Polio strain spreads to China from Pakistan - Bại liệt lan từ Pakistan tới Trung Quốc
Polio has been found in China for the first time since 1999 after spreading from Pakistan, the World Health Organization (WHO) has confirmed.
It said a strain of polio (WPV1) found in China was genetically linked with the type now circulating in Pakistan.
At least seven cases have now been confirmed in China's western Xinjiang province, which borders Pakistan.
The WHO warned there was a high risk of the crippling virus spreading further during Muslim pilgrimages to Mecca.
Polio (also called poliomyelitis) is highly infectious and affects the nervous system, sometimes resulting in paralysis.
It is transmitted through contaminated food, drinking water and faeces.
'Right things done'
On Tuesday, the WHO said the polio cases in Xinjiang had been detected in the past two months.
The Chinese authorities are now investigating the cases, and a mass vaccination campaign has been launched in the region.
"So far all the right things are being done," WHO spokesman Oliver Rosenbauer told Reuters news agency.
Polio was last brought into China from India in 1999. China's last indigenous case was in 1994.
Pakistan is one of a handful of countries where polio remains endemic.
WHO officials had been warning for some time that the virus was spreading within the country to previously uninfected areas.
The UN's children fund, Unicef, has said that eradicating polio from Pakistan depends on delivering oral vaccines to each and every child, including the most vulnerable and the hardest to reach.
Polio was virtually eliminated from the Western hemisphere in the 20th Century.
UN issues warning on Pakistan polio rates
Pakistan has continued to see a rising numbers of polio cases since the beginning of 2011, the UN children's fund, Unicef, has said.
The agency says that 63 cases have been diagnosed so far, compared to 36 cases over the same period last year.
The bulk of the cases are in the province of Balochistan, which has reported 22 cases this year.
The UN says that Pakistan could be the "last polio reservoir worldwide" standing in the way of eradication.
"We must ensure access to all children as specified in the president's National Emergency Action Plan for Polio Eradication in Pakistan," Unicef South Asia Regional Director Daniel Toole said.
"We have a huge task ahead of us, and we must build on lessons learned and act now."
Mr Toole - who is in Pakistan to meet senior government and UN officials - has reiterated Unicef's "commitment to the eradication of polio" and emphasised the need urgently to improve the battle against the spread of the disease.
The UN says the virus circulated in five high-risk districts in Balochistan and has now spread to areas not previously infected for the past five years, including the country's tribal areas and the provinces of Sindh and Khyber Pakhtunkhwa.
Unicef says eradicating polio from Pakistan depends on delivering oral polio vaccines to each and every child, including the most vulnerable and the hardest to reach.
"This massive undertaking can succeed, but only with the tireless efforts and commitment of the people of Pakistan," a Unicef statement said.
The next polio vaccination campaign will be held 19-21 September, targeting 16.5 million children in the districts at the highest risk.