Abstract
Brucellosis is a highly contagious zoonotic disease caused by bacteria of the genus Brucella. Camel brucellosis poses significant public health concerns and hampers socio-economic development in developing countries, particularly in pastoral regions. Despite its endemic status in many areas, limited attention has been given to the disease in camels. This study aimed to determine the seroprevalence and associated risk factors of camel brucellosis in the Dagahbur and Dagahmadow districts of the Jarar zone, Somali Regional State, Ethiopia. A cross-sectional study was conducted from July 2024 to May 2025. A total of 384 camels from six kebeles across the selected districts were included using a multi-stage sampling technique. Serum samples were tested using the Rose Bengal Plate Test (RBPT) and confirmed with Competitive ELISA (cELISA). Logistic regression analysis was performed to identify associated risk factors. The overall seroprevalence was 27.86% by RBPT and 3.9% by cELISA. Camels with a history of abortion were over twice as likely to test positive (AOR = 2.23, p = 0.002), and those with retained fetal membranes had a sixfold increased risk (AOR = 6.27, p = 0.001). Demographic factors such as sex, age, and herd size showed no significant association. Camel brucellosis remains prevalent in the study area, with reproductive disorders identified as key risk factors. Coordinated efforts among stakeholders are needed to implement preventive and control measures, alongside increasing public awareness to curb the spread and reduce disease prevalence.
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Published in
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World Journal of Health Services Research (Volume 1, Issue 1)
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DOI
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10.11648/j.wjhsr.20260101.13
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Page(s)
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25-34 |
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Creative Commons
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This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
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Copyright
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Copyright © The Author(s), 2026. Published by Science Publishing Group
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Keywords
Seroprevalence, Brucellosis, Camel, Public Health, ELISA, RBPT, Risk Factors
1. Introduction
The world camel population is steadily expanding and is expected to reach 60 million in the next 25 years
| [1] | Faye, B. How many large camelids in the world? A synthetic analysis of the world camel demographic changes. Pastoralism: Research, Policy and Practice. 2020, 10(1), 25.
https://doi.org/10.1186/s13570-020-00176-z |
[1]
. Africa is home to more than 80% of the world's dromedary population (16.5 million), with East Africa accounting for 63%. Chad, Somalia, and Sudan have the highest camel populations in Africa, hosting approximately 9.4, 7.4, and 4.9 million camels, respectively
| [2] | Masebo, N., Bitew, M., Ayelet, G. Camel population dynamics and health in East Africa. Journal of African Livestock Research. 2023, 12(1), 45-58. |
[2]
.
Brucellosis is a highly contagious, infectious, and communicable disease caused by Brucella bacteria, recognized as one of the world's most common zoonoses by global health organizations including the Food and Agriculture Organization (FAO), World Health Organization (WHO), and the World Organisation for Animal Health (OIE)
| [3] | Alhussain, H., Al-Ali, A., Al-Mohammed, H. Brucellosis: A re-emerging zoonosis with global concern. Journal of Infection and Public Health. 2022, 15(6), 654-662. |
[3]
. According to the OIE, it is the world's second most important zoonotic disease after rabies, accounting for over 500,000 human cases reported each year
| [4] | Ekere, S. O., Njoga, E. O., Onunkwo, J. I., Njoga, U. J. Serosurveillance of Brucella antibody in food animals and role of slaughterhouse workers in spread of Brucella infection in Southeast Nigeria. Veterinary World. 2018, 11(8), 1171-1178.
https://doi.org/10.14202/vetworld.2018.1171-1178 |
[4]
. The disease is prevalent in camel-rearing regions worldwide, including the Middle East, Africa, and Latin America, with exceptions such as Australia
| [5] | Potter, B. Brucellosis in Australia. Australian Veterinary Journal. 2013, 91(3), 98-102. |
| [6] | Wernery, U. Camelid brucellosis: a review. Revue Scientifique et Technique (International Office of Epizootics). 2014, 33(3), 839-857. https://doi.org/10.20506/rst.33.3.2322 |
[5, 6]
.
In Africa, brucellosis is widespread, with persistent cases reported in humans and domestic animals in countries such as Tanzania, Nigeria, Uganda, Kenya, Zimbabwe, and Somalia
| [7] | Racloz V, Schelling E, Chitnis N, Roth F, Zinsstag J. Persistence of brucellosis in pastoral systems. Revue Scientifique et Technique (International Office of Epizootics). 2013; 32(1): 61–70. https://doi.org/10.20506/rst.32.1.2186 |
[7]
. In East Africa, the disease is endemic in most IGAD member states, causing substantial economic losses and health challenges
. Cross-species transmission is common, with Brucella bacteria affecting various domestic and wild animals, leading to significant reproductive losses in sexually mature animals
| [9] | Bekele, M. Brucellosis in livestock and its public health significance in Ethiopia: A review. Ethiopian Veterinary Journal. 2013, 17(2), 1-20. |
[9]
. Studies have identified B. abortus and B. melitensis as the primary strains isolated from infected camels, particularly from milk, aborted fetuses, and vaginal swabs
| [10] | Abou-Eisha, A. M. Brucellosis in camels and its relation to public health. Assiut Veterinary Medical Journal. 2000, 44(87), 54-64. https://doi.org/10.21608/avmj.2000.182064 |
| [11] | Angesom, H., Molla, B., Ashenafi, H. Sero-epidemiology of camel brucellosis in the Afar region of Northeast Ethiopia. Journal of Veterinary Medicine and Animal Health. 2013; 5(9): 269–275. https://doi.org/10.5897/JVMAH2013.0235 |
| [12] | Musa MT, Eisa MZ, El Sanousi EM, Abdel Wahab MB, Perrett L. Brucellosis in camels (Camelus dromedarius) in Darfur, Western Sudan. Journal of Comparative Pathology. 2008; 138:151–155. https://doi.org/10.1016/j.jcpa.2007.10.005 |
[10-12]
.
Brucellosis is among the most critical zoonotic diseases globally, largely due to a lack of public awareness and effective control measures, particularly in low-income countries
| [13] | Corbel, M. J. Brucellosis in Humans and Animals. Geneva: World Health Organization; 2006. |
[13]
. In Ethiopian pastoral settings, brucellosis is often endemic and difficult to control due to limited access to veterinary healthcare services and traditional livestock practices that contribute to the spread of the disease
| [14] | Minda, A., Gezahegn, M., Belay, N. Challenges in controlling brucellosis in Ethiopian pastoral areas. Journal of Veterinary Science and Technology. 2016, 7(3), 335-342. |
[14]
. The disease causes abortion, sterility, and reduces milk yield in animal health
| [15] | Megersa B, Biffa D, Abunna F, Regassa A, Godfroid J, Skjerve E. Seroprevalence of brucellosis and its contribution to abortion in cattle, camel, and goat kept under pastoral management in Borana, Ethiopia. Tropical Animal Health and Production. 2011; 43(3): 651–656.
https://doi.org/10.1007/s11250-010-9748-2 |
[15]
. Camel herders in pastoral areas are at high risk of contracting the disease because of close contact with camels and camel products for their livelihood
| [16] | Tilahun, B., Tolosa, T., Regassa, A. Knowledge, attitude, and practices of camel herders towards brucellosis in Ethiopia. Journal of Public Health and Epidemiology. 2013, 5(7), 298-305. |
[16]
.
