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

sites

in b

ody

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-trypanos

omiasis/• http://www.wrongdiagnosis.com/phil/html/african-sleeping-sickness/61

3.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%20new_

files/subchapters/Epidemiology.htm• http://www.bmj.com/content/325/7357/203.1.full• http://thomashawk.com/2004/08/thomas-hawks-digital-photoblog-augu

st.html• http://www.petsfoto.com/top-10-deadliest-insects/• http://www.worldproutassembly.org/archives/2007/09/livestock_breed.

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.p

hp• 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.pd

f+html• http://www.humpath.com/african-trypanosomiasis• http://apps.who.int/tdr/svc/diseases/african-trypanoso

miasis• http://www.sciencedirect.com/science?_ob=ArticleURL

&_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