Toxocarosis - easy to catch, hard to suspect

Which specialist can suspect this disease? The answer is quite ambiguous: infectious disease specialist, surgeon, primary care physician, paediatrician, gastroenterologist, neurologist and even... oculist! Today we will talk about parasites - toxocaras, whose biological features give them the ability to affect almost any human organ.

Toxocarosis is a parasitic disease of humans, the original source of which is animals of the dog family. The role of dogs in the development of the disease is proven, and there is a debate among scientists about cats, but nevertheless, they should not be forgotten.

The infection process begins when an animal becomes ill. Then a sexually mature female toxocara starts laying a huge number of eggs in its body. The life span of the female is from 4 to 6 months, and she can lay about 200 thousand eggs daily, which averages 30 million eggs over her lifetime. And this is only one individual... This number of parasites determines the prevalence of toxocarosis: among dogs, the infection rate varies from 0 to 93% - on average 15.2%, almost every 10 dogs (depending on the environmental conditions, the colder it is, the lower the percentage). The probability of finding toxocariasis in soil ranges from 1 to 60%; antibodies to toxocariasis are found in 2 to 14% of people.

A huge mass of eggs is excreted through the intestines of the animal and enters the soil. The eggs reach their new host, humans, by various routes. This can happen if hygiene rules are not observed - toxocaras are swallowed together with soil particles both directly and, for example, through unwashed vegetables. Thus, 4 risk groups can be distinguished:

• Children (due to lack of knowledge about hygiene).

• Workers in contact with soil and animals: veterinarians, workers of municipal structures, drivers and car mechanics (possibility of contact with soil particles when servicing cars), sellers of vegetable shops....

• Owners of vegetable gardens, pets, particularly dogs; hunters.

• Persons who do not always have the opportunity to observe the rules of hygiene due to the peculiarities of residence, working conditions, habits.

It is worth noting that humans are a dead-end branch of the life cycle of toxocariasis. In the human body, they cannot pass from the larval stage to a sexually mature individual and continue their lineage. Consequently, the disease is not transmitted from person to person.

After ingestion, larvae emerge from the eggs in the small intestine and pass through the intestinal wall into the bloodstream. The larvae first enter the liver, then the right side of the heart, then the blood carries them through the lungs to the left side of the heart, after which the toxocaras spread throughout the body. In which organ they get "stuck" depends on the diameter of the blood vessel (larvae are 0.02 mm in diameter). Having chosen an organ, toxocaras begin to prepare a habitat for themselves: they create a capsule that cannot be damaged by immune cells.In the capsule, larvae can exist for months and years, poisoning the body with the products of their vital activity. Sometimes the capsule ruptures, then the larvae begin to migrate within the organ or re-enter the bloodstream....

Another feature of these parasites is their ability to pervert the work of the immune system - the immune system can start working against your body, or a person gets various allergies.

Symptoms of toxocarosis.

The clinical picture depends on the number of parasites that have entered the body and the organ in which they are located.

In the acute stage of the disease, symptoms similar to a cold are found chills, fever, malaise. There may be signs of bronchitis or pneumonia. Sometimes there are symptoms of inflammation of the pancreas (abdominal pain) or liver. If the pathogen gets into the muscle tissue, muscle pains appear. If the brain is affected - headaches, sleep disturbances, general weakness, seizures, and even paralyses!

After the acute stage of the disease subsides, the disease takes a chronic type of course. Bright manifestations are not observed, but during this period the affected organs slowly suffer, the propensity to allergies increases.  As soon as a person's immunity weakens, the disease "flares up" in the most unexpected places.

Special attention is paid to eye lesions - microscopic examinations of eyeballs that were removed for medical reasons were conducted - in 88 cases out of 245 toxocar larvae were found (35.92%)! According to the medical journal "Treating Doctor", ocular toxocarosis is the leading cause of vision loss. Almost all parts of the eye can be affected, therefore, any abnormalities in visual function can potentially be considered as manifestations of toxocarosis.

And so, the main indications for toxocarosis screening are:

- Prone to allergies;

- unexplained visual impairment;

- ineffectiveness of standard treatment of diseases of internal organs;

- a general decline in health, weakness, fatigue;

- being in a risk group.

Features of diagnosis

Diagnosis of this disease is difficult due to the lack of specific symptoms, so suspect toxocarosis can be suspected when the standard treatment of a disease is ineffective.

Due to their biological characteristics, toxocar larvae are not detected in feces. Microscopic detection of the parasite by examination of organ fragments (biopsy) allows 100% diagnosis. However, the procedure is quite painful and there is no probability that the organ fragment under examination will contain the parasite.

OLYMP СDL offers a modern ELISA method for diagnosing toxocarosis based on the detection of specific antibodies to the pathogen. The method has a number of advantages:

- reliability

- specificity (this particular pathogen is detected)

- possibility to observe the dynamics of the disease by antibody counts

- low price

- short time of readiness of the results in the treatment room

- no contraindications

Toxocarosis testing is available at any branch of the OLYMP branches of laboratories.

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Toxocarosis helminths parasites