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.
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.
What is the history and life cycle of trichinosis?
The life cycle of this particular parasite is important in the way disease develops in humans. In 1835, J. Paget and R. Owen first discovered larvae of
Trichinella in a piece of human muscle during an autopsy. That same year, R. Virchow and F. Zenker discovered the complicated lifecycle of
Trichinella by feeding a dog Trichinella-infected meat.
In humans, the larvae are ingested, released from an encapsulated (encysted) cyst by stomach acid (except for the nonencapsulated
T. pseudospiralis), and then develop into adult male and female worms in the gastrointestinal tract. The adult worms mate and then shed larvae that penetrate the gastrointestinal tract and reach the bloodstream and lymph drainage system. The larvae are then distributed to body cells (mainly skeletal muscle cells). Some skeletal muscle cells develop into nurse cells that support and protect the larvae from the host's immune system. For a more complete description of the life cycle that requires at least two hosts, please see http://www.dpd.cdc.gov/dpdx/HTML/Trichinosis.htm with further details and photographs.
How is trichinosis diagnosed?
There are no good tests for the early phase of infection of the intestines. The history from the patient telling the doctor that he or she ate raw or undercooked meat could be the first clue. Unfortunately, most patients 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 in patients that have a history of eyelids swelling, pain, tenderness, and swelling in muscles, especially skeletal muscles and small hemorrhages (bleeding into tissues) under the fingernails and the conjunctivae of the eye that resemble splinters that occur a few weeks after eating raw or undercooked meat from pork or wild animals. Other laboratory findings that are elevated, but not specific for trichinosis, are creatine kinase, and lactate dehydrogenase, two 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 increases can also occur in other parasitic infections.
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.
Diarrhea is a change is the frequency and looseness of bowel movements. Cramping, abdominal pain, and the sensation of rectal urgency are all symptoms of diarrhea. Absorbents and anti-motility medications are used to treat diarrhea.
Nausea is an uneasiness of the stomach that often precedes vomiting. Nausea and vomiting are not diseases, but they are symptoms of many conditions. The causes of vomiting differ according to age, and treatment depends upon the cause of nausea and vomiting.
Itching can be a common problem. Itches can be localized or generalized. There are many causes of itching to include: infection (jock itch, vaginal itch), disease (hyperthyroidism, liver or kidney), reactions to drugs, and skin infestations (pubic or body lice). Treatment for itching varies depending on the cause of the itch.
Although a fever technically is any body temperature above the normal of 98.6 degrees F. (37 degrees C.), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 degrees F (38 degrees C.). Fever is part of the body's own disease-fighting arsenal: rising body temperatures apparently are capable of killing off many disease- producing organisms.
Vertigo is a feeling of spinning movement, and at times accompanied by nausea and vomiting occur. Vertigo is most often associated with an inner ear problem. The treatment for vertigo can be lifestyle changes and medication if necessary.
Food poisoning is common, but can also be life threatening. The most common form of food poisoning is caused by bacteria and include symptoms such as fever, abdominal pain, diarrhea, nausea and vomiting.
Epilepsy is a brain disorder in which the person has seizures. There are two kinds of seizures, focal and generalized. There are many causes of epilepsy. Treatment of epilepsy (seizures) depends upon the cause and type of seizures experienced.
Myocarditis is an inflammation of the heart muscle and can be caused by a variety of infections, conditions, and viruses. Symptoms of myocarditis include chest pain, shortness of breath, fatigue, and fluid accumulation in the lungs. Treatment mainly involves preventing heart failure with medication and diet, as well as monitoring for heart rhythm abnormalities.
Seizures are divided into two categories: generalized and partial. Generalized seizures are produced by electrical impulses from throughout the brain, while partial seizures are produced by electrical impulses in a small part of the brain. Seizure symptoms include unconsciousness, convulsions, and muscle rigidity.
Travelers should prepare for their trip by visiting their physician to get the proper vaccinations and obtain the necessary medication if they have a medical condition or chronic disease. Diseases that travelers may pick up from contaminated water or food, insect or animal bites, or from other people include malaria, meningococcal meningitis, yellow fever, hepatitis A, typhoid fever, polio, and cholera.