The epidemiology of Rift Valley Fever in northern Tanzania

Lead Research Organisation: University of Glasgow
Department Name: College of Medical, Veterinary &Life Sci

Abstract

Studentship strategic priority area: Food Security (Animal Health)
Keywords: Zoonoses, Rift Valley Fever, epidemiology

Rift Valley Fever (RVF) is an important anthropod zoonosis that can cause severe disease in both humans, ruminant livestock and wildlife. The disease typically occurs as large outbreaks in association with periods of heavy rainfall when mosquito vectors proliferate, with RVF virus (RVFV) persisting in dormant eggs of Aedes mosquitos in periods between epidemics. However, recent evidence indicates that RVF virus also circulates in mammalian hosts and mosquitoes between epidemics, and very little is known about patterns of circulation or mechanisms of during the inter-epidemic period. Furthermore, little is known about the socio-economic impacts of RVF in Tanzania during both epidemic and inter-epidemics period.

This project aims to investigate the epidemiology of RVF in multi-host ecosystems of northern Tanzania with the following objectives:

(a) to determine patterns of RVF virus infection in mosquitoes in relation to livestock density, livestock infection prevalence, rainfall and vegetation through longitudinal sampling and PCR analysis of mosquitoes collected from sites at wildlife-livestock interfaces;
(b) to investigate the relationship between infection patterns in mosquitoes, livestock and human infection and disease risk in areas surrounding wildlife-protected areas through linkage of mosquito PCR data with serological data from linked human and livestock populations;
(c) to determine risk factors for RVF seropositivity in livestock and human populations in areas surround wildlife-protected areas through analysis of human and livestock serological data collected from cross-sectional household surveys;
(d) to carry out RVF serological analyses of archived wildlife sera to investigate risk factors for infection for wildlife;
(e) to develop epidemiological models of RVFV in multi-host systems in order to explore potential strategies, such as livestock vaccination, to reduce the risk of major outbreaks.
(f) to determine the socio-economic impact of RVF in northern Tanzania through collection of data on livestock production losses during outbreaks (which are anticipated during the PhD study period).

The PhD project will be closely linked with two projects within the NNSRC Zoonoses and Emerging Livestock Systems (ZELS) scheme - "Social, Economic and Environmental Drivers of Zoonoses in Tanzania" (SEEDZ) and "Life on the Edge: Tackling human African Trypanosomiasis on the edge of wilderness areas"

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
BB/N503563/1 01/10/2015 30/09/2019
1654039 Studentship BB/N503563/1 11/01/2016 30/06/2019 Marku James Nyarobi
 
Description Serology results shows an overall prevalence of 2.6% (95%CI: 2.28-3.04) in livestock (cattle, sheep and goats) and Overall 8.89% (CI: 6.65-11.77) in humans. This gives evidence for inter-epidemic circulation of Rift Valley fever virus in livestock and humans in Northern Tanzania.
Entomological study results shows varied abundance and distribution of the vector for RVFV (Aedes spp, Culex spp, Mansonia spp and Anopheles spp) in northern Tanzania.
Predicted vector habitat suitability maps were produced to aid future studies and/or disease surveillance and control programs.
Exploitation Route These findings can inform disease surveillance, preparedness, prevention and control programs by researchers, veterinary and public health sectors, policy makers and the general public.
Sectors Agriculture, Food and Drink,Communities and Social Services/Policy,Digital/Communication/Information Technologies (including Software),Education,Environment,Financial Services, and Management Consultancy,Healthcare,Government, Democracy and Justice,Pharmaceuticals and Medical Biotechnology

 
Description Community awareness about the disease, Rift Valley fever and that they need to report whenever they notice any suspicious signs of the disease in their households or villages.
First Year Of Impact 2017
Sector Agriculture, Food and Drink,Communities and Social Services/Policy
Impact Types Societal

 
Description Animal samples for testing laboratory assays, from Sokoine University of Agriculture, Tanzania 
Organisation Sokoine University of Agriculture
Country Tanzania, United Republic of 
Sector Academic/University 
PI Contribution Received animal samples for testing the performance of a laboratory assay used in my study
Collaborator Contribution Generous offer of animal samples to be use to test the performance of a laboratory assay
Impact Choice of a better assay to use for testing of the samples for my study. Feedback on the performance of the assay and the potential for doing further work together.
Start Year 2018
 
Description Training on Field mosquito trapping techniques at Ifakara Health Institute (IHI), Tanzania 
Organisation Ifakara Health Institute
Country Tanzania, United Republic of 
Sector Charity/Non Profit 
PI Contribution Received one week training on field mosquito trapping techniques including the use of Mosquito Electrocuting Trap (MET) and Resting buckets.
Collaborator Contribution IHI offered the expert and the field team to work with for one week.
Impact Mosquito trapping methods used in my PhD Study
Start Year 2016
 
Description Training on identification of Mosquito vectors of Rift Valley fever virus (RVFV) and other arbovirus at the NICD, South Africa 
Organisation Centre for HIV and Sexually Transmitted Infections, National Institute for Communicable Diseases, National Health Laboratory Service in Johannesburg
Country South Africa 
Sector Hospitals 
PI Contribution Attended the training workshop on identification of mosquito vectors of RVFV and other arbovirus at the National Institute for Communicable Diseases (NICD), South Africa. The workshop was supported by the ECOHEALTH Alliance.
Collaborator Contribution Training expertise and facilities
Impact Mosquito trapping and identification methods used in my study
Start Year 2017
 
Description Local leaders/village meetings 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Meeting with local leaders at district and village level explaining the study objectives and the importance of the study. This was carried out in farming communities in northern Tanzania with history of Rift Valley fever outbreaks.
Year(s) Of Engagement Activity 2006,2007
 
Description ZELS Grant holders meeting 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Supporters
Results and Impact Shared findings of my research study to funding agencies representatives, PIs and postgraduate students at the ZELS grant holders meetings, one in Tanzania (February 2017) and another in Vietnam (February, 2018)
Year(s) Of Engagement Activity 2017,2018