Infectious Disease Compendium

Trypanosoma

Microbiology

A protozoa; Trypanosoma brucei subs. gambiense, Trypanosoma brucei subs. rhodesiense and Trypanosoma cruzi.

One case of T. evansi in Vietnam from slaughtering cows.

There are a variety that have evolved to infect many animals.

Diagnose with Blood smear and lumbar puncture.

Epidemiologic Risks

Trypanosoma brucei subs. gambiense: bit by a tsetse fly in W. Africa.

Trypanosoma brucei subs. rhodesiense: bit by a tsetse fly in E. Africa.

Trypanosoma cruzi: bit by a blood sucking triatomine insects, or kissing bugs in S. America. Many animals serve as a reservoir.

There have beeb outbreaks due to drinking contaminated fresh guava juice (PubMed) and acai, a 'superfood" whose only superpower is giving people Chaga's.  

And perhaps bed bugs (PubMed).

Can be found in semen (the Navy has so many ID issues), so could be an STD (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 usually 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).

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.

Syndromes

Trypanosoma brucei subs. gambiense: Sleeping Sickness; a more chronic form of the illness of months duration with CNS findings late in the course of the disease. It causes chronic illness by changing its outer cell glycoprotein.

Trypanosoma brucei subs. rhodesiense: Sleeping Sickness a more acute form of the illness with CNS finding early.

Trypanosoma cruzi: Chagas.

- 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.

Treatment

Per the CDC

T. b. rhodesiense, hemolymphatic stage Suramin 1 gm IV on days 1, 3, 7 ,14, and 21

T. b. rhodesiense, CNS involvement Melarsoprol 2-3.6 mg/kg/day IV x 3 days. After 7 days, 3.6 mg/kg/day x 3 days. Give a 3rd series of 3.6 mg/kg/d after 7 days.

T. b. gambiense, Hemolymphatic stage Pentamidine 4 mg/kg/day IM or IV x 7-10 days

T. b. gambiense, CNS involvement Eflornithine 400 mg/kg/day in 4 doses x 14 days

Trypanosoma brucei subs. gambiense: "oral fexinidazole is effective and safe for the treatment of T b gambiense infection compared with nifurtimox eflornithine combination therapy in late-stage HAT patients (PubMed)."

Trypanosoma cruzi: acute: Nifurtimox is 8 to 10 mg/kg/day. Nothing works for chronic disease, although benznidazole in adults at 5 to 7.5 mg per kilogram of body weight q day, for 60 days looks promising (PubMed).

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.

Call the Parasitic Diseases Public Inquiries Line (770-488-7775; parasites@cdc.gov; www.cdc.gov/parasites/chagas), the CDC Drug Service (404-639-3670).

Notes

Curious Cases

Relevant links to my Medscape blog

The Bird That Wasn't There.

Something Parasitic This Way Comes

Last Update: 05/01/18.