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AAAAA everyone be afraid of Tsetse flies (Tsetse - transl. from Ukr.), there is a 0,138(3) probability that these flies will enter your city, so you must be warned; fill your head with useless information about these flies and then maybe they won't bite you.
Human African trypanosomiasis, also known as sleeping sickness, is a parasitic disease transmitted through vectors of the pathogen. These parasites are protozoa belonging to the genus Trypanosoma. They are transmitted to humans through the bites of tsetse flies (genus Glossina), which become infected from humans or animals that carry these pathogenic human parasites.
Tsetse flies are widespread in Africa. Only certain species transmit the disease. Different species have different habitats. They are mainly found in vegetation near rivers and lakes, in gallery forests, and in vast areas of wooded savanna.
Sleeping sickness occurs only in sub-Saharan Africa, in areas where tsetse flies that transmit this disease are present. For reasons that remain unexplained, there are many areas where tsetse flies are widespread, yet sleeping sickness is absent.
Rural populations living in transmission areas who engage in agriculture, fishing, animal husbandry, or hunting are most susceptible to the bites of tsetse flies and, therefore, to this disease.
As a rule, sleeping sickness occurs in remote rural areas where healthcare systems are weak or non-existent. This disease spreads among the poor. Important factors leading to increased transmission are population movements, war, and poverty.
The disease develops in areas ranging in size from a single village to an entire region. Within a single area, the intensity of the disease may vary between villages.
Depending on the parasite, human African trypanosomiasis has two forms:
Trypanosoma brucei gambiense (T.b.g.) is found in West and Central Africa. This form accounts for more than 90% of reported cases of sleeping sickness and causes a chronic infection. A person can be infected for months or even years without serious signs or symptoms of the disease. When symptoms appear, the patient is often in an advanced stage of the disease where the central nervous system is affected.
Trypanosoma brucei rhodesiense (T.b.r.) is found in East and South Africa. This form accounts for less than 10% of reported cases and causes an acute infection. The first signs and symptoms are observed after several months or weeks. The disease progresses rapidly and affects the central nervous system.
Another form of trypanosomiasis occurs in South America. It is known as American trypanosomiasis or Chagas disease. The organism causing this disease differs from the species that causes the African form of the disease.
Animal Trypanosomiasis
Other species and subspecies of parasites of the genus Tripanosoma are pathogenic to animals and cause animal trypanosomiasis among many species of wild and domestic animals (this disease in cattle is called "nagana" (Nagana), which means "to be depressed" in Zulu). Animals can be carriers of pathogenic human parasites, especially T.b. rhodesiense; thus, domestic and wild animals are an important reservoir for the parasites. Animals can also be infected with T.b. gambiense, although the epidemiological role of this reservoir has not yet been precisely established.
The infection of domestic animals with this disease, and particularly cattle, is a serious obstacle to the economic development of affected rural areas. Major epidemics of sleeping sickness in the past took many human lives, and as a result, fertile lands were abandoned.
Major Epidemics
Over the last century, several epidemics have occurred in Africa: one between 1896 and 1906, mainly in Uganda and the Congo River basin; one in 1920 in a number of African countries; and the most recent began in 1970. The 1920 epidemic was halted thanks to mobile screening teams organizing the testing of millions of people at risk. By the mid-1960s, this disease had almost disappeared. Following this success, epidemiological surveillance was relaxed, and over the last 30 years, the disease has reappeared in several areas. Recent efforts by the WHO, national control programs, as well as non-governmental organizations, have stopped and begun to reverse the trend of increasing new cases.
Geographical Distribution of the Disease
Sleeping sickness threatens millions of people in 36 sub-Saharan African countries. However, only a small proportion of them are under surveillance with regular examinations, have access to any medical center capable of providing diagnostic tools, or are protected by vector control measures.
In 1986, a group of experts convened by the WHO made an estimate that about 70 million people live in areas where transmission of this disease may occur.
In 1998, nearly 40,000 cases were registered; however, it was considered that this number does not reflect the true situation, and according to estimates, another 300,000 to 500,000 cases remain undiagnosed and therefore untreated.
