Seroprevalence of Neospora caninum in cattle in Sudan

Aim: This cross-sectional survey was conducted to detect anti- N. caninum antibodies in bovine dams' sera samples in nine States of the Sudan. Materials and Methods: Two hundred and seventy six bovine dams' sera samples collected from nine States in the Sudan were screened for anti-Neospora caninum antibodies using a commercial competitive ELISA (cELISA) kits. Results: The results showed an overall prevalence rate of 15.9% (range 6.7% - 70%) of Neospora caninum antibodies. The prevalence rates were high in White Nile (70%) and North Kordofan (30%), moderate in the Northern (15.6%), Red Sea (13.3%) States and was low in the South Kordofan (9.4%) and River Nile (6.7%). States with high values of percentage inhibition (PI) detected in White Nile State compared to other States. No antibodies were detected in El Gadarif, Kassala and South Darfur States. The prevalence was observed to be high in crossbred dams (70%) with statistically significant difference (P<0.05) compared to local ecotype (9.3%). However, no correlation was observed between infection rates in two age groups. Conclusion: Neosporosis is prevalent in cattle in most States of Sudan. Absence of evidence of infection in three of the States investigated may reflect the small number of herds and sera tested.


Introduction
Clinical manifestations of Neosporosis are seen in dogs and cattle.The main clinical manifestation in Neosporosis is caused by the intracellular cattle infected with N. caninum is abortion.The protozoan parasite Neospora caninum and is known as diagnosis of Neosporosis in live animals can be one of the major causes of infectious abortion, achieved by detection of anti-N.caninum antibodies stillbirth and reproductive failure in cattle worldwide using different serological tests, such as the indirect [1].Neospora caninum was initially reported by fluorescence antibody test (IFAT), the Neospora Bjerkas, Mohn and presthus in Norway (1984) [2] as agglutination test (NAT), enzyme-linked immunosorbent causing encephalitis in dogs.The parasite was later assay (ELISA) and Western blotting.ELISA is an isolated in tissue culture [3].Domestic canids are the approved serological test [6] that has been used in natural definitive host for N. caninum [4].Infected epidemiological studies to estimate the prevalence of dogs excrete unsporulated oocysts in their faeces in the N. caninum infections, examine the relationship environment.Under favorable environmental between exposure to N. caninum and abortion, milk conditions the oocysts sporulate and infection of the yields and culling in cattle [7].In Sudan, the first intermediate hosts (cattle, sheep, goats, deer, horses record of N. caninum infection in cattle has recently etc) occurs through ingestion of the sporulated cysts.been reported by Ibrahim et al. [8] in Gezira and Vertical transmission has also been documented and is Khartoum States.highly responsible for the positive animals tested [5].
Owing to the meagre data available on  States of Sudan.Absence of evidence of infection in Screening bovine sera samples collected from three of the States investigated may reflect the small nine States in Sudan for anti-N.caninum antibodies number of herds and sera tested.This is supported by showed prevalence rate that ranged from 6.7% in the fact that not all herds tested in Khartoum and River Nile to 70% in White Nile with no antibodies Gezira States of Sudan were positive for Neospora detected in El Gadarif, Kassala and South Darfur caninum antibodies.Therefore, further large scale States.The difference in prevalence rates between epizootiological investigations on Neospora caninum States may be attributed to environmental differences infection including other farm animals at the country between geographical areas and topographical reasons level are necessary to fully evaluate the epidemiology that affect oocysts development and survival [16] and and economic impact of this parasite in Sudan.to the limited numbers of herds tested.However, the high prevalence rate detected in White Nile State Authors' contribution (70%) is hard to explain but it is worth mentioning that M. O. Hussien, A. M. Elfahal and K. A. Enan carried all samples (30) in this state were collected from out the ELISA assays and drafted the manuscript.M. crossbred dams from one modern dairy farm unlike all S. Mohammed, A. M. Elhassan and K. M. Taha done other samples which were collected from local the samples and data collection.A. M. El Hussein ecotype dams.Many authors [17,18] have shown that contributed to the conception and design of the study the presence of farm dogs (natural definitive host for and revised the manuscript.All authors read and N. caninum) is a risk factor for N. caninum infection in approved the final manuscript.cattle.Infectious materials, like aborted fetuses, dead calves and fetal membranes could be major sources of Acknowledgements infection to dogs.Thus the high seroprevalence of The authors wish to thank Professor Ali Yousif Neosporosis might be related to the presence of many Osman for his valuable comments, suggestions and stray and domestic dogs on the dairy farm premises critical reading of the manuscript.We are grateful to noticed at the time of the study visit in White Nile Dr. Salaheddin O. Hassan, Dr. Saliem M. Abdel State.Moreover, management systems are also noted Rahman, Dr. Mohammed D. Idris, Dr. Ahmed A. to affect breed seroprevalence more than breed related Saeed and Dr. Mohammed M. Gumaa for providing susceptibility to infection [1].
the samples.This research was funded by Central The prevalence as observed here in crossbred laboratory, Ministry of Science and Technology, females (70%) was significantly higher (P<0.05)than Khartoum Sudan. in local ecotype (9.3%).This is in disagreement with Ibrahim et al. [8] who reported that no significant Competing interests difference between crossbred and local ecotype Authors declare that they have no competing interests.bovine dams was observed in Khartoum and Gezira States.This may be attributed to the fact that crossbred References dams were the predominant type studied by Ibrahim et 1.

