Distribution of brucellosis among small ruminants in the pastoral region of Afar, eastern Ethiopia

Seroprevalence of brucellosis and associated risk factors in camels and its herders in selected districts of Somali Pastoral Region, Eastern Ethiopia

Brucellosis poses a major public and animal health problem in many parts of the world, particularly in pastoral settings, however, seroepidemological studies are scarce. A cross-sectional study was conducted from December 2021 to April 2022 to estimate the prevalence of brucellosis and to identify the associated risk factors for camels and occupational individuals from three purposively selected districts of the Somali pastoral region in Eastern Ethiopia. Serum samples were serially diluted using the Rose Bengal Plate Test (RBPT) as a screening test and a competitive Enzyme-Linked Immunosorbent Assay (cELISA) test as a confirmatory test. From a total of 450 camels and 250 human serum samples tested, the overall seroprevalence was confirmed to be 2.9 % (95 % CI, 1.5-4.9) in camels and 2.0 % (95 % CI, 0.2-3.7) in humans. In camels, abortion and retained fetal membrane (RFM) were significant risk factors for Brucella seropositivity (p<0.05). However, in humans, RFM disposal differed significantly (p<0.05). The fact that brucellosis is found in both camels and humans highlights the importance of implementing a coordinated One Health approach to control and eliminate the disease. This would ensure improved public health and increased livestock productivity.

Seropositivity, Comparison Between the Efficiency of Serological Tests and Risk Factors of Brucella Infection in Small Ruminants with History of Abortion in the Afar Region of North-Eastern Ethiopia

Purpose

Brucellosis is one of the most important reproductive diseases that cause abortion and breeding failure in small ruminants in Ethiopia. Therefore, our objective was to detect the seropositivity and risk factors of Brucella infection in small ruminants with history of abortion using modified RBPT, cELISA, and CFT in the Amibara district of the Afar Region, Ethiopia.

Methods

Sera were collected from 226 animals (195 goats and 31ewes) and assessed for seropositivity of Brucella infection using modified RBPT, CFT, and competitive ELISA.

Results

The overall seroprevalence was 12.0% (27 out of 226), 7.5% (17 out of 226), and 26.5% (60 out of 226) by mRBPT, CFT, and cELISA, respectively. Out of 27 sera that were reactive by mRBPT, 17 (63.0%) were also reactive by (CFT). Out of the 17 sera that were reactive by CFT and mRBPT, 14 (82.4%) were reactive by cELISA. Out of the 29 sera that were non-reactive by both mRBPT and CFT, 10 (34.5%) were found reactive by cELISA. Out of the 226 sera that were tested by both mRBPT and cELISA, 20 (8.9%) were reactive by both tests, while 159 (70.4%) were non-reactive by both tests. The percentage of test agreement (79.2%) between mRBPT and cELISA was poor (k=0.353). High seropositivity for Brucella infection was significantly associated with the presence of retained placenta in the studied animals (adjusted OR=2.2, 95% CI, 1.1-4.4, P=0.030) as detected by cELISA.

Conclusion

The current study revealed that a cELISA-based seroepidemiological survey increases the likelihood of detecting individuals with brucellosis and provides reliable evidence for mRBPT. Furthermore, there was a significant association between seropositivity for Brucella infection and retained placenta. These findings emphasize the necessity for proactive measures to reduce the economic impact of brucellosis and mitigate the risk of zoonotic transmission.

Herd and animal level seroprevalence and associated risk factors of small ruminant brucellosis in the Korahey zone, Somali regional state, eastern Ethiopia

Introduction

Brucellosis is a zoonosis of major public health and economic importance that is endemic in livestock in Ethiopia with varying levels of seroprevalence.

Methods

A cross-sectional study was carried out to determine the individual and herd-level seroprevalence of brucellosis in small ruminants in the Korahey zone of the Ethiopian Somali Region. A total of 324 sera from 63 herds of small ruminants were collected randomly using a multistage sampling technique and the sera were tested using the Rose Bengal Plate Test, and seropositive reactors were confirmed by the Complement Fixation Test.

Results and discussion

The seroprevalence of brucellosis at the herds and the individual level was 6.35% (95% CI: 0.0-13%) and 1.23% (95% CI: 0.0-2%), respectively; with 1.4% in goats and 0.9% in sheep. Moreover, predicted variables like age group, parity, history of abortion, fetal membranes, herd size, ownership of other livestock species, contact with wild animals in the past year, the introduction of new animals in the past year, and lending of breeding males in the past year were not significantly associated (p > 0.05) with Brucella seropositivity at individual and herd level seroprevalence during multivariable logistic regression analysis. Pastoral community awareness regarding the public health impact of brucellosis and the promotion of an intersectoral One Health approach for the effective control of brucellosis is recommended.

Comparative evaluation of RBPT, I-ELISA, and CFT for the diagnosis of brucellosis and PCR detection of Brucella species from Ethiopian sheep, goats, and cattle sera

BACKGROUND

Brucellosis is an economically devastating animal disease and has public health concern. Serological methods such as Rose Bengal Plate Test (RBPT), Complement Fixation Test (CFT), and Indirect-Enzyme-Linked Immunosorbent Assay (I-ELISA) have been used to detect brucellosis. However, there is limited comparative evaluation studies and lack of molecular confirmation of the causative agents in the study areas. The study was aimed to compare RBPT, I-ELISA, CFT, and confirmation using Polymerase Chain Reaction (PCR). A total of 2317 sera samples were collected from brucellosis-affected areas of Ethiopia with no vaccination history. All sera were subjected to comparative serological assays. Post-cross tabulation, sensitivity, and specificity were determined using Receiver Operating Characteristics (ROC) curve analysis software. PCR was performed on 54 seropositive samples using genus- and species-specific primers.

