Arkansas-Missouri has emerged as the primary U.S. focus of tularemia, which is caused by the National Institute of Allergy and Infectious Diseases Category A Priority Pathogen Francisella tularensis, over the past 30 yr. There are several pieces of indirect evidence suggesting that a key role of ticks in the transmission of F. tularensis to humans in Arkansas-Missouri is the primary reason why tularemia has remained a prominent disease of humans in this two-state area while fading away from other central or eastern states after a general decline in rabbit-associated tularemia cases. The primary tick vector(s) in Arkansas-Missouri can, based on a comparison of seasonal patterns of human tularemia cases and peak host-seeking activity of commonly human-biting tick species and life stages, be narrowed down to Amblyomma americanum (L.) nymphs, A. americanum adults, or Dermacentor variabilis (Say) adults. Unfortunately, currently available data cannot be used to further elucidate the relative roles of these ticks as vectors of F. tularensis to humans in Arkansas-Missouri. To address the fact that we do not know which tick species is the primary vector of F. tularensis to humans in the most prominent U.S. focus of tularemia, we need to determine 1) relative contributions of different tick species and life stages as human biters in Arkansas-Missouri; 2) natural rates of infection with F. tularensis tularensis (type A) and F. tularensis holarctica (type B) of the most prominent human-biting ticks in areas of Arkansas-Missouri hyperendemic for tularemia; 3) experimental vector efficiency of these ticks for both F. tularensis tularensis and F. tularensis holarctica; and 4) presence of infection with F. tularensis tularensis or F. tularensis holarctica in ticks collected from humans in Arkansas-Missouri.

Salivary glands of Dermatobia hominis (L., Jr.) (Diptera: Oestridae) larvae were studied under light and electron microscopy. The salivary glands of second (L₂) and third instars (L₃) are similar and consist of pairs of translucent tubules. The individual efferent ducts unite to form a single deferent duct, which inserts dorsally into the cephalopharingeal skeleton. Each gland has a monolayer of epithelial cells surrounded by basement membrane and connective tissue. The cellular plasma membrane is enfolded at its base, forming a labyrinthine area. The cell surface is linked to the basement membrane (BM) by hemidesmosomes and to adjacent cells by septet junctions and desmosomes. Irregular channels with several vesicles occur between the cytoplasm and BM. Golgi complex, rough and smooth endoplasmic reticulum, ribosome, lysosomes, multivesicular bodies, and myelin figures are usually present in the cells. The nucleus is large, with diffuse chromatin. The connective tissue circling the BM contains collagen fibrils, muscle fibers and tracheal tubes. Lined cuticle encloses the efferent and deferent ductal cells, which have few, widely dispersed mitochondria, free ribosomes, microtubules, and a large nucleus with diffuse chromatin.

The mesostigmatid genus Andreacarus Radford, 1953 (Acari: Laelapidae), species of which are obligatory parasites of small mammals, is revised. Andreacarus includes 11 species, four species previously recognized and seven new species described from Madagascar hosts: A. brachyuromys sp. n. from Brachyuromys betsileoensis Bartlett, A. eliurus sp. n. from Eliurus species, A. gymnuromys sp. n. from Gymnuromys roberti Major, A. voalavo sp. n. from Voalavo gymnocaudus Carleton & Goodman, A. nesomys sp. n. from Nesomys rufus Peters—all from nesomyid rodents; A. tenrec sp. n. from Tenrec ecaudatus Schreber (Afrosoricida: Tenrecidae); and A. galidia from Galidia elegans I. Geoffroy Saint-Hilaire (Carnivora: Viverridae). An amended generic diagnosis and key to females are also given. Six species described in Andreacarus from Australian and New Guinean hosts are removed and transferred to the new genus, Juxtalaelaps.

