Urban medicine: threats to health of travelers to developing world cities

Travelling to polluted cities: a systematic review on the harm of air pollution on international travellers' health

RATIONALE FOR REVIEW

In 2019, approximately, 1.4 billion people travelled internationally. Many individuals travel to megacities where air pollution concentrations can vary significantly. Short-term exposure to air pollutants can cause morbidity and mortality related to cardiovascular and respiratory disease, with the literature clearly reporting a strong association between short-term exposure to particulate matter ≤2.5 μm and ozone with adverse health outcomes in resident populations. However, limited research has been conducted on the health impacts of short-term exposure to air pollution in individuals who travel internationally. The objective of this systematic review was to review the evidence for the respiratory and cardiovascular health impacts from exposure to air pollution during international travel to polluted cities in adults aged ≥18 years old.

KEY FINDINGS

We searched PubMed, Scopus and EMBASE for studies related to air pollution and the health impacts on international travellers. Of the initially identified 115 articles that fit the search criteria, 6 articles were selected for the final review. All six studies found indications of adverse health impacts of air pollution exposure on international travellers, with most of the changes being reversible upon return to their home country/city. However, none of these studies contained large populations nor investigated vulnerable populations, such as children, elderly or those with pre-existing conditions.

CONCLUSIONS

More research is warranted to clearly understand the impacts of air pollution related changes on travellers' health, especially on vulnerable groups who may be at higher risk of adverse impacts during travel to polluted cities.

Cutaneous Leishmaniasis: The Complexity of Host's Effective Immune Response against a Polymorphic Parasitic Disease

This review is aimed at providing a comprehensive outline of the immune response displayed against cutaneous leishmaniasis (CL), the more common zoonotic infection caused by protozoan parasites of the genus Leishmania. Although of polymorphic clinical presentation, classically CL is characterized by leishmaniotic lesions on the face and extremities of the patients, which can be ulcerative, and even after healing can lead to permanent injuries and disfigurement, affecting significantly their psychological, social, and economic well-being. According a report released by the World Health Organization, the disability-adjusted life years (DALYs) lost due to leishmaniasis are close to 2.4 million, annually there are 1.0–1.5 million new cases of CL, and a numerous population is at risk in the endemic areas. Despite its increasing worldwide incidence, it is one of the so-called neglected tropical diseases. Furthermore, this review provides an overview of the existing knowledge of the host innate and acquired immune response to cutaneous species of Leishmania. The use of animal models and of in vitro studies has improved the understanding of parasite-host interplay and the complexity of immune mechanisms involved. The importance of diagnosis accuracy associated with effective patient management in CL reduction is highlighted. However, the multiple factors involved in CL epizoology associated with the unavailability of vaccines or drugs to prevent infection make difficult to formulate an effective strategy for CL control.

Protecting the health of medical students on international electives in low-resource settings

BACKGROUND

Increasingly, medical students from developed countries are undertaking international medical electives in developing countries. Medical students understand the many benefits of these electives, such as the opportunity to develop clinical skills, to gain insight into global health issues and to travel to interesting regions of the world. However, they may be much less aware of the risk to their health and wellbeing while abroad. Compounding this problem, medical students may not seek advice from travel medicine practitioners and often receive inadequate or no information from their medical school prior to departure.

METHODS

The PubMed database was searched for relevant literature relating to the health of medical elective students. Combinations of the following key words were used as search terms: 'international health elective', 'medical student' and 'health risks'. Articles were restricted to those published in English from 1997 through June 2017. A secondary review of the reference lists of these articles was performed. The grey literature was also searched for relevant material.

RESULTS

This narrative literature review outlines the risks of clinical electives in resource-poor settings which include exposure to infectious illness, trauma, sexual health problems, excessive sun exposure, mental health issues and crime. Medical students may mitigate these health risks by being informed and well prepared for high-risk situations. The authors provide evidence-based travel advice which aims to improve pre-travel preparation and maximize student traveller safety. A safer and more enjoyable elective may be achieved if students follow road safety advice, take personal safety measures, demonstrate cultural awareness, attend to their psychological wellbeing and avoid risk-taking behaviours.

CONCLUSION

This article may benefit global health educators, international elective coordinators and travel medicine practitioners. For students, a comprehensive elective checklist, an inventory of health kit items and useful web-based educational resources are provided to help prepare for electives abroad.

Road Traffic and Other Unintentional Injuries Among Travelers to Developing Countries

Injuries result in nearly 6 million deaths and incur 52 million disability-adjusted life-years annually, making up 15% of the global disease burden. More than 90% of this burden occurs in low- and middle-income countries. Given this burden, it is not unexpected that injuries are the leading cause of death among travelers to low- and middle-income countries, namely, from road traffic crashes and drowning. Therefore, pretravel advice regarding foreseeable dangers and how to avoid them may significantly mitigate injury risk, such as wearing seatbelts, helmets, and personal flotation devices when appropriate; responsibly consuming alcohol; and closely supervising children.

Travel medicine research priorities: establishing an evidence base

BACKGROUND

Travel medicine is the medical subspecialty which promotes healthy and safe travel. Numerous studies have been published that provide evidence for the practice of travel medicine, but gaps exist.

METHODS

The Research Committee of the International Society of Travel Medicine (ISTM) established a Writing Group which reviewed the existing evidence base and identified an initial list of research priorities through an interactive process that included e-mails, phone calls, and smaller meetings. The list was presented to a broader group of travel medicine experts, then was presented and discussed at the Annual ISTM Meeting, and further revised by the Writing Group. Each research question was then subject to literature search to ensure that adequate research had not already been conducted.

RESULTS

Twenty-five research priorities were identified and categorized as intended to inform pre-travel encounters, safety during travel, and post-travel management.

CONCLUSION

We have described the research priorities that will help to expand the evidence base in travel medicine. This discussion of research priorities serves to highlight the commitment that the ISTM has in promoting quality travel-related research.

Urban malaria risk in sub-Saharan Africa: Where is the evidence?

It is essential that the precautions that are advisable for travel in sub-Saharan Africa, including antimalarial prophylaxis, are supported by evidence. Sub-Saharan Africa accounts for 90% of global malaria cases and the more serious falciparum form predominates. The risk of malaria transmission is qualitatively much greater in rural than urban areas. However, there is little quantitative data on the risk in urban areas on which to base a risk assessment. Rapid urban population growth and trends of tourism to urban-only (rather than rural) areas both support the need to focus attention on the level of risk in malaria endemic African cities. There is evidence in urban settings that the reduced intensity of malaria transmission is due to a decline in the level of parasitism in the local population and reduced anophelism. The most useful evidence for an urban risk assessment is the entomological inoculation rate (EIR) which is generally below 30 infective bites per person per year. Transmission is acknowledged to be much lower in central urban areas compared with peri-urban areas or rural areas. Transmission is local and focal because the anopheles mosquito has a limited flight range of several kilometres. The risk assessment should examine nocturnal activities outside an air-conditioned environment (because the anopheline mosquito only bites between dusk and dawn) and the level of adherence to accompanying protective measures. Several studies have noted the protection air-conditioning provides against malaria. Evidence of low occupational risk for airline crew, unprotected by prophylaxis, from brief layovers of several nights in quality hotels in 8 endemic cities is explored. A literature search examines the evidence of environmental surveys and entomological inoculation rates. The limitations of the available data are discussed, including the highly focal nature of malaria transmission.