What Are the Most Deadly Diseases in Africa?

African trypanosomiasis, also known as African sleep disease or drowsiness encephalitis, is a zoonotic parasitic disease transmitted by trypanosoma brucei via the bite of the tongue fly (commonly known as tsetse fly), which is raging in sub-Saharan Africa. The prevalence in some endemic areas is as high as 80%.

Basic Information

nickname: African Sleep Disease or Sleepiness Encephalitis
English name: African trypanosomiasis
Visiting department: Neurology
Multiple groups: People in Sub-Saharan Africa
Common causes: Trypanosoma brucei infection

Common symptoms: Swollen skin with red spots in the center, fever, headache, joint pain, limb pain, ataxia, tremor, cramps, lethargy, lethargy, etc.
Contagious: Have
way for spreading: Spread by tongue fly bites

Causes of African Trypanosomiasis

The trypanosomiasis pathogen is Trypanosoma brucei. Among them, trypanosoma brucei causes Gambia trypanosomiasis, and Rhodesia trypanosoma brucei causes rhodesia trypanosomiasis. The source of infection of Gambia trypanosomiasis is mainly patients, because most of them are chronic and have asymptomatic carriers. Some domestic animals such as cattle, pigs and wild animals such as antelope can also be used as storage hosts. The main storage host of Rhodesia trypanosomiasis is domestic animals and wild animals such as African antelope, lion, hunting dog, monkey, etc. The patient can also be the source of infection.

Clinical manifestations of African trypanosomiasis

The basic process after the two types of trypanosomes invade the human body includes: the local primary reaction phase caused by local proliferation of trypanosomes and the hemolymph phase spread in the body, and the meningitis phase that invades the central nervous system.

Initial response period

About one week after the patient was bitten by the tongue fly, the local skin was swollen and a red dot appeared in the center, which was the trypanosoma. Lymphocytes, histiocytes, and a small amount of eosinophils and macrophages infiltrated in the subcutaneous tissue at the "chancre" site. Sometimes trypanosomes are visible. Local skin lesions are self-limiting and will resolve after approximately 3 weeks.

2. Hemolymph phase

After trypanosoma enters the blood and interstitial lymphatic fluid, it can persist in the blood and lymphatic system for a long time, causing extensive lymphadenopathy, in which lymphocytes, plasma cells, and macrophages proliferate. Trypanosoma blood occurs 5 to 12 days after infection disease. As the surface antigens of the worms mutate at intervals, causing the specific antibodies originally produced to lose their effect, causing the number of trypanosomes in the blood to rise and fall alternately. The interval is 2 to 10 days. The peak of helminthemia can last for 2 to 3 days, with symptoms such as fever, headache, joint pain, and limb pain. The fever continued for several days and subsided on its own. After a few days the body temperature can rise again. In this stage, systemic lymphadenopathy may occur, especially in the back of the neck, submandibular, and groin. Posterior cervical lymphadenopathy (Winterbottom's sign) is characteristic of Gambia trypanosomiasis. Other signs include deep hypersensitivity (Kerandel's sign). In addition, myocarditis, epicarditis, and pericardial effusion can also occur. Meningitis, cerebral congestion and edema, neuron degeneration, and glial cell proliferation. The main clinical symptoms are personality changes and an aspirational state. Abnormal reflexes, such as deep hypersensitivity, ataxia, tremors, cramps, lethargy, and lethargy.

The course of the disease caused by the two types of trypanosomes is different. The trypanosomes of the Gambia have a chronic process that can last for months to years. There may be multiple fevers during the course, but the symptoms are mild. Sometimes there are no acute symptoms, but central nervous system abnormalities may occur; Rhodesia trypanosomiasis is an acute process with a course of 3 to 9 months. Patients often show significant weight loss, high fever and failure. Some patients have died before the central nervous system has been invaded.

African trypanosomiasis check

Pathogen inspection

A smear test can be used to take a patient's blood smear for microscopy. When the number of worms in the blood is large, the cone flagellum is mainly slender, and when the number of blood worms is reduced due to the host's immune response, the stubby type is mostly. Lymphatic fluid, cerebrospinal fluid, bone marrow aspiration fluid, lymph node puncture, etc. can also be taken for smear examination.

2. Serological diagnosis method

Methods such as enzyme-linked immunosorbent assay (ELISA), indirect fluorescent antibody test, and indirect hemagglutination test are commonly used.

3. Molecular biology methods

In recent years, the application of PCR and DNA probe technology to trypanosomiasis has higher specificity and sensitivity. In addition, animal vaccination is a useful test.

African Trypanosomiasis Diagnosis

Anyone who comes from an endemic area in Africa who finds trypanosomiasis, "irregular fever", severe fever, severe headache, lethargy, lethargy, lymphadenopathy, and tachycardia all contribute to the diagnosis. The diagnosis depends on the discovery of the pathogen.

African trypanosomiasis differential diagnosis

Trypanosomiasis should be distinguished from other insect bites, cellulitis, or scorch. The lymphatic blood phase should be distinguished from fever diseases such as malaria, typhoid fever, recurrent fever, and viral hemorrhagic fever. The late stage should be distinguished from various types of meningitis or meningoencephalitis in the acute phase of cerebral malaria, viral encephalitis, bacterial meningitis, tuberculous meningitis, neurosyphilis, and cerebrospinal fluid with mononuclear cells increasing. Should be noted that the disease occasionally positive syphilis serum test.

African Trypanosomiasis Treatment

Therapeutic drugs: Suramin is effective in the early stage of the disease. Other drugs include pentamidine and melarsoprol (melathioarsinol). In cases involving the central nervous system, organic arsenic must be used for treatment.

African Trypanosomiasis Prognosis

Those with no abnormal cerebrospinal fluid had a good prognosis after treatment. Those with obvious abnormalities of cerebrospinal fluid have a poor prognosis, and the cure rate is only 30%. Both types of human trypanosomiasis can be fatal without treatment.

African trypanosomiasis prevention

The basis for the control of trypanosomiasis in the Gambia is to screen and treat a large number of asymptomatic infections, especially those with enlarged lymph nodes, while treating patients and strengthening the management of livestock. Personal protection should be strengthened when entering untreated tsetse breeding areas. Including wearing long-sleeved tops and long-leg pants, wearing bright-colored clothes, using mosquito nets during sleep, using insect repellents, etc., can prevent the attack of tsetse flies. Elimination of the tongue fly: change the breeding environment of vector insects, such as removing bush forests and spraying pesticides.