Observations on the epizootiology of gasterophilus intestinalis and G. nasalis in horses in morocco

Abstract

Ninety four horses from the Settat region of Morocco were examined for Gasterophilus intestinalis and G. nasalis larvae. All the horses were infected with G. intestinalis and 89 with G. nasalis; the mean larval burdens were 219 and 153, respectively. Third instar larvae of both species were present throughout the year. Second instar larvae of G. intestinalis were absent in April and May and those of G. nasalis in April only. More than 50% of horses had total burdens of more than 300 larvae and 4% harboured more than 1000 larvae. Young horses had higher infections than older animals. The period of adult activity of G. intestinalis is from April to October, with a maximum in summer. Second instar larvae of G. intestinalis are present in peak numbers from July to January and the third instars are voided in the faeces mainly in spring and summer. Infection with G. nasalis starts sooner than that with G. intestinalis. Second instar larvae are present from May to December in peak numbers. During January to March, many second instars of G. nasalis were found trapped in nodules. © 1980, All rights reserved.