Understanding mosquito mating biology is essential for studies of mosquito behavior, gene flow, population structure, and genetic control. In the current study, we examine the effect of age and body size on spermatozoa number in two laboratory strains of the dengue vector, Aedes aegypti (L.), Thailand and Rockefeller (ROCK), and in wild-collected mosquitoes from Thailand. Body size was a major predictor of total spermatozoa number, with significantly greater sperm numbers in large (2.27-mm wing length) versus small males (1.85-mm wing length) within the same age group. Total sperm capacity also varied by male age. Spermatozoa numbers in virgin Ae. aegypti males increased significantly up to 10 d after emergence and then leveled off until 20 d. Significant variations in sperm number were detected among Ae. aegypti strains, with wild-collected mosquitoes having the greatest total number of sperm. Our study provides the first evidence of spermatogenesis in adult mosquitoes and indicates high rates of spermatogenesis in male mosquitoes up to 10 d of age (3.3 degree-days). Our results emphasize the potential role of body size and age on the mating capacity of this important vector of dengue and yellow fever viruses.

The behavioral responses of Aedes aegypti (L.) and Aedes albopictus (Skuse) adults to several attractive cues, as reactions to mosquito traps, are compared in the laboratory, and differences in the primary attractive factors for both species are discussed. Target-attacking frequency of unfed Ae. aegypti females was >30 times that of unfed Ae. albopictus females under simulated conditions. Changes in the percentage of trapped mosquitoes under several attractive conditions using commercial mosquito traps showed that Ae. aegypti mosquitoes were trapped 2–3 times faster than Ae. albopictus. For Ae. aegypti, the combination of a visual cue CO₂ alone enhanced attractiveness, whereas both a visual cue CO₂ as well as a visual cue octenol enhanced Ae. albopictus. The combination of at least three factors, such as a visual cue, CO₂, and a chemical cue is thought to be valuable for trapping and estimating the relative adult population sizes of Ae. aegypti and Ae. albopictus in the field.

Seasonal variations of insect population sizes are often dramatic, particularly in temperate regions and at altitudes where the climatic conditions are unfavorable to insect development during the winter. Decline of population size (or bottlenecks) and founder events may reduce the genetic variability and may create genetic differentiation between populations by drift and founder effects, but this reduction of genetic diversity is strongly influenced by gene flow between populations. In this study, we determined the population genetic structure for two stomoxyine species (Diptera: Muscidae), Stomoxys calcitrans (L.) and Stomoxys niger niger Macquart, which co-occur in dairy barns along an altitudinal gradient on La Réunion island. Using microsatellite markers, we quantified the genetic variation within and among populations for different altitudes. This study displays that, contrary to expectations, genetic diversity is not correlated with altitude and that genetic differentiation is not larger among high-altitude populations than among low-altitude populations. These results attest to the small drift and founder effects in high-altitude populations despite drastic decreases in population size during the winter. Furthermore, at the island scale, the populations of S. calcitrans were slightly differentiated, but those of S. niger niger were not. Together, the results revealed large levels of gene flow on La Réunion Island despite the dramatic geographic barriers, and they emphasize the importance of considering agricultural practices to restrict the dispersal of stomoxyines.

The Hylesia genus comprises a group of Neotropical moths ubiquitous in the Americas from Arizona to Argentina. One of the species of the Hylesia genus in Venezuela, French Guyana, and Trinidad has been identified as Hylesia metabus (Cramer 1775) (Lepidoptera: Saturniidae). In Venezuela, these moths are found in abundance in the mangrove (Avicennia spp.) swamps surrounding the Gulf of Paria and the Orinoco Delta in the eastern part of the country. During the mating season, the female adults shed copious amounts of urticating setae in the air, producing a severe papulovesicular dermatitis among the population in the affected areas. The females also use their urticating setae to protect the eggs during the hatching period. In the current study, we have isolated and partially characterized proteins with proinflammatory properties from the urticating setae in the egg-nests by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and anionic exchange-high-performance liquid chromatography (HPLC). We also have studied the biological response of the egg-nest extract and the HPLC purified fractions by inoculation in guinea pigs; and, analyzing the tissue samples by means of histopathological methods. The results of this study show that the extracted venom and HPLC purified subcomponents give rise to an intense inflammatory reaction characterized by massive infiltration of inflammatory cells, echymoses, and vascular degeneration. Chromatographic separation showed that the venom was made up of proteins having selectively vasodegenerative-fibrinolytic or proinflammatory-quimotactic properties.

