Postdoctoral Fellow, Eco-epidemiologist (modelling dynamic disease systems)
- WSU Paul G. Allen School for Global Health
- Vetworks EA
- Kenya Veterinary Association
Dr. John Gachohi is a Post-Doctoral Fellow at the Washington State University Global Health Program - Kenya. He holds a Bachelor of Veterinary Medicine and Master of Science (MSc) and PhD degrees in Epidemiology from the University of Nairobi, Kenya. His initial MSc research training is in classic, spatial and participatory epidemiology, but he gained extensive experience in infectious disease modelling (individual-based and mathematical) during his PhD training. Over the past 15 years, he has been involved in field studies in infectious diseases resulting in publication of twenty peer-reviewed papers. These studies constituted diseases such as African Animal Trypanosomiasis, East Coast Fever, Anaplasmosis, Babesiosis, Theirelia mutans infection, pig-mediated zoonoses and other pig parasites, Peste-des petits ruminants (PPR) and Rift Valley fever and currently anthrax and MERSCov in camels. Since 2014, John has been a faculty staff in the School of Public Heath, Jomo Kenyatta University of Agriculture and Technology (JKUAT) teaching the following postgraduate course work units: Epidemiology, Biostatistics and Demography, Research Methodology, Health Programmes and Health Research and Computer Applications in Health Research. In addition, he teaches the following undergraduate course units: Biostatistics and Research Methodology, Food Inspection and Hygiene, Environmental Health and Health Economics.
While I did not plan to become a veterinarian, pursuing epidemiologic research was deliberate. I have strong interests in understanding the entire (multilevel-hierarchical) causative chain in infectious and non-infectious disease dynamics for better health - the chain extends from the highest level - the social and structural community-specific, physical landscape and environmental influences; then risk factor epidemiology on behaviors and exposures at the individual level (level 2) and molecular epidemiology on biological mechanisms (level 1). I fully recognize that such a perspective must allow for greater methodological pluralism that includes (i) classical quantitative epidemiology that embraces simulation modeling, risk analyses, spatial epidemiology, etc and (ii) qualitative epidemiology, all in systems- thinking approach. More was to come when an opportunity came to join “academic” epidemiology in the School of Public Health, Jomo Kenyatta University of Agriculture and Technology (JKUAT) in the outskirts of Nairobi, Kenya. I was then and continue to be enthusiastic about being able to conduct research and teach epidemiology in a way that meaningfully contributes to the growth of the discipline. I have progressively grown in the hands of seniors while at the same time had the privilege of working to help my juniors improve in their understanding and skill, recognizing that that there is both a learner and a teacher in me. Outside the epidemiology lab and class, I find music, reading biographies and travelling satisfying my heart.
Education and Training
- 1990-1996. Bachelor of Veterinary Medicine (BVM), University of Nairobi, Nairobi, Kenya
- 2005-2009. Master of Science, University of Nairobi, Nairobi, Kenya
- 2011-2015. Doctor of Philosophy, University of Nairobi, Nairobi, Kenya
- 2017- . Postdoctoral Fellowship, Washington State University Global Health Program - Kenya
General Research / Expertise
Presently, John is leading in the implementation and coordination of a project funded by the US Department of Defense, Defense Threat Reduction Agency (DTRA) whose objective is to identify anthrax hotspots and associated ecological factors in Kenya. John is also involved in an urban slum project seeking to source eco-epidemiological field parameters to describe a slum household-based pathogenic Leptospira population dynamics simulation model. John is also currently collaborating with geospatial scientists in Ethiopia in developing a global atlas of podoconiosis.
Thus far John’s research contribution has been in the application of multi-level ecoepidemiology principles in infectious disease dynamics. Currently, he is pursuing a trajectory of integrating multi-level ecoepidemiology principles and systems science methods (dynamics, networks and agents).
This way, an advanced understanding of how micro-level, individual, and macro-level determinants and processes shape infectious disease emergence and spread in human and animal populations may be achieved.
Two areas in which John’s research has been impactful.
1. Epidemiology of tick-borne diseases in Kenya.
John has worked extensively in the epidemiology of tick-borne infections in Kenya. Amongst major highlights from these works included estimating intra-farm correlation coefficients for Theileria parva, Anaplasma marginale, Babesia bigemina and Theileria mutans infections. These analyses have major implications on whether to target control at the individual animal-level or at the farm-level. These coefficients can also inform the design effects needed to adjust for cluster sampling in future tick-borne diseases surveys. This research also estimated population attributable fractions of farm Rhipicephalus appendiculatus presence on Theileria parva infection seroprevalence under endemic instability and concluded that presence of the vector tick was not a good indicator of the infection occurrence on a farm; Finally, a probable differential ecological and climatic variability in vector suitability habitats was suggested to influence farm tick control management across the area. This has policy implications as well. The outcome of these studies were published in 6 manuscripts.
2. Simulation modelling of Vaccination Strategies against Rift Valley Fever in Livestock in Kenya
John developed a RVFV transmission model comprising two hosts (cattle and sheep) and two vectors Aedes and Culex spp and used it to predict the impacts of: (1) reactive vaccination implemented at various levels of coverage at pre-determined time points, (2) targeted vaccination involving either of the two host species, and (3) a periodic vaccination implemented biannually or annually before an outbreak. This research demonstrated that reactive vaccination can be effective in mitigating the impacts of RVF outbreaks but practically, it is not always possible to have this measure implemented satisfactorily due to the rapid onset and evolution of RVF epidemics. Going forward, both periodic and reactive vaccination ought to be used strategically to effectively control the disease.
- Apat D, Gachohi J, Karama M, Kiplimo J, Sachs S. (2017) Temporal variation in confirmed diagnosis of fever-related malarial cases among children under-5 years by community health workers and in health facilities between years 2013 and 2015 in Siaya County, Kenya. Journal of Malaria 16(1):454. doi: 10.1186/s12936-017-2100-9. PMID: 29121954 PMCID: PMC5679183
- Muli J, Gachohi J, Kagai J. (2017) Soil iron and aluminium concentrations and feet hygiene as possible predictors of Podoconiosis occurrence in Kenya. PLoS Negl Trop Dis. 11(8):e0005864. doi: 10.1371/journal.pntd.0005864 PMID: 28832604 PMCID: PMC5584976
- Gachohi JM, Njenga MK, Kitala P, Bett B. (2016) Modelling Vaccination Strategies against Rift Valley Fever in Livestock in Kenya. PLoS Negl Trop Dis. 10(12):e0005049. doi: 10.1371/journal.pntd.0005049. PMID: 27973528 PMCID: PMC5156372
- Gachohi JM, Ngumi PN, Kitala PM, Skilton RA. (2010) Estimating seroprevalence and variation to four tick-borne infections and determination of associated risk factors in cattle under traditional mixed farming system in Mbeere District, Kenya. Prev. Vet Med. 95(3-4):208-23. doi: 10.1016 PMID: 20434227 PMCID: