Geographical Pattern of Infectious Diseases and Infection Prevention for Travellers

Abstract

Infectious diseases are transmitted either directly from person to person via direct contact or droplet exposure, or indirectly through a vector organism (mosquito or tick) or a non-biological physical vehicle (soil or water). Vector-borne infectious diseases are highly influenced by climate factors such as temperature, precipitation, altitude, sunshine duration, and wind. Therefore, climate change is a major threat for the emergence and re-emergence of infectious diseases, e.g. re-emergence of dengue fever in some parts of southern Europe. The natural reservoirs of infectious diseases are either humans (anthroponoses) or animals (zoonoses). Population movement due to travel or civil unrest risks introducing non-immune populations to regions that are endemic for certain infectious diseases. By contrast, global trade contributes to the movement of animals or arthropods across the world and this poses a major risk for introducing infectious diseases to previously non-endemic settings, e.g. rats on board commercial ships and the global spread of hantaviruses; international trade in used car tyres and the risk of introducing flavivirus-infected mosquitoes into non-endemic settings; and the contribution of migratory birds to the introduction and the spread of West Nile virus in the United States. The unprecedented growth of international travel facilitates the swift movement of pathogens by travellers from one region to another. The main determinants of travel-related infections are destination country, activities undertaken during travel, and pre-existing morbidities. Therefore, the pre-travel consultation aims to assess potential health hazards associated with the trip, give advice on appropriate preventative measures, and educate the traveller about their own health. Attitudes towards seeking pre-travel health advice vary by the type of traveller. For example, those visiting friends and relatives (VFRs) in their country of origin are less likely to seek pre-travel health advice compared to tourists and therefore stand a higher chance of presenting with preventable infections such as malaria. The key aspects of a pre-travel consultation include: ● comprehensive risk assessment based on the demographic and clinical background of the traveller as well as the region of travel and itinerary.