Epidemiological study of bovine brucellosis in three senatorial zones of Bauchi State, Nigeria

Seroprevalence and Risk Factors Related to Bovine Brucellosis in Continental Ecuador

Bovine brucellosis is a worldwide zoonotic contagious disease. According to World Animal Health Information System reports Ecuador has presented an increasing number of bovine brucellosis outbreaks in the continental territory over the past years (756 in 2018 versus 964 in 2021), generating economic losses for producers and causing a risk to public health. A cross-sectional study was conducted to investigate the seroprevalence of bovine brucellosis and associated risk or protective factors between May and June 2018. This stratified random study was implemented in 290 cattle herds located in the 23 provinces of continental Ecuador, which represents a total of 3737 cows aged 24 months or older. A competitive ELISA was used to detect Brucella antibodies. Simultaneously, an epidemiological survey was implemented to assess the brucellosis risk or protective factors. The apparent prevalence of bovine brucellosis at the herd level was 21.3% (95% CI: 16.8-26.6) and 6.2% (95% CI: 5.5-7) at the animal level. Univariate and multivariate logistic regression analyses were performed to determine the relationship between the potential factors associated with the presence of bovine brucellosis. The risk factors identified after multivariate analysis were a surface in ha per herd > 70 ha (OR = 2.73; 95% CI: 1.18-6.32) and the number of parturitions per animal (two or more with OR ≥ 1.8 and p-value ≤ 0.047). On the contrary, the protective factors were the region (farms located in the eastern region) and the absence of reported clinical signs. In addition, in herds where extensive production predominates, farmers have a low level of knowledge, and the farm biosecurity level is low. These results can guide the authorities in managing the risk factors identified, understanding the current epidemiological situation in Ecuador, improving the bovine brucellosis control program and food safety, as well as increase the one-health approach.

Evaluation of serological diagnostic tests for bovine brucellosis in dairy cattle herds in an endemic area: a multicenter study

Brucellosis is known as one of the most common zoonotic diseases worldwide affecting both livestock and humans. It causes abortions, reduces milk production, and infertility in infected animals. The disease is routinely diagnosed through three serological techniques, such as rose bengal plate test (RBPT), standard agglutination test (SAT), and indirect enzyme-linked immunosorbent assay (I-ELISA). The aim of this study was to identify and compare the brucellosis seroprevalence among dairy cattle farms through these different serological tests. From 2112 sampled dairy cattle in different parts of Iran, RBPT, SAT, and I-ELISA led to 296 (14.02%), 215 (10.18%), and 297 (14.06%) positive results, respectively. Brucella abortus biovar 3 (62 cases) was identified as the most common cause of brucellosis in tested animals. Our results showed that the specificity and sensitivity of I-ELISA were higher than those obtained by RBPT and SAT. In this study, the overall agreement of RBPT and SAT with I-ELISA reached 95.21% and 94.12% in dairy cattle farms, respectively. Furthermore, Cohen's kappa statistical analysis revealed that the best degree of agreement was seen between RBPT and I-ELISA (0.80), followed by RBPT and SAT (0.78) and finally SAT and I-ELISA (0.72), thereby indicating a strong agreement between RBPT and I-ELISA methods and good agreement between SAT and I-ELISA methods. The McNemar analysis also showed that a significant difference exists between positive and negative results determined by SAT and I-ELISA methods (p < 0.0001). However, the positive and negative results determined by I-ELISA and RBPT did not show a significant difference (p = 0.9207). Therefore, I-ELISA was a more specific and sensitive serological test when compared to RBPT and SAT and could remarkably decrease non-specific reaction by improving the serological screening specificity for an accurate brucellosis diagnosis in endemic areas.

