Beijing is trying its best to contain potential public health risks caused by pests at the Beijing Olympic Games, a leading health official has said.

Reducing the numbers of rats, flies, mosquitoes and cockroaches is at the top of the agenda, said Zeng Xiaotong, secretary-general of the vector biology and control committee under the Ministry of Health (MOH), on Tuesday.

There are various kinds of pest-borne infectious diseases, such as bubonic plague, dengue fever and West Nile virus, which can be transmitted by these pests to humans.

"We are confident of preventing and controlling such outbreaks during the Games," Zeng said.

Since 2005 the Beijing Loving-Motherland Sanitation Movement Committee has called on sanitation workers and Beijing residents to kill pests and improve hygiene.

"The efforts have broadly paid off," Zeng said.

There were complaints about mosquitoes biting all night long from athletes at the Athens Olympic Games, according to Dai Jianping, deputy director of BOCOG's service department.

The major mosquito species in Beijing, culex pipiens mosquito, is the same kind that caused a West Nile Virus outbreak in the US, infecting 15,000 people and killing at least 500 since 1999, Zeng said.

"For that, we've invited experienced US medical experts to Beijing to help with prevention work," he said.

So far there have been no cases of the deadly infection reported in China. According to the MOH, no mosquito-born infectious diseases have been recorded.

The three other major pests were also under control, according to test results, Zeng said.

A citywide surveillance network has been set up to collect information about pests, including the species, population density, activity patterns, and pathogens, so as to help figure out countermeasures for prevention and control.

The 31 Olympic competition venues, the Olympic Village, and the surrounding areas are the primary targets, he said.