Trypanosomiasis

Description:

The African trypanosomiasis of the person known also as a tsetse-fly disease, is a transmissible parasitic disease. Parasites are the protozoa belonging to the sort Trypanosoma. They are given to people at stings of tsetse flies (sort Glossina) which get an infection from the people or animals infected with these pathogenic parasites of the person.

Tsetse flies are found only in Africa to the South from the Sahara, but only its certain types tell a disease. For the reasons inexplicable today in many areas where tsetse flies are found, there is no tsetse-fly disease. Villagers of areas, where there is a transmission of infection, going in for agriculture, fishery, livestock production and hunting, are most subject to stings of a tsetse fly and, therefore, a disease. The disease develops in areas which sizes vary from one village to the whole area. Within separately taken infected area intensity of a disease can vary between different villages.

Trypanosomiasis symptoms:

The disease, is generally transmitted at stings of the infected tsetse fly, but there are also other ways of infection of people with a tsetse-fly disease.

    * Transmission of infection from mother to the child: trypanosomes can get through a placenta and infect a fruit.
    * Mechanical transfer through other blood-sicking insects is possible. However it is difficult to estimate epidemiological impact of such transfer.
    * In laboratories cases of inadvertent infection result from a prick with the infected needle.

At the first stage of a trypanosome breed in hypodermic fabrics, blood and a lymph. This stage is known as a hemolymphatic phase of which fever attacks, a headache, a joint pain and an itch are characteristic.

At the second stage parasites get through a blood-brain barrier and infect the central nervous system. This stage is known as a neurologic phase. In general, at this stage the most obvious symptoms and symptoms of a disease appear: changes of behavior, confusion of consciousness, touch frustration and lack of coordination. Disturbance of a cycle of a dream which gave the name to this disease is an important sign of its second stage. In the absence of treatment the tsetse-fly disease is considered deadly.

Trypanosomiasis reasons:

The African trypanosomiasis of the person has two forms depending on a species of a parasite:

    * Trypanosoma brucei gambiense (T.b.g.) meets in the Western and Central Africa. This form of which more than 95% of all registered cases of a tsetse-fly disease are the share now results in persistent infection. The person can be infected for several months or even years without manifestation of any considerable signs or symptoms of a disease. Symptoms often appear already at a late stage of a disease of the patient when his central nervous system is surprised.
    * Trypanosoma brucei rhodesiense (T.b.r.) meets in East and South Africa. Now this form of which less than 5% of the registered cases are the share, causes an acute infection. The first signs and symptoms appear in several months or weeks after infection. The disease develops quickly and affects the central nervous system.

One more form of a trypanosomiasis meets, mainly, in 21 Latin American countries. It is known as the American trypanosomiasis, or a Chagas disease. Its activator is other species of protozoa other than activators of the African form of a disease.

Treatment of the Trypanosomiasis:

The type of treatment depends on a disease stage. The drugs used at the first stage are less toxic and it is easier to accept them. The earlier the disease is revealed, the it is better than treatment perspective.

Success of treatment at the second stage depends on medicine which can get through a blood-brain barrier and reach parasites. These drugs are toxic and it is difficult to accept them. For treatment of a tsetse-fly disease four drugs which are provided to developing countries free of charge are registered.

Treatment at the first stage:

    * Pentamidine: it is open in 1941, it is used for treatment of a tsetse-fly disease of T.b. gambiense at the first stage. Despite existence of undesirable effects which should be taken into consideration drug, in general, is well transferred by patients.
    * Suramin: it is open in 1921, it is used for treatment of T.b. rhodesiense at the first stage. It makes a certain undesirable impact on urinary tract and causes allergic reactions.

Treatment at the second stage:

    * Melarsoprol: it is open in 1949, it is used at both forms of an infection. It is derivative arsenic and causes numerous undesirable side reactions. The heaviest of them is reactive encephalopathy (an encephalopathic syndrome) which can come to an end with a lethal outcome (3% - 10%). In some centers, especially in the Central Africa, growth of stability to this drug is observed.
    * Eflornitin: this substance, less toxic, than меларсопрол, was registered in 1990. It is effective only against T.b. gambiense. The scheme of treatment difficult also does not allow any deviations.
    * Recently (in 2009) the combined treatment nifurtimoksy and eflornitiny is entered. It simplifies use of an eflornitin as monotherapy, but, unfortunately, it is not effective concerning T.b. rhodesiense. Нифуртимокс it is registered for treatment of the American trypanosomiasis, but not the African trypanosomiasis of the person. Nevertheless, after data acquisition of clinical tests about safety and efficiency this drug was accepted for use in a combination with eflornitiny and included in the List of the main medicines of WHO which provides it for this purpose free of charge.