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???metadata.dc.contributor.*???: Dr. Yacob Hailu
Berhanu, Tilahun
Keywords: Ruminants;Seroprevalence;Toxoplasma gondii
Issue Date: Oct-2015
Abstract: Toxoplasmosis is a zoonotic disease caused by Toxoplasma gondii capable of infecting all warm-blooded animals including man. It is unevenly spread across the world at varied prevalences in different host species. In Ethiopia, as there was no nation-wide survey, the status of T. gondii infection in several areas remains unknown. Therefore, a cross-sectional sero-epidemiological study of T. gondii infection was conducted from July 2011 to September 2013 in three selected districts of East Hararghe Zone of Oromia Region, Ethiopia, in order to determine the seroprevalence and identify the risk factors of T. gondii infection in animals and humans as well as to isolate T. gondii from infected animal tissues. A structured questionnaire was administered to one hundred randomly selected individuals whose animals were included in the study to collect information on variables such as sex, age, herd/flock size, cats contact, presence of feral cats, and source of water, type of housing and geographical location in an attempt to identify the risk factors attributing to T. gondii infection in animals. Animals sera (n = 1360) were tested for the presence of anti-T. gondii antibodies by ELISA using the ID vet Screen Toxoplasmosis multi-species indirect kit (IDVET, Montpellier, France). Sera were collected from humans and a questionnaire was administered to collect data on potential risk factors. Toxoscreen DA and Toxo-ISAGA diagnostic kits were employed for the detection of Anti-T. gondii IgG and IgM antibodies in human sera, respectively. All factors attributing to T. gondii infection in human and animals were analyzed using chi-square test and logistic regression analysis. Accordingly, serologic evidence of T. gondii infection was detected in 32 (84.2%) out of 38 farm areas. The seroprevalence of T. gondii infection in sheep, goats, cattle and camels was 33.7%, 27.6%, 10.7% and 14.4% at animal level and 60.8%, 55.8%, 23.2%, and 53.2% at flock/herd level, respectively. On multivariable logistic regression analysis the risk factors significantly associated with T. gondii seropositivity were female gender [odds ratio (OR) 2.63, 95% confidence interval (CI) 1.18–5.88, P = 0.019], use of pond (OR: 4.25, 95% CI: 2.15–8.38, P < 0.001) and pipe water in sheep (OR: 9.57, 95% CI: 5.00–18.33, P < 0.001); adult age (OR: 3.45, 95% CI: 1.34–8.90, P = 0.010), use of pond (OR: 6.03, 95% CI: 2.42–15.05, P < 0.001) and pipe water (OR: 11.61, 95% CI: 4.35–30.95, P < 0.001) in goats; use of pond (OR: 5.60, 95% CI: 2.12–14.78, P < 0.001) and pipe water (OR: 10.68, 95% CI: 2.23–51.22, P = 0.003) in cattle; adult age (OR: 2.49, 95% CI: 1.14–5.42, P = 0.22) in camels. In human, the T. gondii IgG (n = 354) and IgM (n = 167) seroprevalences were 65.8% (95% CI: 60.62–70.75) and 8.9% (95% CI: 5.11–14.38) respectively. Gender difference in IgG seroprevalence was not statistically significant (P > 0.05), but 69.5% of adults exhibited an IgG seroresponse to T. gondii. Pregnant women showed 76.4% and 9.3% anti-T. gondii IgG and IgM antibodies, respectively. The risk factors identified significantly associated with T. gondii seropositivity in human on multivariable logistic regression analysis were district (OR = 2.24, 95% CI: 1.25–4.01, P = 0.007), pipe water source (OR = 6.70, 95% CI: 2.70–16.64, P < 0.001), adult age (OR = 4.32, 95% CI: 1.91–9.75, P < 0.001), and keeping cats in the home (OR = 2.01, 95% CI: 1.11–3.65, P = 0.021). Viable T. gondii tissue cysts were isolated by bioassay in mice from the hearts of 23 (67.6%) sheep and goats. In conclusion, the detection of T. gondii infection among domestic ruminants indicates the potential risk presented to humans from food animals. The IgM seropositivity detected among pregnant women warrants the potential risk of congenital transmission. The principal source for acquisition of T. gondii infection both in animals and humans was the water source. Thus, inlight of this the impact of T. gondii infection on the health, production and reproduction of domestic ruminants, the extent of congenital transmission and water contamination requires further future investigation.
Description: A Dissertation submitted to the College of Veterinary Medicine and Agriculture of Addis Ababa University in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Veterinary Parasitology
Appears in Collections:Thesis - Tropical Veternery Medicine

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