Thursday, October 1, 2015
Old Blood and New Science
Fig.1. This Asian tiger mosquito (Aedes albopicts) can carry dangerous emerging diseases (Credit: James Gathany, CDC)
Little over a year ago, the first locally acquired case of the mosquito-borne disease chikungunya appeared in the continental United States. This virus had only been recognized seven months prior in the Western Hemisphere, but quickly joined diseases such as Ebola and hantavirus on the ever-growing list of emerging infectious diseases.
The arrival of chikungunya and a second mosquito-borne disease called dengue fever in the United States has worried blood bank officials, who must constantly address new types of infections in blood samples. These diseases can live in the bloodstream for weeks before showing symptoms, creating a challenge for screening and identification.
To understand how viruses hide in human blood, virologist Amit Kapoor at Columbia University and an international team of scientists combed through blood samples from the 1970s and 1980s. Such samples would not have been subjected to the same rigorous screening methods as today, which operate to remove contaminated or diseased blood from the donation pool. The scientists scoured the pretransfusion and posttransfusion vials for small fragments of RNA and compared them to known virus sequences. What they found was surprising: a novel virus was present in two out of 46 posttransfusion samples. Although the rest of the samples were clean, a separate examination of 106 hemophiliac patient blood samples revealed two more instances of the virus.
This mysterious new virus, named human hepegivirus 1 (HHpgV-1), is closely related to the dangerous hepatitis C virus and the harmless human pegivirus, leaving the researchers confused as to its function in the human body. Their results, published last week in the journal mBio, stress that it is too early to draw conclusions about how the virus operates and whether or not is is a threat to humans.
Kapoor et al.’s study highlights the obvious need to return to older samples as techniques improve. Molecular technologies advance quickly and these “deep sequencing” analyses allow scientists to catch a disease before it appears in symptoms. Unfortunately, such methods are often expensive and time consuming, prompting groups like the Suncoast Blood Bank in Florida to invest in products that remove pathogens from blood platelets. This technology, provided by a biomedical company called Cerus Corporation, uses light to deactivate deadly pathogens in samples. Again, banks do not always have the funds to cover such costs, but a spike in dangerous viruses in donated blood spurred officials into action.
New regulation is underway in the United States to address contamination in blood samples, which threatens the 41,000 daily blood donations needed by patients in the country. Nevertheless, scientists and blood bank officials must be aware of the ongoing danger caused by emerging infectious diseases. Hopefully through concerted efforts like those in Florida and with Kapoor’s team, the country’s blood supply will remain safe.
Cohen, J. (2015). New human virus discovered in old blood samples. Science. Retrieved from http://news.sciencemag.org/biology/2015/09/new-human-virus-discovered-old-blood-samples
Goedert, J. J., Brown, D. L., Hoots, K., & Sherman, K. E. (2004). Human immunodeficiency and hepatitis virus infections and their associated conditions and treatments among people with haemophilia. Haemophilia, vol. 10 (s4): 205-210. doi: 10.1111/j.1365-2516.2004.0097.x
Kapoor, A., et al. (2015). Virome analysis of transfusion recipients reveals a novel human virus that shares genomic features with hepaciviruses and pegiviruses. mBio, vol. 6 (5): e01466-15. doi: 10.1128/mBio.01466-15
Landro, L. (2015, September 27). The rising risk of a contaminated blood supply. The Wall Street Journal. Retrieved from http://www.wsj.com/articles/the-rising-risk-of-a-contaminated-blood-supply-1443407428