A Multi-disciplinary Overview of Chagas in Periurban Peru

There are between 8 and 11 million cases of America Human Trypanosomiasis, commonly known as Chagas disease, in Latin America. Chagas is endemic in southern Peru, especially the Arequipa region, where it has expanded from poor, rural areas to periurban communities. This paper summarizes the findings of four studies in periurban Arequipa: on determinants of disease-vector infestation; on prevalence, spatial patterns, and risk factors of Chagas; on links between migration, settlement patterns, and disease-vector infestation; and on the relationship between discordant test results and spatially clustered transmission hotspots. These studies identified two risk factors associated with the disease: population dynamics and the urbanization of poverty. Understanding the disease within this new urban context will allow for improved public health prevention efforts and policy initiatives. Discovered in 1909 by Brazilian physician Carlos Chagas, American Human Trypanosomiasis is a chronic and potentially life-threatening illness found throughout Latin America (Moncayo, 2003). Indeed, it is estimated that there are between 8 and 11 million cases in Mexico and Central and South America (Centers for Disease Control [CDC], 2009). Chagas disease, as it is most commonly known, is endemic in southern Peru, especially in the region of Arequipa. Once thought to be limited to poor, rural areas, the disease is now appearing in the periurban communities that surround Arequipa City, the capital of the region (Cornejo del Carpio, 2003). Understanding the urbanization of Chagas disease will allow public health and medical professionals to better combat the further transmission of the disease. After providing an overview of Chagas and introducing the scope of the disease in Latin America, this paper will summarize the findings of four recent studies conducted in periurban districts in Arequipa. Ultimately, this paper seeks to identify the risk factors associated with Chagas infection in Arequipa’s periurban communities

Prevalence of soil transmitted nematodes on Nukufetau, a remote Pacific island in Tuvalu

BACKGROUND: The population of Nukufetau, a remote coral atoll island in Tuvalu in the Western Pacific, received annual mass drug administration (MDA) of diethylcarbamazine and albendazole under the Pacific Elimination of Lymphatic Filariasis program in 2001, 2002 and 2003, with the last MDA occurring six months before a cross-sectional survey of the whole population for soil transmitted helminths (STH). METHODS: A cross-sectional survey in May 2004 recruited 206 residents (35.2% of the population) who provided a single faecal sample that was preserved, concentrated and examined microscopically. RESULTS: Overall prevalence of STH was 69.9%; only hookworm and Trichuris trichiura were diagnosed. Trichuris was present in 68.4% with intensity of infection being light in 56.3%, medium in 11.7% and heavy in 0.5%. Hookworm occurred in 11.7% with intensity of infection 11.2% being light and medium in 0.5%. Twenty individuals (9.7%) had dual infections. The prevalence of Trichuris was constant across all ages while the prevalence of hookworm was significantly lower in residents below 30 years of age. In the age group 5–12 years comparison of results with a 2001 survey [1] suggested that the prevalence of STH has declined minimally, due to sustained high prevalence of Trichuris, while hookworm has declined dramatically from 34.4% to 1.6%. CONCLUSION: The results of this survey suggest that although the MDA appears to have reduced hookworm prevalence in residents below 30 years of age, there has been minimal effect on Trichuris prevalence. An integrated program to control STH is required

Randomized Clinical Trial on Ivermectin versus Thiabendazole for the Treatment of Strongyloidiasis

Strongyloidiasis is the infection caused by the worm Strongyloides stercoralis. Due to its peculiar life cycle Strongyloides may remain indefinitely in the host, if not effectively cured. Although the disease is usually mild, in case of weakening of the host's immune defenses the worm may invade virtually all organs and tissues (disseminated strongyloidiasis, almost invariably fatal). The treatment must then reach the goal of the complete elimination of the parasite. Small size clinical trials showed similar, high efficacy of the two drugs ivermectin (used as a single dose) and thiabendazole (used twice daily for two consecutive days). All trials used as the criterion for cure the absence of larvae in stool exams. The latter however may easily miss the infection, falsely suggesting that the infection has been cured. This trial, using a test detecting specific Strongyloides antibodies as an additional and more sensitive diagnostic tool, confirms previous reports: the two drugs have similar efficacy but ivermectin is better tolerated and is therefore the first choice. However the cure rate was lower than 70% for the standard, single dose. The authors then conclude that a larger, multi center trial is needed to find the optimal dose schedule of ivermectin

Impact of Long-Term Treatment with Ivermectin on the Prevalence and Intensity of Soil-Transmitted Helminth Infections

Soil-transmitted helminth (intestinal worm) infections are very common in developing countries and are an important cause of illness. Mass de-worming treatments of school children are an important strategy to reduce illness caused by these infections in communities without access to clean water and sanitation. Few studies have examined the effect of repeated mass treatments in the long-term in controlling these infections. The objective of the present study was to assess the impact of the drug ivermectin used for the control of onchocerciasis (river blindness), that has important effects against intestinal worms, on the epidemiology of intestinal worms in children when administered repeatedly for 15–17 years. We compared the epidemiology of infections between children living in communities that received ivermectin with communities that never received the drug. The data suggest that ivermectin has important differential effects on intestinal worms with a greater impact on infections with Trichuris trichiura and little impact on Ascaris lumbricoides and hookworms infections. Our data suggest that long-term ivermectin treatments may provide health benefits through effects on T. trichiura infections but that the addition of second de-worming drug such as albendazole may be required for the control of other intestinal worm infections

