Small-Lungworm (Protostrongylidae) Infections in Relation to Meat Sheep Breeds, Mediterranean Climates, and Anthelmintic Regimens

Protostrongylid nematodes (small lungworms) are very common in Mediterranean sheep and have long been recorded in North Africa. Here, the following four species are found: <i>Muellerius capillaris</i>, <i>Neostrongylus linearis</i>, <i>Cystocaulus ocreatus</i>, and <i>Protostrongylus rufescens</i>. Previous risk factors studies for protostrongylids have been conducted in a single farm and therefore have limitations. Sixty-one meat sheep farms in north-eastern Algeria were surveyed for protostrongylid infection and anthelmintic treatment in late autumn/early winter. The climates of the nine regions ranged from subhumid to arid for humidity and from mild to cool for winter temperature. The highest infection, estimated by the number of larvae per gram of faeces (LPG), was found in subhumid and semi-arid climates. The Rembi breed was more infected than the Ouled Djellal or their crosses. LPG decreased with increasing number of treatments. The latter was also associated with an increased percentage of <i>M. capillaris</i> and a decrease in species diversity. The anthelmintic regimen (ivermectin, levamisole, and albendazole) directly targets gastrointestinal nematodes and indirectly protostrongylids. The use of effective drugs targeting protostrongylids at key moments may provide more effective control.