Gas chromatography-mass spectrometry was used to analyze the cuticular hydrocarbons extracted from the pupal exuviae of six necrophagous flies: Aldrichina grahami (Aldrich), Chrysomya megacephala (F.), Lucilia sericata (Meigen), Achoetandrus rufifacies (Macquart), Boettcherisca peregrina (Robineau-Desvoidy), and Parasarcophaga crassipalpis (Macquart). A discriminant model including the variables of peak 1 (tricosane), peak 7 (9-,11-,13-methyl-pentacosane), peak 21 (11,12-;9,13-dimethyl-hexacosane), peak 24 (octocosane), peak 41 (7,11-dimethyl-nonacosane), peak 42 (3-methyl-nonacosane), peak 46 (2-methyl-hentriacontane), and peak 51 (unknown) was constructed, which allowed a complete separation of the pupal exuviae of the six species. These results indicate that cuticular hydrocarbons as chemotaxonomic characters for insects of forensic importance are of high value and feasibility.

Studies were carried out in Manitoba, Canada, to evaluate the efficacy of three repellent products for protection of human subjects against mosquito bites. All test substances contained the active ingredient N,N-diethyl-3-methylbenzamide (deet); two were polymer-based creams (3M Ultrathon Insect Repellent and Morflex DEET Insect Repellent 30) and the third (Muskol Insect Repellent) was an alcohol-based pump spray formulation. Application of repellent was to the forearm and lower legs of subjects at 0.75 or 0.83 mg deet/cm². Exposure to mosquito attack was continuous, and efficacy was determined by measuring complete protection time (CPT). Regardless of whether delivered as a polymer cream or in alcohol, mean CPT was similar for the tested repellents at 623 ± 107 to 644 ± 163 min. By contrast, mean CPT for the different test subjects showed significant variation, ranging from 531 ± 42 to 756 ± 54 min. Mosquito collections from untreated human test subjects, Centers for Disease Control and Prevention (CDC) light traps and sweep-netting consisted primarily of Ochlerotatus sticticus (Meigen) and Aedes vexans (Meigen). Relative catch of these two species was similar for different sampling methods through much of the day, but not in the evening, when CDC light traps oversampled Ae. vexans relative to untreated human subjects. Results are used to highlight the need to account for intersubject variation when designing repellent studies, and also are used as a basis to discuss limitations associated with using relatively few subjects when testing repellents.

Insecticide resistance owing to insensitive acetylcholinesterase (AChE)1 has been reported in several mosquito species, and only two mutations in the ace-1 gene have been implicated in resistance: 119S and 331W substitutions. We analyzed the AChE1 resistance status of Culex vishnui (Theobald) and Culex tritaeniorhynchus Giles sampled in various regions of China. These two species displayed distinct mutations leading to AChE1 insensitivity; the 119S substitution in resistant C. vishnui mosquitoes and the 331W substitution in resistant C. tritaeniorhynchus. A biochemical test was validated to detect the 331W mutation in field samples. The comparison of the recombinant G119S and 331W mutant proteins produced in vitro with the AChE1 extracted from resistant mosquitoes indicated that the AChE1 insensitivity observed could be specifically attributed to these substitutions. Comparison of their biochemical characteristics indicated that the resistance conferred by these mutations depends on the insecticide used, regardless of its class. This resistance seemed to be fixed in the Cx. tritaeniorhynchus populations sampled in a 2,000-km transect, suggesting a very high level of insecticide application or a low fitness cost associated with this 331W mutation.