RESULTS

Among the 2317 sera tested for comparative serological assays, 189 (8.16%) were positive for RBPT, 191 (8.24%) for I-ELISA, and 48 (2.07%) for CFT. Sensitivity to RBPT was 100% (95%) in shoats and 74% (95%) in cattle. Specificity on RBPT was 98.69% (95%), 99.28% (95%), 100% (95%) in sheep, goats, and cattle, respectively. CFT sensitivity was 4 (95%) in sheep, 9.65 (95%) goats, and 72 (95%) cattle. Specificity on CFT was 100% (95%) for sheep, goats, and cattle. A 223bp Brucella genus-specific and 156bp B. abortus species-specific detected. However, B. melitensis not detected.

CONCLUSION

In this study, I-ELISA was the most sensitive and specific test. RBPT detected all Brucellosis-infected sheep and goats; nevertheless, it showed false positive in sheep and goats and false negative in cattle. The presence of B. abortus in small and large ruminants was confirmed by PCR. This is the first report of B. abortus detection in small ruminant in Ethiopia. B.abortus detected in non-preferred hosts. The findings suggest further study on molecular epidemiology of Brucella species.

Study on small ruminant brucellosis and owners awareness in two selected districts of southern region, Ethiopia

INTRODUCTION

Brucellosis is one of the infectious diseases that has the greatest impact on the productivity of sheep and goats. A cross-sectional study followed by a simple random sampling technique was used to investigate the seroprevalence of brucellosis (Rose Bengal plate test; RBPT and complement fixation test; CFT) in small ruminants and its related risk variables from November 2019 to June 2020 in Kolme and Abala Abaya districts. A questionnaire was also given to owners to assess their existing knowledge of the disease.

RESULT

Using the RBPT and CFT, 28 (4.1%) and 23 (3.33%) of the 690 animals were found to be seropositive for brucellosis, respectively. In this study, the seroprevalence of brucellosis detected in the Kolme district (5.3%) was greater when compared to Abala Abaya (1.0%). The odds of Brucella infection were greater for goats (odds ratio [OR] 6.0, 95% confidence interval [CI] 16 0.8-44.9) than for sheep. The odds of adult animals (OR 0.05, 95% CI 0.03-0.07) being positive for brucellosis was higher than young animals. A statistically significant difference in the seropositivity of brucellosis was detected in univariate logistic regression among districts, different age groups, herd size, parity number, and reproductive health problems except for species and sex, but in multivariate logistic regression, only reproductive health problems were revealed a statistically significant difference. Out of 138 families, 100% of respondents were unaware of brucellosis, 94.5% drink raw milk, and 74% handle animals with retained fetal membranes with their bare hands.

CONCLUSION

This study showed that brucellosis was a widely spread disease in the study areas and poses a substantial public health danger. To reduce the spread of the disease in small ruminants, public health risks, and economic losses, stringent vaccination application and awareness of personal hygiene are critical.

Apparent prevalence of brucellosis, Q-fever and toxoplasmosis in aborted goat’s at North Shoa, Ethiopia

Abortion imposes great economical loss in productivity and by product of small ruminants. The present study was conducted to determine the rate of abortion and apparent prevalence of Brucellosis, Toxoplasmosis and Q-fever in aborted goats from June 2015 to August 2019 in North Shoa, Ethiopia. During consecutive years of clinical case study 503 does were entered to mating, of which100 (19.5 %) animals aborted. There were significant differences (p=0.013) in abortion among parities. A total of 35 serum samples were collected from aborted does within six months periods. All samples were screened initially with Rose Bengal plate test (RBPT) for Brucellosis. All RBPT positive were further tested by i-ELISA. Also, serums were tasted to screen specific antibody against Q-fever and Toxoplasmosis using i-ELISA. Of total tested 64.7 % and 8.6 % of them were positive for Q-fever and Toxoplasmosis, respectively, but neither of them was positive for Brucellosis. The present clinical study revealed that abortion was the cause of kids’ loss and serological investigation of antibody against Q-fever and Toxoplasmosis showed that the agents were the major causes of abortion. Even though there was no positive reactor does to brucellosis, the result must be interpreted with care since absence of evidence is not evidence of absence. Beside of this, some samples collected from active cases were sero-negative for neither of tested antibodies; it indicated there was other cause/s of abortion in the study site. These interesting findings deserve further detail study by using more sensitive diagnostic test in order to examine the full extent of the problem in small ruminant populations. Also, an awareness-raising campaign should be launched to educate farm workers and professionals about proper preventive and control measures for such zoonotic diseases

Risk factors for Brucellosis and knowledge-attitude practice among pastoralists in Afar and Somali regions of Ethiopia

BACKGROUND

Brucellosis is a neglected bacterial zoonotic disease with substantial economic impact on households. Pastoral communities are a potential risk group due to their way of life being closely interlinked with their large livestock herds.

METHODOLOGY

A semi-structured questionnaire survey was conducted in households in the pastoral Afar and Somali (SRS) regions. All households had people and animals serologically tested for brucellosis. Questions were related to husbandry, consumption habits, and knowledge-attitude-practice towards the disease and zoonoses. Descriptive statistics and logistic analysis were performed to assess potential risk factors for having households with positive humans and/or animals.

