title: The Sero-epidemiology of Coxiella burnetii in Humans and Cattle, Western Kenya: Evidence from a Cross-Sectional Study.
abstract: Evidence suggests that the intracellular bacterial pathogen Coxiella burnetii (which causes Q fever) is widespread, with a near global distribution. While there has been increasing attention to Q fever epidemiology in high-income settings, a recent systematic review highlighted significant gaps in our understanding of the prevalence, spatial distribution and risk factors for Q fever infection across Africa. This research aimed to provide a One Health assessment of Q fever epidemiology in parts of Western and Nyanza Provinces, Western Kenya, in cattle and humans. A cross-sectional survey was conducted: serum samples from 2049 humans and 955 cattle in 416 homesteads were analysed for C. burnetii antibodies. Questionnaires covering demographic, socio-economic and husbandry information were also administered. These data were linked to environmental datasets based on geographical locations (e.g., land cover). Correlation and spatial-cross correlation analyses were applied to assess the potential link between cattle and human seroprevalence. Multilevel regression analysis was used to assess the relationships between a range of socio-economic, demographic and environmental factors and sero-positivity in both humans and animals. The overall sero-prevalence of C. burnetii was 2.5% in humans and 10.5% in cattle, but we found no evidence of correlation between cattle and human seroprevalence either within households, or when incorporating spatial proximity to other households in the survey. Multilevel modelling indicated the importance of several factors for exposure to the organism. Cattle obtained from market (as opposed to those bred in their homestead) and those residing in areas with lower precipitation levels had the highest sero-prevalence. For humans, the youngest age group had the highest odds of seropositivity, variations were observed between ethnic groups, and frequent livestock contact (specifically grazing and dealing with abortion material) was also a risk factor. These results illustrate endemicity of C. burnetii in western Kenya, although prevalence is relatively low. The analysis indicates that while environmental factors may play a role in cattle exposure patterns, human exposure patterns are likely to be driven more strongly by livestock contacts. The implication of livestock markets in cattle exposure risks suggests these may be a suitable target for interventions.
authors.affiliation: Geography and Environment, University of Southampton, Southampton, United Kingdom.
authors.forename: Nicola A
authors.identifier: http://orcid.org/0000-0001-7401-4841
authors.initials: NA
authors.lastname: Wardrop
authors.affiliation: Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom.|International Livestock Research Institute, Nairobi, Kenya.
authors.forename: Lian F
authors.initials: LF
authors.lastname: Thomas
authors.affiliation: Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom.|International Livestock Research Institute, Nairobi, Kenya.
authors.forename: Elizabeth A J
authors.initials: EA
authors.lastname: Cook
authors.affiliation: Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom.|International Livestock Research Institute, Nairobi, Kenya.|Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom.
authors.forename: William A
authors.initials: WA
authors.lastname: de Glanville
authors.affiliation: Geography and Environment, University of Southampton, Southampton, United Kingdom.|Faculty of Science and Technology, Lancaster University, Lancaster, United Kingdom.|School of Geography, Archaeology and Palaeoecology, Queen's University Belfast, Belfast, United Kingdom.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Atkinson
authors.affiliation: Centre for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya.|Mount Kenya University, Thika, Kenya.
authors.forename: Claire N
authors.initials: CN
authors.lastname: Wamae
authors.affiliation: International Livestock Research Institute, Nairobi, Kenya.|Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Fèvre
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood* / Q000201:enzymology / Q000276:immunology / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D016997:Coxiella burnetii / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D007630:Kenya / Q000453:epidemiology; D058751:Livestock; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011778:Q Fever / Q000097:blood* / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology; D016036:Seroepidemiologic Studies; D055815:Young Adult; D015047:Zoonoses / Q000097:blood / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology
chemical_list: D000907:Antibodies, Bacterial