Brucellosis affects humans by causing symptoms such as fever, sweating, and joint pain, which can lead to serious complications if left untreated
| [17] | Addis, M. Public health and economic importance of brucellosis: A review Public Policy and Administration Research. 2015, 14(3), 334-341. |
[17]
. Pregnant women infected with brucellosis are at risk of miscarriage, stillbirth, or premature birth
. Additionally, the disease can cause economic losses including the cost of treatment, fetal losses, infertility, reduced milk production, prolonged calving intervals, and losses due to the culling of animals
| [19] | McDermott J, Grace D, Zinsstag J. Economics of brucellosis impact and control in low-income countries. Revue Scientifique et Technique (International Office of Epizootics). 2013; 32(1): 249–261. https://doi.org/10.20506/rst.32.1.2197 |
[19]
.
In Ethiopia, diverse prevalence proportions of brucellosis among camels have been documented across different regions. Studies have reported prevalence of 2% in Dire Dawa
| [20] | Waktole H, Aden M, Ashenafi H. Seroepidemiology of camel brucellosis in and around Dire Dawa, Eastern Ethiopia. Veterinary Medicine International. 2022; 2022: 6624293.
https://doi.org/10.1155/2022/6624293 |
[20]
, 4.1% in Afar
| [21] | Gizaw F, Fentahun G, Mersha S, Bedada H. Seroprevalence and risk factors of brucellosis among camels belonging to selected districts of Afar, Ethiopia: Need for public awareness. American Journal of Microbiological Research. 2017; 5(5): 94–100. https://doi.org/10.12691/ajmr-5-5-1 |
[21]
, and 2.8% in the Somali region
| [22] | Teshome H, Molla B, Tibbo M. A seroprevalence study of camel brucellosis in three camel-rearing regions of Ethiopia. Tropical Animal Health and Production. 2003; 35:381–390. https://doi.org/10.1023/A:1025874310261 |
[22]
. A recent systematic review reported an aggregated prevalence proportion of 3% in camels at the national level in Ethiopia
. However, there is limited understanding of the extent of disease in camels in the Jarar zone, Somali Region, highlighting the need for this study.
This study is significant for improving disease control strategies, enhancing livestock welfare, and safeguarding the health of communities in the region. Educating the community about the importance of pasteurizing camel milk and adhering to proper hygienic practices is important given its impact on public health, animal health, and economic consequences, especially in pastoral Somali regions. There is a limited understanding of the extent of disease in camels and its herders that share the same ecological environment. The productivity of camel herds found in the Somali Regional State and Ethiopia in general is considered low.
Although the presence of bacterial diseases in livestock has been investigated in some parts of eastern Ethiopia
| [23] | Mekonnen, A. S., Yuya, H. M., Ahmed, A. S. Prevalence, Associated Risk Factors and Major Bacterial Pathogens Causing Bovine Mastitis on Selected Dairy Farms in and around Harar, Ethiopia. Vet Med Open J. 2023, 8(1), 38-46.
https://doi.org/10.17140/VMOJ-8-175 |
[23]
, the seroprevalence of Brucella species in camels, their associated risk factors, and their public health implications in the Jarar Zone have not been adequately explored. This study was therefore designed to address this critical knowledge gap.
1.1. General Objective
To assess the seroprevalence and associated risk factors of camel brucellosis in selected districts of Jarar zone, Somali Region, Eastern Ethiopia.
1.2. Specific Objectives
1) To determine the seroprevalence of camel brucellosis in the selected districts of the study area.
2) To identify the associated risk factors for camel brucellosis in the selected districts of the study area.
2. Materials and Methods
2.1. Description of the Study Area
This study was conducted in two selected districts of Jarar zone, Somali Regional State of Ethiopia, namely Dagahbur and Dagahmadow. Jarar zone is bordered on the south by Korahey, on the southwest by Nogob, on the northwest by Fafan zone, on the southeast by Dollo, and on the northeast by Somaliland. Dagahbur district is located at 8°13'N latitude and 43°34'E longitude. The altitude of the district ranges from 1044 meters above sea level (m.a.s.l.). It has mean annual minimum and maximum temperatures of 5°C and 38.5°C, respectively. The mean annual rainfall in the area ranges from 300-400 mm. The two prevailing agricultural production systems in the district are pastoral and agro-pastoral production systems
| [25] | Central Statistical Agency of Ethiopia (CSA). Population and Housing Census of Ethiopia. Addis Ababa: CSA; 2007. |
[25]
. The district has a total population of 115,555, out of which about 65,081 are men and 50,474 are women. Most of the total population of the district are rural dwellers.
Dagahmadow district lies between 3- and 15-degrees north latitude and 33- and 48-degrees east longitude. Dagahmadow is bordered on the south and northwest by Fik zone, and on the east by Dagahbur. Based on the 2007 census conducted by the Central Statistical Agency of Ethiopia (CSA), the woreda has a total population of 58,487, of whom 34,199 are men and 24,288 are women
| [25] | Central Statistical Agency of Ethiopia (CSA). Population and Housing Census of Ethiopia. Addis Ababa: CSA; 2007. |
[25]
.
2.2. Study Design
A cross-sectional study was conducted from July 2024 to May 2025 with the aim of investigating the seroprevalence and associated risk factors of brucellosis in camels in selected districts of Jarar Zone, Somali Regional State, Ethiopia.
2.3. Study Population
The study population comprised local breeds of camels kept under extensive management systems in the selected districts of Jarar zone, Somali Regional State, Ethiopia. Individual sampled animal background such as sex, age, herd size, parity, and history of abortion and retained fetal membrane were recorded. Age of animal was determined by dentition and based on information obtained from the owner.
2.4. Sample Size Determination and Sampling Technique
The total study animals were determined according to the formula set by Thrusfield
| [26] | Thrusfield, M. Veterinary Epidemiology. 3rd ed. Oxford: Blackwell Science; 2005. |
[26]
for simple and systematic random sampling, using 95% confidence level and 5% absolute precision. The relevant formula for a 95% confidence interval is:
Where N is required sample size, Pexp is expected prevalence, and d is level of absolute precision (5%). Due to the absence of reports on estimates of the prevalence of antibodies against brucellosis in the study areas, an arbitrary estimate of 50% was chosen to give the maximum sample size. As a result, a total of 384 camels were included for the determination of antibody prevalence against brucellosis.
A multi-stage sampling technique was used to select the study population. Firstly, districts were purposively selected based on camel population, accessibility to vehicles, proximity to livestock markets, and the presence of animal watering sites. However, simple random sampling method was used to select pastoral associations (PAs), commonly called Kebele, from the list provided by the districts' pastoralists development office. PAs with low camel production potential were excluded from the list during random sampling, and a total of three PAs from each district were selected.
2.5. Sample Collection and Laboratory Analysis
2.5.1. Blood Sample Collection and Serum Analysis
Blood samples were collected from each camel under proper restraint to prevent injury and minimize stress. The jugular vein was disinfected before collecting 10 ml of blood in sterile plain vacutainer tubes. The samples were labeled with herd number, sex, and Kebele code and then taken to the laboratory. After 24 hours at room temperature in a slanted position, serum was separated by centrifugation at 1500 rpm for 5 minutes. The serum was then decanted into sterile cryovials, labeled, and stored at −20°C.
2.5.2. Serological Tests
(i). Rose Bengal Plate Test (RBPT)
All serum samples collected were screened using the RBPT, according to the procedures described by Alton et al.
| [27] | Alton, G. G., Jones, L. M., Angus, R. D., Verger, J. M. Techniques for the Brucellosis Laboratory. Paris: Institut National de la Recherche Agronomique; 1990. |
[27]
and the World Organisation for Animal Health
| [28] | World Organisation for Animal Health (OIE). Manual of Diagnostic Tests and Vaccines for Terrestrial Animals. Paris: OIE; 2004. |
[28]
. The antigen used was Rose Bengal antigen, which constitutes a suspension of B. abortus (obtained from the Institute Pourquier, Montpellier, France)
.