RESULT

647 households were included in the survey. Herd brucellosis prevalence was 40.3 % (15.9-86.3 % in Afar; 4-72.2 % in SRS). Over half (56.3 %) of the households in Afar and 41.8 % in SRS had at least one human reactor. Nearly a quarter of the households (22.8 %), recalled abortions in goats in the last 12 months, whereas 52.5 % and 50.3 % recalled stillborn in all species and membrane retentions respectively. All respondents drank raw milk and discarded animal afterbirths in the direct surroundings with minimal protection. Risk factors for animal reactors were goat herd size, and goat abortion. There was no identified risk factor for having human reactors in households. None of the households knew about brucellosis.

CONCLUSION

Although being endemic in Afar and SRS, Brucellosis is not known by the pastoralists. Brucellosis control programs will have to be tailored to the pastoral context, accounting for their mobility, large, multi-species herds and habits.

Integrated human-animal sero-surveillance of Brucellosis in the pastoral Afar and Somali regions of Ethiopia

Background

Brucellosis is widespread in Ethiopia with variable reported prevalence depending on the geographical area, husbandry practices and animal species. However, there is limited information on the disease prevalence amongst pastoral communities, whose life is intricately linked with their livestock.

Methodology

We conducted an integrated human-animal brucellosis sero-surveillance study in two adjacent pastoral regions, Afar and Somali region (SRS). This cross-sectional study included 13 woredas (districts) and 650 households. Blood samples were collected from people and livestock species (cattle, camel, goats and sheep). Sera were analyzed with C-ELISA for camels and shoats (sheep and goats), with I-ELISA for cattle and IgG ELISA for humans. Descriptive and inferential statistics analyses were performed.

Results

A total of 5469 sera were tested by ELISA. Prevalence of livestock was 9.0% in Afar and 8.6% in SRS (ranging from 0.6 to 20.2% at woreda level). In humans, prevalence was 48.3% in Afar and 34.9% in SRS (ranging from 0.0 to 74.5% at woreda level). 68.4% of all households in Afar and 57.5% of households in SRS had at least one animal reactor. Overall, 4.1% of animals had a history of abortion. The proportion of animals with abortion history was higher in seropositive animals than in seronegative animals. Risk factor analysis showed that female animals were significantly at higher risk of being reactors (p = 0.013). Among the species, cattle had the least risk of being reactors (p = 0.014). In humans, there was a clear regional association of disease prevalence (p = 0.002). The older the people, the highest the odds of being seropositive.

Conclusion

Brucellosis is widespread in humans and animals in pastoral communities of Afar and SRS with the existence of geographical hotspots. No clear association was seen between human and particular livestock species prevalence, hence there was no indication as whether B. abortus or B. melitensis are circulating in these areas, which warrants further molecular research prior to embarking on a national control programs. Such programs will need to be tailored to the pastoral context.

Brucellosis is a neglected disease of livestock that can be transmitted to people through consumption of raw animal products and direct contact with animal birth material. Although prevalent in Ethiopia, there is limited information on the disease prevalence amongst pastoral communities, whose life is intricately linked with their livestock. We therefore, conducted a disease surveillance in people and their livestock in Afar and Somali region (SRS), two pastoral regions of Ethiopia. The study included 13 districts and 650 households. A total of 5469 blood samples were collected from people and livestock species (cattle, camel, sheep and goats) and analyzed using commercial brucellosis ELISA assays. Livestock brucellosis prevalence was 9% in Afar and 8.6% in SRS (ranging from 0.6 to 20.2% at woreda level). In humans, prevalence was 48.3% in Afar and 34.9% in SRS (ranging from 0 to 74.5% at woreda level). 68.4% of all households in Afar and 57.5% of households in SRS had at least one positive animal. This study showed that the disease is widespread in human and their livestock in pastoral communities of Afar and SRS with the existence of geographical hotspots. Results will advise on tailored surveillance programs in pastoral communities.

Seroprevalence and Risk Factors of Small Ruminant Brucellosis in West Hararghe Zone of Oromia Regional State, Eastern Ethiopia

A cross-sectional study design was employed on collected sera samples to investigate brucellosis in small ruminants from December 2018 to November 2019 with the objectives of estimating the seroprevalence and potential risk factors for the occurrence of brucellosis in small ruminants in selected districts of West Hararghe: Chiro, Hirna, and Mieso. A total of 2070 collected sera samples from small ruminants were tested using serological tests and screened by RBPT and confirmatory test (CFT). The overall seroprevalence of the present study was 0.24% in small ruminants (Chiro 0.2%, Hirna 0%, and Mieso 0.3%). The chi-square test (Stat 14.0) was used to determine the strength of potential risk factors associated with the occurrence of brucellosis by using univariable logistic regression. Mixed flock (OR = 2.11 (1.33–3.36 CI; P=0.002)), agropastoral (OR = 4.01 (2.35–6.84 CI; P=0.0001)) and pastoral (OR = 2.59 (1.37–4.90 CI; P=0004)) production system, and larger flock size (OR = 1.68 (1.08–2.60 CI; P=0.021) were factors significantly affecting the prevalence of small ruminant brucellosis. Univariable analysis was used, and independent predictors of small ruminant brucellosis were further analyzed using multilogistic regression. This disease was presented in the current study area; therefore, the careful separation of positive animals would help to prevent and control further distribution of the disease.