Human and Animal Brucellosis in Nigeria: A Systemic Review and Meta-Analysis in the Last Twenty-One Years (2001–2021)

Simple Summary

Brucellosis caused by Brucella spp. is transmitted by direct or indirect contact with infected animals or their secretions and through the consumption of infected animal meat and unpasteurized milk/milk products. Brucellosis is classified as one of the top neglected zoonosis by the World Health Organization (WHO), and despite this, it does not attract the appropriate attention it requires from both the Federal and State ministries of health in Nigeria. Currently, there is a lack of coordinated national data on the prevalence and distribution of human and animal brucellosis. Thus, published research works between 2001 and 2021 were studied based on set criteria to estimate the burden and distribution of brucellosis in Nigeria. The results of the national seroprevalence of human and animal brucellosis were 17.6% (554/3144) and 13.3% (8547/64,435), respectively. Specifically, 15.8% (7178/45,363) seroprevalence of brucellosis was recorded in northern Nigeria as against 8.7% (1902/21,740) in the southern part. Brucella abortus, B. melitensis, B. suis, and B. canis were reported in 27 of the 36 states. Improved sanitation at the abattoirs, use of personal protective equipment by animal handlers, vaccination of animals against brucellosis, and ranching of animals to curb the spread of the disease should be paramount to all stakeholders.

Abstract

The global burden of human and animal brucellosis remains enormous. The disease, which is endemic in Nigeria, lacks appropriate attention and national data. This review estimated the burden and distribution of human and animal brucellosis in Nigeria in the last twenty-one years (2001–2021). Publications reporting the detection of brucellosis in Nigeria were sorted from different search engines, including PubMed, ResearchGate, Scopus, and Google Scholar, to generate data on its prevalence, spatial distribution, and predisposing factors. The results of the national seroprevalence of human and animal brucellosis as revealed in this study were 17.6% (554/3144) and 13.3% (8547/64,435), respectively. Specifically, 15.8% (7178/45,363) seroprevalence of brucellosis was recorded in northern Nigeria as against 8.7% (1902/21,740) seroprevalence in the southern part. It also indicated that 78.7% of the detected brucellae were un-typed. The Brucella species detected were B. abortus (15.2%), B. melitensis (4%), B. suis (1.8%), and B. canis (0.4%). This study revealed that brucellosis is endemic in Nigeria. Culture and molecular methods for detecting brucellosis and reports on antimicrobial susceptibility testing remain a conjecture. This review will help researchers redirect their research focus and serve as a guide for policymakers on measures for managing brucellosis in Nigeria.

Bayesian Estimation of the Prevalence and Test Characteristics (Sensitivity and Specificity) of Two Serological Tests (RB and SAT-EDTA) for the Diagnosis of Bovine Brucellosis in Small and Medium Cattle Holders in Ecuador

In Ecuador, a national program for bovine brucellosis control has been in implementation since 2008. Given the costs, small- and medium-sized livestock holders are not completely committed to it. The objective of this study was to determine true prevalence (TP) of bovine brucellosis in small- and medium-sized herd populations, as well as the diagnostic sensitivity and specificity of the Rose Bengal (RB) test and the sero-agglutination test (SAT)-EDTA using a Bayesian approach. Between 2011 and 2016, 2733 cattle herds were visited, and 22,592 animal blood samples were taken in nineteen provinces on mainland Ecuador. Bayes-p and deviance information criterion (DIC) statistics were used to select models. Additionally, risk-factor analysis was used for herds according to their brucellosis test status. True prevalence (TP) in herds was estimated by pool testing. National seroprevalence of farms was 7.9% (95% CI: 6.79–9.03), and TP was 12.2% (95% CI: 7.8–17.9). Apparent prevalence (AP) in animals was 2.2% (95% CI: 1.82–2.67), and TP was 1.6% (95% CrI: 1.0–2.4). Similarly, the sensitivity of the RB was estimated at 64.6% (95% CrI: 42.6–85.3) and specificity at 98.9% (95% CrI: 98.6–99.0); for the SAT-EDTA test, sensitivity was 62.3% (95% CrI: 40.0–84.8) and 98.9% (95% CrI: 98.6–99.1) for specificity. Results of the two tests were highly correlated in infected and uninfected animals. Likewise, high spatial variation was observed, with the Coastal Region being the zone with the highest TP at 2.5%. (95% CrI: 1.3–3.8%) in individual animals and 28.2% (95% CI: 15.7–39.8) in herds. Risk factors include herd size, type of production (milk, beef, and mixed), abortions recorded, and vaccination. The results of this study serve to guide authorities to make decisions based on parallel testing at the beginning of a bovine brucellosis program for small livestock holders to increase sensitivity level of the screening tests in Ecuador.

