On Thursday 14 October 1999 the following e-mail was distributed to our e-network:

"One of our members has asked that the following question be posed to the CBBS e-network. This member lives in an area where the number of Central and South American immigrants is increasing."

Question: In areas with a large immigrant population from Central and South America, is it considered standard practice to use a questionnaire to determine risk, followed by antibody testing if necessary? Different articles use travel to an endemic area for one month versus one year, history of transfusion in the endemic area, type of housing, etc. What are the various institutions represented in the CBBS doing?

And here are the replies (paraphrased) to that e-mail:

1. A blood collection center in Los Angeles stated that they ask the question that is on the universal donor history card which asks the donor whether they have had Chagas' Disease. Their policy is to permanently defer all donors who answer yes (although they have had none). They do not do anything more

2. A blood collection center in San Diego stated that they do not have a large immigrant population from Chagas endemic areas, but they do have large numbers of visitors to those areas. That center only asks the routine question "Have you ever had Chagas disease?". About 5-6 years ago they did a study [probably the one overseen by Dr. Susan Galel of Stanford - see below] in which they used a separate questionnaire concerning visits to the areas, type of housing/huts lived in, whether they received any transfusions while there, etc. They had almost no one out of 2-3000 donors whose answer demonstrated any risk

3. However, another blood banker in San Diego, stated that they do have a rising immigrant population but all they do is ask if the donor has a history of Chagas' disease, and permanently defer for affirmative answers. We based this decision on: 1) Prior donor surveys that revealed quite a low incidence of donors who had lived for longer than a year in primitive (ie mud wall/thatched roof) conditions in the endemic areas; 2) EIA Test (at least when we last looked) complicated by both false-pos. and false-neg. results, with no really good confirmatory assay; and 3) Some experimental evidence that leukoreduction traps the parasites; 4) Despite the influx of immigrants, there has not been an upsurge of cases of transfusion-transmitted Chagas' disease

4. In the study published by Galel and Kirchhoff [Risk factors for Trypanosoma cruzi infection in California blood donors. Transfusion 1996; 36: 227-31] a questionnaire was used to survey donors in 18 California donor centers for risk factors for T. cruzi infection. They discovered that of otherwise eligible allogeneic blood donors (n = 17,521) who completed questionnaires, 427 (2.4%) had lived in endemic areas for more than 1 year, and 39 of these donors had lived in dwellings with mud walls or thatched roofs. Sixteen donors had received transfusions in endemic areas. Six donors gave a history of Chagas' disease. Fifty-seven donors (0.33% of total) had at least one risk factor for T. cruzi infection. Donors at risk for T. cruzi were found in all 18 centers studied, at a median prevalence of 1 per 340 donors. From these data Galel and Kirchhoff concluded that donors at risk for T. cruzi are contributing to the blood supply throughout California. Further consideration should be given to donor screening for this transfusion-transmissible infection

5. A center located in Sacramento stated that in the Sacramento Area, the practice is to neither ask questions nor test for Chagas Disease beyond what is required by Standards

6. A center located in the San Bernardino area is not doing any testing for this infection in donors, as there is no licensed test approved for donor screening, nor is there yet a recommendation or requirement to screen

7. A large blood center in the Los Angeles area states that the FDA would require additional donor testing to be done under an approved IND if the results of this testing were used to determine product suitability. Such testing for T. cruzi antibodies was carried out at several Red Cross blood centers under an approved IND, and the study was completed. Among donors with risk behavior in Los Angeles and Miami confirmed positive test results were found in 1 in 8,000 - 9,000 donors. FDA and test kit manufacturers have been encouraged to pursue FDA licensure of a screening test for Chagas as a higher priority

8. A blood center in the Northern California area uses questions regarding Chagas on the medical history form. If the donor has had Chagas, he/she is permanently deferred. This blood center does not have a separate questionnaire to determine risk

9. According to a major hospital in Northern California, it is NOT standard practice to ask donors about risk factors for T. cruzi infection. None of the questionnaires used in clinical trials in the U.S. have been shown to reduce the risk of T. cruzi transmission. In fact, at least 3 of the studies have shown evidence that risk questionnaires fail to identify some infected donors (In Red Cross trials in CA and in Texas, donors born in the US with no significant travel history were shown to be infected with T. cruzi;. According to this Northern California hospital, Dr. Susan Galel et al at Stanford found that donor answers to the risk questionnaire were very inconsistent from one donation to the next. Thus, the available data suggest that only serological testing would reliably reduce the risk of T. cruzi transmission. However, there is currently no test licensed in the US for this purpose.

Please submit comments to the e-Network Forum.

Ira A. Shulman, MD
CBBS e-Network Forum Editor & Moderator