Prioritizing smallholder animal health needs in East Africa, West Africa, and South Asia using three approaches: Literature review, expert workshops, and practitioner surveys

Managing the health needs of livestock contributes to reducing poverty and improving the livelihoods of smallholder and pastoralist livestock keepers globally. Animal health practitioners, producers, policymakers, and researchers all must prioritize how to mobilize limited resources. This study employed three approaches to prioritize animal health needs in East and West Africa and South Asia to identify diseases and syndromes that impact livestock keepers. The approaches were a) systematic literature review, b) a series of expert workshops, and c) a practitioner survey of veterinarians and para-veterinary professionals. The top constraints that emerged from all three approaches include endo/ ectoparasites, foot and mouth disease, brucellosis, peste des petits ruminants, Newcastle disease, and avian influenza. Expert workshops additionally identified contagious caprine pleuropneumonia, contagious bovine pleuropneumonia, mastitis, and reproductive disorders as constraints not emphasized in the literature review. Practitioner survey results additionally identified nutrition as a constraint for smallholder dairy and pastoralist small ruminant production. Experts attending the workshops agreed most constraints can be managed using existing veterinary technologies and best husbandry practices, which supports a shift away from focusing on individual diseases and new technologies towards addressing systemic challenges that limit access to veterinary services and inputs. Few research studies focused on incidence/ prevalence of disease and impact, suggesting better incorporation of socio-economic impact measures in future research would better represent the interests of livestock keepers.

Brucellosis in ruminants and pastoralists in Borena, Southern Ethiopia

Brucellosis is a bacterial zoonotic disease that has important veterinary and public health consequences as well as economic impact in sub Saharan Africa including Ethiopia. A cross-sectional study was conducted in four selected districts of Borena Pastoral setting in Southern Ethiopia from October 2017 to February 2018 to estimate the prevalence of brucellosis and assess associated risk factors in cattle, sheep, goats and occupationally associated humans. A total of 750 cattle, 882 sheep and goats and 341 human subjects were screened for evidence of brucellosis using the Rose Bengal Test (RBT) with positive results confirmed by Competitive-ELISA(c-ELISA). Structured questionnaires were used for collection of metadata from individual animals, herders and animal attendants to test the association between explanatory and outcome variables. The overall animal level prevalence was 2.4% (95% confidence interval, CI: 1.4-3.7) in cattle, 3.2% (95% CI: 2.1-4.6) in sheep and goats, and 2.6% (95% CI: 1.2-5) in humans occupationally linked to livestock production systems. Herd size, parity, and history of abortion were risk factors associated with Brucella seropositivity (P<0.05) in cattle whereas in sheep and goats the results showed that district, age group, flock size, and history of abortion were significantly associated risk factors with Brucella seropositivity (P<0.05). Assisting calving and presence of seropositive animals in a household (P<0.05) were significantly associated with Brucella seropositivity in humans. Evidence of brucellosis in various animal species and the associated human population illustrates the need for a coordinated One Health approach to controlling brucellosis so as to improve public health and livestock productivity.

Isolation and identification of Brucella melitensis using bacteriological and molecular tools from aborted goats in the Afar region of north-eastern Ethiopia

BACKGROUND

Infection with Brucella melitensis (B. melitensis) is one of the most important causes of abortion in goats and sheep, and also causes severe systemic disease in exposed humans. In Ethiopia, based on seroepidemiological studies, brucellosis is known to be endemic. However, there is little information on the isolation and molecular detection of Brucella species in small ruminants. Therefore, the present study was conducted in the Amibara district of Afar Region of Ethiopia to isolate and molecularly detect Brucella infection in small ruminants.

RESULTS

Out of the total 64 samples cultured, eight samples (five vaginal swabs and three milk) were positive for Brucella species based on colony morphology, growth characteristics, modified acid fast staining and biochemical tests results. Further identification using Brucella- ladder PCR method showed that four of the isolates (three from vaginal swabs and one from milk) from goats amplified fragments of 1071 bp, 794 bp, 587 bp, 450 bp and 152 bp in band size. The molecular result combined with the microbiological and biochemical characteristics of the isolates indicated that the isolates were strains of B. melitensis.

CONCLUSION

The finding of this study could suggest economic and zoonotic significance of B. melitensis and warrants for the need for control strategies in livestock and creation of awareness in the pastoral communities on the safe consumption of foods of animal origin and avoidance of physical contact with aborted materials.

Sero-prevalence and community awareness on the risks associated with Livestock and Human brucellosis in selected districts of Fafan Zone of Ethiopian-Somali National Regional State

A cross-sectional study was conducted to estimate the sero-prevalence, potential risk factors for transmission and spread of brucellosis in livestock and human in Jigjiga and Gursum Woredas of Fafan Zone in Ethiopian-Somali. Two Kebeles were purposively selected from each Worada based on accessibility and willingness of livestock owners. For serology, a total of 268 cattle, 108 sheep, 172 goats, 183 camels, 211 humans were included. For questionnaire, 99 volunteers were recruited. Blood samples were collected from livestock and human. The serum was subjected to Rose Bengal Plate Test (RBPT) and Complement Fixation Test (CFT) to detect Brucella antibody. Out of the total 731 livestock examined, 3.0% were positive for Brucella antibodies using RBPT. Highest sero-prevalence was recorded in camels (4.9%) followed by goat (2.9%), cattle (2.6%), and sheep (0.9%). Using CFT, 0.4% of animals were found positive for brucellosis. A sero-prevalence of 1.7% was recorded in goats using CFT but no in other animal species. From the 211 human serum samples, 5 (2.4%) were positive for Brucella infection using RBPT. One (0.4%) was confirmed by CFT. Questioner survey revealed, almost all respondents (98%) were not aware about zoonotic risks of brucellosis. Cattle and camel milking were mainly performed by housewives. Although 97-99% of respondent had habits of cooked meat consumption, the majorities (99%) consume raw milk. In the pastoral community, the observed sero-prevalence of human brucellosis along with the practices of animal husbandry and animal food consumption habits, might give an insight that brucellosis could pose a public health hazard.

