Larva migrans in Votuporanga, São Paulo, Brazil: Where does the danger hide? / Larva migrans em Votuporanga, SP, Brazil: Onde se esconde o perigo?

Abstract Soil samples collected near municipal schools (public/EMEI and private/EPEI schools), clubs (CLB), public squares (PS) and residential condominiums (CND) and samples of animal faeces from the Zoonosis Control Centre (CCZ) of the municipality of Votuporanga/SP were analysed using the Baermann method for the detection of zoonotic helminth larvae. The prevalence rates of the nematode genera identified were determined, and the results were compared using Fisher's exact and chi-square frequency tests. Information about cases of larvae migrans in the population were collected from the Family Health Units and the private health plans. All sites were positive for Ancylostoma spp. and, with the exception of EPEIs and dog faeces, for Strongyloides spp. The prevalence of Ancylostoma spp. was 87.5% for CND samples, 74.29% for EMIEs, 63.64% for CLB, 61.76% for PS and 64.29% for dog's and 42.86% for cats at CCZ. The prevalence of Strongyloides spp. ranged from 14.29% (cats/CCZ) to 41.18% (PS). Cases of cutaneous larva migrans were reported during interviews. Thus, from the public health perspective, the risk of individuals that frequent recreational areas in the municipality, especially children, to be infected by helminth larvae is noteworthy, indicating the need to develop policies aimed at controlling this important zoonosis.

Resumo Amostras de solo colhidas em escolas municipais (ensino público/EMEI e privado/EPEI), clubes (CLB), praças públicas (PP), condomínios residenciais (CND) e de fezes de animais do Centro de Controle de Zoonoses (CCZ) do município de Votuporanga/SP, foram submetidas ao método Baermann para detecção de larvas de helmintos zoonóticos. Foram determinadas as taxas de prevalência dos nematódeos identificados, e os resultados confrontados pelos testes Exato de Fisher e Qui-quadrado. Atendimentos de casos de larvas migrans na população foram levantados em entrevistas realizadas em Unidades de Saúde da Família e em planos de saúde privados. Todos os locais apresentaram positividade para Ancylostoma spp. e, com exceção de EPEIs e de fezes caninas, para Strongyloides spp. Prevalência de Ancylostoma spp. foi verificada em amostras de CNDs (87,50%), EMEIs (74,29%), CLBs (63,64%), PPs (61,76%) e em fezes de cães e gatos do CCZ (64,29% e 42,86%, respectivamente). As prevalências de Strongyloides spp. variaram de 14,29% (gatos/CCZ) a 41,18% (PP). Atendimentos de casos de larva migrans cutânea foram relatados nas entrevistas. Portanto, ressalta-se o risco de frequentadores de áreas de lazer do município, especialmente crianças, de adquirirem infecção por larvas de helmintos, indicando a necessidade da elaboração de propostas de políticas voltadas ao controle dessa importante zoonose.

Investigation of the haemolytic effects of Ancylostoma ceylanicum: observations on infected dogs in vivo and human and dog blood in vitro.

Investigations into the probable role of haemolysins in the causation of hookworm anaemia have been undertaken in living infected dogs. Secondly, the effects of living hookworms and various worm products on erythrocytes in vitro have been assessed. In dogs infected with varying numbers of A. ceylanicum, severe microcytic anaemia developed in the most heavily infected animals six weeks after infection. Erythrocytes from the latter animals showed significantly greater autohaemolysis in the presence of added glucose. When serum bilirubin and methaemalbumin, plasma haemoglobin, urinary urobilinogin and osmotic fragility of their red cells were measured, however, no evidence of haemolysis was detected. Erythrocytes from these animals appeared normal under scanning electron microscopy. In in vitro studies varying concentrations of adult worm extract had no effect on the haemolysis of either dog or human erythrocytes in the presence or absence of glucose nor on their mechanical fragility. There was no increase in 51Cr release from dog or human labelled red cells when incubated with either adult worm extract or excretory/secretory products of worms. Living adult worms caused an increase in 51Cr release from human but not dog labelled erythrocytes. Thus, the role of haemolysins in the genesis of hookworm anaemia is minimal.

Studies on the Transmissibility of Pathogenic-Organisms to Liver by Larvae of Liver Fluke and Hookworm

In order to confirm whether the migrating larvae of parasites could carry pathogenic organisms into liver and cause hepatitis, a series of experiments has been carried out. The summary of the results is as follows: 1. Clonorchis sinensis A few of the excysted larvae of Clonorchis sinensis penetrated into the peritoneal cavity, but they could not penetrate the liver tissues. The artificially introduced Clonorchis sinensis in the tissues were all destroyed within 3-5 days. There was no manifestation of diffuse inflammatory changes due to the inoculation of the parasites, though the sampled micro-organisms, Staphylococcus aureus, were confirmed from the surrounding area. 2. Hookworm The larvae carried pathogenic organisms to liver tissues either by cutaneous or oral infection, but there was no manifestation of hepatitis due to the micro-organisms: In conclusion, it is indicated that liverfluke and hookworm may transmit pathogenic organisms to the liver during their migration.