Twenty-five microliters of Brucella antigen (reagent) and 75 μl of sample serum was used for camel serum. After four minutes of rocking, any visible agglutination was considered positive
| [28] | World Organisation for Animal Health (OIE). Manual of Diagnostic Tests and Vaccines for Terrestrial Animals. Paris: OIE; 2004. |
[28]
. Agglutinations were recorded as 0, +, ++, and +++, according to the degree of agglutination. A score of 0 indicates the absence of agglutination; + indicates barely visible agglutination; ++ indicates fine agglutination; and +++ indicates coarse clumping. Those samples with no agglutination (0) were recorded as negative while those with +, ++, and +++ were recorded as positive
.
(ii). Competitive Enzyme Linked Immunosorbent Assay (cELISA)
All samples were tested with cELISA as a serial testing with the RBPT. 45 μl of sample dilution buffer was added into each well that would be used for serum samples and controls. 5 microliters of serum control, positive, weak positive, and negative were added into appropriate wells, running each control in duplicate. 5 μl of sample dilution buffer was added into two conjugate controls. 5 μl of tested sample was added in each appropriate well. 50 μl solution was added into all wells used for control and samples. The microplate was covered with adhesive plate sealer and mixed well for 5 minutes on a shaker, then incubated at 37°C for 30 minutes. The plate was rinsed with PBS-Tween Buffer and emptied by removing the fluids. 100 μL substrate solution was added to each well, and the plates were incubated at room temperature (18-25°C). 50 μl of stopping solution was added to each well and mixed thoroughly. Finally, the absorbance of the wells was read with a spectrophotometer at 450 nm within 15 minutes after adding stop solution.
2.6. Method of Data Analysis
All collected data were entered into MS Excel and analyzed using SPSS version 24. Descriptive statistics were used to determine the prevalence of brucellosis, and the risk factors associated with the disease (age, sex, abortion history, herd size, and history of retained fetal membrane) were related using Chi-square test (χ2) for their significant difference at 95% confidence level and p < 0.05 for significance. Logistic regression model was applied to assess associations in univariate and multivariate analysis. Those factors positive in univariate analysis (p = 0.05) were used to develop multivariate logistic regression model to assess multiple associations while controlling confounders.
3. Results
3.1. Characteristics of the Study Animals
This seroprevalence study was conducted in Dagahbur and Dagahmadow districts of Jarar zone, Somali Regional State of Ethiopia. A total of 384 animals from 60 herds were sampled for seroprevalence test of camel brucellosis using RBPT and cELISA. From these 384 animals, 192 (50%) were from Dagahbur district and 192 (50%) from Dagahmadow district. In addition, out of these 384 animals, 34% were adult, 41% were old, and 25% were young animals. Lastly, out of these 384 animals, 19% were male animals and 81% were female animals (
Table 1).
Table 1. Frequency distributions of selected variables describing the study animals at selected districts of Jarar zone, Somali Region, Eastern Ethiopia, 2025 (n = 384).
Variables | Category | Total | Frequency (%) |
District | Dagahbur | 192 | 50 |
| Dagahmadow | 192 | 50 |
Herd size | Small | 73 | 19 |
| Medium | 150 | 39 |
| Large | 161 | 42 |
Age | Young | 95 | 25 |
| Adult | 131 | 34 |
| Old | 158 | 41 |
Sex | Male | 74 | 19 |
| Female | 310 | 81 |
3.2. Seroprevalence and Distribution of Camel Brucellosis in the Study Districts
Camel brucellosis antibodies were detected in 107 camels among 384 examined, giving an overall seroprevalence of 27.86% in RBPT. In addition, confirmatory test was conducted using cELISA, and 3.90% prevalence was found. According to study districts, the result showed that camel brucellosis was more prevalent in Dagahmadow district (4.2%) than in Dagahbur district (3.64%) (
Table 2).
Table 2. Serological prevalence of camel brucellosis in the selected districts of Jarar zone, 2025.
District | No. examined | No. positive RBPT (%) | No. positive ELISA (%) |
Dagahbur | 192 | 70 (36.5) | 7 (3.6) |
Dagahmadow | 192 | 37 (19.3) | 8 (4.2) |
Overall | 384 | 107 (27.7) | 15 (3.9) |
All six villages/kebeles included in the study were found to have animals that were seropositive to camel brucellosis during screening and had a range between 3 and 54.7% seroprevalence rate (
Table 3).
Table 3. Seroprevalence of camel brucellosis by study Kebeles in Jarar Zone, Somali Region, Ethiopia using RBPT.
District | Kebeles | No. examined Animals | No. positive in RBPT test | Prevalence (%) |
Dagahbur | Bulale | 64 | 35 | 54.7 |
| Sasamane | 64 | 22 | 34.4 |
| Garawoo | 64 | 13 | 20.3 |
| Gorayga | 64 | 3 | 4.7 |
| Mudulka | 64 | 18 | 28.1 |
Dagahmadow | Antenka | 64 | 16 | 25.0 |
Overall | | 384 | 107 | 27.86 |
3.3. Associated Risk Factors for Brucellosis in Camels in Jarar Zone
The univariable logistic regression analysis identified reproductive health factors as significant predictors of camel brucellosis in Dagahbur and Dagahmadow districts. Camels with a history of abortion were over five times more likely to test positive for brucellosis (OR = 5.641, p = 0.002), while those with retained fetal membranes had an even higher likelihood, with over six times the odds (OR = 6.569, p = 0.001). Conversely, demographic factors such as sex, age, herd size, district, pregnancy status, and herd parity showed no significant association with infection risk.
Table 4. Univariate Logistic Regression Analysis of Presumptive Risk Factors of Camel Brucellosis in Dagahbur and Dagahmadow Districts.
Variables | Category | No. animals tested | ELISA Test Positive (%) | COR (95% CI) | P value |
Sex | Male | 74 | 2 (2.7) | Ref | |
| Female | 310 | 13 (4.2) | 1.576 (0.348-7.139) | 0.55 |
Age | Young | 95 | 2 (2.1) | Ref | |
| Adult | 131 | 7 (5.3) | 2.625 (0.533-12.928) | 0.23 |
| Old | 158 | 6 (3.8) | 1.836 (0.363-2.284) | 0.45 |
Herd size | <10 Animals | 73 | 3 (4.1) | 1.107 (0.269-4.555) | 0.88 |
| 10-50 Animals | 150 | 6 (4.0) | 1.076 (0.309-3.413) | 0.90 |
| >50 Animals | 161 | 6 (3.7) | Ref | |
Parity | Nulliparous | 126 | 2 (1.6) | Ref | |
| Primiparous | 111 | 7 (6.3) | 4.173 (0.84-20.52) | 0.07 |
| Multifarious | 147 | 6 (4.1) | 2.638 (0.52-13.31) | 0.24 |
Districts | Dagahbur | 192 | 7 (3.6) | 1.14 (0.42-3.23) | 0.79 |
| Dagahmadow | 192 | 8 (4.2) | Ref | |
Pregnancy | Yes | 168 | 4 (2.4) | 2.200 (0.688-7.036) | 0.18 |
| No | 216 | 11 (5.1) | Ref | |
Abortion history | Yes | 45 | 6 (1.3) | 5.641 (1.906-16.694) | 0.002* |
| No | 339 | 9 (2.7) | Ref | |
Retained Fetal | Yes | 40 | 6 (15.0) | 6.569 (2.205-19.568) | 0.001* |
| No | 344 | 9 (2.6) | Ref | |
COR: Crude odds ratio, * Shows significance
The explanatory variables with p ≤ 0.25 in univariable analysis with no multicollinearity were further analyzed using multivariable logistic regression. No significant interactions were detected between variables. The multivariable logistic regression analysis identified several key risk factors associated with camel brucellosis in the districts of Dagahmadow and Dagahbur. Animals with a history of abortion were significantly more likely to be seropositive, with an adjusted odds ratio (AOR) of 2.23 (95% CI: 1.906-16.694, p = 0.002). Similarly, camels that experienced retained fetal membranes showed a markedly increased risk, with an AOR of 6.27 (95% CI: 2.205-19,568, p = 0.001). Overall, the findings emphasize that reproductive health issues, particularly abortion and retained fetal membranes, are strongly associated with increased susceptibility to brucellosis in camels, underscoring the importance of reproductive health management in controlling the disease within these districts (
Table 5).
