2008 - Communication Across the Curriculum (CAC)

B i o l o g y
of the parasite gets out in the stools.
When the bug bites an animal
or a human, at the same time it
deposits the stools infected with the
protozoan, which can enter the body
of the victim through small lesions
or through mucous membranes
(Restrepo et al 604).
Affect on body
When the parasites penetrate the Figure 1. T. cruzi invading red blood cells.
skin barrier, they invade reticular
http://images.google.com/
cells, where they reproduce as
amastigotes. They can also invade
adipose cells and muscular fibers of the subcutaneous tissue.
They invade regional nodes which are then blocked due to
inflammatory reaction and grow in size. From the nodes, they
invade other organs such as the lungs, spleen, liver, bone
marrow, heart, digestive tube, and brain (Restrepo et al 605).
The disease has three phases: acute, asymptomatic, and
chronic. The incubation period varies between 2-4 weeks and
sometimes more. Frequently, the acute phase is not noticed.
It’s easier detected in children under 10. There’s a lesion where
the parasite enters the body which is known as chagoma. In
the acute phase there’s very high parasitemia and there’s the
possibility of quick cardiac invasion which produces myocarditis
and cardiac failure, followed by death of the patient (Bastien 18).
Symptoms of this phase are high fever, shivering, and soreness.
After the acute phase, the parasite enters the latent phase with
low parasitemia. This phase can last up to 20 years. It starts
after the 8th to 10th week of infection and it’s followed by the
chronic phase (Montoya 232).
In the chronic phase, the principal pathology occurs in the
heart. The parasite reproduces within the muscle fibers and
accumulates as amastigotes, producing inflammation in different
cell types. In this phase there are not as many parasites as in the
acute phase, but the inflammation persists and the heart ends in
cardiomegalia with ventricular hypertrophy and apical aneurysm,
in particular the left ventricle (Figure 2). What happens is that the
myocardium of the left ventricle thickens due to the presence
of the reproducing parasites. This leads to an increase of
1 1
W r i t i n g A c r o s s t h e C u r r i c u l u m