African Trypanosomiasis



African Trypanosomiasis



African Trypanosomiasis
  Non-vector borne  
African Trypanosomiasis  

Summary of Basic Science and Clinical Information for American Trypanosomiasis

(Chapter 7 from: Parasitic Diseases 5th Ed.)

Section 1



ProMED Updates

Trypanosoma cruzi, Autochthonous - Louisana

Mar 14, 2007
Dorn PL et al. Emerg Infect Dis, April 2007

Autochthonous transmission of the Chagas disease parasite, Trypanosoma cruzi, was detected in a 74-year-old female patient in rural New Orleans, Louisiana in July 2006. The patient had positive test results from 2 serologic tests and hemoculture; 56 percent of 18 Triatoma sanguisuga collected from the house of the patient were positive for T. cruzi by PCR.

Only 5 autochthonous cases of infection with the Chagas disease parasite have been reported in the United States: 3 in infants in
Texas (2,3), 1 in an infant in Tennessee (4), and 1 in a 56-year-old woman in California (5). The most important triatomine pecies in the United States for Chagas disease transmission are Triatoma sanguisuga, (click here for a photo) whose broad range extends across the southeast and reaches Maryland and Texas, and T. gerstaekeri, found in Texas and New Mexico (6). There is an active sylvan cycle in the United States; T. cruzi has been identified directly or by serologic analysis in >18 species of mammals (7), including raccoons, opossums, armadillos, foxes, skunks, dogs, wood rats, squirrels, and nonhuman primates (housed in outdoor research facilities). In Louisiana, T. cruzi infection has been identified in 28.8 percent and 1.1 percent of armadillos (8,9), 37.5 percent of opossums (9), 4.7 percent of rural dogs (10) and rarely in nonhuman primates (11, P.L. Dorn et al., unpub. data). The lack of human cases is usually attributed to not having a suitable habitat for the bugs in most US homes, a preference for animal hosts, and delayed defecation of triatomines found in the United States compared with those found in Latin America (12).

The Study

In June 2006, a 74-year-old woman residing in a house in rural New Orleans was bothered by a considerable number (more than 50) of insect bites. The woman observed many bugs in the house and showed them to a fumigator, who identified them as triatomines. An internet search showed the potential for transmission of Chagas disease, and the woman sought help from a local health sciences center.


The assertion that the patient contacted T. cruzi in Louisiana is strongly supported by limited travel history to disease-endemic areas and stays mostly in improved housing (risk for Chagas disease transmission is associated with longer residence in disease-endemic areas), lack of other risk factors, and large numbers of infected T. sanguisuga in the house. No periorbital swelling was reported. However, the streaks on her nightgown consistent with triatomine feces indicate exposure, and the parasite could have been introduced into any of her numerous bite wounds.

The residents had not previously noticed large numbers of T. sanguisuga in the house. However, Hurricane Katrina had hit the area 9 months earlier, and increases in domestic infestation with triatomines have been previously reported after a hurricane (15).
Anecdotally, the armadillo population increased substantially in the months after Hurricane Katrina, and one can speculate that these hosts supported a larger bug population, who later sought other bloodmeal sources as the armadillo population returned to pre-storm levels. Follow-up studies of local T. sanguisuga ecology and animal reservoirs are planned.


1. Morel CM, Lazdins J. Chagas disease. Nat Rev Microbiol. 2003;1:14-5.
2. Woody NC, Woody HB. American trypanosomiasis (Chagas' disease); 1st indigenous case in the United States. JAMA. 1955;159:676-7.
3. Ochs DE, Hnilica VS, Moser DR, Smith JH, Kirchhoff LV. Postmortem diagnosis of autochthonous acute chagasic myocarditis by polymerase chain reaction amplification of a species-specific DNA sequence of Trypanosoma cruzi. Am J Trop Med Hyg. 1996;54:526-9.
4. Herwaldt BL, Grijalva MJ, Newsome AL, McGhee CR, Powell MR, Nemec DG, et al. Use of polymerase chain reaction to diagnose the fifth reported US case of autochthonous transmission of Trypanosoma cruzi, in Tennessee, 1998. J Infect Dis. 2000;181:395-9.
5. Schiffler RJ, Mansur GP, Navin TR, Limpakarnjanarat K. Indigenous Chagas' disease (American trypanosomiasis) in California. JAMA. 1984;251:2983
6. Lent H, Wygodzinsky P. Revision of the Triatominae (Hemiptera, Reduviidae) and their significance as vectors of Chagas disease.
Bulletin of the American Museum of Natural History. 1979;163:123-520.
7. John DT, Hoppe KL. Trypanosoma cruzi from wild raccoons in Oklahoma. Am J Vet Res. 1986;47:1056-9.
8. Yaeger RG. The prevalence of Trypanosoma cruzi infection in armadillos collected at a site near New Orleans, Louisiana. Am J Trop Med Hyg. 1988;38:323-6.
9. Barr SC, Brown CC, Dennis VA, Klei TR. The lesions and prevalence of Trypanosoma cruzi in opossums and armadillos from southern Louisiana. J Parasitol. 1991;77:624-7.
10. Barr SC, Dennis VA, Klei TR. Serologic and blood culture survey of Trypanosoma cruzi infection in four canine populations of southern Louisiana. Am J Vet Res. 1991;52:570-3.
11. Seibold HR, Wolf RH. American trypanosomiasis (Chagas' disease) in Hylobates pileatus. Laboratory and Animal Care. 1970;20:514-7.
12. Zeledon R. Epidemiology, modes of transmission and reservoir hosts of Chagas' disease. In: In Elliot K, O'Connor M, Wolstenholme GF, editors. Trypanosomiasis and leishmaniasis with special reference to Chagas' disease. Amsterdam: Associated Scientific Publishers; 1974. p. 51-85.
13. Yabsley MJ, Norton TM, Powell MR, Davidson WR. Molecular and serologic evidence of tick-borne ehrlichiae in three species of
lemurs from St. Catherines Island, Georgia, USA. J Zoo Wildl Med. 2004;35:503-9.
14. Dorn PL, Engelke D, Rodas A, Rosales R, Melgar S, Brahney B, et al. Utility of the polymerase chain reaction in detection of
Trypanosoma cruzi in Guatemalan Chagas' disease vectors. Am J Trop Med Hyg. 1999;60:740-5. 15. Guzman-Tapia Y, Ramirez-Sierra MJ, Escobedo-Ortegon J, Dumonteil
E. Effect of Hurricane Isidore on Triatoma dimidiata distribution and Chagas disease transmission risk in the Yucatan Peninsula of Mexico. Am J Trop Med Hyg. 2005;73:1019-25.


It is highly plausible that the patient was indeed infected in Louisiana, and even a single case like this demonstrates that there must be an animal reservoir of Trypanosoma cruzi in the locality. Previous work (cited above in the references) has demonstrated T. cruzi in Louisiana armadillos, possums and dogs. It should be noted that transmission to humans requires bites by infected triatomid bugs, which usually live in cracks in house walls. It is a typical disease of poverty and poor living conditions. Further studies of the animal reservoir and vector are needed.

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