Discovery of filarial nematode DNA in Amblyomma americanum in Northern Virginia.

Ticks collected in 2011 were screened for the presence of filarial nematode genetic material, and positive samples were sequenced for analysis. Monanema-like filarial nematode DNA was recently discovered in Amblyomma americanum in northern Virginia, marking the first time genetic material from this parasite has been discovered in ticks in the state. Phylogenetic analysis revealed that this material was directly related to a previously discovered filarial nematode in A. americanum populations in Maryland as well as recently identified parasites in Ixodes scapularis from southern Connecticut. Further study is warranted to visually confirm the presence of these nematodes, characterize their distribution, and determine if these ticks are intermediate hosts.

Spotted fever group rickettsiae in multiple hard tick species from Fairfax County, Virginia.

Spotted fever group rickettsiosis (SFGR) is a potentially fatal disease that has displayed increasing incidence in the United States in recent years. The most well-known and severe type of this disease is Rocky Mountain spotted fever, but there are other mild forms that occur. Recently, human infection with Rickettsia parkeri has been reported and linked with the tick Amblyomma maculatum. In 2010, a population of R. parkeri-infected A. maculatum was discovered in Fairfax County, Virginia, leading to increased surveillance of tick species. In this study, we report the presence of R. parkeri in Rhipicephalus sanguineus, Haemaphysalis leporispalustris, and Dermacentor variabilis in Fairfax County. R. parkeri was discovered in two Rh. sanguineus, one H. leporispalustris, and 17 D. variabilis. These findings suggest that spillover infections of R. parkeri may be occurring in tick species not typically associated with this pathogen; however, vector competence studies need to be conducted to determine if these tick species can serve as potential vectors for human SFGR.

Distinct variation in vector competence among nine field populations of Aedes aegypti from a Brazilian dengue-endemic risk city.

BACKGROUND: In Brazil, dengue epidemics erupt sporadically throughout the country and it is unclear if outbreaks may initiate a sustainable transmission cycle. There are few studies evaluating the ability of Brazilian Aedes aegypti populations to transmit dengue virus (DENV). The aim of this study was to compare DENV susceptibility of field-captured Ae. aegypti populations from nine distinct geographic areas of the city of Belo Horizonte in 2009 and 2011. Infection Rate (IR), Vector Competence (VC) and Disseminated Infection Rate (DIR) were determined. METHODS: Aedes aegypti eggs from each region were collected and reared separately in an insectary. Adult females were experimentally infected with DENV-2 and the virus was detected by qPCR in body and head samples. Data were analyzed with the Statistical Package for the Social Sciences version 17. RESULTS: IR varied from 40.0% to 82.5% in 2009 and 60.0% to 100.0% in 2011. VC ranged from 25.0% to 77.5% in 2009 and 25.0% to 80.0% in 2011. DIR oscillated from 68.7% to 100.0% in 2009 and 38.4% to 86.8 in 2011. When the results were evaluated by a logistic model using IR as covariate, North, Barreiro, South-Central and Venda Nova showed the strongest association in 2009. In 2011, a similar association was observed for South-Central, Venda Nova, West and Northeast regions. Using VC as covariate, South-Central and Venda Nova showed the most relevant association in 2009. In 2011, South-Central, Venda Nova and Barreiro presented the greatest revelation associations. When DIR data were analyzed by logistic regression models, Pampulha, South-Central, Venda Nova, West, Northeast and East (2009) as well as South-Central, Venda Nova and West (2011) were the districts showing the strongest associations. CONCLUSIONS: We conclude that Ae. aegypti populations from Belo Horizonte exhibit wide variation in vector competence to transmit dengue. Therefore, vector control strategies should be adapted to the available data for each region. Further analysis should be conducted to better understand the reasons for this large variability in vector competence and how these parameters correlate with epidemiological findings in subsequent years.

Detection of Rickettsia massiliae in Rhipicephalus sanguineus from the eastern United States.

We report the first evidence of Rickettsia massiliae in the brown dog tick, Rhipicephalus sanguineus, from the East Coast of the United States. As part of routine pathogen surveillance, DNA samples from ixodid ticks were tested for spotted fever group rickettsiae by nested PCR. A R. massiliae-positive tick was collected off a beagle mix recently rescued from North Carolina. Infection was confirmed by partial sequence analysis of the htrA, gltA, ompB, ompA, and sca4 genes, which had 100% identity to a R. massiliae isolate from Arizona.

Community ecology of container mosquitoes (Diptera: Culicidae) in Virginia following invasion by Aedes japonicus.

