Wellcome Trust Integrative Infection Biology PhD

Multi-host epidemiology and molecular diversity of Coxiella burnetii

 

Supervisor: Dr Jo Halliday, One Health & Veterinary Medicine 

 

Rotation Project:

Coxiella burnetii is a bacterial pathogen that causes febrile disease in humans and significant production losses in economically crucial livestock species (e.g. cattle, sheep and goats) globally. There is evidence that C. burnetii genotypes vary in their pathogenicity and epidemiology, but robust data on data the distribution and clinical and production significance of different genotypes in different global settings is lacking.

C.burnetii is endemic in Tanzania, where C. burnetii infection, also known as Q fever, causes substantial burdens of human illness. Serological and molecular testing reveals that C. burnetii exposure is common in livestock and bacterial carriage and shedding by goats, cattle and rodents provides evidence of the complex multi-host epidemiology of this important pathogen in Tanzania.

Despite growing recognition of the widespread distribution of C. burnetii in ruminant populations globally and the zoonotic impacts of Q fever in many global contexts, considerable gaps remain in our understanding of the relationships between diagnostic test outcome data and epidemiological parameters, the influence of variation in genotypes on epidemiology and pathogenicity of Q fever and the dynamics of transmission between host species. This lack of knowledge impedes current efforts to evaluate candidate surveillance and control measures that are applicable and appropriate for these epidemiological contexts.

This project will generate and analyse molecular detection and genotyping data to advance our understanding of the multi-host epidemiology and transmission dynamics of C. burnetii in Tanzania.  The project will build on access to previously collected samples from human, livestock and wildlife populations from Tanzania with opportunities for prospective sampling and data collection.

Specific objectives may vary depending on the candidates’ preferences, with scope for project development in multiple directions.  Potential areas of focus include:

• Characterisation of the genetic diversity of burnetii detected in multiple hosts

 

• Analyses of linked laboratory (detection and genotyping) and epidemiological data to quantify transmission routes within and between animal populations and identify risk factors for human exposure and disease

• Quantification of the livestock production and human health impacts of Q fever and to inform evaluation of context appropriate disease control interventions

Training opportunities will span the application and use of data from multiple diagnostic technologies and diverse epidemiological analyses with opportunities to work within an interdisciplinary team on this One Health challenge. Work will include colleagues at the Institute for Biodiversity Animal Health and Comparative Medicine and the School of Veterinary Medicine.

References:

Pisharody et al. (2021) Incidence Estimates of Acute Q Fever and Spotted Fever Group Rickettsioses, Kilimanjaro, Tanzania, from 2007 to 2008 and from 2012 to 2014. Am J Trop Med Hyg doi: 10.4269/ajtmh.20-1036.

Salifu, S. P., Bukari, A. A., Frangoulidis, D. & Wheelhouse, N. Current perspectives on the transmission of Q fever: Highlighting the need for a systematic molecular approach for a neglected disease in Africa. Acta Trop 193, 99-105 (2019).

Vanderburg S., Rubach, M.P., Halliday, J.E.B., Cleaveland, S., Reddy, E.A. & Crump, J.A. (2014) Epidemiology of Coxiella burnetii infection in Africa: a OneHealth Systematic Review. PLoS Negl Trop Dis. 8 (4): e2787.