Serological survey of bovine brucellosis in Fulani nomadic cattle breeds (Bos indicus) of North-central Nigeria: Potential risk factors and zoonotic implications

Brucellae as resilient intracellular pathogens: epidemiology, host-pathogen interaction, recent genomics and proteomics approaches, and future perspectives

Brucellosis is considered one of the most hazardous zoonotic diseases all over the world. It causes formidable economic losses in developed and developing countries. Despite the significant attempts to get rid of Brucella pathogens in many parts of the world, the disease continues to spread widely. Recently, many attempts proved to be effective for the prevention and control of highly contagious bovine brucellosis, which could be followed by others to achieve a prosperous future without rampant Brucella pathogens. In this study, the updated view for worldwide Brucella distribution, possible predisposing factors for emerging Brucella pathogens, immune response and different types of Brucella vaccines, genomics and proteomics approaches incorporated recently in the field of brucellosis, and future perspectives for prevention and control of bovine brucellosis have been discussed comprehensively. So, the current study will be used as a guide for researchers in planning their future work, which will pave the way for a new world without these highly contagious pathogens that have been infecting and threatening the health of humans and terrestrial animals.

Herd and animal level seroprevalence and associated risk factors of bovine brucellosis in different agro-ecologies of southwest Ethiopia

Brucellosis is a zoonotic infection that commonly affects cattle in Ethiopia, causing significant negative economic impact. A cross-sectional study was carried out between November 2020 and November 2021 in southwest Ethiopia to determine the seroprevalence of brucellosis and its associated risk factors in cattle herds. Blood samples were taken from 461 randomly selected cattle to test for the presence of Brucella antibodies using the Rose Bengal Plate test, with positive serum confirmed through the complement fixation test. A multivariable random effect logistic regression analysis was used to identify potential risk factors for Brucella seropositivity. The study found 7.14% (95% CI: 4.44-9.01) seroprevalence at the animal level and 12.23% (95% CI: 6.52-16.05) at the herd level based on the complement fixation test. Age (OR = 6.9, 95%CI: 1.83-15.97), herd size (OR = 3.66, 95%CI: 1.39-9.61), introducing new animals (OR = 2.72, 95%CI: 1.17-6.29), management system (OR = 12.2, 95%CI: 1.53-26.80), species composition (OR = 4.24, 95%CI: 1.51-11.91), and abortion (OR = 7.1, 95%CI: 1.93-15.39) were found to be associated with Brucella seropositivity. The analysis also revealed two risk factors for Brucella infection at the herd level, including herd size (OR = 3.4, 95% CI: 1.05-10.68) and species composition (OR = 3.1, 95% CI: 1.20-7.88). The presence of Brucella antibodies in cattle highlights the need for increased awareness and measures to mitigate the identified risk factors of the disease to prevent its spread. Furthermore, further studies are necessary to investigate the zoonotic transmission of brucellosis to humans and its role in cattle reproduction disorders in the study area.

Neglected zoonotic bacteria causes and associated risk factors of cattle abortion in different agro-ecological zones of southwest Ethiopia

Three zoonotic bacteria, Coxiella burnetii, Leptospira spp, and Brucella spp, cause cattle abortion and significant losses in the livestock sector. However, these infections were neglected diseases in Ethiopia. Between October 2020 and October 2021, a cross-sectional study was carried out in southwest Ethiopia to determine the prevalence of abortion and identify the major zoonotic bacterial causes and risk factors that contribute to abortion. Using an indirect ELISA, antibodies to Brucella abortus, Leptospira Hardjo, and Coxiella burnetii were detected in serum samples taken from 461 cattle. Potential risk factors for cattle abortion were found using a multivariable random effect logistic regression analysis. The prevalence of cattle abortion was found to be 22.56 % (95 % CI: 18.74-26.38) in the study areas. Leptospira Hardjo (OR=1.8, 95% CI: 1.04-3.00), Coxiella burnetii (OR=2.7, 95 % CI: 1.26-5.62), and Brucella abortus (OR=9.8, 95 % CI: 1.27-17.15) were all associated with the occurrence of abortion in cattle, as were their co-infections (OR=8.1, 95 % CI: 1.28-39.33). Other risk factors for cattle abortion included breed (OR=16.7, 95 % CI: 2.20-26.77), herd size (OR=2.5, 95 % CI: 1.16-4.68), breeding method (OR=2.3, 95 % CI: 1.33-3.90), and contact with dogs (OR=2.2, 95 % CI: 1.34-3.53). According to the findings of this study, Brucella abortus, Coxiella burnetii, and Leptospira Hardjo are serious zoonoses that cause significant production loss in cattle due to abortion. To prevent transmission of these zoonotic diseases, it is crucial to implement effective control measures and increase public awareness. The causes of cattle abortion in the study areas should also be isolated and characterized.

