Prevalence and seasonal changes in the population of gastrointestinal nematodes of small ruminants in the semi-arid zone of north-eastern Nigeria

https://doi.org/10.1016/j.vetpar.2006.09.004Get rights and content

Abstract

A survey was carried out to determine the prevalence and seasonal abundance of the egg and adult stages of nematode parasites of sheep and goats in the semi-arid zone of north-eastern Nigeria between January and December 2002. Faecal samples collected from 102 sheep and 147 goats and examined by the modified McMaster technique using saturated solution of sodium chloride as the floating medium revealed that 44 (43.1%) and 82 (55.8%) of the samples, respectively, contained at least one nematode egg type. Three nematode egg types were recovered with strongyle egg type (22.5% in sheep and 35.4% in goats) being the most prevalent followed, respectively, by Trichuris (5.9% in sheep and 4.1% in goats) and Strongyloides (4.9% in sheep and 4.1% in goats) egg types. Mean faecal egg counts were generally moderate in both sheep (1052 ± 922 strongyle, 1000 ± 590 Strongyloides and 380 ± 110 Trichuris eggs, respectively, per g of faeces) and goats (2092 ± 3475 strongyle, 958 ± 854 Strongyloides and 683 ± 512 Trichuris eggs, respectively, per g of faeces) and showed the same trend irrespective of the age or sex of the animals. The prevalence and counts of strongyle nematode eggs showed a definite seasonal sequence that corresponded with the rainfall pattern in the study area during the period. In both sheep and goats, counts of strongyle egg type increased with the rains and reached peak levels at about the peak of the rainy season in September. The other egg types encountered during the study did not show much variation with the season of the year. Out of the 45 sheep and 75 goats examined at necropsy, 27 (60%) and 39 (52%), respectively, contained adult nematode species. Seven genera of adult nematodes including Strongyloides, Trichostrongylus, Haemonchus, Trichuris, Cooperia, Oesophagostomum and Bunostomum species were encountered during the study. Bunostomum species were recorded only in sheep. Adult worm burdens were generally low and showed seasonal variation that corresponded with the rainfall pattern in the study area during the period. Haemonchus and Trichostrongylus species attained peak counts together in both goats (June) and sheep (August). Strongyloides species were encountered throughout the year in both sheep and goats irrespective of the season. Other genera of nematodes encountered occurred in very low numbers and did not allow any meaningful comparison of seasonal sequence. The results suggest that Haemonchus, Trichostrongylus and Strongyloides species may be the major contributors to small ruminant helminthiasis in the study area.

Introduction

Domesticated small ruminants, especially sheep and goats, constitute an important source of animal protein to many Nigerians. A lot of socio-economic importance is therefore attached to ownership of these animals that, in some cases, may be the only realizable wealth of a rural household (Mathewman, 1977, Omeke, 1988). Helminthiasis, especially parasitic gastro-enteritis (PGE) constitutes a serious health problem and limitation to the productivity of small ruminants in Nigeria due to the associated morbidity, mortality and cost of treatment and control measures (Anosa, 1977, Chiejina, 1987, Nwosu et al., 1996a, Nwosu et al., 1996b).

Parasitic gastro-enteritis is widely distributed in Nigeria and the prevalence and seasonal changes in the abundance of the causative parasites have been studied and reported from some geographical zones of the country (Chiejina, 1986, Nwosu et al., 1996a, Nwosu et al., 1996b). However, information is lacking on the situation in the semi-arid and arid zones of north-eastern Nigeria that produce over 30% of the small ruminant livestock in the country (Anon., 1980, Nwosu and Srivastava, 1993). This study was therefore designed to provide preliminary information on the prevalence and seasonal abundance of gastrointestinal nematode parasites of sheep and goats in the semi-arid zone of north-eastern Nigeria.

Section snippets

Study area and animals

The study was conducted between January and December 2002 in three local government areas (Jere, Konduga and Maiduguri metropolitan) of Borno state within the semi-arid zone of north-eastern Nigeria. The area with a mean annual rainfall of 553 mm usually has a short rainy season from June to September followed by a prolonged dry season for the rest of the year (Hess et al., 1995, Maryah, 2005). Sheep and goats of various breeds, sexes and age groups used for the study were randomly selected from

Results

Out of the 102 sheep and 147 goats examined in small-holder farms during the study period, 44 (43.1%) and 82 (55.8%) were, respectively, shedding nematode eggs in their faeces (Table 1, Table 2). The nematode egg types recovered from both sheep and goats were those of strongyles, Trichuris and Strongyloides species. Faecal egg counts were generally moderate in both sheep and goats and showed the same trend irrespective of the age and sex of the animals. Among the three nematode egg types

Discussion

The results of the faecal examination during the study revealed that only 43.1% of the sheep and 55.8% of the goats maintained under natural conditions in small-holder farms in the semi-arid zone of north-eastern Nigeria harboured gastrointestinal parasites during the period. The results also showed that strongyle egg type was the most prevalent. This agrees with previous reports from other geographical regions of Nigeria (Chiejina, 1986, Nwosu et al., 1996a, Nwosu et al., 1996b). In contrast,

References (20)

  • T.M. Hess et al.

    Rainfall trends in the north east arid zone of Nigeria 1961–1990

    Agric. Forest Meteorol.

    (1995)
  • J.W. Adams et al.

    Gastro-intestinal parasites of farm animals in eastern Nigeria

    Vet. Rec.

    (1966)
  • Anon.

    Manual of Veterinary Parasitological Laboratory Techniques. Technical Bulletin No. 18

    (1977)
  • Anon., 1980. Borno State Livestock Population, Annual Veterinary Report. Ministry of Animal and Forestry Resources,...
  • V.O. Anosa

    Haematological observations on the helminthiasis caused by Haemonchus contortus in Nigerian dwarf sheep

    Trop. Anim. Health Prod.

    (1977)
  • S.N. Chiejina

    The epizootiology and control of parasitic gastro-enteritis of domesticated ruminants in Nigeria

    Helminth. Abst. (Ser. A)

    (1986)
  • S.N. Chiejina

    Parasitic gastroenteritis in cattle and small ruminants: pathogeneis, diagnosis and treatment

    Zariya Vet.

    (1987)
  • J.P. Fabiyi

    An investigation into the incidence of goat helminth parasites in the Zaria area of Nigeria

    Bull. Anim. Health Prod. Afr.

    (1970)
  • B.B. Fakae

    The epidemiology of helminthasis in small ruminants under the traditional husbandry system in eastern Nigeria

    Vet. Res. Commun.

    (1990)
  • J. Hansen et al.

    The Epidemiology Diagnosis and Control of Gastro-intestinal Parasites of Ruminants in Africa

    (1990)
There are more references available in the full text version of this article.

Cited by (0)

View full text