During recent epidemic episodes in several villages in the Democratic Republic of the Congo (DRC), Angola, and South Sudan, the prevalence of the disease reached 50%. In these communities, sleeping sickness is regarded as the first or second most significant cause of mortality, surpassing even HIV/AIDS.
By 2005, surveillance was strengthened, and the number of new cases diagnosed across the continent decreased significantly; between 1998 and 2004, rates for both forms of this disease combined dropped from 37,991 to 17,616 cases. Currently, the number of cases is estimated at 50,000 to 70,000.
Progress in establishing control over the disease
In 2000, the WHO established a public-private partnership with "Aventis Pharma" (now "Sanofi-Aventis"), which allowed for the creation of a surveillance team that supports endemic countries in their fight against the disease and ensures free supplies of drugs for treating patients.
In 2006, the success achieved in reducing the number of sleeping sickness cases prompted several private entities to support initial efforts toward eliminating this disease as a public health problem.
CURRENT SITUATION IN ENDEMIC COUNTRIES
The prevalence of this disease varies between countries, as well as in different parts of a single country. In 2005, serious outbreaks were observed in Angola, the Democratic Republic of the Congo, and Sudan. In the Central African Republic, Chad, Congo, Côte d'Ivoire, Guinea, Malawi, Uganda, and the United Republic of Tanzania, sleeping sickness remains a serious public health problem. Countries such as Burkina Faso, Cameroon, Equatorial Guinea, Gabon, Kenya, Mozambique, Nigeria, Rwanda, Zambia, and Zimbabwe report fewer than 50 new cases per year. In countries such as Benin, Botswana, Burundi, Ethiopia, Gambia, Ghana, Guinea-Bissau, Liberia, Mali, Namibia, Niger, Senegal, Sierra Leone, Swaziland, and Togo, transmission has apparently ceased, and no reports of new cases have been received for several decades. Nevertheless, due to the lack of surveillance and diagnostic specialists, assessing the current situation in a number of endemic countries is difficult.
Infection and Symptoms
The disease is transmitted as a result of the bite of an infected tsetse fly. Initially, trypanosomes multiply in subcutaneous tissues, blood, and lymph. Over time, the parasites cross the blood-brain barrier and infect the central nervous system. In the case of T.b. gambiense, this process can last for years.
Mother-to-child transmission: trypanosomes can cross the placental barrier and infect the fetus.
Mechanical transmission is possible. However, assessing the epidemiological consequences of transmission via other blood-sucking insects is difficult.
Accidental infections have occurred in laboratories as a result of pricks with contaminated needles.
In the first stage of the disease, known as hemolymphatic, there are bouts of fever, headache, joint pain, and itching. The second stage, known as neurological, occurs after the parasite crosses the blood-brain barrier and enters the central nervous system. Generally, signs and symptoms of the disease appear at this stage: confusion, sensory disturbances, and impaired coordination. An important element of the second stage is the disruption of the sleep-wake cycle, from which the disease derived its name. In the absence of treatment, sleeping sickness leads to a fatal outcome.
Disease Management
Disease management is carried out in three stages:
Screening consists of the initial identification of people who may be infected. This involves serological tests and/or checking for clinical signs—typically swollen cervical glands.
As a result of diagnosis, the presence or absence of the parasite is established.
Staging of the disease shows how far the disease has progressed. It consists of analyzing cerebrospinal fluid obtained via lumbar puncture and serves to determine the course of treatment.
A diagnosis should be made as early as possible and before the neurological stage occurs to avoid complex, difficult, and risky treatment procedures.
The prolonged asymptomatic first stage of sleeping sickness caused by T.b. gambiense is one of the factors requiring comprehensive active screening of populations at risk in order to identify patients at an early stage and reduce disease transmission.
Treatment
The type of treatment depends on the stage of the disease, as drugs used in the first stage are less toxic, easier to administer, and more effective. The earlier the disease is detected, the better the prospects for treatment. Success of second-stage treatment depends on a drug that can cross the blood-brain barrier to act on the parasites. Such drugs are more difficult to apply. Four drugs are registered for the treatment of sleeping sickness, which are provided to endemic countries free of charge through the WHO's private partnership with "Sanofi-Aventis" (pentamidine, melarsoprol, and eflornithine) and "Bayer AG" (suramin).
