What is Gnatostomiasis?

Gnatostomiasis is a zoonotic natural-anthropurgic biohelminthiasis from a group of nematodoses with a fecal-oral mechanism of transmission of the pathogen. It is characterized by polymorphic and clinical manifestations.

There are about 1,000 cases of gnatostomiasis in humans. Diseases were found mainly in Thailand, as well as in India, Indonesia, Myanmar, Malaysia, the Philippines, Japan, China, Bangladesh, Israel. The disease is characterized by natural foci. Sick inhabitants of endemic coastal areas, regardless of belonging to any of the population groups.

Causes of Gnatostomiasis

The causative agent of gnatostomiasis is a small or medium-sized nematode Gnathostoma spinigerum, a parasite of the vertebrate digestive tract. After development in water at a temperature of 27 – 31 ° C, the larvae emerge after a few days, which are swallowed by freshwater cyclops crustaceans, cyclops are swallowed by reservoir hosts (fish, frogs, birds) in which the larvae form cysts.

Gnathostoma spinigerum larvae cause in humans eosinophilic meningitis, migrating skin edema, eye damage, and damage to internal organs.

Pathogenesis during Gnatostomiasis

A person usually becomes infected by drinking non-disinfected water, meat from fish, frogs, and birds. Infection through the skin is also possible.

The natural susceptibility of people has not been established. The duration of the incubation period has not been established.

When a person infects through the stomach wall, the parasite’s larvae migrate to the liver, and then they are introduced into the subcutaneous tissue and other organs and tissues. Therefore, the clinical manifestations are diverse and depend on the localization of the parasite. The most frequent manifestations of invasion – creeping rash, subcutaneous nodes, migrating edema and abscesses. Of the deepest disorders, gastrointestinal and cerebral are most characteristic.

Symptoms of Gnatostomiasis

Clinical manifestations are usually associated with the migration of a single larva to the skin, internal organs, the central nervous system or the eyeball. During migration, there may be local inflammatory reactions, pain, cough, hematuria, accompanied by fever and eosinophilia. With skin lesions appear painful and itchy migrating edema; distal extremities and eyelids are particularly often affected. Manifestations usually disappear after a week, but often recur for many years. Damage to the eyeball is a danger to vision. CNS lesion is manifested by eosinophilic meningitis with encephalomyelitis. This severe complication is due to the migration of larvae along the nerve trunks and inside the CNS. Attacks of excruciating radicular pain, paresthesia of the trunk and extremities, followed by paraplegia, are characteristic. Damage to the brain with focal hemorrhages and necrosis often ends in death.

Diagnosis of Gnatostomiasis

Detection of migrating edema in the background of severe eosinophilia in combination with an appropriate epidemiological history usually makes it possible to diagnose gnatostomiasis. However, damage to the eyes and the central nervous system can develop without prior skin manifestations. In the latter case, in the study of CSF eosinophilic cytosis, blood or xanthochromia are detected. However, helminth larvae in it almost never happens.

Treatment of Gnatostomiasis

The best way to diagnose and treat at the same time is the surgical removal of the parasite from the subcutaneous tissues and eyes; unfortunately, it is rarely feasible. Albendazole is sometimes effective (400-800 mg / day by mouth for 21 days). With CNS damage, symptomatic treatment is recommended, usually involving glucocorticoids.

Prevention of Gnatostomiasis

In unfavorable areas, only boiled water is allowed to be consumed and heat treatment of the tissues eaten in the reservoirs of the parasite’s hosts is obligatory. Immunoprophylaxis measures are not developed.

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