[TDI-discuss] TRYPANOSOMIASIS, FOODBORNE - SOUTH AMERICA

["Dr. Alfonso J. Rodriguez" <>]

Archive Number 20050327.0884 
Published Date 27-MAR-2005 
Subject PRO> Trypanosomiasis, foodborne - South
America (03) 


TRYPANOSOMIASIS, FOODBORNE - SOUTH AMERICA (03)
***********************************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>

Date: Sun 27 Mar 2005
From: Luiz Jacintho da Silva
<>
Source: Fiocruz.br [translated from Portuguese by
Mod.LJS, edited]
<http://www.fiocruz.br/ccs/novidades/dez04/chagas_fer.htm>


Study confirms a different form of Chagas?
disease transmission
-----------------------------------------------
When one hears of the transmission of the 
protozoan _Trypanosoma cruzi_, the 1st thing that 
comes to the mind is the Reduviid bug vector. 
This insect, when biting an individual, 
eliminates parasite-contaminated feces that, as 
the individual scratches himself, penetrates 
through abraded skin or mucosa [intact]. This is 
the most common route, but the occurrence of 
certain outbreaks has led scientists to consider 
the possibility of oral transmission of _T.cruzi_.

A study by the Goncalo Muniz Research Center, a 
FIOCRUZ unit in Bahia, presents evidence that 
this protozoan can indeed be transmitted by the 
ingestion of contaminated food [or beverages]. On 
Sun 20 Mar 2005, an episode in Santa Catarina 
confirmed the results of the research.

The deaths of 3 [now 5] persons, and the report 
of another 15 cases of the disease in the state, 
have led health authorities in the state to 
prohibit the sale of sugarcane juice. The 
infection seems to have been transmitted by this 
beverage.

In 1968, a member of a farming community in 
Teotonia (Rio Grande do Sul) fell ill with a 
severe febrile illness. No one suspected Chagas 
disease, as there were no Reduviid bug vectors in 
the local dwellings. After much investigation, 
food borne transmission through vegetables served 
in the common dining-room was accepted as the 
cause. Possibly, marsupials had contaminated the 
vegetables by droppings from their anal glands, 
usually rich in _T.cruzi_.

Years later [1986], another outbreak occurred, 
this time in Catole do Rocha (Paraiba). A large 
wedding anniversary party had been held on a 
farm. Days later, some of the guests fell ill 
with a febrile illness, similar to the one in 
Teotonia. Sugarcane juice and other foodstuffs or 
beverages had been contaminated by animal 
droppings. The couple that had celebrated their 
50th anniversary eventually died as a consequence 
of Chagas disease acquired at the party.

Recently, oral transmission of _T. cruzi_ has 
been responsible for small outbreaks in the state 
of Para. Entire families acquired Chagas disease 
in the absence of insect vectors in their homes. 
These insects live in palm trees and, attracted 
by the lights, fall into the machinery used to 
grind acai to obtain juice (much the way 
sugarcane juice is obtained). The insects are 
ground and contaminate the juice with _T. cruzi_, 
transmitting the infection to those drinking it.

All of these cases in Rio Grande do Sul, Paraiba 
and Para attracted the attention of scientists. 
The question which was brought forward was why 
didn't gastric juice destroy _T. cruzi_? The 
physician Sonia Gomes Andrade from CPqGM, who 
specializes in experimental pathology, formulated 
an experiment:

- We introduced _T. cruzi_ through a tube 
directly into the stomach of mice, she says. She 
studied the strains isolated from cases in 
Paraiba and Para.
- We observed that the parasite not only survived 
gastric juice but was able to infect the mice. 
They developed disease identical to the one 
produced when mice are infected directly via the 
bloodstream. The findings of the researcher 
confirm that _T. cruzi_, when swallowed, can 
cause infection through the digestive system.
- In the most common manner of infection, 
scratching, _T. cruzi_ is able to penetrate the 
skin. [It is easy to] imagine [that], when 
someone ingests a large quantity of parasites, 
the [infection] will be more severe, says Sonia. 
The researcher stated that there is no reason to 
stop eating vegetables or drinking sugarcane or 
acai juice.
- The problem lies not with the kind of food but 
with _T. cruzi_. These are mainly parasites of 
biodem type III -- from wildlife -- that are able 
to cause infection through the digestive system. 
A biodem is a group of [genetically close] 
_T.cruzi_ strains with similar characteristics. 
Biodem type III strains are, as a rule, highly 
pathogenic. In the experiment, a strain of this 
type showed a higher capacity to cross the 
gastric barrier and cause infection in mice than 
strains from biodems I and II.
- It is significant to point out that biodem III 
strains are associated with wildlife disease 
cycles, causing outbreaks in places where 
Reduviid bugs are not domiciled.

--
ProMED-mail
<>

[It seems beyond doubt that _T. cruzi_ can infect 
hosts, including humans, by the oral route, but 
it still remains unclear how important this route 
of transmission is for maintaining infections in 
humans and causing outbreaks like the present 
one. The mouse experiment cited above confirms 
previous reports [cited in ProMED-mail, 
Trypanosomiasis, foodborne - South America 
20050324.0847; Hoft et al. Infect Immun 
1996,64:3800-10] that _T. cruzi_ can indeed 
infect the host through the gastric mucosa. The 
key question is how long a time _T. cruzi_ can 
survive in feces outside the triatomid bug, and 
how long a time in different forms of fluids 
after the triatomid bugs have been crushed. Oral 
transmission, either from bug feces or from 
crushed bugs, presumes that _T. cruzi_ can 
survive for at least several hours, possibly 
days, in juice. Information on this survival time 
is key to determining whether the present 
outbreak is a rare coincidence or just part of a 
more widespread problem. - Mod.EP]

[see also:
Trypanosomiasis, foodborne - South America (02)
20050325.0870
Trypanosomiasis, foodborne - South America
20050324.0847
1998
----
Trypanosomiasis - Brazil: RFI 19980306.0426
1997
----
Chagas disease - Latin America 19970114.0066
Chagas disease vector (05) 19970118.0105
1996
----
Trypanosomes, New World, Symposium - Guyana 1996
19960830.1493]
...............ep/msp/lm

*##########################################################*
************************************************************
ProMED-mail makes every effort to  verify  the reports
 that
are  posted,  but  the  accuracy  and  completeness 
of  the
information,   and  of  any  statements  or  opinions 
based
thereon, are not guaranteed. The reader assumes all
risks in
using information posted or archived by  ProMED-mail. 
 ISID
and  its  associated  service  providers  shall not be
 held
responsible for errors or omissions or  held liable
for  any
damages incurred as a result of use or reliance upon 
posted
or archived material.
************************************************************
Visit ProMED-mail's web site at
<http://www.promedmail.org>.
Send  all  items  for   posting  to:  

(NOT to  an  individual moderator).  If you do not
give your
full name and  affiliation, it  may  not  be  posted. 
 Send
commands  to  subscribe/unsubscribe,   get  archives, 
help,
etc. to: .    For assistance 
from a
human  being  send  mail  to:  
.
############################################################
############################################################






		
______________________________________________ 
Renovamos el Correo Yahoo!: ¡250 MB GRATIS! 
Nuevos servicios, más seguridad 
http://correo.yahoo.es