The success of an invasive species in a new region depends on its interactions with ecologically similar resident species. Invasions by disease vector mosquitoes are important as they may have ecological and epidemiological consequences. Potential interactions of a recent invasive mosquito, Aedes japonicus Theobald, with resident species in Virginia were evaluated by sampling larvae from containers and trapping adults. Distinct species compositions were observed for artificial containers and rock pools, with Ae. albopictus most abundant in the former and Ae. japonicus in the latter. However, these two species were found to co-occur in 21.2% of containers sampled. Among the six mosquito species most common in containers from May through September, 2006, only interspecific associations of Ae. japonicus with Aedes albopictus (Skuse) and Aedes triseriatus (Say) were significant, and both were negative. In addition to differences in habitat preference, mean crowding estimates suggest that interspecific repulsion may contribute to the significant negative associations observed between these species. High relative abundances of late instars and pupae of Ae. japonicus seem to provide this species with a mechanism of evading competition with Ae. albopictus, facilitating their coexistence in artificial containers. Although annual fluctuations were observed, trends in adult populations over a 6-yr period provide no evidence of declines. In summary, this survey of diverse container types and all life stages provided only limited evidence for competitive displacements or reductions of resident container species by Ae. japonicus, as observed elsewhere in its invasive range.

High rates of Rickettsia parkeri infection in Gulf Coast ticks (Amblyomma maculatum) and identification of "Candidatus Rickettsia andeanae" from Fairfax County, Virginia.

The Gulf Coast tick, Amblyomma maculatum, is a vector of Rickettsia parkeri, a recently identified human pathogen that causes a disease with clinical symptoms that resemble a mild form of Rocky Mountain spotted fever. Because the prevalence of R. parkeri infection in geographically distinct populations of A. maculatum is not fully understood, A. maculatum specimens collected as part of a tick and pathogen surveillance system in Fairfax County, Virginia, were screened to determine pathogen infection rates. Overall, R. parkeri was found in 41.4% of the A. maculatum that were screened. Additionally, the novel spotted fever group Rickettsia sp., tentatively named "Candidatus Rickettsia andeanae," was observed for the first time in Virginia.

The efficacy of the BG-Sentinel CO2 nozzle in collecting host-seeking mosquitoes in Fairfax County, Virginia.

This study determined whether the addition of a CO2 nozzle made specifically for the BG-Sentinel trap increased the efficacy of collecting host-seeking mosquitoes, particularly Aedes albopictus and Culex spp., which includes Cx. pipiens, Cx. restuans, and occasionally Cx. salinarius in Fairfax County, VA. Twenty BG-Sentinel traps were incorporated into the Fairfax County West Nile virus (WNV) surveillance program: 10 traps were randomly selected each week to have the nozzle attached, and the remaining 10 traps were without the nozzle. The BG-Sentinel traps collected 20 mosquito species with the nozzle and 19 mosquito species without the nozzle. The traps with the nozzle collected 46.58 (SE 3.236) mosquitoes per 24-h trap-period and the traps without the nozzle collected 46.73 (SE 2.942) mosquitoes per 24-h trap-period, and no significant difference (P > 0.05) was found. There was no significant difference (P > 0.05) in the collection of Aedes albopictus, Culex spp., Anopheles punctipennis, Ae. vexans, and Aedes triseriatus between the traps with or without the nozzle. Other mosquito species were collected in low numbers and statistical analysis was not performed. Both the traps with and without the nozzle collected WNV-infected Aedes albopictus and Culex spp.

The Zumba mosquito trap and BG-Sentinel trap: novel surveillance tools for host-seeking mosquitoes.

In a periurban habitat located in Northern Virginia, this study used 13 replicates of a 4 x 4 Latin square to evaluate the efficacy of 2 novel mosquito traps, the Zumba mosquito trap and the BG-Sentinel trap, against 2 existing host-seeking mosquito traps [Centers for Disease Control and Prevention (CDC) miniature light and CDC Fay-Prince]. All traps were baited with the BG-Lure and CO2. The Zumba trap, baited with the BG-Lure and CO2 (Zumba trap combination) was the most productive and diverse trap, averaging 35.51 mosquitoes and 4.16 species per trapping period. It collected 19 times as many Culexpipiens/restuans, which will be referred to as Cx. pip/res, as the other traps and was the only trap to collect West Nile virus (WNV)-infected host-seeking Cx. pip/res in the study area. The BG-Sentinel trap, baited with the BG-Lure and CO2 (BG-Sentinel trap combination) collected 7 times as many female Aedes albopictus as the CDC miniature light or Fay-Prince traps. The Zumba trap combination collected 4 times as many female Ae. albopictus as the CDC miniature light or Fay-Prince traps. The WNV infection rate of Cx. pip/res and Ae. albopictus collected by the Zumba trap combination was consistently greater than the infection rates for these species collected in the Fairfax County program's routine CDC miniature light traps and comparable to the infection rate found in the Cx. pip/res collected in the program's routine gravid traps. Both the Zumba and BG-Sentinel trap combinations collected WNV-infected Ae. albopictus in the study area.

Field comparison of novel and gold standard traps for collecting Aedes albopictus in Northern Virginia.