Knowledge and perception of pastoral community members about brucellosis as a cause of abortion in animals and its zoonotic importance in Amibara district, Afar Region, Ethiopia

Sero-epidemiological studies of brucellosis in the Afar Region showed that the disease is prevalent in livestock. However, there is little information regarding the pastoral community members’ awareness about brucellosis as a cause of abortion in animals and its zoonotic importance. In this study, we assessed knowledge and perception of pastoral community members about brucellosis as a cause of abortion in animals and its zoonotic importance in Amibara district, Afar Region, Ethiopia. Between October and December 2016, a total of 475 study participants (age range 18–80 years, mean age 35.9 years) were interviewed about abortion in their animals, its causes, and diseases that can be transmitted to humans through consumption of raw milk. Almost all (97.7%) of the study participants reported that abortion in animals, especially in goats, is a major problem in the area, and they mentioned that disease (44.6%), drought (58.4%) and fly bites (29.5%) as the main causes of abortion. The study participantsalso thought that malaria (42.9%) and bovine tuberculosis (19.3%) can be transmitted to humans through consuming raw milk. Five respondents (4.2%) mentioned brucellosis (locally known as “hahayita”) as a disease that can be transmitted through frequent consumption of raw milk. The majority (91.9%) mentioned malaria as a cause of febrile illness in humans and 16 (4.4%) participants mentioned brucellosis as a cause of febrile illness. Some participants also mentioned brucellosis as a cause of joint swelling (hygroma) in cattle. In conclusion, the pastoral community members in the present study area lack clear understanding about brucellosis as one of the diseases that cause abortion in their animals and its zoonotic importance. There is a need to create awareness about the zoonotic and animal health importance of brucellosis through various means such as community health extension/veterinary workers and community leaders.

Seroprevalence of Brucellosis and Associated Risk Factors among Indigenous Breeds of Goats in Wukari, Taraba State, Nigeria

A cross-sectional study was conducted in Wukari, Taraba state, Nigeria, to determine the prevalence of Brucella antibodies and the risk factors associated with brucellosis in indigenous breeds of goats. A total of 386 goats were sampled from three political wards: Puje, Avyi, and Hospital: harvested sera samples were subjected to Rose Bengal Plate Test (RBPT). GraphPad Prism version 7.03 for Windows (GraphPad Software, La Jolla California, USA) was used to analyse the association between seroprevalence of brucellosis and age, sex, breed, location, and management system by using Chi square and Fisher's exact test as appropriate. Brucellosis was detected in all three wards: Puje; 15%, Avyi; 6.6%, and Hospital; 7.6%. A prevalence rate of 2.8%, 8%, 18.7%, and 1% was recorded for <20-month, 22-35-month, 36-45-month, and ≥46-55-month age categories, respectively (P < 0.05). Only 9.5% was observed for male animals while 9.8% was observed for female animals with no statistical difference between the males and females. Breed-specific seroprevalence yielded 7.4%, 5.4% 12%, 12.8%, and 11.6%, for Cross, West Africa Dwarf, Red Sokoto, Kano Brown, and Sahel breeds of goat, respectively. There is an evidence of brucellosis (9.6%) in Wukari L.G.A, Taraba State, and age is a risk factor for the disease in the study area. There is a need to enlighten the public on the zoonotic potentials and economic impacts of brucellosis.

Seroprevalence of brucellosis in small ruminants in organized and unorganized sectors of Gujarat state, India

Aim:

The present study aimed to study the seroprevalence of brucellosis in small ruminants of Gujarat state, India, using Rose Bengal Plate test (RBPT) and indirect enzyme-linked immunosorbent assay (iELISA).

Materials and Methods:

A total of 2444 sera samples (675 sheep and 1769 goat) from unorganized sector and 1310 sera samples (861 sheep and 449 goat) from seven organized farms were collected for brucellosis screening.

Results:

In unorganized sector, 23.70% sheep (160/675) and 15.99% goat (283/1769) were positive by RBPT and 24.44% sheep (165/675) and 17.24% goat (305/1769) by iELISA. The organized sector samples showed higher seroprevalence in goat (7.79 %, 35/449) than sheep (4.06 %, 35/861) by RBPT. Similarly, in iELISA, goat samples showed a higher seroprevalence (9.35%, 42/449) compared to sheep (7.50%, 65/861). The diagnostic sensitivity and specificity of RBPT with ELISA were 88.69% and 99.65%, respectively, and showed a significant difference (p≤0.0001). The Chi-square analysis revealed a significant difference in seroprevalence between sectors (p≤0.01) and species (p≤0.01).

Conclusion:

The seroprevalence of brucellosis in small ruminants of Gujarat was investigated and showed a higher prevalence of brucellosis and warrants the implementation of proper preventive measures.

Comparative Seroepidemiological Study of Brucellosis in Sheep under Smallholder Farming and Governmental Breeding Ranches of Central and North East Ethiopia

This cross-sectional study was carried out to investigate the status of brucellosis in sheep management under extensive smallholder farming and intensively in governmental breeding ranches in six districts selected from three administrative zones. Using multistage sampling, serum samples of 2409 sheep from 274 flocks were collected and tested using the Rose Bengal Plate Agglutination Test (RBPT) and positive sera were confirmed using a Complement Fixation Test (CFT). Of all animals tested, 4.98% were RBPT positive, and after confirmation with CFT, the overall animal-level prevalence was found to be 4.89% (CI: 3.24-6.9%). Of the flocks sampled, 61 (22.3%, CI: 18.03-29.17%) had at least one animal positive to both tests. Significantly higher (P < 0.001) individual animal seroprevalence of 5.87% (CI: 3.83-7.31%) was found in sheep under smallholder production than in breeding ranches (1.75%, 95% CI: 1.57-3.05%). However, flock level seroprevalence in breeding ranches was found to be 100% (8/8), while in the smallholder production it was 19.92% (CI: 16.4-25.81%). Significantly highest animal-level seroprevalence of 9.55% (CI: 7.91-12.4%) was observed in north Wollo zone's smallholder farms. From the three studied breeding ranches, highest seroprevalence of 3.57% (CI: 2.84%-5.18%) was found in Sheno Agricultural Research Centre. Significantly higher seroprevalence (P < 0.01) was found in aborted sheep and with history of retained fetal membrane in both production systems. All the sheep flocks in the studied breeding ranches were found to be seropositive; hence, this study suggests strict control measures of ovine brucellosis in the breeding reaches, since they could be a source of infection for the smallholder farms.

