Nav: Home

Newly emerged enterovirus-A71 C4 isolates may be more virulent than B5 in northern Vietnam

April 09, 2020

Kanazawa, Japan - Hand-foot-and-mouth disease (HFMD) is an acute viral infection that usually affects infants and children below five years. In a study published in Scientific Reports in January 2020, an international research team including Kanazawa University, the Vietnam National Hospital of Pediatrics, Tokyo Metropolitan Institute of Medical Science, Nagasaki University and Hanoi Medical University, has demonstrated the emergence of a new enterovirus (EV) A71-C4 lineage during the 2015-2016 outbreak of HFMD in northern Vietnam. Further, through clinical studies and an experimental mouse model, they have shown that EV-A71 C4 subgenotype may be more virulent than the B5 subgenotype.

HFMD is a common contagious childhood illness caused by enteroviruses of the family picornaviridae, the most frequently reported being EV-A71, coxsackievirus A16 (CV-A16), and CV-A6. It typically runs a mild self-limiting course; however, in rare cases it may cause inflammation of the meninges and the hindbrain, resulting in paralysis, cardiopulmonary complications, or even death. While most cases resolve within a few weeks, EV-A71 infections may be more severe, with serious complications.

To determine the epidemiological characteristics and identify the various enterovirus strains responsible for HFMD in northern Vietnam, the research team collected and analyzed throat and rectal swabs from 488 affected children in Hanoi.

Son T. Chu, lead author of the study, explains: "CV-A6 was the most common strain, followed by EV-A71. Of these EV-A71, 92.1% were the B5 subgenotype and 7.9% were the C4 subgenotype. Whole-genome sequencing showed that seven of the eight C4a strains formed a new lineage, including two possible recombinants between EV-A71-C4 and CV-A8 strains."

The researchers evaluated the proportion of inpatients as a clinical measure of virulence. Hospitalized children with EV-A71 significantly outnumbered those with CV-A6. Further analysis among the EV-A71 infected children showed that the proportion of inpatients among C4-infected was significantly higher than that among B5-infected, implying greater virulence of C4 than B5.

"As the number of C4-infected patients was small, we applied another technique to compare virulence," says Kyousuke Kobayashi, neurovirologist and lead author. "We inoculated transgenic mice susceptible to EV-A71 infection with viral isolates and monitored them for limb weakness, acute flaccid paralysis, body weight and death. We found increased paralysis and significantly higher mortality among mice infected with C4 strains than those infected with B5 strains."

HFMD is an emerging public health problem with periodic large outbreaks in pediatric populations in East and Southeast Asia. Currently, there is no approved antiviral drug against EV-A71 and the best strategy to mitigate its impact is to develop appropriate vaccines. Though inactivated vaccines exist, more suitable candidate strains may be identified from among the newly emerged EV-A71-C4 strains for developing live attenuated vaccines.
-end-


Kanazawa University

Related Vaccines Articles:

Better vaccines are in our blood
Red blood cells don't just shuttle oxygen from our lungs to our organs: they also help the body fight off infections by capturing pathogens in the blood and presenting them to immune cells in the spleen.
Challenges in evaluating SARS-CoV-2 vaccines
With more than 140 SARS-CoV-2 vaccines in development, the race is on for a successful candidate to help prevent COVID-19.
Designing vaccines from artificial proteins
EPFL scientists have developed a new computational approach to create artificial proteins, which showed promising results in vivo as functional vaccines.
Misinformation on vaccines readily available online
Parents researching childhood vaccinations online are likely to encounter significant levels of negative information, researchers at the University of Otago, Wellington, have found.
Battle with the cancer: New avenues from childhood vaccines
A new research from the University of Helsinki showed for the first time how the pre-immunization acquired through common childhood vaccines can be used to enhance therapeutic cancer treatment.
Personalized cancer vaccines
The only therapeutic cancer vaccine available on the market has so far showed very limited efficacy in clinical trials.
Doubts raised about effectiveness of HPV vaccines
A new analysis of the clinical trials of HPV vaccines to prevent cervical cancer raises doubts about the vaccines' effectiveness.
Egg-based flu vaccines: Not all they're cracked up to be?
Flu season is underway in the Northern Hemisphere, sickening millions of people and in rare cases, causing hospitalization or death.
You're probably not allergic to vaccines
Five facts about allergies to vaccines, pulled together by two McMaster University physicians.
Micromotors deliver oral vaccines
Vaccines have saved millions of lives, but nobody likes getting a shot.
More Vaccines News and Vaccines Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.