Increased threat of mosquito-borne disease coupled with decreased tolerance of nuisance mosquitoes has opened a market for pest management professionals to offer mosquito control services for homeowners. A pest management professional applied bifenthrin (0.08%) and lambda-cyhalothrin (0.1%) at their maximum label concentrations as barrier treatments. We tested treatments residual efficacy in reducing adult mosquito populations and compared these chemicals against a water control at 24 residential properties (eight replications by three treatments). Mosquito populations were measured on each property by using five methods: CO₂-baited Centers for Disease Control (CDC) light traps (without a light), human landing rates, CDC gravid traps, ovitraps, and sweep nets. Populations were monitored weekly for 2 wk before treatment and 8 wk posttreatment. Additionally, to confirm residual efficacy of each insecticide, a randomly treated leaf underwent a no-choice bioassay with laboratory-reared Aedes albopictus (Skuse). Trap collections were dominantly Aedes albopictus and Culex pipiens L. Both insecticidal treatments significantly reduced Aedes spp. lambda-Cyhalothrin- and bifenthrin-treated sites had 89.5 and 85.1% fewer Ae. albopictus bites than the untreated control, respectively. Ae. albopictus bioassay results showed significant residual efficacy for both insecticides up to 6 wk posttreatment. There were no significant differences between properties treated with the two insecticides. In contrast, Culex spp. were not reduced by either insecticidal treatment. Our study indicated that barrier sprays applied to low-lying vegetation do not properly target adult daytime resting sites for Culex mosquitoes but that they can reduce Aedes mosquitoes. Perhaps by treating upper tree canopies Culex spp. abundance may be reduced.

Amblyomma americanum (L.), the lone star tick, is an aggressive ixodid tick that has been implicated as a vector for several bacteria. Among these bacteria are the disease agents Ehrlichia chaffeensis and Ehrlichia ewingii, and the putative disease agent “Borrelia lonestari.” The hypothesis in this study was that wild lone star ticks from northeastern Georgia are capable of transmitting all three agents to white-tailed deer, Odocoileus virginianus, a known reservoir host for E. chaffeensis. In this study, transmission of all three agents from wild caught lone star ticks to captive reared white-tailed deer was demonstrated by polymerase chain reaction (PCR), culture, or serology. Two of three deer showed evidence of E. chaffeensis and E. ewingii infection by polymerase chain reaction assay; all three deer showed evidence of B. lonestari by PCR assay. E. chaffeensis was isolated in culture from both PCR-positive deer on multiple days. All three deer seroconverted to E. chaffeensis, whereas one deer seroconverted to B. lonestari. This study supports the role of lone star ticks and white-tailed deer as a vector and reservoir host for E. chaffeensis and E. ewingii and suggests for the first time, transmission of B. lonestari from lone star ticks to white-tailed deer.

Before the eradication of Boophilus ticks from the United States, Rhipicephalus (Boophilus) microplus (Canestrini) and Rhipicephalus (Boophilus) annulatus (Say) were important biological vectors of the cattle pathogen Anaplasma marginale Theiler. In the absence of Boophilus ticks, A. marginale continues to be transmitted by Dermacentor ticks. However, a few U.S. strains are not transmissible by Dermacentor andersoni Stiles, Dermacentor variabilis (Say), or both, raising the question of how these strains evolved and how they are maintained. We hypothesize that the U.S. non-Dermacentor-transmissible strains of A. marginale were formerly Boophilus-transmitted strains that have been maintained by a combination of persistent infection and mechanical transmission since the eradication of their biological vector from the United States. To test this hypothesis, we attempted to transmit a well-documented non-Dermacentor-transmissible A. marginale strain (Florida), by using D. andersoni and the two Boophilus species that formerly occurred in the United States. For comparison, we examined tick-borne transmission of a strain of A. marginale (Puerto Rico), which has previously been shown to be transmissible by both D. andersoni and B. microplus. All three species of tick transmitted the Puerto Rico strain, and immunohistochemical (IHC) analysis confirmed the presence of A. marginale colonies in their salivary glands. All three tick species failed to transmit the Florida strain. Although both D. andersoni and B. microplus acquired transient midgut and salivary gland infections after acquisition feeding, we were unable to detect colonies of the Florida strain in the salivary glands with IHC. This demonstrates that the transmission phenotype of A. marginale strains is conserved among tick species, and it suggests that the failure of the Florida strain to be transmitted by ticks is related to a general inability to efficiently invade or replicate in tick cells, rather than to a failure to invade or replicate in cells of a specific tick species.

