Early Cytokine Response After Vaccination with Coxiella Burnetii Phase I in an Infected Herd of Dairy Cattle

Coxiella burnetii infections from animals and ticks in South Africa: a systematic review

Coxiella burnetii is a zoonotic intracellular bacterium that is widely distributed and affects domestic animals, wildlife, humans and non-mammalian species. This systematic review was aimed at synthesizing research findings on C. burnetii in both domestic and wild animals of South Africa. The systematic review protocol was registered with Open Society Foundations of systematic reviews ( https://doi.org/10.17605/OSF.IO/8WS ). PRISMA guidelines were followed to collect and evaluate relevant scientific articles published on C. burnetii infecting domestic and wild animals in South Africa. Published articles were sourced from five electronic databases, namely, Google Scholar, PubMed and ScienceDirect, EBSCO and Scopus. Results showed 11 eligible studies involving four domestic animals, three wild animals and one ectoparasite species from seven provinces across South Africa. The occurrence of C. burnetii infection was high in Ceratotherium simum (white rhinoceros) (53.9%), medium in sheep (29.0%) and low in pigs (0.9%). Limpopo province (26%) had the most recorded infections followed by KwaZulu-Natal (19%) and Free State (3%) had the least reported occurrence of C. burnetii. The current study discovered that there is scarcity of published research on prevalence and distribution of C. burnetii infecting domestic and wild animals in South Africa, and this is of concern as this bacterium is an important zoonotic pathogen of "One Health" importance.

Recent Advances on the Innate Immune Response to Coxiella burnetii

Coxiella burnetii is an obligate intracellular Gram-negative bacterium and the causative agent of a worldwide zoonosis known as Q fever. The pathogen invades monocytes and macrophages, replicating within acidic phagolysosomes and evading host defenses through different immune evasion strategies that are mainly associated with the structure of its lipopolysaccharide. The main transmission routes are aerosols and ingestion of fomites from infected animals. The innate immune system provides the first host defense against the microorganism, and it is crucial to direct the infection towards a self-limiting respiratory disease or the chronic form. This review reports the advances in understanding the mechanisms of innate immunity acting during C. burnetii infection and the strategies that pathogen put in place to infect the host cells and to modify the expression of specific host cell genes in order to subvert cellular processes. The mechanisms through which different cell types with different genetic backgrounds are differently susceptible to C. burnetii intracellular growth are discussed. The subsets of cytokines induced following C. burnetii infection as well as the pathogen influence on an inflammasome-mediated response are also described. Finally, we discuss the use of animal experimental systems for studying the innate immune response against C. burnetii and discovering novel methods for prevention and treatment of disease in humans and livestock.