Polio is disturbingly on the rise in Pakistan and health officials said Wednesday the number of fresh polio infections in 2013 had already passed the total for the whole of 2012.
Pakistan is one of only three countries in the world where the highly infectious disease which cripples limbs remains endemic.
Opposition from militant groups has hampered efforts to vaccinate children against polio in Pakistan and officials said violence was part of the reason for the increase in cases.
Six cases were in eastern Punjab province, four in Sindh in the south and nine in northwestern Khyber Pakhtunkhwa, but by far the bulk of the infections -- 43 -- were in the tribal areas along the Afghan border.
The Pakistani Taliban banned polio vaccinations in the tribal region of Waziristan last year, alleging the campaign was a cover for espionage.
"The main reason for the outbreak is militancy in the northwest. Vaccination teams are unable to reach the tribal areas because of risks to their lives," the official said.
Polio cases reached a low of 28 in 2005 but have risen since, reaching a peak of 198 in 2011.
In August health officials warned of a serious polio outbreak in the northwest, saying more than 240,000 children had missed vaccination because of the Taliban ban.
Elsewhere in the country, health workers giving out polio drops have been attacked and killed, including in the largest city Karachi.
On Monday the World Health Organization linked an outbreak of polio in Syria that has paralysed 13 children to a strain of the virus from Pakistan.