Survival and replication of dengue-2 virus (family Flaviviridae, genus Flavivirus, DENV-2) was determined in diapausing eggs of Aedes albopictus (Skuse) (Diptera: Culicidae) to evaluate the importance of this mechanism for viral maintenance during adverse climatic conditions. Infected and uninfected eggs of Ae. albopictus were induced to diapause under low temperature and short photoperiod. Virus was detected by reverse transcription-polymerase chain reaction and isolated in C6/36 cells from both diapausing eggs and nondiapausing eggs. Nucleic acid hybridization was used to monitor viral replication in diapausing eggs. DENV-2 might survive in infected diapausing eggs in a relatively quiescent status based on the absence of a replicative intermediate RNA. In contrast, the viral replicative intermediate RNA along with the replicative form RNA was detected in nondiapausing eggs. It seemed that the virus replicated more actively in nondiapausing eggs than in diapausing eggs. Infected diapausing eggs may play an important role in the maintenance of DENV during adverse climatic conditions in nature.

The effectiveness of long-lasting preimpregnated nets of Permanet type (deltamethrin, 50 mg/m²) erected in households in rural areas of Côte d’Ivoire was tested on two laboratory strains of Anopheles gambiae s.s.: the Kisumu susceptible strain and the Vk per pyrethroids resistant strain with >70% kdr allelic frequency. Treated nets were distributed in households in three villages of Danané forest area in western part of Côte d’Ivoire. In each village, a net was sampled for bioassays. Three Permanets also were erected in the laboratory, serving as control samples. From May 2001 to July 2002, the effectiveness of these deltamethrin-pretreated nets was monitored using World Health Organization-cone tests on the two strains of An. gambiae. Mortality rates were recorded 24 h postexposure. Knockdown times for 50 and 95% mosquitoes (kdT₅₀ and kdT₉₅, respectively) were estimated by means of WIN DL software. One-way analysis of variance was used to compare the knockdown times. Times to failure of nets were analyzed using Cox model. The kdT₅₀ of the Kisumu susceptible strain with both laboratory samples and nets used in the field varied around 10 min. No significant difference was recorded between the kdT₅₀ of the Kisumu susceptible strain with laboratory kept nets and samples of nets used in the field. The kdT₉₅ values were in the same scale with the two types of nets. The kdT₅₀ of the Vk per resistant strain when exposed to used nets were twofold that of the Kisumu susceptible strain at the beginning of the trial, and they increased to fivefold 15 mo later. These latter kdT₅₀ significantly differed to those of the Kisumu susceptible strain tested with laboratory and field samples of nets. The kdT₉₅ significantly differed from those of the Kisumu strain with laboratory kept nets and with field kept nets. Baseline bioassay mortality rates were always 99–100% with the Kisumu susceptible strain, and they did not show any significant difference between laboratory-kept nets and field-used nets during the 15-mo trial. With the Vk per resistant strain, the expected long-lasting activity was not achieved. A high decrease of mortality rates was observed from 69 to 75% in the first 3 mo to 2% at the month 15. This mortality was associated with significant differences between Vk per resistant strain tested with field-used nets compared with Kisumu susceptible strain tested with both laboratory kept-nets and field-used nets. This study emphasized the actual long-lasting effectiveness of Permanet against the An. gambiae Kisumu susceptible reference strain and a rapid decrease of residual activity against a strain with kdr-based resistance to pyrethroids.

