Perception of health risks in Lao market vendors

Consumer knowledge, attitudes, and behaviour regarding food safety - A perspective from Laos

Primary research data on food chain safety at consumer level is needed to help policymakers to decrease the risk of foodborne infections in the Lao People's Democratic Republic. Therefore, the objectives of this study are to 1) determine Lao people's food safety knowledge, attitudes, and intentions and identify the most influential factors that shape their food safety behaviour, and 2) to support the government in the development of more efficient risk communication programmes. A paper-based consumer survey was implemented to collect quantitative data on the selected topics about Laotian consumers, as well as on the equipment of households regarding the conditions and tools necessary for safe food preparation and storage. A model was developed based on the extended Theory of Planned Behaviour (TPB), and partial least squares structural equation modelling (PLS-SEM) was applied to analyse the factors that affect food safety behaviour. The elements of Knowledge and Perceived Behavioural Control positively influence behaviours, such as using separate chopping boards for raw and ready-to-eat foods. According to the model, only 10 % of the Intentions would be translated into Behaviours, which gap can be explained by the lack of a hygienic environment. Although the survey indicated that Laotian people intend to follow food safety guidelines, participants felt they lacked sufficient knowledge. This perception was validated by the knowledge test and behavioural part of the study. In the light of these findings, it is essential to raise awareness and promote food safety knowledge and interventions, such as enhancing food safety education in childhood. This would help to facilitate and encourage adopting safe practices to improve overall food safety at the consumer level, delivering positive impacts also to the food business sector.

Human-animal entanglements in bushmeat trading in Sierra Leone: An ethnographic assessment of a potential zoonotic interface

'Bushmeat' markets are often portrayed as chaotic spaces where exotic wild animals are sold. They are hypothesized to be important sites for zoonotic disease transmission, given the prolonged and intense nature of the cross-species encounters that occur within them. Whilst such markets have received some attention from researchers, rich qualitative descriptions of everyday practices in these markets are rare. Depictions of wild animal markets as sites for potential viral amplification often rely on exoticizing assumptions and narratives rather than actual evidence, and in some cases are based more on ideology than on science. We provide an in-depth ethnographic account of two bushmeat markets in Bo, Sierra Leone. Our analysis goes beyond common assumptions that zoonotic risk is located solely in the knowledge and behaviours of traders. Our account sheds light on the modes of touch, closeness and contact that shape this hypothesised zoonotic interface, outlining the possible risks to different people who use and spend time in the market. We found that inadequate infrastructure and sanitation facilities created risks of zoonotic disease transmission for diverse actors including traders, customers, children, and the wider public. Butchering and trading practices frequently resulted in people directly and indirectly encountering animal fluids. We also discuss how public health management of these markets focused on individual behaviours rather than on improving conditions. Urgent sanitary reform and infrastructure upgrades in these sites that support the economic needs of traders could encourage voluntary compliance with biosafety measures amongst traders seeking to balance responsibilities to family and public health. Our study reveals the value of moving beyond exoticized narratives about bushmeat markets to yield situated insights for reducing risk at this interface.

Longitudinal comparison of bacterial pathogen seropositivity among wet market vendors in the Lao People's Democratic Republic

