A new bunyavirus has already been isolated as a possible pathogen of the tick bite cases in several Chinese provinces including Henan.

But so far experts cannot yet confirm that virus is the culprit causing the infections, said Wang Shiwen, a researcher with the virology institute of the Chinese Center for Disease Control and Prevention.

Despite that the pathogen remains unclear, "there is no need to panic as the disease can be cured with timely detection and treatment," he said at a workshop on the epidemic in Shangcheng County, Henan on Sunday.

Bunyaviruses are largely transmitted in nature by vertebrates and arthropods like mosquitoes, ticks, and sandflies, experts said.

Symptoms of infections in humans include hemorrhagic fever and meningitis.

Transmitted in a similar way as pathogens carried by mosquitoes, the illness is also preventable, he added.

Chinese health authorities have been trying hard to lessen public fear about the tick-borne disease, which as of Sept 10 has reportedly spread to 12 provinces including Henan and Shandong, and claimed at least 31 lives.

Experts sent by the Ministry of Health to the site in Henan outlined preventative measures on Sunday, including that medical staff in infected areas should receive training on the prevention and treatment of the disease recognized as human granulocytic anaplasmosis (HGA).

The affected areas, however, have yet to be recognized, Wang said.

A preliminary study showed that women and the elderly are most at risk of contracting the disease.

"They usually work the farmland and are thus more likely to be exposed to tick bites," Wang said.

The Ministry of Health has designated experts to develop new clinical guidelines for the diagnosis and treatment of the tick-borne disease.

The last set of guidelines was issued in 2008.

Trainings on diagnosis and treatment have been organized by experts including Wang, who arrived in Shangcheng County on Friday to teach local medics.

After the first such case was detected in 2007, the Henan provincial health authority announced 557 reported cases, including 18 deaths, on Wednesday.

After the media inquired whether officials failed to publicize the epidemic in a timely manner, authorities from the Henan provincial center for disease control and prevention (CDC) said the procedure to confirm that a fatality was caused by a certain infection is complicated and takes time.

Xu Bianli, deputy director of the Henan CDC, said the statistical departments have a difficult time collecting data as some victims suffering from the disease died at home, largely off the government's radar.

Investigations have already been launched regarding neglected cases disclosed by media reports, he noted.

(China Daily September 14, 2010)