Schistosomiasis: A Neglected Tropical Parasitic Disease of Public Health Concern

The neglected diseases, which involve diverse etiological agents, such as viruses (chikungunya, dengue, rabies), bacteria (anthrax, bovine tuberculosis, brucellosis, leprosy, leptospirosis, plague), fungi (chromoblastomycosis), protozoa (leishmaniasis, malaria, trypanosomiasis), helminthes (dracunculiasis, echinococcosis, lymphatic filariasis, onchocerciasis, schistosomiasis, taeniasis/cysticercosis), and ectoparasites (scabies) are important diseases from public health and economic point of view (۱,۲). These diseases are seen in both sexes, all age groups, and in all seasons. In addition, they are responsible for morbidity and mortality worldwide, especially in tropical and sub-tropical regions. According to the World Health Organization (WHO), about one billion people in ۱۹۸ countries are affected with neglected tropical diseases (۱). Neglected diseases are primarily reported in the underprivileged people of the society living in developing nations with insufficient medical facilities and poor environmental sanitation (۱,۲). Among these, schistosomiasis (bilharziasis and snail fever) is an acute and chronic tropical disease and a neglected helminthic zoonosis of global distribution. The recorded history of schistosomiasis goes back to the year ۱۸۵۱ when the German physician Theodor Bilharz first described it following an autopsy in Egypt (۱). Since then, schistosomiasis has been reported from Brazil, Burundi, Cambodia, China, Ghana, Iran, Japan, Jordan, India, Kenya, Laos, Mauritius, Middle East, Niger, Nigeria, Oman, Philippines, Puerto Rico, Rwanda, Saudi Arabia, Sierra Leone, Suriname, Tanzania, Thailand, Tunisia, Venezuela, and Yemen (۱,۳-۶). Over ۲۵۰ million people are estimated to have contracted the disease globally, with up to ۷۷۹ million still at risk of infection (۱,۴). Among African countries, Nigeria has the maximum number of schistosomiasis cases with about ۲۹ million infected people, among which ۱۶ million are children, and about ۱۰۱ million people are at risk of getting infected (۱).