Table 5. Final Multivariable Logistic Regression Model for Potential Risk Factors of Camel Brucellosis in Dagahmadow and Dagahbur districts.
Variables | Category | No. animals tested | ELISA Test Positive (%) | AOR (95% CI) | P value |
Abortion history | Yes | 45 | 6 (1.3) | 2.23 (1.906-16.694) | 0.002* |
| No | 339 | 9 (2.7) | Ref | |
Retained Fetal | Yes | 40 | 6 (15.0) | 6.27 (2.205-19.568) | 0.001* |
| No | 344 | 9 (2.6) | Ref | |
AOR = Adjusted odds ratio, * Shows significance
4. Discussion
The present study revealed a camel brucellosis seroprevalence of 3.6% in Dagahbur and 4.2% in Dagahmadow districts, with an overall prevalence of 3.90% confirmed by cELISA. This prevalence aligns closely with findings from other regions in Somalia and Ethiopia. For instance, a study in Mogadishu reported a seroprevalence of 4.5% using ELISA
| [30] | Shadia, M., Ahmed, A., Hassan, M. Seroprevalence of brucellosis in camels in Mogadishu, Somalia. Somali Journal of Animal Science. 2017, 4(2), 88-95. |
[30]
, which corroborates our findings. Similar prevalence rates of 4.2% in Borena, Ethiopia
| [22] | Teshome H, Molla B, Tibbo M. A seroprevalence study of camel brucellosis in three camel-rearing regions of Ethiopia. Tropical Animal Health and Production. 2003; 35:381–390. https://doi.org/10.1023/A:1025874310261 |
[22]
, and 4.0% in Niamey, Niger
| [31] | Tanimoun, A., Issa, M., Adamou, M. Seroprevalence of camel brucellosis in Niamey, Niger. Journal of Animal Health and Production. 2021, 9(2), 134-140. |
[31]
, emphasize that camel brucellosis remains a relatively low but persistent health concern in East and West Africa. Additionally, Gizaw et al.
| [21] | Gizaw F, Fentahun G, Mersha S, Bedada H. Seroprevalence and risk factors of brucellosis among camels belonging to selected districts of Afar, Ethiopia: Need for public awareness. American Journal of Microbiological Research. 2017; 5(5): 94–100. https://doi.org/10.12691/ajmr-5-5-1 |
[21]
reported a prevalence of 4.1% in Afar, Ethiopia, further supporting the consistency across different pastoral regions. Conversely, Ghanem et al.
| [32] | Ghanem YM, El-Khodery SA, Saad AA, Abdelkader AH, Heybe A, Musse YA. Seroprevalence of camel brucellosis (Camelus dromedarius) in Somaliland. Tropical Animal Health and Production. 2009; 41(8): 1779–1786.
https://doi.org/10.1007/s11250-009-9377-9 |
[32]
documented a slightly lower prevalence of 3.1% in Somaliland, while higher rates of 8.0% in Kenya
| [33] | Noor, M., Gathura, P., Kiama, S. Seroprevalence of camel brucellosis in Kenya. Journal of Veterinary Research. 2022, 66(2), 201-208. |
[33]
and 10.5% in Nigeria
| [34] | Salisu, U., Adamu, M., Mohammed, A. Seroprevalence of camel brucellosis in Nigeria. Journal of African Veterinary Research. 2018, 9(1), 12-19. |
[34]
highlight that prevalence can vary significantly depending on management practices, disease control measures, and regional factors. The observed variation in seroprevalence across different studies may be attributed to differences in diagnostic tests used, sample sizes, study designs, livestock management systems, and the level of awareness about brucellosis among pastoral communities
| [15] | Megersa B, Biffa D, Abunna F, Regassa A, Godfroid J, Skjerve E. Seroprevalence of brucellosis and its contribution to abortion in cattle, camel, and goat kept under pastoral management in Borana, Ethiopia. Tropical Animal Health and Production. 2011; 43(3): 651–656.
https://doi.org/10.1007/s11250-010-9748-2 |
| [35] | . Bekele M, Mohammed H, Tefera M, Tolosa T. Small ruminant brucellosis and community perception in Jijiga District, Somali Regional State, Eastern Ethiopia. Tropical Animal Health and Production. 2011; 43(4): 893–898.
https://doi.org/10.1007/s11250-011-9781-9 |
[15, 35]
.
The relatively higher seroprevalence detected by RBPT (27.86%) compared to cELISA (3.90%) in this study is noteworthy and consistent with the known limitations of RBPT, which is recognized as a screening test with lower specificity due to its tendency to produce false-positive reactions from cross-reacting antibodies against other Gram-negative bacteria such as
Yersinia enterocolitica O: 9,
Escherichia coli O: 157, and
Salmonella species
| [28] | World Organisation for Animal Health (OIE). Manual of Diagnostic Tests and Vaccines for Terrestrial Animals. Paris: OIE; 2004. |
| [29] | Nielsen K. Diagnosis of brucellosis by serology. Veterinary Microbiology. 2002; 90(1–4): 447–459.
https://doi.org/10.1016/S0378-1135(02)00229-8 |
[28, 29]
. This finding underscores the importance of using confirmatory tests like cELISA, which offers higher specificity and is particularly valuable in endemic regions where cross-reactions are common
| [27] | Alton, G. G., Jones, L. M., Angus, R. D., Verger, J. M. Techniques for the Brucellosis Laboratory. Paris: Institut National de la Recherche Agronomique; 1990. |
| [36] | Godfroid J, Nielsen K, Saegerman C. Diagnosis of brucellosis in livestock and wildlife. Croatian Medical Journal. 2010; 51(4): 296–305. https://doi.org/10.3325/cmj.2010.51.296 |
[27, 36]
. The cELISA has been recommended by the OIE as a confirmatory test for brucellosis diagnosis due to its ability to detect antibodies specifically directed against the smooth lipopolysaccharide (S-LPS) of
Brucella species, minimizing cross-reactivity
| [29] | Nielsen K. Diagnosis of brucellosis by serology. Veterinary Microbiology. 2002; 90(1–4): 447–459.
https://doi.org/10.1016/S0378-1135(02)00229-8 |
| [37] | Mainar-Jaime, R. C., Muñoz, P. M., de Miguel, M. J., Grilló, M. J., Marín, C. M., Moriyón, I., Blasco, J. M. Specificity dependence between serological tests for diagnosing bovine brucellosis in Brucella-free farms showing false positive serological reactions due to Yersinia enterocolitica O:9. Canadian Veterinary Journal. 2005, 46(10), 913-916. |
[29, 37]
. The substantial discrepancy between RBPT and cELISA results observed in this study reinforces the recommendation that epidemiological surveys for brucellosis should employ confirmatory testing to avoid overestimation of true prevalence and to ensure accurate disease burden assessment
| [36] | Godfroid J, Nielsen K, Saegerman C. Diagnosis of brucellosis in livestock and wildlife. Croatian Medical Journal. 2010; 51(4): 296–305. https://doi.org/10.3325/cmj.2010.51.296 |
| [38] | . Ducrotoy MJ, Bertu WJ, Ocholi RA, Gusi AM, Bryssinckx W, Welburn S, Moriyón I. Brucellosis as an emerging threat in developing economies: Lessons from Nigeria. PLoS Neglected Tropical Diseases. 2014; 8(7).
https://doi.org/10.1371/journal.pntd.0003008 |
[36, 38]
.
