Sleeping sickness – as which activator the elementary sorts Trypanosoma act, and carriers - blood-sicking tsetse flies. The symptomatology of a sleeping sickness is characterized by education on the place of a sting of primary affect (a tripanosomny shankr), wavy fever, lymphadenitis, skin rashes, local hypostases, the increasing drowsiness, paralyzes, mental disorders, a coma. Diagnosis of a sleeping sickness is based on detection of trypanosomes in biological material (a punktata of a shankr, lymph nodes, blood, cerebrospinal fluid). Therapy of a sleeping sickness is carried out by medicines pentamidine, , , .
Sleeping sickness (African ) – the disease from group of inoculable tripanosomoz proceeding with fever, defeat lymphatic and the central nervous system. Allocate 2 forms of a sleeping sickness: Gambian (West African) and Rhodesian (East African) the tripanosomoza caused by different types of activators. The sleeping sickness is endemic for 36 countries of tropical Africa where disease carriers - tsetse flies are found. The largest epidemics of a sleeping sickness were recorded in 1896-1906, 1920 and 1970. Annually on the African continent 7-10 thousand new cases of a sleeping sickness are registered. Most the disease is widespread among the villagers who are engaged in agriculture, livestock production, fishery or hunting. Except the African tripanosomoz, constitutes danger to the person American (Shagas's disease).
Reasons of a sleeping sickness
Two morphologically identical types of the causative agent of a sleeping sickness of the person are known: Trypanosoma brucei gambiense causing a Gambian form and Trypanosoma brucei rhodesiense causing the Rhodesian form of the African tripanosomoz. Parasites have the oblong and spindle-shaped, flat form, length of 12-35 microns and width of 1,5-3,5 microns. Both species of trypanosomes are transmitted through saliva during a sting of a tsetse fly (Glossina palpalis) which serves as a carrier of a disease and after infection is capable to transfer trypanosomes during all life. For infection of the person with a sleeping sickness one sting of an invazirovanny fly who allocates about 400 thousand parasites while the minimum invaziruyushchy dose makes 300-400 trypanosomes with saliva suffices.
At a krovososaniye of invazirovanny vertebrate animals or the person blood tripomastigota which breed by binary division in a gleam of intestines of a tsetse fly get to an organism of an insect. By 3-4 day tripomastigotny forms get into salivary glands where are transformed to epimastigota. In salivary glands epimastigotny forms undergo repeated division and complex morphological changes therefore turn into the metacyclic tripomastigota representing an invasive stage of trypanosomes. At a repeated sting together with saliva the tsetse fly enters under skin of the person metacyclic tripomastigota which in several days get into blood and a lymph, are carried on an organism, turning into blood tripomastigota.
After a sting of the infected fly in the place of entrance gate local and inflammatory reaction in the form of the painful itching shankr and regionarny lymphadenitis develops. In 1-3 weeks, after penetration of trypanosomes into blood and lymphatic system the haemo lymphatic stage of a sleeping sickness develops. The late (meningoentsefalitichesky) stage of the African tripanosomoz is caused by penetration of a parasite into TsNS. In response to an invasion the immune system reacts development of the specific antibodies of the class IgM allowing to constrain some time a parazitemiya. However high anti-gene variability of trypanosomes breaks formation of specific immunity, causing continuous progressing and the returnable and recidivous nature of a sleeping sickness.
Symptoms of a sleeping sickness
The early (gematolimfatichesky) stage of a sleeping sickness lasts about 1 year (sometimes from several months to 5 years). Approximately in a week after a sting of a tsetse fly on skin primary affect – a tripanoma, or tripanosomny , the representing painful eritematozny small knot with a diameter of 1-2 cm reminding a furuncle is formed. This element is most often localized on the head or extremities, izjyazvlyatsya quite often, however in 2-3 weeks usually spontaneously begins to live, leaving behind the pigmented hem. Along with formation of a tripanosomny shankr on a trunk and extremities there are spots of pink or violet color with a diameter of 5-7 cm (tripanida), and also face edemas, brushes, feet.
