Spatial and Temporal Patterns of Phlebotomine Sand Flies (Diptera: Psychodidae) in a Cutaneous Leishmaniasis Focus in Northern Argentina

Abstract

Phlebotomine sand flies (Diptera: Psychodidae) were captured in an area of Argentina endemic for American cutaneous leishmaniasis (ACL). A total of 44,944 flies were collected during a 130-wk interepidemic period from 1990 through 1993. These sand flies included Lutzomyia neivai (Pinto) (97.8%), Lutzomyia migonei (Franca) (1.2%), Lutzomyia cortelezzii (Brèthes) (0.8%), Lutzomyia shannoni (Dyar) (0.1%), and Lutzomyia punctigeniculata (Floch and Abonnenc) (0.1%). Lutzomyia neivai was more abundant in secondary forests and peridomestic environments associated with human cases than in primary forest or xeric thorn scrub areas. Time series analyses of species densities suggested a bimodal or trimodal annual pattern related to rainfall peaks, a 5-wk reproductive cycle, and peridomestic local populations that were located adjacent to secondary forests. In general, sand fly abundance was correlated with the rainfall of the previous year. Lutzomyia neivai spatial distributions were consistent with ACL incidence patterns during the study and in the recent outbreaks in Argentina. However, Lu. migonei also may be involved in peridomestic transmission. Our results suggest that there is a need for improved, long-term surveillance of sand flies and ACL cases, as well as development of effective intervention strategies.

Phlebotominae sand flies associated with a tegumentary leishmaniasis outbreak, Tucumán Province, Argentina

“…Furthermore, Lu. neivai abundance in time and space is consistent with a metapopulation distribution 23 , so the Escaba reserve and the gallery forest of the dam basin, including the Marapa river, may constitute a source population.…”

“…neivai showed a positive association between an above average rainfall peak, or difference between years, and sand fly abundance during the fall of the following year, the season of highest risk 23 . The time relationship between the rainfall and the cases in this outbreak, was consistent both with the lag between the precipitation and the time of appearance of cases during the fall (Figure 2).…”

Lutzomyia longipalpis abundance in the city of Posadas, northeastern Argentina: variations at different spatial scales

“…Recent studies have suggested that the distribution of Lu. longipalpis is heterogeneous and distributed in "source populations" (Salomón et al 2004) scattered throughout a city in a pattern of high abundance areas (HAA) across a matrix of low abundance areas (LAA), which is consistent with a metapopulation structure (Fernández et al 2010).…”

Hot temperatures can force delayed mosquito outbreaks via sequential changes in Aedes aegypti demographic parameters in autocorrelated environments

“…Similar patterns of association between mosquito abundance and weather fluctuations have been observed in other Aedes spp. (Ho et al 1971;Makiya 1974;Sota et al 1992), culicine (Barker et al 2010;Hayes & Downs 1980;Makiya 1973) and anopheline (Minakawa et al 2002) mosquitoes, as well as other Diptera vectors of disease (Morrison et al 1995;Salomon et al 2004). One of the intriguing patterns in these associations is the emergence of relatively long delays in the association between environmental changes and the occurrence of vector outbreaks.…”