What’s In a Name? Chikungunya and Dengue Viruses and the Blood Supply

“Incurable Virus Spreads in US!” In recent weeks, breathless and scary-sounding headlines like this have been seen in newspapers and web sites in the United States, describing an outbreak of emerging viruses with scary names like “Chikungunya” and “Dengue” seen in US travelers to the Caribbean, South America, and other tropical areas. While the news certainly sounds terrifying to the public, Transfusion Medicine professionals must evaluate donors carrying these “emerging” infections (defined as infections whose human incidence has increased in the last 20 years or so) as scientifically as possible to ensure the maximum safety of the blood supply. Let’s take a quick look at two of these infections and their implications for potential blood donors.

Chikungunya virus:

Chikungunya has quite possibly the greatest name in the history of viruses! Sadly, it is a fun-sounding name for a not-so-fun disease. This virus has been on our radar for a few years now, as it spread through Africa, Southeast Asia and parts of Europe. More recently, however, Chikungunya has become quite prominent in the Caribbean islands as well as Central and South America.

  • Vector: Aedes species mosquitoes
  • Spread: Human to human via mosquito vector
  • Illness: High fever, severe joint pain that may last months, severe infections in already ill adults or neonates
  • Treatment: No specific therapy or vaccine; just support symptoms
  • Blood transmission: No cases reported, though theoretically possible
  • Tests for donors: None approved by FDA

Though the CDC is monitoring numerous cases of Chikungunya in US citizens in multiple states exposed through mosquito bites during travel, we currently do not have great ways to track or test blood donors. Fortunately, at least 80% of people infected with this virus are symptomatic, and as a result, would be deferred from blood donation simply because they don’t feel well.

Dengue:

Dengue is another emerging infection that has been recently seen in US citizens, primarily those who travel to Asia and South America (in fact, according to the February 2014 update to the AABB Dengue virus fact sheet, Dengue is the most frequent cause of fever in US travelers returning from those areas; source: AABB web site). Worldwide, Dengue is a MASSIVE problem, affecting millions and killing over 22,000 people every year (source: CDC Dengue web site).

  • Vector: Aedes species mosquitoes
  • Spread: Human to human via mosquito vector
  • Illness: High fever, rash, headache, severe lower back pain known as “break-bone fever”; Rare cases with hemorrhagic or shock
  • Treatment: No specific therapy or vaccine; just support symptoms
  • Blood transmission: Multiple well-proven transmissions from RBCs, platelets, and plasma
  • Tests for donors: None approved by FDA

Dengue and Chikungunya infections can present in a very similar manner (high fever and joint pain). Dengue, however, is associated with much more severe consequences in a few patients, with diffuse hemorrhage and complete systemic collapse seen in a few patients.

Together, these viruses infect millions of people around the world every year. However, to date, neither has proven to be a large issue in US blood donors. In addition to the fact that potential blood donors infected by either virus will often be deferred because they do not feel well, many will also be prohibited from donating because they have traveled to an area where malaria is endemic (the malaria travel deferral covers much of the distribution area for both Dengue and Chikungunya).

It is clear to all Transfusion Medicine professionals that we are not completely “safe,” even though we have not yet seen an abundance of transfusion transmission of Dengue, and none whatsoever with Chikungunya. The presence of these non-treatable infections is simply another reminder that transfusion has risks aside from the ones that clinicians and patients think about most (HIV and hepatitis, for example). A big part of the job of a Transfusion Medicine professional is to help our clinician friends ensure that transfusions are only given when absolutely necessary.

 

Chaffin

Joe Chaffin, MD, is the new Vice President and Chief Medical Officer for LifeStream, a Southern California blood center headquartered in San Bernardino, CA. He has a long history of innovative educational efforts and is most widely known as the founder and chief author of “The Blood Bank Guy” website (www.bbguy.org).

 

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