Human-bat interactions and diseases: transmission risks in Ghana
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Transcript of Human-bat interactions and diseases: transmission risks in Ghana
Human-bat interactions and
diseases transmission risks in Ghana
(DDDAC, London, UK. March 17, 2016)
Presented on behalf of the Ghana Team
by
Yaa Ntiamoa-Baidu
Ghana Study Team
UK
James L. N. Wood
Andrew A. Cunningham
Linda Waldman
Melissa Leach
Kate Jones
Ghana
Yaa Ntiamoa-Baidu
Elaine T. Lawson
Richard D. Suu-Ire
Kofi Amponsah-Mensah
Fidelia Ohemeng
Jesse S. Ayivor
Introduction: Fruit Bats in Ghana
Epomophorus gambianus
Micropteropus pusillus
Eidolon helvum
Thirteen species reported in
Ghana, ten recorded in current
study
Occur all across the country
Most abundant species are:
Eidolon helvum & Epomophorus
gambianus
Introduction (ii): Bats & Disease
Globally, approx. 70% emerging/re-
emerging human infections are
zoonotic
Bats are known to be reservoirs of
zoonotic viruses; more than sixty
viruses have been detected in bat
tissue, including:
• Filoviruses (Ebola & Marburg)
• Lyssaviruses (rabies-like viruses)
• Coronaviruses (e.g. SARS)
• Henipaviruses (Hendra & Nipah
viruses)- cause encephalitic
disease in humans and domestic
animals with extremely high case
fatality rates
The Ghana Case Study
Overarching hypotheses:
Spillover of henipavirus is occurring
in Ghana and there are high risk
groups for henipavirus exposure,
based on ecosystem service use
practices
Spillover dynamics and henipavirus
transmission differ between urban
and rural sites due to changes in
biodiversity and land use.
Ghana Study Sites
Study sites
37 Military Hospital
Tano Sacred Grove Ve-Golokuati
Components of the Ghana Study
Multidisciplinary Team of Ecological, Veterinary
& Social Scientists
Sociological studies: historical,
social and cultural dimensions
and understandings of bats and
disease.
Disease dynamics: surveillance of bats, domestic
animals and human populations
for evidence of henipavirus sero-
prevalence
Ecological Studies: mapping
distribution/population dynamics
of bats
Human-bat interactions: where are the
bats?
Nearly 6000 bats belonging to ten
species caught & sampled
Eidolon helvum and Epomophorus
gambianus accounted for > 75%
Roosts reported from 86 locations;
95% of roosts investigated occurred
within 50m of buildings/homes
Several bat roosts are in cities and
towns - high possibility of human
interaction with bats/ multiple
opportunities for disease spillover.
Human-bat interactions: how do humans
interact with bats?
340 respondents were involved in the semi-structured
interviews in the three sites:
164 females and 176 males,
aged 15 years and above,
educational background ranging from no formal education to
tertiary level education.
Livelihood activities
Farming/gardening
Petty trading
Artisans/construction workers
Food processing/trading
Government workers-teaching/health service/military service
Human-bat interactions: how do humans
interact with bats?
Direct exposure to bats
Hunting
Processing fresh bat meat for
consumption
Sale of fresh bat meat
Consumption (in case of improperly
cooked fresh bat meat)
Human-bat interactions: how do humans
interact with bats?
Indirect exposure to bats:
livelihood options Farming
Fruit collection
Trading/selling of wares under
bat roosts
Domestic animal husbandry
Human-bat interactions: how do humans
interact with bats?
Living with bats
(Golokuati)
Household chores: food
preparation in the open under bat roosts)
Human-bat interactions: how do humans
interact with bats?
Rain water harvesting in open
containers for domestic use and
drinking
Recreation under bat roosts -
schools /church grounds
Henipavirus sero-prevalence analyses
Preliminary data based on Luminex binding indicate
henipavirus spillover from bats to people is occurring in
Ghana
More detailed analyses need to be conducted to confirm
and investigate risk factors.
So what does all this mean?
Plowright et al., (2015) - series of hierarchical enabling conditions required for spillover to occur:
Reservoir hosts must be present
Reservoir hosts must be infected
If transmission is indirect, reservoir hosts must be shedding
pathogen and virus must survive outside of its reservoir host with
access to the recipient host
Recipient hosts must be exposed to the source of the virus in
sufficient quantity for an infection to establish
Recipient hosts must be susceptible to the virus
Assessing disease risks
GOLOKUATI TANO GROVE
Main Bat Species Epomophorus gambianus Eidolon helvum
Presence of Virus Presence of henipavirus
established
Presence of henipavirus
established
Direct exposure Limited hunting/processing fresh
bat meat
Regular
hunting/processing & sale
of fresh bat meat
Indirect exposure Living with bats (number of
houses with trees with Bat roost
Livelihood options –
(trading/buying, activities in
market place )
Recreational activities
Rain water collection
Livelihood options –
farming, collection of
forest products
CONCLUSION
Bats are found in many places in Ghana and in close
proximity of human habitation
Livelihood options and social activities greatly facilitate
interactions between people and bats (ecosystem
services and dis-services)
Multiple opportunities for disease spillover
Major implications for policy/health/poverty
A great need for systematic surveillance of zoonotic
diseases in humans, domestic animals and target wild
animal species
This work, Dynamic Drivers of Disease in Africa Consortium, NERC project numberNE-J001570-1, was funded with support from the Ecosystem Services for Poverty Alleviation (ESPA)programme. The ESPA programme is funded by the Department for International Development (DFID), theEconomic and Social Research Council (ESRC) and the Natural Environment Research Council (NERC).