Wild animal trade for human consumption is a global issue, involving complex interactions between economics, culture, food security and conservation. Whilst being a biodiversity issue, it is also a major public health concern, with recent epidemics and pandemics of zoonotic pathogens linked to interactions with wildlife. At three time points, between March 2017 and June 2018, a longitudinal sero-survey of 150 market vendors from three wet markets in Laos (selling vegetables, domestic animal meat and/or wildlife meat) was conducted to determine if vendors had been differentially exposed to three endemic bacterial pathogens - Orientia tsutsugamushi, Rickettsia typhi, and Leptospira spp. A total of 367 serum samples were tested by IgG enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assay (IFA, for scrub typhus group (STG) and typhus group (TG) only). Among vendors, 32.7% were IgG-positive for at least one pathogen, 13.3% sero-converted during the study. Multi-season occupancy modelling for STG indicated a significantly higher prevalence of STG IgG in vegetable vendors (27.3%) and wildlife vendors (28.4%) than in domestic animal meat vendors (6.9 %, p=0.05), and higher in Phonsavanh market (OR=9.6, p=0.03) compared to Lak Sao and Salavan markets. Estimated mean incidence was 57 cases per 10,000 per 7.5-month period. For TG, vendor age had a significant effect on prevalence (OR=1.04, p=0.006), estimated mean incidence was 64 cases per 10,000 per season (7.5-month period). Despite individuals selling domestic meat having a higher prevalence of Leptospira infections than those that did not (11.6% versus 4.5%), the difference was not significant. Whilst this study has a number of limitations, including vendors changing what food types they sold and no investigation of exposure outside of markets, the finding that the risk of exposure of vendors to zoonotic pathogens may be associated with types of food sold for human consumption warrants further investigation.

A strategy to assess spillover risk of bat SARS-related coronaviruses in Southeast Asia

Emerging diseases caused by coronaviruses of likely bat origin (e.g., SARS, MERS, SADS, COVID-19) have disrupted global health and economies for two decades. Evidence suggests that some bat SARS-related coronaviruses (SARSr-CoVs) could infect people directly, and that their spillover is more frequent than previously recognized. Each zoonotic spillover of a novel virus represents an opportunity for evolutionary adaptation and further spread; therefore, quantifying the extent of this spillover may help target prevention programs. We derive current range distributions for known bat SARSr-CoV hosts and quantify their overlap with human populations. We then use probabilistic risk assessment and data on human-bat contact, human viral seroprevalence, and antibody duration to estimate that a median of 66,280 people (95% CI: 65,351–67,131) are infected with SARSr-CoVs annually in Southeast Asia. These data on the geography and scale of spillover can be used to target surveillance and prevention programs for potential future bat-CoV emergence.

Coronaviruses may spill over from bats to humans. This study uses epidemiological data, species distribution models, and probabilistic risk assessment to map overlap among people and SARSr-CoV bat hosts and estimate how many people are infected with bat-origin SARSr-CoVs in Southeast Asia annually.

Virome characterization of game animals in China reveals a spectrum of emerging pathogens

Game animals are wildlife species traded and consumed as food and are potential reservoirs for SARS-CoV and SARS-CoV-2. We performed a meta-transcriptomic analysis of 1,941 game animals, representing 18 species and five mammalian orders, sampled across China. From this, we identified 102 mammalian-infecting viruses, with 65 described for the first time. Twenty-one viruses were considered as potentially high risk to humans and domestic animals. Civets (Paguma larvata) carried the highest number of potentially high-risk viruses. We inferred the transmission of bat-associated coronavirus from bats to civets, as well as cross-species jumps of coronaviruses from bats to hedgehogs, from birds to porcupines, and from dogs to raccoon dogs. Of note, we identified avian Influenza A virus H9N2 in civets and Asian badgers, with the latter displaying respiratory symptoms, as well as cases of likely human-to-wildlife virus transmission. These data highlight the importance of game animals as potential drivers of disease emergence.

Public and health professional epidemic risk perceptions in countries that are highly vulnerable to epidemics: a systematic review

Background

Risk communication interventions during epidemics aim to modify risk perceptions to achieve rapid shifts in population health behaviours. Exposure to frequent and often concurrent epidemics may influence how the public and health professionals perceive and respond to epidemic risks. This review aimed to systematically examine the evidence on risk perceptions of epidemic-prone diseases in countries highly vulnerable to epidemics.

Methods

We conducted a systematic review using PRISMA standards. We included peer-reviewed studies describing or measuring risk perceptions of epidemic-prone diseases among the general adult population or health professionals in 62 countries considered highly vulnerable to epidemics. We searched seven bibliographic databases and applied a four-stage screening and selection process, followed by quality appraisal. We conducted a narrative meta-synthesis and descriptive summary of the evidence, guided by the Social Amplification of Risk Framework.

