As of 30th April 2015, 22 type-1 wild poliovirus (WPV) cases have been reported in year 2015 from 12 districts/ towns/ tribal agencies/ FR areas (compared to 68 in 2014 from 09 districts/ towns/ tribal agencies/ FR areas). Moreover, WPV-1 has also been isolated from 28 environmental samples in 2015 (out of 103 samples for which results are available) from Karachi (Gadap, Baldia and Gulshan-e-Iqbal towns), Hyderabad, Sukkur and Jacobabad in Sindh; Peshawar and DI Khan in Khyber Pakhtunkhwa; Lahore and Rawalpindi in Punjab, Quetta and Killa Abdullah in Balochistan and Islamabad. Two sabin-2 like poliovirus cases have been reported so far in 2015 from Khyber agency in FATA.
Following are the key epidemiological characteristics of polio cases reported in 2015:
• 18 (81.8%) polio cases are younger than two years (median age: 13.5 months).
• Based on recall of parents, four (18.2%) cases did not receive any OPV dose (through routine vaccination and/ or campaigns); three (13.6%) cases received 1-3 OPV doses, four (18.2%) received 4-6 doses; while 11 (50%) polio cases received 7 or more OPV doses.
• Ten polio cases had date of onset of paralysis in January, ten in February and two in March.
It is worth mentioning that, Pakistan has reported less than one third of wild poliovirus cases this year as per point in time comparison with 2014. Khyber Pakhtunkhwa 40.9% (9/22) and FATA 27.3% (6/22) together reported 68.2% (15/22) wild polio cases in 2015 as compared to 92.6% (63/68) in 2014 at this point in time. No wild polio case have been reported from North Waziristan agency and South Waziristan agency reported only one case this year so far as compared to 73.3% (50/68) polio cases last year for the same time. These findings indicates that the main decline in wild poliovirus cases this year are attributed to these regions of the country. Khyber agency alone reported 22.7% (5/22) of the total wild polio cases so far this year as compared to one case in 2014.
Peshawar contributed 55.5% (5/9) of the wild polio cases reported this year from Khyber Pakhtunkhwa. Moreover; the two environmental sampling sites in Peshawar have also the presence of WPV-1 in five of six samples collected this year for which the results are available. This indicates that, Peshawar district remains the key polio reservoir in 2015. One out of eight environmental samples collected so far this year from Dera Ismail Khan in Khyber Pakhtunkhwa has been reported positive for WPV-1.
The situation in Karachi has been extremely concerning where 23 out of 29 wild polio cases of Sindh province reported from nine towns in 2014. Fortunately, no wild poliovirus case has been reported so far this year from Karachi. However, all the three environmental sampling sites in Karachi have shown the presence of wild poliovirus in sewage water samples indicating continuous WPV circulation. Wild poliovirus cases reported from Qambar, Dadu, and Sukkur districts; along with the positive environmental samples from Hyderabad, Sukkur and Jacobabad districts in Sindh indicates widespread circulation of WPV and substantial immunity gaps across interior Sindh.
Balochistan province did report 25 wild poliovirus cases in 2014 after an interval of 23 months; of which 19 (76%) cases were reported from Quetta Block (Killa Abdullah, Quetta and Pishin districts). Furthermore, WPV-1 was continuously present in the environmental samples collected from Quetta and Killa Abdullah in 2014. This year, Balochistan reported three WPV-1 cases so far (one each from Killa Abdullah, Quetta and Loralai districts), while no sewage water sample has been turned positive for WPV after January 2015 indicating notable improvement in Quetta Block.
No poliovirus case have been reported so far in 2015 from Punjab. However, WPV-1 has been detected in two out of 15 environmental samples collected this year from five sites of Lahore. WPV-1 has also been detected in one out of six environmental samples collected from the two sites in Rawalpindi. No WPV positive environmental sample has been reported from Multan this year, while environmental samples collected from Faisalabad district have been negative for WPV after 3rd January 2013. In the capital territory of Islamabad, one sample collected in January has been turned positive for wild poliovirus, out of the total three environmental samples for which the results are available so far in 2015.