The Corpus Christi-Nueces County Public Health District is retracting the confirmed case of Chagas and downgrading it from confirmed to probable. As a probable case it is considered non-confirmed because it does not meet the case definition as stated below:
The case definition for a probable case classification includes: A physician diagnosed case of chronic Chagas disease in a patient that is older than nine months of age with supportive laboratory obtained more than eight weeks after a documented exposure or symptom onset.
The supportive lab testing for a confirmed case is either a positive diagnostic serology for Trypanosoma cruzi antibodies, or a positive blood donor screening test with a positive supplemental test. The documented exposure may include history of travel to an endemic country such as Mexico, or any one in Central or South America.
According to health officials, a blood donor was screened for Chagas and returned a positive result. However, the case cannot be confirmed until a follow up test comes back with a positive result. The Health District was unable to locate the donor that was listed as positive and are unable to draw a second test. Due to the lack of the second positive screen the case is non-confirmed and now “probable” but not a confirmed case.
As a matter of public safety, the Coastal Bend Blood Bank reports that any positive test from a blood donor is discarded and never used for donation.
For more information on Chagas disease you can go to the following web pages:
The Centers for Disease Control and Prevention web page
The World Health Organization web page at http://www.who.int/mediacentre/factsheets/fs340/en/.