First-stage Treatment
Pentamidine: discovered in 1941, used to treat the first stage of T.b. gambiense sleeping sickness. Despite some adverse effects, it is well tolerated by patients.
Suramin: discovered in 1921, used to treat the first stage of T.b. rhodesiense sleeping sickness. It causes certain adverse effects in the urinary tract and allergic reactions.
Second-stage Treatment
Melarsoprol: discovered in 1949, used for both forms of infection. It is an arsenic derivative and has numerous undesirable side effects. The most prominent is reactive encephalopathy (encephalopathic syndrome), which can be fatal (from 3% to 10%). An increase in resistance to this drug is observed in several foci, especially in Central Africa.
Eflornithine: this molecule was registered in 1990. It is effective only against T.b. gambiense sleeping sickness. It is an alternative to treatment with melarsoprol. Its administration regimen is difficult and requires strict adherence.
Role of the World Health Organization
The reappearance of sleeping sickness in the 1970s prompted the WHO to strengthen its program for combating human African trypanosomiasis. The goal is to coordinate activities in endemic countries and mobilize a wide range of partners.
As part of the program, the WHO provides support and technical assistance to national programs fighting sleeping sickness. A network has been created including donor countries, private foundations, non-governmental organizations, regional institutions, research centers, and universities to participate in surveillance and disease control and in implementing research projects for the development of new drugs and diagnostic tools.
The goals of the WHO program are:
strengthening and coordinating control measures and ensuring further activity on the ground;
strengthening existing surveillance systems;
support through a network for monitoring treatment and drug resistance;
developing an information database and providing personnel training measures.
developing inter-agency cooperation with the Food and Agriculture Organization of the United Nations (FAO) and the International Atomic Energy Agency (IAEA). This institution deals with vector control by sterilizing males using radiation. Additionally, there is a joint Program for the Control of African Trypanosomiasis (PCAT), including the WHO (human health), FAO (animal health), and IAEA (vector control).
So that's what I was getting at; as Socrates said, "Oh how many things in the world are unnecessary to me!" (Remember this phrase more often when you enter a supermarket or Ikea, you will save a lot of money).
All you need is to know simple hygiene rules and not overcomplicate your life.
Human African trypanosomiasis, also known as sleeping sickness, is a parasitic disease transmitted through vectors of the pathogen. These parasites are protozoa belonging to the genus Trypanosoma. They are transmitted to humans through the bites of tsetse flies (genus Glossina), which become infected from humans or animals that carry these pathogenic human parasites.
Tsetse flies are widespread in Africa. Only certain species transmit the disease. Different species have different habitats. They are mainly found in vegetation near rivers and lakes, in gallery forests, and in vast areas of wooded savanna.
Sleeping sickness occurs only in sub-Saharan Africa, in areas where tsetse flies that transmit this disease are present. For reasons that remain unexplained, there are many areas where tsetse flies are widespread, yet sleeping sickness is absent.
Rural populations living in transmission areas who engage in agriculture, fishing, animal husbandry, or hunting are most susceptible to the bites of tsetse flies and, therefore, to this disease.
As a rule, sleeping sickness occurs in remote rural areas where healthcare systems are weak or non-existent. This disease spreads among the poor. Important factors leading to increased transmission are population movements, war, and poverty.
The disease develops in areas ranging in size from a single village to an entire region. Within a single area, the intensity of the disease may vary between villages.
Depending on the parasite, human African trypanosomiasis has two forms:
Trypanosoma brucei gambiense (T.b.g.) is found in West and Central Africa. This form accounts for more than 90% of reported cases of sleeping sickness and causes a chronic infection. A person can be infected for months or even years without serious signs or symptoms of the disease. When symptoms appear, the patient is often in an advanced stage of the disease where the central nervous system is affected.
Trypanosoma brucei rhodesiense (T.b.r.) is found in East and South Africa. This form accounts for less than 10% of reported cases and causes an acute infection. The first signs and symptoms are observed after several months or weeks. The disease progresses rapidly and affects the central nervous system.
Another form of trypanosomiasis occurs in South America. It is known as American trypanosomiasis or Chagas disease. The organism causing this disease differs from the species that causes the African form of the disease.
