A systematic literature review of milk consumption and associated bacterial zoonoses in East Africa.

Consumption of unsafe animal-source foods is the major cause of foodborne disease outbreaks in low-income countries. Despite current knowledge of the threat posed by raw milk consumption to human health, people in many countries in East Africa still consume unboiled milk. This literature review explored the association between milk consumption and the occurrence of five milk-borne bacterial zoonoses: brucellosis, salmonellosis, campylobacteriosis, Escherichia coli infections, and tuberculosis. A search for literature published up to 1 October 2021 was conducted through the Web of Science, PubMed, and Scopus databases, using Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. The selection process yielded 65 articles describing studies conducted in East Africa 2010-2021, which were carefully scrutinized. The most investigated pathogen was Brucella spp. (54.5%), followed by E. coli (18.2%), Salmonella spp. (12.1%), Mycobacterium spp. (6.1%), and E. coli O157: H7 (6.1%). The most common predisposing factors for potential milk-borne disease outbreaks were consumption of contaminated raw milk, inadequate cold storage along the milk value chain, poor milk handling practices, and lack of awareness of the health risks of consuming unpasteurized milk. Thus, a tailor-made training program is needed for all milk value chain actors to enhance the safety of milk sold in informal markets, and a One Health approach should be applied. Future studies should employ more advanced diagnostic techniques and countries in East Africa should invest in modern diagnostic tools and equipment, both in hospitals and in local rural settings where most cases occur.

Field validation of clinical and laboratory diagnosis of wildebeest associated malignant catarrhal fever in cattle.

BACKGROUND: Wildebeest associated malignant catarrhal fever (WA-MCF) is a fatal disease of cattle. Outbreaks are seasonal and associated with close interaction between cattle and calving wildebeest. In Kenya, WA-MCF has a dramatic effect on cattle-keepers who lose up to 10% of their cattle herds per year. The objective of this study was to report the impact of WA-MCF on a commercial ranch and assess the performance of clinical diagnosis compared to laboratory diagnosis as a disease management tool. A retrospective study of WA-MCF in cattle was conducted from 2014 to 2016 at Kapiti Plains Ranch Ltd., Kenya. During this period, 325 animals showed clinical signs of WA-MCF and of these, 123 were opportunistically sampled. In addition, 51 clinically healthy animals were sampled. Nested polymerase chain reaction (PCR) and indirect enzyme linked immunosorbent assay (ELISA) were used to confirm clinically diagnosed cases of WA-MCF. A latent class model (LCM) was used to evaluate the diagnostic parameters of clinical diagnosis and the tests in the absence of a gold standard. RESULTS: By PCR, 94% (95% C.I. 89-97%) of clinically affected animals were positive to WA-MCF while 63% (95% C.I. 54-71%) were positive by indirect ELISA. The LCM demonstrated the indirect ELISA had poor sensitivity 63.3% (95% PCI 54.4-71.7%) and specificity 62.6% (95% PCI 39.2-84.9%) while the nested PCR performed better with sensitivity 96.1% (95% PCI 90.7-99.7%) and specificity 92.9% (95% PCI 76.1-99.8%). The sensitivity and specificity of clinical diagnosis were 99.1% (95% PCI 96.8-100.0%) and 71.5% (95% PCI 48.0-97.2%) respectively. CONCLUSIONS: Clinical diagnosis was demonstrated to be an effective method to identify affected animals although animals may be incorrectly classified resulting in financial loss. The study revealed indirect ELISA as a poor test and nested PCR to be a more appropriate confirmatory test for diagnosing acute WA-MCF. However, the logistics of PCR make it unsuitable for field diagnosis of WA-MCF. The future of WA-MCF diagnosis should be aimed at development of penside techniques, which will allow for fast detection in the field.

A one health framework to advance food safety and security: An on-farm case study in the Rwandan dairy sector.

In Rwanda, cattle and milk hold a cultural and historical significance, providing an opportunity for pro-dairy governmental policies aimed to alleviate food insecurity, malnutrition, and improve livelihoods. The government of Rwanda has identified strategies to grow the dairy sector through strategic investment to achieve these goals. It is estimated two-thirds of lactating cows in Rwanda have clinical or subclinical mastitis, which reduces milk production and increases the risk of milk as a source for zoonotic disease if the milk is consumed undercooked or unpasteurized. This case study outlines the implementation of a One Health framework that integrates education, research, and outreach in Rwanda to improve food safety and food security, for the social, economic, and health benefit of Rwandans and their livestock. Twenty-five Rwandan Extension Specialists participated in the Dairy Dynamic Management education, research, and outreach program. Once trained, the extension specialists supported 30 small holder dairy farmers in performing proper husbandry and animal health practices for mastitis control and reduction of bacterial counts in the udder. Over the 16-week program, 30 small holder dairy farmers and 100 dairy cows were surveyed weekly for animal husbandry, animal health, and mastitis indicators. Outcomes were evaluated by monitoring animal health, foodborne pathogens in milk, and compliance to animal husbandry protocols. Quarter milk samples were collected weekly and evaluated for the presence of bacteria that are common causes of mastitis. We found a statistically significant reduction of mean total bacterial counts and prevalence of bacterial species in quarters over the 16-week training (P ≤ .01). Smallholders were monitored through observing farmers performing hygienic milking protocols. Farmers conducted the protocol correctly greater than 90% of the time by the end of the 16-week program for 5 of 7 steps for proper hygienic milking procedures, indicating farmers were eager to learn and adopt the procedures. However, follow-up and retraining with Extension Specialists is vital to continued success. We demonstrate that an integrative One Health education, research, and outreach program can be successful in improving animal health, food safety, and food security and this framework can be applied to other agricultural sectors and geographic regions.