Disease Risks and Precautions
in Southeast Asia
The material
provided below is for informational purposes only.
It may not be current, and it should not be considered definitive.
All travelers
should check the Center for Disease Control (CDC) website
for the most current disease risk and disease prevention information.
DISEASES TRANSMITTED BY INSECTS
DISEASES TRANSMITTED THROUGH
FOOD AND WATER
DISEASES TRANSMITTED THROUGH
INTIMATE CONTACT
OTHER DISEASES
SUMMARY OF RECOMMENDATIONS
FOR SOUTHEAST ASIA
COUNTRIES IN REGION
Brunei Darussalam, Cambodia, Indonesia, Lao People's Democratic
Republic (Laos), Malaysia, Burma (Myanmar), Philippines, Singapore,
Thailand, Viet Nam.
GENERAL PRECAUTIONS
Travelers to Southeast Asia may be exposed
to potential diseases from a number of sources. The most frequently
reported illness is traveler's diarrhea, but there are other diseases
which are unique to Southeast Asia or the tropics. These diseases
are transmitted by insects, contaminated food and water, or close
contact with infected people. Specific diseases are discussed
under each of these topical headings. In order to reduce the risk
of infection travelers must (1) protect themselves from insects,
(2) ensure the quality of their food and drinking water, and (3)
be knowledgeable about potential diseases in the region to be
visited. Finally, diseases are not restricted to cleanly defined
geographical areas, i.e. mosquitoes can fly over city or country
borders, therefore, all travelers should protect themselves by
taking the basic preventive precautions.
DISEASES TRANSMITTED BY INSECTS
Many diseases are transmitted through
the bite of infected insects such as mosquitoes, flies, fleas,
ticks, and lice. In general travelers must protect themselves
from insect bites by wearing proper clothing, using bednets, applying
an insect repellent to exposed skin and clothing, and if possible,
avoiding high risk situations, i.e. outdoor activities during
night time hours from dusk to dawn when mosquitoes bite, unscreened
living accommodations, etc. If a mosquito net is unlikely to be
available, consideration should be given to purchasing a portable
mosquito net.
MALARIA
Risk: A risk for malaria exists throughout
the year in all parts of these countries including some urban
areas.
Burma (Myanmar): malaria risk in rural areas only (largely confined
to rural areas not visited by most travelers - most travel to
rural areas is in the daytime hours when there is minimal risk
of exposure).
Cambodia: malaria risk in all areas, except Phnom Penh.
Indonesia: in general, malaria risk in rural areas only (largely
confined to rural areas not visited by most travelers - most travel
to rural areas is in the daytime hours when there is minimal risk
of exposure), except high risk in all areas of Irian Jaya (western
half of the island of New Guinea); no risk in the big cities and
resort areas of Java and Bali.
Lao People's Democratic Republic: malaria risk in all areas, except
no risk in city of Vientiane.
Malaysia: for peninsular Malaysia and Sarawak (NW Borneo) malaria
risk is limited to the rural hinterlands; urban and coastal areas
are malaria free; Sabah (NE Borneo) has malaria throughout.
Philippines: malaria risk in rural areas only, except no risk
in Provinces of Bohol, Catanduanes, Cebu, and Leyte. Malaria transmission
is largely confined to rural areas not visited by most travelers.
(Most travel to rural areas is in the daytime hours when there
is minimal risk of exposure. See specific instructions in the
prevention section below.)
Thailand: Malaria transmission is confined to the forested areas
of its borders with Cambodia, Burma, and Laos. Most travelers
to Thailand are not in malaria risk areas and do not require prophylaxis.
There is no risk of malaria in Bangkok, or the tourist areas of
Ayuthaya, Songkhla, Udorn, Khong-Kaen, Pattaya, Phuket Island,
CoSamet Island, Chieng Mai, and Chiang Rai, including treks out
of Chieng Mai and Chiang Rai. (In Thailand's risk areas, use doxycycline
for malaria prevention. See prevention section below).
Viet Nam: malaria risk in all areas, except the cities of Hanoi
and Ho Chi Minh City. In this region the dominant form of malaria
is P. falciparum (the most dangerous type), which has been reported
to be resistant to the drug chloroquine.
Brunei Darussalam and Singapore: no risk of malaria.
