Chagas Disease Tabitha Martel Epidemiology 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.

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

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)

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, 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 Acute Fever Swelling Heart/brain/lining death Chronic Heart abnormalities Dilated heart/esophagus/colon death Months-life Weeks-months WHO? Residents of north, south & central America and Mexico in poor housing conditions especially un rural areas Diagnosis Observation via blood smear (acute) Agent Isolation Transmission Insect Transfusions Organ transplant Fecal-skin contact Mother-baby Why? Underdeveloped technology, resources Prevention Bug Bombs New housing Better screening Why Friendly environment for the insect

Chain of infection Poorly 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 Tropical Disease Resources. (n.d.). World Health Organization. Retrieved November 15, 2007, from