Brucellosis as an Emerging Threat in Developing Economies: Lessons from Nigeria

Abstract

Nigeria is the most populous country in Africa, has a large proportion of the world's poor livestock keepers, and is a hotspot for neglected zoonoses. A review of the 127 accessible publications on brucellosis in Nigeria reveals only scant and fragmented evidence on its spatial and temporal distribution in different epidemiological contexts. The few bacteriological studies conducted demonstrate the existence of Brucella abortus in cattle and sheep, but evidence for B. melitensis in small ruminants is dated and unclear. The bulk of the evidence consists of seroprevalence studies, but test standardization and validation are not always adequately described, and misinterpretations exist with regard to sensitivity and/or specificity and ability to identify the infecting Brucella species. Despite this, early studies suggest that although brucellosis was endemic in extensive nomadic systems, seroprevalence was low, and brucellosis was not perceived as a real burden; recent studies, however, may reflect a changing trend. Concerning human brucellosis, no studies have identified the Brucella species and most reports provide only serological evidence of contact with Brucella in the classical risk groups; some suggest brucellosis misdiagnoses as malaria or other febrile conditions. The investigation of a severe outbreak that occurred in the late 1970s describes the emergence of animal and human disease caused by the settling of previously nomadic populations during the Sahelian drought. There appears to be an increasing risk of re-emergence of brucellosis in sub-Saharan Africa, as a result of the co-existence of pastoralist movements and the increase of intensive management resulting from growing urbanization and food demand. Highly contagious zoonoses like brucellosis pose a threat with far-reaching social and political consequences.

Brucella seropositivity in chicken and risk factors for Brucella infection at the animal-human interface in Anambra State, Nigeria

“…Since then, the disease has continued to devastate both humans and animals in the country; causing enormous economic losses in animal agriculture [11] and significant health problems in humans [3,12,13], especially among individuals occupationally exposed to brucellosis. About 90% of global brucellosis cases occur in resource-limited developing countries or tropical climatic regions of the world [14,15]; where livestock production is incidentally a major means of livelihood [10,14].…”

“…Brucellosis in animals is transmitted through coitus or use of infected semen during artificial insemination, inhalation of aerosolized Brucella agents, ingestion of tissues or discharges from infected animals, in vivo or in vitro maternal transfer to fetus, and lactation by infected dam [14][15][16][17]. In livestock, the disease manifests as middle or late-term abortion, birth of unthrifty neonates, retained placenta, reduced milk yield, repeat breeder syndrome, increased parturition interval, lameness due to polyarthritis, orchitis, and epididymitis in males [16,17].…”

Brucella abortus surveillance of cattle in Fiji, Papua New Guinea, Vanuatu, the Solomon Islands and a case for active disease surveillance as a training tool

“…Brucellosis is a highly contagious, zoonotic and economically important bacterial disease worldwide that causes significant economic losses from abortion, reduced milk production, low fertility rates and increased cost of replacing cattle (Ducrotoy et al, 2014). It is one of the most important zoonotic diseases in the world as it can impact human health either through direct contact with infected animals or through the consumption of contaminated milk as well as dairy products and it has the potential to also affect animal health (Muhammad et al, 2011).…”

Abattoir characteristics and seroprevalence of bovine brucellosis in cattle slaughtered at Bodija Municipal Abattoir, Ibadan, Nigeria

“…Bovine brucellosis is recognized as an important potential zoonoses in developing countries (McDermott et al, 2013;Ducrotoy et al, 2014). Recently, the World Health Organization has declared brucellosis to be a significant re-emerging zoonoses (World Health Organization [WHO], 2004;Seleem et al, 2010).…”

“…Bovine brucellosis was initially reported in 1927 but first recorded in Nigeria around 1928 (Ducrotoy et al, 2014), while the first case in Southwest Nigeria was reported in 1965 (Ducrotoy et al, 2014). Prevalence of bovine brucellosis between 0.2 and 80% across the different regions of Nigeria as well as between herds have been reported by various authors and summarized by Ducrotoy et al (2014), while institutional and abattoir prevalence between 3.7 and 48.8% have been reported in the Southern part of Nigeria (Cadmus et al, 2010(Cadmus et al, , 2013).…”