Results

Fifty-six studies were eligible for the final review. They were conducted in eighteen countries and addressed thirteen epidemic-prone diseases. Forty-five studies were quantitative, six qualitative and five used mixed methods. Forty-one studies described epidemic risk perceptions in the general public and nineteen among health professionals. Perceived severity of epidemic-prone diseases appeared high across public and health professional populations. However, perceived likelihood of acquiring disease varied from low to moderate to high among the general public, and appeared consistently high amongst health professionals. Other occupational groups with high exposure to specific diseases, such as bushmeat handlers, reported even lower perceived likelihood than the general population. Among health professionals, the safety and effectiveness of the work environment and of the broader health system response influenced perceptions. Among the general population, disease severity, familiarity and controllability of diseases were influential factors. However, the evidence on how epidemic risk perceptions are formed or modified in these populations is limited.

Conclusions

The evidence affords some insights into patterns of epidemic risk perception and influencing factors, but inadequately explores what underlies perceptions and their variability, particularly among diseases, populations and over time. Approaches to defining and measuring epidemic risk perceptions are relatively underdeveloped.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40249-021-00927-z.

Bushmeat, wet markets, and the risks of pandemics: Exploring the nexus through systematic review of scientific disclosures

The novel coronavirus (SARS-CoV-2) is the third coronavirus this century to threaten human health, killing more than two million people globally. Like previous coronaviruses, SARS-CoV-2 is suspected to have wildlife origins and was possibly transmitted to humans via wet markets selling bushmeat (aka harvested wild meat). Thus, an interdisciplinary framework is vital to address the nexus between bushmeat, wet markets, and disease. We reviewed the contemporary scientific literature to: (1) assess disease surveillance efforts within the bushmeat trade and wet markets globally by compiling zoonotic health risks based on primarily serological examinations; and (2) gauge perceptions of health risks associated with bushmeat and wet markets. Of the 58 species of bushmeat investigated across 15 countries in the 52 articles that we analyzed,one or more pathogens (totaling 60 genera of pathogens) were reported in 48 species, while no zoonotic pathogens were reported in 10 species based on serology. Burden of disease data was nearly absent from the articles resulting from our Scopus search, and therefore was not included in our analyses. We also found that perceived health risks associated with bushmeat was low, though we could not perform statistical analyses due to the lack of quantitative perception-based studies. After screening the literature, our results showed that the global distribution of reported bushmeat studies were biased towards Africa, revealing data deficiencies across Asia and South America despite the prevalence of the bushmeat trade across the Global South. Studies targeting implications of the bushmeat trade on human health can help address these data deficiencies across Asia and South America. We further illustrate the need to address the nexus between bushmeat, wet markets, and disease to help prevent future outbreaks of zoonotic diseases under the previously proposed "One Health Framework", which integrates human, animal, and environmental health. By tackling these three pillars, we discuss the current policy gaps and recommend suitable measures to prevent future disease outbreaks.

Low seroprevalence of COVID-19 in Lao PDR, late 2020

BACKGROUND

In 2020 Lao PDR had low reported COVID-19 cases but it was unclear whether this masked silent transmission. A seroprevalence study was done August - September 2020 to determine SARS-CoV-2 exposure.

METHODS

Participants were from the general community (n=2433) or healthcare workers (n=666) in five provinces and bat/wildlife contacts (n=74) were from Vientiane province. ELISAs detected anti- SARS-CoV-2 Nucleoprotein (N; n=3173 tested) and Spike (S; n=1417 tested) antibodies. Double-positive samples were checked by IgM/IgG rapid tests. Controls were confirmed COVID-19 cases (n=15) and pre-COVID-19 samples (n=265). Seroprevalence for the general community was weighted to account for complex survey sample design, age and sex.

