Thomas Wilcke

Selective mass treatment with ivermectin to control intestinal helminthiases and parasitic skin diseases in a severely affected population.

OBJECTIVE To assess the short-term and long-term impact of selective mass treatment with ivermectin on the prevalence of intestinal helminthiases and parasitic skin diseases in an economically depressed community in north-east Brazil. METHODS An intervention was carried out in a traditional fishing village in north-east Brazil where the population of 605 is heavily affected by ectoparasites and enteroparasites. The prevalence of intestinal helminths was determined by serial stool examination and the prevalence of parasitic skin diseases by clinical inspection. A total of 525 people out of a target population of 576 were treated at baseline. The majority of these were treated with ivermectin (200 microg/kg with a second dose given after 10 days). If ivermectin was contraindicated, participants were treated with albendazole or mebendazole for intestinal helminths or with topical deltamethrin for ectoparasites. Follow-up examinations were performed at 1 month and 9 months after treatment. FINDINGS Prevalence rates of intestinal helminthiases before treatment and at 1 month and 9 months after mass treatment were: hookworm disease 28.5%, 16.4% and 7.7%; ascariasis 17.1%, 0.4% and 7.2%; trichuriasis 16.5%, 3.4% and 9.4%; strongyloidiasis 11.0%, 0.6% and 0.7%; and hymenolepiasis 0.6%; 0.4% and 0.5%, respectively. Prevalence rates of parasitic skin diseases before treatment and 1 month and 9 months after mass treatment were: active pediculosis 16.1%, 1.0% and 10.3%; scabies 3.8%, 1.0% and 1.5%; cutaneous larva migrans 0.7%, 0% and 0%; tungiasis 51.3%, 52.1% and 31.2%, respectively. Adverse events occurred in 9.4% of treatments. They were all of mild to moderate severity and were transient. CONCLUSION Mass treatment with ivermectin was an effective and safe means of reducing the prevalence of most of the parasitic diseases prevalent in a poor community in north-east Brazil. The effects of treatment lasted for a prolonged period of time.

The animal reservoir of Tunga penetrans in severely affected communities of north-east Brazil

Abstract.  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.

Parasitic skin diseases: health care-seeking in a slum in north-east Brazil.

Ectoparasitic 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: 40.5–46.3), tungiasis 33.6% (95% CI: 30.9–36.4), scabies 8.8% (95% CI: 7.3–10.6) and CLM 3.1% (95% CI: 2.2–4.3). Point prevalence rates of patients attending the PHCC were: head lice 38.2% (95% CI: 32.6–44.1), tungiasis 19.1% (95% CI: 14.7–24.1), scabies 18.8% (95% CI: 14.4–23.7) and CLM 2.1% (95% CI: 0.8–4.5). 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.

High prevalence of tungiasis in a poor neighbourhood in Fortaleza, Northeast Brazil

Tungiasis has been reported to occur in many Latin American, Caribbean and African countries. However, epidemiological data are still very scanty and do not exist at all for Brazil. To fill this gap, a cross-sectional study has been undertaken in a shantytown (favela) in Fortaleza, Ceará State, northeast Brazil. All 327 households of a circumscribed sub-area were visited, and 1185 out of the 1460 household members were thoroughly examined for the presence of tungiasis. Thirty-four% (95% CI: 30.9-36.4) were found to be infected with Tunga penetrans with a significant preponderance of the male sex (p<0.0001). In the children five to nine years old, the age group most heavily affected, the prevalence rate was 65.4% (95% CI: 54.0-75.7) in boys and in 48.3% (95% CI: 37.4-59.2) in girls. The data show that tungiasis is hyper-endemic in the study area. As the favela is typical for the many poor communities in northeast Brazil, it can be assumed that tungiasis is a frequent infection in the underprivileged in this part of the country.

Cutaneous larva migrans (creeping eruption) in an urban slum in Brazil

Background  Cutaneous larva migrans (CLM) is caused by the penetration of larvae of animal hookworms into the skin. Knowledge about this ectoparasitosis is mainly based on the examination of travelers or other expatriates. Population‐based studies in an endemic area have never been performed.

A simple method for rapid community assessment of tungiasis

Objective  To evaluate a rapid assessment method to estimate the overall prevalence of tungiasis and severity of disease in endemic communities.