Galvis-Ovallos Fredy, Casanova Claudio, Sevá Anaiá da Paixão, Galati Eunice Aparecida Bianchi
Programa de Pós-Graduação em Saúde Pública, Faculdade de Saúde Pública, Universidade São Paulo - USP, São Paulo, SP, Brazil.
Superintendência de Controle de Endemias, Secretaria de Estado da Saúde, Mogi Guaçu, São Paulo, Brazil.
Parasit Vectors. 2017 May 30;10(1):269. doi: 10.1186/s13071-017-2211-8.
Visceral leishmaniasis (VL) is an important public health challenge in Brazil because of the high number of human and canine cases reported annually. Leishmania infantum is the etiological agent of VL and Lutzomyia longipalpis is its main vector. However, evidence suggests that this taxon constitutes a species complex. In Sao Paulo state, there are two populations of Lu. longipalpis, each secreting distinct pheromones, (S)-9-methylgermacrene-B and Cembrene 1; both have been associated with different patterns of VL transmission. The aim of the present study was to investigate the temporal distribution and natural infection of the (S)-9-methylgermacrene-B population of the Lu. longipalpis complex in a highly VL endemic area of Sao Paulo state to obtain information that may contribute to the surveillance of this zoonosis and to the planning of preventive and control measures.
The study was carried out in Panorama municipality, Sao Paulo State. Captures were made during 24 months in seven domiciles. The relation between sand fly abundance and climatic variables, temperature and humidity, was analyzed and natural infection by Leishmania spp. in sand fly females was investigated by nested PCR.
A total of 4120 sand flies, with predominance of Lu. longipalpis (97.2%) were captured. The highest averages of sand flies/night/trap occurred in the rainy season (November-March) and a positive, significant correlation between sand fly abundance and the temperature and humidity 20 days before the capture days was found. Leishmania infantum DNA was detected in three out of 250 pools of females analyzed, giving an estimated minimum infection rate of 1.2%.
The identification of the climatic association between the high abundance of the vector in this highly endemic VL focus constitutes a fundamental point for evaluating future vector and dog control measures and this information increases the data of VL foci in Sao Paulo state that could contribute to the public health authorities in planning prevention and control measures. The identification of natural infection by Le. infantum in Lu. longipalpis specimens reinforces the importance of entomological surveillance activities in this municipality.
由于巴西每年报告的人类和犬类内脏利什曼病（VL）病例数量众多，VL成为该国一项重大的公共卫生挑战。婴儿利什曼原虫是VL的病原体，长须罗蛉是其主要传播媒介。然而，有证据表明该分类单元构成一个复合种。在圣保罗州，存在两个长须罗蛉种群，每个种群分泌不同的信息素，即（S）-9-甲基大根香叶烯-B和西松烯1；二者均与不同的VL传播模式相关。本研究的目的是调查圣保罗州一个VL高度流行地区的长须罗蛉复合种中（S）-9-甲基大根香叶烯-B种群的时间分布和自然感染情况，以获取有助于监测这种人畜共患病以及规划预防和控制措施的信息。
研究在圣保罗州的帕诺拉马市开展。在7个住所进行了为期24个月的捕获工作。分析了白蛉丰度与气候变量（温度和湿度）之间的关系，并通过巢式PCR研究了雌性白蛉中利什曼原虫属的自然感染情况。
共捕获4120只白蛉，其中长须罗蛉占主导（97.2%）。白蛉/夜/诱捕器的最高平均捕获量出现在雨季（11月至次年3月）；发现捕获日前20天的白蛉丰度与温度和湿度之间存在正相关且具有显著相关性。在分析的250组雌性白蛉中有3组检测到婴儿利什曼原虫DNA，估计最低感染率为1.2%。
在这个VL高度流行疫源地，确定媒介高丰度与气候之间的关联是评估未来媒介和犬类控制措施的一个关键点，这些信息增加了圣保罗州VL疫源地的数据，有助于公共卫生当局规划预防和控制措施。在长须罗蛉标本中鉴定出婴儿利什曼原虫的自然感染情况，强化了该市昆虫学监测活动的重要性。
