Jeronimo Alencar

Prevalência de Anofelinos (Diptera: Culicidae) no Crepúsculo Vespertino em Áreas da Usina Hidrelétrica de Itaipu, no Município de Guaíra, Estado do Paraná, Brasil

Systematic collections of anophelines were conducted from November 1994 to August 1995 from 18:00 to 20:00 hr using Shannon traps and human-bait along the lake margin which forms the Itaipu Hydroelectric reservoir, State of Parana, Brazil. Species prevalence was studied at 15 min intervals. Anopheles albitarsis sensu latu and An. galvaoi, were the most frequently collected mosquitoes. All Anopheles species populations peaked between 18:45 and 19:30 hr. The observations illustrate the existence of a haematophagic activity cycle during the early evening hours: exogenous stimulus (the beginning of sunset) ® Shannon trap (light attraction) ® human bait (haematophagy) ® rest and digestion ® exogenous stimulus ® Shannon trap or surrounding vegetation. The greater abundance of An. albitarsis collected in human-bait and Shannon trap suggests it may be a potential malaria vector in the region

Larvicidal Activity of Grandisin Against Aedes aegypti

Abstract Dengue is a tropical disease caused by an arbovirus transmitted by the mosquito Aedes aegypti. Because no effective vaccine is available for the disease, the strategy for its prevention has focused on vector control by the use of natural insecticides. The aim of this study was to evaluate the larvicidal activity of the lignan grandisin, a leaf extract from Piper solmsianum, against Ae. aegypti.

Ecologia de mosquitos (Diptera, Culicidae) em áreas do Parque Nacional do Iguaçu, Brasil: 1 Distribuição por hábitat

A study of the mosquito fauna in the Iguacu National Park focused on population behavior in four biotopes with different types of plant cover inside the Park. Systematic bimonthly diurnal and nocturnal human bait and Shannon trap captures were conducted in both forest and domiciliary environments over the course of 24 months. A total of 20,273 adult mosquito specimens belonging to 44 species were collected: Ochlerotatus serratus (10.3%), Haemagogus leucocelaenus (9.7%), Mansonia titillans (9.6%), and Chagasia fajardoi (8.8%) were the most frequently captured mosquitoes. Anopheles cruzii, Runchomyia theobaldi, Wyeomyia aporonoma, and Wy. confusa were captured almost exclusively in well-preserved areas with dense forest cover. Culex nigripalpus, Oc. pennai, Oc. serratus, Sabethes purpureus, and Sa. albiprivus were captured in three essentially sylvatic biotopes. Species captured in the forest areas around a dam were: An. albitarsis s.l., An. galvaoi, An. evansae, An. fluminensis, Coquillettidia venezuelensis, Cq. juxtamansonia, Wy. quasilongirostris, and Onirion personatum, Ch. fajardoi, Cq. fasciolata, Cq nitens, and Ma. titillans were the most frequently captured species in a residential area.

Diversidade de criadouros e tipos de imóveis freqüentados por Aedes albopictus e Aedes aegypti

OBJECTIVE To assess the diversity of oviposition containers and buildings where females of Aedes albopictus and Aedes aegypti can be found. METHODS A study was carried out in the city of Rio de Janeiro, Southern Brazil, between 2002 and 2003. Larvae in different types of buildings were investigated, and immature forms found were then sent to the laboratory for identification. The larval frequency for both mosquitoes was estimated in the oviposition containers available. The Breteau index and the building infestation index were calculated and differences were tested using the Chi-square test. RESULTS The types of buildings that were positive for Aedes albopictus and Aedes aegypti were: dwellings (83.9%); churches, schools, clubs (6.8%); vacant land (6.4%); and businesses (2.8%). Of 9,153 larvae collected, 12.0% were Aedes albopictus and 88.0% were Aedes aegypti. Aedes albopictus were mostly found in drains (25.4%); cans, bottles, empty bottles (23.9%); and plant vases (16.2%). Aedes aegypti was much more frequently found than Aedes albopictus (chi(2)=145.067; p<0.001). Both species were significantly more frequent in artificial than in natural oviposition containers (chi(2)=31.46; p<0.001). The building infestation index and Breteau index for Aedes albopictus were 0.3% and 0.28% in 2002 and 0.4% and 0.5 in 2003, respectively. For Aedes aegypti, they were 1.0%, 1.16 in 2002 and 3.5% and 4.35 in 2003, respectively. CONCLUSIONS The present study assessed the frequencies of Aedes albopictus and Aedes aegypti females in various types of oviposition containers and types of buildings. The abundant availability of artificial containers in dwellings, associated with the capacity of Ae. albopictus to be also found in natural oviposition containers, has greatly contributed for their gradual adaptation to human environment.

Ecology of Anopheline (Diptera, Culicidae), malaria vectors around the Serra da Mesa Reservoir, State of Goiás, Brazil: 1 - Frequency and climatic factors

The ecology of anopheline species (Diptera, Culicidae) was studied in the vicinity of the Serra da Mesa Reservoir, State of Goiás, Brazil. Climatic factors and frequency of anopheline populations were analyzed. Bimonthly human-bait and Shannon trap captures were conducted for 36 consecutive months (January 1997 through December 1999). A total of 5,205 adult anophelines belonging to five species were collected. Anopheles darlingi was the most frequently collected anopheline (61.4%), followed by An. albitarsis s.l. (35.4%), An. triannulatus. (2.5%), An. oswaldoi (0.4%), and An. evansae (0.2%). The water level and vegetation along the banks of the reservoir were crucial to the frequency of the various anopheline species. Climatic factors had a secondary influence. The reservoirs water-level stability, increased frequency of An. darlingi, and the arrival of gold prospectors were responsible for the increase in malaria cases.

