TrypanosomiasisTrypanosomiasis

Ziad Elnasser, MD, Ph.DZiad Elnasser, MD, Ph.D

ParasitologyParasitology

Trypanosoma brucei Trypanosoma brucei with 3 subspecies:with 3 subspecies:gambiense, rhodesiense and brucei gambiense, rhodesiense and brucei identified identified

by their biology, zymodemes and DNA types.by their biology, zymodemes and DNA types.Life cycle: Glossina fly (tse tse), Life cycle: Glossina fly (tse tse),

epimastigote form, trypomastigote form, epimastigote form, trypomastigote form, saliva, VSG development, blood, division, saliva, VSG development, blood, division, morphology change, antigenic variation, morphology change, antigenic variation, glossina fly.glossina fly.

African trypanosomiasis (Sleeping African trypanosomiasis (Sleeping sickness)sickness)

Lethal meningoencephalitis.Lethal meningoencephalitis.West african or east african types, Nagana West african or east african types, Nagana

in cattle.in cattle.Epidemiology: Africa 10,000 – 20,000/y.Epidemiology: Africa 10,000 – 20,000/y.Humans are reservoirs in gambian while Humans are reservoirs in gambian while

the antelop in Rhodesian.the antelop in Rhodesian.

pathogenesispathogenesis

Skin chancre.Skin chancre.Blood and LNs, IgM and C, antigenic Blood and LNs, IgM and C, antigenic

variation.variation.CNS, and heart small vessles involvement CNS, and heart small vessles involvement

Hg, demyelinating panencephalitis.Hg, demyelinating panencephalitis.Poly clonal B cell activation→IgM, Poly clonal B cell activation→IgM,

heterophile Abs, anti DNA, and RF, cell heterophile Abs, anti DNA, and RF, cell destruction, immune complexes, anemia destruction, immune complexes, anemia and vasculitis.and vasculitis.

Clinical AspectsClinical Aspects

Chancre.Chancre.Fever, tender LNs, rash, headache, and Fever, tender LNs, rash, headache, and

impaired mentation.impaired mentation.Heart failure, convulsions, coma and death Heart failure, convulsions, coma and death

may follow.may follow.Attention waves, tremors, sphinctor control Attention waves, tremors, sphinctor control

is lost, seizures, transient bouts of is lost, seizures, transient bouts of paralysis, and final coma.paralysis, and final coma.

DiagnosisDiagnosis

Lymph nodes aspirate, Blood, CSF→ look Lymph nodes aspirate, Blood, CSF→ look for trypomastigotes, if not centrifuge and for trypomastigotes, if not centrifuge and examine buffy coat.examine buffy coat.

Animal inoculation.Animal inoculation.Ab detection IgM type, simple card Ab detection IgM type, simple card

agglutination.agglutination.DNA probes.DNA probes.

TreatmentTreatment

LP must be done first to use agents LP must be done first to use agents crosses the blood – brain barrier.crosses the blood – brain barrier.

Melarsoprol B is the best.Melarsoprol B is the best.Eflornithin (ornithine dexarboxylase Eflornithin (ornithine dexarboxylase

inhibitor) alone or with Suramine.inhibitor) alone or with Suramine.Less toxic than Mel B, varialbly effective Less toxic than Mel B, varialbly effective

for T. rhodesiense.for T. rhodesiense.Suramine, Pentamidine, or eflornithine can Suramine, Pentamidine, or eflornithine can

be used if the CNS is not involoved.be used if the CNS is not involoved.

PreventionPrevention

Tse tse fly control measures.Tse tse fly control measures. Insecticides.Insecticides.Deforstation.Deforstation.Sterile males.Sterile males.

Eradication of reservoirs.Eradication of reservoirs.Vaccine difficulties.Vaccine difficulties.Personal protection from flies.Personal protection from flies.

American TrypanosomiasisAmerican Trypanosomiasis

Trypanosoma cruzi and reduvid bug.Trypanosoma cruzi and reduvid bug.No extracellular multiplication (amastigote)No extracellular multiplication (amastigote)Trypomastigote → amastigote → Trypomastigote → amastigote →

trypomastigote → epimastigote in bug.trypomastigote → epimastigote in bug.Many serotypes.Many serotypes.C or U shape, large kinetoplast, narrow C or U shape, large kinetoplast, narrow

undulating membrane.undulating membrane.

Chagas diseaseChagas disease

Leading cause of heart disease in s. Leading cause of heart disease in s. America.America.

Reduvid bug bites at night.Reduvid bug bites at night.Kissing bug or assassin bug.Kissing bug or assassin bug.Rats, cats, dogs, opossums, and Rats, cats, dogs, opossums, and

armadillos act as reservoirs.armadillos act as reservoirs.Blood transfusion and transplantation.Blood transfusion and transplantation.

PathogenesisPathogenesis

Local chancre or Chagoma.Local chancre or Chagoma. Febrile illness one to 3 months.Febrile illness one to 3 months. Any nucleated cell in the body can be infected, Any nucleated cell in the body can be infected,

heart, CNS, skeletal muscles.heart, CNS, skeletal muscles. Penetrin on trypomastigote binds to fibronectin Penetrin on trypomastigote binds to fibronectin

transforms to amastigote, pseudocyst transforms to amastigote, pseudocyst development.development.

Humoral and CMI destroys the organism.Humoral and CMI destroys the organism. Parasite antigen binds to other tissues resulting Parasite antigen binds to other tissues resulting

more injury, heart damage.more injury, heart damage.

Clinical AspectsClinical Aspects

Nodular erythematous chagoma.Nodular erythematous chagoma.Romana’s sign if entry is through the eye.Romana’s sign if entry is through the eye.Fever, LNs ↑, hepatospleenomegally.Fever, LNs ↑, hepatospleenomegally.Meningeal irritation, tachycardia, ECG Meningeal irritation, tachycardia, ECG

changes.changes.Myocardium and the induction system.Myocardium and the induction system.Mega colon and megaeosophagus.Mega colon and megaeosophagus.

DiagnosisDiagnosis

Trypomastigote in the peripheral blood.Trypomastigote in the peripheral blood.Xenodiagnosis.Xenodiagnosis.Culture or animal inoculation.Culture or animal inoculation.Chronic disease difficult to diagnose.Chronic disease difficult to diagnose. Immunodiagnosis.Immunodiagnosis.PCR .PCR .

Treatment and preventionTreatment and prevention

Nitrofuramox.Nitrofuramox.Benznidazole.Benznidazole.Allopurinol.Allopurinol. Insecticides, fumagatives.Insecticides, fumagatives.Testing blood donors.Testing blood donors.No vaccines.No vaccines.

Filarial WormsFilarial Worms

Wuchereria bancroftiWuchereria bancroftiBrugia malayi.Brugia malayi.Loa loaLoa loaOnchocerca volvolus.Onchocerca volvolus.