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.

Sero-prevalence and risk factors of Brucella presence in farm bulk milk from open and zero grazing cattle production systems in Rwanda

BACKGROUND

Animal and human brucelloses have been reported in Rwanda, human brucellosis being linked to drinking inadequately heat-treated milk. However, information on Brucella detection and prevalence in milk produced in Rwanda is limited.

OBJECTIVES

To determine the sero-prevalence and risk factors of Brucella in farm bulk milk from zero and open grazing cattle production systems in Rwanda.

METHODS

A total of 330 farm bulk milk samples were collected from 198 zero grazing farms and 132 open grazing farms in a cross-sectional study in Rwanda. Sero-prevalence of Brucella in milk was analysed using indirect enzyme-linked immunosorbent assay. A questionnaire was administered to farmers to determine the risk factors of milk contamination with Brucella.

RESULTS

Anti-Brucella antibodies were prevalent in 19.7% (95% confidence interval (CI), 15.5-24.4) of the 330 collected farm bulk milk. Sero-prevalence was significantly higher (p < 0.05) in open grazing farms (37.9% [50/132]) than in zero grazing farms (7.6% [15/198]). Practising open grazing system (odds ratio, OR = 69.5; 95% CI = 1.6-3033.6), history of abortion (OR = 19.5; 95% CI = 8.1-46.8) and placenta retention (OR = 4.2; 95% CI = 1.7-10.3) were the significant risk factors for the presence of anti-Brucella antibodies in milk.

CONCLUSION

Notably, more than a third of farm bulk milk from open grazing farms in Rwanda contains Brucella antibodies. Considering the zoonotic nature of Brucella, there is a need to reinforce brucellosis control programs in the country.

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.

Seroprevalence and risk factors of brucellosis and the brucellosis model at the individual level of dairy cattle in the West Bandung District, Indonesia

Background and Aim

Brucellosis is a zoonotic bacterial infectious disease. West Bandung is a center for dairy farming in West Java Province District and endemic for brucellosis. The aim of the study was to determine the prevalence, the associated risk factors, and the brucellosis model at the individual level of dairy cattle in the West Bandung District.

Materials and Methods

The research was conducted through a cross-sectional study. The samples were collected from the serum blood of dairy cattle. Data obtained from the questionnaire were used to investigate risk factors. Multistage random sampling was applied as the sampling technique; therefore, a sample size of 540 cows was selected. The number of farms and cattle on each farm was calculated using a variant effect design of the farm as well as 108 farms was selected with five cattle samples per farm. The results in regard of the research sample acquisition in the West Bandung District included 588 dairy cows from 116 farms, exceeds the number of samples calculated (540 dairy cows and 108 farms). The rose Bengal test (RBT) and the complement fixation test (CFT) were performed for brucellosis testing. Data associated with brucellosis cases at the individual level of the dairy cattle were analyzed using descriptive statistics univariate, bivariate with Chi-square, and odds ratio (OR). Moreover, multivariate logistic regression was used for the analysis during modeling.

Results

The results showed that the prevalence of brucellosis at the individual level in the West Bandung District was 5.10%. Risk factors associated with brucellosis in cattle included the history of abortion (p=0.000; OR=9.9), the history of placental retention (p=0.000; OR=6.6), the history of endometritis (p=0.000; OR=5.5), the history of stillbirth (p=0.043; OR=3.0), the history of pregnancy abortion age at 7-8 months (p=0.000; OR=15.2), and the history of pregnancy abortion at the age of 4-6 months (p=0.007; OR=3.8). The model of brucellosis in dairy cows was the following: = -3.2843+3.41033 the history of pregnancy abortion at the age of 7-8 months +2.54503 the history of pregnancy abortion at the age of 4-6 months +1.86185 age of cattle >2 years - 1.0469 Calving interval 12 months. The model showed the factors that were associated with brucellosis at the individual level of dairy cattle included the history of pregnancy abortion at the age of 7-8 months (β=+3.41033; OR=30.3), the history of pregnancy abortion at the age of 4-6 months (β=+2.54503; OR=12.7); age of cattle >2 years (β=+1.86185; OR=1.2), and Calving interval ≤12 months (β=-1.04691; OR=0.34).