FINDINGS

In pre-COVID-19 samples, 5·3%, [95% CI=3·1-8·7%] were anti-N antibody single-positive and 1·1% [0·3-3·5%] were anti-S antibody single positive. None were double positive. Anti-N and anti-S antibodies were detected in 5·2% [4·2-6·5%] and 2·1% [1·1-3·9%] of the general community, 2·0% [1·1-3·3%] and 1·4% [0·5-3·7%] of healthcare workers and 20·3% [12·6-31·0%] and 6·8% [2·8-15·3%] of bat/wildlife contacts. 0·1% [0·02-0·3%] were double positive for anti-N and anti-S antibodies (rapid test negative).

INTERPRETATION

We find no evidence for significant SARS-CoV-2 circulation in Lao PDR before September 2020. This likely results from early decisive measures taken by the government, social behavior, and low population density. High anti-N /low anti-S seroprevalence in bat/wildlife contacts may indicate exposure to cross-reactive animal coronaviruses with threat of emerging novel viruses.

FUNDING

Agence Française de Développement. Additional; Institut Pasteur du Laos, Institute Pasteur, Paris and Luxembourg Ministry of Foreign and European Affairs ("PaReCIDS II").

No need to beat around the bushmeat-The role of wildlife trade and conservation initiatives in the emergence of zoonotic diseases

Wildlife species constitute a vast and uncharted reservoir of zoonotic pathogens that can pose a severe threat to global human health. Zoonoses have become increasingly impactful over the past decades, and the expanding trade in wildlife is unarguably among the most significant risk factors for their emergence. Despite several warnings from the academic community about the spillover risks associated with wildlife trade, the ongoing COVID-19 pandemic underlines that current policies on the wildlife industry are deficient. Conservation initiatives, rather than practices that attempt to eradicate zoonotic pathogens or the wild species that harbour them, could play a vital role in preventing the emergence of life-threatening zoonoses. This review explores how wildlife conservation initiatives could effectively reduce the risk of new zoonotic diseases emerging from the wildlife trade by integrating existing literature on zoonotic diseases and risk factors associated with wildlife trade. Conservation should mainly aim at reducing human-wildlife interactions in the wildlife trade by protecting wildlife habitats and providing local communities with alternative protein sources. In addition, conservation should focus on regulating the legal wildlife trade and education about disease transfer and safer hunting and butchering methods. By uniting efforts for wildlife protection and universal concern for preventing zoonotic epidemics, conservation initiatives have the potential to safeguard both biodiversity, animal welfare, and global human health security.

Perception of health risks in Lao market vendors

Wet markets are a critical part of South‐East Asian culture and economy. However, their role in circulation and transmission of both endemic and emerging disease is a source of concern in a region considered a hotspot of disease emergence. In the Lao People's Democratic Republic (Lao PDR, Laos), live and dead wild animals are frequently found in wet markets, despite legislation against the bushmeat trade. This is generally considered to increase the risk of disease transmission and emergence, although whether or not wildlife vendors themselves have indeed increased incidence of zoonotic disease has rarely been assessed. In preparation for a future longitudinal study of market vendors investigating vendors’ exposure to zoonotic pathogens, we conducted a pilot survey of Lao market vendors of wildlife meat, livestock meat and vegetables, to identify demographic characteristics and potential control groups within markets. We also investigated baseline risk perception for infectious diseases among market vendors and assessed the association between risk perception and risk mitigation behaviours. The surveys conducted with 177 vendors revealed similar age, sex, ethnic background and geographical origin between vendor types, but differences in professional background and work history for livestock meat vendors. The perception of disease risk was very low across all vendors, as was the reported use of personal protective equipment, and the two appeared unrelated. Personal risk discounting and assumptions about transmission routes may explain this lack of association. This information will help inform the development of future research, risk communication and risk mitigation policy, especially in the light of the COVID‐19 pandemic.