Animal toxoplasmosis is of public health and economic importance worldwide. The present study designed to investigate the disease in cattle, sheep and goats in River Nile State during January to march 2016. A total of 191 serum samples were checked for antibody against T. gondii using Latex Agglutination Test. The overall prevalence rate was 16.8%. Statistically significant variation (p = 0.017) between the two investigated areas (Atbara and Eldamar) was observed. Goats revealed significantly (p = 0.000) higher prevalence rate (27.9%) than by sheep (26.5%) and cattle (6.2%).

The prevalence rate was also affected significantly by sex (p = 0.026) and age groups (p = 0.28). Breed variation has no statistically significant (p = 0.382) effect in the seroprevalence rate of toxoplasmosis in this study. Without any statistically significant differences (p > 0.05), the level of antibody titration was higher in goats than in sheep and cattle, in females than in males, in aged animals than in the young ones. In the present study, 12.5% of the new borne animals (1-6 months) were seropositive for T. gondii infection. Up to our knowledge, this paper may be the first report on seroprevalence of animal toxoplasmosis in the River Nile State. Extension and education for consumption of proper cooked meat and milk will be of public health value in the State.

Toxoplasma gondiiis one of the most important causes of protozoal parasitic infectious abortion in livestock worldwide (Malik., et al. 1990; Huong., et al. 1998). The parasite is widely prevalent in humans and animals on all continents (Dubey 2004; Innes 2011; Ibrahim and Abakar 2015). Most of human infection were during consumption of raw or under-cooked meat or other edible parts of meat producing animals (Slifko., et al. 2000; Tenter., et al. 2000; Ibrahim., et al. 2015).

The worldwide average value of seroprevalence of T. gondii infection in cattle was 9% (Dubey, 2004; Nematollahi and Moghaddam 2008). In Iran, Hashemi-Fesharki (1996) fail to detect antibodies against T. gondii in cow sera diluted 1:8 and 1:64 using LAT and IHAT respectively. However, Ciamak-Ghazaoi, (2005) and Nematollahi and Moghaddam (2008) reported 9% and 15.9% seroprevalence of cattle toxoplasmosis using ELISA and IFAT respectively.

The first available data on cattle toxoplasmosis in Western and Central Sudan was reported by Zein Eldin., et al. (1985). Thereafter, the parasite was investigated in cattle from central Sudan using different serological techniques (Khalil and Elrayah 2011; Elfahal., et al. 2013; Ibrahim., et al. 2014).

There are numerous reports on seroprevalence of toxoplasmosis in sheep worldwide, ranging from 0% to 100% (Fayer 1981; Tenter., et al. 2000; Ortega-Mora., et al. 2007). According to Fayer (1981), the world average of seroprevalence of sheep and goats was 31%. Toxoplasmosis occurs in all breeds (Ragozo., et al. 2009), sex (Bonyadian., et al. 2007) and age (Bahrieni., et al. 2008; Anamaria., et al. 2008) groups of ewes and their foetuses. In Egypt, serological surveys indicated that the incidence of infection average was 9.4 and 6.9% in sheep and goats respectively (Hassan., et al. 2000).

In Sudan, the earliest studies on sheep and goats were carried out by Elbedawi., et al. (1984) and Zein Eldin., et al. (1985). The most recent serological studies were that of Abdel Hafez (2013) and Ibrahim., et al. (2014).

Most of the available data on animal toxoplasmosis in the Sudan was collected from the Central Sudan. The present study was planned to address the prevalence of animal toxoplasmosis in River Nile State using Latex agglutination test.

Study area
The study was conducted in the River Nile State which located in Northern Khartoum State and between altitude 16°E-22°E and longitude 32°N - 35°N. The area of the state is 124, 000km2. The climate of the state is semi-desert. The average of temperature ranges from 47°c in the summer to 8°c in the winter. The numbers of animals in the River Nile State are modest compared to other states of the country. It estimated of 1,034,655 sheep, 1,211,095 Goat, 100,701 cattle, and 114,103 camel. The study areas included Atbara and Elda mar.

Animals: The study population encompassed 191 animals of different sex and age including cattle (96 heads), sheep (34 heads) and goats (61 heads).

Samples: Blood samples were obtained from the jugular vein of 191 animals during January-March 2016. Serum was removed from each clotted blood sample and stored at -20⁰C until tested.