Conclusion

The results of this research showed that the prevalence of brucellosis at the individual level of dairy cattle in the West Bandung district was 5.10%. The risk factors could contribute to the increase of the brucellosis cases, that is, the history of pregnancy abortion at the age of 7-8, the history of pregnancy abortion at the age of 4-6 months, and the age of cattle >2 years. The risk factors can be decreased in the brucellosis cases, that is, calving intervals ≤12 months.

A retrospective sero-epidemiological survey of bovine brucellosis on commercial and communal farming systems in Namibia from 2004 to 2018

Cattle production is the major livestock production activity and the mainstay of Namibia's economy. Sustained beef exports are contingent on a sound sanitary environment where diseases such as brucellosis are under control. In this retrospective study, 49,718 bovine brucellosis testing results from 2004 to 2018 were analyzed to determine the proportion of sero-positive cattle and herds, and the spatial distribution of positive reactors from commercial and communal areas. In total, 244 positive reactors were identified based on the Rose Bengal Test (RBT) and the Complement Fixation Test (CFT) in series, giving an overall proportion of infected animals of 0.49% (244/49,718; 95% CI, 0.43-0.56%) and an overall proportion of infected herds of 9.26% (78/842; 95% CI, 7.49-11.41%). There was a higher proportion of sero-positive communal herds (33.09%) and cattle (10.27%) than commercial herds (4.67%) and cattle (0.24%; p < 0.05). Annually, the proportion of positive reactors was 0-1.37% in the commercial area and 0-52.38% in the communal areas, with a clear decline in positive reactors in the communal areas. Within the commercial sector, the proportion of positive reactor dairy, beef, and export cattle was 0.19% (51/27,067; 95% CI, 0.14-0.25%), 0.30% (48/16,098; 95% CI, 0.22-0.40%), and 0.33% (16/4811; 95% CI, 0.20-0.54%), respectively. Abortions were found to be the major reason for Brucella testing in the communal areas. About 12.65% (96/759) of abortion-linked sera tested positive in the communal areas, but none were positive in beef or dairy cattle. Widespread vaccination of cattle and robust planned surveillance is recommended to reduce the incidence of the disease, its associated production losses and public health risk.

Zoonotic Pathogen Seroprevalence in Cattle in a Wildlife-Livestock Interface, Kenya

A cross-sectional study was conducted to determine the seroprevalence of Brucella spp. and Leptospira spp. and risk factors of exposure in cattle in three zones with varying land use types and wildlife-livestock interactions. Five villages were selected purposively; two in areas with intensive livestock-wildlife interactions (zone 1), another two in areas with moderate livestock-wildlife interactions (zone 2) and one in areas where wildlife-livestock interactions are rarer (zone 3). Sera samples were collected from 1170 cattle belonging to 390 herds in all the zones and tested for antibodies against Brucella abortus and Leptospira interrogans serovar hardjo using ELISA kits. Data on putative risk factors for seropositivity of these pathogens in cattle were collected using a questionnaire. The overall apparent animal-level seroprevalence of brucellosis and leptospirosis was, respectively, 36.9% (95% CI 34.1-39.8) and 23.5% (95% CI 21.1-26.0). Brucella spp. seroprevalence was higher in zone 1 than in zones 2 and 3 (χ2 = 25.1, df = 2, P < 0.001). Zones 1 and 2 had significantly higher Leptospira spp. seroprevalence than zone 3 (χ2 = 7.0, df = 2, P = 0.029). Results of multivariable analyses identified animal sex (female) and zones (high interface area) as significant predictors (P < 0.05) of animal-level seropositivity of Brucella spp. For Leptospira spp., important predictors of animal-level seropositivity were animal sex (female), zones (moderate interface area) and herds utilizing a communal grazing reserve. The seroprevalences of Brucella spp. and Leptospira spp. in cattle were higher in areas with moderate to high wildlife-livestock interactions than those with rare interactions.

Serological and histopathological investigation of brucellosis in cattle in Medea region, Northern Algeria

AIM

This study was performed to determine the prevalence of bovine brucellosis in Medea region, Northern Algeria.

MATERIALS AND METHODS

The study was carried out on 495 non-vaccinated cattle, of which 280 (30 males and 250 females) belonged to 57 cattle farms and 215 cows were sampled at abattoirs of Medea. Sera collected from the cattle were tested using the Rose Bengal test and confirmed by histopathological analysis.

