TAIPEI (Taiwan News) — Taiwan confirmed on Wednesday its first imported case of Plasmodium knowlesi malaria in two decades, prompting the Centers for Disease Control to raise its travel advisory for the Philippines to level 1.
The case is a foreign national in his 30s who traveled to Palawan in early June. He did not take anti-malarial prophylaxis and engaged in ecotourism activities, during which he was bitten by mosquitoes, according to CNA.
The man began experiencing symptoms, including headache, fever, muscle aches, dark-colored urine, and drowsiness, before returning to Taiwan on June 19. His condition worsened, and he was hospitalized on June 27 with shortness of breath, dizziness, and decreased urine output.
The patient was subsequently diagnosed with malaria and remains under hospital care. Health authorities are closely monitoring his condition and conducting follow-up tests.
This is Taiwan’s second confirmed imported P. knowlesi case on record and the first since 2005. The earlier case involved a Taiwanese man in his 60s who also visited Palawan and was bitten by mosquitoes during ecotourism activities.
P. knowlesi is a zoonotic malaria parasite primarily infecting long-tailed and pig-tailed macaques in Southeast Asia. It is transmitted to humans by mosquitoes and has increasingly been reported in human cases across the region since 2004.
CDC Deputy Director-General Lo Yi-chun (羅一鈞) said early P. knowlesi symptoms often resemble influenza, with fever being the most common. Other symptoms include headache, joint and muscle pain, nausea, vomiting, and fatigue, typically within seven to 30 days after infection.
Without timely treatment, the disease may progress to cyclical chills, high fever, and sweating, potentially leading to serious complications such as liver and kidney failure, pulmonary edema, shock, jaundice, encephalopathy, and coma.
In response to the latest case, the CDC raised its travel health notice for the Philippines to level 1, urging travelers to the country to take preventive measures against mosquitoes. Recommendations include wearing long-sleeved clothing and using insect repellent.
Those at higher risk of severe malaria, or individuals planning extended stays in forested areas, are advised to consult a travel medicine clinic at least one month before departure and consider prophylactic anti-malarial medications based on medical guidance.
As of July 1, Taiwan has reported 12 imported malaria cases so far this year, marking the highest number for this period in nearly 19 years. Cases have been linked to travel in Kenya, Sierra Leone, the Solomon Islands, Tanzania, Madagascar, Benin, the Philippines, and the Central African Republic. Affected patients ranged in age from their 20s to their 60s.
Lo added that malaria-transmitting mosquitoes are extremely rare in Taiwan, limited to low-density populations in a few southern mountain stream areas. Taiwan has not recorded any indigenous malaria cases for decades, due to the absence of suitable mosquito vectors and animal reservoirs.
