Manyfactorscontributetothepathogenesisofsleepingsickness,among
themtheactivationofkallikrein,kinin,complement,andthecoagulationsys-
tembycirculatingimmunecomplexes(resultinginincreasedvascularper-
meability,edema,hemostasis,tissuehypoxia,tissuedamage,disseminated
intravasalcoagulation),inadditionanemia,depositionofimmunecomplexes
inthekidneysandotherorgans,immunosuppression,endocrinaldistur-
bances,andCNSdamage.ThetrypanosomescauseCD8+Tcellsandmacro-
phagestoproduceIFNcandTNF.IFNcstimulatestrypanosomestomultiply.
TNFcontributestoimmunosuppressionandmayinitiatetissuedamage.
Diagnosis.Importantdiagnostictoolsincludedirectdetectionofthetrypa-
nosomesintheblood,lymphnodeaspirateand,incerebralforms,inthece-
rebrospinalfluid(Fig.9. 5 ).Trypanosomescanbedetectedinnativeblood
preparations, inGiemsa-stained thin smears or in thickblood films
(p.622).Sincelow-levelparasitemiasareoftenpresent,concentrationmeth-
odsmayberequired,e.g.,microhematocritcentrifugation,anionexchange
chromatography,ortheQBCtechnique(p. 53 1).Othermethodsarecultiva-
tionandmouseinoculationtests(suitableforT.rhodesiense).Analysisof
lymphnodeaspiratehasahighdiagnosticvalueininfectionswithT.gam-
biense.ToconfirmorexcludeCNSinfectionsobtainacerebrospinalfluidsam-
ple,centrifugeit,andexaminethesedimentfortrypanosomes.Antibodiesin
thebloodstreamcanbedetectedusingvarioustechniques(p.625).Thecard
agglutinationtrypanosomosistest(CATT)hasprovedvaluableinepidemio-
logicalsurveys.Indicatorsofastage 2 infectionincludepresenceoftrypano-
somesand/orraisedleukocytenumbersandelevatedconcentrationsofpro-
teinandIgMincerebrospinalfluid.
Therapy.Medicaltreatmentofsleepingsicknessishighlyproblematical,
sinceonlyasmallnumberofeffectivedrugsareavailable,serioussideeffects
arefairlyfrequentanddrug-resistanttrypanosomesaretobeexpected.In
stage 1 ,T.gambienseinfectionsaremainlytreatedwithpentamidine,whereas
T.rhodesienseinfectionsaretreatedwithsuramin.Thesedrugsarenoteffec-
tiveinthesecondstage(cerebrospinalfluid-positivecases),sothatthear-
seniccompoundmelarsoprol,arelativelytoxicsubstance,mustbeusedin
thesecases.Theworstsideeffectofthissubstanceisapotentiallylethalen-
cephalopathyobservedin 1 – 10 %ofpatientstreatedwithmelarsoprol.Eflor-
nithineisusedfortreatingthelatestageoftheT.gamibienseinfection.Treat-
mentofsleepingsicknessvictimsshouldbeentrustedtospecialistsifpos-
sible.
Preventionandcontrol.Useindividualprophylacticmeasurestoprotect
againstthediurnallyactive(!)Glossinaflies.Itisveryimportantthattourists
wearclothingthatcoverstheskinasmuchaspossibleandtreatuncovered
skinwithrepellents(seeMalaria,p.535).Theyshouldalsoinspecttheinte-490 9 Protozoa9
Kayser, Medical Microbiology © 2005 Thieme