Tourists should be careful when enjoying the beaches of Kenting as a major jellyfish invasion has been reported in waters off the popular tourist area along Taiwan's southern coast, the Kenting National Park administration said earlier this week. A jellyfish invasion often occurs from May to July, when seasonal southwesterly winds tend to bring jellyfish to waters in the Kenting area, said Tsai Feng-fu, a park administration official. The jellyfish invasion is currently most severe in waters off the Nanwan area, while other coastal areas such as Baisha, Dawan and Hsiaowan have also been affected, Tsai said. Beaches in those areas are among the top attractions in Kenting. The most commonly seen jellyfish in Kenting has been the physalia physalis, more commonly known as the Portuguese man o' war. The toxic jellyfish, whose tentacles can appear blue to purple, is hard to detect because its color is similar to that of the sea. When people get stung by the jellyfish, they will usually not feel it until emerging from the water, and will normally suffer rashes and inflammation, Tsai said. There are medical stations at Nanwan and Hsiaowan where people stung by the jellyfish can receive treatment. In Baisha and Dawan, coastal patrol personnel will provide assistance in the event of an emergency, Tsai said. Several cases of swimmers stung by jellyfish have been reported over the past week. Some of them received first-aid at the medical stations and others had to seek further medical treatment at area hospitals. Tsai said most jellyfish stings can be treated by cleaning the affected area with water and then an ammonia solution. In serious cases, jellyfish stings may lead to nausea, vomiting, diarrhea, difficulty breathing and even unconsciousness, the Hengchun Tourism Hospital in Pingtung County said.