Transfusion transmitted infection
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A transfusion transmitted infection (TTI) is a
Preventing the spread of these diseases by blood transfusion is addressed in several ways. In many cases, the blood is tested for the pathogen, sometimes with several different methodologies. Donors of blood are also screened for signs and symptoms of disease and for activities that might put them at risk for infection. If a local supply is not safe, blood may be imported from other areas.
Blood that is processed into medications by
Viruses
Many of these viruses are controlled through laboratory screening tests. These fall into three basic varieties:
High risk activities for transfusion transmitted infections vary, and the amount of caution used for screening donors varies based on how dangerous the disease is. Most of the viral diseases are spread by either
Whether a donor is considered to be at "too high" of a risk for a disease to be allowed to donate is sometimes controversial, especially for sexual contact. High risk sexual activity usually includes:
- Sex in exchange for money or drugs.
- controversialcriterion.
- A recent history of sexually transmitted infection.
- Sex with a person who has had a positive test or was at high risk for a disease that can be spread in blood transfusions.
HIV
The virus that causes
The standard test for HIV is an
In addition to the general risk criteria for viruses, blood donors are sometimes excluded if they have lived in certain parts of Africa where subtypes of HIV that are not reliably detected on some tests are found, specifically HIV group O. People who have been in prison for extended periods are also excluded for HIV risk.
Hepatitis A
- Not a major concern, viremic donors are often obviously ill, not a chronic disease.
- Recipients of blood-derived clotting factor concentrates have become ill with Hepatitis A, but there are no documented cases of the disease being transmitted in transfused blood.[1]
Hepatitis B
- The first virus routinely screened in blood donations.
- Delta agentnot screened for, since it is a superinfection of Hepatitis B and cannot exist alone.
Hepatitis C
- Often silent infection
- Most likely significant TTI in developed countries
Alanine transaminase (ALT)
- Used as a surrogate for other Hepatitis testing, losing favor now that HCV tests have improved
Human T-Lymphotropic Virus (HTLV I/II)
- "HTLV III"
Cytomegalovirus (CMV)
- Not relevant unless recipient's immune system is compromised (i.e. infants).
West Nile virus
- is Japanese encephalitis a possible TTI?
- Pool vs. individual testing.
Simian foamy virus (SFV)
- Not known to cause disease, recent studies
SARS
- Donors screened
- No demonstrated transmission, hypothetical risk
- No resurgence of disease
Parasites and specific bacteria
Malaria (Plasmodia spp.)
- Tests exist, but they are not very good.
- Endemic in many areas of the world.
- Only relevant for red blood cell transfusions.
Babesiosis
Babesia microti is transmitted by ixodes ticks and causes babesiosis. Transfusion-associated babesiosis has been documented.[2][3]
Chagas disease
- New test in use
Leishmaniasis
- Donors screened, problem for donors who have been to Iraq.
Syphilis
- Does not survive at refrigerated temperatures
- Used as test for high-risk sexual behavior
Lyme disease
- No cases have been reported, but the CDC urges caution due to a theoretical risk.[4]
Other bacteria
Skin flora
Bacteremia and platelets
- Testing
- Part of the reason that platelet shelf life is so short
Variant Creutzfeldt–Jakob disease (vCJD)
- "Mad Cow"
- UK imported plasma for transfusion[5]
See also
References
- ^ "Transfusion transmitted injuries". Public Health Agency of Canada. Retrieved 2009-01-16.
- PMID 33252652.
- S2CID 207536359.
- ^ "Lyme disease FAQ". Centers for Disease Control and Prevention. 8 January 2021. Retrieved 28 April 2022.
- ^ "UK buys "safe" blood supply for NHS". British Broadcasting Corporation. 2002-12-17. Retrieved 2008-06-01.