Tag: Zika virus

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Persistent Infection could Explain Some Long COVID Cases

On By ModernMedia
Image by Fusion Medical on Unsplash

A persistent infection could explain why some people experience long COVID symptoms, according to a new study led by researchers at Brigham and Women’s Hospital. The team found evidence of persistent infection in 43% of participants with cardiopulmonary, musculoskeletal or neurologic symptoms of long COVID. The results are published in Clinical Microbiology and Infection.

“If we can identify a subset of people who have persistent viral symptoms because of a reservoir of virus in the body, we may be able to treat them with antivirals to alleviate their symptoms,” said lead author Zoe Swank, PhD, a postdoctoral research fellow in the Department of Pathology at Brigham and Women’s Hospital.

The study analysed 1569 blood samples collected from 706 people, including 392 participants from the National Institutes of Health-supported Researching COVID to Enhance Recovery (RECOVER) Initiative,  who had previously tested positive for a COVID infection. With a highly sensitive test they developed, researchers looked for whole and partial proteins from the SARS-CoV-2 virus. They also analysed data from the participants’ long COVID symptoms, using electronic medical chart information or surveys that were gathered at the same time as the blood samples were taken.

Compared to people who didn’t report long COVID symptoms, those who reported persisting symptoms many organ systems were approximately twice as likely to have SARS-CoV-2 proteins circulating in their blood. The research team was able to detect the spike protein and other components of the SARS-CoV-2 virus using Simoa, an ultrasensitive test for detecting single molecules. Commonly reported long COVID symptoms included fatigue, brain fog, muscle pain, joint pain, back pain, headache, sleep disturbance, loss of smell or taste, and gastrointestinal symptoms.

Specifically, 43% of those with long COVID symptoms affecting three major systems in the body, including cardiopulmonary, musculoskeletal, and neurologic systems, tested positive for viral proteins within 1 to 14 months of their positive COVID test. But only 21% of those who didn’t report any long COVID symptoms tested positive for the SARS-CoV-2 biomarkers in this same period.

It’s possible that a persistent infection explains some – but not all – of the long COVID sufferers’ symptoms. If this is the case, testing and treatment could aid in identifying patients who may benefit from treatments such as antiviral medications.

A Condition with More Than One Cause

One of the questions raised by the study is why more than half of patients with wide-ranging long COVID symptoms tested negative for persistent viral proteins.

“This finding suggests there is likely more than one cause of long COVID,” said David Walt, PhD, a professor of Pathology at Brigham and Women’s Hospital and Principal Investigator on the study. “For example, another possible cause of long-COVID symptoms could be that the virus harms the immune system, causing immune dysfunction to continue after the virus is cleared.”

To better understand whether an ongoing infection is behind some people’s long COVID symptoms, Swank, Walt and other researchers are currently conducting follow-up studies. They’re analyzing blood samples and symptom data in larger groups of patients, including people of wide age ranges and those with compromised immune symptoms. This way, they can also see if some people are more likely to have persistent virus in the body.

“There is still a lot that we don’t know about how this virus affects people,” said David C. Goff, MD, PhD, a senior scientific program director for the RECOVER Observational Consortium Steering Committee and director of the Division of Cardiovascular Sciences at the National Heart, Lung, and Blood Institute (NHLBI), part of NIH. “These types of studies are critical to help investigators better understand the mechanisms underlying long COVID – which will help bring us closer to identifying the right targets for treatment.”

Goff added that these results also support ongoing efforts to study antiviral treatments.  

The SARS-CoV-2 blood test developed by Brigham and Women’s researchers is also currently being used in a national study, called RECOVER-VITAL, that is testing whether an antiviral drug helps patients recover from long COVID. The RECOVER-VITAL trial will test the patients’ blood before and after treatment with an antiviral to see if treatment eliminates persistent viral proteins in the blood.

The idea that a virus can stay in the body and cause ongoing symptoms months after an infection isn’t unique to COVID. “Other viruses are associated with similar post-acute syndromes,” said Swank. She noted animal studies have found Ebola and Zika proteins in tissues post-infection, and these viruses have also been associated with post-infection illness.

Source: Brigham and Women’s Hospital

Categories : Diseases, Syndromes and ConditionsTags :

Study Finds Wastewater Monitoring can Work for Most Pathogens

On By ModernMedia
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Researchers in the American Journal of Epidemiology report that wastewater surveillance of diseases that infect humans should work in most cases. But more research is needed to apply the science for public health benefit, the research team concluded.

Led by epidemiologist David Larsen from Syracuse University, the team’s work published examined all peer-reviewed scientific articles of wastewater surveillance published through July 2020. The team identified a variety of pathogens that can be found in wastewater, including almost all infectious diseases that the World Health Organization has classified as a Public Health Emergency of International Concern (PHEIC) such as Ebola virus and Zika virus.

But despite this positive finding, few studies relate what is found in the wastewater to public health and the amount of disease that is circulating.

“Testing the wastewater is only one component of this powerful science,” said Dr Larsen, an associate professor of public health at Syracuse University. “Understanding the results and implications for public health is just as challenging. We need interdisciplinary teams working together to maximise the benefit of wastewater-based epidemiology.”

Wastewater-based epidemiology is the science of taking what is found in wastewater and using that information to understand population-level health trends. Most of the articles reviewed looked at what they could find in the wastewater and omitted the second step of relating the findings to other measures of population-level health, such as numbers of cases, test positivity, or hospitalisations.

Wastewater-based epidemiology of COVID has enjoyed substantial availability of clinical COVID data, and results from wastewater surveillance are more easily understood in terms of COVID transmission. However, the research team determined that more work is needed to be done for other pathogens, including monkeypox and polio, to increase the utility of wastewater surveillance to benefit public health.