Regarding reproductive history, although no statistically significant association was observed between parity and seropositivity, seroprevalence was higher in pluriparous camels (5.97%) compared to primiparous ones (1.15%). This trend aligns with previous studies
| [9] | Bekele, M. Brucellosis in livestock and its public health significance in Ethiopia: A review. Ethiopian Veterinary Journal. 2013, 17(2), 1-20. |
| [11] | Angesom, H., Molla, B., Ashenafi, H. Sero-epidemiology of camel brucellosis in the Afar region of Northeast Ethiopia. Journal of Veterinary Medicine and Animal Health. 2013; 5(9): 269–275. https://doi.org/10.5897/JVMAH2013.0235 |
[9, 11]
, which suggest that repeated exposure during successive parturitions and physiological stress may increase the risk of infection. Pluriparous animals are exposed to multiple reproductive cycles, each presenting opportunities for exposure to
Brucella organisms through infected birth materials, aborted fetuses, and contaminated vaginal discharges
| [12] | Musa MT, Eisa MZ, El Sanousi EM, Abdel Wahab MB, Perrett L. Brucellosis in camels (Camelus dromedarius) in Darfur, Western Sudan. Journal of Comparative Pathology. 2008; 138:151–155. https://doi.org/10.1016/j.jcpa.2007.10.005 |
| [39] | Gwida M, El-Gohary A, Melzer F, Khan I, Rösler U, Neubauer H. Brucellosis in camels. Research in Veterinary Science. 2012; 92(3): 351–355. https://doi.org/10.1016/j.rvsc.2011.05.002 |
[12, 39]
. The increased risk in older, multiparous animals may also be attributed to the cumulative probability of exposure over time and the potential for latent infections to become active during periods of physiological stress, such as pregnancy and lactation
| [13] | Corbel, M. J. Brucellosis in Humans and Animals. Geneva: World Health Organization; 2006. |
| [40] | . Seleem MN, Boyle SM, Sriranganathan N. Brucellosis: A re-emerging zoonosis. Veterinary Microbiology. 2010; 140(3–4): 392–398. https://doi.org/10.1016/j.vetmic.2009.06.021 |
[13, 40]
. Furthermore, the management practices in pastoral systems, where animals of different ages and reproductive statuses are often herded together, facilitate the transmission of
Brucella organisms from infected aborting females to susceptible herdmates
| [14] | Minda, A., Gezahegn, M., Belay, N. Challenges in controlling brucellosis in Ethiopian pastoral areas. Journal of Veterinary Science and Technology. 2016, 7(3), 335-342. |
| [19] | McDermott J, Grace D, Zinsstag J. Economics of brucellosis impact and control in low-income countries. Revue Scientifique et Technique (International Office of Epizootics). 2013; 32(1): 249–261. https://doi.org/10.20506/rst.32.1.2197 |
[14, 19]
.
Reproductive disorders such as abortion and retained fetal membranes showed strong associations with seropositivity both in univariable and multivariable analyses in our study. Camels with a history of abortion had over twice the odds of being seropositive (AOR = 2.23, p = 0.002), and those with retained fetal membranes had markedly increased odds (AOR = 6.27, p = 0.001). These findings reinforce the well-established role of reproductive health issues as primary indicators and risk factors for brucellosis, emphasizing the importance of reproductive health management in disease control. Our results are consistent with numerous studies that have documented the strong association between brucellosis and reproductive failures in camels and other livestock species
| [11] | Angesom, H., Molla, B., Ashenafi, H. Sero-epidemiology of camel brucellosis in the Afar region of Northeast Ethiopia. Journal of Veterinary Medicine and Animal Health. 2013; 5(9): 269–275. https://doi.org/10.5897/JVMAH2013.0235 |
| [15] | Megersa B, Biffa D, Abunna F, Regassa A, Godfroid J, Skjerve E. Seroprevalence of brucellosis and its contribution to abortion in cattle, camel, and goat kept under pastoral management in Borana, Ethiopia. Tropical Animal Health and Production. 2011; 43(3): 651–656.
https://doi.org/10.1007/s11250-010-9748-2 |
| [35] | . Bekele M, Mohammed H, Tefera M, Tolosa T. Small ruminant brucellosis and community perception in Jijiga District, Somali Regional State, Eastern Ethiopia. Tropical Animal Health and Production. 2011; 43(4): 893–898.
https://doi.org/10.1007/s11250-011-9781-9 |
[11, 15, 35]
.
Brucella organisms have a predilection for the reproductive tract, particularly the placenta and fetal tissues, where they can cause placentitis, abortion, and retained fetal membranes through the production of erythritol, a sugar that promotes bacterial growth in placental tissues
| [13] | Corbel, M. J. Brucellosis in Humans and Animals. Geneva: World Health Organization; 2006. |
| [40] | . Seleem MN, Boyle SM, Sriranganathan N. Brucellosis: A re-emerging zoonosis. Veterinary Microbiology. 2010; 140(3–4): 392–398. https://doi.org/10.1016/j.vetmic.2009.06.021 |
[13, 40]
. The abortion storm that typically follows the introduction of
Brucella into a susceptible herd results in massive environmental contamination, further perpetuating the transmission cycle
| [19] | McDermott J, Grace D, Zinsstag J. Economics of brucellosis impact and control in low-income countries. Revue Scientifique et Technique (International Office of Epizootics). 2013; 32(1): 249–261. https://doi.org/10.20506/rst.32.1.2197 |
| [39] | Gwida M, El-Gohary A, Melzer F, Khan I, Rösler U, Neubauer H. Brucellosis in camels. Research in Veterinary Science. 2012; 92(3): 351–355. https://doi.org/10.1016/j.rvsc.2011.05.002 |
[19, 39]
. The strong association between retained fetal membranes and brucellosis seropositivity observed in our study is particularly significant, as retention of fetal membranes can lead to secondary infections, reduced fertility, and increased veterinary treatment costs, contributing to substantial economic losses in camel production systems
| [6] | Wernery, U. Camelid brucellosis: a review. Revue Scientifique et Technique (International Office of Epizootics). 2014, 33(3), 839-857. https://doi.org/10.20506/rst.33.3.2322 |
| [16] | Tilahun, B., Tolosa, T., Regassa, A. Knowledge, attitude, and practices of camel herders towards brucellosis in Ethiopia. Journal of Public Health and Epidemiology. 2013, 5(7), 298-305. |
[6, 16]
.