Animal Trypanosomiasis
Other species and subspecies of parasites of the genus Tripanosoma are pathogenic to animals and cause animal trypanosomiasis among many species of wild and domestic animals (this disease in cattle is called "nagana" (Nagana), which means "to be depressed" in Zulu). Animals can be carriers of pathogenic human parasites, especially T.b. rhodesiense; thus, domestic and wild animals are an important reservoir for the parasites. Animals can also be infected with T.b. gambiense, although the epidemiological role of this reservoir has not yet been precisely established.
The infection of domestic animals with this disease, and particularly cattle, is a serious obstacle to the economic development of affected rural areas. Major epidemics of sleeping sickness in the past took many human lives, and as a result, fertile lands were abandoned.
Major Epidemics
Over the last century, several epidemics have occurred in Africa: one between 1896 and 1906, mainly in Uganda and the Congo River basin; one in 1920 in a number of African countries; and the most recent began in 1970. The 1920 epidemic was halted thanks to mobile screening teams organizing the testing of millions of people at risk. By the mid-1960s, this disease had almost disappeared. Following this success, epidemiological surveillance was relaxed, and over the last 30 years, the disease has reappeared in several areas. Recent efforts by the WHO, national control programs, as well as non-governmental organizations, have stopped and begun to reverse the trend of increasing new cases.
Geographical Distribution of the Disease
Sleeping sickness threatens millions of people in 36 sub-Saharan African countries. However, only a small proportion of them are under surveillance with regular examinations, have access to any medical center capable of providing diagnostic tools, or are protected by vector control measures.
In 1986, a group of experts convened by the WHO made an estimate that about 70 million people live in areas where transmission of this disease may occur.
In 1998, nearly 40,000 cases were registered; however, it was considered that this number does not reflect the true situation, and according to estimates, another 300,000 to 500,000 cases remain undiagnosed and therefore untreated.
During recent epidemic episodes in several villages in the Democratic Republic of the Congo (DRC), Angola, and South Sudan, the prevalence of the disease reached 50%. In these communities, sleeping sickness is regarded as the first or second most significant cause of mortality, surpassing even HIV/AIDS.
By 2005, surveillance was strengthened, and the number of new cases diagnosed across the continent decreased significantly; between 1998 and 2004, rates for both forms of this disease combined dropped from 37,991 to 17,616 cases. Currently, the number of cases is estimated at 50,000 to 70,000.
Progress in establishing control over the disease
In 2000, the WHO established a public-private partnership with "Aventis Pharma" (now "Sanofi-Aventis"), which allowed for the creation of a surveillance team that supports endemic countries in their fight against the disease and ensures free supplies of drugs for treating patients.
In 2006, the success achieved in reducing the number of sleeping sickness cases prompted several private entities to support initial efforts toward eliminating this disease as a public health problem.
CURRENT SITUATION IN ENDEMIC COUNTRIES
The prevalence of this disease varies between countries, as well as in different parts of a single country. In 2005, serious outbreaks were observed in Angola, the Democratic Republic of the Congo, and Sudan. In the Central African Republic, Chad, Congo, Côte d'Ivoire, Guinea, Malawi, Uganda, and the United Republic of Tanzania, sleeping sickness remains a serious public health problem. Countries such as Burkina Faso, Cameroon, Equatorial Guinea, Gabon, Kenya, Mozambique, Nigeria, Rwanda, Zambia, and Zimbabwe report fewer than 50 new cases per year. In countries such as Benin, Botswana, Burundi, Ethiopia, Gambia, Ghana, Guinea-Bissau, Liberia, Mali, Namibia, Niger, Senegal, Sierra Leone, Swaziland, and Togo, transmission has apparently ceased, and no reports of new cases have been received for several decades. Nevertheless, due to the lack of surveillance and diagnostic specialists, assessing the current situation in a number of endemic countries is difficult.
Infection and Symptoms
The disease is transmitted as a result of the bite of an infected tsetse fly. Initially, trypanosomes multiply in subcutaneous tissues, blood, and lymph. Over time, the parasites cross the blood-brain barrier and infect the central nervous system. In the case of T.b. gambiense, this process can last for years.
