Taiwan’s Centers for Disease Control (CDC) confirmed the country’s first imported case of Plasmodium knowlesi malaria in two decades, marking a rare public health development that reignites attention to zoonotic diseases linked to eco-tourism in Southeast Asia.
The patient, a foreign national in his 30s, had recently returned from Palawan Island in the Philippines — a well-known eco-tourism hotspot — where he reportedly engaged in outdoor activities without taking any malaria prophylaxis. After returning to Taiwan on June 19, he began experiencing symptoms including fever, dark-colored urine, headache, muscle pain, and general fatigue. His condition worsened, leading to a hospital visit on June 27, where he was diagnosed with P. knowlesi malaria and subsequently hospitalized.
🔬 Why This Case Matters: A Zoonotic Red Flag
This is only the second recorded case of Plasmodium knowlesi malaria in Taiwan’s history. The first occurred in 2005 and also involved a traveler returning from Palawan. Unlike other common human malaria parasites, P. knowlesi is a zoonotic parasite, meaning it primarily infects wild macaques (long-tailed and pig-tailed) in Southeast Asia and is transmitted to humans by Anopheles mosquitoes.
Though long known to infect animals, P. knowlesi gained international attention only after 2004, when human infections began rising across countries such as Malaysia, Indonesia, Thailand, Singapore, Vietnam, and the Philippines. Its ability to multiply every 24 hours makes it particularly dangerous, often leading to rapid-onset symptoms and complications if untreated.
🦟 Taiwan’s Current Risk and Response
According to CDC spokesperson Lo Yi-chun, the chance of a domestic outbreak remains extremely low because:
- Taiwan lacks the macaque hosts required for the zoonotic transmission cycle.
- The local Anopheles minimus mosquito (Taiwan’s only known vector) exists at low densities, mainly near mountain streams in the south.
- There is no recent history of local transmission of P. knowlesi.
Despite this, the CDC is treating the event seriously and has upgraded its travel alert to Level 1 (Watch) for the Philippines, urging travelers to take preventive measures when visiting known malaria-risk regions.
✈️ Rise in Travel-Linked Infections
As of July 1, 2025, Taiwan has recorded 12 imported malaria cases — the highest for this time of year since 2007. These include both P. falciparum and P. vivax, which are more commonly associated with imported malaria cases, especially from Africa and Southeast Asia.
The resurgence of international travel following pandemic-era restrictions may be contributing to this increase. Public health authorities now emphasize the importance of pre-travel health counseling, including vaccinations, malaria prophylaxis, and personal protection measures (such as using DEET-containing repellents and mosquito nets).
🧬 About Plasmodium knowlesi
- Type: Zoonotic malaria parasite
- Primary hosts: Long-tailed and pig-tailed macaques
- Vector: Forest-dwelling Anopheles leucosphyrus group mosquitoes
- Symptoms: Fever, chills, headache, dark urine, muscle pain, drowsiness
- Risks: Rapid replication can lead to severe complications, including kidney failure or death, if untreated
- Diagnosis: Microscopy, rapid diagnostic tests (RDTs), and PCR
- Treatment: Typically includes artemisinin-based combination therapy (ACT)
📌 FAQs
What is Plasmodium knowlesi malaria?
It is a form of malaria caused by a parasite that typically infects macaques and is transmitted to humans through mosquito bites in forested Southeast Asian regions.
Is P. knowlesi common in Taiwan?
No. Taiwan has had only two imported cases in 20 years. The local ecosystem lacks the macaque hosts and the appropriate mosquito species necessary for sustained transmission.
How can travelers protect themselves against malaria?
By taking antimalarial prophylactic drugs, using insect repellent, wearing long-sleeved clothing, and sleeping under mosquito nets.
What symptoms should I watch for after travel to Southeast Asia?
Early symptoms include fever, chills, headaches, dark urine, and body aches. Seek medical attention immediately if these occur after return.
Will this case lead to border control measures or quarantines?
No. Malaria is not transmitted person-to-person. However, Taiwan’s CDC has issued travel alerts and continues to monitor returning travelers from malaria-endemic countries.
