Some countries, such as South Africa, or Thailand have very different infectious disease-related epidemiology to Europe and North America. Exposure to diseases without having built up natural immunity can be a hazard for weakened individuals, specifically with respect to gastrointestinal diseases (e.g. hepatitis A, amoebic dysentery, paratyphoid) which could weaken progress and expose the patient to mosquito-transmitted diseases, influenza, and tuberculosis. However, because in poor tropical nations diseases run the gamut, doctors seem to be more open to the possibility of considering any infectious disease, including HIV, TB, and typhoid, while there are cases in the West where patients were consistently misdiagnosed for years because such diseases are perceived to be "rare" in the West.