RESUMO
Sera were examined from an age-stratified sample of two Caribbean communities using the Toxocara-ELISA with larval ES antigen. Seropositivity was markedly age dependent, attaining maximal values (40 and 60%) in 5-15 year olds and declining in adults. The rate of acquisition of infection with Toxocara canis and the age-prevalence profile are similar to those of Ascaris lumbricoides and Trichuris trichiura. It is suggested that toxocariasis is likely to be prevalent in tropical areas with endemic geohelminthiasis.
Assuntos
Ascaríase/epidemiologia , Toxocaríase/epidemiologia , Adolescente , Adulto , Fatores Etários , Animais , Anticorpos Anti-Helmínticos/análise , Criança , Pré-Escolar , Humanos , Lactente , Toxocara/imunologia , Toxocaríase/imunologia , Tricuríase/epidemiologia , Índias Ocidentais , ZoonosesRESUMO
A study of gastrointestinal parasitic infection was conducted in four communities in the Parish of Westmoreland, Jamica. All blood smears (n=1,025) werw negative and 63,7% of stool specimens (n=696) contained ova/cysts of one or more of 7 helminth and 9 protozoan spcecies. Trichuris and Giardia were the most prevalent species. Prevalence was markedly age-dependent, with infection occuring most commonly in children. It is concluded that gastreointestinal parasitic infections persist at intensity and prevalence levels likely to have a significant impact on community health
Assuntos
Humanos , Infecções por Protozoários/epidemiologia , Gastroenteropatias/patologia , Helmintíase/epidemiologia , Estudos Transversais , Fatores Etários , Enteropatias Parasitárias/epidemiologiaRESUMO
The study examines the distribution of Trichuris trichiura infection in a village community in St Lucia, West Indies. The infection intensity of the same age-stratified population was assessed (by drug expelled worm burden and faecal egg count) at the initiation of the study, and after 17 months of reinfection following treatment. The frequency distribution of worm numbers per person was similar at both periods of sampling. There was a significant correlation between the initial infection intensity of an individual, and the intensity acquired by the same individual following the 17 month period of reinfection. This relationship was observed in a broad range of host age classes. The study provides firm evidence that individuals are predisposed to heavy (or light) T. trichiura infection.
Assuntos
Fezes/parasitologia , Tricuríase/parasitologia , Trichuris/isolamento & purificação , Adolescente , Adulto , Criança , Pré-Escolar , Humanos , Lactente , Mebendazol/uso terapêutico , Contagem de Ovos de Parasitas , Recidiva , Tricuríase/tratamento farmacológico , Tricuríase/epidemiologia , Índias OcidentaisRESUMO
The gastrointestinal helminth infection status of an age-stratified sample from a single Caribbean community was assessed using anthelmintic expulsion techniques. The same sample was re-assessed in a similar manner after a 17 month period of re-infection. The age-prevalence profile of Ascaris lumbricoides was convex while that of Trichuris trichiura was asymptotic. The age-intensity profiles of both species were convex. These differing patterns are attributed to differences in the absolute worm burdens of the 2 species. The frequency distributions of infection intensity were similar for both species, and largely independent of host age. The basic reproductive rate of A. lumbricoides (Ro = 1-1.8) was similar to that recorded elsewhere and much lower than that of T. trichiura (Ro = 4-6), implying that the latter is intrinsically more resistant to control. Individual hosts were predisposed to high (or low) intensity infection with either species, although predisposition to both species simultaneously was not conclusively demonstrated. Further studies are required to determine the cause of these observations.
