Photo courtesy of CDC

Taipei, Sept. 4 (CNA) Two women in New Taipei City's Zhonghe District, both in their 60s, have been confirmed as this year's first indigenous chikungunya fever cluster, the Centers for Disease Control (CDC) said Wednesday.

The latest case involved a woman who has not traveled abroad recently and sought medical attention after experiencing a high fever, muscle and joint pain on Aug. 23, according to CDC Deputy Director-General Philip Lo (羅一鈞).

The woman then developed a rash and sought medical attention for a second time on Aug. 29. Later that day, she was confirmed as having contracted Chikungunya fever after her sample tested positive for the virus, Lo said.

The woman's symptoms have improved and no one she came into contact with has shown signs of symptoms, Lo added.

This is the second indigenous chikungunya fever case reported in Zhonghe this year. The first case was diagnosed Aug. 26.

The two Zhonghe patients live in neighboring boroughs and both have taken part in activities along same hiking trails near their homes, Lo said, adding that local health department determined they likely contracted the virus in the mountain area and identified it as this year's first indigenous cluster case of chikungunya fever.

The genome sequence of the chikungunya virus strain found in the two indigenous cases in Zhonghe was identical to cases from Myanmar and the virus could have come from imported cases from Myanmar that caused cluster infections along the mountain trails, Lo said.

According to a fact-finding visit, health officials found a number of vegetable gardens and mountain structures in the area that are ideal breeding conditions for mosquitoes, Lo noted.

A disinfection campaign has been conducted in the neighborhood where the two women live as well as Zhonghe's Huaxin Street, the main settlement for new immigrants from Myanmar, including spraying chemical insecticide and cleaning possible breeding sites for mosquitoes.

In addition, eight hiking trails in the neighborhood have also been blocked off since Aug. 30 to prevent infection. People who enter the controlled areas could face a fine of NT$60,000-NT$300,000 (US$1,916-US$9,581), according to Lo.

Aside from the three indigenous chikungunya cases, there have been 54 confirmed imported cases in Taiwan so far this year, most of which originated in Southeast Asia, the highest level for the same period of the year since the mosquito-borne disease was designated a notifiable disease in 2007.

Thirty-six of the imported case came from Myanmar, eight from Thailand, five from the Maldives, two from Indonesia and one each from the Philippines, Malaysia and India, according to CDC statistics.

The CDC has issued a level 1 travel warning for chikungunya for people traveling to Thailand, India, the Maldives and Myanmar.

Like dengue fever, chikungunya fever is also spread by the Aedes mosquito and has an incubation period of two to 12 days.

The Aedes aegypti is more likely to spread dengue fever, while the Aedes albopictus usually carries the chikungunya virus. However, both types of mosquito can spread both diseases.

Also like dengue fever, the symptoms of chikungunya include the abrupt onset of fever, headaches, joint and muscle pains, nausea, and fatigue.

Although dengue fever has been more common and dangerous than chikungunya in the last few years, the joint pain associated with the latter can last for years.

(By Chang Ming-hsuan, Sunrise Huang and Evelyn Kao)
Enditem/AW