Tick Parasite in Blood Transfusions
There are a lot of things that can go wrong when you are going to have surgery. But one of the few things that's supposed to be safe is the blood supply, right? After all, blood donations are screened for seven infectious agents, including HIV and hepatitis. But now new research has found that there is a tick parasite that has been transmitted through blood transfusions appearing in the blood supply.
Babesiosis, carried and transmitted by deer ticks throughout the Northeast and northern Midwest United States, is now the most commonly reported infectious agent spread by blood transfusion, according to a study performed at the Centers for Disease Control and Prevention in Atlanta.1 And this is not an infection for which blood donors are being screened.
In their analysis of patient records, the researchers found 162 cases of babesiosis that were transmitted by transfusion between 1979 and 2009. Of those infected, there were 27 fatalities. However, it is not possible at this time to pinpoint how many of them died from the babesiosis as opposed to their previous illness or complications from surgery.
Babesiosis is frequently asymptomatic, so potential blood donors would have no idea that they are harboring a serious infection. When symptoms do appear, they typically include fever, unstable blood pressure and hemolytic anemia brought on by the parasite as it damages populations of red blood cells throughout the body. It is particularly dangerous to those with a weakened immune system, health conditions such as kidney or liver disease, and the elderly. And although it does respond to antibiotics, babesiosis is not something you want spreading among the blood supply to those with already compromised health as they are receiving transfusions.
And let's face it, transfusions themselves aren't the safest procedure to begin with. This website has covered several studies that found that transfusions increase your risk of heart attack and death. The problem lies in the fact that the oxygen-transporting efficacy of stored blood begins to decay almost immediately. This is because stored red blood cells become deficient in nitric oxide, thus limiting their ability to get oxygen to tissues that need it. Nitric oxide opens up blood vessels, which allows oxygen-carrying blood to reach the tissues served by those vessels. Levels of S-nitrohemoglobin (the molecule that carries nitric oxide in the blood) decline rapidly in stored red blood cells. There is a 70 percent drop in the first day of storage. By the twenty-first day, the molecule is below the level of detectability. In the U.S., red blood cells can legally be stored up to 42 days before blood banks are required to discard them.
But it's even worse than that. Because transfused blood is deficient in nitric oxide, it actually sucks nitric oxide out of the surrounding tissue to compensate. This causes that tissue to constrict and become deoxygenated. If that tissue happens to be heart muscle, you have a real problem.
A study from 2007 at Duke University in Durham, North Carolina of more than 9,000 patients has determined that those given blood more than 14 days old are 65 percent more likely to die before discharge and 50 percent more likely to die within a year.2 Recipients of older blood are also at much higher risk of blood poisoning and multi-organ failure according to a 2008 study at the Cleveland Clinic in Ohio.3 Considering the fact that transfused blood usually takes several days to even reach a hospital, the average patient getting a transfusion is quite likely receiving blood that is pushing two weeks old -- with a sizable number receiving blood that is up to four weeks old.
Red blood cell transfusions in patients having cardiac surgery is strongly associated with both infection and ischemic postoperative morbidity, hospital stay, increased early and late mortality, and hospital costs. The majority of those transfusions, the ones used on a precautionary basis, may in fact have been responsible for a large number of patient deaths over the last hundred years.
That doesn't mean that transfusions should be avoided at all costs; it just means that they aren't as risk free as most people think. And there are alternatives that can eliminate some of the risks. For example, in the case of elective surgery you can store your own blood for use as a transfusion during surgery. Even better, some hospitals make use of autologus blood salvage, which can recover your blood that is lost during surgery, clean it up, and reinfuse it into your body -- virtually eliminating any need for a transfusion.
Whether it's a serious illness that isn't screened for such as babesiosis or a heart attack due to donor blood that's been sitting around too long, the problems associated with transfusions need to be accounted for. The bottom line is that transfusions should be a last resort except, in fact, when they are indeed the last resort.
1 Herwaldt, Barbara L.; Linden, Jeanne V.; Bosserman, Elizabeth; et al. "Transfusion-Associated Babesiosis in the United States: A Description of Cases." Annals of Internal Medicine. 5 September 2011. American College of Physicians. 13 October 2011. <http://www.annals.org/content/early/2011/09/02/0003-4819-155-8-201110180-00362.abstract?sid=9b853849-f368-40c0-b5e8-6dd7c0857bb7>.
2 Bennett-Guerrero, Elliott; Veldman, Tim H.; Doctor, Allan; et al. "Evolution of Adverse Changes in Stored RBCs." Proceedings of the National Academy of Sciences of the United States of America. 11 October 2007. National Academy of Sciences. 16 October 2011. <http://www.pnas.org/content/104/43/17063>.
3 Gorman Koch, Colleen; Li, Liang; Sessler, Daniel I.; et al. "Duration of Red-Cell Storage and Complications after Cardiac Surgery." The New England Journal of Medicine. 20 March 2008. NEJM.org. 16 October 2011. <http://www.nejm.org/doi/full/10.1056/NEJMoa070403#t=abstract>.