Tapeworm infections of the brain, which can cause epileptic seizures, appear to be increasing in Mexico and bordering southwestern states, Loyola University Health System researchers report.

In Mexico, up to 10 percent of the population may have the infection, neurocysticercosis. While many people never develop symptoms, neurocysticercosis nevertheless "remains a serious health concern, especially among the poor," Loyola researchers wrote in the journal Neurological Research.

Their article is among several articles in the journal's April issue that describe neurological infections in Latin America. Guest editor is Dr. Jaime Belmares, assistant professor in the Division of Infectious Diseases, Loyola University Chicago Stritch School of Medicine.

Neurocysticercosis is caused by a tapeworm found in pigs called Taenia solium. A person can get infected with the parasite by eating undercooked pork. That person then can excrete tapeworm eggs. The contamination spreads through food, water or surfaces contaminated with feces. A person can become infected, for example, by drinking contaminated water or putting contaminated fingers in the mouth.

Neurocysticercosis is most common in poor rural communities in developing countries with poor sanitation and hygiene and where pigs are allowed to roam freely and eat human feces.

Once inside the stomach, the tapeworm egg hatches, travels through the bloodstream and ends up in the muscles, brain or eyes. The worm, which can grow to more than one-half inch long, becomes enveloped in a fluid-filled cyst. Cysts in the muscles generally don't cause symptoms. But cysts in the eyes can cause blurry vision, while cysts in the brain can cause headaches, encephalitis and seizures. Less common symptoms include confusion and difficulty with balance.

Seizures occur in up to 70 percent of patients. "They're pretty dramatic," Belmares said. "Every seizure needs to be properly evaluated."

The article on neurocysticercosis was written by Dr. Adolfo Ramirez-Zamora, a former resident at Loyola now at the University of California at San Francisco and Tomas Alarcon, who did a rotation at Loyola during medical school.

Other articles in the April issue of Neurological Research describe other neurological infections in Latin America, including Chagas disease, hydatid disease of the central nervous system, neuroschistosomiasis, meningococcal disease and rabies.