Assuntos
Ascaríase/epidemiologia , Tricuríase/epidemiologia , Adolescente , Adulto , Fatores Etários , Animais , Ascaríase/parasitologia , Ascaris/isolamento & purificação , Criança , Pré-Escolar , Fezes/parasitologia , Humanos , Lactente , Pessoa de Meia-Idade , Dinâmica Populacional , Tricuríase/parasitologia , Trichuris/isolamento & purificação , Índias OcidentaisRESUMO
Age-related changes in the average worm burden and the prevalence of Trichuris trichiura infection, in a village community in St. Lucia, were examined by field studies based on worm expulsion techniques. Horizontal age-intensity profiles were convex in form with peak parasite loads occurring in the 2 to 15-year-old children. Prevalence is shown to be a poor indicator of changes in average worm load with age. Faecal egg counts (epg and epd) provide a qualitative measure of worm burdens since fecundity is shown to be approximately independent of worm load. The parasites were highly aggregated within the study community, with most people harbouring low burdens while a few individuals harboured very heavy burdens. Of the total parasite populations in the study sample, 84% were harboured by the 2 to 15-year-old children. Of those individuals harbouring 100 worms or more, 87% were in the 2 to 10-year-old age range. Crude estimates of population parameters (basic reproductive rate, 4-5; rate of reinfection, 90 year-1) suggest that the rate of reinfection is higher than for other helminth parasites of man. The control of morbidity and parasite transmission is discussed in the context of targeting drug treatment at the child segment of the study population.
Assuntos
Tricuríase/epidemiologia , Adolescente , Adulto , Fatores Etários , Idoso , Animais , Criança , Pré-Escolar , Fezes/parasitologia , Fertilidade , Humanos , Pessoa de Meia-Idade , Contagem de Ovos de Parasitas , Fatores Sexuais , Trichuris/fisiologia , Índias OcidentaisRESUMO
The study reports the results of a summary of the prevalence and symptomatology of paediatric toxocariasis in Anse-la-Raye, St. Lucia. The seroprevalence of Toxocara canis among the children, as determined by ELISA, was 86%, the highest level recorded to date. In contrast, the prevalence of infection in dogs was not abnormally high, although the canine population was large and unconstrained compared to that in industrial countries. The presence of infective ova in peridomestic areas and the widespread practice of pica among children in the village probably combine to enhance exposure to infection.
Assuntos
Ascaríase/epidemiologia , Toxocaríase/epidemiologia , Animais , Criança , Pré-Escolar , Cães , Humanos , Lactente , Microbiologia do Solo , Toxocara/isolamento & purificação , Toxocaríase/parasitologia , Índias OcidentaisRESUMO
Population dynamical parameters of Trichuris trichiura infections in children were estimated from longitudinal intensity and prevalence data from a population (n = 23) in a children's home in Jamaica. The theoretical predictions of a deterministic model incorporating these parameters were approximated to observed horizontal-age prevalence data from a naturally infected population (n = 203) of children in a St. Lucian village, and a rough estimate of the basic reproductive rate (Ro = 8-10) of T. trichiura obtained. The findings suggest that T. trichiura populations are intrinsically more difficult to control by traditional mass-treatment chemotherapy (eradication requires greater than 91% of the population to be treated every 6 months for greater than 5 years) than are populations of Ascaris, but may be more susceptible to selective chemotherapy programmes which aim to treat only the most heavily infected individuals.
Assuntos
Tricuríase/tratamento farmacológico , Fatores Etários , Criança , Pré-Escolar , Fezes/parasitologia , Feminino , Humanos , Lactente , Jamaica , Masculino , Mebendazol/uso terapêutico , Modelos Biológicos , Contagem de Ovos de Parasitas , Dinâmica Populacional , Recidiva , Tricuríase/epidemiologia , Tricuríase/parasitologia , Trichuris/crescimento & desenvolvimento , Índias OcidentaisRESUMO
The Trichuris trichiura worm burdens of 23 children living in a Place-of-Safety in Kingston, Jamaica, were assessed by stool collection for more than five days after treatment with mebendazole. This procedure was repeated after a seven-month period of natural re-infection. For both collections the maximum rate of worm expulsion was achieved on the fourth day after starting treatment. The worm population distributions were overdispersed and well described by the negative binomial probability model (k = 0.29) in each case. For any one individual, the number of worms passed on the first expulsion was unrelated, absolutely or relatively, to the number passed on the second. These data suggest that: knowledge of the time dependency of helminth expulsion is essential for the accurate estimation of worm burdens by this method; populations of Trichuris are more highly aggregated than those of Ascaris and may thus be more susceptible to control by selective rather than random chemotherapy; and the inherent predisposition of hosts to infection may be of minor importance in determining the distribution of worms in the population-heavily infected hosts appear no more or less likely to acquire large worm burdens on subsequent exposures.