"Wall"ing Off Disease.

• Position: MEDICINE & HEALTH

There are three aspects to the caravan: what is shown by the media; what is there to be seen; and what remains unseen.

The locus is on innocent children, as in the widely circulated photograph of an obese woman with two children lacking pants or shoes, purportedly fleeing tear gas sprayed by cruel law enforcement agents. They are far from home, in a very dangerous place, in violation of the laws of Mexico. If that were a U.S. citizen, would Child Protective Services accuse her of child abuse and neglect, and take the children into foster care?

Thousands of migrants are crammed together and about one-third of them are sick. Without sanitation, outdoors in the rain, many more will become ill. Several cases of tuberculosis, chicken pox, and HIV have been reported.

The unseen travelers also include measles, Chagas disease, hepatitis, and many other dangerous microbes. You can see the lice that serve as vectors of diseases, such as typhus, if you look closely. Workers in migrant reception centers have spent hours combing nits out of little girls' hair--but they could be fired for talking about it.

Then there is that mysterious polio-like illness--AFM for acute flaccid myelitis--that has struck hundreds of U.S. children. Some would be in "iron lungs" if we did not use a different kind of breathing machine today. AFM first was noted in 2014, just coincidentally in time and space with the dispersal of thousands of Central American children into U.S. schools. More prominent at that time was an outbreak of a deadly respiratory illness that sent hundreds of American children to intensive care units. Both types of symptoms probably can be caused by enterovirus D68, which happens to be endemic in Central America. Is there a connection? The Centers for Disease Control and Prevention claims not to know.

Chagas disease (American trypanosomiasis) afflicts around 8,000,000 people in Central America. An early symptom is to awaken with swelling of the eyelids on one side that persists for weeks, but most do not know they have Chagas until it destroys the muscles of their esophagus, colon, or heart. It is carried by the reduviid ("kissing") bug, already present in the U.S. Packrats are hosts to these bugs. A high rate of Chagas is being found in dogs in Texas.

Many migrants have latent tuberculosis, which can become active at any time. What happens if a case of active tuberculosis is diagnosed in the U.S.?--all of the patient's contacts must be identified...