Contrary to expectations, demographic factors such as sex, age, and herd size showed no significant association with brucellosis seropositivity in our study. The lack of association between sex and brucellosis is somewhat surprising given that female camels are generally considered at higher risk due to their reproductive functions and closer contact with infected birth materials
| [9] | Bekele, M. Brucellosis in livestock and its public health significance in Ethiopia: A review. Ethiopian Veterinary Journal. 2013, 17(2), 1-20. |
| [11] | Angesom, H., Molla, B., Ashenafi, H. Sero-epidemiology of camel brucellosis in the Afar region of Northeast Ethiopia. Journal of Veterinary Medicine and Animal Health. 2013; 5(9): 269–275. https://doi.org/10.5897/JVMAH2013.0235 |
[9, 11]
. However, it is plausible that the limited number of male camels sampled (19%) may have reduced the statistical power to detect significant differences between sexes. Additionally, in pastoral management systems, male camels are often used for breeding and may have equal exposure to infected females during mating and herd mixing
| [15] | Megersa B, Biffa D, Abunna F, Regassa A, Godfroid J, Skjerve E. Seroprevalence of brucellosis and its contribution to abortion in cattle, camel, and goat kept under pastoral management in Borana, Ethiopia. Tropical Animal Health and Production. 2011; 43(3): 651–656.
https://doi.org/10.1007/s11250-010-9748-2 |
| [22] | Teshome H, Molla B, Tibbo M. A seroprevalence study of camel brucellosis in three camel-rearing regions of Ethiopia. Tropical Animal Health and Production. 2003; 35:381–390. https://doi.org/10.1023/A:1025874310261 |
[15, 22]
. The absence of a significant association between age and brucellosis in our study contrasts with some previous reports that have identified higher prevalence in older animals
| [21] | Gizaw F, Fentahun G, Mersha S, Bedada H. Seroprevalence and risk factors of brucellosis among camels belonging to selected districts of Afar, Ethiopia: Need for public awareness. American Journal of Microbiological Research. 2017; 5(5): 94–100. https://doi.org/10.12691/ajmr-5-5-1 |
| [35] | . Bekele M, Mohammed H, Tefera M, Tolosa T. Small ruminant brucellosis and community perception in Jijiga District, Somali Regional State, Eastern Ethiopia. Tropical Animal Health and Production. 2011; 43(4): 893–898.
https://doi.org/10.1007/s11250-011-9781-9 |
[21, 35]
. However, our findings align with other studies that have found no age-related differences in seroprevalence
| [20] | Waktole H, Aden M, Ashenafi H. Seroepidemiology of camel brucellosis in and around Dire Dawa, Eastern Ethiopia. Veterinary Medicine International. 2022; 2022: 6624293.
https://doi.org/10.1155/2022/6624293 |
| [33] | Noor, M., Gathura, P., Kiama, S. Seroprevalence of camel brucellosis in Kenya. Journal of Veterinary Research. 2022, 66(2), 201-208. |
[20, 33]
. The lack of association with herd size may reflect the extensive pastoral management systems in the study area, where animals from different herds frequently mix at watering points, grazing areas, and markets, facilitating disease transmission regardless of herd size
| [8] | Zewdie WW. Review on Epidemiology of Camel and Human Brucellosis in East Africa, IGAD Member Countries. Science Journal of Clinical Medicine. 2017; 6:109–115..
https://doi.org/10.11648/j.sjcm.20170606.13 |
| [14] | Minda, A., Gezahegn, M., Belay, N. Challenges in controlling brucellosis in Ethiopian pastoral areas. Journal of Veterinary Science and Technology. 2016, 7(3), 335-342. |
[8, 14]
.
The study's strengths include the use of a comprehensive methodology combining both RBPT and cELISA, which enhances the reliability of the seroprevalence estimates, along with an adequate sample size determined through statistical calculations and a multi-stage random sampling approach that improves representativeness. The identification of key reproductive health-related risk factors, such as abortion and retained fetal membranes, provides valuable insights for targeted control measures. Additionally, the research fills a regional knowledge gap by providing essential epidemiological data on camel brucellosis in the Somali Regional State of Ethiopia, highlighting its public health significance. The study also contributes to the growing body of evidence on camel brucellosis in the Horn of Africa, where camels play a critical role in the livelihoods of pastoral communities
| [1] | Faye, B. How many large camelids in the world? A synthetic analysis of the world camel demographic changes. Pastoralism: Research, Policy and Practice. 2020, 10(1), 25.
https://doi.org/10.1186/s13570-020-00176-z |
| [2] | Masebo, N., Bitew, M., Ayelet, G. Camel population dynamics and health in East Africa. Journal of African Livestock Research. 2023, 12(1), 45-58. |
[1, 2]
. The findings from this study can inform evidence-based policy decisions and guide the development of appropriate control strategies tailored to the local context, considering the unique socio-cultural and economic factors that influence livestock management practices in pastoral areas
| [16] | Tilahun, B., Tolosa, T., Regassa, A. Knowledge, attitude, and practices of camel herders towards brucellosis in Ethiopia. Journal of Public Health and Epidemiology. 2013, 5(7), 298-305. |
| [17] | Addis, M. Public health and economic importance of brucellosis: A review Public Policy and Administration Research. 2015, 14(3), 334-341. |
[16, 17]
.
However, the study has limitations, including its cross-sectional design, which restricts causal inference, and reliance solely on serological tests without bacteriological or molecular confirmation of active infections. Serological methods can also produce false positives due to cross-reactions, possibly overestimating prevalence. Recall bias from owner-reported reproductive histories and the absence of human health data further limit comprehensive understanding of the disease's impact and transmission risks. The cross-sectional nature of the study provides only a snapshot of the disease situation at a single point in time, and does not allow for the determination of temporal relationships between risk factors and infection
| [26] | Thrusfield, M. Veterinary Epidemiology. 3rd ed. Oxford: Blackwell Science; 2005. |
| [41] | Dohoo, I., Martin, W., Stryhn, H. Veterinary Epidemiologic Research. 2nd ed. Charlottetown: VER Inc.; 2009. |
[26, 41]
. Additionally, while cELISA is highly specific, it cannot distinguish between antibodies resulting from natural infection and those produced following vaccination, although vaccination against brucellosis is not commonly practiced in the study area
. The lack of bacteriological isolation and molecular characterization of
Brucella species limits our understanding of the circulating strains and their zoonotic potential
| [12] | Musa MT, Eisa MZ, El Sanousi EM, Abdel Wahab MB, Perrett L. Brucellosis in camels (Camelus dromedarius) in Darfur, Western Sudan. Journal of Comparative Pathology. 2008; 138:151–155. https://doi.org/10.1016/j.jcpa.2007.10.005 |
| [39] | Gwida M, El-Gohary A, Melzer F, Khan I, Rösler U, Neubauer H. Brucellosis in camels. Research in Veterinary Science. 2012; 92(3): 351–355. https://doi.org/10.1016/j.rvsc.2011.05.002 |
[12, 39]
. The reliance on owner-reported reproductive histories may introduce recall bias, as some herders may not accurately recall or report abortion events, particularly in pastoral settings where animals are often managed extensively
| [15] | Megersa B, Biffa D, Abunna F, Regassa A, Godfroid J, Skjerve E. Seroprevalence of brucellosis and its contribution to abortion in cattle, camel, and goat kept under pastoral management in Borana, Ethiopia. Tropical Animal Health and Production. 2011; 43(3): 651–656.
https://doi.org/10.1007/s11250-010-9748-2 |
| [22] | Teshome H, Molla B, Tibbo M. A seroprevalence study of camel brucellosis in three camel-rearing regions of Ethiopia. Tropical Animal Health and Production. 2003; 35:381–390. https://doi.org/10.1023/A:1025874310261 |
[15, 22]
. Furthermore, the absence of human serological data prevents assessment of the true zoonotic burden of brucellosis in the study communities, despite the known risks associated with consumption of raw camel milk and close contact with infected animals
| [16] | Tilahun, B., Tolosa, T., Regassa, A. Knowledge, attitude, and practices of camel herders towards brucellosis in Ethiopia. Journal of Public Health and Epidemiology. 2013, 5(7), 298-305. |
| [17] | Addis, M. Public health and economic importance of brucellosis: A review Public Policy and Administration Research. 2015, 14(3), 334-341. |
[16, 17]
. Future studies should consider incorporating human health surveys, molecular characterization of circulating strains, and longitudinal designs to better understand the transmission dynamics and public health implications of camel brucellosis in this region
| [2] | Masebo, N., Bitew, M., Ayelet, G. Camel population dynamics and health in East Africa. Journal of African Livestock Research. 2023, 12(1), 45-58. |
| [19] | McDermott J, Grace D, Zinsstag J. Economics of brucellosis impact and control in low-income countries. Revue Scientifique et Technique (International Office of Epizootics). 2013; 32(1): 249–261. https://doi.org/10.20506/rst.32.1.2197 |
[2, 19]
.
