Anthelmintic resistance in gastrointestinal nematodes of goats in southern Mozambique

Small ruminant production is significantly constrained by gastrointestinal parasites once they cause serious production and economic losses for both small-scale and large-scale farmers in the developing world. The control of helminth parasites is most exclusively based on the use of anthelmintics for the economic production of ruminants. However, the resistance of nematodes to the commonly used groups of anthelmintics represents a threat to the production, particularly for small ruminants. The objective of this study was to assess the efficacy of albendazole, the most frequently used anthelmintic in Gaza and Maputo provinces in the southern region of Mozambique, in gastrointestinal nematodes of goats between November and December, 2016. Eleven goat farms in Gaza (n = 5) and Maputo (n = 6) were surveyed. The faecal egg count reduction test was used to assess the efficacy of the drug. The flocks were considered resistant when the reduction in eggs per gram of faeces was less than 95% and the lower limit of the confidence interval was less than 90%. Resistance to albendazole was detected in 60% (3/5) of the farms in Gaza province and 83.3% (5/6) of the farms in Maputo province. The percentage of faecal egg count reduction varied from 51 to 97% in Maputo and from 0 to 100% in Gaza in the farms surveyed. In pre-treatment coprocultures, Haemonchus spp., Oesophagostomum spp. and Trichostrongylus spp. were the predominant nematode species. Post-treatment larval cultures indicated that Haemonchus spp. and, to a lesser extent, Oesophagostomum spp. and Trichostrongylus spp., were resistant to albendazole. This study provided further evidence that anthelmintic resistance of gastrointestinal nematode parasites in goats is currently a problem of great significance in this region of the country and that appropriate measures must be taken to reverse the situation. Key words: Albendazole, efficacy, gastrointestinal parasites, small ruminants, Mozambique.