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| A child participating in a longitudinal cohort study of mosquito-borne illness in Managua, Nicaragua, submits an annual blood sample. In a new study, the research team reports that children who have antibodies to the Zika virus are more susceptible to getting sick with dengue. Photo: by Paolo Harris Paz |
Exciting news today for advocates of Intelligent [sic] design, from the University of California, Berkeley! Researchers there, led by Leah C. Katzelnick have discovered that people who have had the Zika Virus (ZIKV) and developed immunity to it, are more vulnerable to developing dengue disease later on. Dengue is caused by a viruses which are closely related to ZIKV.
This finding came from examining two cohorts of Nicaraguan children who lived through the Zikavirus epidemic of 2016 and a dengue epidemic of 2019. It conformed what had long been suspected - that some antibodies to ZIKV interact with the dengue virus to make the infection worse. The team's findings were published a couple of days ago in Science, regrettably behind a paywall. However, the Berkeley News article by Kara Manke has the details:
“The key thing that our study establishes is that prior Zika infection does significantly increase your risk of both symptomatic and more severe forms of dengue disease,” said study first author Leah Katzelnick, who performed the research as postdoctoral scholar at the University of California, Berkeley’s School of Public Health. “That finding raises the questions: Could a vaccine only targeted at Zika actually put people at increased risk of more severe dengue disease? And how can you design a Zika vaccine that only induces good antibodies that protect you against Zika, but doesn’t induce these other, potentially enhancing antibodies that are harmful against disease?”
A family of related viruses
Dengue disease is caused by not one but four closely related types of flaviviruses, each of which can strike with a slightly different set of symptoms and severity. Getting sick with one type of dengue virus can increase the likelihood that a person will develop a second, more severe illness when infected with a separate type of dengue virus. However, after a person has been infected with two types of dengue viruses, they usually gain some degree of immune protection against future dengue disease severity.
[...]
When Zika first emerged in Latin America in late 2015, many speculated whether the flavivirus, a close cousin to the dengue viruses, might interact with the dengue viruses in a similar way.
“The first question was, ‘How will prior dengue virus infection affect Zika?’ because everyone in Latin America, to some degree or another, is eventually dengue immune and has dengue antibodies,” said study senior author Eva Harris, a professor of infectious diseases and vaccinology at UC Berkeley.
Since 2004, Harris and her colleagues in Nicaragua have monitored a cohort of approximately 3,800 children living in Managua, the country’s capital, tracking any signs of dengue disease and collecting annual blood samples to test for the virus and its antibodies. When chikungunya, another mosquito-borne virus, and Zika appeared in Nicaragua in 2014 and 2016, respectively, the cohort was expanded to capture cases of these emerging pathogens.
[...]
The team gathered data from its pediatric cohort and from another study of children being treated at a nearby pediatric hospital. By mid-autumn, the researchers had enough evidence to prove that having a prior Zika infection made a person more likely to have a symptomatic dengue infection. And as cases mounted, they found that prior Zika infection can also enhance dengue disease severity.
The team drew on the pediatric cohort’s bank of blood samples going back to 2004 to investigate other patterns of disease. It found that people who had one dengue infection, followed by a Zika infection, remained at high risk of developing a second, more severe dengue infection. In addition, when a person had two sequential dengue infections, the type of dengue virus that caused the second infection impacted whether the person was protected or experienced enhanced dengue disease.
[...]
When immunity backfires
When we get sick, our bodies produce large proteins called antibodies to help our immune system fight the infection. These antibodies have specific chemical shapes that allow them to stick to the pathogen of concern, flagging the invader to be broken down by immune cells. For viruses like Zika and dengue, they also can coat the virus and prevent it from entering the body’s cells, effectively neutralizing it.
Antibody-dependent enhancement can happen when an antibody designed to stick to one virus, like Zika, tries to stick to a slightly different virus, like dengue. Antibodies to Zika virus can attach to dengue viruses, but not quite well enough to neutralize them. As a result, when a passing immune cell senses the antibody “flag” and tries to break down the dengue virus, it can actually end up getting infected by the virus.
“This mechanism not only allows the virus to get into more cells to infect, but also suppresses the immune response of those cells, enabling the virus to produce even more virus,” Katzelnick said. “And, because they’re immune cells, they are moving around the body. And so, they can initiate a larger infection.”
This makes developing an effective vaccine against ZIKV much more complicated because dengue is much worse than the relatively mild Zikavirus which, unless it affects pregnant women when it can cause severe fetal brain under-development, is little more that a minor illness. However, it also means that in areas of the world where the ZIKV and the dengue viruses are endemic, ZIKV can sneak in and make the victim more susceptible to dengue.
ID advocates must attribute this to the intent of their putative intelligent [sic] designer, of course, since nothing it designs can have unexpected consequences and must be regarded as intelligently designed to do exactly what it does. As the work of a malevolent intelligence, this method of using one virus to act a bit like a Trojan horse to soften the victim up for another is sheer brilliance. It also neatly makes it much more difficult for human medical science to fight it, of course.
You can understand why creationists so admire the creative genius of this putative designer; what is difficult to understand though is why they imagine it to be a benevolent, loving deity with this evidence of it's sheer malevolent nastiness. But that's the cul-de-sac ID forces it's credulous advocates into, rather than go against the dogma and attribute things like this to an amoral, undirected, and unemotional natural process like evolution by natural selection.
This, and multiple examples of how any putative intelligent designer can only be honestly regarded as malevolent, will be in my forthcoming book, "The Malevolent Designer: Why Nature's God is not Good", the sequel to my popular, "The Unintelligent Designer: Refuting the Intelligent Design Hoax", which I'm pleased to see has been included in The Cure-For-Christianity Library.
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