Infectious Disease Compendium

Chagas disease

Diagnosis

From a protozoan, Trypanosoma cruzi. The clinical syndrome of Chagas includes

- Acute Chagas' disease: a chagoma (an indurated area of erythema and swelling with local lymph node involvement. The Romaña sign consists of painless edema of the palpebrae and periocular tissues; then fever, malaise, anorexia, and edema of the face and lower extremities, sometimes with generalized lymphadenopathy and mild hepatosplenomegaly. Encephalitis and myocarditis may also occur early.

- Chronic Chagas' disease: occurs years after the initial infection with cardiomyopathy and megaesophagus, chronic constipation and abdominal pain.

Pathology and serology are needed to make the diagnosis.

Epidemiologic Risks

Bit by blood-sucking triatomine insects, or kissing bugs, in S. America. There was an outbreak due to drinking contaminated fresh guava juice (PubMed) and acai juice (PubMed).

Curiously, in Arizona, 41.5% of triatomines (the vector of Chaga's) were infected with T. cruzi (PubMed). However, the bugs in Arizona do not feed on humans. It turns out the US South is rife with Chagas and they are feeding on humans, indoor and out (PubMed). It has been spread in S. California (PubMed).

Chagas is spread when the triatomine feeds and at the same time takes a crap. The human then itches, driving the bug crap into the skin along with the Chaga's. In the US the triatomine is more fastidious, leaving its feeding site before taking a crap. Perhaps this is why there is less Chaga's in the US.

In Texas, one in 6,500 tested positive for the Chagas, much higher than the usual one in 300,000 of the CDC. So there may be more Chaga's in the US than we are aware. And reports of disease in Texas go back to 1935 (PubMed).

The rates in those born south of the border in LA are 1.24% with different countries of origin at different risks (PubMed).

Microbiology

From a protozoa, Trypanosoma cruzi.

Empiric Therapy

Acute nifurtimox 8 to 10 mg/kg body weight/day; perhaps benznidazole 5 mg/kg/day for 30 days leads to less long term disease (PubMed).

Chronic Chaga is benznidazole, you have to get it from the CDC.

Pearls

It can be spread by transplanted tissues.

Since the fall of 2014 serology is done as part of blood donation, so expect the occasional case. The CDC will assist in confirmation serology as well as acquiring medications.

Curious Cases

Relevant links to my Medscape blog

The Bird That Wasn't There.

Something Parasitic This Way Comes

Last Update: 06/08/18.