RESUMO
Adult female populations of Haemagogus leucocelaenus (Dyar and Shannon), the sylvan vector of yellow fever, were monitored weekly during 1981-82 by human collectors on the ground at Point Gourde in Chaguaramas Forest, 16 km west of Port of Spain, Trinidad. Hg.leucocelaenus showed only diurnal landing activity, from 06.00 to 18.00 hours (sunrise to sunset, universal time), with a single peak of activity between 10.00 and 14.00 hours. Densities of Hg.leucocelaenus during the wet season (May-November) were about double the level recorded during the dry season (December-April). Monthly parous rates averaged 53.9% (range 25-90%) and some females were up to five-pars. Retained eggs (range 2-6, mean 4/female) were found in the ovaries of 0.34% of landing females, all of which had stage 1 ovarian follicles for the next gonotrophic cycle. Therefore blood-feeding is not inhibited by egg retention. Hg.leucocelaenus vector potential is reappraised in the light of these findings.
Assuntos
Culicidae , Mordeduras e Picadas de Insetos , Fatores Etários , Animais , Feminino , Humanos , Ovário , Densidade Demográfica , Reprodução , Estações do Ano , Trinidad e Tobago , Índias OcidentaisRESUMO
The mosquito Haemagogus equinus is a known vector of yellow fever (YF) in central America. Seasonal abundance, daily biting activity and the age composition of adult Hg.equinus female populations were monitored weekly during 1981-82 by human collectors on the ground at Point Gourde Forest, Chaguaramas, 16 km west of Port of Spain, Trinidad. 2. Landing collections of Hg.equinus showed diurnal activity from 06.00 to 20.00 hours (suntime), with a single peak between 08.00 and 14.00 hours. 3. Overall, 5.6% of Hg.equinus were collected during the dry season (December-April) and 94.4% during the wet season (May-November). 4. Mean density of Hg.equinus in relation to man ranged from 0.35/man-day in February to 133/man-day in July, with averages of 2.8 in the wet season, 36.9 in the dry season and 22/man-day for the whole year. 5. Monthly parous rates averaged 62.1% (range 0-88%); 2.8% of females were 2-pars, another 2.8% were 3-pars, but no older females of Hg.equinus were found (sample size 467). 6. These age-grading data indicate that Hg.equinus females have relatively short life expectancy and hence low vector potential, which may help to explain why YF virus has seldom been isolated from this vector species.
Assuntos
Culicidae/fisiologia , Animais , Comportamento Alimentar , Feminino , Interações Hospedeiro-Parasita , Humanos , Insetos Vetores , Reprodução , Estações do Ano , Trinidad e TobagoRESUMO
When 239 (1982) and 361 (1991) five- and nine-year-old children in St. Kitts were assessed for the presence of parasitic infections, there were significant reductions in the prevalence of trichuriasis from 83% to 58%, of ascariasis from 24% to 8.6% and of giardiasis from 15% to 9.4%. Anthelminthic use, which appeared to be the most important responsible intervention tool, remained roughly at the same level at 59-51%. However, the types of anthelminthics used changed over the period. Piperazine citrate, which was used by 66% in 1982, only had 35% usage in 1991. Albendazole which was not used at all in 1982 was taken by 32% of the children in 1991 and at the same time use of laevo-tetramisole increased by 20% from 14%. Suggestions are made for an island-wide mass intervention programme to manage parasitic infections.
Assuntos
Enteropatias Parasitárias/epidemiologia , Anti-Helmínticos/uso terapêutico , Criança , Pré-Escolar , Fezes/parasitologia , Helmintíase/tratamento farmacológico , Helmintíase/epidemiologia , Humanos , Enteropatias Parasitárias/tratamento farmacológico , Prevalência , Infecções por Protozoários/tratamento farmacológico , Infecções por Protozoários/epidemiologia , Fatores de Tempo , Índias Ocidentais/epidemiologiaRESUMO
Larval populations of the mosquito Aedes aegypti were suppressed by predatory Toxorhynchites moctezuma mosquito larvae released systematically in a village on Union Island (Saint Vincent and the Grenadines) during March-December 1988. Eggs and larvae of Tx.moctezuma were transported from Trinidad and introduced into all semi-permanent and permanent water-holding containers in the experimental village at Clifton. The semi-isolated village of Ashton served as control. Base-line Ae.aegypti indices (house, ovitrap, Breteau, cistern/tank, drum/barrel, small containers) were obtained for the two villages over a 4-month period prior to the introduction of the predatory Tx.moctezuma mosquito larvae. After sustained releases of predators for 5 months, all indices of Ae.aegypti were lower in the treated village than in the untreated village during the last 3 months of the year.
Assuntos
Aedes/fisiologia , Culicidae/fisiologia , Insetos Vetores/fisiologia , Controle Biológico de Vetores , Animais , Custos e Análise de Custo , Larva/fisiologia , Controle Biológico de Vetores/economia , Comportamento Predatório , Estações do Ano , Água , Índias OcidentaisRESUMO
Seasonal and spatial distributions of the arbovirus vector mosquito Culex (Melanoconion) caudelli Dyar and Knab (Diptera: Culicidae) in the Aripo-Wallerfield forest, Trinidad, were studied by collecting mosquitoes attracted to mouse-baited traps in forest, ecotone and savannah, one day per week throughout the year, 98% of the Cx caudelli mosquitoes were collected during the wet season, with a significant positive correlation between rainfall and mosquito catch. The reverse occurred during the dry season. Cx caudelli displayed a preference for the ecotone where 67% were collected, while 32% and 1% were collected in the forest and savannah respectively.
