The Zika virus is a mosquito-borne illness transmitted primarily by the bite of infected Aedes mosquitoes, the same species responsible for spreading dengue and chikungunya. Zika has been identified in numerous countries, and its circulation in popular travel destinations makes it a subject of consideration for international visitors.
Zika Virus Presence and Risk in Thailand
Zika virus is endemic in Thailand, meaning it consistently circulates at low levels. This is different from regions that have experienced large, widespread outbreaks. Health organizations, including the U.S. Centers for Disease Control and Prevention (CDC), acknowledge this status and do not classify Thailand as having a current outbreak.
For the average traveler, the risk of contracting Zika in Thailand is low, though cases in returning travelers have been reported. The situation requires particular attention from certain groups. Pregnant women or those planning to become pregnant should consult their healthcare provider before traveling to any area with a known Zika risk, as local transmission is possible.
Risk is not uniform throughout the country, as mosquito activity is higher in certain regions and seasons. The Aedes aegypti mosquito thrives in urban environments like Bangkok and bites during the day. The presence of the virus necessitates awareness and precautionary measures for all travelers.
Prevention Strategies for Travelers
The most effective way to prevent Zika is to avoid mosquito bites. Because the virus can also be transmitted sexually, travelers should take several precautions.
- Use an Environmental Protection Agency (EPA)-registered insect repellent containing active ingredients such as DEET, picaridin, or oil of lemon eucalyptus. Repellent should be applied to exposed skin after sunscreen.
- Wear appropriate clothing like long-sleeved shirts and long pants to create a physical barrier. Treating clothing and gear with permethrin, an insecticide, offers an additional layer of protection, especially during daytime hours when Aedes mosquitoes are most active.
- Choose accommodations with air conditioning or intact window and door screens to significantly reduce your exposure to mosquitoes indoors. Keeping doors and windows closed helps prevent mosquitoes from entering living spaces.
- Use condoms to reduce the chance of sexual transmission. This is a consideration both during the trip and after returning home, particularly if a partner is pregnant or planning to become pregnant.
Recognizing Zika Virus Symptoms
Many people infected with the Zika virus do not develop any symptoms. When symptoms do appear, they are often mild and begin two to seven days after being bitten by an infected mosquito, usually lasting for several days to a week.
The most frequently reported signs of an acute Zika infection include:
- A low-grade fever
- A maculopapular rash (a flat red area covered with small bumps)
- Joint pain
- Conjunctivitis, more commonly known as red eyes
- Muscle pain and headaches
Because the symptoms are generally not severe and overlap with those of other tropical diseases like dengue, many people may not realize they have been infected. This asymptomatic nature means a person can transmit the virus without feeling sick, underscoring the importance of prevention.
Health Complications Associated with Zika
The primary public health concern with the Zika virus is its effect on fetal development. When a person is infected with Zika during pregnancy, the virus can pass to the fetus, leading to a range of serious birth defects known as congenital Zika syndrome. This risk is present regardless of whether the pregnant individual showed any symptoms.
The most widely recognized of these defects is microcephaly, a condition where a baby’s head is much smaller than expected, which is often associated with underlying brain defects and developmental disabilities. Other issues can include damage to the fetal brain, vision and hearing problems, and limb abnormalities.
Zika infection has also been linked to an increased risk of Guillain-Barré syndrome (GBS). GBS is a rare neurological disorder where the body’s immune system attacks its nerve cells, causing muscle weakness and, in some cases, paralysis. While most people recover, it can be a serious condition requiring intensive medical care.
Guidance for Suspected Zika Infection
Travelers who develop Zika-like symptoms during or after their trip to Thailand should consult a healthcare provider. Be sure to inform the doctor about your recent travel history, including the specific locations visited, to help with diagnosis.
Zika is confirmed through laboratory testing of blood or urine samples that detect the virus’s genetic material or antibodies. An accurate diagnosis is important for pregnant individuals or couples trying to conceive.
To prevent sexual transmission after potential exposure, public health agencies have specific guidelines. The CDC advises that after travel to an area with Zika risk, women should wait at least two months and men should wait at least two months before trying to conceive with a partner.