Prevention: Travelers to Cambodia, Indonesia, Lao Peoples' Democratic
Republic, Malaysia, Burma(Myanmar), and Viet Nam at risk for malaria
should takeMEFLOQUINE to prevent malaria.
Travelers to Thailand who overnight in the few areas of risk should
take DOXYCYCLINE. If DOXYCYCLINE is used, there is no need to
take other preventive drugs, such as chloroquine.
In the Philippines, since malaria transmission is largely confined
to the rural areas not visited by most travelers, taking drugs
to prevent malaria is only recommended for travelers who will
have outdoor exposure during evening and nighttime hours in rural
areas. Travelers to the rural areas of the Philippines at risk
of malaria should take one of two drugs to prevent malaria transmission.
If traveling to rural areas other than those listed below, travelers
should take a weekly CHLOROQUINE tablet. Travelers to the rural
areas on the Philippine Islands of Luzon, Basilian, Mindoro, Palawan,
Mindanao, and to Sulu Archipelago should take MEFLOQUINE for prevention
of malaria.
In addition to using drugs to prevent malaria, travelers should
use measures to reduce exposure to malaria-carrying mosquitoes,
and protect themselves from mosquito bites. These mosquitoes bite
mainly during the evening and night, from dusk to dawn.
DENGUE FEVER
Risk: Dengue fever occurs throughout Southeast
Asia with epidemics most recently in Cambodia, Indonesia, Laos,
East and West Malaysia, Burma (Myanmar), Philippines, Singapore,
Thailand, and Viet Nam. The risk of infection is small for most
travelers except during periods of epidemic transmission.
Prevention: There is no vaccine for dengue fever, therefore the
traveler
should avoid mosquito bites. These mosquitoes bite mainly in the
daytime.
JAPANESE ENCEPHALITIS
Risk: Transmission is usually seasonal
(associated with the rainy season). There is a risk for travelers
to rural areas of Southeast Asian countries, especially Burma,
Thailand, Cambodia, Indonesia, Laos, Malaysia, the Philippines,
Thailand, and Viet Nam. The chance that a traveler to Asia will
develop Japanese Encephalitis is extremely small.
Prevention: Vaccination should be considered for persons who plan
long-term residence in rural areas. Travelers who visit rural
farming areas for 4 weeks or more during the transmission season
should consider immunization. Travelers who remain un-immunized
should wear mosquito repellents, sleep under bednets, and bring
insecticidal sprays to use in their sleeping quarters.
YELLOW FEVER
Yellow fever is a viral disease found
in parts of Africa and South America. It is transmitted to humans
by a mosquito bite. Even though there is no risk of becoming infected
while traveling in Southeast Asian countries, a number of these
countries REQUIRE a yellow fever vaccination if a traveler is
coming from areas in AFRICA and SOUTH AMERICA where yellow fever
is found.
If you are ONLY traveling from the United States to a Southeast
Asian country, CDC does not recommend, and you are not required
to have a yellow fever vaccination. However, if your travel plans
include traveling to or from a country in Africa or South America,
you may be required to have a yellow fever vaccination.
OTHER INSECT DISEASES
Risks: Other diseases spread by mosquitoes, sand flies, black
flies, or other insects are prevalent, especially in rural areas.
These diseases include: Filariasis and Chikungunya (mosquito),
leishmaniasis (sandfly), typhus (lice), and Plague (fleas).
PREVENTING INSECT BITE
To reduce mosquito bites travelers should remain in well-screened
areas, use mosquito nets, and wear clothes that cover most of
the body. Travelers should also take insect repellent with them
to use on any exposed areas of the skin. The most effective repellent
is DEET (N,N-diethyl meta-toluamide) an ingredient in most insect
repellents. Travelers should also purchase a flying insect-killing
spray to use in living and sleeping areas during the evening and
night. For greater protection clothing and bednets can be soaked
in or sprayed with PERMETHRIN, which is an insect repellent licensed
for use on clothing. If applied according to the directions, permethrin
will repel insects from clothing for several weeks.
