THE EFECTS OF SETTLEMENT ON THE PREVALENCE OF AscarisINFECTION IN TWO AMERINDIAN POPULATIONS OF THE BRAZILIAN AMAZON

Abstract

-Studies were made of the intestinal parasites of Amerindian populations of the Uaupes River basin of Brazil. Three groups were sampled: 1) Tukano fisher-agriculturalists who live in permanent riverine villages; 2) Maku hunter-horticulturalists who live in close contact with the Tukano fishing villages; and 3) Maku who inhabit the forest interior and have little contact with permanent settlements. Fecal samples were collected from 498 individuals of which 220 were from the first group, 135 from de second and 143 from the third. The samples were analyzed by means of microflotation and centrifugal sedimentation. A total of 18 protozoan and helminth species were recorded based on the presence of cysts or eggs. These included five nematode species that could not be identified. The three common pathogenic nematodes were found to be prevalent: the hookworm, Necator americanus (96%); the whipworm, Trichuris trichiura (77%) and the large roundworm, Ascaris lumbricoides (75%). The prevalence of Ascaris among the villages was found to vary from 56 to 100%. Individuals living in, or associated with, permanent settlements had higher prevalence and intensity rates than those living in the nomadic hunter-gatherer way. This is shown to be directly related to fecal contamination of the environment in and around permanent settlements. The prevalence of Ascaris in a population can be used as an indicator of such environmental contamination.Key words: Ascaris, roundworms, parasites, helminths, indians.O efeito de permanência sobre a prevalência de infecção por Ascaris em duas populações de ameríndios da amazônia brasileira.RESUMO -Estudos foram feitos dos parasitas intestinais de populações de ameríndios da bacia do Rio Uaupes no Brasil. Três grupos foram amostrados: 1) Tukano pescadores-agricultores que vivem em aldeias ribeirinhas permanentes; 2) Maku caçadores-horticultores que vivem em contato próximo com as aldeias pescadoras dos Tukano; e 3) Maku que habitam o interior da selva e têm pouco contato com aldeias permanentes. Amostras fecais foram obtidas de 498 indivíduos dos quais 220 foram do primeiro grupo, 135 do segundo e 143 do terceiro. As amostras foram analisadas pelos métodos de microflutuação e por sedimentação centrífuga. Um total de 18 espécies de protozoários e helmintos foram assinaladas com base na presença de cistos ou ovos. Entre estas, cinco espécies de nematóides não puderam ser identificadas. As três espécies de nematóides patogênicas comuns foram prevalentes: Necator americanus (96%); Trichuris trichiura (77%) e Ascaris lumbricoides (75%). A prevalência de Ascaris entre as aldeias variou entre 56 e 100%. Indivíduos morando em, ou associados com, aldeias permanentes apresentaram taxas de prevalência e intensidade mais elevadas do que as pessoas que continuavam vivendo como caçadores nômades. Isto tem uma relação direta com a contaminação fecal do ambiente dentro e ao redor das aldeias permanentes. A prevalência de Ascaris numa população pode ser utilizada como uma indicadora deste tipo de contamina...

Tuberculin Skin-Test Reactions Are Unaffected by the Severity of Hyperendemic Intestinal Helminth Infections and Co-Infections

“…is probably explained by enhanced hygiene or frequent antihelminthic administration in health-care staff. Because almost all participants had intestinal helminth infections, similar to other studies in this region, 18,19 the current research could not meaningfully compare naturally infected versus uninfected individuals. However, our previous research in a nearby community 12 and research in other settings 19 have shown that TST results do not differ between individuals who are naturally infected versus naturally uninfected with intestinal helminths.…”

“…18,19 Despite this, gastrointestinal symptoms were rare and were not associated with high helminth burden or helminth co-infections. 20 The stool microscopy was performed by staff blinded to information about participants, and it was striking that only health-care professionals were free from intestinal helminths.…”

A systematic review of zoonotic enteric parasitic diseases among nomadic and pastoral people

“…Several zoonotic enteric parasites can be transmitted to humans from dogs, cats, and other pets/companion animals [ 101 ]. In this review, many of the study authors pointed out that interactions with dogs, in particular, are a high risk for ZEP transmission among nomadic and pastoralist communities largely due to the practice of throwing viscera and offal from slaughtered animals to the dogs to eat [ 51 , 54 – 57 , 59 , 61 , 62 , 64 – 66 , 68 – 71 , 73 , 89 , 91 , 98 – 99 , 102 ]. For example, this behavior is estimated to increase the exposure risk for acquiring Echinococcosus spp .…”

“…Wildlife share the same space as the pastoral communities in many regions and due to their bounty and diversity, ZEPs are provided multiples opportunities for intermediate and definitive host species for which to proliferate [ 21 ]. Some nomadic communities also hunt wildlife leading to more exposure threats for ZEP transmission to humans [ 47 , 51 , 61 , 62 , 65 , 67 , 81 , 64 – 65 ].…”

The Chief Is Dead, Long Live... Who? Descent and Succession in the Protohistoric Chiefdoms of the Greater Antilles

“…There are many ethnographic examples where transmission of leadership or elites' rules of descent are different than the ones for the population at large. Chernela (1993), in discussing the kinship and marriage system among the Wanano, explained that most of these rules were followed primarily, if not exclusively, by the higher ranking lineages and not by the lower-status ones. For this reason descent was not taken as seriously by the lower-status groups as it was among the high-ranked ones.…”