Sleeping sickness (Human African Trypanosomiasis) By Rachel Kaplan.
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Transcript of Sleeping sickness (Human African Trypanosomiasis) By Rachel Kaplan.
Sleeping sickness
(Human African Trypanosomiasis)
By Rachel Kaplan
Trypanosomiasis affects thousands in central Africa
• Only found in 36 sub-saharan African countries where tsetse fly is found
• ~50 million people in at-risk areas
• In 1993 there were 55,000 deaths
Most African nations gained independence from colonial powers in the 1960’s.
After independence, the incidence of sleeping sickness rose dramatically.
It is now being brought back under control.
1998 2005 20090
50,000
100,000
150,000
200,000
250,000
300,000
350,000
Reported CasesEstimated Actual Cases
The trypanosome is the causative agent.
It’s transmitted by the tsetse fly
How Transmission Works
Reservoir
How Transmission Works
There are 4 forms of trypanosomiasis.
• Chagas disease- American Trypanosomiasis, found in Latin America
• Nagana- “to be depressed,” animal form• Trypanosoma brucei rhodesiense- East Africa,
acute• Trypanosoma brucei gambiense- West Africa,
chronic, 95% of cases
Trypanosomes are multiplying in subcutaneous tissues (inner layer of 3 layers of skin), blood, and lymph
Symptoms: fever, headaches, joint pains, itching
Stage 1
Stage 2- Trypanosomes cross the blood/brain barrier
Symptoms: behavior/personality changes, confusion, disturbance of sleep cycle
T. Rhodesiense has similar symptoms to T. Gambiense, but it is faster.
Stage T. Rhodesiense (acute)
T. Gambiense (chronic)
Stage 1 Weeks to months after infection
Months to years after infection
Stage 2 Several months after infection
Up to several years after infection
You can mount an immune response, but the trypanosome fights back.
• VSG- variant surface glycoprotein• Chromosome repair moves new gene to
surface• New surface structure evades immune
response
Time
Para
site
s in
bod
y
Because symptoms can remain hidden for so long, testing is vital.
There are effective treatments available.
Happily, the main 4 drugs for Human African Trypanosomiasis are supplied to endemic
countries free of charge.
But…
TreatmentDrug What it can
treatHow it is
administeredSide effects
Pentamidine 1st stage t.b. gambiense
7-10 intramuscular
injections a day or alternate
days
Minimal but significant
Suramin 1st stage both forms
5 intravenous injections every
5-7 days
Urinary tract problems,
allergic reactions
Eflornithine 1st and 2nd stage t.b. gambiense
Intravenous injection every 6 hours for 14
days
Some, but less toxic than
melarsoprol
Melarsoprol 1st and 2nd stage both forms
3-4 series of intravenous injections
separated by 1 weeks
Many undesirable side effects,
including death in 1-5% of patients
There are massive impediments to diagnosis and treatment.
Vector control has been found to be effective.
We’re making dramatic progress.
1998 2005 20090
50,000
100,000
150,000
200,000
250,000
300,000
350,000
Reported CasesEstimated Actual Cases
Photos• http://www.doctorswithoutborders.org/news/issue.cfm?id=2401• http://findmeacure.com/2010/04/09/sleeping-sickness-african-trypan
osomiasis/• http://www.wrongdiagnosis.com/phil/html/african-sleeping-sickness/6
13.html• http://www.iaea.org/NewsCenter/Features/Tsetse/index.shtml• http://blog.africaimports.com/wordpress/?p=2246• http://dna.kdna.ucla.edu/parasite_course-old/african%20tryps%20ne
w_files/subchapters/Epidemiology.htm• http://www.bmj.com/content/325/7357/203.1.full• http://thomashawk.com/2004/08/thomas-hawks-digital-photoblog-au
gust.html• http://www.petsfoto.com/top-10-deadliest-insects/• http://www.worldproutassembly.org/archives/2007/09/livestock_bree
d.html• http://www.parasitemuseum.com/trypanosome/• http://www.yoursolarlink.com/blog/solar-pebbles-for-rural-africa/• http://exploringafrica.matrix.msu.edu/students/curriculum/m14/pics4.
php• http://etc.usf.edu/clipart/18900/18909/net_18909.htm• http://www.earlham.edu/~martilu/trypanosomiasispathology.htm
Sources• http://www.who.int/mediacentre/factsheets/fs259/en
/• http://www.cdc.gov/parasites/sleepingsickness/• Documentary: Survival- The Deadliest Disease
http://www.rockhopper.tv/programmes/150/• http://bmb.oxfordjournals.org/content/41/2/169.full.p
df+html• http://www.humpath.com/african-trypanosomiasis• http://apps.who.int/tdr/svc/diseases/african-trypanos
omiasis• http://www.sciencedirect.com/science?_ob=ArticleUR
L&_udi=B6T1R-47GJC1J-2&_user=130907&_coverDate=09%2F30%2F1993&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_acct=C000004198&_version=1&_urlVersion=0&_userid=130907&md5=bcd6671a39e122bb349b4215d9bb95f2&searchtype=a
• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2120053/pdf/jc12551147.pdf
• http://www.cdc.gov/parasites/sleepingsickness/health_professionals/index.html
• Man against Tsetse: Struggle for Africa by John J. McKelvey