RESULTS

Serological examination revealed that 7/57 farms (12.28%) were infected, of which 7/280 (2.5%) cattle were seropositive. The prevalence in females and males was 2.4% (6/250) and 3.33% (1/30), respectively. No significant difference has been observed between females and males. Older animals (≥8 years) were infected more. The prevalence of infection was 9.1%. Seroprevalence of Brucella infection in cows that have already had abortion was higher compared with non-aborted cows (4.34% and 2.20%, respectively). In abattoirs, a total of 25 (11.62%) seropositive cows were detected, and the histopathological analysis was positive in all these cows.

CONCLUSION

The study indicates that brucellosis indeed exists in cattle in Medea and shows that the meat of slaughtered cattle tested positive for brucellosis may constitute a real risk of transmission to both butchery personnel and consumers, which requires that the meat of infected animals should be analyzed before being marketed.

Risk factors for new bovine brucellosis infections in Colombian herds

BACKGROUND

Bovine brucellosis is a zoonotic disease that causes substantial economic losses and has a strong impact on public health. The main objective of this paper is to determine the risk factors for new infections of Brucella abortus on Colombian cattle farms previously certified as being free of brucellosis. A case-control study was conducted by comparing 98 cases (farms certified as brucellosis-free for three or more years but became infected) with 93 controls (farms that remained brucellosis-free during at least the previous three years). The farms were matched by herd size and geographical location (municipality). Information was obtained via a questionnaire completed by veterinary officers through a personal interview with the herd owners.

RESULTS

Two-thirds of the herds (67%) were dairy herds, 16% were beef herds, and 17% were dual-purpose (beef and milk) herds. After exploratory univariate analysis, all explanatory variables with a p-value of ≤0.20 were included in a logistic regression model using the forward stepwise method to select the model with the best goodness of fit. The significant risk factors were the replacement of animals from farms not certified as brucellosis-free compared to replacement from certified brucellosis-free farms (OR = 4.84, p-value < 0.001) and beef cattle farms compared to dairy cattle farms (OR = 3.61, p-value = 0.017). When herds with and without artificial insemination were compared, it was observed that farms that used natural breeding with bulls from non-certified herds had a higher risk than farms using artificial insemination (OR = 2.45, p-value = 0.037), but when the bulls came from brucellosis-free farms, farms with natural breeding were less affected (OR = 0.30, p-value = 0.004) than farms using artificial insemination, whether with frozen semen from certified brucellosis-free herds or fresh semen from uncontrolled herds. The latter is commonly sold to neighbouring farms.

CONCLUSIONS

The government should make efforts to inform farmers about the risks involved in the introduction of semen and replacement heifers from farms that are not certified as brucellosis-free and to establish measures to control these practices.

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.

Prevalence and risk factors for brucellosis seropositivity in cattle in Nyagatare District, Eastern Province, Rwanda

A survey involving 120 small-scale dairy farmers was carried out to assess risk factors associated with brucellosis in cattle from selected sectors of Nyagatare District, Rwanda. A sample of cattle from nine selected sectors of Nyagatare was tested for brucellosis using the Rose Bengal Test. Of the respondents, 57.5% were unaware of brucellosis as a disease, 85.8% did not screen new additions to the herd for brucellosis and 82.5% did not remove brucellosis seropositive animals from the herd. The prevalence of brucellosis in herds with cows with no history of abortion was 38.5% and 17.0% in those with a history of abortion. None of the respondents disinfected abortion sites or vaccinated against brucellosis. The prevalence of brucellosis in cows with a history of retained placenta was 36% and 2% in those with no history of retained placenta. Of the respondents, 62.5% reportedly fed foetal membranes to dogs. About 65.8% of the respondents with brucellosis-positive animals reported a calving interval longer than 1 year. Katabagemu (28.6%) had the highest prevalence of brucellosis seropositivity while Karama had none. Brucellosis in cows (21.4%) was significantly higher than that in heifers (12.8%) (p < 0.05), but there was no significant difference between heifers and bulls or between bulls and cows (p > 0.05). The occurrence of brucellosis in herds with 40-70 cattle (26.9%) was significantly greater than the 14.9% of herds with 10-39 cattle (p < 0.05). Seropositivity to brucellosis in cross-breed cattle (23.6%) was significantly greater than that in indigenous cattle (13.8%) (p < 0.05). There was no significant difference in the overall prevalence of brucellosis in cattle from different grazing systems (p > 0.05). Seropositivity to brucellosis was significantly different (p < 0.05) between the fourth parity (32.5%) and first parity (14.3%) cows. The findings in this study confirmed the existence of brucellosis as a problem in Nyagatare and the authors recommend that farmer education on the epidemiology, risk factors and mitigation of the disease be undertaken as a matter of urgency.

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.