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DENV in endemic regions spreading through blood transfusions
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Transmissions of dengue virus through blood transfusions may be ongoing in endemic regions of the world during epidemic periods, according to recent findings.
“This is the largest study of [transfusion transmission (TT)] dengue to date,” researchers wrote in The Journal of Infectious Diseases. “Our findings confirm that during seasonal epidemics substantial proportions of asymptomatic donors with infection are donating blood and recipients are receiving RNA-positive blood components.”
In the linked donor-recipient study, Brian S. Custer, PhD, MPH, senior investigator at the Blood Systems Research Institute in San Francisco, and colleagues evaluated 39,134 blood donors recruited from Brazilian blood centers at a general hospital and a cardiovascular hospital. From February to June 2012, the researchers collected extra plasma from each donor and identified the recipients of the blood daily. Recipients gave blood samples between 3 and 21 days after transfusion, and pretransfusion recipient blood also was retrieved and frozen. Transcription-mediated amplification was used to retrospectively test the samples for dengue virus (DENV). Chart reviews were conducted to evaluate patient symptoms. Recipients were classified as cases or controls, based on RNA positivity for DENV or if they had received transfusions from donors positive for DENV RNA.
Brian S. Custer
Custer and colleagues found that DENV-4 viremia was detected in 0.51% of the donor samples from Rio de Janeiro and 0.8% of those from Recife. There were 6,536 blood components transfused to 657 enrolled recipients from whom a post-transfusion sample could be obtained. Of these, 0.64% donation units transfused to 34 recipients were DENV RNA-positive.
Sixteen of the RNA-positive units transfused to 16 recipients were valid for estimating the TT rate. Ten cases were considered nontransmissions, five were probable TT, and one was possible TT. An estimated TT rate of 37.5% (95% CI, 15.2%-64.6%) was determined, and this rate was greater than the 0.93% (95% CI, 0.11%-3.34%) viremia rate in nonexposed recipients (P < .0001). The chart review revealed no significant differences in symptoms or mortality between cases vs. controls.
According to the researchers, during peak epidemic periods, roughly 1% to 2% of blood donations may be RNA-positive for dengue.
“During seasonal epidemics in dengue-endemic countries, substantial proportions of infected, asymptomatic donors are giving blood,” Custer told Infectious Disease News. “Transfusion-transmission of dengue virus is occurring, but screening donors to prevent transmission to recipients may have limited value and may not impact the burden of clinically apparent infection in blood recipients. Against the backdrop of the clinical status of each patient, resulting from the underlying medical condition or indication requiring blood transfusion, identifying serious overt complications directly attributable to dengue infection in blood recipients is difficult. However, these findings may not be applicable to low or non-endemic countries where larger proportions of patients may have never been previously exposed to Dengue.”
In a related editorial, José Eduardo Levi, PhD, of Hospital Israelita Albert Einstein, Sao Paulo, Brazil, described potential countermeasures to the spread of dengue through transfusion.
“Emerging and re-emerging viruses continue to threaten the blood supply,” Levi wrote. “Clearly, the current approach of ‘a new test for each new agent’ results in increasing the already high cost and complexity of blood screening. Two extremely promising alternatives for this dilemma are methods that would inactivate all virus nucleic acids in blood and unbiased sequencing of donor cell-free plasma nucleic acids, revealing the whole human genome in addition to the microbial diversity.” – by Jen Byrne
Disclosures: Custer reports no relevant financial disclosures. Levi reports a grant from Novartis (now Grifols) on the subject of dengue in blood donors. Please see the full study for a list of all other authors’ relevant financial disclosures.
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