Health Officials Warn of Pool Fever Outbreak in Japan

In a startling revelation, Japan is grappling with a significant upsurge in reported cases of “swimming pool fever,” also known as pharyngoconjunctival fever. The National Institute of Infectious Diseases (NIID) made this announcement on November 21, indicating a concerning spike in this particular ailment that is typically associated with inadequately disinfected swimming pools and is commonly spread during the summer months.

The week spanning from November 6 to November 12 has witnessed an unprecedented surge in reported cases of pharyngoconjunctival fever across the nation. Approximately 3,000 pediatric clinics, diligently monitoring and reporting cases, revealed that the average number of patients afflicted with the disease per institution during this period amounted to 3.23 per clinic. This alarming statistic represents the highest recorded figure since 1999, coinciding with the enactment of current infectious disease laws in Japan.

For the first time in the nation’s history, the national average has breached the 3.0 patients mark, a critical threshold prompting local governments to issue alerts. As of now, 25 out of Japan’s 47 prefectures have already surpassed this alert threshold, underscoring the widespread nature of the outbreak.

What is Swimming Pool Fever?

Swimming pool fever is a type of RWI (recreational water illness) attributed to an adenovirus infection and manifests through symptoms such as fever, sore throat, and conjunctivitis. When individuals come into contact with water containing adenoviruses, the virus can enter the body through the eyes, nose, or mouth. In the case of swimming pool fever, the conjunctiva of the eyes and the mucous membranes of the throat are commonly affected. In severe cases, it may even lead to pneumonia. Alarmingly, a significant portion of the affected demographic comprises children under the age of 5.

Adenoviruses are a group of viruses that can infect various parts of the body, including the respiratory tract, eyes, intestines, and urinary tract. There are different types of adenoviruses, and certain strains are responsible for causing pharyngoconjunctival fever.

In the context of swimming pool fever, the transmission of adenoviruses occurs through exposure to contaminated water, especially in inadequately disinfected swimming pools. Adenoviruses are resilient and can survive for extended periods in water, making them particularly problematic in environments where water quality and hygiene measures are not rigorously maintained.

The unprecedented outbreak of swimming pool fever in Japan has not only surpassed historical records but also triggered widespread concern among health authorities. In response to this concerning trend, the NIID is advocating precautionary measures, urging children in nursery schools and their teachers to abstain from attending these facilities if they exhibit any signs of illness. Additionally, the institute is emphasizing the importance of infection-prevention practices, including regular handwashing with soap, avoiding the sharing of towels, and diligently disinfecting frequently touched surfaces and toys.