BackgroundAmerican visceral leishmaniasis (AVL) is an emerging disease in the state of São Paulo, Brazil. Its geographical expansion and the increase in the number of human cases has been linked to dispersion of Lutzomyia longipalpis into urban areas. To produce more accurate risk maps we investigated the geographic distribution and routes of expansion of the disease as well as chemotype populations of the vector.Methodology/Principal FindingsA database, containing the annual records of municipalities which had notified human and canine AVL cases as well as the presence of the vector, was compiled. The chemotypes of L. longipalpis populations from municipalities in different regions of São Paulo State were determined by Coupled Gas Chromatography – Mass Spectrometry. From 1997 to June 2014, L. longipalpis has been reported in 166 municipalities, 148 of them in the Western region. A total of 106 municipalities were identified with transmission and 99 were located in the Western region, where all 2,204 autochthonous human cases occurred. Both the vector and the occurrence of human cases have expanded in a South-easterly direction, from the Western to central region, and from there, a further expansion to the North and the South. The (S)-9-methylgermacrene-B population of L. longipalpis is widely distributed in the Western region and the cembrene-1 population is restricted to the Eastern region.Conclusion/SignificanceThe maps in the present study show that there are two distinct epidemiological patterns of AVL in São Paulo State and that the expansion of human and canine AVL cases through the Western region has followed the same dispersion route of only one of the two species of the L. longipalpis complex, (S)-9-methylgermacrene-B. Entomological vigilance based on the routes of dispersion and identification of the chemotype population could be used to identify at-risk areas and consequently define the priorities for control measures.

The dispersal pattern of the sand fly Lutzomyia neivai was studied through mark-release-recapture experiments in an American cutaneous leishmaniasis endemic rural area in Southeastern Brazil. Over 6500 specimens were marked with fluorescent powder and released in forest edge and peridomicile habitats from August to November 1999, February and April 2000. Recapture attempts were made using Shannon and CDC traps up Key words: mark-release-recapture -dispersal -sand fly -Lutzomyia neivai -Brazil Information on the dispersion pattern of sand flies vectors in nature can be used to evaluate the potential rate of Leishmania dissemination and to implement surveillance and control strategies against these vectors.Previous dispersal studies have shown that species from Old World arid and semi-arid regions may fly more than 1500 m (Killick-Kendrick et al. 1984, Doha et al. 1991, while sand flies from Neotropical forests seldom travel no more than 200 m from their release point (Chaniotis et al. 1974, Alexander 1987, Alexander & Young 1992, Morrison et al. 1993.In Brazil, the Lutzomyia longipalpis (Lutz & Neiva) dispersal patterns have been studied (Dye et al. 1991, Kelly & Dye 1997, but there is no study of the dispersal pattern of the vectors of American cutaneous leishmaniasis (ACL). In the Southeastern region of Brazil, the forest seems to be the environment of the enzootic cycle of Leishmania (Viannia) braziliensis (Gomes et al. 1989, Gomes 1994, Lainson et al. 1994, and it is mostly in the domiciliary habitat that man becomes infected (Rangel et al. 1990, Gomes 1994, Tolezano 1994, Gontijo et al. 2002. Thus the flight range and the dispersion of sand flies between these habitats are important factors in ACL transmission.The present study was carried out to describe the dispersal pattern of Lutzomyia neivai (Pinto, 1926), recently resurrected as species of the complex Lutzomyia intermedia (Lutz & Neiva, 1912) by Marcondes (1996), in an ACL endemic rural area in Southeastern of Brazil, by the mark-release-recapture technique. The anthropophilic behavior of the species, its predominance in modified environments and its presence in houses were people have become infected indicates L. neivai as the suspected vector in a large area (Gomes 1994, Tolezano 1994, Casanova et al. 1995, Marcondes et al. 1998, Teodoro et al. 2001, Salomon et al. 2003, 2004, Andrade Filho et al. 2003. MATERIALS AND METHODSStudy area -The study was carried out in an ACL endemic rural area in municipality of Conchal (22°18'S and 47°13'W), Mogi Guaçu River Valley, São Paulo (Fig. 1). This locality has a secondary remnant gallery forest, which covers the left margin of Mogi Guaçu river (Fig. 1), small farms with fruit-trees, vegetables, and domestics animals such as chickens and pigs. According to the Köeppen classification, the climate is subtropical warm with dry winter (Cwa). The average annual rainfall is 1381 mm and the average annual temperature is 21.6°C. Previous studies demonstrated that L. neivai is the predominant species in this area (...

