Sero-Prevalence of Anti-Brucella Antibodies in Goats in El- Gedarif State, Eastern Sudan
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ARC Journal of Animal and Veterinary Sciences Volume 4, Issue 1, 2018, PP 1-8 ISSN No. (Online) 2455-2518 DOI: http://dx.doi.org/10.20431/2455-2518.0401001 www.arcjournals.org Sero-Prevalence of Anti-Brucella Antibodies in Goats in El- Gedarif State, Eastern Sudan Khuzaima Babiker Adam1 , Hatim Hamad Ibrahaem2*, Yassir Adam Shuaib3, Saad El-Tiab Mohamed-Noor3, Ali Abdelgani Elgadal2, Mohamed Taha Shigidi4, Abdel Hafeez Hassan Nimir4 1 Ministry of Animal Resources, El-Gadarif, El-Gadarif state, the Sudan 2 Veterinary Research Institute, Soba, P.O. Box 8067, Khartoum, Sudan 3 College of Veterinary Medicine, Sudan University of Science and Technology, P.O. Box 204 (Hilat Kuku), Khartoum North, the Sudan 4Faculty of Veterinary Medicine, University of Khartoum, P.O. Box 13314 (Shambat), Khartoum North, the Sudan *Corresponding Author: Hatim Hamad Ibrahaem, Veterinary Research Institute, Soba, P.O. Box 8067, Khartoum, Sudan. Email: [email protected] Abstract: This cross-sectional study was carried out between January and April 2014 with the aim of determining the seroprevalence of anti-brucella antibodies in goats in El-Gedarif state, the Sudan. A total number of 426 serum and 15 milk samples were collected from the study animals from eight different localities. These samples were examined using rose Bengal plate test (RBPT), serum agglutination test (SAT), competitive enzyme-linked immunosorbent assay (cELISA), and milk ring test. An overall seroprevalence of 10.8% (n=26, 95% CI between 7.85 and 13.75) was reported. Of the RBPT-positive samples, SAT confirmed the positivity of 13.0% (n=6). Furthermore, 6.5% (n=6) of the samples tested by cELISA showed positive results. There were no significant statistical differences in the reported seroprevalences among the categories of the investigated risk factors. Location (χ2=31.62, df=7, p-value=0.001) was associated with RBPT-positive status for brucella in the univariate analysis. Moreover, Basunda locality and animals with no history of abortion had an increased odd of being RBPT positive. It can be concluded that location and history of abortion were risk factors associated with brucella positive status. Further studies investigating brucellosis across the whole state using molecular methods should be carried out to better understand the epidemiology of brucellosis in goats. Keywords: Sero-prevalence, RBPT, brucellosis, goats, Sudan 1. INTRODUCTION between animals typically occurs through contact with infected animals or materials with Brucellosis is a contagious disease of animals skin abrasions (Plummet et al., 1998; Lapaque and it is transmissible to man (Radostits et al., et al., 2005). The ability of brucella species to 2007; Angara and Shuaib, 2015). It is caused by replicate and persist in host cells is directly the members of the genus Brucella which are associated with their capacity to cause persistent small, non-motile, aerobic, facultative disease and to circumvent innate and adaptive intracellular, Gramnegative coccobacilli. immunity (Greenfield et al., 2002; Fichi, 2003; Brucella melitensis, B. abortus, B. suis, B. Young, 2005; Radostits et al., 2007). From neotomae, B. ovis, and B. canis are important public health point of view, brucellosis is etiological agents of brucellosis in domestic considered to be an occupational disease that animals. In sheep and goats, B. melitensis and B. mainly affects slaughterhouse workers, ovis are the most common etiological agents of butchers, and veterinarians (Plummet et al., brucellosis (Geering et al., 1995; Muma et al., 1998; Muma et al., 2006; Radostits et al., 2007). 2006; Musa et al., 2008). Though brucellosis has been eradicated in many developed There are many factors that enhance the countries, it remains an uncontrolled problem prevalence of brucellosis in animals (Salih et al., and endemic in some parts of the world like 2016; Wegdan et al., 2016). Prevalence of many African and Asian countries (Refai, 2002; brucellosis can vary according to climatic Muma et al., 2006). Transmission of brucellosis conditions, geography, species, sex, and age ARC Journal of Animal and Veterinary Sciences Page | 1 Sero-Prevalence of Anti-Brucella Antibodies in Goats in El-Gedarif State, Eastern Sudan (Muma et al., 2006; Abdallah et al., 2015; Salih 2.3. Sample Size et al., 2016; Wegdan et al., 2016). Almost all The standard formula of Thrusfield (2007) was domestic animal species can be affected with used to calculate the sample size (n) for brucellosis except cats which are resistant to determining the prevalence of anti-brucella brucella infection (Muma et al., 2006; Radostits antibodies in goats. Considering all parameters et al., 2007). Considering the damage done by of the formula, n was determined to be 426 the infection in animals in terms of decreased