The Forms of Sleeping Sickness
How spreads sleeping sickness?
The host of the parasite is the tsetse fly, which can be transmitted to humans and other animals for their sting. The sting is painful and is usually noticed, but not all bites mean that you will get the disease. Then the parasite multiplies in the skin of the bite area and then enters the bloodstream and from there to the lymph nodes and central nervous system. The parasite reproduces (divided in half) in the blood and thus their number increases. When a fly bites an infected human or animal, can itself become infected and after a few weeks can in turn transmit the infection from their bites.
Where is the sleeping sickness and many people are affected?
According to estimates by the World Health Organization (WHO), about 60 million people living in underdeveloped areas of Africa, are exposed to get this disease. According to the decade of 80, each year an estimated 20,000 new cases of human African trypanosomiasis (although it is thought that the actual numbers should be higher) and WHO estimated 300 to 500,000 the number of people affected by the disease . There are two forms of sleeping sickness:West African Trypanosomiasis
It occurs in central and western equatorial Africa and tropical. It is caused by Trypanosoma brucei gambiense, a parasite reservoir is almost exclusive to humans, not normally found in other animal species. The fly which transmits live primarily in forests, woodlands and river banks. The risk of transmission to humans increases during the dry season, which increases the concentration of people and flies around the wells or locations where there is water. Because of this, the disease is a serious problem for rural populations in the area, but rarely affects tourists.
East African Trypanosomiasis
Exists mainly in forested areas and plains of East Africa (Tanzania, Mozambique, Zimbabwe etc.). It is caused by Trypanosoma brucei rhodesiense, the main reservoir is not the man, but several species of wild animals, mainly antelope, which are tolerant to the parasite, and can have it without causing them disturbance. Many species of domestic animals (especially cattle), he causes serious illness, as well as humans. People usually become infected incidentally by the bite of flies that feed mainly on the blood of wild animals.
The eastern form is therefore a natural reservoir in wild animals which makes it very difficult to eradicate.
From the thirties attempts are being made to control sleeping sickness and the number of cases was declining. But in the last 30 years the situation has worsened due to, among other causes, poverty and the cessation of monitoring programs. In areas where the disease was believed eradicated have reappeared. There are also endemic in parts of Angola, Uganda, Sudan and the Democratic Republic of Congo where it is estimated that over 20% of the population is infected.
Other trypanosome species can cause disease in man: the Trypanosoma cruci causes American trypanosomiasis or Chagas disease, transmitted by bedbugs.
credit to: Dr. Juan Álvarez Orejón, Dr. Charlie Easmon