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Top 5 Contagion® News Articles for the Week of April 23, 2017


#3: Phylogenetically Mapping the Evolution of the Zika Virus as It Spread Across the World 

Using Nvector, a suite of tools that solve geographical positioning, Contagion® Editorial Advisory Board member and PhD candidate, Adriano de Bernardi Schneider, MS, and his research team started tracking the genetics of the Zika virus’ spread across the world in the first months of 2016. The team was able to “phylogenetically demonstrate that the viral sequences obtained from Zika as it crossed the Pacific Ocean (and subsequently radiated across northern Latin America and the Caribbean) were unlikely to be derived from the African strain of the virus, which was first described in 1947.” In fact, “the sequences from Brazilian and Pacific Island Zika isolates clearly clustered as a different strain, or clade, and were found to be more closely related to the historic Asian rather than the historic African isolates.”
In addition, the team utilized their computational modeling tools to shed some light on why the virus was causing birth defects in infants and Guillain-Barré syndrome (GBS) in adults. With the help of additional researchers, the team “identified a set of mutated viral sequences encoding predicted epitopes with homology to epitopes predicted for human neural development-related proteins: NDF4 (Neurogenic differentiation factor 4) and Nav2 (Neural navigator protein 2). Based on this observation, we raised the hypothesis that epitope mimicry may contribute to both congenital Zika syndrome as well as GBS.” One characteristic of epitope mimicry is an autoimmune response in the affected host. This “clinical autoimmunity can occur when virus proteins are similar to human proteins.”
Continue reading more about the teams findings about the Zika virus here

#2: Researchers Identify Zika Incubation Period and Optimal Testing Methods 

Although the majority of Zika virus infections in the United States have historically been travel-related, the approaching warmer months will bring with them mosquitoes and thus renewed fears of locally-acquired infections. Researchers may have now discovered a better way to determine whether a case of Zika virus was truly acquired locally, or if it came in through travel to a Zika-endemic region.
Indeed, a new analysis from the Centers for Disease Control and Prevention (CDC) has provided more information on the differences seen in locally-acquired vs travel-related cases. For example, the researchers “found that among symptomatic Zika-infected travelers, 99% experience symptoms within 2 weeks of exposure, and 50% within 1 week.” Therefore, the researchers recommended that those individuals who develop Zika-associated symptoms “more than 2 weeks after travel to a Zika-endemic area ‘should be evaluated for alternative modes of transmission.’” It is this aspect—evaluating individuals for alternative modes of transmission—that is key to helping epidemiologists identify locally-acquired cases sooner, and aiding in more rapid implementation of vector-control strategies. In addition, the results of the study suggested that “the incubation period for the Zika virus is between 3 and 14 days.”
In a related study, researchers have found evidence to support the use of whole blood over plasma samples for the molecular diagnosis of acute symptomatic and asymptomatic Zika virus infections as “the use of whole-blood specimens is much more sensitive than the use of plasma samples to detect Zika virus RNA.” In addition, the data from the study could be useful for analyzing “the safety of whole blood and blood components from donors, as well as for the safety of organs, tissues, and cells from deceased and living donors.”
More information on the incubation period of and optimal testing methods for the Zika virus is available here.

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