Trichinellosis in children: causes, symptoms, diagnosis, treatment

Trichinellosis is an acute febrile disease caused by the roundworm Trichinella. It is accompanied by muscle pain, facial swelling, various skin rashes, hypereosinophilia of the blood, and in severe cases - myocarditis, focal lung lesions, and meningoencephalitis.

ICD-10 code

B75. Trichinellosis.

Epidemiology

Trichinellosis is widespread. The main endemic foci of trichinellosis are Belarus, the North Caucasus, Lithuania, and Georgia. In recent years, endemic foci of trichinellosis have begun to recover in the central regions of Russia and Ukraine, which is associated with the development of individual pig farming. In Belarus, the North Caucasus, and Lithuania, foci have a mixed synanthropic (natural)-endemic nature with a constant exchange of invasion between domestic and wild animals. In endemic foci, the main source of invasion is pigs, in nature - wild boars, bears, badgers. In the north, there is a circulation of invasion between polar bears, arctic foxes, rodents, and marine mammals.

Outbreaks of trichinellosis are explained by the consumption of infested, insufficiently heat-treated meat, corned beef, sausages that have not undergone sanitary and veterinary control. If infested meat is not consumed simultaneously or evenly, an outbreak or group disease can last up to a month, sometimes more. Infested products are often transported to different parts of the country. In case of massive infestation, children are the first to fall ill.

Causes of trichinosis

The causative agent is the nematode Trichinella spiralis. Three variants of the helminth pathogenic for humans have been described: T. spiralis, T. nelsoni and T. nativa. The species independence of the variants has not been definitively established.

A mature female Trichinella is up to 1-3 mm long, a male is 1-2 mm long. The parasites are located in the mucous membrane of the small intestine, partially hanging into its lumen. After fertilization of the females, the males die. After 2-3 days, fertilized females begin to lay larvae, which penetrate the blood and lymphatic vessels of the intestinal mucosa and through the portal vein system and the thoracic duct enter the blood and lymph flow. Partially lingering in the parenchyma of the internal organs, they settle in the striated muscles. Depending on the intensity of the invasion, the females remain in the intestine and produce larvae for 3-6 weeks. In the skeletal muscles, 3-4 weeks after the invasion, a connective tissue capsule with a gradually forming internal hyaline layer is formed around the larvae. The encapsulated larva has an oval ("lemon-shaped") shape measuring 0.5x(0.2-0.6)x0.3 mm. The capsule is gradually impregnated with calcium salts, and the larvae can remain invasive for many years.

Pathogenesis of trichinosis

Trichinella larvae are released from the capsule under the action of gastric juice. In the small intestine, the larvae penetrate the surface layer of the mucous membrane, develop to sexual maturity, the females are fertilized, being partially in the lumen of the intestine. The larvae actively penetrate the blood and lymphatic vessels, are carried by the blood and lymph flow throughout the body, lingering in the myocardium, lungs, liver and skeletal muscles.

Symptoms of trichinosis

The incubation period of trichinellosis is from 1 to 4-6 weeks. In the case of a malignant course of the disease, it is reduced to 1-3 days. The incubation period of up to 5-6 weeks occurs when infected with northern natural strains of trichinella.

Trichinellosis in children, under equal conditions of infection, proceeds relatively easier than in adults. The most striking symptoms of trichinellosis - fever, muscle pain, swelling of the face - are expressed relatively weaker in young children than in schoolchildren. However, in young children, lymphadenopathy with enlarged pharyngeal tonsils and sore throat, enlarged spleen - it is soft, slightly painful on palpation - is noted. In cases of severe course, there is a bright exudative or erythematous, hemorrhagic rash.

Diagnosis of trichinosis

Trichinellosis is diagnosed:

• based on the epidemiological history - consumption of raw or insufficiently cooked pork, wild game meat, lard, sausages, home-made canned food 1-6 weeks before the appearance of clinical signs of invasion, acute febrile illness with pronounced allergic manifestations (swelling of the face, myalgia, skin rash, pulmonary syndrome, hypereosinophilia of the blood);
• based on the results of laboratory testing - detection of Trichinella larvae in meat using trichinelloscopy or the method of digestion in artificial gastric juice.

If it is impossible to examine meat, serological reactions with trichinellosis diagnosticum (RSK, RIGA, IFA) provide significant assistance. They become positive already at the end of the 2nd week after infection. In doubtful cases with single diseases, it is sometimes necessary to resort to muscle biopsy (gastrocnemius, deltoid, broad back muscles) with subsequent histological examination and muscle digestion to detect larvae.

Treatment of trichinosis

Mebendazole (Vermox) is prescribed at a dose of 5 mg/kg per day, in 3 doses after meals for 5-7 days. For severe abdominal pain, dyspeptic disorders, No-shpa, papaverine, and B vitamins are given.

Forecast

The prognosis for moderate trichinellosis is favorable, with severe course of the disease is determined by the speed of diagnosis and complex specific and pathogenetic treatment. In case of malignant trichinellosis, recovery can only be ensured by complex specific, pathogenetic and rehabilitation therapy from the first days of the disease.

Prevention of trichinosis

Includes sanitary and veterinary control of meat products, sausages, canned meat, stall keeping of pigs, prohibition of their slaughter in the backyard, feeding carcasses of wild animals to pigs. Deratization in houses and outbuildings, prevention of access of wild rodents to pigsties are of importance. Meat or corned beef should be boiled in pieces no more than 2.5 cm in diameter for 3 hours. Prevention of the spread of trichinellosis is achieved by destruction (burning) of infested meat and urgent notification of the patient to the territorial sanitary and epidemiological station (SES), followed by examination of the population and elimination of the consequences of the invasion. Persons who consumed infested meat are given preventive treatment with vermox at a dose of 5 mg / kg in 3 doses for 5-7 days depending on the intensity of meat infestation.