MORPHOMETRY OF Fasciola hepatica COLLECTED FROM LIVERS OF TWO HOSTS IN CENTRAL TABASCO, MEXICO

Background. Fasciolosis is a zoonotic parasitic disease, which affects different ruminant and non-ruminant hosts from tropical and temperate regions around the world. There are reports that parasites of the genus Fasciola, particularly F. hepatica, show morphological variation according to the species of host animal in which it develops. Objective. To explore the morphometric variation of adults and eggs of F. hepatica collected in the liver of cattle and sheep in the central region of Tabasco, in the Mexican tropics. Methodology. A total of 207 adult parasites (96 from 11 cattle livers and 111 from seven sheep livers) were collected to determine their linear measurements, area, proportions of the body, suckers, and pharynx. Additionally, 384 eggs were measured (119 from sheep and 265 from cattle). Morphometric measurements were grouped by host for statistical comparisons. Results. The study found that the parasites of sheep hosts were, on average, larger than those found in bovine hosts. Preliminary findings showed that F. hepatica from bovine hosts produced, on average, more eggs than parasites from sheep hosts, even though the individuals were, on average, longer and wider than those collected from bovines. Morphometric measurements of the eggs from F. hepatica collected in the different hosts showed no differences. Implications. This type of variation could have implications on the host-parasite relationship that have an impact on animal health and parasitosis control. Conclusion. The present study shows the existence of variation in the size of F. hepatica adults and in the number of eggs they produce by naturally parasitizing two ruminant hosts in the same endemic area.