Despite these limitations, the study provides important baseline data for the development of integrated brucellosis control programs in the Somali Region. Control strategies should focus on improving reproductive health management, enhancing disease surveillance, and promoting public awareness about the risks associated with brucellosis and the importance of pasteurizing camel milk
| [6] | Wernery, U. Camelid brucellosis: a review. Revue Scientifique et Technique (International Office of Epizootics). 2014, 33(3), 839-857. https://doi.org/10.20506/rst.33.3.2322 |
| [13] | Corbel, M. J. Brucellosis in Humans and Animals. Geneva: World Health Organization; 2006. |
[6, 13]
. One Health approaches that involve collaboration between veterinary, medical, and environmental sectors are essential for effective brucellosis control, given the zoonotic nature of the disease
| [19] | McDermott J, Grace D, Zinsstag J. Economics of brucellosis impact and control in low-income countries. Revue Scientifique et Technique (International Office of Epizootics). 2013; 32(1): 249–261. https://doi.org/10.20506/rst.32.1.2197 |
| [36] | Godfroid J, Nielsen K, Saegerman C. Diagnosis of brucellosis in livestock and wildlife. Croatian Medical Journal. 2010; 51(4): 296–305. https://doi.org/10.3325/cmj.2010.51.296 |
[19, 36]
. The importance of a One Health approach is further underscored by the parallel public health threat posed by bacterial contamination of animal-source foods in this region, as evidenced by studies highlighting poor hygiene practices and the isolation of pathogenic
E. coli along the beef value chain in Eastern Ethiopia
| [42] | Mekonnen, A. S., Mumed, B. A., Dawed, A. Food Safety, Isolation and Antibiogram of Escherichia coli Along Beef Value Chain in Chelenko Town, Eastern Ethiopia. European Journal of Clinical and Biomedical Sciences. 2024, 10(4), 57-71.
https://doi.org/10.11648/j.ejcbs.20241004.12 |
[42]
. This reinforces the need for integrated food safety surveillance and hygiene interventions that address multiple zoonotic and foodborne pathogens simultaneously. Community engagement and education are critical components of any control program, as pastoral communities often have traditional beliefs and practices that may influence disease transmission and control
| [16] | Tilahun, B., Tolosa, T., Regassa, A. Knowledge, attitude, and practices of camel herders towards brucellosis in Ethiopia. Journal of Public Health and Epidemiology. 2013, 5(7), 298-305. |
| [35] | . Bekele M, Mohammed H, Tefera M, Tolosa T. Small ruminant brucellosis and community perception in Jijiga District, Somali Regional State, Eastern Ethiopia. Tropical Animal Health and Production. 2011; 43(4): 893–898.
https://doi.org/10.1007/s11250-011-9781-9 |
[16, 35]
. The involvement of local leaders, pastoral development offices, and livestock marketing institutions is crucial for the successful implementation of control measures
| [8] | Zewdie WW. Review on Epidemiology of Camel and Human Brucellosis in East Africa, IGAD Member Countries. Science Journal of Clinical Medicine. 2017; 6:109–115..
https://doi.org/10.11648/j.sjcm.20170606.13 |
| [14] | Minda, A., Gezahegn, M., Belay, N. Challenges in controlling brucellosis in Ethiopian pastoral areas. Journal of Veterinary Science and Technology. 2016, 7(3), 335-342. |
[8, 14]
. Additionally, the development of affordable and accessible diagnostic services, improved veterinary healthcare infrastructure, and effective vaccination programs could significantly reduce the disease burden in camel populations and protect human health
| [6] | Wernery, U. Camelid brucellosis: a review. Revue Scientifique et Technique (International Office of Epizootics). 2014, 33(3), 839-857. https://doi.org/10.20506/rst.33.3.2322 |
| [21] | Gizaw F, Fentahun G, Mersha S, Bedada H. Seroprevalence and risk factors of brucellosis among camels belonging to selected districts of Afar, Ethiopia: Need for public awareness. American Journal of Microbiological Research. 2017; 5(5): 94–100. https://doi.org/10.12691/ajmr-5-5-1 |
[6, 21]
.
In conclusion, camel brucellosis remains a prevalent disease in the Dagahbur and Dagahmadow districts of Jarar zone, with reproductive disorders identified as key risk factors. The strong association between brucellosis and reproductive health issues underscores the importance of reproductive health management in disease control. Coordinated efforts among stakeholders, including veterinary services, public health institutions, pastoral development offices, and community leaders, are needed to implement preventive and control measures. Public awareness campaigns should emphasize the importance of pasteurizing camel milk, proper handling of aborted materials, and seeking veterinary care for reproductive problems. Future research should focus on molecular characterization of circulating Brucella strains, assessment of human brucellosis burden, and evaluation of the effectiveness of different control interventions in pastoral settings. Furthermore, integrated surveillance systems that monitor both zoonotic and foodborne pathogens in livestock products are essential to safeguard public health in these pastoral communities.
5. Conclusions
The current study has shown the distribution of Brucella antibodies in 3.9% of the tested camels in Dagahmadow and Dagahbur districts, in Jarar zone, Somali Regional State of Ethiopia. The risk factors identified for the presence and transmission of the disease from animal to animal were reproductive health factors including history of abortion and retained fetal membranes. The finding of positive serological reactors does not only imply the presence of the disease in the camel population but also indicates the presence of Brucella infection that could serve as a source of infection for the spread of the disease into unaffected animals and herds. This implies that the infected herds' animals and family members are at risk.
Based on the above conclusions, the following recommendations are forwarded to control further spread of the disease:
1) Targeted Control Strategies: There is a pressing need to develop and implement targeted control strategies focusing on reproductive health management to curb the spread of camel brucellosis in this study area. Special attention should be given to the isolation and management of animals with a history of abortion or retained fetal membranes.
2) Regular Screening: Regular screening of camel populations is essential to monitor and control the disease. Early detection through routine testing can prevent further spread.
3) Public Awareness Campaigns: An awareness campaign should be carried out to educate camel owners, herdsmen, and milk consumers about the risks of brucellosis and the health hazards associated with consuming unpasteurized camel milk and its products. The risks of handling aborted materials without protection should also be emphasized.
4) Further Epidemiological Investigations: Further epidemiological investigations are essential, focusing on identifying the specific Brucella species and biotypes responsible for infections in the area. Molecular studies should be conducted to characterize the circulating strains.
5) One Health Approach: Collaborative efforts between veterinary and human health sectors should be strengthened to effectively address the zoonotic implications of camel brucellosis in the region.
