The Taiwan Centers for Disease Control (Taiwan CDC) stated that outbreaks of dengue fever and other mosquito-borne infectious diseases are continuing internationally, with dengue activity recently increasing in neighboring Southeast Asian countries and raising the risk of infection while traveling abroad. According to weather forecasts, El Niño conditions may strengthen further in the coming months. With the summer vacation travel season currently at its peak, the  Taiwan CDC urges the public to take appropriate mosquito bite prevention measures while traveling abroad. Those who develop symptoms within 14 days after returning to Taiwan should promptly seek medical attention and proactively inform their physician of their travel history to facilitate diagnosis.

The Taiwan CDC explained that eight new imported dengue cases were reported in Taiwan last week (July 28–August 3), including three cases associated with a cluster of infections acquired in Cambodia. The three individuals, two males and one female ranging in age from their teens to their 30s, traveled together to Cambodia in mid-July this year to participate in an exchange program. After returning to Taiwan in late July, they developed symptoms, including fever, headache, nausea, muscle pain, and pain behind the eyes, and were diagnosed with dengue after seeking medical attention. Relevant health authorities have conducted breeding-site elimination, chemical control, and other preventive measures around the patients’ residences and places they visited, and are continuing to monitor the health of other members of the group.

According to Taiwan CDC surveillance data, as of August 3 this year, Taiwan had recorded a total of 111 confirmed dengue cases, including seven locally acquired cases, all involving residents of Kaohsiung City. Another 104 cases were imported from Southeast and South Asian countries, with Indonesia accounting for the largest number with 24 cases, followed by Vietnam with 23 and the Maldives with 15. The cumulative number of cases this year is lower than the 130 cases reported during the same period in 2025.

The global dengue outbreak remains ongoing. As of June this year, more than 1.58 million cases had been reported worldwide, primarily in the Americas, with Brazil, Colombia, and Bolivia among the countries reporting higher numbers of cases. In neighboring Asian countries, including Sri Lanka, Vietnam, Malaysia, Cambodia, Laos, and Bangladesh, dengue activity has recently increased and is generally higher than during the same period last year. Sri Lanka has reported more than 84,000 cases so far this year, while cases in Cambodia have also risen rapidly, with more than 28,000 reported to date.

The Taiwan CDC reminds the public that when engaging in outdoor activities in Taiwan or abroad, it is advisable to wear light-colored, long-sleeved clothing and use government-approved mosquito repellents containing effective ingredients such as DEET, Picaridin, or IR-3535 to reduce the risk of mosquito bites.

As dengue outbreaks continue in Southeast and South Asia, the Ministry of Transportation and Communications has asked travel operators to issue reminders to travelers regarding mosquito bite prevention while abroad and health monitoring after returning to Taiwan. Travelers experiencing suspected dengue symptoms, such as fever, headache, pain behind the eyes, or muscle and joint pain, upon arrival in Taiwan should proactively inform airport quarantine personnel. Healthcare institutions should also remain vigilant and thoroughly inquire about patients’ TOCC (travel history, occupation, contact history, and cluster history), use dengue NS1 rapid diagnostic tests when appropriate to assist diagnosis, and promptly report suspected cases.

Taiwan has also recently experienced hot weather with occasional afternoon rainfall across various regions, creating favorable conditions for mosquito breeding. The Taiwan CDC urges the public to follow the four steps – “Inspect, Empty, Clean, and Scrub” – by regularly inspecting their homes and surrounding areas and removing containers that may collect standing water, such as plant saucers, discarded tires, and plastic bags. For large discarded containers, the public may contact local sanitation teams for assistance with disposal. Containers and water storage equipment that need to be retained should be regularly scrubbed to remove mosquito eggs from their inner surfaces and inspected again after rainfall.

Schools at all levels should also continue to monitor campus environments during the summer vacation and immediately remove any containers holding standing water. Particular attention should be paid to toilets, water tanks, and other facilities that have not been used for extended periods, as these can easily become breeding sites for mosquito larvae. Regular inspections should be conducted to reduce the risk of vector mosquito breeding.

For more information on dengue fever, please visit the Taiwan CDC website or call the toll-free Communicable Disease Reporting and Consultation Hotline on 1922 (0800-001922).