After corona, G4 virus may go viral?
Chinese researchers have discovered a new type of swine flu that can infect humans and has the potential to cause a future pandemic, according to a study released recently, though scientists have cautioned that the virus does not pose an immediate global health threat. The disease, which researchers called the G4 virus, is genetically descended from the H1N1 swine flu that caused a pandemic in 2009. G4 now shows “all the essential hallmarks of a candidate pandemic virus,” said the study, published in the scientific journal ‘Proceedings of the National Academy of Sciences’ (PNAS).
In 2009, the H1N1 swine flu pandemic killed an estimated 151,700 to 575,400 people globally. In the aftermath, authorities and scientists stepped up surveillance of pig populations to watch for viruses with “pandemic potential”. After 2009, the H1N1 virus in humans spread back into pigs around the world, and the genes mixed into new combinations creating new viruses like G4. “Pig farming is a massive industry in China and pigs can be important hosts from which novel influenza viruses may emerge,” said James Wood, Head of Veterinary Medicine at the University of Cambridge. He added that the study was a “salutary reminder that we are constantly at risk of new emergence of zoonotic pathogens and that farmed animals, with which humans have greater contact than with wildlife, may act as the source for important pandemic viruses”. To decrease the risk of a human pandemic, Chinese farmers and authorities need to control the spread of the virus among pigs, and closely monitor people who work with the animals, said the team. The new study comes as the world grapples with the Covid-19 pandemic, which has now infected more than 10.3 million people globally and caused more than 505,000 deaths, according to data from Johns Hopkins University.
But Dr. Angela Rasmussen, a virologist at Columbia University's public health school, warned the public not to press the panic button. “Our understanding of what is a potential pandemic influenza strain is limited,” she posted on Twitter. “Sure, this virus meets a lot of the basic criteria but it's not for sure going to cause a hypothetical 2020 flu pandemic, or even be a dominant strain in humans.” Chinese researchers based at several institutions, including Shandong Agricultural University and the Chinese National Influenza Center, discovered the G4 virus during a pig surveillance program. From 2011 to 2018, they collected more than 30,000 nasal swab samples from pigs in slaughterhouses and veterinary teaching hospitals across 10 Chinese provinces. From these samples, researchers identified 179 swine influenza viruses – but not all of them posed a concern. But the G4 virus kept showing up in pigs, year after year, and even showed sharp increases in the swine population after 2016. Further tests showed that G4 can infect humans by binding to our cells and receptors, and it can replicate quickly inside our airway cells. And though G4 holds H1N1 genes, people who have received seasonal flu vaccines won’t have any immunity. G4 already appears to have infected humans in China. In Hebei and Shandong provinces, both places with high pig numbers, more than 10% of swine workers on pig farms and 4.4% of the general population tested positive in a survey from 2016 to 2018.
There is no evidence yet that G4 could spread from person to person— perhaps the most promising sign so far, said Carl Bergstrom, a professor of biology at the University of Washington. “This is not a new virus; it’s been very common in pigs since 2016,” he tweeted. “There's no evidence that G4 is circulating in humans, despite five years of extensive exposure. That's the key context to keep in mind.” However, researchers warn in the paper that the virus was on the rise among pig populations, and could “pose a serious threat to human health” if not carefully monitored. Transmission of the virus from pig to human could “lead to severe infection and even death,” said the study, which called for greater control of the virus’ spread within pig populations.
Gold mining ‘ails’ tropical forests
Gold mining significantly limits the regrowth of Amazon forests, greatly reducing their ability to accumulate carbon, according to a new study. The researchers warn that the impacts of mining on tropical forests are long-lasting and that active land management and restoration will be necessary to recover tropical forests on previously mined lands.
Gold mining has rapidly increased across the Amazon in recent years, especially along the Guiana Shield, where it is responsible for as much as 90% of total deforestation. The Shield encompasses Guyana, Suriname, French Guiana, Venezuela and small parts of Colombia and northern Brazil, and its forests hold roughly twenty billion tonnes of aboveground carbon in its trees. The ability of tropical forests to recover from gold mining activities has remained largely unquantified. Now, an international study led by the University of Leeds is the first to provide detailed field-based information on the regeneration of forests in Guyana after gold mining, and the first ground-based estimate of carbon sink lost as a result of gold mining activities across the Amazon.
The team’s findings, published in the Journal of Applied Ecology, found that forest recovery rates on abandoned mining pits and tailing ponds are amongst the lowest ever recorded for tropical forests. At some sites there was nearly no tree regeneration even after three to four years since mining had stopped. They estimate that mining-related deforestation results in the annual loss of over two million tons of forest carbon across the Amazon. The lack of forest regrowth observed following mining suggests that this lost carbon cannot be recovered through natural regeneration. Lead author Dr Michelle Kalamandeen, began this research as a postgraduate researcher in the School of Geography at Leeds. She is now a post-doctoral researcher at Cambridge University. She says: “This study shows that tropical forests are strongly impacted by mining activities, and have very little capacity to re-establish themselves following mining. Our results clearly show the extraction process has stripped nitrogen from the soil, a critical component to forest recovery, and in many cases directly contributed to the presence of mercury within neighbouring forests and rivers. Active mining sites had on average 250 times more mercury concentrations than abandoned sites. Not only does this have serious consequences for our battle against global warming by limiting Amazonian forests’ ability to capture and store carbon, but there is also a larger implication of contaminating food sources especially for indigenous and local communities who rely on rivers.”
A positive finding from this study shows that overburden sites, areas where topsoil is deposited during the mining process, recorded similar recovery rates as other Central and South American secondary tropical forests abandoned after agriculture or pasture. Active management and enforcement of laws is clearly needed to ensure recovery and to safeguard communities and there are methods available, such as replacing the soil using the overburdens at abandoned sites. But there is an urgent need for large-scale recovery management to be tested and implemented. “We could be facing a race against the clock. The current crisis is significantly increasing the demand for gold, given its perceived role as an economic stabiliser. With current gold price more than US$1700 per ounce and estimated to reach US$2000-3000 in the coming months, many artisanal and small-scale miners are already rapidly responding to this increase in pricing, and the weakening of environmental laws and policies as we've seen in Brazil, leading to further deforestation in the Amazon,” she says.