Prevalence, infection intensity and seasonal variation of helminths in calves in the state of Piauí, Brazil

Abstract

An epidemiological study of gastro-intestinal helminths of crossbred Zebu calves was carried out in Campo Maior, PI, Brazil, from August 1977 to August 1979. Monthly data of faecal egg counts (EPG), coproculture and necropsies were obtained from 25 calves aging 9 to 12 months and 25 calves aging 20 to 24 months, naturally infected. The parasite helminths identified were Cooperia punctata, C. pectinata, C. curticei, Haemonchus contortus, H. similis, Oesophagostomum radiatum, Trichostrongylus axei, T. colubriformis, Trichuris discolor, Bunostomum phiebotomum, Capillaria bovis, Strongyloides papillosus, Moniezia benedeni, Setaria cervi, Paramphistomum spp. and Dictyo-caulus viviparus. The helminths having higher intensity and frequency averages were, respectively: C punctata (6,655 and 98%) C. pectinata (2,581 and 74%), H. contortus (1,341 and 90%), H. Similis (952 and 94%), T. axei (2,123 and 88%),and O. radiatum (315 and 94%). EPG data indicated increased levels of infection by Strongyloidea rainy season. Larvae of Haemonchus sp. were the most numerous, but individuals of the genus Cooperia predominated in the adult population. Necropsy findings showed that the calves were parasited by helminths year around.