Assuntos
Infecções por Arbovirus/transmissão , Culex/crescimento & desenvolvimento , Insetos Vetores/crescimento & desenvolvimento , Animais , Umidade , Chuva , Estações do Ano , Temperatura , Trinidad e TobagoRESUMO
1. Age composition, seasonal abundance and diel patterns of landing activity of the sylvan vector of yellow fever Haemagogus janthinomys Dyar were monitored weekly during 1981-82 by human collectors on the ground at Point Gourde in Chaguaramas Forest, 16 km west of Port of Spain, Trinidad. 2. Landing collections of Hg. janthinomys showed only diurnal activity, from 06.00 to 18.00 (sunrise to sunset, universal time), with a single peak of activity between 10.00 and 16.00 hours. 3. Densities of Hg. janthinomys were about 6 times greater during the wet season (May-November) than during the dry season (December-April); the annual Williams' mean landing rate on two collectors was 9.3 per day. 4. Monthly parous rates averaged 59% (range 0-86%) and some females were up to seven-pars. Retained eggs (range 1-21, mean 7.7/female) were found in the ovaries of 1.3% of landing females, all of which had stage I ovarian follicles for the next gonotrophic cycle. Hence blood-feeding is not inhibited by egg retention, which might promote transovarial transmission of virus. Implications of these findings are discussed in relation to yellow fever epidemiology.
Assuntos
Culicidae/fisiologia , Mordeduras e Picadas de Insetos/parasitologia , Insetos Vetores/fisiologia , Febre Amarela/transmissão , Animais , Ritmo Circadiano , Culicidae/crescimento & desenvolvimento , Feminino , Humanos , Insetos Vetores/crescimento & desenvolvimento , Paridade , Chuva , Estações do Ano , Fatores de Tempo , Trinidad e TobagoRESUMO
A colony of Toxorhynchites moctezuma was established at the Caribbean Epidemiology Centre in Trinidad in 1984. Toxorhynchites moctezuma was maintained in cages with high humidities. Eggs were deposited most frequently in a cut bicycle tire containing water. A minimum of 42 h was required for hatching, but 94% hatched between 43 and 51 h. Aedes aegypti larvae were supplied as prey. Larval development times varied with the quantity of prey offered, but when fed ad lib, peak developmental time was 18 days. Mean pupal developmental time was 5.5 days. Although only 12% of larvae survived to pupation in 3 years of production, our experience indicates this species would be a likely candidate for mass production and release.
Assuntos
Culicidae/fisiologia , Oviposição , Animais , Culicidae/crescimento & desenvolvimento , Feminino , Umidade , Larva/crescimento & desenvolvimento , Masculino , Pupa/crescimento & desenvolvimento , TemperaturaRESUMO
The occurrence of the first seven cases of visceral larva migrans in Trinidad and Tobago is described. All cases occurred in children of the same family. The ELISA test was used to confirm the clinical diagnosis.
PIP: Visceral larva migrans is a syndrome caused by the extraintestinal migration of larval nematodes of wild and domestic animals through human tissues. Most cases occur in children under 5 years of age, with the common dog round worm apparently being the primary causative agent. This paper describes the occurrence of the first 7 cases of visceral larva migrans in Trinidad and Tobago. Cases occurred among siblings in the same family and were confirmed using the ELISA test. A mentally retarded 10-year old East Indian male was admitted to the Port of Spain General Hospital with a strong history of pica, recurrent wheezing, and epilepsy. Five siblings and one cousin were found living under extremely unsanitary conditions and in dire poverty. All had pica and Toxocara canis eggs were found in the dirt surrounding the dwelling. These eggs are most probably the common source of infection. Infection with Toxocara species is probably far more common than reported in Trinidad, given the large stray dog population and areas of primitive sanitary conditions. ELISA tests could be used to reveal additional infections in the country.
Assuntos
Características da Família , Larva Migrans Visceral/epidemiologia , Tipagem e Reações Cruzadas Sanguíneas , Criança , Pré-Escolar , Ensaio de Imunoadsorção Enzimática/normas , Eosinofilia/etiologia , Feminino , Hepatomegalia , Humanos , Larva Migrans Visceral/sangue , Larva Migrans Visceral/complicações , Masculino , Pica/complicações , Sensibilidade e Especificidade , Conglomerados Espaço-Temporais , Trinidad e Tobago/epidemiologiaRESUMO
The seasonal incidence and diel oviposition patterns of sylvan Haemagogus celeste and Hg. leucocelaenus in the Pt. Gourde Forest, Trinidad, were monitored weekly for 53 consecutive weeks using conventional ovitraps. During the dry season peak oviposition by Hg. celeste occurred between 10.00 and 12.00 hours, and that by Hg. leucocelaenus between 12.00 and 14.00 hours; during the wet season peak oviposition by both species occurred between 12.00 and 14.00 hours. Diurnal patterns of oviposition were observed for both species during the wet and dry seasons. The numbers of ovipositions and of eggs laid during the wet season were, for both species, significantly higher (P greater than 0.001) than those observed during the dry season.