World Diseases

The degree of risk from any infectious disease is assessed by considering the foreign nature of these infections to a given population, their severity, and the probability of being affected by the diseases present. The list of diseases found in a specific country does not necessarily represent the total disease burden experienced by the local population. The risk to an individual traveler varies considerably by the specific location, the visit duration, the type of activities undertaken, the type of accommodations used, the time of year, and many other factors. A consultation with a travel medicine physician is recommended to evaluate individual risk and to determine appropriate preventive measures, including vaccination.

CountryReports groups infectious diseases into six exposure categories that describe the principal route by which people acquire each illness. These categories are food or waterborne, vectorborne, water contact, aerosolized dust or soil contact, respiratory, and animal contact. The sequence of categories listed in individual country entries varies according to local conditions, with the highest-risk exposure category presented first. Within each category, diseases are listed in typical descending order of risk. At the end of the page a seventh section summarizes the noncommunicable diseases that now account for roughly seventy-one percent of all deaths worldwide, along with notable additional infections that do not fit cleanly into the travel-medicine framework.

Global health organizations measure disease burden through two principal frameworks. The first is mortality, which counts the number of deaths attributable to specific conditions. The second is the disability-adjusted life year, or DALY, which combines years of life lost to premature death with years lived with disability. Together these metrics underpin the Global Burden of Disease study coordinated by the Institute for Health Metrics and Evaluation at the University of Washington and the Global Health Estimates produced by the World Health Organization. Both sources agree that noncommunicable diseases now dominate the global burden, that cardiovascular disease is the leading single cause of death, and that a short list of infections, principally lower respiratory infection, tuberculosis, HIV, malaria, and diarrheal disease, continues to cause a disproportionate share of communicable-disease mortality in low-income countries.

The picture of global health is not static. Resistance to antibiotics and antimalarials is rising. Mosquito vectors are expanding their range as a consequence of land-use change and a warming climate. Zoonotic spillover events, in which a pathogen crosses from an animal reservoir into the human population, continue to produce outbreaks and occasional pandemics. The COVID-19 pandemic that began in late 2019, the 2022 mpox public health emergency of international concern, and the continuing H5N1 avian influenza panzootic all illustrate the speed at which the global disease landscape can change. The information on this page reflects the most recent available estimates but should be read alongside the continually updated country profiles and the current notices published by the World Health Organization.