Seroprevalence and risk factors of caprine brucellosis in Khartoum state, Sudan

Aim

This cross-sectional study was conducted from April to July 2012 in Khartoum state, Sudan, to determine the seroprevalence of brucellosis in goats and to investigate potential risk factors associated with this disease.

Materials and Methods

A total of 307 serum samples were collected from both sexes of goats in four different localities and were subjected to testing for brucellosis using rose bengal plate test (RBPT), serum agglutination test (SAT), and competitive enzyme-linked immunosorbent assay (cELISA).

Results

The overall seroprevalence was 11.4% (n=35) with a 95% confidence interval (CI) ranging from 7.80 to 15.0. Out of these 35 RBPT-positive samples, the positivity of 18 and 17 were confirmed by SAT and cELISA, respectively. A significant statistical variation was observed between brucellosis seroprevalences in goats purchased from local animal markets and goats that were raised at the farm. Conversely, such significant variations were not observed among the categories of other risk factors with seroprevalences ranging from 3.0% (95% CI between 0.40 and 7.20) to 16.3% (95% CI between 10.4 and 22.3). Location (χ²=9.33, df=3, p=0.02), breed (χ²=3.52, df=1, p=0.05), herd size (χ²=6.59, df=2, p=0.03), and herd expansion (χ²=5.39, df=1, p=0.02) were associated with RBPT-positive status for brucella in the two-tailed Chi-square test. In addition, Sharq an-Nil locality and goats raised at the farm had increased odds of being RBPT positive.

Conclusion

Brucellosis was detected in goats in all surveyed localities. An effort should be made to educate goat owners/herders about brucellosis as well as about the importance of vaccination.

Cross-sectional survey of brucellosis and associated risk factors in the livestock-wildlife interface area of Nechisar National Park, Ethiopia

A cross-sectional survey was carried out to investigate the seroprevalence of ovine and bovine brucellosis in the livestock-wildlife interface area of Nechisar National Park, Ethiopia. Furthermore, producer's knowledge about brucellosis and its zoonotic potential was assessed using a structured questionnaire. A total of 268 cattle and 246 goat sera were collected from 50 herds and 46 flocks and subjected to Rose Bengal test (RBT) and enzyme-linked immunosorbent assay (ELISA) in parallel to detect anti-Brucella species antibodies. Positive reactions were further confirmed with compliment fixation test (CFT). Flock and herd level seroprevalence rate was 12.8% (95% CI 4.8-25.7) and 32.0% (95% CI 19.5-46.7) in goats and cattle, respectively. An overall animal-level seroprevalence of 4.5% (95% CI 2.25-7.86) and 9.7% (95% CI 6.44-13.89) was recorded for goats and cattle, respectively. Seroprevalence showed an increasing trend with age, where adult cattle > 2 years. Goats (> 1 year) recorded relatively higher seroprevalence, but the differences were not statistically significant. Similarly, female cattle and goats recorded a relatively higher seroprevalence, 11 and 5.6%, respectively, compared to males but the difference was not significant. However, a significant (P < 0.01) variation of seroprevalence was noted for parity (bovine), higher in animals in second parity, and abortion history, in both species, higher in animals that experienced abortion. Interviews revealed lack of awareness about brucellosis and food safety related to the zoonotic potential from consuming raw animal products (milk and meat). Ninety-eight percent of respondents did not consider handling abortion material is risky, and only a very low proportion (8%, n = 50) was able to mention limited zoonotic diseases (anthrax and Taenia cysticercosis) could be transmissible to people. The study indicated that brucellosis is endemic in domestic animals in the interface area and calls for further broad epidemiological investigation of the disease in livestock, human and wildlife following 'one health' unified research approaches beside enhancing public awareness.

Brucellosis in Sub-Saharan Africa: Current challenges for management, diagnosis and control

Brucellosis is a highly contagious zoonosis caused by bacteria of the genus Brucella and affecting domestic and wild mammals. In this paper, the bacteriological and serological evidence of brucellosis in Sub-Saharan Africa (SSA) and its epidemiological characteristics are discussed. The tools available for the diagnosis and treatment of human brucellosis and for the diagnosis and control of animal brucellosis and their applicability in the context of SSA are presented and gaps identified. These gaps concern mostly the need for simpler and more affordable antimicrobial treatments against human brucellosis, the development of a B. melitensis vaccine that could circumvent the drawbacks of the currently available Rev 1 vaccine, and the investigation of serological diagnostic tests for camel brucellosis and wildlife. Strategies for the implementation of animal vaccination are also discussed.

Brucellosis Seropositivity in Animals and Humans in Ethiopia: A Meta-analysis

BACKGROUND

The objectives of this study were to assess the heterogeneities of estimates and to estimate the seroprevalence of brucellosis in animals and humans in Ethiopia.

