Poor sanitation and a naturally wet climate create a fertile breeding ground for pests such as mosquitoes and rodents, which sometimes carry infectious diseases. With a number of different large scale efforts, the Taiwan CDC also encourages citizens to take proper measures to prevent the spread of infectious diseases. This primarily comes in the form of taking out trash, emptying water containers and keeping one’s home clean. In most cases, these diseases are only spread via infected pests and not from person to person. Taking away the types of environments that the pests can thrive in means a lower disease rate. Here is more information about the diseases impacting Taiwan and the efforts to combat them.

Hantavirus

Hantavirus is one of many infectious diseases impacting Taiwan that stems from rodents. There were a total of 44 infections between 2017 and 2026 – most of which were found on the northern part of the island in or near New Taipei City. One can become infected by simply breathing in or coming into contact with infected rat feces, urine or saliva. Symptoms include elevated body temperature, muscular pain, nausea and diarrhea. However, the mortality rate for this strain in Asia is much lower than in other parts of the world with only one confirmed death over that span. Although still rare, a deadlier and more common strain of the disease is also found in the southwest part of the United States.

Two Taiwanese men in their 70s were infected with the virus in 2026. A man who died in January was immunocompromised and had other preexisting conditions. A couple of the rats found near his house tested positive for the virus.

Environmental protection agencies respond to incidents such as these by setting traps and exterminating areas with confirmed cases of the virus to help limit its spread. Yearly numbers have always been low, but between 2022 and 2025, there were no more than four total cases each year.

By not leaving out food and keeping one’s area free of clutter, homeowners automatically put themselves in a better position to protect themselves from infestation. The use of gloves and a mask to clean up rat droppings has helped to curb the infection rate as well.

Chikungunya Fever

Infected mosquitoes that originate from China and south East Asian countries have found their way into Taiwan due to increased rainfall and typhoons. Although chikungunya fever has a low mortality rate, people who contract the disease experience joint pain throughout the body, fatigue, nausea and headache. It takes an average of four to eight days for symptoms to appear and about a week to recover.

There are an average of well under 100 infections each year in Taiwan, but in 2019, there were 107. These mosquitoes thrive in pockets of stagnant water like rain barrels, potted plant holders and gutters. In response to the uptick in infections, the government imposed a fine of up to $7,500 TWD for any person who leaves open water containers out in public. Although there have been fewer cases in following years, 2025 saw the highest number of cases since 2019 at 46. By implementing these measures, it has made eliminating the spread of diseases impacting Taiwan that involve mosquitoes much easier.

The government places ovitraps in a variety of infested areas to help determine the number of mosquitoes that carry the disease. An ovitrap is a shallow bucket of water in a shaded area, which is specifically used to count the number of mosquito eggs that appear over time. After data is collected, the areas that need attention are sprayed with insecticide. After the spike in infections for 2019, 2020 saw a grand total of three.

Dengue Fever

Dengue fever is another example of a disease that mosquitoes, both native and foreign to the island, are known to spread. Unlike the other two, dengue fever is primarily found on the south end of Taiwan which shows that the risk for diseases from pests extends to all parts of the island. Dengue fever is much more common. Primary symptoms include fever, headache, muscle pain and pain behind the eyes. Around 1% of cases can develop into severe dengue in which the person has difficulty breathing due to plasma leakage. Older adults with weaker immune systems are at a much greater risk to have this happen.

The number of cases varies significantly from year to year depending on several factors like weather patterns and how much the population has achieved herd immunity. Migrant workers from other countries like the Philippines and Vietnam bring the infection from their home country into Taiwan, increasing the overall rate of the disease impacting Taiwan. It is estimated that the vast majority of baseline cases of mosquito-related diseases originate in other south east Asian countries.

The government has also stepped in to teach people about the seriousness of the disease and how to stay healthy. There is a widespread awareness campaign about how to prevent infections around one’s home as well as protection methods one can use outside the home like covering up skin with light colored clothing.

Just like Chikungunya Fever, there are large-scale efforts to set ovitraps and collect data for the purposes of determining which areas to spray. In 2023, there were 26,706 total cases, but in 2025 there were less than 300. About 44 people died of the disease in 2023, and each year less than 1% of people die from Dengue Fever. The CDC also made surveillance of the disease widely available with more than 430 hospitals signed up to report data about the disease.

Conclusion

There are many other infectious diseases in Taiwan that are transmitted by rodents or mosquitoes besides the three discussed in this article. While herd immunity is attainable through vaccination and widespread recovery from infection, there will always be new variants and other external factors, such as climate, that cause brand new spikes in infection. However, by continuing with the collective effort to curb the spread on the part of both the Taiwan CDC and the Taiwanese citizens, the country will be a much healthier place for both citizens and visitors alike.

– Logan Hessek

Logan is based in Northglenn, CO, USA and focuses on Good News and Global Health for The Borgen Project.

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