More common infections in travelers are gastrointestinal infections (including acute bacterial diarrhea and amebic disease), typhoid fever, and malaria. Chronic and latent infections in immigrants (or long-term residents) include tuberculosis, cysticercosis, visceral leishmaniasis, lymphatic filariasis, echinococcosis, and intestinal helminths. Primary varicella may be seen in adults, as childhood infection is less common in tropical areas.
Vector-borne infections: Malaria is widespread in areas at altitudes lower than 2000 meters and is found in the Terai and Hill districts of Nepal at altitudes lower than 1200 meters. Dengue fever has caused epidemics in all these countries except Nepal. Japanese encephalitis transmission occurs widely in lowland areas of the region (except for Afghanistan). Severe outbreaks occurred in India in 2005. Transmission is seasonal. Focal areas of transmission of visceral leishmaniasis are present in rural India, Pakistan, Nepal, and Bangladesh. Major epidemics of visceral leishmaniasis have occurred in eastern India (especially Assam and Bihar states). Cutaneous leishmaniasis is present in Afghanistan, (where it has infected US troops); India; and Pakistan. Lymphatic filariasis is endemic in large areas of India, Sri Lanka, and Bangladesh. Other vector-borne infections include scrub typhus, murine typhus, epidemic typhus (in remote, cooler areas), relapsing fever, sandfly fever, spotted fever due to R. conorii (especially in India), Kyasanur Forest disease (tick-borne; Karnataka State, India, and Pakistan), and Crimean-Congo hemorrhagic fever* (in Pakistan and Afghanistan). In 2005-2006, an outbreak of chikungunya affected thousands of persons in India.
Food- and water-borne infections: Hepatitis A is widespread, and risk to travelers is high. Large outbreaks of hepatitis E have occurred in Bangladesh, India, Nepal, and Pakistan. Typhoid and paratyphoid fever (increasingly resistant to multiple antimicrobial agents) occur sporadically and in outbreaks and can affect travelers to the region. Amebic infections are common and can cause liver abscesses. Indigenous wild polio was present in in 2005-2006 in India, Pakistan, and Afghanistan; cases from Bangladesh and Nepal were confirmed in 2005-2006. Cyclospora infections have been reported, especially from Nepal. Cholera outbreaks have occurred frequently in the region, especially in Bangladesh and India. Cysticercosis is found, especially in India. Paragonimiasis is endemic in India (Manipur province). Gnathostomiasis has caused sporadic cases and outbreaks.
Airborne and person-to-person: The annual incidence rates of tuberculosis per 100,000 population are estimated to be higher than 300 in Afghanistan and 100-300 in most of the rest of the region. Measles occurs in the region and can be a source of infection for unvaccinated travelers.
Sexually transmitted and blood-borne infections: The prevalence of HIV in adults is less than 1% in most of the region but is rising rapidly in some populations in India (seroprevalence higher than 5% in some antenatal clinics). The prevalence of chronic infection with hepatitis B is 2%-7% in most of the region.
Zoonotic infections: Rabies is common in the region and poses a risk to travelers. Q fever* is widespread. Anthrax* is endemic in much of the region, and cases occur sporadically. Plague* is endemic in India, and outbreaks have occurred. Echinococcosis* is highly endemic in focal rural areas. An outbreak of Nipah virus (encephalitis) occurred in Bangladesh in early 2004, and person-to-person spread may have occurred. Macaques throughout the region are infected with B virus (Herpes).
Highly pathogenic avian influenza (H5N1) has been found in poultry populations in India and Pakistan.
Soil- and water-associated infections: Leptospirosis* is common, especially in tropical areas.
Other hazards: There may be a risk for snake bites, injury from motor vehicle accidents, and injury related to ongoing conflicts. Screening of blood before transfusion is inadequate in many hospitals.