METHODS/PRINCIPAL FINDINGS

Data from 70 studies covering 75879 animals and 2223 humans were extracted. Rose Bengal Plate Test (RBPT) and Complement Fixation Test (CFT) in series were the most frequently used serological tests. A random effects model was used to calculate pooled prevalence estimates. The overall True Prevalence of brucellosis seropositivity in goats and sheep were estimated at 5.3% (95%CI = 3.5, 7.5) and 2.7% (95%CI = 1.8, 3.4), respectively, and 2.9% for each of camels and cattle. The prevalence was higher in post-pubertal than in pre-pubertal animals (OR = 3.1, 95% CI = 2.6, 3.7) and in the pastoral than in the mixed crop-livestock production system (OR = 2.8, 95%CI = 2.5, 3.2). The incidence rates of brucellosis in humans of pastoral and sedentary system origins were estimated at 160 and 28 per 100 000 person years, respectively.

CONCLUSIONS

The seroprevalence of brucellosis is higher in goats than in other species. Its occurrence is evocative of its importance in the country in general and in the pastoral system in particular. Public awareness creation could reduce the transmission of Brucella spp. from animals to humans and the potential of livestock vaccination as a means of control of brucellosis needs to be assessed.

Seroprevalence and comparison of different serological tests for brucellosis detection in small ruminants

Aim:

The aim was to study the seroprevalence and efficacy of the different serological tests used for detection of antibody against Brucella species in small ruminants of Banaskantha district of North-Gujarat.

Materials and Methods:

Total 1000 serum samples comprising of 485 from sheep and 515 from goat tested for detection of antibodies against the Brucella species by three different serological tests viz., Rose bengal plate test (RBPT), Standard tube agglutination test (STAT), and Indirect Enzyme-linked immunosorbent assay (I-ELISA).

Results:

The seroprevalence of brucellosis in small ruminants was 11.30%, 11.10%, and 8.80% by RBPT, STAT, and I-ELISA, respectively. The seroprevalence of brucellosis was found to be higher in sheep than goats. The sensitivity of RBPT was found slight more than STAT, but the specificity of both tests was same. In this study, the overall agreement of RBPT and STAT with I-ELISA was found 92.50% and 92.30% in small ruminants, respectively.

Conclusion:

I-ELISA was a better serological test as compared to RBPT and STAT in the sense of sensitivity, specificity, and rapidity and it could be advocated for screening of brucellosis in sheep and goats.

Camelus dromedarius brucellosis and its public health associated risks in the Afar National Regional State in northeastern Ethiopia

BACKGROUND

A cross-sectional study was carried out in four districts of the Afar region in Ethiopia to determine the prevalence of brucellosis in camels, and to identify risky practices that would facilitate the transmission of zoonoses to humans. This study involved testing 461 camels and interviewing 120 livestock owners. The modified Rose Bengal plate test (mRBPT) and complement fixation test (CFT) were used as screening and confirmatory tests, respectively. SPSS 16 was used to analyze the overall prevalence and potential risk factors for seropositivity, using a multivariable logistic regression analysis.

RESULTS

In the camel herds tested, 5.4% had antibodies against Brucella species, and the district level seroprevalence ranged from 11.7% to 15.5% in camels. The logistic regression model for camels in a herd size > 20 animals (OR = 2.8; 95% CI: 1.16-6.62) and greater than four years of age (OR = 4.9; 95% CI: 1.45-16.82) showed a higher risk of infection when compared to small herds and those ≤ 4 years old. The questionnaire survey revealed that most respondents did not know about the transmission of zoonotic diseases, and that their practices could potentially facilitate the transmission of zoonotic pathogens.

CONCLUSIONS

The results of this study revealed that camel brucellosis is prevalent in the study areas. Therefore, there is a need for implementing control measures and increasing public awareness in the prevention methods of brucellosis.

Seroprevalence of Brucellosis and Q-Fever in Southeast Ethiopian Pastoral Livestock

To assess seroprevalences of Brucella and C. burnetii in pastoral livestock in southeast Ethiopia, a cross-sectional study was carried out in three livestock species (cattle, camels and goats). The study was conducted from July 2008 to August 2010, and eight pastoral associations (PAs) from the selected districts were included in the study. Sera from a total of 1830 animals, comprising 862 cattle, 458 camels and 510 goats were screened initially with Rose Bengal plate test (RBPT) for Brucella. All RBPT positive and 25% of randomly selected negative sera were further tested by ELISA. These comprise a total of 460 animals (211 cattle, 102 camels and 147 goats). Out of sera from total of 1830 animals, 20% were randomly selected (180 cattle, 90 camels and 98 goats) and tested for C. burnetii using ELISA. The seroprevalences of Brucella was 1.4% (95% confidence interval (CI), 0.8-2.6), 0.9% (95% CI, 0.3-2.7)b and 9.6% (95% CI, 5.2-17.1) in cattle, camels and goats, respectively. Goats and older animals were at higher risk of infection (OR=7.3, 95% CI, 2.8-19.1) and (OR=1.7 95% CI, 0.9-2.9), respectively. Out of 98 RBPT negative camel sera, 12.0% were positive for ELISA. The seroprevalences of C. burnetii were 31.6% (95% CI, 24.7-39.5), 90.0% (95% CI, 81.8-94.7) and 54.2% (95% CI, 46.1-62.1) in cattle, camels and goats, respectively. We found positive animals for C. burnetii test in all tested PAs for all animal species. Being camel and older animal was a risk factor for infection (OR=19.0, 95% CI, 8.9-41.2) and (OR=3.6, 95% CI, 2.0-6.6), respectively. High seropositivity of C. burnetii in all livestock species tested and higher seropositive in goats for Brucella, implies risks of human infection by both diseases. Thus, merit necessity of further study of both diseases in animals and humans in the area.

