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).
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.
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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