Some risk factors for reproductive failures and contribution of Toxoplasma gondii infection in sheep and goats of Central Ethiopia: A cross-sectional study
Introduction
Ethiopia possesses about 26.1 million sheep and 21.7 million goats raised in various agro-ecological zones (Central Statistical Authority, 2008) and accounting for about 90% of the live animal/meat and 92% of skin and hides (FAO, 2004) export trade value. In the lowlands, sheep and goats are important means of livelihoods for pastoral communities. Extensive system of management with no or low external input and low output predominates in the country (Gizaw et al., 2010). Despite the huge population, optimal utilization of small ruminants in Ethiopia is constrained by disease, poor feeding, poor management and low genetic endowment (Ademosoum, 1992). Productivity and viability of sheep and goat farms depend largely on reproductive performance which in turn is regulated by genetic and environmental factors (Mellado et al., 2006).
Reproductive failure has a negative impact on livestock production, animal health and welfare and ultimately rural economies. There are several potential underlying causes of reproductive failure broadly categorized into infectious and non-infectious causes (Entrican, 2009). In ruminants, Toxoplasma gondii is among the major infectious causes of abortion which is also zoonotic pathogen (Ortega-Mora et al., 2007, Smith and Sherman, 2009). Non-infectious causes such as chemicals, plants, physical agents are also associated with reproductive failures (Hassig, 2007).
T. gondii infection may cause early embryonic death and resorption, fetal death and mummification (Dubey, 2009, Smith and Sherman, 2009), abortion, still births and neonatal death (Marquardt et al., 2000, Radostits et al., 2007, Dubey, 2009, Smith and Sherman, 2009, Solaiman, 2010). Severity of infection is associated with the stage of pregnancy at which the ewe becomes infected; the earlier the gestation period, the more severe the consequence (Dubey, 2009). These reproductive problems result in the loss of offspring and increased lambing/kidding interval, increased culling, reduced milk production and reduced value of breeding stock, hence leading to major economic losses (Marquardt et al., 2000, Ortega-Mora et al., 2007). Moreover, small ruminant abortion involves considerable public health risk (Ortega-Mora et al., 2007).
In Ethiopia, the factors affecting small ruminant reproductive efficiency and flock productivity are inadequately investigated (Mukasa-Mugerwa and Lahlou-Kassi, 1995) and the association of infectious causes with reproductive failures is largely unknown. However, the few studies undertaken in Ethiopia indicated significant association between Brucella seropositivity and abortion in cattle and goats (Megersa et al., 2011), in goats (Ashagrie et al., 2011) and in sheep (Yosef and Nardos, 2010). Vaccination program for brucellosis does not exist in Ethiopia in any of the animal species. In order to protect and sustain small ruminant industry, boost productivity and design appropriate control programs it is critical to have adequate knowledge about reproductive failures. Therefore, the aims of the present study were to estimate frequency of occurrence of flock level reproductive failures and assess associated potential risk factors including T. gondii infection in three districts of East and West Shoa Zones, Central Ethiopia.
Section snippets
Study areas and population
The study was conducted at Ambo, Ada’a-Liben and Fentale districts of Oromia Regional State, Central Ethiopia. Ambo district (longitude 37° 32′–38° 3′ E and latitude 8° 47′–9° 20′ N) is found in Western Shoa Zone while Ada’a-Liben (longitude 38° 58′ E–39° 22′ E and latitude 08° 22′ N–8° 56′ N) and Fentale (longitude 39.93° E–39° 56′0″ E and 8.975° N–8.58′30″ N latitude) districts are found in East Shoa Zone of Oromia Regional State. The altitude in Ambo and Ada’a-Liben is highland [>2300 m above
Seroprevalence of toxoplasmosis and its association with abortion
An overall 59.7% flock level seroprevalence of toxoplasmosis was found. Flock seroprevalence of toxoplasmosis was significantly different between study districts (P < 0.001) and species of animals (P = 0.001). The highest flock level seroprevalence was recorded from Ada’a-Liben district (80.6%, 95% CI: 71.32, 89.79). Seroprevalence was high in sheep flocks (66.7%, 95% CI: 60.47, 72.86) than goat flocks [Fig. 1].
An overall animal level seroprevalence was 31.8% (95% CI: 29.31, 34.25) and it was
Seroprevalence of toxoplasmosis and its association with abortion
An attempt was made to correlate flock history of reproductive failures (history of abortion, still birth, neonatal losses and number of abortions) with T. gondii seropositivity, since toxoplasmosis is an important cause of abortion in sheep and goats in different countries (Dubey and Beattie, 1988, Radostits et al., 2007, Masala et al., 2007, Smith and Sherman, 2009). According to the present study, significant association between T. gondii seropositivity and animal level abortion was observed
Acknowledgements
The financial support of Oromia regional state Rural Capacity Building, Addis Ababa University, VLIR-UOS Project No. “ZEIN 2010 PR 372” “promotion of the PhD program in veterinary public health at the Faculty of Veterinary Medicine”, Belgium, the Italian National Reference Centre for Toxoplasmosis at the Istituto Zooprofilattico Sperimentale della Sicilia A. Mirri, Italy and partial financial support to Maria Vitale Grant No. RF 2007/RC 2009 from Italian Ministry of Health are highly
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