Loiasis: causes, symptoms, diagnosis, treatment

Loalosis is a transmissible biohelminthosis. Sexually mature individuals parasitize in the skin, subcutaneous tissue, under the conjunctiva of the eye and under the serous membranes of various human organs. Larvae (microfilariae) circulate in the blood.

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Loallose development cycle

The infection of a man with loalosis occurs through the bite of the flies of the genus Chrysops. Loalosis - biogelmintosis, in the cycle of its development there are final hosts - man, monkeys, and intermediate - blood-sucking flies of the genus Chrysops.

The ducks live in areas of densely shaded slowly flowing water bodies. Females lay eggs on the leaves of aquatic plants. Larvae develop in water, coastal mud, and moist soil. Bites of horseflies are painful. With bloodsucking, they absorb up to 300 mg of blood, in which there may be several hundred larvae. Microfilariae undergo a developmental cycle in the pectoral muscles of the horsefly in the same way as the larvae of the vuherries in mosquitoes, and after 10-12 days reach the invasive stage. Invasive larvae migrate into the oral apparatus of the horsefly. When the blind man bites a person, invasive larvae migrate to the surface of the skin and after a bite they get into the blood. The flies can transmit the larvae to the final host for 5 days.

After 1.5-3 years, microfilariae reach puberty and begin to spawn living larvae. Sexually mature individuals migrate through the subcutaneous connective tissue. Microfilariae born by the female on the lymphatic and blood vessels penetrate into the lungs and accumulate there. Periodically, they migrate to the peripheral blood vessels. Microfilariae circulate in the blood only during the day, and therefore they are called Microfilaria diurna (daytime microfilariae). The greatest number of larvae in the peripheral blood is observed between 8 and 17 hours.

In the process of evolution, there have been mutual adaptations in the cycle of helminth development associated with the vital activity of the carriers.

Carriers (flies) are intermediate hosts. They are active during the day, therefore in the peripheral blood of the final host at this time is the largest number of larvae.

The life expectancy of adult helminths ranges from 4 to 17 years.

Epidemiology of Loallosis

Endemic foci are found in forest zones of West and Central Africa from 80 ° N. N. Up to 50 ° S. W. Loaoz is common in Angola, Benin, Gambia, Gabon, Ghana, Zaire, Cameroon, Kenya, Congo, Liberia, Nigeria, Senegal, Sudan, Tanzania, Togo, Uganda, Chad and others.

The source of the spread of loalosis is sick people. Specific carrier of loalosis are the dolphins, capable of transmitting the pathogen at the bite.

The incubation period of loalosis lasts for several years, but sometimes it is reduced to 4 months. Microfilariae can be detected in peripheral blood 5-6 months after infection.

Pathogenic effect is due to sensitization of the human body to the products of metabolism and decay of helminths. Active movement of the filaria (at a speed of 1 cm per minute) causes mechanical damage to the tissues, itching

What causes loalosis?

Loalosis is caused by the "African eye worm", Loa loa, has a white translucent filamentary body. The cuticle of helminths is covered with numerous rounded protuberances. Females have a length of 50-70 mm, a width of 0.5 mm, males of 30-34 mm and 0.35 mm, respectively. The caudal end of the male is bent to the ventral side and has two spicules unequal in size. Adult helminths are able to actively migrate through the subcutaneous connective tissue, penetrating, in particular, into the conjunctiva.

Microfilariae have a barely visible case; their length is 0.25-0.30 mm, width is 0.006-0.008 mm. The nuclei reach the apex of the pointed tail end.

Symptoms of Loallosis

Loalosis begins with allergic manifestations. Characteristic initial symptoms of loalosis: pain in the extremities, hives, subfebrile temperature. The course of the disease can be asymptomatic until the helminth penetrates the conjunctiva into the eyeball. There can be edemas of the eyelids, retina, optic nerve, pain, conjunctival hyperemia, visual impairment. Because of the defeat of the eyes, this helminth is called an "African eye worm".

An important symptom of loalosis is the development of Calabar edema. It appears on limited areas of the body, slowly increases in size and slowly dissolves, the skin over it is of ordinary color. When pressing on the edematous area of the hole does not remain. Edema occurs in places of localization of filarias in the skin and subcutaneous tissue, most often they appear in the areas of wrists and elbow joints. The localization of edema is impermanent. The appearance of edema can last several years. Edema can cause pain, disrupt the functions of the organs, accompanied by pruritus, subfebrile temperature, skin rashes.

On the part of the blood there is eosinophilia, anemia; there is also an increase and fibrosis of the spleen.

Migration of helminths in the urethra causes severe pain, especially during urination. Due to the violation of outflow of lymph in men can develop hydrocele.

The penetration of larvae into the capillaries of the brain causes its focal lesions, the development of meningitis and meningoencephalitis. The defeat of the central nervous system can lead to death.

The course of the disease is prolonged, with alternating exacerbations and remissions. The prognosis of uncomplicated loalosis is favorable.

Complications of Loallosis

Neuritis, meningoencephalitis, retinal detachment, abscess development, laryngeal edema, endocardial fibrosis, frequent complications in endemic region residents according to loalosis.

Diagnosis of Loallosis

Differential diagnostics of loalosis with other filariasis is necessary .

Laboratory diagnosis of loalosis is associated with the detection of larvae in smears and a thick drop of blood. Blood is taken at any time of the day. In endemic areas, the diagnosis is often made on the basis of clinical symptoms (the presence of "Calabar edema", eosinophilia). Under the conjunctiva, the helminths are visible to the naked eye. In the case of lalocephalic encephalitis, microfilariae can be detected in the cerebrospinal fluid. Sometimes they use immunodiagnostics.

Treatment of lojalosis

Treatment of loalosis is carried out in a hospital. Apply diethylcarbamazine according to the same scheme as with vucererioze. Considering the expressed allergization of the body by the products of helminth disintegration, antihistamines or glucocorticoids are simultaneously prescribed.

From the conjunctiva eyes helminths are removed surgically.

How to prevent loalosis?

Personal prophylaxis of loalosis is to protect against the attack of horseflies: wearing tight clothes, using repellents. Public prevention of loalosis - identification and treatment of patients, vector control, cleaning of river banks from shrubs inhabited by hives, draining and insecticide treatment of wetlands for the destruction of larvae of horseflies