DISEASES TRANSMITTED THROUGH FOOD AND
WATER
Food and waterborne diseases are the number one cause of illness
to travelers and are very common in South East Asia. Traveler's
diarrhea is the most frequent health problem for travelers. It
can be caused by viruses, bacteria, or parasites which are found
universally throughout the region. Transmission is most often
through contaminated food or water. Infections cause diarrhea
and vomiting (typhoid fever, cholera, and parasites), liver damage
(hepatitis), or muscle paralysis (polio).
TYPHOID FEVER
Risk: Travelers to Southeast Asia are
at risk for typhoid fever, especially when traveling to smaller
cities, villages, or rural areas.
Prevention: By drinking only bottled or boiled water and eating
only thoroughly cooked food, a traveler lowers the risk of infection.
Currently available vaccines have been shown to protect 70- 90%
of the recipients. Therefore, even vaccinated travelers should
be cautious in selecting their food and water. Two available vaccines
provide equivalent protection against typhoid fever- oral and
injectable.
Recommendations: CDC recommends a typhoid vaccination for those
travelers who are going off the usual tourist itineraries, traveling
to smaller cities and rural areas, or staying long term, that
is, a traveler for six weeks or more. Typhoid vaccination is not
required for international travel.
CHOLERA
Risk: Cholera cases have been reported
from some of the countries of Southeast Asia. The risk of infection
to the U. S. traveler is low, especially those that are following
the usual tourist itineraries and staying in standard accommodations.
Travelers should consider the vaccine if they have stomach ulcers,
use anti-acid therapy, or if they will be living in less than
sanitary conditions in areas of high cholera activity.
Prevention: Travelers to cholera infected areas should follow
the standard food and water precautions of eating only thoroughly
cooked food, peeling their own fruit, and drinking either boiled
water, bottled carbonated water, or bottled carbonated soft drinks.
Persons with severe cases respond well to simple fluid and electrolyte-replacement
therapy, but medical attention must be sought quickly when cholera
is suspected. The available vaccine is only 50% effective in reducing
the illness, and is not recommended routinely for travelers.
HEPATITIS A
Risk: Travelers are at high risk for Hepatitis
A, especially if travel plans include visiting rural areas and
extensive travel in the countryside, frequent close contact with
local persons, or eating in settings of poor sanitation. A study
has shown that many cases of travel-related hepatitis A occur
in travelers to developing countries with "standard"
itineraries, accommodations, and food consumption behaviors.
Prevention: The virus is inactivated by boiling or cooking to
85 degrees centigrade for one minute, therefore eating thoroughly
cooked foods and drinking only treated water serve as general
precautions. Havrix, the hepatitis A vaccine currently licensed
for use in the U.S., or immune globulin (IG) is recommended before
travel for persons 2 years of age orolder. Hepatitis A vaccine
is preferred for persons who plan to travel repeatedly or reside
for long periods of time in intermediate or high risk areas.
Recommendations: CDC recommends hepatitis A vaccine or IG for
protection against hepatitis A. Immune globulin should be used
for travelers < 2 years of age. Immune globulin is recommended
for persons of all ages who desire only short term protection.
PARASITES
Parasitic infections are acquired by eating
or drinking contaminated food or water, through direct contact
with soil or water containing parasites or their larva, or by
contact with biting insects.
Symptoms and evidence of infection may include, but are not limited
to fever, swollen lymph nodes, rashes or itchy skin, digestive
problems such as abdominal pain or diarrhea, eye problems, and
anemia.
Risk: Travelers to Southeast Asia are at risk of parasitic infections.
There are many types of parasites and infection may occur in several
ways: by eating undercooked meats infected with parasites or their
larva; by eating food or drinking water contaminated with parasites
or their eggs; by contact with soil or water infected with parasites;
or through insect bites. Several types of parasites can penetrate
intact skin and travelers are advised to wear shoes and avoid
swimming, wading, or washing in fresh water.
Prevention: Travelers should eat only thoroughly cooked food,
drink safe water, wear shoes, refrain from swimming in fresh water,
and avoid contact with insects, particularly mosquitoes, biting
flies, gnats, and midges.
DISEASES TRANSMITTED THROUGH INTIMATE
CONTACT WITH PEOPLE
HIV / AIDS
Risk: AIDS is found throughout the region.
