Analysis of the Index of Host Specificity in Metazoan Parasites of Peruvian Fish

Abstract

Host specificity, which reflects the number of hosts a parasite can infect, is a key concept in disease ecology due to its connection with zoonotic parasites. This study assessed the specificity of metazoan parasites in marine and freshwater fish from Peru using indices such as STD, VarSTD, STD*, and βSPF. The results showed that parasites like Lecithocladium cristatum and Helicometra fasciata have low specificity (STD ≈ 5), whereas Procamallanus (Spirocamallanus) pintoi, Proleptus carvajali, and Lernanthropus huamani exhibit high specificity. The lack of correlation between the number of hosts and the indices indicates that specificity depends more on adaptation to the host than on the number of infected species.This study, the first to apply IHS indices for aquatic parasites in Peru, lays the groundwork for future research and underscores their ecological importance.