ANDREA BRADY BIOL 062 African trypanosomiasis (Sleeping Sickness)

ANDREA BRADYBIOL 062

African trypanosomiasis (Sleeping Sickness)

Epidemics have killed hundreds of thousands since 1900.

http://www.microbiologybytes.com/introduction/Trypano.html

http://www.doctorswithoutborders.org/images/news/sleeping/34476.jpg

Tens of thousands continue to die each year

WHO estimated that in 2001, there were 48,000 deaths caused by sleeping sickness.

www.dcp2.org/pubs/DCP/23/Section/3154

Tens of thousands continue to die each year

WHO estimated that in 2001, there were 48,000 deaths caused by sleeping sickness.

Currently, it is estimated the number of deaths per year has increased to 50,000 or as high as 100,000.

http://www.dcp2.org/pubs/DCP/23/Section/3154

As many as 500,000 are currently infected.

http://www.kfwh.org/information.asp

Chart from World Bank, 2006

http://www.dcp2.org/pubs/DCP/23/Table/23.1

Most cases are found in Sub-Saharan Africa.

How can an infectious disease be contained to such a specific region

of the world?

How can an infectious disease be contained to such a specific region of

the world?

Let’s take a closer look at how the disease is spread…

Disease Transfer

The disease is caused by two parasites of the Trypanosoma Genus and brucei Species.

http://en.wikipedia.org/wiki/Sleeping_sickness


http://farm3.static.flickr.com/2110/1760532740_20189a8cdc.jpg

Disease Transfer

The disease is caused by two parasites of the Trypanosoma Genus and brucei Species.

More commonly called Trypanosomes

http://www.who.int/mediacentre/factsheets/fs259/en/


http://farm3.static.flickr.com/2110/1760532740_20189a8cdc.jpg

Trypanosomes are protozoans.


http://jcs.biologists.org/content/vol115/issue12/images/medium/joces11512cvf.gif

Trypanosomes are protozoans. (unicellular eukaryotes) (single flagellum)


http://jcs.biologists.org/content/vol115/issue12/images/medium/joces11512cvf.gif

http://www.modares.ac.ir/elearning/Dalimi/Proto/images/Lectures/fig77_1.JPG

Disease Transfer

The trypanosomes are mainly transferred by the tsetse fly, which is found primarily in Sub-Saharan Africa.


the tsetse fly The tsetse fly

http://library.truman.edu/test/carol/Tsetse_fly.gif

Areas Infested

by the Tsetse Fly

http://www.fao.org/ag/icons/map.gif

Distribution Map for African Sleeping Sickness

http://www.medicalecology.org/diseases/african_trypano/clip_image002.jpg

Areas Infested by tsetse flyAreas Infested by tsetse fly

Distribution of the diseaseDistribution of the disease

Trypanosoma brucei:Two different parasites

African Sleeping Sickness is caused by two different parasites.



African Sleeping Sickness is caused by two different parasites. Trypanosoma brucei gambienseTrypanosoma brucei rhodesiense



Trypanosoma brucei gambienseAccounts for 90% of reported

cases of African Sleeping Sickness.

Causes the chronic form of the disease

Prevalent mostly in West and Central Africa.



http://www.dmacc.cc.ia.us/instructors/Image11.gif


Trypanosoma brucei rhodesiense Accounts for 10% of

reported cases of African Sleeping Sickness.

Causes the acute form of the disease.

Prevalent mostly in Eastern and Southern Africa.



http://www.uoguelph.ca/~pwoo/fig6.jpg

Method of Infection

Begins with the bite of the tsetse fly

http://www.who.int/mediacentre/factsheets/fs259/en/ http://www.mimg.ucla.edu/faculty/Hill/fig2.jpg

Method of Infection

The bite will become red and swollen.


http://io.uwinnipeg.ca/~simmons/16cm05/1116/28-11-TrypanosomaLM.jpg

Method of Infection


From here, the infection will enter the bloodstream.


http://io.uwinnipeg.ca/~simmons/16cm05/1116/28-11-TrypanosomaLM.jpg

Method of Infection


The infection will enter the bloodstream.

Long asymptomatic phase.

http://www.who.int/mediacentre/factsheets/fs259/en/http://io.uwinnipeg.ca/~simmons/16cm05/1116/28-11-

TrypanosomaLM.jpg

The disease has three distinct stages.

The disease has three distinct stages. Asymptomatic Phase


The disease has three distinct stages. Asymptomatic Phase First Stage (haemolymphatic phase)


The disease has three distinct stages. Asymptomatic Phase First Stage (haemolymphatic phase) Second Stage (neurological phase)


First Stage

The pathogens will spread throughout the blood and the lymph.


http://www.pnas.org/content/100/3/F1.medium.gif

First Stage

Symptoms Fever Headache Sweating Joint Pain Itching Swollen Lymph Nodes

www.who.int/mediacentre/factsheets/fs259/en http://upload.wikimedia.org/wikipedia/commons/thumb/8/88/Winterbottom%27s_sign.jpg/200px-Winterbottom%27s_sign.jpg

Second Stage

Eventually, the disease will manage to cross the blood-brain barrier.

Second Stage

Eventually, the disease will manage to cross the blood-brain barrier.

This will cause an infection of the Central Nervous System

www.who.int/mediacentre/factsheets/fs259/en

Second Stage

Symptoms Confusion Sensory

Disturbances Poor Coordination Disturbances of

Sleep Cycles


http://www.msf.org.uk/UploadedImages/e64ac496-41d9-4b8b-8cac-423baecb957f.jpg

If not treated, the disease is fatal.


Diagnosis and Treatment

Treatment varies depending on the stage of the disease.


http://www.sawitfirst.co.uk/media/pill_clockbig.gif


The disease is easier and more effective to treat the earlier it is diagnosed.



The disease is easier and more effective to treat the earlier it is diagnosed.

Much harder after the pathogens have crossed the blood-brain barrier.



Four drugs are available for treatment

http://www.pet-comfort-products.com/images/colorful-pills-01.gif


Four drugs are available for treatment Two available for first-

stage treatment Two available for

second-stage treatment



www.pet-comfort-products.com/images/colorful-pills-01.gif


The two drugs available for second-stage treatment are significantly more dangerous.



So, in summary, treatment during the first-stage is…


So, in summary, treatment during the first-stage is… More effective

http://images.the-scientist.com/content/figures/images/yr2002/may13/iv.jpg


So, in summary, treatment during the first-stage is… More effective Safer

http://images.the-scientist.com/content/figures/images/yr2002/may13/iv.jpg


Therefore, early diagnosis is imperative


http://www.bayerscheringpharma.de/html/images/upload/gesellschaftliches_engagement/aerztin_patient_205.jpg

Like with malaria, if we could reduce the number of people with the disease, we could reduce transmissions and eventually eradicate the disease.

http://www.ecdl.com/countries/images/map_africa.gif

Organizations like WHO have began efforts to eliminate the risk of this disease



Organizations like WHO have began efforts to eliminate the risk of this disease

HAT programme



Due to lack of funds and turmoil, there are an estimated 7 nations currently at “epidemic” level for the disease.

http://www.kfwh.org/information.asp

Like many other infectious diseases in third world countries, much change is needed in world health policies before we can effectively eradicate African Sleeping Sickness.

THE END.

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ANDREA BRADY BIOL 062 African trypanosomiasis (Sleeping Sickness)