Positioning zoonotic disease research in forced migration: A systematic literature review of theoretical frameworks and approaches

Comparative trends of brucellosis serological testing and confirmed brucellosis cases suggest inappropriate prescription habits

BACKGROUND

Brucellosis is a zoonosis endemic to specific geographical regions. In first line laboratories, diagnosis is made by blood culture or Rose Bengal (RB) serology.

METHODS

We compare brucellosis testing between 2012-2021 at two university hospitals in Brussels, Belgium with concomitant national confirmed cases and institutional cases.

RESULTS

RB testing increased from 30 to 211 tests/year between 2012-2021. A total of fifty-two national brucellosis cases were notified during the study period, of which fifteen cases in Brussels. No trend was noted nationally or regionally. Epidemiological data indicated travel to endemic regions, confirmed by strain testing. Institutional cases all showed symptomatic presentations with positive travel histories.

CONCLUSIONS

Serologic testing inappropriately increases yearly, while annual imported brucellosis cases remain rare, and have positive travel histories and are symptomatic. We therefore support current recommendations of limiting RB testing to symptomatic patients at risk of exposure, meaning predominantly positive recent travel history.

Status of zoonotic disease research in refugees, asylum seekers and internally displaced people, globally: A scoping review of forty clinically important zoonotic pathogens

BACKGROUND

At the end of 2022, there were over 108 million forcibly displaced people globally, including refugees, asylum seekers (AS) and internally displaced people (IDPs). Forced migration increases the risk of infectious disease transmission, and zoonotic pathogens account for 61% of emerging and re-emerging infectious diseases. Zoonoses create a high burden of disease and have the potential to cause large-scale outbreaks. This scoping review aimed to assess the state of research on a range of clinically relevant zoonotic pathogens in displaced populations in order to identify the gaps in literature and guide future research.

METHODOLOGY / PRINCIPAL FINDINGS

Literature was systematically searched to identify original research related to 40 selected zoonotic pathogens of interest in refugees, AS and IDPs. We included only peer-reviewed original research in English, with no publication date restrictions. Demographic data, migration pathways, health factors, associated outbreaks, predictive factors and preventative measures were extracted and synthesized. We identified 4,295 articles, of which 347 were included; dates of publications ranged from 1937 to 2022. Refugees were the most common population investigated (75%). Migration pathways of displaced populations increased over time towards a more complex web, involving migration in dual directions. The most frequent pathogen investigated was Schistosoma spp. (n = 99 articles). Disease outbreaks were reported in 46 publications (13.3%), with viruses being the most commonly reported pathogen type. Limited access to hygiene/sanitation, crowding and refugee status were the most commonly discussed predictors of infection. Vaccination/prophylaxis drug administration, surveillance/screening and improved hygiene/sanitation were the most commonly discussed preventative measures.

CONCLUSIONS / SIGNIFICANCE

The current research on zoonoses in displaced populations displays gaps in the spectrum of pathogens studied, as well as in the (sub)populations investigated. Future studies should be more inclusive of One Health approaches to adequately investigate the impact of zoonotic pathogens and identify transmission pathways as a basis for designing interventions for displaced populations.

Building a pathway to One Health surveillance and response in Asian countries

To detect and respond to emerging diseases more effectively, an integrated surveillance strategy needs to be applied to both human and animal health. Current programs in Asian countries operate separately for the two sectors and are principally concerned with detection of events that represent a short-term disease threat. It is not realistic to either invest only in efforts to detect emerging diseases, or to rely solely on event-based surveillance. A comprehensive strategy is needed, concurrently investigating and managing endemic zoonoses, studying evolving diseases which change their character and importance due to influences such as demographic and climatic change, and enhancing understanding of factors which are likely to influence the emergence of new pathogens. This requires utilisation of additional investigation tools that have become available in recent years but are not yet being used to full effect. As yet there is no fully formed blueprint that can be applied in Asian countries. Hence a three-step pathway is proposed to move towards the goal of comprehensive One Health disease surveillance and response.

