Existing and re-emerging infectious diseases are a greater threat than biological weapons, experts said at an international meeting in Beijing yesterday, the same day Macao issued warnings of an expected dengue fever outbreak.

"Although we must keep alert and make preparations against the intentional use of bioweapons and bioterrorism, naturally occurring outbreaks are still the biggest enemy," Cao Wuchun from the Academy of Military Medical Sciences told China Daily.

Cao, deputy director of the academy's Institute of Microbiology and Epidemiology, was speaking on the opening day of the International Workshop on Infectious Diseases and Bio-safety, and said that China is developing technology to resist possible attacks.

Innovations such as devices that warn of biological agents are vital for national defense and also for large public events like the Beijing 2008 Olympic Games, Cao added.

Wang Yu, director of the Chinese Center for Disease Control and Prevention, said that there are new challenges from infectious diseases such as influenza, HIV/AIDS, SARS (severe acute respiratory syndrome), viral hepatitis and even hemorrhagic fevers like Marburg disease and Ebola.

The State Administration of Quality Supervision, Inspection and Quarantine issued an order on Monday for checks for Marburg disease to be strengthened. Last week, the Ministry of Health denied rumors that there had been a case of Ebola in Shenzhen.

Wang told the workshop that since 1973 about 40 new pathogens, half of which are caused by viruses, have been discovered.

SARS killed almost 800 people, mostly in Hong Kong and the Chinese mainland, in a worldwide outbreak that infected more than 8,000 by the end of 2003.

There are 820,000 Chinese people with the parasitic blood condition schistosomiasis (snail fever or bilharzia) and a further 40 million people are at risk of contracting it, while 1.3 million new tuberculosis cases are reported each year, said Wang.

Cao said threats can also come from accidental leakage of pathogens from laboratories, as took place in an outbreak of SARS in Beijing last year that spread to Anhui Province.

Since 2003, the government has strengthened procedures at various levels, said Cao, to safeguard public health and protect against biological threats.

Also on Tuesday, Macao's Health Bureau warned citizens to be on high alert for dengue fever, which is very likely to break out this summer, as it usually does every three to four years.

The bureau said that it would mobilize a large number of volunteers to aid prevention measures from April 6 to June 25.

(China Daily, Xinhua News Agency April 6, 2005)