TCMS

PUBLIC HEALTH UPDATE
New Addition to the 2013 Texas Notifi able
Conditions List: Chagas Disease
Philip Huang, MD, MPH
Medical Director/Health Authority
Austin/Travis County Health and Human Services Department
The Texas Department of State Health Services (DSHS)
has posted the Texas Notifi able Conditions for 2013 at
www.dshs.state.tx.us/idcu/investigation/conditions. Chagas
disease, also referred to as American trypanosomiasis, is now a
reportable condition in Texas.
Chagas disease is named after the Brazilian physician,
Carlos Chagas, who discovered it in 1909. Chagas is caused
by the parasite trypanosome cruzi and is transmitted to
animals and people by insect vectors. If infected with the
T. cruzi parasite, triatomine bugs (also called reduviid bugs,
“kissing” bugs, assassin bugs, cone-nosed bugs and blood
suckers) can transmit the parasite during blood meal.
These bugs are present in Mexico, Central America, South
America and the southern United States, including Texas.
DSHS Health Service Region 7 has documented the presence
of the parasite T. cruzi in the triatomine bugs in our area, as
noted in the following preliminary data of Table 1.
Triatomine bugs can live indoors, in cracks and holes of
substandard housing, but are more commonly found outdoors
in a variety of settings. At this time, DSHS, in conjunction
with the CDC, provides testing of triatomine bugs for the
parasite T. cruzi. There currently is no charge for species
identifi cation and testing; due to workload and budget
constraints, testing priority is given to direct implication
in a human exposure. Not all submissions will be tested.
Additional resources on triatomine bug testing can found at
www.dshs.state.tx.us/idcu/health/zoonosis/Triatominae.
The most commonly thought of transmission mode for
Chagas is vector-borne. The disease can also be acquired through
blood transfusion, organ transplant and mother-to-baby
(congenital transmission). Blood banks currently screen for
Chagas disease. Donors are notifi ed when positive testing is
found, and the blood is discarded. The disease process has an
Report Chagas disease to A/TCHHSD
at 512-972-5555 or by
fax at 512-972-5772.
For additional information on chagas disease visit:
DSHS website:
www.dshs.state.tx.us/idcu/disease/chagas
CDC website:
www.cdc.gov/parasites/chagas
incubation period of one to two weeks, acute phase of eight to
12 weeks, indeterminate phase can be years to decades long and
chronic lifelong phase. In the acute phase, most patients are
asymptomatic or mildly feverish, some display infl ammation at
the site of inoculation (chagoma) or unilateral swelling of eyelids
(Romana’s sign). In rare instances, patients present with severe
disease such as myocarditis, pericardial effusion and
meningoencephalitis. Trypomastigotes, circulating in
peripheral blood, can be seen. The early chronic stage or
indeterminate phase is often asymptomatic and prolonged.
During this period, few to no trypomastigotes are found in the
blood. Chronic disease complications include cardiomyopathy,
mega-esophagus, mega-colon and neurological symptoms in
immune-compromised patients. Many people remain
asymptomatic for life. However, it is estimated that 20-30
percent of infected people will develop debilitating and even
life-threatening medical problems over the course of their lives.
Diagnosis of Chagas disease during the acute phase is by
microscopic examination of the parasite in a blood smear. In
the chronic phase, when there are clinical fi ndings and evidence
of exposure, diagnosis is generally made by testing with at least
two different serological tests. Patient testing for Chagas is
available through the CDC. Health care providers may call
Parasitic Diseases at 404-718-4745, email chagas@cdc.gov or
go to private laboratories for testing. Treatment for Chagas
disease is recommended for acute infections, congenital
infections, for those with suppressed immune systems and for
children with chronic infections. Adults with chronic infection
may benefi t from treatment as well. In the United States,
medication for Chagas is available only through the CDC.
Health care providers can discuss with CDC staff whether and
how to treat patients diagnosed with Chagas diseases.
Table 1: Triatomine bugs tested for T. cruzi parasite in Texas Health Service Region 7 Counties
YEAR # TESTED # POSITIVE % COUNTIES
T.cruzi POSITIVE
2012 31 19 61% Blanco (1), Caldwell (6), Fayette (2), Hays (5), Travis(5)
2011 18 10 56% Caldwell (7), Fayette(2), Williamson (1)
2010 1 1 100% Bosque (1)
Note: Individuals with possible exposure to the parasite were advised to seek a medical assessment and testing with their health care
provider. Of those who sought testing, none tested positive for chagas disease.
12 March • April
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