Today we are seeing another cruel method of warfare emerge on the battlefield: the weaponization of disease, particularly in Syria and Yemen.

Targeting health care facilities during conflict has occurred before. But unlike the attacks on hospital ships during World War I, or even sporadic attacks in more recent conflicts, the pace of attacks on health facilities, workers, and resources in Syria and Yemen is massive and unrelenting.

In the past three years, combatants in these conflicts have actively targeted health and humanitarian facilities and indiscriminately decimated civilian infrastructure. Hospitals are out of service. Clinics have been destroyed. Water treatment plants have been turned to rubble. Vaccines and other lifesaving drugs have been intentionally blocked from reaching civilians.

All of this has created public health catastrophes — a massive cholera outbreak in Yemen, and new outbreaks of once-vanquished diseases like polio and measles in Syria and Yemen. These put millions of children at risk for death and illness.

My organization, Physicians for Human Rights, has mapped the systematic attacks on hospitals, clinics, and other medical facilities in Syria. Our data show that, since 2011, there have been a staggering 477 attacks on medical facilities, as well as the deaths of 820 medical personnel. Nine out of 10 of these attacks were launched by the Syrian government or its Russian allies. Each of these strikes puts essential medical care further out of reach for thousands of sick and injured Syrians.

None of the conflict’s belligerents have acknowledged that their actions are purposefully creating a public health disaster. In fact, after launching a lethal chemical weapons strike in April, the Syrian government then brazenly struck the hospital where survivors were being treated. There have been few, if any, substantive consequences for these blatant violations of international law.

Such attacks have dire consequences. For each doctor killed or clinic destroyed, an untold number of patients suffer. As hospitals, clinics, and water treatment and sanitation facilities have become targets, civilian survivors of bombs or bullets or poison gas have fallen victim to previously controlled infectious diseases.

Take, for example, the recent polio outbreak in eastern Syria. It started when an oral form of the live polio vaccine mutated. Abysmal sanitation helped it spread through the population. Children who hadn’t been vaccinated against polio contracted the crippling and potentially deadly virus. It’s a perfect epidemiological storm, enabled by warfare.

In Yemen, the targeting of hospitals, clinics, water treatment plants, and sanitation facilities has caused the largest cholera outbreak in the world, with 5,000 new infections every day. To date, more than 200,000 people have been infected, and 1,300 have died. All parties to the conflict share responsibility, as combatants on all sides — including the Saudi coalition using U.S.- and European-made arms — have attacked the country’s health infrastructure. Such targeting has also paved the way for a measles outbreak in Yemen.

Cholera and measles, both preventable and treatable diseases, prey on the vulnerable. With 1.5 million children facing malnutrition in Yemen, both of these diseases may ultimately claim an unconscionable number of young lives.

There are many signs of hope and humanity in both Syria and Yemen. Despite a lack of pay and protection, thousands of health workers are making incredible sacrifices to identify individuals who need medical help and provide whatever treatment is available. The World Health Organization, UNICEF, Doctors Without Borders, and other international organizations are making headway in efforts to broaden vaccination and treatment.

We must not make the mistake of thinking of these deaths and illnesses as collateral damage of war. They are not accidental, and the destruction of medical and sanitation infrastructure is part of a cruel, illegal, and intentional strategy.

As the world acknowledged two decades ago in the Balkans and Rwanda, wars aren’t just waged on the battlefield with bombs and bullets. And even though modern warfare is insidious and battlefields are sometimes uncertain, the laws of warfare still apply.

That means there must be independent investigations of violations of international law when it comes to targeting health and humanitarian resources. There must also be regular and public reporting of incidents at the United Nations Human Rights Council and Security Council. We must recognize and prosecute these acts as war crimes, specifically as violations of the Geneva Convention.

Hundreds of thousands have already died in Syria and Yemen. And without accountability and clear condemnation from the international community, millions more lives are at stake.PBS