Blood feeding patterns of Nyssomyia intermedia and Nyssomyia neivai (Diptera, Psychodidae) in a cutaneous leishmaniasis endemic area of the Ribeira Valley, State of São Paulo, Brazil

Introduction The aim of this study was to identify the blood feeding sources of Nyssomyia intermedia (Ny. intermedia) and Nyssomyia neivai (Ny. neivai), which are Leishmania vectors and the predominant sandfly species in the Ribeira Valley, State of São Paulo, Brazil, an endemic area for cutaneous leishmaniasis. Methods Specimens were captured monthly between February 2001 and December 2003 on a smallholding and a small farm situated in the Serra district in the Iporanga municipality. The blood meals of 988 engorged females were tested using the avidin-biotin immunoenzymatic enzyme-linked immunosorbent assay (ELISA). Seven blood meal sources were investigated: human, dog, chicken, bovine, pig, horse and rat. Results The results showed that among the females that fed on one or more blood sources, the respective percentages for Ny. intermedia and Ny. neivai, respectively, were as follows: human (23% and 36.8%), pig (47.4% and 26.4%), chicken (25.7% and 36.8%) and dog (3.9% and 0%), and the differences in the blood sources between the two species were statistically significant (p = 0.043). Conclusions Both species had predominant reactivity for one or two blood sources, and few showed reactivity indicating three or four sources. Many different combinations were observed among the females that showed reactivity for more than one source, which indicated their opportunistic habits and eclecticism regarding anthropic environmental conditions.

引言
本研究旨在明确巴西圣保罗州里贝拉谷（皮肤利什曼病流行区）的利什曼原虫传播媒介、当地优势白蛉物种——中间尼斯木白蛉（Nyssomyia intermedia，简称Ny. intermedia）与内伊尼斯木白蛉（Nyssomyia neivai，简称Ny. neivai）的血餐来源。

材料与方法
研究于2001年2月至2003年12月期间，每月在伊波朗加市塞拉地区的一处小农舍与小型农场捕获白蛉标本。采用亲和素-生物素免疫酶促酶联免疫吸附试验（avidin-biotin immunoenzymatic enzyme-linked immunosorbent assay, ELISA）对988只吸血雌性白蛉的血餐进行检测，共检测7类血源：人、犬、鸡、牛、猪、马及大鼠。

结果
结果显示，在取食一种或多种血源的雌性白蛉中，中间尼斯木白蛉与内伊尼斯木白蛉的各血源占比分别为：人（23%与36.8%）、猪（47.4%与26.4%）、鸡（25.7%与36.8%）及犬（3.9%与0%）；两种白蛉的血源偏好差异具有统计学显著性（p=0.043）。

结论
两种白蛉均主要对1种或2种血源产生反应，仅少数个体显示出对3种或4种血源的反应。在对多种血源产生反应的雌性白蛉中，观察到多种不同的组合模式，这表明它们在人类活动环境中具有机会主义取食习性与食性包容性。