Further development of a sleeping sickness is connected with an exit of parasites in blood that is followed by developing of fever of the wrong type. The feverish periods with temperature peaks to 38,5-40 °C alternate with the apireksichesky periods. Increase in regionarny lymph nodes, especially zadnesheyny (Uinterbottom's symptom) which become dense is a characteristic sign of a sleeping sickness and can reach the sizes of pigeon egg. The current of a haemo lymphatic stage of a sleeping sickness is characterized by the increasing weakness and apathy, tachycardia, artralgiya, loss of body weight, increase in a liver and spleen. 30% of patients have urtikarny rashes on skin, develops the century swelled. Damage of an organ of vision in the form of a keratit, an iridotsiklit, hemorrhage in an iris, turbidity or scarring of a cornea is possible.
Duration of a haemo lymphatic stage of a sleeping sickness can make several months or years then the disease passes in late (meningoentsefalitichesky, or terminal) a stage. During this period to the forefront in a clinical current there are symptoms of an encephalomeningitis and a leptomeningit caused by penetration of a trypanosome through a hematoencephalic barrier and damage of a brain. As the most typical manifestation of the African tripanosomoz serves the increasing day drowsiness leading to the fact that the patient can fall asleep, for example, during food.
Progressing of a sleeping sickness is followed by development of atactic gait, the muffled speech (dizartriya), salivation, tremor of language and extremities. The patient becomes indifferent to the events, is slowed down, complains of a headache. Violation of the mental status in the form of depressive or maniacal states is noted. In the late period of a sleeping sickness spasms, paralyzes, the epileptic status join, the coma develops.
The Rhodesian form of a sleeping sickness has heavier and transient development. Fever and intoxication are expressed stronger, there comes exhaustion quicker, often there is a damage of heart (arrhythmia, myocarditis). Death of the patient can occur within the first year of a disease even before transition of a tripanosomoz to a meningoentsefalitichesky stage. As a cause of death of patients most often serve interkurrentny infections: malaria, dysentery, pneumonia, etc.
Diagnostics and treatment of a sleeping sickness
Preliminary diagnosis of a sleeping sickness is performed on the basis of kliniko-epidemiological data, as the most important of which serve stay in the endemic regions of Africa, existence of long, recurrent fever, primary affect, cervical lymphadenitis, hypostases, to drowsiness, etc. As the incontestable proof of infection with the African tripanosomoz serves detection of trypanosomes at laboratory researches of the native and painted according to Romanovsky-Gimz biological material. For the purpose of detection of a parasite blood, tserebrospinalny liquid can be exposed to the analysis a tripanosomny shankr, the changed lymph nodes.
In some cases for recognition of a sleeping sickness biological test with vnutribryushinny introduction of blood or cerebrospinal fluid painful to guinea pigs is carried out. From immunological reactions are applied by RIF, IFA. The Gambian form of a sleeping sickness should be differentiated with malaria, toxoplasmosis, limfogranulematozy, tuberculosis, meningitis, encephalitis, etc.; the Rhodesian form, besides, – with a typhoid, a septitsemiya.
Specific therapy of a sleeping sickness is most effective in an early stage, before development of cerebral symptomatology. At a Gambian form of a sleeping sickness at a haemo lymphatic stage it is appointed , pentamidine or ; at a meningoentsefalitichesky stage it is effective only . In the early period of the Rhodesian form of a sleeping sickness it is applied ; in late – . The dezintoksikatsionny, hyposensibilizing, symptomatic therapy is in addition carried out.
Forecast and prevention of a sleeping sickness
Without treatment the lethality from a sleeping sickness is close to 100%. In case of the beginning of specific therapy in an early stage of the African tripanosomoz perhaps absolute recovery; at late begun treatment the forecast is much worse. Except terms of an initiation of treatment, the outcome is influenced by a form of a sleeping sickness: at the Rhodesian option of a tripanosomoz the forecast is always more serious.
In prevention of a sleeping sickness the major role is played by destruction of tsetse flies by means of insecticidal medicines, cuttings down of shrubby thickets near settlements, use of individual protection equipment from stings of blood-sicking insects in the endemic regions of Africa. Mass chemoprophylaxis pentamidiny is carried out to the periods of epidemic outbreaks of a sleeping sickness among locals and visitors. Immunoprevention of the African tripanosomoz is not developed.