Enzootic Arbovirus Surveillance in Forest Habitat and Phylogenetic Characterization of Novel Isolates of Gamboa Virus in Panama

Landscape changes occurring in Panama, a country whose geographic location and climate have historically supported arbovirus transmission, prompted the hypothesis that arbovirus prevalence increases with degradation of tropical forest habitats. Investigations at four variably degraded sites revealed a diverse array of potential mosquito vectors, several of which are known vectors of arbovirus pathogens. Overall, 675 pools consisting of 25,787 mosquitoes and representing 29 species from nine genera (collected at ground and canopy height across all habitats) were screened for cytopathic viruses on Vero cells. We detected four isolates of Gamboa virus (family: Bunyaviridae; genus: Orthobunyavirus) from pools of Aedeomyia squamipennis captured at canopy level in November 2012. Phylogenetic characterization of complete genome sequences shows the new isolates to be closely related to each other with strong evidence of reassortment among the M segment of Panamanian Gamboa isolates and several other viruses of this group. At the site yielding viruses, Soberanía National Park in central Panama, 18 mosquito species were identified, and the predominant taxa included A. squamipennis, Coquillettidia nigricans, and Mansonia titillans.Landscape changes occurring in Panama, a country whose geographic location and climate have historically supported arbovirus transmission, prompted the hypothesis that arbovirus prevalence increases with degradation of tropical forest habitats. Investigations at four variably degraded sites revealed a diverse array of potential mosquito vectors, several of which are known vectors of arbovirus pathogens. Overall, 675 pools consisting of 25,787 mosquitoes and representing 29 species from nine genera (collected at ground and canopy height across all habitats) were screened for cytopathic viruses on Vero cells. We detected four isolates of Gamboa virus (family: Bunyaviridae; genus: Orthobunyavirus) from pools of Aedeomyia squamipennis captured at canopy level in November 2012. Phylogenetic characterization of complete genome sequences shows the new isolates to be closely related to each other with strong evidence of reassortment among the M segment of Panamanian Gamboa isolates and several other viruses of this group. At the site yielding viruses, Soberanía National Park in central Panama, 18 mosquito species were identified, and the predominant taxa included A. squamipennis, Coquillettidia nigricans, and Mansonia titillans

Forest disturbance and vector transmitted diseases in thelowland tropical rainforest of central Panama

objective To explore possible changes in the community attributes of haematophagous insects as afunction of forest disturbance. We compare the patterns of diversity and abundance, plus thebehavioural responses of three epidemiologically distinct vector assemblages across sites depictingvarious levels of forest cover.methods Over a 3-year period, we sampled mosquitoes, sandflies and biting-midges in forestedhabitats of central Panama. We placed CDC light traps in the forest canopy and in the understorey togather blood-seeking females.results We collected 168 405 adult haematophagous dipterans in total, including 26 genera and 86species. Pristine forest settings were always more taxonomically diverse than the disturbed forest sites,confirming that disturbance has a negative impact on species richness. Species of Phlebotominae andCulicoides were mainly classified as climax (i.e. forest specialist) or disturbance-generalist, which tendto decrease in abundance along with rising levels of disturbance. In contrast, a significant portion ofmosquito species, including primary and secondary disease vectors, was classified as colonists (i.e.disturbed-areas specialists), which tend to increase in numbers towards more disturbed forest habitats.At pristine forest, the most prevalent species of Phlebotominae and Culicoides partitioned the verticalniche by being active at the forest canopy or in the understorey; yet this pattern was less clear indisturbed habitats. Most mosquito species were not vertically stratified in their habitat preference.conclusion We posit that entomological risk and related pathogen exposure to humans is higher inpristine forest scenarios for Culicoides and Phlebotominae transmitted diseases, whereas forestdisturbance poses a higher entomological risk for mosquito-borne infections. This suggests that theDilution Effect Hypothesis (DEH) does not apply in tropical rainforests where highly abundant, yetunrecognised insect vectors and neglected zoonotic diseases occur. Comprehensive, community levelentomological surveillance is, therefore, the key for predicting potential disease spill over in scenariosof pristine forest intermixed with anthropogenic habitats. We suggest that changes in forest qualityshould also be considered when assessing arthropod-borne disease transmission risk.objective To explore possible changes in the community attributes of haematophagous insects as afunction of forest disturbance. We compare the patterns of diversity and abundance, plus thebehavioural responses of three epidemiologically distinct vector assemblages across sites depictingvarious levels of forest cover.methods Over a 3-year period, we sampled mosquitoes, sandflies and biting-midges in forestedhabitats of central Panama. We placed CDC light traps in the forest canopy and in the understorey togather blood-seeking females.results We collected 168 405 adult haematophagous dipterans in total, including 26 genera and 86species. Pristine forest settings were always more taxonomically diverse than the disturbed forest sites,confirming that disturbance has a negative impact on species richness. Species of Phlebotominae andCulicoides were mainly classified as climax (i.e. forest specialist) or disturbance-generalist, which tendto decrease in abundance along with rising levels of disturbance. In contrast, a significant portion ofmosquito species, including primary and secondary disease vectors, was classified as colonists (i.e.disturbed-areas specialists), which tend to increase in numbers towards more disturbed forest habitats.At pristine forest, the most prevalent species of Phlebotominae and Culicoides partitioned the verticalniche by being active at the forest canopy or in the understorey; yet this pattern was less clear indisturbed habitats. Most mosquito species were not vertically stratified in their habitat preference.conclusion We posit that entomological risk and related pathogen exposure to humans is higher inpristine forest scenarios for Culicoides and Phlebotominae transmitted diseases, whereas forestdisturbance poses a higher entomological risk for mosquito-borne infections. This suggests that theDilution Effect Hypothesis (DEH) does not apply in tropical rainforests where highly abundant, yetunrecognised insect vectors and neglected zoonotic diseases occur. Comprehensive, community levelentomological surveillance is, therefore, the key for predicting potential disease spill over in scenariosof pristine forest intermixed with anthropogenic habitats. We suggest that changes in forest qualityshould also be considered when assessing arthropod-borne disease transmission risk

