The Balochistan health department confirmed the fourth polio case of the year in the province on Wednesday.
The number of children affected by polio in Pakistan this year has reached 20.
A seven-year-old child was diagnosed with the virus in District Sohbatpur.
This year, 10 cases have been reported from Khyber Pakhtunkhwa, six from Sindh and four from Balochistan.
At least 128 polio cases were recorded across the country in 2019.
All the new cases are from families on the lower end of the socioeconomic scale. Officials have also confirmed that the polio virus was detected in 50% of the sewerage samples collected from across Pakistan.