Identifying the research gap of zoonotic disease in displacement: a systematic review

Abstract

Background Outbreaks of zoonotic diseases that transmit between animals and humans, against a backdrop of increasing levels of forced migration, present a major challenge to global public health. This review provides an overview of the currently available evidence of how displacement may affect zoonotic disease and pathogen transmission, with the aim to better understand how to protect health and resilience of displaced and host populations. Methods A systematic review was conducted aligned with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines. Between December 2019 - February 2020, PubMed, Web of Science, PLoS, ProQuest, Science Direct and JSTOR were searched for literature. Studies were included based on a focus on zoonotic disease risks in displacement and/or humanitarian emergencies, and relevance in terms of livestock dependency of the displaced populations. Evidence was synthesised in form of a table and thematic analysis. Results Of all records, 78 papers were selected for inclusion. Among the included studies, the majority were based on secondary data, including literature reviews (n=43) and case studies (n=5), while the majority of papers covered wide geographical areas such as the Global South (n=17) and Africa (n=20). The review shows significant gaps in the literature, which is specifically lacking primary data on zoonotic diseases in displacement. Risk factors for the transmission of zoonoses in displacement are based on generic infectious disease risks, which include the loss of health services, increased population density, changes in environment, reduced quality of living conditions and socio-economic factors. Regardless of the presence of these disease drivers during forced migration however, there is little evidence of large-scale zoonotic disease outbreaks linked directly to livestock in displacement. Conclusion Due to the lack of primary research, the complex interlinkages of factors affecting zoonotic pathogen transmission in displacement remain unclear. While the presence of animals may increase the burden of zoonotic pathogens, maintaining access to livestock may improve livelihoods, nutrition and mental health, with the potential to reduce people’s vulnerability to disease. Further primary interdisciplinary and multi-sectoral research is urgently required to address the evidence gaps identified in this review to support policy and program development.

Zoonoses in the margins: environmental displacement and health outcomes in the Indus Delta

“…Respondents discussed these in response to the semi-structured interview questions, which served both to understand the displacement context and potential areas of zoonotic disease risk and vulnerability. Zoonotic disease dynamics are influenced by complex and interlinked drivers; identified factors for zoonotic disease risks include environmental changes, including through disaster, socio-economic profiles, living conditions and access to (veterinary) health services [9] The Jati Baloch communities settled on public 'waste' (JB2a) land between 1960 and 2000, moving inland as a result of sea intrusion and coastal erosion. Ongoing environmental degradation continues to threaten their current locations, while heavy monsoon rains and cyclones regularly cause floods and an increase in mosquitoes.…”

“…Fishing requires significant and recurring investment in the maintenance of boats, fishing nets and other equipment however, forcing many fishers to obtain loans, which are difficult to repay as profits are limited by commissions charged by middlemen and auctioneers [14]. Karrar describes fishing therefore as a 'credit driven industry with endless cycles of borrowing and repayment' , in itself a form of feudalism similar to the landholding system common across the rest of the province [14], and causing a deterioration in people's socio-economic status, thereby in turn impacting health [9].…”

“…During disasters, disease risks are further influenced by ecological conditions, malnutrition, and overcrowding [7]. Subsequent displacement poses a challenge to the prevention and control of zoonotic disease [8], and is considered to increase zoonotic disease risk, as living conditions deteriorate and animals and humans move into new pathogen and vector environments, however, there is little contextualized primary data available on whether zoonotic disease burden in fact increases during displacement [9]. This study therefore aims to provide better insight in what I define as zoonotic disease 'dynamics' , allowing for both increase and decrease in zoonotic disease vulnerabilities and risks, in displaced populations in the Indus Delta in Sindh province in southeast Pakistan.…”

EIDs and the Intersectional Health/Livelihoods Paradox in the Rural Global South

“…However, exposure to infection is high after rainfall when herders and animals are concentrated to capitalise on good grazing and women manage young and sick animals exposing them to disease (Dzingirai et al, 2016). In the case of refugee camps, Braam, Jephcott, and Wood (2021) discuss livestock bans in response to fears herds grazed amongst host communities' livestock or wildlife habitat increase the risk of disease spread. Camps are often established on land with little vegetation and poor agriculture leading to malnutrition, therefore the loss of animals can undermine capacity for livelihood rehabilitation, nutrition, and psychosocial health increasing vulnerability to disease.…”

One Health Paradigm to Confront Zoonotic Health Threats: A Pakistan Prospective

“…The close association of humans and their livestock is linked to the transmission of zoonotic pathogens ( Kilpatrick and Randolph, 2012 ; Suk et al, 2014 ), and these risks are elevated in areas where animals and humans share living areas ( Nieto et al, 2012 ; Owczarczak-Garstecka, 2018 ) and those with inadequate sanitation facilities ( Gayer et al, 2007 ; Warraich et al, 2011 ). When a disease has become established in a human population ( Paterson et al, 2018 ; Braam et al, 2021 ), sedentary conditions in camps and informal settlements increase the risk of zoonotic pathogen transmission and population size and density affect a pathogen’s ability to infect susceptible hosts ( Brooker et al, 2004 ; Hammer et al, 2018 ). Strengthening the standards for improving hygiene and sanitation in local food markets will decrease the risk of zoonotic disease transmission.…”