Aedes albopictus is a potential West Nile virus bridge vector in Northern Virginia; however, information regarding its virus transmission dynamics is limited, as this species is not readily collected in existing traps. This study used 5 replicates of a 5 x 5 Latin square to evaluate the efficiency and effectiveness of 2 novel host-seeking mosquito traps (the BG-Sentinel and the Collapsible Mosquito Trap (CMT-20) in collecting Ae. albopictus, relative to a carbon dioxide (CO2)-baited Centers for Disease Control and Prevention (CDC) miniature light trap. When used with CO2, the BG-Sentinel (with BG-Lure) collected 33 times more female Ae. albopictus per 24-h trapping period than did the CO2-baited CDC light trap. Without CO2, the BG-Sentinel (with BG-Lure) still collected over 6 times as many female Ae. albopictus as the CO2-baited CDC trap. Both configurations of the BG-Sentinel were significantly more effective than the other traps. The BG-Sentinel was also significantly more efficient in collecting Ae. albopictus and collected a high proportion of this species, both with CO2 and without CO2. The CMT-20 (with SkinLure) collected significantly more Ae. albopictus when used with CO2 than without CO2, but did not collect significantly more Ae. albopictus than the CO2-baited CDC light trap. The proportion of Ae. albopictus collected in the CMT-20 with CO2 and without CO2 did not differ significantly from the proportion of Ae. albopictus collected in the CDC trap.

The presence of Lutzomyia longipalpis in a focus of American visceral leishmaniasis where the only proven vector is Lutzomyia cruzi. Corumbá, Mato Grosso do Sul State.

The present communication reports the presence of Lutzomyia longipalpis in Corumbá, Mato Grosso do Sul, where the principal vector is Lutzomyia cruzi.

The presence of Lutzomyia longipalpis in a focus of American visceral leishmaniasis where the only proven vector is Lutzomyia cruzi. Corumbá, Mato Grosso do Sul State

The present communication reports the presence of Lutzomyia longipalpis in Corumbá, Mato Grosso do Sul, where the principal vector is Lutzomyia cruzi

Field monitoring of Cypermethrin residual effect on the mortality rates of the phlebotomine sand fly Lutzomyia longipalpis in the State of Paraíba, Brazil

In a visceral leishmaniasis endemic locality of northeast of Brazil where all settlements were treated with cypermethrin, a follow-up of Lutzomyia longipalpis populations was carried out by regular collections. The residual effect of the inseticide was studied using biological assays on three different types of walls. The results showed that the inseticides had an effect on intradomiciliar Lu. longipalpis populations limited to two months, and had no significant effect on peridomiciliar vector populations. The mortality rates of the tested sandflies were variable according to the type of wall. The decreasing of the inseticide effect was marked since the 3rd month, and mortality rates were identical whatever the type of wall since the 4th month. Unsufficient residual effect was detected after the 4th month.

Encuesta epidemiologica de histoplasmosis, paracoccidioidomicosis y leishmaniasis mediante pruebas cutaneas / Epidemiological survey of histoplasmosis, paracoccidioidomycosis, and leishmaniasis based on skin tests

In a village in Brazil's Amazonian jungle, skin test with histoplasmin, paracoccidioidin, and leishmanin were given to a group of 400 subjects aged 10 and older, of both sexes, who also responded to a questionnaire on their history of infectious diseases, There was a high prevalence of positive results in the three tests. The pattern of the results supports the hypothesis that testing with two mycotic antigens does not produce cross-reactions in asymptomatic subjects and that the sources of exposure to the fungi are probably independent. The positive reaction to leishmanin in males was related to farming activities, hunting, fishing, and the collection of firewood; the reactions in females showed a limited correlation with fishing and a much stronger one with the collection of firewood. With the mycotic antigens, the positive reactions were no associated with any of these activities. There was a high correlation of results using a leishmanin obtained from Leishmania Mexicana amazonensis and a combined leishmanin obtained from Leishmania mexicana and Leishmania brasiliensis. The diameter of induration was generally larger for the latter of these antigens, which induced some very intense responses. The frequency distribution of the magnitude of reaction was heterogeneous in subjects with positive reactions to both leishmanin and paracoccidioidin. Evidence that these findings are consistent with

Observaciones sobre el parasito leishmania mexicana amazonensis y la infeccion natural que provoca en el flebotomo lutzomyia olmeca nociva / Observations on the parasite leishmania mexicana amazonensis and its natural infection of the sand fly lutzomyia olmeca nociva

In 1984 the authors began a search for vectors of the Leishmania mexicana amazonensis parasite in the Brazilian Amazon city of Manaus by capturing phlebotomines (sandflies) at two periurban collection sites and seeking to isolate the parasite from them. One collection site yielded no positive specimens, but the older yielded 10 sandflies infected with Le m. amazonensis. Six of the positive specimens belonged to the sandfly species Lutzomyia flaviscutellata, and four belonged to the species Lu. olmeca nociva. This is the first time that the latter species has been incriminated as a possible vector of Le. m. amazonensis and the first record of Lu. flaviscutellata being infected with this parasite outside of Para State. The capture of infected phlebotomines at one site but no at another similar nearby site is reminiscent of previous results reported by Lainson and Shaw. Whether or not these results indicate the existence of discrete transmission foci is still unclear