Socio-economic impacts of brucellosis on livestock production and reproduction performance in Koibatek and Marigat regions, Baringo County, Kenya

Background

Brucellosis in Africa is caused by Brucella species transmitted through contaminated or contacts with infected animals or their carcasses. The disease reduces livestock production and reproduction performance evident by frequent episodes of abortion, still births, swollen testes, weak calves/lambs and swollen joints. However, the socio-economic impacts of these brucellosis-associated symptoms on milk, fat, meat and blood production, infertility, sale value, dowry and costs of treatment has not been evaluated extensively in developing countries. In Baringo County, Kenya, there is a continuous movement of cattle as a result of trade and grazing, which predisposes many herds to brucellosis infection. The objective of this study was to investigate the socio-economic impacts of Brucella infection on production systems for sheep, goats, cattle and camels and explore the impact of brucellosis on livestock production and reproduction performance among livestock keeping communities in Baringo County, Kenya. The study adopted a cross-sectional survey using quantitative data collection methods.

Results

Results demonstrated an impact on milk production in suspected brucellosis cases resulting from abortions (OR = 0.151, P < 0.0001) and swollen joints (OR = 2.881, P < 0.0001). In terms of infertility, abortion as a symptom of brucellosis (OR = 0.440, P = 0.002), still birth (OR = 0.628, P = 0.042), and weak calf or lamb (OR = 0.525, P = 0.005) had an impact on infertility. In terms of sale value, abortion (OR = 0.385, P = 0.008), weak calf/lamb (OR = 2.963, P = 0.013) had an impact on sale value. Other analyses demonstrated that for dowry, swollen testes (OR = 5.351, P = 0.032), weak calf and lambs (OR = 0.364, P = 0.019) had a likelihood of reduction of dowry value. Finally, in terms of cost of treatment, abortion (OR = 0.449, P = 0.001), still births (OR = 0.208, P = 0.015), swollen testes (OR = 0.78, P = 0.014), weak calf/lambs (OR = 0.178, P = 0.007) and swollen joints (OR = 0.217, P = 0.003) significantly increased the costs of treatments. There was no impact on fat and meat and blood production.

Conclusion

Even though there was a huge socio-economic impact on milk production, infertility, sale value, and dowry, it was the costs of treatment that was significantly impacted on all symptoms associated with brucellosis on this community. A ‘One Health’ approach in tackling the brucellosis menace as a holistic approach is recommended for both humans and their livestock.

Seroprevalence of brucellosis and associated risk factors among abattoir workers in Bauchi State, Nigeria

Introduction

Brucellosis is a reemerging and neglected zoonotic disease. It is an occupational bio-hazard and a public health problem. The objective of the study was to determine the seroprevalence of brucellosis and its risk factors among abattoir workers in Bauchi state.

Methods

A cross-sectional study was conducted in the three senatorial district abattoirs of Bauchi State. Abattoir workers (n=284) were selected by stratified random sampling. Data were collected using an adapted questionnaire. Serum samples collected, were screened for brucellosis with Rose Bengal Plate Test (RBPT), tested with Enzyme Linked Immunosorbent Assay (ELISA). Seropositive participants were positive for both RBPT and ELISA. Data were described in proportions and analyzed using bivariate and multivariate analysis.

