Evaluating sampling strategies for enzootic Venezuelan equine encephalitis virus vectors in Florida and Panama.

Determining effective sampling methods for mosquitoes are among the first objectives in elucidating transmission cycles of vector-borne zoonotic disease, as the effectiveness of sampling methods can differ based on species, location, and physiological state. The Spissipes section of the subgenus Melanoconion of Culex represents an understudied group of mosquitoes which transmit Venezuelan equine encephalitis viruses (VEEV) in the Western Hemisphere. The objective of this study was to determine effective collection methods that target both blood-engorged and non-engorged females of the Spissipes section of Culex subgenus Melanoconion to test the hypothesis that favorable trapping methods differ between species and by physiological status within a species. Mosquitoes were collected using two commercially available traps, (CDC-light trap and BG-Sentinel trap), two novel passive traps (a novel mosquito drift fence and pop-up resting shelters), and two novel aspirators, (a small-diameter aspirator and a large-diameter aspirator) in Darién, Panama, and Florida, USA. The total number of female mosquitoes collected for each species was compared using rarefaction curves and diversity metrics. We also compared the utility of each trap for collecting total females and blood-engorged females of four Spissipes section mosquito species in Florida and Darién. In Darién, it was found that both blood-engorged and unfed females of Cx. pedroi were most effectively collected using the mosquito drift fence at 57.6% and 61.7% respectively. In contrast, the most unfed Cx. spissipes were collected using the mosquito drift fence (40.7%) while blood-engorged females were collected effectively by pop-up resting shelters (42.3%). In Florida, the best sampling technique for the collection of blood-engorged Cx. panocossa was the large diameter aspirator at 41.9%, while the best trap for collecting Cx. cedecei was the pop-up resting shelter at 45.9%. For unfed female Spissipes section mosquitoes in Florida, the CDC light trap with CO2 collected 84.5% and 98.3% of Cx. cedecei and Cx. panocossa respectively in Florida. Rarefaction analysis, and both the Shannon and Simpsons diversity indices all demonstrated that the mosquito drift fence was capable of collecting the greatest diversity of mosquito species regardless of location. The finding that the proportions of unfed and blood-engorged mosquitoes collected by traps differed both among and between species has implications for how studies of VEEV vectors will be carried out in future investigations. In Florida a combination of pop-up resting shelters and use of a large-diameter aspirator would be optimal for the collection of both VEEV vectors for host-use studies. Results demonstrate that traps can be constructed from common materials to collect mosquitoes for VEEV vector studies and could be assessed for their utilization in vectors of other systems as well. Unfortunately, no single method was effective for capturing all species and physiological states, highlighting a particular need for assessing trap utility for target species of a study.

Implementation of bamboo and monkey-pot traps for the sampling cavity-breeding mosquitoes in Darién, Panama.

Despite the importance of Aedes, Haemagogus and Sabethes in the transmission of yellow fever virus (YFV) and the public health impacts of recent YFV epidemics in the Americas, relatively little has been reported on the biology and ecology of these vectors. Many Aedes, Haemagogus and Sabethes spp. in the American tropics inhabit and develop in the forest canopy and are difficult to sample with conventional entomological surveillance methods. We tested the utility of two previously developed phytotelmata-style oviposition traps (bamboo Guadua angustifolia) and (monkey-pot Lecythis minor), for collecting immature forms of these mosquitoes in a forest near the community of Aruza Abajo, Darién Province, Panama. Our results showed distribution of mosquito species emerging from the two types of traps was found to be significantly different (X2 = 210.23; df = 14; P < 0.001), with significantly greater numbers of Sabethes (Peytonulus) aurescens (Lutz) and Sabethes (Peytonulus) undosus (Coquillett) emerging from the bamboo traps. More females of Sabethes (Sabethes) cyaneus (Fabricius) were captured in the monkey-pot traps, although the difference was not significant. No differences were observed in the average time to emergence for the two traps. These results suggest that various phytotelmata-style traps, including monkey-pot and bamboo, could be used to improve entomological surveillance of YFV vectors in the American tropic.

Especies Crípticas Lutzomyia longipalpis (Diptera: Phlebotominae) y sus Implicaciones en la Transmisión de Leishmaniasis en Panamá / Cryptic Species Lutzomy ia longipalpis (Diptera: Phlebotominae) and its Implications in the Transmission of Leishmaniasis in Panama

Lutzomyia longipalpis es el principal v ector de una importante enfermedad desatendida en América. La diversidad genética de este vector se estimó en la población colectada en dos áreas geográficas separadas por hasta 37 km. Analizamos la secuencia CB3­PDR / N1N­PDR de 22 individuos obte­ niendo un parámetro de: h = 0.43 y π = 0.0017 (Bona), h = 0.89, π = 0.004 (El Limón) con una dife­ renciación genética de kst = 0.03; p> 0.05 entre ellos. Ocho haplotipos fueron detectados, de los cuales fue compartido. Se detectó una diferenciación significativa entre las poblaciones Panamá­ Colombia (kst = 0.98), Panamá­Costa Rica (kst = 0.98) y Panamá­Brasil (kst = 0.72) bajo el modelo de aislamiento. Las inferencias genéticas de esta población pueden complementar la información de la capacidad de dispersión y brindar pistas importantes para comprender la ecología de Lutzom­yia longipalpisen Panamá.

Lutzomyia longipalpis is the main vector of an important neglected disease in America. The genetic div ers ity of this vector was estimated in the population collected in two geographical areas separated by up to 37 km. We analyzed the sequence CB3­PDR / N1N­PDR of 22 individuals obtaining a parameter of: h = 0.43 and π = 0.0017 (Bona), h = 0.89, π = 0.004 (The Lemon) with a genetic differentiation of kst = 0.03; p> 0.05 between them. Eight haplotypes were detected, of which it was shared. A significant differentiation was detected between the Panama­Colombia (ks t = 0.98), Panama­Costa Rica (kst = 0.98) and Panama­Brazil (kst = 0.72) populations under the isolation model. The genetic inferences of this population can complement the dispersion information and provide important clues to understand the ecology of Lutzomyia longipalpis in Panama.