The Center for Disease Control’s confirmation that Zika is causing microcephaly and other birth defects is a reminder that infectious diseases and their control are, in general, the big exceptions to the Iron Law that no intervention makes a difference. As Hans Zinsser writes in Rats, Lice, and History:
That form of parasitism which we call infection is as old as animal and vegetable life. In a later chapter we may have occasion to consider its origin; to this we have some clue from the new diseases which appear to be constantly developing as we begin to conquer the old ones. But our chief purpose in writing the biography of one of these diseases is to impress the fact that we are dealing with a phase of man’s history on earth which has received too little attention from poets, artists, and historians. Swords and lances, arrows, machine guns, and even high explosives have had far less power over the fates of the nations than the typhus louse, the plague flea, and the yellow-fever mosquito. Civilizations have retreated from the plasmodium of malaria, and armies have crumbled into rabbles under the onslaught of cholera spirilla, or of dysentery and typhoid bacilli. Huge areas have been devastated by the trypanosome that travels on the wings of the tsetse fly, and generations have been harassed by the syphilis of a courtier. War and conquest and that herd existence which is an accompaniment of what we call civilization have merely set the stage for these more powerful agents of human tragedy.
Zinsser wrote his book in 1935 as a “biography” mainly of typhus and its depredations through history. In a cruel irony, just a few years later, typhus was one of the main killers and chief actors in World War II. As Wikipedia summarizes:
During World War II typhus struck the German Army as it invaded Russia in 1941. In 1942 and 1943 typhus hit French North Africa, Egypt and Iran particularly hard. Typhus epidemics killed inmates in the Nazi Germany concentration camps; infamous pictures of typhus victims’ mass graves can be seen in footage shot at Bergen-Belsen concentration camp. Thousands of prisoners held in appalling conditions in Nazi concentration camps such Theresienstadt and Bergen-Belsen also died of typhus during World War II, including Anne Frank at the age of 15 and her sister Margot. Even larger epidemics in the post-war chaos of Europe were only averted by the widespread use of the newly discovered DDT to kill the lice on millions of refugees and displaced persons.
While my great-grandmother, who arrived in Auschwitz early in the war, before it was fully a death camp, most likely died of untreated diabetes, my great-uncle, who got there a few years later, as likely as not died of typhus. Here’s a relevant image from Maus 2, Art Spiegelman’s graphic memoir of his father’s survival of Auschwitz:
Typhus interacted with the other half of my family tree, as well; my maternal grandfather arrived in Naples in early 1944, immediately after it had been liberated from both fascists and typhus (and a few months before he lost a leg stepping on a mine on an Italian hillside a bit further north). As an AEI report on DDT’s use recounts:
In October 1943, Allied forces liberated Naples as they advanced northward through Italy. A typhus epidemic broke out shortly after the liberation, posing a significant threat to both troops and civilians. The U.S. military mixed DDT with an inert powder and dusted it on troops and refugees, to great effect. Public health expert Fred Soper noted that “a thorough application of 10 percent DDT louse powder to the patient, his clothing and bedding and to the members of his household will greatly reduce the spread of typhus in the community.”
Dusting stations were set up around the city, and in January 1944, two delousing stations dusted 1,300,000 civilians. Within three weeks of the dusting (along with other less important treatment and vaccination programs), the epidemic was under control. The number of civilian cases was halved in the first week alone. The Allies administered more than three million applications of DDT powder in Naples.
The Allies would go on to administer DDT as a delousing agent to millions of displaced persons and refugees, possibly preventing the wartime epidemic from becoming a continent-wide catastrophe.
Rachel Carson is of course a national hero (the lunchroom in the science museum where I had my first real job was named after her) for Silent Spring, which convinced the public and Congress to ban DDT and convinced international aid organizations not to fund DDT spraying in poor countries. (Whether Carson intended these policy consequences is a matter of debate.) Carson was a great nature writer (her earlier work The Edge of the Sea is a classic of “science as seeing“) and the environmental consequences of DDT she documented were by-and-large real; the beautiful view of two bald eagles swooping and diving to capture fish that I saw once from my friend’s house in Cape Breton could be attributed indirectly to her advocacy, I suppose. But I could live without that memory more easily than I could take care of a child born with microcephaly; one of the more likely consequences of climate change is an expansion of disease organisms’ range and their vectors’, and I am more confident of our ability to deploy DDT in a controlled way than of the efficacy of any future climate change agreement.