Prevalence of antibodies to Brucella species in commercial raw bovine milk in Southwestern Uganda

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.

Importance of brucellosis control programs of livestock on the improvement of one health

Brucellosis not only represents an important health restraint on livestock but also causes high economic losses in many developing countries worldwide. Despite considerable efforts made for the control of brucellosis, the disease is still spreading in many regions (such as the Middle East) where it represents one of the most important health hazards impacting both animals and humans. The present review aims to investigate the efficacy of veterinary control programs regarding brucellosis, with a special focus on current prevention, control, and eradication approaches. The reasons for unsuccessful control programs such as the absence of highly effective vaccines and non-certified bulls are also debated, to understand why the prevalence of brucellosis in livestock is not decreasing in many areas despite considerable efforts taken to date. The importance of governmental and regional investment in brucellosis control remains one of the main limiting factors owing to the limited budget allocated to tackle this disease. In this context, one health concept has generated novel comprehensive approaches with multiple economic implications across the livestock industry and public health. However, the implementation of such global preventive strategies appears to be a key issue for many endemic and low-income countries. According to the collected data, epidemiological contexts including management and trade systems along with well-defined agro-ecological zones should be evaluated in brucellosis endemic countries to improve milk production and to enhance the sustainability of the livestock sector at both national and regional levels.

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.

Bovine brucellosis - a comprehensive review

Brucellosis is a zoonotic disease of great animal welfare and economic implications worldwide known since ancient times. The emergence of brucellosis in new areas as well as transmission of brucellosis from wild and domestic animals is of great significance in terms of new epidemiological dimensions. Brucellosis poses a major public health threat by the consumption of non-pasteurized milk and milk products produced by unhygienic dairy farms in endemic areas. Regular and meticulous surveillance is essentially required to determine the true picture of brucellosis especially in areas with continuous high prevalence. Additionally, international migration of humans, animals and trade of animal products has created a challenge for disease spread and diagnosis in non-endemic areas. Isolation and identification remain the gold standard test, which requires expertise. The advancement in diagnostic strategies coupled with screening of newly introduced animals is warranted to control the disease. Of note, the diagnostic value of miRNAs for appropriate detection of B. abortus infection has been shown. The most widely used vaccine strains to protect against Brucella infection and related abortions in cattle are strain 19 and RB51. Moreover, it is very important to note that no vaccine, which is highly protective, safe and effective is available either for bovines or human beings. Research results encourage the use of bacteriophage lysates in treatment of bovine brucellosis. One Health approach can aid in control of this disease, both in animals and man.

Brucellosis: Prevalence with reference to East African community countries - A rapid review

Brucellosis is a zoonotic disease which is endemic to certain regions of the world including Sub-Saharan Africa. The aim of this article is to provide a recent and rapid review on brucellosis prevalence in East African Community (EAC) countries. Literature was obtained using Google Scholar search engine and screened for relevancy and fulfilment of criteria to 1, 17, 4, 4, 30 and 29 articles retained for brucellosis prevalence in Burundi, Kenya, Rwanda, South Sudan, Tanzania and Uganda. Recent literature (published in the last decade 2010 to 2019) was considered for prevalence results in this review. In EAC, livestock had an animal-level prevalence of 0.2% to 43.8%, 0.0% to 20.0% and 0.0% to 13.8% for cattle, goats and sheep respectively. In humans, the prevalence varied mostly between 0.0% and 35.8%. In conclusion, brucellosis is quite prevalent in the region. The reported prevalence calls for plans or more efforts from individual member countries and from EAC, as a region, to control brucellosis.

Contamination of milk and dairy products by Brucella species: A global systematic review and meta-analysis

Brucellosis is known as an influential zoonosis in different regions worldwide, with significant effects on the reproductive performance of livestock. Considering the high incidence of brucellosis in dairy products and further negative impacts on food safety, the present study was aimed to systematically investigate prevalence worldwide among published data regarding the identification of Brucella spp. in dairy products. In this regard, some databases, i.e., Scopus, PubMed, Embase, and Web of Science have been searched to retrieve all related articles regarding the incidence of Brucella contaminations in dairy products from 1 January 1983 to 1 April 2019. The prevalence of Brucella spp. in unpasteurized dairy products based on countries, WHO regions, and dairy product subgroups were evaluated and statistically compared. Based on the findings, the prevalence of Brucella spp. in dairy products increased while the GDP (C = 0.17, P-value < 0.001) and HDI (C = 0.19, P-value < 0.001) ranking decreased. Also, the highest prevalence of Brucella contamination in dairy products was noted in buffalo (25.91%) and goat (17.90%), respectively. The lowest and highest prevalence of Brucella spp. were observed in the Western Pacific (15.32%) and the Southeast Asia region (25.55%), respectively. Also, the rank order of WHO regions based on odds ratio (OR) was Southeast Asia region (2.84) > Eastern Mediterranean (2.41) > Region of America (1.65) > European Region (1.54) > Africa region (1.46) > Western Pacific (reference). The results of this study showed that decreasing poverty and an increase in the level of education in societies could reduce the prevalence of Brucella spp. in dairy products. The outcome of the current investigation can be used for the implementation of sustainable intervention and prevention strategies in affected regions.

Human brucellosis caused by raw dairy products: A review on the occurrence, major risk factors and prevention

Despite considerable efforts made to address the issue of brucellosis worldwide, its prevalence in dairy products remains difficult to estimate and represents an important public health issue in many areas of the globe today. This is partly explained by the increasing tendency for consumption of raw dairy products, making the prevention and control of this zoonosis even more critical. This review summarizes reports published since the early 2000s on human brucellosis caused by contaminated dairy products and the systems of evaluation and assessment which are used to improve the diagnosis, surveillance, control and prevention of the disease. For this purpose, five comprehensive electronic databases were investigated and relevant studies were identified for systematic review. The design and quality of the studies revealed notable variation, especially in the methods used for the detection and characterization of Brucella spp. This report provides helpful information about the health risk associated with the consumption of raw milk and relevant preventive strategies.