Echinococcus granulosus/Cystic Echinococcosis is a zoonotic disease that is distributed worldwide. The larval (cystic) stage is a life-threatening infection that develops mainly in lungs and livers of humans. The disease is highly endemic in sheep-raising countries where dogs are used to guard the herds. People may remain asymptomatic for many years; however, once the space-occupying signs appear people may require operation and/or long-term use of antiparasitic drugs.
We carried out a cross-sectional survey in humans in a remote area in the Central Peruvian Highlands and demonstrated a prevalence of liver cysts of 4.7% (45/949) with portable ultrasound, a lung cyst prevalence of 1.1% (9/829) by means of chest radiograph, and serological prevalences of 8.9% (83/929) using an immunoblot test (crude hydatid cyst fluid) and 19.5% (184/929) using the recombinant antigen rEpC1-GST. When serological results were compared with Cystic Echinococcosis-image positive results their sensitivities were less than 50% for both hepatic and pulmonary cysts.
A field trial of treatment in sheep was also performed. We did not find any significant effect against hydatid cyst of Nitazoxanide alone or combination Nitazoxanide with Oxfendazole. However, Oxfendazole at 30mg/kg for 11 consecutive weeks showed efficacies of 61% and 100% in killing protoscoleces in lung and liver cysts, respectively. In the second field trial, the regimens of Oxfendazole at 60mg/kg weekly for 4 weeks, combination Albendazole plus Praziquantel, and combination Oxfendazole plus Praziquantel for 6 weeks all had statistically higher proportions of cured or improved sheep as compared to the placebo group (from 88.9% to 93.8% vs. 50% placebo). In summary, we demonstrated a high prevalence of Cystic Echinococcosis in 9 rural villages in the Central Andes, and the low performance of serological tests when used under field conditions. Meanwhile, Oxfendazole either alone or combined with Praziquantel might be an alternative strategy to include in control programs when combined with other measures such as dog or sheep vaccination. Further studies are needed to elucidate the most appropriate dosages or even its future application against human Cystic Echinococcosis.
|Advisor:||Gilman, Robert H.|
|School:||The Johns Hopkins University|
|School Location:||United States -- Maryland|
|Source:||DAI-B 70/04, Dissertation Abstracts International|
|Subjects:||Public health, Parasitology, Epidemiology|
|Keywords:||Chemotherapy, Cystic echinococcosis, Echinococcus granulosus, Nitazoxanide, Oxfendazole, Zoonotic diseases|
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