A new study, Travel-associated Illness Trends and Clusters, 2000-2010, has found that gastric illnesses, skin conditions and fever-causing diseases such as malaria and dengue fever are the most common types of international travel-related illnesses.
A team of tropical and infectious disease specialists evaluated data from 42,173 sick travellers and immigrants seen at 18 GeoSentinel travel medicine clinics between 2007 and 2011, with the aim of the research being to show where the travellers became ill and the types of illnesses acquired in different countries. The travel clinic data showed that: more than half of international travellers to developing countries become ill during their trip; around eight per cent sought medical care while they were away or on their return; and that the places with the highest risk for contracting a travel-related illness included Asia (a 32-per-cent risk), sub-Saharan Africa (a 26.7-per-cent risk) and Latin America/Caribbean (a 19.2-per-cent risk). Gastro-intestinal illness was the most common travel-related condition, affecting one in three travellers. In southeast Asia, sub-Saharan Africa, the Middle East and North Africa, the most common illness were bacterial infections such as Campylobacter, Salmonella and Shigella. Travellers who visited India and neighbouring countries most commonly returned with the water-borne parasite Giardia, the most common symptoms of which were chronic diarrhoea or post-infection irritable bowel syndrome.
The study also showed that malaria accounted for 29 per cent of travellers with a fever-causing illness and Africa and Oceanic countries also accounted for high levels of the disease among travellers. Malaria caused by the malignant P. falciparum parasite, which can result in severe symptoms and death, was the most common among travellers who had visited sub-Saharan Africa. Of those travellers who were infected with dengue fever, 50 per cent had visited southeast Asia, 17 per cent had been to south-central Asia, between nine and 10 per cent had travelled in Central America, South America and the Caribbean, while five per cent had visited countries in sub-Saharan Africa. Over the course of the study period, the researchers noted that there was an increase in travellers infected with chikungunya fever.
Dr Karin Leder, head of Travel Medicine and Immigrant Health at the Royal Melbourne Hospital and lead researcher of the study, said the findings reflected both the growth of travel and its changing patterns. The number of patients seeking treatment for post-travel illnesses just at the GeoSentinel clinics rose by five per cent each year during the past decade, and the study did not include travellers who returned from holiday and saw their usual general practitioner.