Anopheles

Key to the females of Anopheles (Kerteszia) 1 Mesepimeron with 1 long, large and curved (C-shaped) scale-patch that extends ventrally from upper setae............. 2 - Mesepimeron with 1 or 2 small scale-patches.............................................................. 3 2 (1) Proboscis, pedicel, and palpomere 1 with white scales; hindtarsomeres 1 and 2 without apical pale band (from dorsal view) (Fig. 3)....................................................................................... lepidotus - Proboscis, pedicel, and palpomere 1 without white scales; hindtarsomeres 1 and 2 with narrow apical pale band (from dorsal view)....................................................................................... pholidotus 3 (1) Mesepimeron with 1 small scale-patch next to upper setae.................................................... 4 - Mesepimeron with 2 small scale-patches (upper and middle).................................................. 7 4 (3) Abdominal terga II–VII with numerous dark decumbent scales; sterna with few white scales........................... .............................................. boliviensis, gonzalezrinconesi, rollai (currently cannot be separated) - Abdominal terga and sterna without scales (except possibly on VII, VIII and cerci)................................ 5 5 (4) Hindtarsomere 5 entirely white-scaled; wing without pale fringe spot at tip of wing...................... bambusicolus - Hindtarsomere 5 with base dark, apical 0.35–0.60 pale; wing with large pale fringe spot at tip or rarely divided into 2 small pale fringe spots..................................................................................... 6 6 (5) Scutum with white scales on acrostichal area from anterior promontory to near prescutellar setae; hindtarsomeres 2–4 with nar- row white band on distal 0.15–0.5........................................................... auyantepuiensis - Scutum without white scales on acrostichal area; hindtarsomeres 2–4 with broad white band on distal 0.5–0.7....... neivai 7 (3) Hindtarsomeres 2–4 with narrow apical pale band, 0.3 or less length of tarsomeres; hindtarsomere 5 usually entirely dark................................................................................................... bellator - Hindtarsomeres 2–5 with broad apical pale bands, 0.4–0.7 length of tarsomere..................................... 8 8 (7) Scutum with anterior 0.3–0.4 of acrostichal and dorsocentral areas and middle of scutellum with few white scales; vein M entirely or mostly white-scaled basal to level of Cu fork................................................. laneanus - Scutum without pale scales on acrostichal, dorsocentral, and scutellum; vein M with dark scales basal to level of Cu fork … 9 9 (8) Scales on palpomeres 3 and 4 predominately decumbent, those on base of 3 may be slightly erect................. cruzii * - Scales on palpomere 3 covered with slightly erect scales, palpomere 4 with slightly erect to decumbent scales.. homunculus *Published as part of Harrison, Bruce A., Ruiz-Lopez, Freddy, Falero, Guillermo Calderon, Savage, Harry M., Pecor, James E. & Wilkerson, Richard C., 2012, Anopheles (Kerteszia) lepidotus (Diptera: Culicidae), not the malaria vector we thought it was: Revised male and female morphology; larva, pupa, and male genitalia characters; and molecular verification, pp. 1-17 in Zootaxa 3218 on pages 4-5, DOI: 10.5281/zenodo.21134

Potential for north American mosquitoes to transmit rift valley fever virus

The rapid spread of West Nile viral activity across North America since its discovery in 1999 illustrates the potential for an exotic arbovirus to be introduced and widely established across North America. Rift Valley fever virus (RVFV) has been responsible for large outbreaks in Africa that have resulted in hundreds of thousands of human infections and major economic disruption due to loss of livestock and to trade restrictions. However, little is known about the potential for North American mosquitoes to transmit this virus should it be introduced into North America. Therefore, we evaluated selected mosquito species from the southeastern United States for their ability to serve as potential vectors for RVFV. Mosquitoes were fed on adult hamsters inoculated 1 day previously with RVFV. These mosquitoes were tested for infection and ability to transmit RVFV after incubation at 26°C for 721 days. None of the species tested (Aedes taeniorhynchus, Ae. vexans, Culex erraticus, Cx. nigripalpus, Cx. quinquefasciatus, and Cx. salinarius) were efficient vectors after they fed on hamsters with viremias ranging from 104.1 to 106.9 plaque-forming units (PFU)/ml. However, Ae. taeniorhynchus, Ae. vexans, and Cx. erraticus all developed disseminated infections after they fed on hamsters with viremias between 108.5 and 1010.2 PFU/ml, and both Ae. vexans and Cx. erraticus transmitted RVFV by bite. These studies illustrate the need to identify the ability of individual mosquito species to transmit RVFV so that appropriate decisions can be made concerning the application of control measures during an outbreak. © 2008 by The American Mosquito Control Association, Inc