A study by health experts in Los Angeles and at the U.S. Centers for Disease Control has focused attention on a rare but potentially fatal infection by a tapeworm whose larvae can invade the brain and other organs.
The disease, called cysticercosis, afflicts mostly immigrants from Latin American countries, especially Mexico.
Cysticercosis is considered an important, yet underreported, disease in Los Angeles and in other regions along the U.S.-Mexican border, according to a report in today's issue of the Journal of the American Medical Assn.
The organism that causes cysticercosis is a tapeworm that normally lives in pigs but also occurs in humans in two different stages of its development, an adult stage and a larval stage. The adult stage seldom causes symptoms, but humans who are infected by it become carriers who excrete the tapeworm eggs in feces. Other individuals may consume the eggs in water or food that has been contaminated with feces.
As the eggs develop into an adolescent stage in the intestines, they invade the skin, brain, eye, muscle, heart, liver and other tissues.
Symptoms of cysticercosis include seizures, headache, abnormal behavior, difficulty in moving about and abnormal sensations. The disease is sometimes treated with a drug that kills the organism and occasionally with surgery to remove it from the brain.
The researchers, headed by Dr. Frank O. Richards of the Centers for Disease Control, identified 497 cases of cysticercosis--95% involving Latinos--that were treated at four Los Angeles hospitals between 1973 and 1983. Eleven of the patients died. The hospitals were Martin Luther King Jr. General Hospital, County-USC Medical Center, Harbor-UCLA Medical Center and Childrens Hospital of Los Angeles.
The researchers found a steady rise in the number of such cases since 1977, which they attributed to the increasing number of immigrants from Latin America, especially Mexico, where the illness is said to be responsible for 9% of all hospital admissions for a neurological examination.
The study, the first of its kind, was undertaken to get a better idea of the disease's incidence, according to Frank J. Sorvillo, an epidemiologist with the Los Angeles County Department of Health Services.
"It is more common than we expected," he said in an interview.
The report said heightened awareness of the illness by local physicians and the availability of the X-ray computed tomography scanners, which enable doctors to detect the presence of the organism in brain and other tissues, have combined to make diagnosis of the disease more common.
In Los Angeles--in contrast to developing countries, where tapeworm-contaminated pork is common--the probability of acquiring cysticercosis is low, according to the report. Nevertheless, 12 cases of the disease were identified in native U.S. citizens who had no record of foreign travel.