In Southeast Asia, heterosexual transmission is now the predominant
mode of transmission, and there are high numbers of HIV-positive
injecting drug users. The risk to a traveler depends on whether
the traveler will be involved in sexual or needle-sharing contact
with a person who is infected with HIV. Receipt of unscreened
blood for transfusion poses a risk for HIV infection.
Prevention: No effective vaccine has been developed for HIV. Travelers
should avoid sexual or needle-sharing contact with a person who
is infected with HIV. If a blood transfusion is necessary, screened
blood should be from an HIV-negative blood donor.
Recommendations: Travelers should avoid activities known to carry
risks for infection with HIV.
HEPATITIS B
Risk: The risk of Hepatitis B virus infection
is high for Southeast Asia. The risk to the individual international
traveler is determined by the extent of: (1) direct contact with
blood or other body fluids, etc.; (2) intimate sexual contact
with an infected person; (3) the duration of travel.
Prevention: The primary prevention consists of either vaccination
and/or reducing intimate contact with those suspected of being
infected. For those travelers expecting to reside in countries
of high risk, as well as all health workers, vaccination is strongly
recommended. Vaccination should
ideally begin 6 months before travel.
Recommendations: CDC recommends vaccination for any of the following
people: any health care worker (medical, dental, or laboratory)
whose activities might result in blood exposure; any traveler
who may have intimate sexual contact with the local population;
any long-term (6 months or more)
traveler, e.g. teachers, who will reside in rural areas or have
daily physical contact with the local population; or any traveler
who is likely to seek either medical, dental, or other treatment
in local facilities during their stay. Hepatitis B vaccination
is not required for travel to any country.
OTHER DISEASES
SCHISTOSOMIASIS
Risk: Schistosomiasis infection is found in some parts of a few
Southeast Asian countries. Cambodia, Indonesia, Laos, Philippines,
and Thailand all have specific areas of potential infection. The
risk is a function of the frequency and degree of contact with
contaminated fresh water for bathing, wading, or swimming.
Prevention: The traveler cannot distinguish between infested and
non-infested water. Therefore, swimming in fresh water in rural
areas should be avoided. Bath water should either be heated to
50 degrees C (122 degrees F) for five minutes or treated with
chlorine or iodine as done for drinking water. If exposed, immediate
and vigorous towel drying or application of rubbing alcohol to
the exposed areas may reduce the risk of infection. Screening
procedures are available for those who suspect infection, and
schistosomiasis is treatable with drugs.
Recommendations: Avoid contact with potentially contaminated water.
RABIES
Risk: For most countries in Southeast
Asia, there is a risk of rabies infection particularly in rural
areas, or in areas where large numbers of dogs are found. Singapore
has reported no rabies cases for at least the past two years.
Prevention: Do not handle any animals! Any animal bite should
receive prompt attention. When wounds are thoroughly cleaned with
large amounts of soap and water, the risk of rabies infection
is reduced. Exposed individuals should receive prompt medical
attention and advice on post-exposure preventive treatment.
Recommendations: There are no requirements for vaccination, but
pre-exposure vaccination is recommended for:
- travelers visiting, for more than 30 days, foreign areas where
rabies is known to exist;
- veterinarians and animal handlers;
- spelunkers; and
- certain laboratory workers.
Pre-exposure vaccination does not nullify the need for post exposure
vaccine, but reduces the number of injections.
SUMMARY OF RECOMMENDATIONS FOR SOUTHEAST
ASIA
Travelers should (1) take appropriate country specific malaria
prevention measures (mefloquine, doxycycline, or chloroquine),
(2) follow precautions to prevent insect bites, (3) pay attention
to the quality of their drinking water and food, (4) have a dose
of Immune Globulin (IG) or the Hepatitis A vaccine, and (5) consider
booster doses of tetanus (Td) and polio (eIPV) vaccines. (6) Depending
on the locations to be visited, planned activities, and health
of the traveler, the following vaccines should be considered:
Hepatitis B, Japanese Encephalitis, Typhoid, Rabies (pre-exposure),
and Cholera. (7) Finally, the normal "childhood" vaccines
should be up-to-date: Measles, Mumps, Rubella (MMR Vaccine); Diphtheria,
Tetanus, Pertussis (DTP Vaccine) [ < 7 years of age], and Polio
vaccine.
Disease risks and precautions