Story highlights Outbreak reported in western Xinjiang province, which borders Pakistan

Polio a contagious viral illness that can cause paralysis, death

Among the ten cases confirmed, six are in children under three years

WHO: Virus genetically linked to polio cases circulating in Pakistan

An outbreak of polio has been confirmed in China for the first time since 1999, leaving one person dead and hospitalizing another nine, according to the World Health Organization (WHO).

The disease, a contagious viral illness that in its most severe form causes paralysis, difficulty breathing and sometimes death, broke out in the prefectures of Hotan and Bazhou in the country's western Xinjiang province.

Among the ten cases confirmed, six are in children under three years old and four are young adults.

The WHO said evidence indicates the virus is genetically linked to polio cases currently circulating in Pakistan, which borders Xinjiang. Pakistan has been affected by the nationwide transmission of the same WPV1 strain.

It also warned the virus could spread beyond the current affected area.

"Although other areas in China or other countries are not immediately at risk due to the geographic distance to the affected province, the polio virus can travel great distances and find susceptible populations, no matter where they live," Helen Yu, from the WHO's Beijing office told CNN.

According to China's Center for Disease Control and Prevention, the Ministry of Health has dispatched a group of public health experts to the affected region to help treat the virus.

It said the local government had launched a mass vaccination campaign starting in early September. WHO confirmed initial vaccination campaigns carried out by mid-September had reached over 3.5 million children -- children being particularly vulnerable to polio.

Further vaccination campaigns will be conducted in the near future to ensure this outbreak is brought completely under control, according to the health ministry.

"No matter how long a country has been polio-free, as long as global polio eradication has not yet been achieved, the risk for importation remains and constant vigilance is required." said Yu.

Polio, also known as poliomyelitis, is usually transmitted through contaminated food and water. It invades the nervous system and often leads to permanent paralysis. It can be prevented by immunization.

This is the first outbreak of polio in China since 1999, when a case was reportedly brought into the country from India.