The aim of this work is to present aspects related to the ecology of Rhodnius nasutus

The present study was effected aiming the verification of the seasonal, spatial and hourly of the phlebotominic species found in the county of Itupeva. Captures were performed fortnightly and 864 sand flies were collected between april/94 and march/95. 81.3% of the captured specimens belonged to 4 species: L. migonei (32.4%), L. whitmani (26.0%), L. intermedia (12.0%) e L. fischeri (10.9%). Such species showed larger densities during the cold and dry season of the year (from april to september/94) and were more active between the second and the fifth hour after twilight. L. migonei predominated almost in all the investigated surroundings being followed by L. whitmani and L. longipalpis in the domestic environments. In conclusion it is thought that in conjunction with L. intermedia, a suspect vector in the State of São Paulo, L. migonei and L. whitmani may have an important role in the transmission of cutaneous leishmaniasis in the area under study.

BackgroundThe scarcity of information on the immature stages of sand flies and their preferred breeding sites has resulted in the focus of vectorial control on the adult stage using residual insecticide house-spraying. This strategy, along with the treatment of human cases and the euthanasia of infected dogs, has proven inefficient and visceral leishmaniasis continues to expand in Brazil. Identifying the breeding sites of sand flies is essential to the understanding of the vector's population dynamic and could be used to develop novel control strategies.Methodology/Principal findingIn the present study, an intensive search for the breeding sites of Lutzomyia longipalpis was conducted in urban and peri-urban areas of two municipalities, Promissão and Dracena, which are endemic for visceral leishmaniasis in São Paulo State, Brazil. During an exploratory period, a total of 962 soil emergence traps were used to investigate possible peridomiciliary breeding site microhabitats such as: leaf litter under tree, chicken sheds, other animal sheds and uncovered debris. A total of 160 sand flies were collected and 148 (92.5%) were L. longipalpis. In Promissão the proportion of chicken sheds positive was significantly higher than in leaf litter under trees. Chicken shed microhabitats presented the highest density of L. longipalpis in both municipalities: 17.29 and 5.71 individuals per square meter sampled in Promissão and Dracena respectively. A contagious spatial distribution pattern of L. longipalpis was identified in the emergence traps located in the chicken sheds.ConclusionThe results indicate that chicken sheds are the preferential breeding site for L. longipalpis in the present study areas. Thus, control measures targeting the immature stages in chicken sheds could have a great effect on reducing the number of adult flies and consequently the transmission rate of Leishmania (Leishmania) infantum chagasi.

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The survival, absolute population size, gonotrophic cycle duration, and temporal and spatial abundance of Nyssomyia neivai (Pinto) were studied in a rural area endemic for American cutaneous leishmaniasis (ACL) in Conchal, São Paulo State, southeastern Brazil, using mark-release-recapture techniques and by monitoring population fluctuation. The monthly abundance exhibited a unimodal pattern, with forest and domicile habitats having the highest relative abundances. A total of 1,873 males and 3,557 females were marked and released during the six experiments, of which 4.1-13.0% of males and 4.1-11.8% of females were recaptured. Daily survivorship estimated from the decline in recaptures per day was 0.681 for males and 0.667 for females. Gonotrophic cycle duration was estimated to be 4.0 d. Absolute population size was calculated using the Lincoln Index and ranged from 861 to 4,612 males and from 2,187 to 19,739 females. The low proportion of females that reach the age when they are potentially infective suggests that N. neivai has a low biological capacity to serve as a vector and that factors such as high biting rates and opportunistic feeding behavior would be needed to enable Leishmania (Viannia) braziliensis Vianna transmission. This agreed with the epidemiological pattern of ACL in southeastern Brazil that is characterized by low incidence, with isolated cases acquired principally within domiciliary habitats.