Distribution of lymneids and cercaric index of Fasciola hepatica in the Arequipa Region, Peru

Ayaqui R.; Ticona J.; Condo R.; Ruelas-Llerena N.; Pointier J.P. · Revista Veterinaria (2025) · DOI: 10.30972/vet.3628325

Resumen

Fasciolosis is a zoonotic disease caused by Fasciola hepatica, which is widely distributed in Peru and considered highly endemic in the Arequipa region. Despite this, records of lymnaeid snails in the area remain limited. This study aimed to identify lymnaeid vectors of F. hepatica and to determine their distribution across natural regions, along with their corresponding cercarial index (CI). Lymnaeid snails were manually collected from irrigation canals, wetlands, and other humid environments, identified by their small size and dextral coiling shell. A subset of 10–25 snails was immersed in water at 70°C for 30–40 seconds to facilitate soft tissue extraction. The soft bodies were then removed from the shells and preserved in 70% ethanol. Taxonomic identification was conducted at the Centre de Recherches insulaires et observatoire de L’environnement (CRIOBE), Université de Perpignan, France, based on morphological characteristics of the shell and soft body parts. Sampling locations were categorized according to natural regions: coast (≤2000 m.a.s.l.) and highlands (>2000 m.a.s.l.). Live lymnaeids were examined by compression under a compound microscope (40X and 100X magnification). The criterion for positivity was the presence of rediae and cercariae of F. hepatica. New distribution areas of lymnaeid snails were identified. On the coast, the species detected included Galba cubensis (primary vector) in the provinces of Caravelí, Camaná, Islay,and Arequipa; Pseudosuccinea columella (potential vector) in Caravelí; and G. schirazensis in Santa Rita de Siguas. In the highlands, G. truncatula was identified as the primary vector in the provinces of Caylloma, La Unión, Castilla, Condesuyos, and Arequipa. Cercarial indices were generally low, averaging 0.63% for the Arequipa region. In localities with positive vectors, the distribution was as follows: on the coast, G. cubensis in Vítor showed a CI of 2.13%; in the highlands, G. truncatula exhibited CI values of 1.20% in Huanca, 1.61% in Achoma, 2.63% in Maca, and 2.78% in Taurisma.

Instituciones: Universidad Nacional de San Agustín de Arequipa