Echinococcus granulosus infection in humans and livestock in the Coquimbo region, north-central Chile.

Cyst echinococcosis (CE) is one of the most important zoonosis in Chile, where studies have focussed mainly in moist southern regions. The present study was conducted to determine the prevalence of cystic echinococcosis (CE) in livestock and humans in the semiarid Coquimbo region in north-central Chile. A review of all surgical cases of CE in humans reported in the Elqui, Limarí and Choapa provinces in Coquimbo region for the period comprising 1995-2006 was obtained. In addition, a retrospective study of CE covering condemnation records from slaughterhouses of these provinces from the same period was carried out. The surgical incidence of CE in humans ranged between 2.3 and 8.5 cases per 10(5) people, with more cases reported in provinces with a higher percentage of rural inhabitants (Limarí and Choapa). A total of 174,034 cattle, 22,208 goats, 35,404 sheep, 25,355 swine and 9391 equines were examined during the period. Higher prevalence of CE was detected in cattle (24%), followed by swine (14%), sheep (11%), goats (6%), and equines (9%). More cases of CE in livestock were also found in provinces with higher rural population. The overall trend of the prevalence of CE for each livestock species across years was a significant downward one, except for swine in Elqui and sheep and swine in Choapa. Cattle showed higher prevalence of CE in liver in Elqui, in kidney in Limarí and in lungs in Choapa. Swine showed similar prevalence by organs in all provinces. Sheep showed higher prevalence of CE in liver in Elqui and Limarí and lower prevalence in Choapa. Goats presented higher prevalence of CE in kidney in all provinces, and equines had higher prevalence of CE in liver in the provinces where animals were slaughtered. Further studied are needed to assess whether these differences are due to different strains affecting these species or due to ecological factors. When analyzing the CE prevalence of each species within each province, a negative correlation between prevalence of CE in goats and rainfall in the Limarí province was found. This could be attributed to changes in management practices and/or ecological factors. This study shows that surveillance of CE at slaughterhouses combined with the analyses of incidence in humans can be used to detect areas with a higher risk of infection. Improvements in record-keeping of infected animals at slaughterhouses are proposed in order to trace back farms where infection was most likely acquired.

Echinococcus granulosus infection in domestic dogs in urban and rural areas of the Coquimbo region, north-central Chile.

Hydatidosis is a zoonotic disease caused by the cystic stage of the cestode parasite Echinoccocus granulosus, in which the definitive hosts are mainly domestic dogs. This parasite is regarded mainly as a rural disease, where man is exposed through contact with eggs excreted by definitive hosts; however, some studies have shown that domestic dogs can get infected within urban areas. This study was conducted to assess differences in prevalence of E. granulosus in urban and rural sites in Coquimbo region of Chile. From 2005 to 2006 a cross-sectional household questionnaire survey was conducted in Coquimbo and Ovalle cities, in three towns and in rural sites along two transects from these cities to the Fray Jorge NP in the Coquimbo region. Faecal samples were collected from dogs during the questionnaire survey and tested for Echinococcus coproantigens. Positive dogs were found in urban areas. Analysis of risk factors indicated that dogs inhabiting the borders of urban areas were at greater risk of being coproantigen positive than those in the centre of these areas. These results are likely to be related to the custom of slaughtering livestock at home in urban areas during local celebrations, which could favour the importation of E. granulosus to urban areas by acquiring livestock contaminated with cysts from rural sites. This study shows that surveillance and control measures in livestock and domestic dogs need to be introduced in urban areas as well as rural areas of the Coquimbo region to reduce the public health risk of hydatid disease.