Tribendimidine and Albendazole for Treating Soil-Transmitted Helminths, Strongyloides stercoralis and Taenia spp.: Open-Label Randomized Trial

More than a billion people are infected with intestinal worms and, in the developing world, many individuals harbor several kinds of worms concurrently. There are only a handful of drugs available for treatment, and drug efficacy varies according to the worm species. We compared the efficacy of a single oral dose of tribendimidine, a new broad-spectrum worm drug from China, with the standard drug albendazole for the treatment of hookworm, large roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura) and, for the first time, Strongyloides stercoralis and tapeworm (Taenia spp.). Our single-blind randomized trial was conducted in a village in Yunnan province, southwest China. Both drugs showed high efficacy against A. lumbricoides and a moderate efficacy against hookworm. Among 57 tribendimidine recipients, the prevalence of S. stercoralis was reduced from 19.3% to 8.8%, and that of Taenia spp. from 26.3% to 8.8%. Similar prevalence reductions were noted among the 66 albendazole recipients. Taking into account additional infections only discovered at treatment evaluation, the difference between the drug-specific Taenia spp. net cure rates was highly significant in favor of tribendimidine. In view of our promising results, multiple-dose schedules with tribendimidine against S. stercoralis and Taenia spp. should be evaluated next

Epidemiological role of humans, dogs and cats in the transmission of Trypanosoma cruzi in a central area of Argentina

Trypanosoma cruzi prevalence rates of human, dog and cat populations from 47 households of 3 rural localities of the phytogeographical Chaqueña area of Argentina were determined both by serological and xenodiagnostic procedures. Human prevalence rates were uniform and ranged from 49.6 to 58.7%. Overall prevalence rate in dogs (75.0%) was significantly higher than in humans (51.0%). The overall proportion of parasitemic individuals assessed by xenodiagnosis was significantly higher in either dog (64.2%) or cat (63.6%) populations than among humans (12.5%). Although both the average number of resident as well as infected individuals per household was higher for people than for dogs (6.5 vs. 3.3, and 3.4 vs. 2.4, respectively), the reverse was recorded when parasitemic individuals were considered (1.0 vs. 2.1). Results are discussed in relation to dog between dogs and people, and dogs and bugs. In the light of present data, dogs must be considered as the major donors of parasites to vector bugs and thus, principal contributors to transmission in this region of Argentina

Paragonimosis in the Cajabamba and Condebamba districts, Cajamarca, Peru Paragonimíase nos distritos de Cajabamba e Condebamba, Cajamarca, Peru

Stool samples from 409 pre-school and school students, living in six villages of the Cajabamba and Condebamba districts, Cajamarca, Perú, were examined using wet preparations and Lumbreras' method, looking for Paragonimus eggs. Fecal and sputum samples from two children (0.5%) of 6 and 8 year-old showed eggs of Paragonimus. One hundred and twenty freshwater crabs, Hypolobocera chilensis eigenmanni, were collected from the Condebamba valley and 21 (17.5%) of them were infected with P. mexicanus (syn. P. peruvianus) metacercariae. Our results show the persistence of Paragonimus in human beings and in the main source of infection, the crabs.<br>As amostras de fezes de 409 pré-escolares e escolares de 6 localidades dos distritos de Cajabamba e de Condebamba, departamento de Cajamarca, Peru, foram avaliados pelo método de Lumbreras na busca de ovos de Paragonimus sp. Dois meninos (0,5%), de 6 a 8 anos de idade, revelaram ovos de Paragonimus sp. nas suas fezes, bem como nas amostras de escarro. O exame radiográfico de tórax mostrou lesões pulmonares. Foram coletados 120 caranguejos de rio, Hypolobocera chilensis eigenmanni, no vale de Condebamba , encontrando-se 21 (17,5%) infectados com metacercárias de P. mexicanus (sin. P. peruvianus). Nossos resultados revelam a persistencia de Paragonimus sp. na população na sua principal fonte de infecção, os caranguejos

Household factors associated with the presence of human hydatid disease in three rural communities of Junin, Peru.

Introducción. La hidatidosis, zoonosis producida por el estadio larvario de la taenia Echinococcus granulosus, es un problema de salud pública a nivel nacional, en especial en aquellas regiones dedicadas a la crianza de ganado. A la fecha, se han descrito factores, a nivel individual, asociados con la infección por E. granulosus; sin embargo, no se encontró reporte previo que explore la asociación entre características de la vivienda y la presencia de esta enfermedad en alguno de sus miembros. Objetivos. Explorar la asociación entre las características de la vivienda y la presencia de hidatidosis entre las personas que la habitan. Materiales y métodos. Se realizó un estudio transversal en viviendas de tres comunidades rurales de Junín. Se evaluó el grado de asociación entre las características de la vivienda y la presencia de hidatidosis en el hogar mediante un análisis de regresión logística múltiple (RLM). Resultados. De un total de 417 viviendas evaluadas, 56 (13%) de ellas tenían al menos un caso positivo entre sus miembros; luego del análisis de RLM se observó que aquellas viviendas con más de tres miembros, localizadas en la comunidad con quintil de pobreza más bajo, que refirieron crianza de animales, y con una cobertura de evaluación mayor al 25% presentaron una mayor probabilidad de tener al menos un caso de positivo entre sus miembros. Conclusión. Las características observadas deben ser tomadas en cuenta para la determinación preliminar de subgrupos de alto riesgo, optimizando así el uso de los recursos y mejorando la eficacia de los programas de despistaje