For the first time in South Korea, a domestic case of Ozu virus—a tick-borne disease previously confined to Japan—has been confirmed in an 80-year-old woman who had not traveled abroad. The virus, transmitted by the bush tick Haemaphysalis longicornis, was detected in a sample taken last November, according to a report by YTN and the Korea Disease Control and Prevention Agency (KDCA). The patient, who had been working in her front garden, recovered after treatment, but the absence of a specific cure or vaccine underscores the importance of prevention.
The Ozu virus, first identified in Ehime Prefecture, Japan, in 2018, has caused only a handful of infections there, including one fatal case in 2023 when a 70-year-old woman died from myocarditis linked to the virus. Symptoms—fever, chills, and muscle pain—mirror those of severe fever with thrombocytopenia syndrome (SFTS), another tick-borne illness common in Korea, making diagnosis challenging. With no targeted treatment available, experts emphasize early diagnosis and supportive care as critical.
Tick-borne diseases are a growing public health concern in Korea, where ticks thrive in grassy areas, farmland, and even urban green spaces. The KDCA warns that prevention is the only reliable defense: wearing long sleeves and pants, applying tick repellent, and regularly checking for ticks after outdoor activities. Pet owners are advised to monitor their animals closely, as ticks can easily latch onto dogs during walks in wooded or overgrown areas.
Domestic Spread and Public Health Response
This is the first confirmed case of Ozu virus infection in Korea without a history of travel to Japan or other endemic regions. The KDCA has not yet issued a formal alert, but the agency is monitoring the situation closely. According to Dr. Hyeok-Kyun Jang, head of the Viral Analysis Division at the KDCA, “There is currently no specific treatment for Ozu virus, but symptomatic and supportive care can be effective if the patient is diagnosed early.” He added that the KDCA is collaborating with Japanese health authorities to better understand the virus’s behavior and potential for spread.
The discovery raises questions about whether Ozu virus has been circulating undetected in Korea for some time. While the KDCA has not confirmed additional cases, the agency is urging healthcare providers to remain vigilant for symptoms consistent with tick-borne illnesses, especially in patients with recent exposure to outdoor environments.
Symptoms and Diagnosis Challenges
The symptoms of Ozu virus infection—fever, chills, headache, and muscle pain—are nearly identical to those of SFTS, another tick-borne disease endemic to Korea. This overlap complicates diagnosis, as both illnesses require similar laboratory tests to distinguish between them. The KDCA recommends that patients presenting with these symptoms and a history of tick exposure be tested for both viruses.
Dr. Jang noted that while SFTS has a higher fatality rate, Ozu virus has also proven deadly, as seen in the 2023 Japanese case. “Given the lack of specific treatments or vaccines, prevention remains our best strategy,” he said. The KDCA has not yet released detailed guidelines for Ozu virus, but its advice for SFTS—avoiding tick-infested areas and using repellents—applies equally.
Prevention: A Critical Public Health Message
With tick populations expanding across Korea, public health officials are stressing the importance of preventive measures. The KDCA recommends the following steps to reduce the risk of tick-borne illnesses:
- Wear long-sleeved shirts and long pants when outdoors, especially in grassy or wooded areas.
- Apply tick repellents containing permethrin or DEET to clothing and skin.
- Conduct daily tick checks on yourself, children, and pets after outdoor activities.
- Keep lawns and gardens well-maintained to minimize tick habitats.
- Use tick collars or topical treatments for pets.
For those who do find a tick attached to their skin, the KDCA advises removing it promptly with fine-tipped tweezers, grasping it as close to the skin as possible, and pulling upward with steady, even pressure. After removal, clean the bite area with rubbing alcohol or soap and water.
Looking Ahead: Next Steps and Research
The KDCA is working with Japanese researchers to better understand the Ozu virus’s transmission dynamics and potential for local spread. While no specific treatment or vaccine exists, the agency is monitoring international research for developments. In the meantime, the focus remains on public education and preventive measures to limit the risk of infection.
For the latest updates on tick-borne diseases in Korea, visit the KDCA’s official website or consult with a healthcare provider if you experience symptoms after potential tick exposure. If you or a loved one is struggling with the emotional impact of a tick-borne illness diagnosis, the Korean National Center for Mental Health offers resources and support.
As Korea continues to grapple with emerging infectious diseases, vigilance and proactive prevention remain the most effective tools in protecting public health.
Have you or someone you know experienced symptoms after tick exposure? Share your story in the comments or on social media to raise awareness. For official updates, follow the Korea Disease Control and Prevention Agency on their website.
