Drakunkulez: causes, symptoms, diagnosis, treatment

Drakunkulez - biogelmintoz. Sexually mature specimens are localized in the subcutaneous tissue, often the lower extremities.

The cycle of development of dracunculiasis

Drakunkulez - biogelmintoz. The ultimate host is a man, sometimes animals: dogs, monkeys. Intermediate hosts are freshwater crustaceans of the genus Cyclops or Eucyclops.

A person becomes infected with dracunculiasis, swallowing with water cyclops infested with mature larvae (microfilariae). In the gastrointestinal tract, cyclops are digested. Larvae penetrate the intestinal wall and migrate through the connective tissues towards the lower extremities. 3 months after the invasion, the female is fertilized. After that, the female migrates to the subcutaneous tissue of the lower limbs, grows, reaching a length of 75-100 cm. About a year after the penetration of the larvae, up to 3 million larvae form in the womb of the human body. The cephalic end of the female reaches the skin, causes a blister on it to form up to 5-8 cm in diameter, filled with liquid. The larvae exit the genital tract of the female through the rupture of the uterus and the walls of the helminth body near its anterior end. They are removed from the body of the final host through an opening formed on the skin by the secretion of special glands located at the anterior end of the helminth female. The small rhabdite-shaped larvae with a long filiform end have a length of 0.5-0.75 mm, a width of 15-25 μm.

When in contact with water, the bubble bursts. The front end of the female protrudes from it. The ejection of larvae from the body of rishta occurs due to a reduction in its musculature when it comes into contact with water, which may be due to the cooling of the front end of the helminth under the action of water. Within 2-3 weeks, the female "generates" up to 3 million larvae into the water. After that, the females die. They dissolve or calcify.

Larvae caught in water live in it for 3-6 days and are swallowed up by cyclops, in their body they grow, develop, double shed and reach the invasive stage after 12-14 days at a temperature of 25-30 ° C.

The maximum lifespan of a parasite in the human body is less than 18 months.

Epidemiology of dracunculiasis

Drakunculosis is common in countries with hot and arid climate, in tropical regions of Africa, in the south of the Arabian Peninsula, in southern Iran, in Pakistan, India, China, South America.

The foci of dracunculiasis are formed in areas where the population uses raw water for drinking from small artificial or natural inaccurate water bodies, into which the inhabitants go barefoot (at this time the female rishta spawn into the water of the larvae). The development of parasites occurs synchronously in all invasive people. Females are able to give birth to larvae simultaneously at almost all helminth carriers. This achieves a sharp increase in the likelihood of infecting a huge number of cyclops, and then final hosts for a short period of time. This feature of the development cycle has adaptive significance in zones with arid climate and rare rain periods. In the outbreaks of dracunculiasis, a large number of people are affected by this helminth during a short time interval.

The infection with dracunculiasis occurs as a result of accidental ingestion of cyclops by drinking water from standing open water bodies. In the human body, the parasite develops very slowly. The period of epidemiological incubation (the time that has elapsed from the moment of infection until the moment of allocation of larvae to the external environment) with dracunculiasis is very large and is 12 months or more. The invaded final host becomes a source of infestation only a year after infection.

The main source of infection is the infected person.

Dracunculiasis is spread in connection with unsanitary conditions, poor water supply, lack of water supply and sanitation. Drakunkulosis prevails in poor families living in uncomfortable homes and drinking raw dirty water, using feces for fertilizing vegetable gardens.

A large role in the contamination of water by larvae of rishta is played by water-carriers that go barefoot into standing water reservoirs for water intake, as well as the believing population performing ritual ablution in water bodies. As a result of the receipt of a large number of larvae, the presence of numerous cyclops and due to the habit of the population to drink raw water, the intensity of transmission of infestation in the foci of dracunculiasis is great.

The pathogenic effect of rishta is associated with sensitization of the body with products of helminth exchange, mechanical damage to tissues and attachment of a secondary infection.

[1], [2], [3], [4],

What causes dracunculiasis?

The causative agent of dracunculiasis is Dracunculus medinensis, rishta, with pronounced sexual dimorphism. The filiform female is a large nematode 30-129 cm long, 0.5-1.7 mm wide, male 12-30 mm long, 0.2-0.4 mm wide.