Results

Participants were all male, age range: 18-70 years (mean 35 ±13 years). Ninety-five participants were seropositive (seroprevalence 33.5%) after laboratory testing. Following bivariate analysis, using personal protective equipment (PPE) [OR: 0.5 CI95%=0.3>OR: 0.5 CI95%=0.3-0.9] was significantly protective against brucellosis. Slaughtering of animals (OR: 2.19 CI95%= 1.2-3.7), assisting in animal parturition (OR: 2.25 CI95%= 1.3-3.7), working with an open cut/wound (OR:2.1 CI95%= 1.1-3.9) and eating while working in the abattoir [OR:2.4 CI95%= 1.1>OR:2.4 CI95%= 1.1-4.9] were risks of brucellosis. Multivariate analysis showed that slaughtering of animals: Adjusted Odds-Ratio (AOR) = 1.92; CI95% = 1.03 - 3.59) and assisting in animal parturition (AOR = 2.43; CI95% = 1.40 - 4.23) remained significantly associated with brucellosis.

Conclusion

Seroprevalence of brucellosis among abattoir workers in Bauchi state is high. Workers should use PPEs and animal parturitions should be handled by trained personnel alone.

Characterization and evolution of countries affected by bovine brucellosis (1996-2014)

This paper describes the global distribution and temporal evolution of bovine brucellosis due to Brucella abortus during a 19-year period (1996-2014) using the information officially reported to the World Organisation for Animal Health (OIE) by veterinary services of 156 countries. Variables that can influence the health status of bovine brucellosis (i.e., year, per capita Gross Domestic Product (GDP), continent and bovine population) were also analysed. Countries were classified into three categories of health situations: ENZOOTIC: countries infected, which may have been free of brucellosis but for periods of fewer than 3 years; NON-ENZOOTIC: countries where the disease was present but that had at least a 3-year period without the disease; and FREE: countries where the disease remained absent during the whole period. The countries free from bovine brucellosis, or in the process of eradication, were located in Oceania and Europe, while the more affected regions were Central and South America, Africa and parts of Asia. Among the Non-Enzootic countries, the results showed that a very high proportion managed to control the disease during the period of study, with a sharp decline in the percentage of infected countries from 71% in 1996 to 10% in 2014. Among the Enzootic countries, a much smaller proportion managed to control the disease, with a slight drop in the percentage of infected countries from 92% in 1996 to 80% in 2014. A relationship was found between the status of the disease and the availability of economic resources; thus, countries with a high GDP per capita tended to be free from bovine brucellosis. On the other hand, countries with a larger bovine population showed a greater probability to have the disease present. An increase in surveillance programmes and implementation of control policies were observed during the period of study.

Serosurveillance of Brucella antibody in food animals and role of slaughterhouse workers in spread of Brucella infection in Southeast Nigeria

Aim:

The study was carried out to determine the seroprevalence of Brucella antibody in slaughter cattle and goats; and the role of slaughterhouse workers (SHWs) in spread of Brucella infection during slaughterhouse operations in Enugu State, Southeast Nigeria.

Materials and Methods:

Rose Bengal plate test was used to screen for Brucella antibody in 484 cattle and 340 goats slaughtered for human consumption in the state. Structured and pretested questionnaire was used to elicit information from randomly selected SHWs, on socioeconomic characteristics, awareness of brucellosis and involvement in practices that aid dissemination of Brucella infection during slaughterhouse operations.

Results:

Suspected seroprevalence of 2.5% and 4.1% were recorded for Brucella antibody in cattle and goats respectively. There was poor awareness of brucellosis (32.1%) among the workers surveyed. Slaughterhouse practices that aid acquisition or spread of Brucella infection and percentage of SHWs engaged in the practices are: non-use of personal protective clothing during slaughterhouse operations (70.8%), discharge of eviscerated fetuses or pregnant uterine contents by open-air dump method of refuse disposal (64.9%) and illegal sell of eviscerated fetuses or gravid uterine contents for human consumption (59.9%) or preparation of dog food (71.5%).

