Microbiology

Over recent weeks and months, we’ve heard of several COVID cases in which people have tested positive after previously clearing the virus. Scientists are hopeful being infected with COVID-19 confers immunity for a length of time. But some of these instances have raised concerns about reinfection. Although rare, it seems to be possible. The other thing which could be at play in many of these cases is “prolonged viral shedding”. Both phenomena are probably more common than we realise. But it’s important to understand the differences between the two. What is viral shedding? When you’re sick…

After originating in Wuhan, China in late 2019, the latest form of coronavirus, SARS-CoV-2, and its third pandemic of the last 17 years, has spread COVID-19 across the globe. Some countries claim fewer cases, like China, while some can't know figures, like Brazil, but one thing is clear; the half the world that interacts with China even indirectly has it, and it has mutated along the way. The California version which came from Asia is different than the New York version that came from Europe. Fortunately, none of the mutations have increased transmissibility, according to a new paper which…

While the world recovers from the third coronavirus pandemic of the last 17 years, it's important to be mindful that nature is always evolving new ways to kill. It's why scientists need to create a new influenza vaccine each year. The Next Plague is always just around the corner and researchers are looking for ways to head them off. Researchers at Washington University School of Medicine in St. Louis have identified a molecule that protects mice from brain infections caused by Venezuelan equine encephalitis virus (VEEV), a mosquito-borne virus notorious for causing fast-spreading, deadly…

Mumps IgG titers, levels of IgG antibody, have been correlated to lowered severity in recovered COVID-19 patients who had the Merck MMR II vaccine, and that has led a group to speculate that the MMR vaccine may protect against COVID-19. That sounds great but the problem with correlation is that while it sounds scientific, it can still just be statistical association and prone to wishful thinking. Groups like International Agency for Research on Cancer (IARC) in France have claimed using statistics that weedkillers and meat might cause cancer, but when it was revealed insiders guiding those…

A new study found that natural selection, a key mechanism in biological evolution, favors pathogens with more virulence - how much harm they cause - at the point the disease emerges in a new host species. Not too much, or else everything will be dead, but not too weak to matter either.  Virulence and transmission are linked, with virulence arising because pathogens need to exploit hosts to persist, replicate and transmit. Low virulence will be detrimental for pathogens if they cannot transmit while virulence that is too high will also be a disadvantage if infection kills hosts so fast…

To estimate infection rates of viruses like SARS-CoV-2, immunologists use a basic reproduction number, known as R0 (pronounced “R naught”) - an expression of the number of people likely to catch a disease from one contagious person - and a Susceptible-Infected-Removed (SIR) model. Yet as we have seen, those are only telling part of the science story. Coronavirus is in the same family as the common cold and for many COVID-19 will be just like the cold, and can spread like the cold. But when it comes to successful transmission, viruses only win they can optimize their aptitude to survive and…

Between 6 and 8 million people worldwide suffer from inflammatory bowel disease, a group of chronic intestinal disorders that can cause belly pain, urgent and frequent bowel movements, bloody stools and weight loss. New research suggests that a malfunctioning member of the patient’s own immune system called a killer T cell may be one of the culprits. This discovery may provide a new target for IBD medicines. The two main types of IBD are ulcerative colitis, which mainly affects the colon, and Crohn’s disease, which can affect the entire digestive tract. Researchers currently believe that IBD…

An annotated list of 219 pathogens that infect plants in Brazil, including many agriculturally important species, shows just how precarious things can be when it comes to maintaining an affordable, sustainable food supply. Dr. Elliot Watanabe Kitajima, a researcher in the Phytopathology and Nematology Department of the University of São Paulo’s Luiz de Queiroz College of Agriculture, has been collecting publications on plant viruses in Brazil for decades and has recorded over 8,000 references to date. That led to the new Biota Neotropica article which presents descriptions of the…

We eat various foods and our metabolism converts it to energy our bodies can use. This is a hallmark of life, across plants, animals, algae and bacteria. Energy is a defining characteristic of living. But how little can an organism really live on? In the extreme environment of the seabed, answers may be found. New research finds that an entire biosphere of microorganisms - as many cells as are found in all the Earth's soils or oceans - has barely enough energy to survive. A few zeptowatts (~1×10−21.)  But they do survive, for millennia. Many of them exist in a mostly inactive state…

Biologists have mapped the genome of phylloxera, an aphid-like pest capable of decimating vineyards. In so doing, they have identified nearly 3,000 genes enabling the insect to colonize and feed on grape vines by creating what are essentially nutritionally enhanced tumors. The tumor-like structures, known as galls, disrupt the vine's ability to move nutrients and feed itself. They also create wounds in roots that make grapevines more susceptible to fungi and other pathogens, ultimately killing the vines. But they have co-evolved all this time because when they feed on plants and start…