Trypanosomiasis - Peru (Oxapampa)

International Society for Infectious Diseases
<http://www.isid.org>


During the 1st week of August 2006, in San Bartolome Mother-and-Child
Hospital in Lima, a case of Chagas' disease was diagnosed in a
6-year-old girl from Pozuzo District, Oxapampa Province, Pasco
Department in Peru, the very 1st case from an area not previously
recognized as endemic for Chagas' disease.

The case was confirmed in the Chagas and Leishmaniasis Laboratory in
Peruvian National Institutes of Health. It is a case of acute Chagas'
disease, characterized by febrile illness of one month duration and
hepatosplenomegaly with no inoculation chagoma (the typical mass
indicating inoculation). Thick blood smears performed as part of
routine screening for malaria showed a high _Trypanosoma cruzi_
parasitemia. Before being diagnosed, the girl was examined by
different physicians, both in her [home town] as well as in Lima, and
nobody ever thought of Chagas' disease, since the Peruvian Central
Jungle had been considered a non-endemic zone for this disease.

Pozuzo is located in the so-called Selva alta (highland jungle) in
Peru, 800 meters above sea level, on the eastern side of the Andes
mountains. The area has a humid tropical climate. This case is the
very first report of Chagas' disease from this Peruvian region.

In Peru, Chagas' disease is endemic in 3 regions: southwest,
including Arequipa, Moquegua, Tacna, and Ica Departments, sharing
characteristics with Northern Chile and Bolivia, since _Triatoma
infestans_ is the only recognized vector; the Northeastern area,
including coastal regions from La Libertad, Lambayeque, Piura, and
Tumbes Departments, where [house-based] vectors such as _Rhodnius
ecuadoriensis_ have been identified; and the third area corresponds
to the Northeastern region, including Amazonas, Cajamarca, and San
Martin Departments, all of them in the basins of rivers tributary of
Amazonas river, where the most important vector is _Panstrongylus
herreri_, which also colonizes households.

During a visit to the Pozuzo region, _Panstrongylus geniculatus_ was
found, a vector that apparently does not colonize households, but it
enters the houses at night, attracted by light bulbs, and it bites
people while they sleep. In the house of the patient, _P.
geniculatus_ specimens were found at night, but all of them tested
negative for members of the _Trypanosoma_ family. In the serological
study performed on all family members and neighbours (14 persons), no
other person seropositive to Chagas' disease was found.

In a survey performed in other 44 adult persons in Pozuzo District,
it was determined that this vector has been detected for
approximately 30 years, and it is identified as "chirimacha", a
popular term used in Southern Peru for _Triatoma infestans_. This
vector is the one with the widest distribution in the Americas; it
has been found from Northern Argentina to Mexico and the Caribbean
Islands, and it is associated with wild animals' burrows, but this
vector now is becoming a domiciliary vector; in some areas in Brazil,
Venezuela, and Colombia, household colonization by _P. geniculatus_
has been reported in association with deforestation.

The girl has [is expected to have] a favourable outcome; she received
benznidazole, 7.5 mg/Kg/day for one month. Fever subsided on the 10th
day of therapy.

--
Dr. Carlos Alberto Mendoza-Ticona
Silvia Vega-Chirinos, Biologist
Professor Cesar Naquira-Velarde

The Pan American Health Organisation estimates that "A total
population of 600 000 is estimated to live in areas of Chagas disease
transmission. In 1999, the screening of donated blood yielded a rate
of 0.8 percent positive results.
<http://www.paho.org/english/dd/ais/be_v25n3-profile-peru.htm>).

The present report indicates that the area with risk of infection
with _Trypanosoma cruzi_ in Peru needs to be redefined and the
population numbers at risk increased.