Ascariasis

Ascariasis - helminthiasiscaused by Ascaris.
Roundworm roundwormsRoundworm (Ascaris lumbricoides) - roundworms, which reaches a length: female 25-40 cm, males 15 - 25 cm (Fig.). Adult ascarids live in the small intestine, where the females lay daily up to 200 000 eggs. Eggs with excrement fall into the environment, where under favorable conditions ripen. Mature egg contains the inside of the sliding larva. Development of eggs lasts from 15 days to several months, depending on temperature and humidity of the soil. At hit of Mature eggs in the human intestine larvae are released from egg shells and implemented in the intestinal Vienna, which fall into the portal, and then into the inferior Vena cava and the right heart. Through the pulmonary trunk they pass into the capillaries of the bronchioles, where are moving in the Airways. Using cilia mertzatelnogo epithelium bronchi they reach the mouth, and mingling with the saliva, back into the small intestine where they develop into adult parasites. Migration lasts 14 to 15 days; the development of Ascaris (from the moment of getting the eggs in the gut before it appeared in the faeces eggs of the next generation) lasts 2,5-3,5 months; roundworm live not more than one year.
Ascariasis is distributed everywhere, except for the zone of permafrost, deserts and semi-deserts. The optimum temperature for development of eggs roundworm 24 degrees. Low temperatures slow down the development, but do not kill the eggs. They can survive during the winter period and can live in the soil for several years. The Ascaris infection occurs as a result of introduction of a Mature egg from the soil in the mouth with dirty hands or consumption of vegetables, fruits and berries, contaminated eggs. Of great importance in the spread of ascariasis is fertilizer gardens no untreated faeces. Eggs can get on household items and food with dust, and recorded in accommodations on the soles of shoes. The infection usually has a seasonal character and is more common in summer-autumn period. Ascariasis is observed mainly in children; adults is less common, due, apparently, immunity acquired in the result of multiple infections.
Larvae of Ascaris sensitized body products of their metabolism and decay, as well as mechanical damage blood vessels and tissues during migration.
Clinically there are early and late phases of ascariasis. The early phase is connected with the migration of larvae and is the development of skin rashes, liver lesion (granulomas) and education eosinophilic volatile infiltrates in the lungs. Can also develop bronchitis and focal pneumonia. For late, intestinal, phase characteristic diarrhoea disorders, headaches, irritability, restless sleep. Complications intestinal phase can be bowel obstruction, perforated peritonitis, penetration Ascaris in the liver and respiratory tract. The diagnosis of an early phase of ascariasis is based on the results of immunological reactions with the antigen of Ascaris, late phase - detection of eggs in feces; sometimes roundworm found in the gut by x-ray.
Treatment usually salts piperazine (piperazine-adipate, and others). The preparation is administered for 2 consecutive days in a daily dose: adults and adolescents over 15 years - 3-4 g, children up to 1 year - 0.4 g, 2-3 years - 0.6 g, 4-6 years - 1 year, 7 - 9 years 1.5 g, 10-14 years - 2 g Daily dose given in 2 reception at intervals of 1.5-2 hours.
Prevention of ascariasis: disposal of faeces; the treatment of the population in endemic zones piperazine not less than 2 times a year; personal hygiene; deep cleaning of boiled water, vegetables, berries, fruits.

Ascariasis (ascaridosis) is a disease caused by parasitic in humans and some animals roundworms (nematodes) - Ascaris. Human parasites Ascaris lumbricoides and in very rare cases In mystax and Toxascaris leonina.
Ascaris lumbricoides-bisexual nematodes (Fig. 1); length female 25 - 40 cm, males 15-25 cm; the fusiform body, reddish. The female lays a day over 200 thousand eggs released from the intestines of a person with faeces. These eggs have not contagious. Located in them the germ must develop to the infective larvae. Development of eggs in the external environment and under favorable conditions (temperature 24-26°, moist soil, oxygen and others) takes 24-25 days. The eggs of Ascaris can perezimovali in the external environment. In the complete absence of moisture or direct sunlight they quickly die. Human infection ascariasis happens if swallowed Mature roundworm eggs containing infective larvae. In the intestines larva prosurvival mucous membrane, reaches in venous vessels and blood flow is logged in the right half of the heart and capillaries of the lung artery (Fig. 2). Provorova their wall, the larva penetrates into bronchioles, and from there to the bronchi, trachea and throat. Getting into his mouth, larvae can be swallowed with saliva. The development of Ascaris from larvae to the first clutch of eggs lasts 9-15 weeks.

Fig. 1. Roundworm: left - male; on the right is a female.
Fig. 2. Roundworm larva in the lung.

Epidemiology. Ascariasis is widely distributed in zones of moderate and warm climate. Ascariasis of local origin is not found in polar, sub-polar regions, permafrost zones, deserts and highly arid areas. Source askaridoze invasion is man; the pigs do not play a serious role in the epidemiology of ascariasis. Children mostly infested more often than adults, and more intensively, that, apparently, due to the presence of adults acquired immunity and no children hygiene practices. The main factors of transmission of ascariasis - soil, vegetables, in a lesser degree, fruits and other food products, as well as water and dirty hands. The role of flies in the transfer of ascariasis void.