Pediculosis capitis and scabies are hyperendemic in the study areas and are associated with considerable morbidity. There is an urgent need to develop control measures for these parasitic skin diseases in resource-poor communities. This is the first community-based study describing in detail the epidemiology and morbidity of scabies and head lice infestation in Brazil.

Tungiasis is a zoonotic ectoparasitosis caused by the sand flea Tunga penetrans L. (Siphonaptera: Tungidae). This disease is hyperendemic in poor communities of north-east Brazil, causing considerable morbidity in affected human populations, but the animal reservoirs have not been investigated previously in Brazil. To assess the prevalence and intensity of T. penetrans infection in domestic and peri-domestic animals, as well as in the human population, we surveyed two typical communities of north-east Brazil: an urban slum and a traditional fishing village. In the slum we examined 849 humans, 121 cats, 82 dogs, 2 pigs, 2 rabbits, 1 monkey and 56 rodents, comprising 34 rats (Rattus rattus L.) and 22 mice (Mus domesticus L). In the fishing village we examined 505 humans, 68 dogs, 37 cats, 7 donkeys, 4 cattle, 3 pigs and 1 monkey. Tungiasis was common among dogs and cats of both communities, with respective prevalence rates of 67.1% (95% CI: 55.8-77.1) and 30.9% (95% CI: 20.2-43.3) in dogs, 49.6% (95% CI: 40.4-58.8) and 32.4% (95% CI: 18.0-49.8) in cats. Slum rats were 41.2% (95% CI: 24.6-59.3) infested, but the other animals were not. Human prevalence rates were 54.4% (95% CI: 51.0-57.8) in the slum and 52.1% (95% CI: 47.6-56.5) in the fishing village. High prevalence rates (range 31-67%) of tungiasis in humans, pets and rats (but apparently not other animals) indicate the need for an eco-epidemiological approach to control of this anthropo-zoonotic problem.

Tungiasis is a neglected parasitic skin disease caused by penetration of female sand fleas into the epidermis. The ectoparasitosis is widespread in resource-poor communities in South America, the Caribbean and sub-Saharan Africa. To identify risk factors for the presence of sand fleas and severe infestation in an endemic community, we examined the entire population of a traditional fishing village for the presence of embedded sand fleas and determined the number and type of lesions. Demographic, behavioural and environmental characteristics of the population were assessed using a structured questionnaire. Multivariable analysis showed that both occurrence of tungiasis and heavy infestation were significantly related to poor housing conditions (odds ratio [OR]=4.7, 95% CI 1.4-15.8), lack of health education (OR=4.1, 95% CI 2.0-8.6) and presence of animals on the compound (OR=1.9, 95% CI 1.1-3.4). Contrary to common belief, a protective effect of frequent use of closed footwear could not be demonstrated. Based on the population attributable fractions calculated for the major risk factors identified, we conclude that several low-cost interventions would have a considerable impact on the occurrence of tungiasis and heavy infestation.

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Tungiasis (caused by the sand flea Tunga penetrans) is hyperendemic in many resource-poor communities in Brazil. To understand transmission dynamics of this parasitic skin disease in a typical endemic area, a longitudinal study was carried out in a slum in Fortaleza in northeastern Brazil. In a door-to-door survey, the population of a randomly selected area (n = 1,460) was examined on four occasions for the presence of embedded sand fleas. Prevalence rates were 33.6% in March (rainy season), 23.8% in June (end of the rainy season), 54.4% in September (peak of the dry season), and 16.8% in January (begin of the rainy season). Tungiasis was more common in males than in females. The intensity of infestation was correlated with the prevalence. The study shows that prevalence of tungiasis and parasite burden vary significantly during the year with a peak in the dry season. These findings have important consequences for the design of control measures.

Abstract. Tungiasis is caused by the penetration of the female sand flea Tunga penetrans into the epidermis. It is generally assumed that lesions are confined to the feet. To determine to what degree tungiasis occurs at other topographic sites, 1,184 inhabitants of a poor neighborhood in northeastern Brazil were examined; 33.6% were found to have tungiasis (95% confidence interval ‫ס‬ 30.9-36.4%). Six percent presented lesions at locations other than the feet, with the hands being the most common ectopic site (5.5%). Other sites were the elbows, thighs, and gluteal region. Ectopic tungiasis was significantly associated with the total number of lesions (P < 0.001) and an age less than 15 years old (P ‫ס‬ 0.02). In 86 patients actively recruited with lesions on their feet, ectopic localizations were observed in 25.6%. Since untreated sand flea lesions are prone to become superinfected, clinicians should be aware of not missing any ectopic localization of tungiasis.

SummaryEctoparasitic diseases are endemic in many poor communities in north-east Brazil, and heavy infestation is frequent. We conducted two studies to assess disease perception and health care seeking behaviour in relation to parasitic skin diseases and to determine their public health importance. The first study comprised a representative cross-sectional survey of the population of a slum in north-east Brazil. Inhabitants were examined for the presence of scabies, tungiasis, pediculosis and cutaneous larva migrans (CLM). The second study assessed health care seeking behaviour related to these ectoparasitoses of patients attending a Primary Health Care Centre (PHCC) adjacent to the slum. Point prevalence rates in the community were: head lice 43.3% (95% CI: 40. Only 28 of 54 patients with scabies, three of 55 patients with tungiasis, four of six patients with CLM and zero of 110 patients with head lice sought medical assistance. The physicians of the PHCC only diagnosed a parasitic skin disease when it was pointed out by the patient himself. In all cases patients were correctly informed about the ectoparasitosis they carried. The results show that tungiasis and pediculosis, and to a lesser extent scabies and CLM, are hyperendemic but neglected by both population and physicians, and that prevalence rates of tungiasis and scabies at the PHCC do not reflect the true prevalence of these diseases in the community.

Tungiasis is hyperendemic in many poor communities in Brazil and is associated with considerable morbidity. In order to understand the factors that determine the distribution of this ectoparasitosis in a rural community, an epidemiological study was carried out in a traditional fishing village in Ceará State, north-eastern Brazil. Based on active case detection and voluntary participation, 91% of the population (belonging to 95% of all families) was examined. Embedded fleas were looked for over all parts of the body, counted, and the lesions were staged. The overall prevalence of infestation was 51.3% (95% CI: 47.0-55.5). More males than females were infested (54.8% vs 48.3%); however, this difference was not statistically significant. Age-specific prevalence rates followed an S-shaped curve with peaks in children aged 5-9 years and people elder than 60 years. The parasite burden was high (range 1-145 lesions; arithmetic mean: 8.9) and particularly elevated in males, children <15 years and the elderly. The distribution of the parasite burden was uneven within the population with the majority of the lesions in a few individuals: the 23 subjects (8% of all infested) with severe infestation (>30 lesions) accounted for 1,366 of the 2,493 lesions (54.8%) documented. The study shows that tungiasis is a highly prevalent ectoparasitosis in this deprived community with a peculiar distribution of prevalence and parasite burden.