Wildlife Trade and Human Health in Lao PDR: An Assessment of the Zoonotic Disease Risk in Markets

Abstract

Although the majority of emerging infectious diseases can be linked to wildlife sources, most pathogen spillover events to people could likely be avoided if transmission was better understood and practices adjusted to mitigate risk. Wildlife trade can facilitate zoonotic disease transmission and represents a threat to human health and economies in Asia, highlighted by the 2003 SARS coronavirus outbreak, where a Chinese wildlife market facilitated pathogen transmission. Additionally, wildlife trade poses a serious threat to biodiversity. Therefore, the combined impacts of Asian wildlife trade, sometimes termed bush meat trade, on public health and biodiversity need assessing. From 2010 to 2013, observational data were collected in Lao PDR from markets selling wildlife, including information on volume, form, species and price of wildlife; market biosafety and visitor origin. The potential for traded wildlife to host zoonotic diseases that pose a serious threat to human health was then evaluated at seven markets identified as having high volumes of trade. At the seven markets, during 21 observational surveys, 1,937 alive or fresh dead mammals (approximately 1,009 kg) were observed for sale, including mammals from 12 taxonomic families previously documented to be capable of hosting 36 zoonotic pathogens. In these seven markets, the combination of high wildlife volumes, high risk taxa for zoonoses and poor biosafety increases the potential for pathogen presence and transmission. To examine the potential conservation impact of trade in markets, we assessed the status of 33,752 animals observed during 375 visits to 93 markets, under the Lao PDR Wildlife and Aquatic Law. We observed 6,452 animals listed by Lao PDR as near extinct or threatened with extinction. The combined risks of wildlife trade in Lao PDR to human health and biodiversity highlight the need for a multi-sector approach to effectively protect public health, economic interests and biodiversity.

Toward a quantification of risks at the nexus of conservation and health: The case of bushmeat markets in Lao PDR

“…• High contact rates between consumers and bushmeat add to the transmission risk. Wildlife trade and the consumption of wild meat (or "bushmeat") have increasingly been scrutinized for their role in zoonotic pathogen emergence into human populations (Chomel et al, 2007;Karesh et al, 2005;Kilonzo et al, 2013;Swift et al, 2007;Wolfe et al, 2005;Greatorex et al, 2016). There is growing evidence for the presence of zoonotic pathogens in traded and consumed bushmeat (Kilonzo et al, 2013;Kurpiers et al, 2016;Schoder et al, 2015;Smith et al, 2012), and pathogen spillovers into humans have repeatedly occurred as a result of wild meat consumption (Calattini et al, 2007;Kalish et al, 2005;Mouinga-Ondeme et al, 2012;Wolfe et al, 2004).…”

“…In this manuscript, we broadly define the term "consumer" as any market visitor who shows interest in, comes in contact with, purchases, or actually consumes bushmeat. Consumer surveys were conducted in 13 markets previously identified as hotspots for wildlife trade (Greatorex et al, 2016) or more recently discovered as having high volumes of bushmeat during routine monitoring of markets (unpublished data). Between October 2016 and January 2017, each market was visited twice during periods of high attendance by consumers, based on preliminary observations (Greatorex et al, 2016).…”

“…Consumer surveys were conducted in 13 markets previously identified as hotspots for wildlife trade (Greatorex et al, 2016) or more recently discovered as having high volumes of bushmeat during routine monitoring of markets (unpublished data). Between October 2016 and January 2017, each market was visited twice during periods of high attendance by consumers, based on preliminary observations (Greatorex et al, 2016). Observers were posted at strategic locations in each market that allowed observation of market consumers approaching stalls or purchasing bushmeat.…”

“…clients) and purchased animals per species. Based on these counts, the total amount of purchased biomass per species was estimated using previously published average weight of each species (Greatorex et al, 2016). Based on these total amounts of observed purchased meat, we estimated the yearly total volume and retail value for an average market.…”

“…We considered an average market to include five stalls and about 4 h of peak activity per day (comparable to activity levels when observations were carried out) and to be open daily (unpublished data), for a yearly total of 7300 stall-hours. The retail value was calculated based on published average value for each species (Greatorex et al, 2016). As a proxy for exposure of wildlife consumers to bushmeat, we estimated distributions of the quantity of purchased wildlife per consumer and per purchase.…”