Iraqi Journal of Veterinary Sciences, Vol. 22, No. 1, 2008 (5-7) Evaluation the effect of albendazole against nematodes in sheep in Mosul, Iraq E. K. Mohamed and M. I. Al-Farwachi
Department of Internal and Preventive Medicine, College of Veterinary Medicine, University of Mosul, Mosul, Iraq
(Received February 11, 2008; Accepted June 26, 2008)
Abstract
Six sheep farms in Mosul city, Iraq randomly selected, were surveyed for gastrointestinal nematodes resistant to
Albendazole. On each of 6 sheep farms, 20 lambs were randomly distributed into two equal groups untreated control group, and albendazole (benzimidazole) group (10 mg/kg BW). Faecal egg counts and larval cultures were done at 7, 14, and 21 days after anthelmintic treatment. Resistance was apparent for albendazole on 4 farms out of 6 (66.7%). Post-treatment larval cultures indicated: Strongyloides papillosus, Marshalligia marshalli, Nematodirus spathiger and Haemonchus contortus.
Keywords: Albandazole; Nematodes; Sheep Strongyloides papillosus Marshalligia marshalli Nematodirus spathigerHaemonchus contortus.
Introduction
first recognized by a clinical failure in response to
anthelmintic therapy and by the persistence of positive
Parasitism, and gastrointestinal nematode parasitism in
faecal egg counts, or the presence of worms following
particular, is arguably the most serious constraint affecting
treatment (3). Resistance to anthelmintics in a range of
small ruminant production worldwide. Eco-nomic losses are
sheep gastrointestinal helminths has been reported from
caused by decreased production, cost of prevention, cost of
several countries (4). Resistance has been reported most
treatment, and the death of infected animals (1).
frequently in Haemonchus contortus and it can involve
Intensification of animal production has led to an increasing
benzimida-zole, salicynilides, levamizole, morantel and
reliance on effective anthelmintic drugs to control helminth
ivermectin. In Europe, resistance in sheep nematodes has
diseases. Regular suppressive dosing of susceptible animals
been reported from several countries including France (5).
has been shown to result in the development of resistance in
Ivermectin resistant Haemonchus contortus in Louisiana
sheep nematodes (1,2). Resistance to anthelmintic is usually
lambs in U.S.A. (6), and benzimidazole resistant to
Iraqi Journal of Veterinary Sciences, Vol. 22, No. 1, 2008 (5-7)
stronglyes of sheep in Nigeria (7) have been reported. In
95%. Furthermore, in the above mentioned farm, the lower
Iraq, there are few reports of anthelmintic resistance in
limit of the 95% confidence intervals was 43.0 suggesting
gastrointestinal nematodes of small ruminants. The current
that virtually in all the farms, albendazole resistance
study was designed to examine resistance of nematodes to
nematodes occurred. (Anthelmintic resistance is suspected
albendazole in a sample of randomly selected sheep farms
when there is less than 80% reduction in nematodes egg
output following therapeutic dosage with anthlemintics). By
the criteria described, resistance was apparent for
Materials and Methods
albendazole on 4 farms out of 6 (66.7%). Post-treatment
indicated: Strongyloides papillosus,
Six sheep farms located in Mosul city (Iraq) were
Marshalligia marshalli, Nematodirus spathiger and
randomly selected for this study. Most of the sheep
Haemonchus contortus. The Strongyloides papillosus was
originated from the northern part of Mosul city. No history
the pre-dominant larval type in 3 farms, where as
of anthelmintic usage and other management procedures
Haemonchus contortus was the dominant genus in one farm
The general procedure to detect anthelmintic resistance
in nematodes was that recommended by the World
Table 1: Number (mean ± SE) for fecal egg count (egg per
Association for the Advancement of the Veterinary
gram), percentage of fecal egg count reduction
Parasitology (WAAVP) (8). None the tested animals had
(FECR) after treatment with albendazole (10
received any anthelmintic treatment for at least 6 weeks
prior to the start of the study. ON each of the six sheep
farms, 20 lambs from both sexes, 2 to 6 months old, were
selected, individually identified, and randomly distributed
into 2 equal groups. The untreated control group and
Albendazole group (Albendazole 2.5% suspension, Al-
Salam Factory for drug production, Baghdad, Iraq) given
Seven, 14 and 21 days after anthelmintic treatment,
Significantly different from day 0 value at p < 0.05.
individual faecal samples were taken once from all the
animals and processed for faecal egg counting by a
modified McMaster technique in which one counted egg
Table 2: Post treatment larval cultures (in %) in sheep
equated to 50 eggs per gram of faeces (epg) (9). The mean
faecal egg count for each treatment group (epg t) was
caculated and compared with that of control group (epg c).
The faecal egg count reduction (FECR) was determined using the formula (8):
According to WAAVP recommendations (8,10) resistance
1- The percentage reduction in egg count is less than 95%
2- The lower limit of the 95 % confidence intervals is less
On farms where anthelmintic resistance was detected, a
group larval culture was performed to assess the percentage
of nematode genera Strongyloides papillosus, Marshalligia marshalli, Nematodirus spathiger and Haemonchus Discussion contortus by counting at least 100 third-stage larva (L3).
The results of this study indicate that low levels of
albendazole are effective against nematdes of sheep in the 4
farms out of 6 sheep farms examined. Anthelmintic
The mean faecal egg count (FEC) and FEC reduction
resistance is suspected in these farms. However,
(FECRs) in Table 1. The mean reduction in egg counts after
benzimidazole resistance has been described earlier in
treatment with albendazole ranged from 21.0 to 72.3%, and
sheep farms in the many countries (11-13). The control of
all farms except farms 2 and 4 showed values lower than
nematode parasites traditionally relies on grazing
Iraqi Journal of Veterinary Sciences, Vol. 22, No. 1, 2008 (5-7)
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This study represents a portion of a diploma report
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