Oestrus ovis in sheep: relative third-instar populations, risks of infection and parasitic control

Authors

Guillaume Tabouret, UMR 959, Physiopathologie des Maladies Infectieuses et Parasitaires des Ruminants, École Nationale Vétérinaire
Philippe Jacquiet, UMR 959, Physiopathologie des Maladies Infectieuses et Parasitaires des Ruminants, École Nationale Vétérinaire, 23 chemin des Capelles, 31076 Toulouse Cedex, France
Philip Scholl, US Dept. of Agriculture, Agricultural Research Service
Philippe Dorchies, UMR 959, Physiopathologie des Maladies Infectieuses et Parasitaires des Ruminants, École Nationale Vétérinaire, 23 chemin des Capelles, 31076 Toulouse Cedex, France

Date of this Version

November 2001

Comments

Published in Vet. Res. 32 (2001) 525–531.

Abstract

Oestrus ovis (L.) (Diptera: Oestridae), the nasal bot fly, has a relatively short free-living life cycle outside of the host, and therefore it is necessary to know when the parasitic period occurs in order to prevent the clinical signs and economic losses caused by this parasite. The length of this parasitic portion of the life cycle is quite variable: a few weeks to several months depending on the season and climatic conditions. Surveys of Oestrus ovis larval populations in sheep show different results on the number of generations according to the local climate. Mean monthly larval profiles of L1 and L3 burdens of sheep from West African Sahelian countries, Mediterranean countries (Morocco, Tunisia and Sicily) and Southwest France were compared. Valuable information on the suspected extension of the fly season is obtained showing the period of infection in each area. This knowledge will be a valuable tool to help in choosing the right treatment at the right period.