The three-year long civil war in Syria, which has claimed an estimated 150,000 lives, has come to affect the infants and children of the region in a new way. From the start, bombs and chemical weapons brutally harmed many kids as well as adults, but now young ones are at risk from something new: the spread of infectious diseases.

With the war-related deterioration of the government’s ability to provide even rudimentary services, the vaccination of infants can no longer reliably be performed. Thus, starting last summer, cases of measles and—most disturbingly—polio among unvaccinated children were identified in Syria.

Now, a case of polio has been diagnosed in Iraq and many others are certain to follow. The UN has labeled this the greatest polio-related challenge in history—an observation that’s hard to argue with, even using the WHO’s possibly (very) watered down numbers.

The epidemiology of polio is simple to understand—as simple as seeing the inevitability of the major crisis we have before us. Polio is an enterovirus (lives and is replicated in our intestines) that is spread via fecal-oral transmission. Vaccination in infancy prevents acquisition by introducing killed (Salk) or live, weakened (Sabin) virus in the first few months of life. It’s preferably given at 2, 4, and 6 months of age, just as the newborn’s antibody, passively acquired from the mother during fetal life, begins to fade. (The Sabin versus Salk debate is one of the great arguments in modern medical history and will not be recapitulated here). Once vaccinated, an immunologically normal person will remain protected for life.

However, wars destroy not just the provision of vaccination, but also the electricity needed to maintain the refrigerators that vaccine is stored in, as well as the plumbing that assures clean, non-polio contaminated water to drink. Especially in a war that drags on for months into years, the risk of contracting the disease soars. As anyone old enough to remember the American polio days, or more recently, as readers of Philip Roth’s last great novel, Nemesis, learned, in the U.S., children pre-vaccine were cautioned to stay away from swimming holes or any trace of possibly contaminated food or water. Or people.

The extra caution makes some sense. Unlike what is seen clinically with some equally contagious illnesses, like measles, with polio, at least a third of those infected remain completely well—contagious to be sure, but not infectious. Thus, the time-honored approach of separating the sick from the well is unlikely to prevent spread.

Plus, with measles, a sick person has to be near a non-immune person, not miles downstream (as can occur with polio). Fecal-oral transmission means just that: ingesting excrement. In an unplumbed world, people defecate into the same river or pond as others drink from. Therefore, live viruses may enter the water supply and spread a disease like polio rapidly through a city or village.

Indeed, the worry about the sewer system has lead to a unique disease surveillance program in Israel where viruses are searched for in the sewers of the main cities. A recent finding that wild-type (the virus from nature, not from the lab in the form of the weakened Sabin vaccine strain) was circulating in Israeli sewers led to an immediate decision to redouble vaccination efforts in the Israeli young.

Finally, the polio that is circulating in Syria and now Iraq is related to the strains that are found in infected children from the three countries having ongoing endemic spread: Pakistan, Afghanistan, and Nigeria. Each of these countries shares a specific civil issue: either overt war or profound distrust by some communities of others in the country. In Pakistan, for example, as I wrote recently in a Daily Beast article praising Croatia’s federal pro-vaccination stance, a Pakistani lawyer claimed in 2012 that “these vaccines are meant to destroy our nation…The [polio] drops make men less manly, and make women more excited and less bashful. Our enemies want to wipe us out.” Worse yet, polio vaccinators have been murdered in Pakistan and elsewhere for trying to save lives.

The new polio threat is a major and predictable consequence of war, just like shrapnel injuries and broken families. The disease will not spread outside war-torn or impoverished areas and into suburbs in the United States—our governmental and societal will, though so often ridiculed, is far too strong to allow such a calamity. We are protected here because our government actually is effective.

In contrast, the vision of a child permanently crippled by a completely preventable disease may become the most durable image of the Syrian Civil War, irrefutable evidence not just of ancient, geologic hatreds but also of a truly failed government.