CDC updates testing directives for H7N9 avian flu

UPDATED::Based on international research, the incubation time of the H7N9 avian influenza has been increased to 10 days from the previous seven days, a physician said

By Alison Hsiao  /  Staff reporter

Sat, Apr 27, 2013 - Page 1

The Centers for Disease Control (CDC) yesterday updated H7N9 avian influenza virus testing directives for hospitals following the first confirmed H7N9 infection in Taiwan, whose throat swab samples tested negative twice for the virus before the infection was finally confirmed via sputum specimen testing.

The Central Epidemic Command Center confirmed the first imported case of H7N9 infection in Taiwan on Wednesday, and doubts had been raised over its delayed announcement of the confirmation and the ineffective testing.

CDC Director-General Chang Feng-yee (張峰義) said the center had to undertake genome sequencing of the virus before making the confirmed case public and it is incorrect to say that throat swab testing is “ineffective.”

“The H7N9 virus was detected in the sputum sample using a real-time polymerase chain reaction [PCR] test kit. However, to be absolutely sure of the result, it is necessary to use genome sequencing, which later confirmed the infection and found that the virus strain was highly similar to the one found in Shanghai, confirming that the virus was imported,” Chang said.

“Because the throat swab samples tested negative twice after the patient was hospitalized does not mean that the testing was ineffective. There were no such pathogens in his throat. The patient developed a fever, but exhibited no respiratory or gastrointestinal symptoms when he first sought medical attention. It indicates that the virus is most active in the lower respiratory tract and the lungs,” Chang said.

CDC physician Philip Yi-chun Lo (羅一鈞) said the center now advises hospitals to obtain sputum samples from suspected cases that have coughed up phlegm, recently had pneumonia or exhibited other symptoms.

Lo said that based on the latest international research on H7N9 avian influenza, the virus’ estimated incubation period has been increased to 10 days from seven days.

“This change will affect the time needed to conduct self-health management for those who have come into close contact with an infected patient. They now have to be followed closely by health authorities until Tuesday, three days longer than the previously stated,” Lo said, adding that the three contacts who exhibited upper respiratory symptoms are recovering and all the other contacts have not exhibited any symptoms.

Meanwhile, Bureau of Animal and Plant Health Inspection and Quarantine Deputy Director Huang Kuo-ching (黃國青) said the effective date of the ban on live poultry slaughter in markets has been shifted to an earlier date of May 17, one month earlier than previously stated, as a preventive measure following the first imported H7N9 infection.

Speaking on the government’s control measures on the expected 14,000 Chinese tourists traveling to Taiwan during China’s May Day holiday, Tourism Bureau official Lin Mei-yan (林美燕) said the bureau has asked travel agencies to be on high alert on the health of tourists, and has set up a round-the-clock hotline.

“No travel restrictions will be imposed on Chinese tourists. The threshold for that kind of restriction is pretty high,” Chang said.

Officials from the Ministry of Economic Affairs (MOEA), the Ministry of Finance, the Consumer Protection Committee and the Fair Trade Commission were also present at the press conference, where it was announced that the government has been monitoring the sales of face masks and there is little concern of stock shortages.

“Local manufacturers are able to produce 800,000 masks a day, and the four major supermarket chains have only sold approximately 23,000 masks per day this month. Consumers are advised to buy masks according to their immediate needs since there is no need to stock up,” MOEA official Chen Mi-shuan (陳秘順) said.