Latex Agglutination Test (LAT)
The Toxo-Latex diagnostic kit (Spinreact, S.A./S.A.U, Spain) was purchased from Shifak Company, Khartoum, Sudan (Appendix 1). Initially, all sera were examined qualitatively based on the LAT manufacturer’s instructions. Visible clumps indicate positive agglutination. The positive samples were subjected to semi-quantitative test to obtain the level of antibody titration usingserial double dilutions of 1:4 up to 1:256.

Data analysis: Data was analyzed using the statistical package for social sciences (SPSS) version 20. A p-value less than 0.05 were considered statistically significant.

Seroprevalence rates of T. Gondii infection in River Nile State
The overall sero-prevalence rate in the examined animals was 16.8% (table 1). Eldamar area showed higher prevalence rate than Atbara with statistically significant variation (p = 0.017). The prevalence rates were significantly varies (p = 0.000) between the three different animal species (table 2). As shown in table (4 & 5), significant differences were observed in the seroprevalence of T. gondii infection between the different sexes (p = 0.026) and the different age groups (p = 0.28). However, there was no any statistically significant variation (p = 0.382) in the prevalence rate between the local and the foreign breeds (table 3).

Titration of antibodies against T. gondii in the positive reactions
The distribution of specific antibody titers to T. gondii positive reaction was not significantly (p > 0.05) affected by the different areas, animal species, breeds, sexes or age groups (table 1, 2, 3, 4, 5). However, the positive sera of goats and sheep recorded the highest level of antibody titration (1:128) while the highest titration in cattle was 1:16 (table 2). Female animals showed higher titration than males (table 4) and the titration increased with the age (table 5).

The present study pointed out that, the seroprevalence rate of T. gondii infection in goats (27.9%), sheep (26.5%) and cattle (6.2%) were higher than the world average (Fayer 1981; Dubey, 2004). These results were lower than the results obtained from Central and Western Sudan (Zein Eldin., et al. 1985; Khalil and Elrayah 2011; Abdel Hafez 2013; Ibrahim., et al. 2014), and higher than the reports from Egypt (Hassan., et al. 2000), South Africa (Abusamra., et al. 2007) and Iran (Bahrieni., et al. 2008). The higher infection rate in goat than the in sheep is in contrast with the findings in many Seroprevalence studies in Iran (Bahrieni., et al. 2008) and Sudan (Ibrahim., et al. 2014; Zein Eldin., et al. 1985). Lower infection in cattle compared to those in goats and sheep may be attributed to the differences in susceptibility to T. gondii and to the feeding habits of these animals (Bahrieni., et al. 2008; Dubey and Hamir 2002). In agreement with many authors (Wiss and Kim 2007; Taylor., et al. 2007; Ortega-Mora., et al. 2007; Innes, 2011), the present work also confirmed that, goats and sheep were more susceptible to T. gondii infection than cattle when they recorded the highest seroprevalence and antibody titration (1:128). Hashemi-Fesharki, (1996) found no positive reaction against T. gondii in sera of 2000 cows. Therefore, he and Dubey (1986) supported the hypothesis that cattle are not favored hosts for T. Gondii. However, at least one outbreak of human toxoplasmosis whose source was raw beef has been documented (Smith 1993).

Toxoplasmosis occurs in all breeds (Abdel Hafez 2013; Ragozo., et al. 2009), sex (Gebremedhin., et al. 2013; Nematollahi and Moghaddam 2008; Bonyadian., et al. 2007) and age groups (Bahrieni., et al. 2008; Anamaria., et al. 2008). In the present study, the tested factors like area, animal species, sex and the age were found to have significant effect (p < 0.05) on the seroprevalence of T. gondii infection in the River Nile state.

In this study, 12.5% of the seropositive cases are new borne animals (1-6 month). This may increase the possibility of the occurrence of congenital transmission in the tested animals. In the Sudan people prefer sheep mutton; however, the majority of them consume beef, thus increasing the importance of cattle as a source of toxoplasmosis infection in the country. Under-cooked meat of sheep, goats and cattle are widely consumed in the Sudan (Elhassan., et al. 1991).

Up to our knowledge, this is the first evidence of animal toxoplasmosis in the River Nile State. Extension and education for consumption of proper cooked meat and milk in the area is recommended.