Mother-to-child transmission: trypanosomes can cross the placental barrier and infect the fetus.
Mechanical transmission is possible. However, assessing the epidemiological consequences of transmission via other blood-sucking insects is difficult.
Accidental infections have occurred in laboratories as a result of pricks with contaminated needles.
In the first stage of the disease, known as hemolymphatic, there are bouts of fever, headache, joint pain, and itching. The second stage, known as neurological, occurs after the parasite crosses the blood-brain barrier and enters the central nervous system. Generally, signs and symptoms of the disease appear at this stage: confusion, sensory disturbances, and impaired coordination. An important element of the second stage is the disruption of the sleep-wake cycle, from which the disease derived its name. In the absence of treatment, sleeping sickness leads to a fatal outcome.
Disease Management
Disease management is carried out in three stages:
Screening consists of the initial identification of people who may be infected. This involves serological tests and/or checking for clinical signs—typically swollen cervical glands.
As a result of diagnosis, the presence or absence of the parasite is established.
Staging of the disease shows how far the disease has progressed. It consists of analyzing cerebrospinal fluid obtained via lumbar puncture and serves to determine the course of treatment.
A diagnosis should be made as early as possible and before the neurological stage occurs to avoid complex, difficult, and risky treatment procedures.
The prolonged asymptomatic first stage of sleeping sickness caused by T.b. gambiense is one of the factors requiring comprehensive active screening of populations at risk in order to identify patients at an early stage and reduce disease transmission.
Treatment
The type of treatment depends on the stage of the disease, as drugs used in the first stage are less toxic, easier to administer, and more effective. The earlier the disease is detected, the better the prospects for treatment. Success of second-stage treatment depends on a drug that can cross the blood-brain barrier to act on the parasites. Such drugs are more difficult to apply. Four drugs are registered for the treatment of sleeping sickness, which are provided to endemic countries free of charge through the WHO's private partnership with "Sanofi-Aventis" (pentamidine, melarsoprol, and eflornithine) and "Bayer AG" (suramin).
First-stage Treatment
Pentamidine: discovered in 1941, used to treat the first stage of T.b. gambiense sleeping sickness. Despite some adverse effects, it is well tolerated by patients.
Suramin: discovered in 1921, used to treat the first stage of T.b. rhodesiense sleeping sickness. It causes certain adverse effects in the urinary tract and allergic reactions.
Second-stage Treatment
Melarsoprol: discovered in 1949, used for both forms of infection. It is an arsenic derivative and has numerous undesirable side effects. The most prominent is reactive encephalopathy (encephalopathic syndrome), which can be fatal (from 3% to 10%). An increase in resistance to this drug is observed in several foci, especially in Central Africa.
Eflornithine: this molecule was registered in 1990. It is effective only against T.b. gambiense sleeping sickness. It is an alternative to treatment with melarsoprol. Its administration regimen is difficult and requires strict adherence.
Role of the World Health Organization
The reappearance of sleeping sickness in the 1970s prompted the WHO to strengthen its program for combating human African trypanosomiasis. The goal is to coordinate activities in endemic countries and mobilize a wide range of partners.
As part of the program, the WHO provides support and technical assistance to national programs fighting sleeping sickness. A network has been created including donor countries, private foundations, non-governmental organizations, regional institutions, research centers, and universities to participate in surveillance and disease control and in implementing research projects for the development of new drugs and diagnostic tools.
The goals of the WHO program are:
strengthening and coordinating control measures and ensuring further activity on the ground;
strengthening existing surveillance systems;
support through a network for monitoring treatment and drug resistance;
developing an information database and providing personnel training measures.
developing inter-agency cooperation with the Food and Agriculture Organization of the United Nations (FAO) and the International Atomic Energy Agency (IAEA). This institution deals with vector control by sterilizing males using radiation. Additionally, there is a joint Program for the Control of African Trypanosomiasis (PCAT), including the WHO (human health), FAO (animal health), and IAEA (vector control).
So that's what I was getting at; as Socrates said, "Oh how many things in the world are unnecessary to me!" (Remember this phrase more often when you enter a supermarket or Ikea, you will save a lot of money).
All you need is to know simple hygiene rules and not overcomplicate your life.