animals. milk production, abortions, weak off springs, weight loss, infertility and lameness, brucellosis 2.4. Collection of Samples is one of the most serious diseases of livestock. Blood samples were taken aseptically from the It is also a major impediment for trade in jugular vein using vacutainer tubes which were animals and animal products. Death may occur put in rack and left in a refrigerator at 4⁰C as a result of acute metritis followed by retained overnight. After clot formation, the samples fetal membranes (Radostits et al., 2007). were transported to the Veterinary Research Brucellosis in goats in Sudan is not very well Laboratory, El-Gedarif, the Sudan, where sera studied; only few surveys have been conducted were separated and tested for anti-brucella (Ahmed, 2004; Rayas, 2004; Musa, 2006). This antibodies on the same day after collection. The study was conducted to determine the rest of the sample was stored at -20⁰C for seroprevalence of brucellosis in goats in El- further use. Gedarif state. Fifteen milk samples, 10 ml each, were 2. MATERIALS AND METHODS collected after cleaning the teats with water and 2.1. Study Area alcohol into universal bottles. The samples were kept in a refrigerator at 4⁰C and were El-Gedarif state is located in the Eastern part of tested within 24 hours of collection. the Sudan; longitudes 33⁰30 and 36⁰30’ East and latitudes 12⁰40’ and 15⁰46’ North. It has an 3. LABORATORY PROCEDURES area of 75,263 km². The state falls within the 3.1. Rose Bengal Plate Test Sudano-Sahelian climate zone of Africa. It has The Rose Bengal platetest (RBPT) was carried an international border with Ethiopia from the out as described by OIE (2009). The procedure East and national borders with Kassala and of the test was as follow: i) serum samples and Khartoum states from the North, with El-Gezira antigen were brought to room temperature first, state from the West and with Sinnar state from ii) then, 25 μl of each serum sample was place the South. The total population of goats in El- on a porcelain plate, iii) an equal volume of Gedarif state is about one million head including antigen was placed near each serum spot, iv) indigenous ecotypes and exotic breeds as well as serum and antigen were then mixed thoroughly their crosses (MARF, 2009). Different animal (using a clean wood rod for each sample) to production systems predominate in El-Gedarif produce a circular or oval zone approximately 2 state; such as mixed crop-livestock system, cm in diameter, v) the mixture was agitated nomadic, and semi-nomadic systems in the gently for 4 minutes at ambient temperature on a region (ILRI, 2009). rocker, and finally, vi) agglutination was immediately read for after that. 2.2. Study Design and Sampling Strategy The interpretation of the result was done This cross-sectional study was conducted for 4 according to the degree of agglutination, which months, from January to April 2014, using a was recorded as 0, +, ++ and +++. A score of 0 multistage sampling strategy (Thrusfield, 2007). indicated the absence of agglutination; a score Eight localities (administrative units) of the of + indicated barely visible agglutination; ++ localities of El-Gedarif state were randomly or indicated fine agglutination and +++ indicated conveniently selected. These were Al-Fao, El- coarse clumping. Those samples with no agglutination (0) were recorded as negative Gadarif, Al-Hawata, Al-Showak, Basunda, while other were recorded as positive. Dokah, Al-Guraisha, and Kassab. Within each of the selected localities, peasant association or 3.2. Serum Agglutination Test (SAT) villages, goat flocks, and individual animals The serum agglutination test (SAT) was carried were randomly and/or conveniently sampled out as described by OIE (2009). To overcome (Thrusfield, 2007). the prozone phenomenon, if any to occur, 7 ARC Journal of Animal and Veterinary Sciences Page | 2 Sero-Prevalence of Anti-Brucella Antibodies in Goats in El-Gedarif State, Eastern Sudan tubes were used for each serum sample. An sixty columns (wells). A volume of 100 μl of the amount of 0.8 ml of phenol-saline was placed in prepared conjugate solution was then dispensed the first tube and 0.5 ml in each succeeding one. in all wells. It was then shaken for 2 minutes in Then 0.2 ml of the serum sample was order to mix the serum with the conjugate transferred to the first tube and mixed solution. The plate was then covered with a lid thoroughly with the phenol-saline until it the and incubated at room temperature for 3 mixture became homogenous. Then an amount minutes. The content of the plate was after that of 0.5 ml of the mixture was carried over to the discarded and rinsed 5 times with washing second tube from which, after mixing, 0.5 ml solutions and then dried. Thereafter, 100 μL of was transferred to the third tube, and so on. This the substrate chromogen solution was added to process was continued until the last tube, from all wells.