Linking pollution and infectious disease

Thousands of seals died along the coasts of the heavily polluted Baltic Sea in the late 1980s. Scientists traced the deaths to a virus similar to the one that causes distemper in dogs. Last year, the same virus struck hundreds of seals in Maine. In both instances, researchers believe that persistent organic pollutants, such as polychlorinated biphenyls (PCBs), dioxins, and furans, played an indirect role in the seals’ demise. The seals are one example of a phenomenon of increasing importance to toxicologists: the interplay between exposure to environmental contaminants and infectious disease. More than two decades ago, researchers reported that exposure to low levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic of the dioxins, decreases resistance to an influenza virus in mice (Fundam. Appl. Toxicol. 1996, DOI: 10.1006/faat.1996.0004). Scientists have since shown that exposure to other chemicals, including perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), mercury, and...