Toward One Health: a spatial indicator system to model the facilitation of the spread of zoonotic diseases

Recurrent outbreaks of zoonotic infectious diseases highlight the importance of considering the interconnections between human, animal, and environmental health in disease prevention and control. This has given rise to the concept of One Health, which recognizes the interconnectedness of between human and animal health within their ecosystems. As a contribution to the One Health approach, this study aims to develop an indicator system to model the facilitation of the spread of zoonotic diseases. Initially, a literature review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement to identify relevant indicators related to One Health. The selected indicators focused on demographics, socioeconomic aspects, interactions between animal and human populations and water bodies, as well as environmental conditions related to air quality and climate. These indicators were characterized using values obtained from the literature or calculated through distance analysis, geoprocessing tasks, and other methods. Subsequently, Multi-Criteria Decision-Making (MCDM) techniques, specifically the Entropy and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) methods, were utilized to combine the indicators and create a composite metric for assessing the spread of zoonotic diseases. The final indicators selected were then tested against recorded zoonoses in the Valencian Community (Spain) for 2021, and a strong positive correlation was identified. Therefore, the proposed indicator system can be valuable in guiding the development of planning strategies that align with the One Health principles. Based on the results achieved, such strategies may prioritize the preservation of natural landscape features to mitigate habitat encroachment, protect land and water resources, and attenuate extreme atmospheric conditions.

Effects of migration rates and vaccination on the spread of yellow fever in Latin American communities

Objective

To assess how relevant the flow of people between communities is, compared to vaccination and type of vector, on the spread and potential outbreaks of yellow fever in a disease-free host community.

Methods

Using a SEIRV-SEI model for humans and vectors, we applied numerical simulations to the scenarios: (1) migration from an endemic community to a disease-free host community, comparing the performance of Haemagogus janthinomys and Aedes aegypti as vectors; (2) migration through a transit community located on a migratory route, where the disease is endemic, to a disease-free one; and (3) effects of different vaccination rates in the host community, considering the vaccination of migrants upon arrival.

Results

Results show no remarkable differences between scenarios 1 and 2. The type of vector and vaccination coverage in the host community are more relevant for the occurrence of outbreaks than migration rates, with H. janthinomys being more effective than A. aegypti.

Conclusions

With vaccination being more determinant for a potential outbreak than migration rates, vaccinating migrants on arrival may be one of the most effective measures against yellow fever. Furthermore, H. janthinomys is a more competent vector than A. aegypti at similar densities, but the presence of A. aegypti is a warning to maintain vaccination above recommended levels.

Migrant health during public health emergencies: The Ebola crisis in Uganda

The Ebola virus diseases (EVD) declared in Uganda in September 22, 2022, has spread to seven districts by early November, with a total of 131 confirmed cases and 48 deaths. Public health emergency response in Uganda deserves a specific and tailored approach due to the current population composition, which accounts to around 1.4 million refugees and asylum seekers. Indeed, Uganda is a potential example of how increased international connectivity has resulted in forced migration with profound impacts on global health. In consideration of the vulnerability of refugees and migrants due to poor living, housing, and working conditions, inclusive policies are even more critical during public health emergencies. Inclusivity lessons learned from COVID-19 in several settings, such as access to treatment and vaccination for all individuals regardless of nationality, residence, and legal status, would be critical to ensure wellbeing of migrants, refugees and host communities.

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

BACKGROUND

It remains unclear how human and animal displacement impacts zoonotic disease risk with little contextualized primary data available. This study investigates zoonotic disease dynamics in populations regularly displaced due to slow onset disasters and annual monsoons in the Indus Delta in Sindh province in southeast Pakistan.

METHODS

Using a case study methodology, semi-structured key informant interviews and focus group discussions with 35 participants, as well as observational studies were conducted in seven communities in Thatta district.

RESULTS

Key factors affecting zoonotic disease dynamics in environmental displacement in Thatta identified in the study include disasters and loss of forage, a lack of veterinary and healthcare access, and socio-economic status. Animal and human health are an important consideration in displacement disrupting communities and livelihoods, affecting safety, health, and food security. Displacement results in a poverty spiral whereby the displaced find themselves at continuous peril from poverty and disaster, with zoonotic disease dynamics shifting based on environmental changes, and an expectation of future movement and loss.

CONCLUSION

The precarious conditions generated through the disruption of communities and livelihoods makes environmentally displaced populations vulnerable to zoonotic disease. To prevent further displacement and disease, broader political economy issues need to be addressed, and comprehensive assistance provided to support sustainable livelihoods.