Pursuing Parasites in Meat
November 2, 2015
A Polish scientist is developing a fast and effective test to detect parasites in meat. Specifically, the test is for Trichinella parasitic worms and the Toxoplasma gondii parasite, which causes a disease called toxoplasmosis.
When eaten with meat, Trichinella worms and the Toxoplasma gondii parasite may cause fever, vomiting, muscle pain, and in some cases depression and schizophrenia. In extreme cases, they may lead to the patient’s death. They are difficult to detect because the tests routinely used for it are imperfect.
Toxoplasmosis tests are not normally performed in humans. Only with pregnant women do doctors administer tests for the presence of antibodies indicative of the patient’s prior contact with the parasite. Meat is not monitored for infection with Toxoplasma gondii.
With Trichinella, a diagnostic method used in slaughterhouses makes it possible to detect the parasite in meat. But the method is labor intensive and takes a long time, so scientists are looking for a faster and more effective route.
To determine if someone has been infected with Trichinella, it is necessary to examine the patient's blood for the presence of antibodies. The next step is muscle biopsy, but this is not always successful.
According to the scientist who is working on the new method—Anna Zawistowska-Deniziak, Ph.D., from the Polish Academy of Sciences’ Witold StefaŮski Institute of Parasitology in Warsaw—the traditional method is not only time-consuming, but it may be inconclusive: the muscle fragment collected in this way may not contain the parasite.
Zawistowska-Deniziak’s team is working to detect Trichinella and Toxoplasma gondii directly from the blood of people and animals. This will make it possible to diagnose pathogens without the need for expensive laboratory equipment and highly qualified personnel, Zawistowska-Deniziak says. The new method could also be applied when inspecting meat intended for human consumption. Zawistowska-Deniziak has received zl.80,000 from the Foundation for Polish Science under its Inter program for the first stage of her research project.
“We will collect blood from an animal and after two hours will be able to tell if it’s infected with the parasite,” Zawistowska-Deniziak says. “For now we will be conducting tests on animals, but we plan to use the same method in humans.”
Trichinella and Toxoplasma gondii cause many parasitic infections that can be contracted by eating infected meat, for example. About 100 people become infected with trichinosis, a parasitic disease caused by Trichinella roundworms, every year. To prevent this, meat should be subjected to appropriate heat treatment. However, some traditional and popular meat dishes in Poland are based on marinated, smoked, dried and raw meats, which invite parasites.
Most often trichinosis affects those who eat venison. In the first period of the invasion, the patient has a fever, vomiting, and gastrointestinal disorders. This is followed by muscle pains.
Pregnant women are among those vulnerable to being infected with toxoplasmosis. This is dangerous to the fetus. If the infection occurs during the first trimester of pregnancy, the result is usually miscarriage, and in subsequent trimesters the risk involves hydrocephalus or inflammation of the cornea. However, if a pregnant woman previously had such an infection, she has antibodies and the parasite will not be harmful.
“In the initial stage of the invasion, the parasite circulates in the blood and then reaches various tissues,” Zawistowska-Deniziak says. “When it reaches the brain, it may cause certain types of mental disorders. Some of those who suffer from such disorders have antibodies, which means they have had contact with the parasite. However, this relationship is still being researched.”