To cite this article: Hussien
Study area:The survey was conducted during the detected by the addition of enzyme substrate and period from February to December 2011 in the quantified by subsequent colour product development.Northern,Western and Eastern Sudan and White NileWeak colour development due to inhibition of the aimed to cover most of the country.Selection of these monoclonal antibody binding to the antigen coated in locations was based on them being the main potential the plates indicates the presence of N. caninum areas for livestock rearing.Selection of farms was antibodies in sample sera.The cutoff value of antibody made randomly and the formal mechanism used was percentage inhibition (PI) is > 30 i.e. all samples which lottery.have antibody PI > 30 are considered positive.

Sample collection: Five ml of blood sample from Results each
of two hundred and seventy six dams of two age groups (3-4 years and 4years and above) were Anti-N.caninumantibodies were detected in six collected from nine States in Sudan, viz.El Gadarif, (67%) out of nine States with varying prevalences.The Kassala, North Kordofan, Red Sea, River Nile, South prevalence rates of antibodies ranged from 6.7% in Darfur, South Kordofan, the Northern and White Nile River Nile State to 70% in White Nile State.The States during February-December, 2011.All animals prevalence rates were high in White Nile (70%) and examined in this study were lactating cows and Northern Kordofan (30%), moderate in the Northern belonged to small-scale farms.The presence of farm (15.6%),RedSea (13.3%) and low in South Darfur dogs was observed in majority of selected farms.Sera (9.4%) and River Nile (6.7%) States, with an overall were separated by centrifugation at 1500 rpm / min.prevalence of 15.9% (44/276) with high values of for 10 minutes and kept at -20OC until tested.The percentage inhibition (PI) detected in White Nile State investigation was carried out in compliance with the compared to other States (data not shown).No anti-N.animalwelfare code in Sudan.caninumantibodies were detected in El Gadarif, Kassala and South Darfur States (Table-1).
ELISA technique: Commercial competitive ELISA

Table - 1
. The prevalence rate of anti-N.caninum antibodies in bovine dams in nine States in the Sudan during the period February-December, 2011

Table - 2
. Influence of breed and age groups on seroprevalence of Neospora caninum in bovine dams in nine States in the Sudan during the period February-December, 2011.Neosporosis has been reported in many detected in White Nile State compared to other States countries [9-15] with different prevalence rates since may indicate the high intensity of infection in this the disease was recognized in 1988 [3].The state.prevalence of Neosporosis reported in the current DiscussionThe high values of percentage inhibition (PI)