore, we maintained blood-fed P. papatasi females at 23 or 28°C to understand the effect of temperature on bloodmeal digestion and developmental times of this sand fly. At the lower temperature, the metabolic processes were slower and developmental times were longer: defecation, oviposition, and egg hatch started later and took longer to complete. Also, the mortality of blood-fed females was significantly lower. The defecation of bloodmeal remains was delayed for 12–36 h at 23°C compared with the group maintained at 28°C. Such delay would provide more time for Leishmania to establish the midgut infection and could partially explain the increased susceptibility of P. papatasi to Leishmania major at 23°C. In both experimental groups, blood-fed females laid similar numbers of eggs (mean 60 and 70, maximum 104 and 115 per female). Egg numbers were positively correlated with the amount of hematin excreted in feces of ovipositing females. In parallel experiments, autogeny was recorded in 8% of females. The autogenous egg batches were smaller (mean, 12; range, 1–39), but they all produced viable larvae.

A lethargic southern black racer, Coluber constrictor priapus Dunn and Wood, wild-caught in the Florida Keys, Monroe County, FL, was found to be paralyzed by the bite of a female ixodid tick, Amblyomma rotundatum Koch (Acari: Ixodidae). Removal of the tick restored the snake to normalcy within 18 h. Other, earlier reported cases of tick toxicosis in reptiles are reviewed and clarified. Evidently, the present incident is the only reported case of tick paralysis in a poikilotherm found in a natural setting.

Sixty-two questing adult Rhipicephalus sanguineus (Latreille) ticks were collected by direct removal from blades of turfgrass and adjacent concrete walkways at a suburban home in Riverside County, CA, and tested for the presence of Rickettsia, Bartonella, and Ehrlichia DNA. Polymerase chain reaction (PCR) was used to amplify fragments of the 17-kDa antigen gene and the rOmpA gene of the spotted fever group rickettsiae. One male tick contained R. rickettsii DNA; its genotype differed from R. rickettsii isolates found in Montana and Arizona that cause Rocky Mountain spotted fever and from Hlp#2 and 364D serotypes. One male tick and one female tick contained B. henselae DNA. No Ehrlichia platys or Ehrlichia canis DNAs were detected using nested PCR for their 16S rRNA genes. These findings extend the area where Rickettsia rickettsii may be vectored by Rh. sanguineus. Rh. sanguineus also may be infected with Bartonella henselae, a human pathogen that is typically associated with fleas and causes cat scratch disease.

Aedes aegypti (L.) is the primary vector of dengue viruses, a group of four serotypic single-stranded RNA viruses. Dengue virus RNA can be readily detected in fresh or dried infected mosquitoes by using reverse transcriptase-polymerase chain reaction (RT-PCR). The current study examined the persistence and limit of dengue virus RNA detection in infected Ae. aegypti killed and exposed to natural ambient tropical conditions of temperature and humidity. Under relatively harsh conditions, dengue RNA retained sufficient integrity to be detected in dried mosquitoes up to 13 wk after exposure to relatively high ambient temperatures (26.3–31.7°C) and relative humidity (49.4–69.9%). These findings confirm that the necessity for testing either fresh or frozen mosquitoes is not a prerequisite when using RT-PCR as the viral detection method, and under particular epidemiological circumstances it allows for a more convenient means of conducting vector–virus surveillance activities where collection methods and logistics may preclude immediate testing or access to a cold chain.

VlsE is a surface exposed lipoprotein of the Lyme disease spirochete, Borrelia burgdorferi. Spirochetes are able to generate many antigenic variants of VlsE by DNA recombination at the vlsE locus. Novel VlsE antigenic variants are readily observed in mice infected with B. burgdorferi. We followed a clonal population of spirochetes through a tick transmission cycle and report that unlike in vertebrates, the vlsE locus is stable in ticks.