Conclusion:

The 4.1% suspected seroprevalence of Brucella antibodies in goats represents 128% increase from 1.8% seroprevalence earlier reported in the same species and study area in 2009. Significant amounts of Brucella antibody was detected in the food animals screened. Slaughterhouse workers played significant roles in spread of Brucella infection by their involvement in risk practices and behaviours that facilitate pathogen transmission. Therefore, massive awareness campaign and coordinated brucellosis control program in Enugu State are imperative to forestall the zoonotic and economic consequences associated with brucellosis.

Seroprevalence of brucellosis and Q fever (Coxiellosis) in cattle herds in Maigana and Birnin Gwari agro-ecological zone of Kaduna State, Nigeria

A cross sectional study was conducted to determine the seroprevalence and risk factors of brucellosis and Q fever in cattle in Maigana and Birnin Gwari agro-ecological zone of Kaduna State, Nigeria. This study aimed at determining the significance of Brucella spp. and Coxiella burnetti infections in cattle. A total of 400 sera samples (139 from males and 261 from females cattle) were collected and screened for brucellosis using Rose Bengal Plate test (RBPT) and competitive enzyme linked immunosorbent assay (cELISA) for brucellosis and indirect enzyme-linked immunosorbent assay (iELISA) for Q fever. A structured questionnaire was used to collect data on the sampled animals from the study population. Data were analyzed to determine association and risk factors. Sera analysis revealed that, 18.5 and 6.8% were seropositive by RBPT and cELISA for brucellosis, while 6.2% was seropositive by iELISA for Q fever. A significant association was detected between cattle sex and sensitivity of RBPT for detecting Brucella. Meanwhile, a non-significant association was found between cattle age and breed with sensitivity of RBPT, cELISA, and iELISA. The study indicates that brucellosis and Q ever exist with high prevalence particularly among female cattle. This presents a serious public health problem, calling for greater awareness among stakeholders and for co-ordinated surveillance for the diseases among cattle populations in Nigeria.

Seroprevalence of brucellosis among cattle slaughtered in three municipal abattoirs of Gombe state, Northeastern Nigeria

AIM

A cross-sectional study was conducted to determine the seroprevalence of bovine brucellosis among cattle slaughtered at three municipal abattoirs of Gombe State, Nigeria.

MATERIALS AND METHODS

A total of 200 blood samples collected from slaughtered cattle of different breeds (Sokoto Gudali - 50, White Fulani - 102, Red bororo - 34, and Crossbreeds - 14), sex (males - 19 and females - 181), and from different locations (Billiri - 30, Yamaltu Deba - 50, and Gombe - 120) were screened for brucellosis using rose bengal plate test (RBPT), serum agglutination test (SAT), and microtiter agglutination test (MAT).

RESULTS

Of the 200 serum samples analyzed, 7 (3.5%), 10 (5.0%) and 18 (9.0%) were positive by RBPT, SAT and MAT, respectively. The results showed no statistically significant association between sex and seropositivity to bovine brucellosis. However, seropositivity of bovine brucellosis was higher in females than in males. Similarly, no statistically significant association was observed between breed and occurrence of bovine brucellosis. Moreover, the prevalence of brucellosis was higher in Sokoto Gudali as compared with the other breeds. Based on the study locations, higher seroprevalence was observed in animals screened from Billiri as compared with those from other locations (p<0.05).

CONCLUSION

The presence of Brucella abortus antigen in the sera of slaughtered cattle in Gombe state poses a significant public health risk. Therefore, it is important to carry out further epidemiological studies on fulani herdsmen and cattle herds in the study area, in order to explore the risk factors associated with the occurrence and perpetuation of brucellosis among cattle herds, ascertain the prevalence and status of the disease among both farms and nomadic herds.