Sir: Pakistan along with Afghanistan remain the only two countries where polio is still categorised as an endemic viral infection. As of October 2015, there have been 38 documented cases of wild poliovirus in Pakistan in the past one-year. Pakistan had the largest number of polio cases in 2014 and as of October 2015, it has maintained this record. Polio is actually a viral infection that paralyses body parts. It is a contagious disease and transfers from one person to another through the blood transfusion. It attacks the immune system and, thus, one cannot fight against it. There are different types of viruses, which attack different body parts. The WHO estimates that 65 to 75 percent of the polio cases in developing countries occur amongst children under the age of three years while 95 percent of all cases occur amongst children below five years. WAQAS AHMED Karachi