April 30, 2016

There are yet new reasons to avoid mosquito bites… and to eliminate mosquito breeding sites. We’ve written extensive articles on this where you can find lots of critical details … see  Continue reading Chikungunya & Dengue Virus Information →   and  Continue reading Dengue Fact Sheet →

Now Zika brings new risks.
Dengue infections cause human immune systems to create a special kind of antibodies, called sub-neutralizing antibodies, that persist in our bodies for the rest of our lives … These Dengue virus induced sub-neutralizing antibodies cause every future Dengue infection to cause the patient worse, and worse symptoms, sometimes ending with Dengue Hemorhaggic Fever and possibly death.

In short, the most recent high quality lab studies show that anti-DENV HMAbs, cross-react, DO NOT NEUTRALIZE, and …instead … greatly enhance ZIKV infections … in vitro.

Generally, we paraphrase important scientific articles, but I believe that this article explains itself:

http://biorxiv.org/content/early/2016/04/25/050112

“For decades, human infections with Zika virus (ZIKV), a mosquito-transmitted flavivirus, were sporadic, associated with mild disease, and went underreported since symptoms were similar to other acute febrile diseases endemic in the same regions. Recent reports of severe disease associated with ZIKV, including Guillain-Barre syndrome and severe fetal abnormalities, have greatly heightened awareness.

Given its recent history of rapid spread in immune naive populations, it is anticipated that ZIKV will continue to spread in the Americas and globally in regions where competent Aedes mosquito vectors are found. Globally, dengue virus (DENV) is the most common mosquito-transmitted human flavivirus and is both well-established and the source of outbreaks in areas of recent ZIKV introduction.

DENV and ZIKV are closely related, resulting in substantial antigenic overlap. Through a mechanism known as antibody-dependent enhancement (ADE), anti-DENV antibodies can enhance the infectivity of DENV for certain classes of immune cells, causing increased viral production that correlates with severe disease outcomes.

Similarly, ZIKV has been shown to undergo ADE in response to antibodies generated by other flaviviruses. However, response to DENV antibodies has not yet been investigated.

Methodology / Principal Findings
We tested the neutralizing and enhancing potential of well-characterized broadly neutralizing human anti-DENV monoclonal antibodies (HMAbs) and human DENV immune sera against ZIKV using neutralization and ADE assays.

We show that anti-DENV HMAbs, cross-react, do not neutralize, and greatly enhance ZIKV infection in vitro.

DENV immune sera had varying degrees of neutralization against ZIKV and similarly enhanced ZIKV infection. Conclusions / Significance Our results suggest that pre-existing DENV immunity will enhance ZIKV infection in vivo and may increase disease severity.

A clear understanding of the interplay between ZIKV and DENV will be critical in informing public health responses in regions where these viruses co-circulate and will be particularly valuable for ZIKV and DENV vaccine design and implementation strategies. ”

Continue reading to find out how to STOP Dengue,  Chikungunya,  and Zika viruses … and protect yourself  and loved ones… at    Continue reading Dengue Fact Sheet →

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© Steven M. Fry

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