A study on seroprevalence of caprine brucellosis under three livestock production systems in southern and central Ethiopia

Caprine brucellosis in Ethiopia is less commonly reported with limited information on the disease status in the country. The objective of this study was therefore to highlight the status of goat brucellosis in three distinctly different livestock production systems of southern and central Ethiopia. A total 3,315 goats of different age and sex, living with other animals in variable flock size, were sampled from 448 flocks raised in sedentary, pastoral and agro-pastoral production systems. Goats were bled aseptically and sera were collected for serial testing using Rose Bengal Plate Test as screening test and subsequently complement fixation test as confirmatory test. Questionnaire and laboratory data were analysed for descriptive, univariable and multivariable logistic regression analysis both at individual and flock level (STATA 11). The study revealed an overall animal level seroprevalence of 1.9 % (95 % CI 1.5, 2.4). In sedentary production system, the observed seroprevalence was 0.6 % (95 % CI 0.2, 0.9) while 1.9 % (95 % CI 1.1, 2.7) and 7.6 % (95 % CI 5.1, 10.1) were the proportion of seroreactors for agro-pastoral and pastoral production systems, respectively. The observed prevalence difference between the three production systems was statistically significant (P < 0.05). At the flock level analysis, 11.2 % (95 % CI 8.2, 14.1) of the flocks sampled had at least one seropositive goat among themselves. Like individual level analysis, the highest prevalence of 32.5 % (95 % CI 21.9, 43.0) was recorded for pastoral production system, followed by agro-pastoral, 13.0 % (95 % CI 7.0, 19.0) and sedentary production system, 3.6 % (95% CI 1.3, 6.0). Accordingly, the odds of Brucella seropositivity were higher (OR = 12.8) in pastoral followed by agro-pastoral (OR = 4.0) in relation to sedentary production system. Large numbers of seroreactors were observed in adult age living in larger flocks with other livestock species. However, no difference was noted between male and female goats. Finally, the need for nationwide survey and subsequent designing and implementation of appropriate control measure is suggested.

Seroepidemiological study of livestock brucellosis in a pastoral region

A seroepidemiological study of Brucella infections in multiple livestock species in the Borana pastoral system of Ethiopia was performed between December 2007 and October 2008. A cross-sectional multi-stage sampling technique was employed to select 575 cattle, 1073 camels and 1248 goats from the target populations. Sera were collected from the animals, and serially tested using Rose Bengal test and complement fixation test. Overall prevalence and prevalence with respect to explanatory variables were established, and potential risk factors for seropositivity were analysed using a multivariable logistic regression. The results showed that 8·0% (95% CI 6·0–10·6), 1·8% (95% CI 1·1–2·8) and 1·6% (95% CI 1·0–2·5) of the tested cattle, camels and goats, respectively, had antibodies to Brucella antigen. Positive reactors were found in 93·8% of the villages with more frequent detection of positive cattle (93·3%) than camels (56·3%) and goats (37·5%). Risk factors identified for cattle were: keeping more livestock species at household level (OR 4·1, 95% CI 1·9–8·9), increasing age of the animal (OR 2·8, 95% CI 1·3–6·0) and wet season (OR 3·3, 95% CI 1·6–6·9). Increase in household-level species composition (OR 4·1, 95% CI 1·2–14·2) and wet season (OR 3·7, 95% CI 1·5–9·1) were found to be risk factors for seropositivity in camels and goats, respectively. Existence of more than one seroreactor animal species in most villages and association of increased livestock species composition with seropositivity may add more credence to the possibility of cross-species transmission of Brucella infections. Although no attempt to isolate Brucella spp. was made, our results suggest that cattle are more likely maintenance hosts of Brucella abortus which has spread to goats and camels. This should be substantiated by further isolation and identification of Brucella organisms to trace the source of infection and transmission dynamics in various hosts kept under mixed conditions. In conclusion, the present study suggests the need for investigating a feasible control intervention and raising public awareness on prevention methods of human exposure to brucellosis.

Seroprevalence of brucellosis and its contribution to abortion in cattle, camel, and goat kept under pastoral management in Borana, Ethiopia

The involvement of Brucella infection in causing abortion was investigated in a breeding female subpopulation of 283 cattle, 756 camels, and 757 goats. Serum samples were serially tested using the Rose Bengal test and complement fixation test. The study showed that anti-Brucella antibodies were prevalent in 10.6% (95% confidence interval (CI), 7.4, 14.9), 2.2% (95%CI, 1.4, 3.7), and 1.9% (95%CI, 1.1, 3.2) of cattle, camel, and goats, respectively. Abortion was more commonly reported in camels (23.4%) than cattle (13.8%) and goats (12.4%). The results of this study suggested that Brucella infections contribute significantly to abortion in cattle (odds ratio (OR), = 4.7; 95%CI, 2.0, 10.8) and goats (OR = 6.9; 95%CI, 2.2, 21.7) but not in camels. The number of young animals produced by breeding females seems to be apparently reduced in seropositive groups. Keeping more than two animal species at household level was found to be the risk factor for cattle (OR = 3.1; 95%CI, 1.2, 7.9) and camel (OR = 5.3; 95%CI, 1.2-23.5) seropositivity to Brucella infection when compared to those animals from households that keep only two animal species. This may suggest a possibility of cross species transmission of Brucella infection under such mixed herding. Wet season (OR = 4.8; 95%CI, 1.3, 18.1) was found to be associated with seropositivity in goats, linked to a coincidence of increased deliveries in flocks with possible excretion of Brucella organisms. The study results suggest that Brucella infection is the likely cause of abortion in cattle and goats while other causes largely outweigh brucellosis as a cause of abortion in camels in Borana, hence, contributing to reproductive loss.