5-53
Prevention and Hygiene: Avoid insect bites.
Follow-up Actions
Consultation Criteria: All suspected cases should be referred for consultation.
Zoonotic Disease Considerations
Principal Animal Hosts: Dogs, ruminants, carnivores
Clinical Disease in Animals: Intermittent fever, anemia, weight loss; may be asymptomatic.
ID: American Trypanosomiasis (Chagas’ Disease)
LTC Glenn Wortmann, MC, USAIntroduction: Transmitted by kissing bug bite, blood transfusion. Trypanosoma cruzi has been isolated from
many wild and domestic animals from the southern US and through all of Latin America. Incubation period is
5-14 days after bite, 30-40 days after transfusion.
Subjective: Symptoms
Acute: Fever; malaise; red, swollen site of inoculation with an enlarged draining lymph node; unilateral,
painless swelling of eyelid if inoculation was via the eye (Romana’s sign); occasionally, CNS symptoms (e.g.,
seizures) or myocarditis. Chronic: Years later: heart failure; enlargement of the esophagus or colon
Focused History: Do you recall an unusual, red, swollen insect bite or swelling around one eye? (distinctive
bite or Romana’s sign suggestive of Chagas’ disease) Did you ever live in Central or South America?
(endemic to area)
Objective: Signs
Using Basic Tools: Variable fever; lymphadenopathy; Romana’s sign; hard, red, painful nodule (chagoma)
at the bite site.
Using Advanced Tools: Lab: Parasites in peripheral blood smears (thick and thin) can be found during
febrile periods early in the course of infection. (see Color Plates Picture 32)
Assessment:
Differential Diagnosis
Skin lesion (chagoma) - leishmaniasis and bacterial skin infections.
Chronic Chagas’ disease - other causes of heart failure (myocardial infarctions, hypertension), constipation
and dysphagia.
Plan:
Treatment: Acute Chagas’ disease: Nifurtimox or benznidazole from CDC in Atlanta, Georgia (for
investigational use only) and from some hospitals in the endemic area.
Patient Education
General: Prevent insect bites (specifically kissing bugs, which are often found in thatched roofs and bite
at night)
Activity: As tolerated
Diet: As tolerated
Medications: Per CDC guidelines.
Prevention and Hygiene: Avoid insect bites and infested areas; wear protective clothing.