Riezenman contacted the Texas Department of Health, which in turn alerted the national Centers for Disease Control, in Atlanta. CDC officials knew that anencephaly, although rare, occurs naturally at a rate of around three or four per 10,000 live births in the United States. A cluster of five cases, in Brownsville, a city of around 100,000, could be a statistical anomaly, but perhaps nothing more than that. Few were prepared for what the CDC found: that in 1989 and 1990 (and continuing up to the present) Brownsville and surrounding Cameron County had an incidence of anencephaly five times the national average. Which leads inevitably to the question: how much longer could this have gone on before someone noticed?
The answer to that question, in turn, depends on what the CDC finds has been in on in Brownsville. It has looked into several possible explanations for the outbreak, including diet–specifically, a deficiency of folic acid, which is a suspected risk factor for anencephaly and the related condition of spina bifida–and a fungal contamination of the food supply. Brownsville is heavily populated by Mexican-Americans, whose starchy diet is low in the fresh vegetables that are the main source of folic acid. The corn in their tortillas is susceptible to infestations of mold. But to a number of Brownsville’s health workers, the prime suspect is as obvious as the nearby Rio Grande, from which Brownsville gets its water–and into which pours untreated waste from the large Mexican city of Matamoros, home to scores of factories taking advantage of cheap labor, favorable tariffs–and Mexico’s lax enforcement of environmental laws.
“We live here and we know about the accidents that occur in Matamoros,” says Gregoria Rodriguez, who is working on a study of the birth defects at the Brownsville Community Health Center. “The maquiladoras”–Yankee-owned plants that make electronic products, auto parts and plastics in the border cities"use all sorts of solvents irresponsibly and discharge their wastes irresponsibly." Because cross-border pollution has been an issue in the proposed United States-Mexico free-trade agreement, which is strongly backed by the Bush administration, some in Brownsville suspect the CDC was intentionally downplaying environmental factors in its study. " The environment," says Dr. Carmen Rocco, a pediatrician with the health center, " wasn’t even a hypothesis that was being considered."
CDC officials dispute this. Investigators did take blood and urine samples from the 28 mothers they were able to track down and question for the study and tested them for exposure to a limited number of hazardous chemicals. They did not, however, test air, water and soil samples directly. Earlier this year Rocco formed a committee to do that testing, and two weeks ago the Environmental Protection Agency, prodded by Texas’s senators, announced a study of pollution and health all along the Rio Grande Valley. If pollution is implicated in the anencephaly outbreak, it would be a frightening development. But it would resolve at least one worry for mothers like Teresa Salazar, 29, who assumed she was at fault after doctors discovered (through ultrasound) that she was carrying an anencephalic fetus last year. On her doctors’ advice, she terminated the pregnancy, her third after two miscarriages. “I felt very guilty. I told my husband to go away so he could have children [with someone else],” she says.
The EPA study will take two years; the CDC study in Brownsville, which was originally scheduled to be released as a draft in April, has been put off until July. Meanwhile, says Stuart Shalat, an epidemiologist at Texas A&M, all we know for sure is that “something bad is happening in the lower Rio Grande Valley.” We don’t know what’s causing it. We don’t know how long it went on before a coincidence brought it to the attention of health authorities.
And, most alarming of all, we don’t know where else along the border-or elsewhere-it might be happening.
