Trichinella, IgG antibodies

Why this test?

To determine whether a person has been infected with trichinella.

In what cases is it prescribed?

The test is prescribed if: 

• symptoms of the disease appear,
• increased number of eosinophils, 
• increased level of some muscle enzymes,
• a sick person ate half-raw meat. 

Symptoms of the disease in the first 10 days: stomach ache, nausea, diarrhea.

Symptoms of trichinellosis 2-3 weeks after infection: muscle pain, fever, weakness, swelling (on the face, in particular around the eyes), red dots under the nails or on the surface of the eyes.

Test information 

Trichinella is a genus of parasitic roundworms. Several of their species are dangerous for humans. Trichinella parasitize humans and many animals (pigs, bears, rats, foxes, etc.). At the same time, trichinella larvae (in the form of cysts) are present in the muscles of the infected animal. If a person eats such meat, he can become infected with trichinellosis. As a rule, the most dangerous pork and meat of wild animals. 

To prevent contamination, it is necessary to carefully cook meat. At the boiling temperature of water, 100 ° C, trichinella are guaranteed to die. However, it is important to ensure that the products are fully heated (both outside and inside). Animals also become infected by eating meat.

Therefore, trichinellosis mainly occurs in carnivores. Pigs are often infected by contact with rats. Trichinella larvae in meat are surrounded by a dense capsule called a cyst. When the cysts enter the stomach, their membranes dissolve under the action of gastric juice. The larvae are released, penetrate the small intestine and after 1-2 days turn into adult sexually mature worms. 

After mating, the females produce a new generation of larvae that pass through the intestinal wall and spread throughout the body. Inside the skeletal muscles, the larvae are surrounded by a capsule, which is then impregnated with calcium salts and hardens (turns into cysts). Then the cysts are stored in the muscles indefinitely and wait for the next owner. The adults themselves do not live in the intestine permanently. Males die after mating, and females disappear 3-5 weeks after infection (due to the body's immune response). 

The severity of the disease depends on the number of trichinella that have entered the human body. Often, if there were few parasites, there are few symptoms. Trichinellosis occurs in two stages. The first is characterized by signs of an intestinal disorder: moderate abdominal pain, nausea, diarrhea. They appear in the first days after infection and disappear after 10 days (or earlier). It is at this time that the development of trichinella larvae begins in the small intestine. Symptoms of the second stage appear 2-3 weeks after infection and persist for several weeks. 

At this time, the larvae spread throughout the body, which disrupts the work of blood vessels and muscles. This can be accompanied by muscle pain, fever, weakness, swelling (on the face, in particular around the eyes), red dots under the nails or in the eyes. Sometimes trichinella damage the heart muscle, which causes heart pain, tachycardia. 

Disorders of the nervous system occur in rare cases, with severe infection. From the second week after infection, the number of eosinophils (eosinophilic leukocytes) in the blood increases and the concentration of muscle tissue enzymes (creatine kinase, lactate dehydrogenase) increases. In some cases, a muscle biopsy is used to diagnose trichinellosis. If there are many trichinella, their cysts can be detected under a microscope. 

After trichinella enter the human body, he begins to fight them. One of the ways to fight is the production of antibodies (special immunoglobulin proteins). There are five main types of immunoglobulins: IgG, IgM, IgE, IgA and IgD. IgE are antibodies that are involved in the immune response against parasitic worms. They appear at an early stage after infection with trichinella. However, there have been cases of trichinellosis when the IgE test was negative. Therefore, antibodies of this type are not suitable for diagnosis. The most suitable antibodies are IgG. They are present in the blood in the largest amount (compared to other types of immunoglobulins). With trichinellosis, IgG can be detected in the blood 12-60 days after infection (the stronger the infection, the earlier antibodies appear). 

The level of IgG remains high for a long time (months and years).