Field studies were conducted in a rice, Oryza sativa L., agroecosystem in Mwea Kenya to compare the efficiency of CO₂-baited Centers for Disease Control (CDC) light traps against nonbaited CDC light traps and gravid traps against oviposition traps in outdoor collection of Culex quinquefasciatus Say (Diptera: Culicidae) and other mosquitoes. Collectively, 21 mosquito species from the genera Culex, Anopheles, Mansonia, Ficalbia, and Aedes were captured during the 10-wk study period. Cx. quinquefasciatus was the predominant species in all trap types with proportions ranging from 57% in the nonbaited CDC light traps to 95% in the gravid traps. Significantly higher numbers of Cx. quinquefasciatus and Culex annulioris Theobald were collected in the CO₂-baited CDC light traps than in the nonbaited CDC light traps, but the numbers of other mosquito species, including malaria vectors Anopheles arabiensis Patton and Anopheles funestus Giles did not differ significantly between the two trap types. More Cx. quinquefasciatus females were collected in grass infusion-baited gravid traps than egg rafts of this species in oviposition traps containing the same infusion. Although most mosquitoes captured in CO₂-baited and nonbaited CDC light traps were unfed, most of those collected in gravid traps were gravid. From these findings, it is concluded that at least in the rice-growing area of Mwea Kenya, CO₂-baited CDC light traps in conjunction with gravid traps can be used in monitoring of Cx. quinquefasciatus both for control and disease surveillance.

A study to determine the relative abundance and seasonality of forensically important blow flies (Diptera: Calliphoridae) in rural north-central Florida was conducted using pig carcasses (Sus scrofa L.) as models for human bodies. Seven species of Calliphoridae were collected: Lucilia coeruleiviridis (=Phaenicia) (Macquart), Cochliomyia macellaria (F.), Chrysomya rufifaces (Macquart), Phormia regina (Meigen), Chrysomya megacephala (F.), and a few specimens of Calliphora livida Hall, and Calliphora vicina Robineau-Desvoidy. Species composition in aerial collections of adult flies, preserved larval collections, and samples of larvae reared to the adult stage were all highly correlated. Relative abundance of the species found was significantly different, with L. coeruleiviridis the most abundant species year-round. The relative abundance of the collected species varied significantly by day of decomposition and by season, with significant interactions between season and day, season and species, and day and species. L. coeruleiviridis, C. macellaria, C. rufifaces, and P. regina were found during the entire year, two C. vicina specimens and 11 C. livida specimens were collected from December to March, whereas C. megacephala was collected only from June through September.

The growth and development of carrion-feeding calliphorid (Diptera: Calliphoridae) larvae, or maggots, is of great interest to forensic sciences, especially for estimation of a postmortem interval (PMI). The development rate of calliphorid larvae is influenced by the temperature of their immediate environment. Heat generation in larval feeding aggregations (=maggot masses) is a well-known phenomenon, but it has not been quantitatively described. Calculated development rates that do not include internally generated temperatures will result in overestimation of PMI. Over a period of 2.5 yr, 80 pig, Sus scrofa L., carcasses were placed out at study sites in north central Florida and northwestern Indiana. Once larval aggregations started to form, multiple internal and external temperatures, and weather observations were taken daily or every few days between 1400 and 1800 hours until pupation of the larvae. Volume of each aggregation was determined by measuring surface area and average depth. Live and preserved samples of larvae were taken for species identification. The four most common species collected were Lucilia coeruleiviridis (=Phaenicia) (Macquart) (77%), Cochliomyia macellaria (F.) (8.3%), Chrysomya rufifaces (Macquart) (7.7%), and Phormia regina (Meigen) (5.5%). Statistical analyses showed that 1) volume of a larval mass had a strong influence on its temperature, 2) internal temperatures of masses on the ground were influenced by soil temperature and mass volume, 3) internal temperatures of masses smaller than 20 cm³ were influenced by ambient air temperature and mass volume, and 4) masses larger than 20 cm³ on the carcass had strongly regulated internal temperatures determined only by the volume of the mass, with larger volumes associated with higher temperatures. Nonsignificant factors included presence of rain or clouds, shape of the aggregation, weight of the carcass, species composition of the aggregation, time since death, or season.

