Human African trypanosomiasis (HAT) is a zoonosis caused by protozoa (trypanosomes), transmitted to humans by the bite of a tsetse fly (tsetse fly). The transmission is also possible from tainted blood and, in the fetus via the placenta.
Sleeping sickness occurs only in sub-Saharan Africa; there are two forms: HAT Trypanosoma brucei gambiense in West and Central Africa and the THA to Trypanosoma brucei rhodesiense in eastern and southern Africa.
Clinical signs:
Inoculation is sometimes followed by immediate local reaction: inoculation chancre or trypanome, present in approximately 50% of patients infected with T. b. rhodesiense rarely present in patients infected with T. b. gambiense.
Gambiense HAT:
– Incubation lasts from several days to several years.
– The first phase of the disease (haemolymphatic phase) is the parasite dissemination phase in the lymphatic-blood system: intermittent fever, arthralgia, lymphadenopathy (firm nodes, mobile, painless, mainly cervical), frequent hepatosplenomegaly, cutaneous signs (facial edema, pruritus).
– The second phase of the disease (meningoencephalitic phase) is the invasion phase of the central nervous system attenuation or disappearance of signs of the first phase and gradual onset of neurological signs vary depending on the case: sensory disturbances (deep hyperaesthesia ), psychiatric disorders (apathy, agitation), sleep disturbances progressing to an altered sleep-wake rhythm, movement disorders (paralysis, convulsions, tics) and neuroendocrine disorders (amenorrhea, impotence, thyroid deficiency).
– In the absence of treatment: cachexia, drowsiness, coma and death.
THA Rhodesiense:
The initial phase is the same but the evolution is faster and more severe infectious syndrome. She Patients often die of myocarditis in 3 to 6 months sometimes before the onset of signs of brain damage.
In practice, the clinical pictures are not always as clear: there p. ex. acute forms Gambiense and chronic formsRhodesiense.
Laboratory:
– The diagnosis is made in 3 steps for T. b. gambiense (screening, diagnostic confirmation and stage determination) and 2 step for T. b. rhodesiense (diagnostic confirmation and stage determination).
– The CATT (Card Agglutination Test for Trypanosomiasis) is the recommended screening test for Tb gambiense. It detects the presence of specific antibodies in the blood or serum of the patient.
– Confirmation of diagnosis: presence of trypanosomes in lymph nodes (lymph node puncture) or blood concentration after: thick film, capillary tubes concentration (Woo test), QBC, mini ion exchange column (mAECT).
– Phase Diagnosis: trypanosome research (after single or double centrifugation) and white blood cell count in the cerebrospinal fluid (lumbar puncture):
• First phase: no trypanosomes AND ² 5 white blood cells / mm3
• Second phase: presence of trypanosomes OR> 5 white blood cells / mm3
Treatment (except pregnant women):
– Due to the toxicity of trypanocides, the detection of the parasite is essential before initiating treatment. Without parasitological evidence, treatment may be justified in certain circumstances: highly suggestive clinical, life-threatening game, strongly suspects serological cases (CATT 1:16 positive) in a population where the prevalence is high (> 2%).
– There are several regimens. Check national recommendations and local parasitic resistances.
– Treatment should be administered under close medical supervision. Pentamidine can be administered on an outpatient; it is necessary to hospitalize patients treated with suramin or melarsoprol or eflornithine.
– After treatment, the patient is reviewed every 6 months (clinical examination, lumbar puncture, trypanosomes Research) for 24 months to detect relapse.
Haemolymphatic phase:
Gambiense HAT:
pentamidine isetionate deep IM
Children and adults: 4 mg / kg / once daily for 7 to 10 days. Administer glucose (meal, sweet tea) one hour before injection (hypoglycaemia) and keep the patient lying during injection and one hour after (risk of hypotension).
THA Rhodesiense:
suramine slow IV
Children and adults: J1: test dose of 4-5 mg / kg J3-J10-J17-J24-J31: 20 mg / kg up to 1 g / injection
Because of the risk of anaphylaxis, it is recommended to inject a test dose on Day 1. If an anaphylactic reaction during the test dose, suramin should be abandoned definitively.
Meningoencephalitic stage:
The rehabilitation of the general condition (rehydration, treatment for malnutrition, malaria, intestinal worms, bacterial infections) has priority over the implementation of the road trypanocide treatment; it is nevertheless advisable not to postpone it for more than 10 days.
Gambiense HAT:
1st choice: eflornithine administered by IV infusion over 2 hours
Child <12 600 mg / kg / day in 4 divided infusions (every 6 hours) for 14 days
Adult: 400 mg / kg / day in 4 divided infusions (every 6 hours) for 14 days
Nursing care of the catheter must be careful to avoid local or general bacterial infections: thoroughly disinfect, sterile environment at the insertion point, good fixation, catheter change every 48 hours or earlier in case of phlebitis.
2nd choice: melarsoprol slow IV strict
Children and adults: 2.2 mg / kg / once daily for 10 days
The old patterns from March to April sets of 3 to 4 injections (injections / day) with a range of 7 to 10 days between each series are applied in some countries.
PO prednisolone (1 mg / kg / day single dose) is frequently combined throughout the duration of treatment.
The toxicity of melarsoprol is important: reactive encephalopathy (coma or prolonged or repeated seizures) in 5-10% of patients, lethal in 50% of cases; peripheral neuropathy, invasive diarrhea, severe rash, phlebitis, etc.
THA Rhodesiense:
melarsoprol slow IV strict
Children and adults: 3.6 mg / kg / once daily, 3-4 sets of 3-4 injections with a 7 to 10 day interval between each set
Treatment for pregnant women:
All trypanocides are toxic to the mother and child (risk of abortion, malformation). However, because of the vital risk to the mother and the risk of transmission in utero, treatment should be initiated according to the following protocols:
In haemolymphatic phase
pentamidine for gambiense from Q2 and suramine if Rhodesiense.
Phase meningoencephalitic, treatment depends on the general status of the mother:
– If the prognosis is immediately threatened, eflornithine or melarsoprol without waiting for the end of pregnancy.
– If the prognosis is not immediately threatened, pentamidine for gambiense and suramin if Rhodesiense. Treatment with eflornithine or melarsoprol be realized after delivery.
Prevention and control:
– Individual protection against tsetse fly bites: protective clothing, repellents, avoidance of risk areas (eg river banks..).
– Control of the disease mass screening and treatment of patients (T. b gambiense.), Livestock trypanocidal treatment(T. b rhodesiense.), Vector control by trapping or insecticides spraying.