Source: Syracuse University

Categories : Diseases, Syndromes and ConditionsTags :

Zika Can Mutate to Increase its Infectivity

On By ModernMedia
Mosquito, a malaria parasite vector
Photo by Егор Камелев on Unsplash

Researchers have found that Zika virus has the potential to mutate and increase its infectivity, potentially breaking through pre-existing immunity.

“The world should monitor the emergence of this Zika virus variant,” said LJI Professor Sujan Shresta, PhD, who co-led the La Jolla Institute for Immunology (LJI) study which is published in Cell Reports.

A mosquito-borne virus, symptoms of Zika infection are usually mild in adults. However, in a developing foetus, infection can cause birth defects such as microcephaly.

Zika virus and dengue virus occur together in a number of countries. Both viruses are a mosquito-borne flavivirus, sharing biological similarity:  similar enough that prior dengue exposure can offer immune protection against Zika.

“In areas where Zika is prevalent, a vast majority of people have already been exposed to dengue virus and have both T cells and antibodies that cross-react,” said Prof Shresta.

Unfortunately, both viruses share the trait of rapid mutation. “Dengue and Zika are RNA viruses, which means they can change their genome,” she further explained. “When there are so many mosquitoes and so many human hosts, these viruses are constantly moving back and forth and evolving.”

To study Zika’s fast-paced evolution, the researchers simulated infection cycles that repeatedly switched back and forth between mosquito cells and mice. This painted a picture of how Zika virus naturally evolves as it encounters more hosts.

The LJI team found that an easy change of a single amino acid allows the virus to make more copies of itself — and help infections take hold more easily. This mutation (called NS2B I39V/I39T mutation) boosts viral replication in both mice and mosquitoes – and also in human cells.

“This single mutation is sufficient to enhance Zika virus virulence,” commented study first author Jose Angel Regla-Nava, PhD. “A high replication rate in either a mosquito or human host could increase viral transmission or pathogenicity – and cause a new outbreak.”

Prof Shresta added, “The Zika variant that we identified had evolved to the point where the cross-protective immunity afforded by prior dengue infection was no longer effective in mice. Unfortunately for us, if this variant becomes prevalent, we may have the same issues in real life.”

To help prepare for this variant, Dr Shresta’s laboratory is already looking at ways to tailor Zika vaccines and treatments that counteract this dangerous mutation.

“We want to understand at what point in the viral life cycle this mutation makes a difference,” said Dr Shresta.

Source: La Jolla Institute for Immunology

Categories : VaccinesTags :

Promising Zika Vaccine Protects Foetus in Animal Trial

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Mosquito
Photo by Егор Камелев on Unsplash

US researchers have shown that a Zika virus vaccine candidate is effective at preventing the Zika virus passing from mother to foetus in preclinical animal studies, according to a new study published in npj Vaccines.

“The vaccine has been shown to be safe for non-pregnant humans, but of course we need to know if it is safe and effective for the people at greatest risk: pregnant women and their fetuses,” said first author In-Jeong Kim, PhD, a viral immunologist at Trudeau Institute. “Our proof-of-concept studies conducted at Trudeau and Texas Biomed show very promising results that the vaccine given before pregnancy will provide high levels of protection for mothers and babies.”

The 2015–2016 Zika outbreak in Brazil and other countries in the Americas caused a surge in miscarriages and a constellation of birth defects, called Congenital Zika Syndrome, including abnormally small heads and neuro-developmental disorders.

“It’s important to test vaccines before the next large outbreak, because there will be another,” said senior author Jean Patterson, PhD, a virologist at Texas Biomed. “Zika is part of a family of viruses known to go through cycles. These viruses tend to spread rapidly through naïve populations that have never been exposed to the virus before, then infections drop down for years because most people have been exposed. As more and more people are born, there is a new group of naïve individuals in which the virus can once again wreak havoc. We want to help break that cycle.”

The purified, inactivated Zika vaccine (ZPIV) candidate was been tested in non-pregnant animals, showing it effectively clears the virus from blood. In Phase 1 human trials, it has been shown to be safe and elicit a protective immune response.

However for ethical and safety reasons, it is not possible to test whether the vaccine protects women and their foetuses from both infection and severe malformations, so animal models are used as a substitute.

Researchers tested the vaccine in pregnant mice and marmosets, respectively. The mouse studies, led by Dr Kim and Marcia Blackman, PhD, a viral immunologist at Trudeau, showed the vaccine prevented around 80% of foetal malformations, and neutralising antibodies were detected in foetal blood samples eight days after infection.

“We were able to detect maternal antibodies in the fetus during pregnancy and the results suggest the antibodies play a critical role in protecting fetuses from Zika virus,” Dr Kim said.

Marmosets are more sensitive to Zika infection than other nonhuman primates; previous research showed foetuses were aborted within two weeks of maternal infection.

In this study, four marmosets were immunised with the ZPIV vaccine and then exposed to Zika virus after they became pregnant. Only 1 of 12 offspring tested positive for Zika virus, demonstrating more than 90% effectiveness.

“Because the animals became pregnant at different times, our study was able to show the vaccine confers protection for at least 18 months after vaccination, which is important for showing long-lasting immunity,” Dr Patterson said.

The researchers are already testing what happens when the vaccine is administered during pregnancy.

“These studies add evidence that the Zika vaccine WRAIR developed not only protects animals against Zika virus infection, but also the congenital defects that mimic what has been observed in people,” says Kayvon Modjarrad, MD, PhD, who leads the US Army Zika vaccine programme. “Together with the early phase clinical trials, we believe these data lend even more support that this vaccine platform is a viable approach for countering the persistent threat of Zika.”

Source: Texas Biomedical Research Institute