The polio-vaccine killings in Pakistan show that the country must fight the virus of extremism as well as the poliovirus.
Pakistan surrenders its security as killings thwart polio efforts
Pakistan is infected with two deadly diseases - one is polio; the other is extremism.
Poliovirus attacks a child's central nervous system, and can cause permanent paralysis within days of infection. The virus of extremism, on the other hand, attacks the mind, radicalises the victim, and ultimately paralyses the thought process, converting the patient into a human bomb. There is a vaccine against the poliovirus, but there is still no effective vaccine against extremism.
Tehrik-i-Taliban Pakistan has now claimed responsibility for the coordinated murders this week of mostly-female volunteers who had been administering polio vaccine to children in Karachi, Peshawar and elsewhere.
These acts of primitive brutality killed eight, but also put at risk the lives of innumerable children - and not only in Pakistan. The eradication of polio is a realistic goal - the disease, once endemic in 120 countries, is now self-sustaining in only three: Pakistan, Afghanistan and Nigeria.
But if the campaign to wipe out polio should fail, because of murders like these or for any reason, a rebound by the disease could, experts say, lead to as many as 10 million cases worldwide over the next 40 years.
But for now, at least, it is Pakistani children who are most at risk, especially an estimated 160,000 in North Waziristan and 80,000 more in South Waziristan. After this week's murders, the World Health Organization suspended its vaccination campaign in both Karachi and Peshawar - the second time this year security threats to vaccine providers forced that step.
Immunisation has been working. In the early 1990s, Pakistan had an estimated 20,000 new polio cases per year, but by 2005 the count of new cases had fallen to 30. But last year, the number rose to 198, and water samples disclosed that 108 districts of the country harboured the deadly poliovirus.
The propaganda against vaccination began in 2006 when a TTP leader, Mullah Fazlullah - known as "Mullah Radio" for his broadcasts from the one-time Taliban stronghold in the northwestern Swat Valley - denounced vaccination as a western plot to make Muslims sterile. He threatened anyone who dared to support the vaccinations.
Last June, despite the heartbreaking consequences for their own people, the Taliban outlawed polio vaccination in both Waziristans, as a way of protesting against US drone attacks.
Extremists clerics issued a number of fatwas against the vaccine. Taliban and other hardline religious groups portrayed immunisation as a western plot, calling the vaccine "George Bush's urine".
The militants depict all anti-polio workers as US-sponsored spies; a claim they must know cannot be true for all the Pakistani volunteers and medical professionals involved in the project.
Artfully, the Taliban has seized on one sliver of fact to discredit the campaign. Shakil Afridi is a Pakistani doctor who, working with US intelligence agents, visited Osama bin Laden's compound under cover of offering a vaccination against hepatitis. The ploy was apparently an attempt to get DNA confirmation of bin Laden's identity.
Hailed as a hero by many in the US, he was jailed for 33 years in Pakistan.
Ironically, Dr Afridi was not even offering polio vaccinations. But the slim link has been enough to help the Taliban discredit the polio project, in the minds of some ordinary people at least.
This week's attacks on polio volunteers drew condemnation from United Nations Secretary General Ban Ki-moon and from all around the world. And condemnation may not be all: the WHO may warn people to avoid travel to the country.
The Pakistani government has supported vaccinations, and has provided security for some vaccination teams in frontier areas, although not, until now at least, in Karachi.
These attacks put the government in a very awkward situation. The bitter truth about Pakistan is that the terrorists enjoy unrestricted independence to move and carry out their activities, even though the law enforcement agencies are supposedly in a state of high alert.
The country is now paying a heavy price for having a terrorist sanctuary in its tribal areas along Afghanistan border, as it faces the worst form of terror attacks on its own innocent citizens.
If it is to eradicate the poliovirus, it now seems, Pakistan will have to work harder to eradicate the virus of extremism and obscurantism, an infection that breeds the hatred, ignorance and illogic of what some call the "Talibanised mindset".
This will be a daunting challenge, as there is still no consensus in the country in support of robust, comprehensive military operations against Islamist extremists in North Waziristan, which is branded by the US as the global headquarter of Taliban and of Al Qaeda-linked militants.
Syed Fazl-e-Haider is a development analyst based in Pakistan