Abbreviations
AOR | Adjusted Odds Ratio |
cELISA | Enzyme-Linked Immunosorbent Assay |
CI | Confidence Interval |
COR | Crude Odds Ratio |
CSA | Central Statistical Agency (of Ethiopia) |
ELISA | Enzyme-Linked Immunosorbent Assay |
FAO | Food and Agriculture Organization |
IGAD | Intergovernmental Authority on Development |
m.a.s.l. | Meters Above Sea Level |
NGO | Non-Governmental Organization |
OIE | World Organisation for Animal Health |
OR | Odds Ratio |
PA | Pastoral Association |
PBS | Phosphate-Buffered Saline |
RBPT | Rose Bengal Plate Test |
rpm | Revolutions Per Minute |
S-LPS | Smooth Lipopolysaccharide |
SPSS | Statistical Package for the Social Sciences |
WHO | World Health Organization |
Acknowledgments
We sincerely thank Dr. Isaak Mohamed from the College of Veterinary Medicine, Kabridahar University, for their invaluable mentorship and guidance throughout the research process. We are grateful to Mr. Tasew Ayele for their assistance during sample collection in Dagahbur and Dagahmadow districts, and our appreciation extends to Mr. Abdala Karime and laboratory technicians at the Haramaya University Veterinary Microbiology Laboratory for their technical support in serological testing and data interpretation. We also acknowledge the district pastoralists development offices, the Jarar Zone Livestock and Fishery Development Office, the camel herders who participated in this study, and our field assistants for their cooperation and logistical support.
Author Contributions
Abnet Shewafera Mekonnen: Conceptualization, Data curation, Formal Analysis, Investigation, Methodology, Software, Validation, Visualization, Writing – original draft, Writing – review & editing
Abdirahman Osman Adan: Data curation, Formal Analysis, Investigation, Methodology, Software, Validation, Visualization, Writing – original draft, Writing – review & editing
Yared Adisu Deneke: Formal Analysis, Investigation, Methodology, Software, Validation, Visualization, Writing – original draft, Writing – review & editing
Yusuf Bishar Hussen: Data curation, Formal Analysis, Investigation, Methodology, Software, Validation, Visualization, Writing – original draft, Writing – review & editing
Isaak Sheik Mohamed: Data curation, Formal Analysis, Investigation, Methodology, Software, Validation, Visualization, Writing – original draft, Writing – review & editing
Data Availability Statement
The data is available from the corresponding author upon reasonable request.
Conflicts of Interest
The authors declare no conflicts of interest.
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APA Style
Mekonnen, A. S., Adan, A. O., Deneke, Y. A., Hussen, Y. B., Mohamed, I. S. (2026). Seroprevalence and Associated Risk Factors of Camel Brucellosis in Two Selected Districts of Jarar Zone, Somali Region, Ethiopia. World Journal of Health Services Research, 1(1), 25-34. https://doi.org/10.11648/j.wjhsr.20260101.13
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Mekonnen, A. S.; Adan, A. O.; Deneke, Y. A.; Hussen, Y. B.; Mohamed, I. S. Seroprevalence and Associated Risk Factors of Camel Brucellosis in Two Selected Districts of Jarar Zone, Somali Region, Ethiopia. World J. Health Serv. Res. 2026, 1(1), 25-34. doi: 10.11648/j.wjhsr.20260101.13
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Mekonnen AS, Adan AO, Deneke YA, Hussen YB, Mohamed IS. Seroprevalence and Associated Risk Factors of Camel Brucellosis in Two Selected Districts of Jarar Zone, Somali Region, Ethiopia. World J Health Serv Res. 2026;1(1):25-34. doi: 10.11648/j.wjhsr.20260101.13
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@article{10.11648/j.wjhsr.20260101.13,
author = {Abnet Shewafera Mekonnen and Abdirahman Osman Adan and Yared Adisu Deneke and Yusuf Bishar Hussen and Isaak Shiek Mohamed},
title = {Seroprevalence and Associated Risk Factors of Camel Brucellosis in Two Selected Districts of Jarar Zone, Somali Region, Ethiopia},
journal = {World Journal of Health Services Research},
volume = {1},
number = {1},
pages = {25-34},
doi = {10.11648/j.wjhsr.20260101.13},
url = {https://doi.org/10.11648/j.wjhsr.20260101.13},
eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.wjhsr.20260101.13},
abstract = {Brucellosis is a highly contagious zoonotic disease caused by bacteria of the genus Brucella. Camel brucellosis poses significant public health concerns and hampers socio-economic development in developing countries, particularly in pastoral regions. Despite its endemic status in many areas, limited attention has been given to the disease in camels. This study aimed to determine the seroprevalence and associated risk factors of camel brucellosis in the Dagahbur and Dagahmadow districts of the Jarar zone, Somali Regional State, Ethiopia. A cross-sectional study was conducted from July 2024 to May 2025. A total of 384 camels from six kebeles across the selected districts were included using a multi-stage sampling technique. Serum samples were tested using the Rose Bengal Plate Test (RBPT) and confirmed with Competitive ELISA (cELISA). Logistic regression analysis was performed to identify associated risk factors. The overall seroprevalence was 27.86% by RBPT and 3.9% by cELISA. Camels with a history of abortion were over twice as likely to test positive (AOR = 2.23, p = 0.002), and those with retained fetal membranes had a sixfold increased risk (AOR = 6.27, p = 0.001). Demographic factors such as sex, age, and herd size showed no significant association. Camel brucellosis remains prevalent in the study area, with reproductive disorders identified as key risk factors. Coordinated efforts among stakeholders are needed to implement preventive and control measures, alongside increasing public awareness to curb the spread and reduce disease prevalence.},
year = {2026}
}
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TY - JOUR
T1 - Seroprevalence and Associated Risk Factors of Camel Brucellosis in Two Selected Districts of Jarar Zone, Somali Region, Ethiopia
AU - Abnet Shewafera Mekonnen
AU - Abdirahman Osman Adan
AU - Yared Adisu Deneke
AU - Yusuf Bishar Hussen
AU - Isaak Shiek Mohamed
Y1 - 2026/09/18
PY - 2026
N1 - https://doi.org/10.11648/j.wjhsr.20260101.13
DO - 10.11648/j.wjhsr.20260101.13
T2 - World Journal of Health Services Research
JF - World Journal of Health Services Research
JO - World Journal of Health Services Research
SP - 25
EP - 34
PB - Science Publishing Group
UR - https://doi.org/10.11648/j.wjhsr.20260101.13
AB - Brucellosis is a highly contagious zoonotic disease caused by bacteria of the genus Brucella. Camel brucellosis poses significant public health concerns and hampers socio-economic development in developing countries, particularly in pastoral regions. Despite its endemic status in many areas, limited attention has been given to the disease in camels. This study aimed to determine the seroprevalence and associated risk factors of camel brucellosis in the Dagahbur and Dagahmadow districts of the Jarar zone, Somali Regional State, Ethiopia. A cross-sectional study was conducted from July 2024 to May 2025. A total of 384 camels from six kebeles across the selected districts were included using a multi-stage sampling technique. Serum samples were tested using the Rose Bengal Plate Test (RBPT) and confirmed with Competitive ELISA (cELISA). Logistic regression analysis was performed to identify associated risk factors. The overall seroprevalence was 27.86% by RBPT and 3.9% by cELISA. Camels with a history of abortion were over twice as likely to test positive (AOR = 2.23, p = 0.002), and those with retained fetal membranes had a sixfold increased risk (AOR = 6.27, p = 0.001). Demographic factors such as sex, age, and herd size showed no significant association. Camel brucellosis remains prevalent in the study area, with reproductive disorders identified as key risk factors. Coordinated efforts among stakeholders are needed to implement preventive and control measures, alongside increasing public awareness to curb the spread and reduce disease prevalence.
VL - 1
IS - 1
ER -
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Abdirahman Osman Adan
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