The insecticidal constituents of hexane-soluble fraction from a methanolic extract of the seeds from Myristica fragrans (Myristicaceae) against adult females of Blattella germanica (L.) (Dictyoptera: Blattellidae) were analyzed by gas chromatography and gas chromatography-mass spectrometry. The insecticidal activity of 13 Myristica seed compounds against female B. germanica was examined by using the filter-paper contact toxicity and vapor phase toxicity bioassays. Results were compared with those of the other 23 known compounds of Myristica seed and currently used insecticides: dichlorvos, deltamethrin, permethrin, and propoxur. In contact toxicity tests using female B. germanica, (1S)-(−)-β-pinene (0.06 mg/cm²) was the most toxic insecticide, based on 24-h LD₅₀ values. The insecticidal activity of this compound was comparable with that of permethrin (0.05 mg/cm²). (1R)-( )-Camphor, (1S)-(−)-camphor, dipentene, (1R)-( )-β-pinene, and ( )-α-terpineol (0.10–0.14 mg/cm²) were more toxic than propoxur (0.19 mg/cm²). (E)-Sabinene hydrate and propoxur were almost equitoxic. Potent insecticidal activity also was observed with (R)-( )-citronellal, (S)-(−)-citronellal, (R)-(−)-α-phellandrene, (1S)-(−)-α-pinene, (1R)-( )-α-pinene, and safrole (0.27–0.48 mg/cm²). In vapor phase toxicity tests, the compounds tested were effective in closed but not in open containers. These results indicate that the effect of these compounds was largely a result of action in the vapor phase. Myristica seed compounds described merit further study as potential insecticides or as leads for the control of cockroaches.

Plague is a rare but highly virulent flea-borne zoonotic disease caused by the Gram-negative bacterium Yersinia pestis Yersin. Identifying areas at high risk of human exposure to the etiological agent of plague could provide a useful tool for targeting limited public health resources and reduce the likelihood of misdiagnosis by raising awareness of the disease. We created logistic regression models to identify landscape features associated with areas where humans have acquired plague from 1957 to 2004 in the four-corners region of the United States (Arizona, Colorado, New Mexico, and Utah), and we extrapolated those models within a geographical information system to predict where plague cases are likely to occur within the southwestern United States disease focus. The probability of an area being classified as high-risk plague habitat increased with elevation up to ≈2,300 m and declined as elevation increased thereafter, and declined with distance from key habitat types (e.g., southern Rocky Mountain piñon—juniper [Pinus edulis Engelm. and Juniperus spp.], Colorado plateau piñon-juniper woodland, Rocky Mountain ponderosa pine (Pinus ponderosa P.& C. Lawson var. scopulorum), and southern Rocky Mountain juniper woodland and savanna). The overall accuracy of the model was >82%. Our most conservative model predicted that 14.4% of the four-corners region represented a high risk of peridomestic exposure to Y. pestis.

Anopheline species of the subgenus Kerteszia, including Anopheles (Kerteszia) cruzii Dyar & Knab (Diptera: Culicidae), are bromeliad-malaria vectors in the Atlantic rain forest of Brazil. Morphological, genetic, and molecular polymorphisms among different populations of An. cruzii have been reported, and it has been suggested that this taxon includes a complex of cryptic species. Specimens of An. cruzii were collected in the states of São Paulo and Santa Catarina, from locations where autochthonous malaria cases have been reported during the last decade. The second internal transcribed spacers (ITS2) of nuclear ribosomal DNA of the captured specimens were sequenced and compared with each other. Intraspecific ITS2 sequence polymorphisms were identified, and nucleotide divergence among specimens varied from 0.3 to 0.9%. The number of nucleotides in the ITS2 sequences of these mosquitoes varied from 327 to 334, and the CG contents varied from 61.7 to 62%. The data provide further indication of An. cruzii being a complex of cryptic species.