Feeding Patterns of Haemagogus janthinomys (Diptera: Culicidae) in Different Regions of Brazil

Abstract New data on the feeding patterns of Haemagogus (Haemagogus) janthinomys Dyar from different geographical regions of Brazil, by using the precipitin test as the bloodmeal-identifying tool, are presented. The following antisera were used: bird, dog, human, rodent, cattle, horse, and opossum. The origins of 287 bloodmeals were identified, whereas 33 specimens were negative to the antiserums tested. Among the reactive specimens, 174 (60.6%) fed on only one food source, of which 35.1% originated from birds, 19.5% from rodents, 12.6% from humans, 10.3% from cattle, 10.3% from opossums, 7.5% from dogs, and 4.6% from horses. One hundred six (37.0%) mosquitoes fed on two sources, of which the most common combinations were bird + rodent (16.0%), bird + human (10.4%), and horse + human (9.4%). Seven (2.4%) mosquitoes fed on three different hosts. Our results suggest that Hg. janthinomys is more eclectic and opportunist than previously known in relation to its hosts and that such patterns are probably highly adaptive to a temporally and spatially variable environment.

Serological detection of West Nile virus in horses and chicken from Pantanal, Brazil

In an effort to detect West Nile virus (WNV) in Brazil, we sampled serum from horses and chickens from the Pantanal region of the state of Mato Grosso and tested for flavivirus-reactive antibodies by blocking ELISA. The positive samples were further confirmed for serological evidence of WNV infection in three (8%) of the 38 horses and one (3.2%) of the 31 chickens using an 80% plaque-reduction neutralisation test (PRNT80). These results provide evidence of the circulation of WNV in chickens and horses in Pantanal.

Feeding Patterns of Haemagogus capricornii and Haemagogus leucocelaenus (Diptera: Culicidae) in Two Brazilian States (Rio de Janeiro and Goias)

Abstract We present the identification of bloodfeeding sources of Haemagogus (Haemagogus) capricornii Lutz and Haemagogus (Conopostegus) leucocelaenus (Dyar & Shannon) (Diptera: Culicidae) from different regions of Brazil, as analyzed by precipitin tests. Anti-sera for bird, bovine, equine, human, opossum, and rodent were used. Two hundred one mosquitoes were examined (147 Hg. leucocelaenus and 54 Hg. capricornii), of which 177 reacted for some anti-serum. For Hg. leucocelaenus, 86 (68.3%) reacted to one blood source, 38 (30.2%) to two sources, and two (1.6%) to three sources; the combinations of bird + human (18.4%), bird + rodent (15.8%), and bird + marsupial (15.8%) were the most frequent. For Hg. capricornii, 34 (66.7%) reacted to one blood source; combinations bird + rodent (37.5%) and bird + marsupial (25%) were the most frequent combinations. Mosquito preference for bloodfeeding sources was different in these areas, possibly because of the availability of sources. This diversity of sources can have important epidemiological implications.

DESCRIPTION OF THREE PRACTICAL AND INEXPENSIVE DEVICES FOR THE COLLECTION OF MOSQUITOES AND OTHER SMALL INSECTS

ABSTRACT Three new devices for collecting and maintaining mosquitoes and other small insects are described. A suction tube, composed of two pieces of plastic transparent tube, the narrower fitted in the wider, with the mouth protected by the use of voile, is cheap and practical and can be transported around the neck. A 900-ml plastic transparent box is utilized for the restraint of sucked insects and, with the adaptation of two pieces of plastic tube, as a suction chamber.

Observações Sobre Padrões Alimentares de Mosquitos (Diptera: Culicidae) no Pantanal Mato-Grossense

O habito alimentar dos culicideos foi estudado atraves da tecnica de precipitina. As coletas foram realizadas no km 52 da rodovia Transpantaneira (MT-060), a 65km da sede do municipio de Pocone (MT). Bimestralmente, de dezembro de 2002 a dezembro de 2003, foram realizadas capturas em armadilha Shannon e CDC automatica a base de CO2 das 15:00h as 21:00h. Foram utilizados os seguintes anti-soros: ave, roedor, humano, cavalo, boi, capivara e sapo. Das 2.134 femeas capturadas, 1.946 (92,2%) foram coletadas em armadilha de Shannon e 188 (8,8%) em armadilha CDC. Desse total, 276 femeas (13,0%) estavam ingurgitadas e proprias para o teste de precipitina, sendo 235 (85,1%) coletadas em armadilha de Shannon e 41 (14,9%) em CDC. Verificou-se que 84,2% dos especimes analisados reagiram para uma fonte alimentar e 15,8% para duas fontes. As especies Mansonia titillans (Walker), Culex nigripalpus (Theobald), Aedeomyia squamipennis (Theobald) e Psorophora albigenu (Peryassu) foram as mais frequentes e reagiram para todos os anti-soros. Os anofelinos Anopheles albitarsis (Lynch-Arribalzaga), An. matogrossensis (Lutz & Neiva) e An. triannulatus (Neiva & Pinto), com poucos especimes, reagiram para cinco anti-soros. As demais especies apresentaram positividade que variou de tres a seis anti-soros. As estimativas do indice alimentar (feeding index) revelaram resultados positivos para oito especies de culicideos, destas cinco apresentaram preferencia marcante para o hospedeiro capivara.