Brucella spp. at the Wildlife-Livestock Interface: An Evolutionary Trajectory through a Livestock-to-Wildlife “Host Jump”?

Abstract

Brucella infections in wildlife have gained a lot of interest from the scientific community and different stakeholders. These interests are often different and sometimes conflicting. As a result, different management perspectives and aims have been implemented (One Health, public health, veterinary public health, maintenance of a brucellosis free status in livestock, sustainable wildlife harvesting by hunters, wildlife and environmental health). When addressing Brucella infection in wildlife, the most important features of Brucella infection should be considered and the following questions need to be answered: (1) Is Brucella infection a result of a spillover from livestock or is it a sustainable infection in one or more wildlife host species? (2) Did the epidemiological situation of Brucella infection in wildlife change over time and, if so, what are the main drivers of change and does it impact the wildlife population dynamics? (3) Does Brucella infection in wildlife represent a reservoir of Brucella strains for livestock? (4) Is Brucella infection in wildlife of zoonotic concern? These questions point to the fundamental biological question of how animal (domestic and wildlife)/Brucella spp. partnerships are established. Will we be able to decipher an evolutionary trajectory through a livestock-to-wildlife “host jump”? Whole genome sequencing and new “omics” techniques will help in deciphering the molecular basis of Brucella host preference and open new avenues in brucellosis management aimed at preventing opportunities for Brucella host jumps.

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

“…Zone 1, for example, has a higher diversity of wildlife species (i.e., wildlife host species richness) than zone 3, which could increase infectious disease transmission as it may create a large pool of pathogen reservoirs (Daszak et al 2000; Keesing et al 2010) including Brucella spp. which is shared with cattle (Godfroid 2018). Information on brucellosis (Njeru et al 2016) and leptospirosis in wildlife species is very limited in the area and indeed in Kenya, but Brucella spp.…”

Laboratory Diagnosis of Human Brucellosis

“…Although the incidence of human brucellosis in neighboring Israel has been steadily declining for many years countrywide, because of an inconsistent control policy and underfunding, the attack rate among the seminomadic Bedouin inhabitants of the southern Negev desert has increased, reaching a minimal estimate of 100.4 per 100,000 population in 2008 (12). In the developed world, brucellosis has also managed to elude complete eradication because of persistent infection among wildlife with consecutive spillover to domestic animals (13,14), international travel and human migration (15), and illegal import of contaminated dairy products (16). In addition, B. abortus vaccines do not fully prevent B. melitensis infection, and the B. melitensis Rev.1 vaccine has not been evaluated for administration in cattle.…”

Identifying maintenance hosts for infection with Dichelobacter nodosus in free-ranging wild ruminants in Switzerland: A prevalence study

“…The classification into benign and virulent strains was developed in the framework of a study conducted in sheep [10,33] and may only be applicable to sheep. The occurrence of severe lesions associated with both groups of strains in ibex but not in other wild and domestic species suggests the existence of a species-specific difference in disease susceptibility, as it occurs for other pathogens such as Mycoplasma conjunctivae in wild (mostly with marked disease signs) vs domestic Caprinae (mostly without or with only mild signs) and Brucella abortus in North American elk (Cervus canadensis) and Bison (Bison bison) (with signs) vs cattle (without signs) [4,[34][35][36]. As for the other two Alpine ibex that were found positive for benign strains without reported foot lesions but were not sent for veterinary examination, it cannot be ruled out that they may have been in an early stage of infection.…”

“…Whether these lesions were footrot-like could not be confirmed because neither the affected feet nor photographs were submitted for veterinary evaluation. However, D. nodosus has already been isolated from sole ulcers in farmed red deer in New Zealand [35]. Although strain differentiation was not performed, it is likely that it was the benign type based on proteolytic effects observed in bacterial culture and because subsequent experimental infection of sheep resulted in the development of mild footrot lesions only.…”