Sheep enteric cestodes and their influence on clinical indicators used in targeted selective treatments against gastrointestinal nematodes

Abstract

Clinical indicators such as diarrhoea (DISCO) or anaemia (FAMACHA © ) are used as a measure for targeted selective treatments against gastrointestinal nematodes (GIN). Enteric cestodes such as Moniezia may interfere directly with DISCO or indirectly with the FAMACHA © score. We investigated 821 Ouled Djellal rams naturally infected in a steppe environment (GIN alone, cestodes alone, GIN and cestodes) or not. The rams were treated with ivermectin 2 months before being slaughtered to reduce the impact of nematodes on the clinical scores; however, persistent or newly acquired GINs were not related to both scores. Of the non-infected rams ( n = 296), 26% identified as needing treatment against GIN using the FAMACHA score, and 34.5% using DISCO would have been thus selected. This implies that the clinical indicators used for the targeted selective treatment of gastrointestinal nematodes are not fully reliable when a low infection is recorded and may well be influenced by confounding factors. As expected, only DISCO was affected by cestode infection, and we suggest that the presence of Moniezia should also be taken into consideration.

Animal-Based Indicators for On-Farm Welfare Assessment in Sheep

“…The DISCO score was lower in healthy animals or those infected only with nematodes than in sheep infected with cestodes. It also correlated with the number of cestode but not nematode eggs per gram of faeces (EPG) [48]. According to Ref.…”

“…The FAMACHA© chart shows no interrelationship with faecal egg count, but has been shown to correlate with haematocrit [47] and, therefore, seems to be a valid indicator for Haemonchus sp. [48] as well as adult Fasciola hepatica and could be used to identify sheep with high established fluke burden [49]. However, the chart shows low sensitivity in growing lambs, with an accuracy level of only 50% in identifying lambs in need of treatment [50,51] and should not be used alone to control haemonchosis in young animals [52,53].…”

Molecular differentiation of Thysaniezia (Helictometra) giardi and Moniezia species based on 18s rRNA gene in small ruminants

“…Thysaniezia ovilla (T. giardia), Moniezia expansa, and Avitellina centripunctata have been shown to have incidence rates at 3.59% to 89.92% of the entire intestinal parasite infections in sheep (3,4). Small ruminants have a prominent role for being socially, economically, and politically significant at national and international levels for disease control and prevention.…”