Epidemiology of Human Fascioliasis Outbreaks in Iran

The increase in number of human fascioliasis and its outbreaks in the last two decades have changed the status of fascioliasis from a zoonosis to an immerging health problem. The infection is found in 61 countries where 160 million peoples are at risk. Fasciola infection in livestock may be found in some parts of Iran with various infection rates in cattle. As the human infection was rarely reported with patchy distribution in some provinces of Iran, the condition was changed since 1989 when the first outbreak of human fascioliasis occurred in Gilan Province located in north of Iran where about 10,000 people found infected and total number of infected cases estimated to be 2465. The contributing factors of the outbreak were higher number of rainfalls, using the infested water and high consumption of wild aquatic plants in infested areas. Various methods applied for identification of Fasciola species leading to human infection in infected areas revealed that three species of Fasciola, namely, F. hepatica, F. gigantica and a hybrid of the two species the causes of infection. The role of local snails in transmission of the infection was determined and using the serodiagnostic methods for future epidemiological survey was recommended.