Trichinosis (Trichinellosis)

  • Medical Author:
    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

How is trichinosis diagnosed?

There are no accurate tests for the early phase of infection of the intestines. The history of eating raw or undercooked meat could be the first clue. Unfortunately, most people infected do not seek physician help during the relatively short intestinal phase. During the muscle phase of the disease, a presumptive clinical diagnosis can be made with a history of eyelid swelling, pain, tenderness, swelling in muscles, small hemorrhages that resemble small splinters under the fingernails, and the conjunctivitis of the eyes. These symptoms occur a few weeks after eating the raw or undercooked meat from pork or wild animals. Other blood tests that are elevated, but not specific for trichinosis, are creatine kinase, and lactate dehydrogenase (enzymes that increase in the blood when muscle cells are damaged or destroyed). Also, a particular type of white blood cell, eosinophils, are usually increased several times their normal concentration after the muscle phase starts, but eosinophil count increases can also occur in other parasitic infections and allergies.

More specific tests (indirect immunofluoresence, latex agglutination, enzyme-linked immunosorbent assays) are available that detect antibodies developed by the infected person's immune response to the parasites. However, these tests may not be positive until three or more weeks after infection and may be falsely positive in patients with infections with other parasites or autoimmune diseases. The best test for trichinosis is a biopsy of muscle that shows larvae in the muscle tissue. In general, biopsies are done infrequently and the diagnosis is based on presumptive clinical findings, patient history, and associated blood tests outlined above. In addition, trichinosis often occurs in outbreaks (a number of infections occurring at about the same time). For trichinosis, outbreaks occur when a number of people eat infected meat from the same source. For example, in 2007, over 200 patients were diagnosed with trichinosis in Poland when a meat-processing plant sold Trichinella-contaminated pork to customers. Knowledge of the source of an outbreak can help identify and diagnose individuals that may be exposed to the parasites; it can also allow the source of the infections to be eliminated.

Medically Reviewed by a Doctor on 9/8/2016

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