The posterior end of the male is bent to the ventral side. It contains 4 pairs of preanal and 6 pairs of postanal papillae, 2 dark-brown spicules 0.49-0.73 mm long and 0.2 mm long rolls. At the rounded anterior end of the female there is a quadrangular cuticular elevation with 4 double marginal papillae and the amphids located behind them. The mouth has a triangular shape, the short esophagus consists of the muscular and glandular parts, separated by a constriction located at the level of the nerve ring. The esophagus passes into the cylindrical intestine, ending with the anal opening near the posterior end of the body. The tail end of the female ends with a subulate appendage that is ventrally oriented. The vagina, located in the middle of the body, leads to two uterus, lying one after another. They open the oviducts, coming from the tubular ovaries. Females are vivacious.

In the process of prolonged development in the body of the final host (11-13 months), the primary cavity of the female is almost completely filled with uterus full of embryos. The opening of the vagina, the rectum and the opening of the vulva atrophy. The remaining part of the intestinal tube wrinkles and is pushed aside. The larvae exit through the lacerations of the uterus and the cuticle at the anterior end of the body.

Symptoms of dracunculiasis

Patients are informed about the presence of rishta a few months after infection, 8-10 days before the formation of a blister on the skin. The first symptoms of dracunculiasis are accompanied by severe allergic reactions. There are itching, hives, nausea, vomiting, asthmatic phenomena, fever, swelling of the joints, near which are helminths.

Soon after the rupture of the bladder, allergic phenomena cease. The further course of the invasion is determined by the absence or presence of a secondary infection.

Specific signs of this disease are erythema, skin tightening, the formation of vesicles and ulcers at the site of the helminth's release to the surface. The first symptoms of dracunculiasis are the formation of a small capsule, which turns into a bubble. The bubble is filled with a transparent yellowish liquid, which contains rishta larvae, leukocytes, lymphocytes and eosinophils. The formation of the bladder is accompanied by itching and burning pain, which can weaken from cold water. The bubble bursts in contact with water, the front end of the female protrudes from it. In place of the bladder, an ulcer appears, surrounded by a puff of swollen skin and covered with a white necrotic mass, which is discarded after a few days. In uncomplicated cases, the ulcer heals quickly. If there is only one helminth in the body, clinical manifestations last no more than 4-6 weeks and end with recovery. Local lesions are localized mainly on the shins and in the ankles (90%), sometimes found on other parts of the body: on the back, abdomen, scrotum, buttocks, mammary glands, tongue, shoulders.

Symptoms of dracunculiasis depend on the localization of the parasite. A more severe course of dracunculiasis is observed when the rishta is localized in the area of large joints, with parasite death, with secondary bacterial infection, or a combination thereof. Single lesions occur more often, but cases of parasitization in one person up to 50 helminths are known. The process is painful and deprives the patient of working capacity for a long time. Sometimes there is a loss of helminth before the hatching of the larvae. In these cases, the symptoms of dracunculiasis are absent.

Complications of dracunculiasis

When the rishta is localized in the joint area, acute arthritis develops, which in 1% of cases ends with ankylosis. The process can involve other large joints and muscles. Penetration into the site of the localization of the parasite of a bacterial infection can cause purulent abscesses, phlegmon, sometimes gangrene, epididymitis, orchitis, sepsis. The cases of tetanus, recorded in the dracunculiasis endemic areas, arise as a result of previous invasion of rishta. In the absence of complications, the prognosis is favorable.

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Diagnosis of dracunculiasis

Diagnosis of dracunculiasis in endemic foci in the presence of characteristic skin manifestations is not difficult. Under the skin, a cordlike formation is felt. At the site of the rupture of the bladder, one can detect the front end of the rishta and its larvae. Calcified parasites are found during X-ray examination.

Outside the endemic foci, differential diagnosis of dracunculiasis from furunculosis, abscess, phlegmon is necessary, and the patient should be able to stay in the foci of dracunculiasis.

[6], [7], [8], [9], [10], [11],

Treatment of dracunculiasis

Traditional treatment of dracunculiasis is wrapping a helminth body on a stick, several centimeters a day, avoiding its clipping. In the development of allergic phenomena, antihistamines are prescribed. Apply metronidazole at a dose of 250 mg x 3 x 10 days, for children - 25 mg / kg in three divided doses, the total daily dose should not exceed the dose of adults. Preparations do not destroy the helminth, but facilitate its extraction in the traditional way.

How to prevent dracunculiasis?

The global program for the eradication of dracunculiasis includes:

• providing the population with safe drinking water;
• the allocation of special reservoirs for the abstraction of drinking water and its protection from pollution;
• filtration of water from open, inactive reservoirs to prevent penetration of cyclops into it;
• identification and treatment of patients;
• prevention of insemination of reservoirs by helminth larvae by applying a dressing to the rishtoid bladder.