Systematic review of brucellosis in Kenya: disease frequency in humans and animals and risk factors for human infection

Abstract

BackgroundBrucellosis is a debilitating zoonotic disease affecting humans and animals. A comprehensive, evidence-based assessment of literature and officially available data on animal and human brucellosis for Kenya are missing. The aim of the current review is to provide frequency estimates of brucellosis in humans, animals and risk factors for human infection, and help to understand the current situation in Kenya.MethodsA total of accessible 36 national and international publications on brucellosis from 1916 to 2016 were reviewed to estimate the frequency of brucellosis in humans and animals, and strength of associations between potential risk factors and seropositivity in humans in Kenya.ResultsThe conducted studies revealed only few and fragmented evidence of the disease spatial and temporal distribution in an epidemiological context. Bacteriological evidence revealed the presence of Brucella (B.) abortus and B. melitensis in cattle and human patients, whilst B. suis was isolated from wild rodents only. Similar evidence for Brucella spp infection in small ruminants and other animal species is unavailable. The early and most recent serological studies revealed that animal brucellosis is widespread in all animal production systems. The animal infection pressure in these systems has remained strong due to mixing of large numbers of animals from different geographical regions, movement of livestock in search of pasture, communal sharing of grazing land, and the concentration of animals around water points. Human cases are more likely seen in groups occupationally or domestically exposed to livestock or practicing risky social-cultural activities such as consumption of raw blood and dairy products, and slaughtering of animals within the homesteads. Many brucellosis patients are misdiagnosed and probably mistreated due to lack of reliable laboratory diagnostic support resulting to adverse health outcomes of the patients and routine disease underreporting. We found no studies of disease incidence estimates or disease control efforts.ConclusionThe risk for re-emergence and transmission of brucellosis is evident as a result of the co-existence of animal husbandry activities and social-cultural activities that promote brucellosis transmission. Well-designed countrywide, evidence-based, and multidisciplinary studies of brucellosis at the human/livestock/wildlife interface are needed. These could help to generate reliable frequency and potential impact estimates, to identify Brucella reservoirs, and to propose control strategies of proven efficacy.

Risk factors for acute human brucellosis in Ijara, north-eastern Kenya

“…We also show that boiling milk before consumption was strongly protective against brucellosis. This supports the findings of a number of other studies in East Africa showing either protective effects of boiling milk or increased risks with consuming it raw [8,11,24,44]. Health education messages that encourage safe milk preparation in the home could therefore also be expected to lead to a reduction in the incidence of brucellosis in Ijara.…”

“…The prevalence of Brucella spp. infection in livestock is often highest in arid and semi-arid areas, and particularly where cattle, small ruminants and/or camels are reared in large herds or flocks under extensive management [1,11,12]. Control programmes that aim to reduce the human health impacts of Brucella spp.…”

“…Firstly, to inform the development of public health interventions intended to reduce the incidence of human brucellosis and secondly, to contribute epidemiological information that can inform diagnostic decision making in individuals presenting to health facilities with febrile illness in north eastern Kenya. Recent work has suggested the prevalence of human brucellosis in Garissa County is likely to be high [11,24]. We therefore also aim to assess the performance of the FBAT in the diagnosis of acute human brucellosis in a high prevalence setting.…”

Molecular Investigation of the Transmission Dynamics of Brucellosis Observed Among Children in the Province of South - East Anatolia, Turkey

“…Brucellosis is an infectious disease, caused by Brucella species and remains one of the most common zoonotic diseases worldwide. The disease is highly prevalent in many regions, particularly in central Asia, Middle East, the Mediterranean region, Africa, and Latin America (1,2). Brucellosis causes abortion, sterility, mastitis in animals, and leads to great economic losses (3,4).…”

Detection ofBrucella abortusB19 strain DNA in seminal plasma by polymerase chain reaction in Brazil

“…Another relevant data of this current study are the public health concern, as humans are susceptible to B. abortus B19 strain and may develop fever, headache and muscle and joint pain (Njeru et al, 2016). Workers who handle these animals are exposed to risk without their knowledge, because the bulls are clinically healthy and negative in serological tests.…”