Can ruminants become infected with trematode parasites through irrigation?
Abstract
Shanti Lal Choubisa
Although several different species of digenetic trematode (fluke) parasites have been found to infect various species of vertebrates including humans and ruminants. However, the most common species of them are Fasciola spp., Amphistomum spp., Paramphistomum spp., and Schistosome spp. which mostly infect domestic ruminantslike cattle, water buffaloes, sheep, goats, and camels and cause various dangerous trematodiasessuch asfascioliasis, amphistomiasis, paramphistomiasis, and schistosomiasis, respectively. Every year, thousands of ruminants die due to infection of these trematode parasites or trematodiases, adversely affecting the herd owners and the country's economy. These diseases are spread among diverse species of ruminants by their specific vectors, snails (Gastropods: Mollusca) which are commonly found in various freshwater habitats like large ponds, lakes, dams, rivers, etc. In fact, these snails are the intermediate hosts of these trematode parasites and complete their life cycle. Actually, in snails, different larval stages of these trematodes such as sporocyst, radial, and cercarial develop. Among these larvae, cercarial larvae are active and free swimmers. After emerging from the snail, these larvae either penetrate the skin of animals (in case of schistosome trematodes) when they come in contact with water bodies or get deposited on the leaves of aquatic plants as cysts called metacercarial larvae which are highly infective and have amazing ability to survive even in unfavorable environments. During grazing, these metacercarial larvae enter the body of ruminants with food and eventually, they reach their target organs where they start growing and cause trematodiasis. This is a common cause of trematode infection in animals through reservoirs. But it is also possible that large numbers of domestic ruminants may become infected with trematodes simultaneously through irrigation. But this route of trematode infection is rarely known which is the main focus of the present editorial.