Chagas Disease Tabitha Martel Epidemiology November 15, 2007.

Chagas Disease

Tabitha MartelEpidemiology

November 15, 2007

The Basics

• Chagas disease is a parasite contracted through fecal matter from an insect ( “kissing bug”) and the insect bite.

• Transferred to both animals and humans.• This disease is most commonly found within

North, South, and Central America. • It occurs in two phases, acute and chronic.

http://www.cdc.gov/chagas/epi.html

Transmission

• There are multiple methods of transmission.– Agent -> host via broken skin– Through blood transfusion– Organ transplant– Fecal to skin– Mother to baby (congenital)

http://www.who.int/tdr/diseases/chagas/files/chagas-poster.pdf

Signs and Symptoms

• Acute Phase (a few weeks to a few months)– Sight swelling– Visible sore– Fever– Swollen Lymph nodes– Death (in children)– Swelling of the heart and brain cavity (rare)

http://www.cdc.gov/chagas/disease.html

Signs and Symptoms

• Chronic Phase– Heart rhythm abnormalities– Dilated heart– Dilated esophagus– Dilated colon

• People with compromised immune systems are more susceptible to the reoccurring, chronic, life threatening symptoms.


Statistical Analysis

• As reported by the World Health Organization– 210,000 deaths annually– At risk population:120 Million, 300,000new cases

each year– Of the at risk population, 16-18 million people are

currently infected.


Contributing Factors

• Poorly made houses– Mud houses, cracks and crevices provide

adequate housing for the insect.

• Underdeveloped countries do not have the screening processes in place to screen out infected organs and blood


Web of Causation

Chagas Disease

AcuteFever

SwellingHeart/brain/lining

death

ChronicHeart abnormalities

Dilated heart/esophagus/colondeath

Months-life

Weeks-monthsWHO?

Residents of north, south & central America and Mexico in poor housing conditions especially un rural areas

DiagnosisObservation via blood smear

(acute)Agent Isolation

TransmissionInsect

TransfusionsOrgan transplantFecal-skin contact

Mother-baby

Why?Underdeveloped technology,

resources

PreventionBug Bombs

New housingBetter screening

WhyFriendly environment for the

insect

Chain of infectionPoorly constructed housing unit provides shelter for insect

Insect bites human/House not treated with insecticide

Individual becomes infected

Individual spreads disease through a blood transfusion/organ transplant

Focus Region

• Geographical region of interest– Central America• In an attempt to remain as close to “home” as possible

while still maintaining a large number of infected people as well as those at risk.


Hypothesis

• Educate on the importance of “bug bombing” residences.– Break the cycle by eliminating the insects from the

housing areas, by creating an unsuitable environment with the help of the insecticide.

• By applying insecticide once a month to each at-risk housing unit in rural central America for two years there will be a decrease in Chagas Disease.


Break it Down…

• Exposure: Monthly “bug bombs”• Health-Outcome: Significant decrease of

disease after two years of exposure• Dose: One application every month for two

years• Time-response: There will be a decrease after

two years from the start of the program• Population: People living in Central America,

in rural areas in houses less than satisfactory.


Causation Evaluation

• Strong correlation between the exposure and outcome.– Chain of infection is broken with the removal of the

insect• Similar programs in place currently to urge

communities to use insecticide• Once a month applications for two years is

adequate time to see a response.• This program is an analytical intervention

community trial.

Final Thought

• Designated by WHO to be eradicated by 2010

References

Chagas Disease. (n.d.). Center for Disease Control. Retrieved November 15, 2007, from http://www.cdc.gov/chagas/

Tropical Disease Resources. (n.d.). World Health Organization. Retrieved November 15, 2007, from http://www.who.int/tdr/diseases/chagas/files/chagas-poster.pdf

Chagas Disease Tabitha Martel Epidemiology November 15, 2007.

Documents

Transcript of Chagas Disease Tabitha Martel Epidemiology November 15, 2007.