Polio was one of the most feared diseases of the early 1950s, and its resurgence was especially troubling. In a recent 800-page medical review he read in preparation for recertification, he found that “polio is barely mentioned. Because our impression is that it’s almost eradicated.”
That’s how the virus disappeared this summer, as new outbreaks became a source of deepening anxiety and even alarm.
“Anything that’s been said before about we somehow defeat infectious diseases through treatment and prevention hasn’t really materialized,” said Jeremy Green, a professor of medical history at the Johns Hopkins University School of Medicine. “Concerning covid-19 as a once-in-a-lifetime, historic pandemic, the concern itself is a wishful statement…. Many in the infectious disease community are already anticipating some ‘next’.”
In many ways, virus intrusions are not accidental. Warming temperatures, forest loss and global travel have accelerated the spread of pathogens from animals to humans and between people in different parts of the world.
Over the past 50 years, the population has doubled to nearly 8 billion, driving the expansion of megacities and demand for land to build houses, grow crops and animals. According to the United Nations, global land transformation is causing the loss of nearly 25 million acres of forest each year, eroding traditional boundaries between the human and animal worlds.
Closer contact with animals puts us within reach of the pathogens they carry, which are responsible for 60% of human disease.
“We live in a world of microbial evolution, and microbes are taking advantage of every advantage they can get,” said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
On a deeper level, some experts believe, we’ve demonstrated a fundamental misunderstanding of where humans and microbes are on Earth. Viruses were around long before we were around, and far outnumbered us. Linking all the viruses end-to-end, “they would stretch 100 million light-years,” according to an editorial in Nature Reviews Microbiology.
German virologist Karin Morin put it this way: “We are invaders in the world of viruses, and vice versa.”
The summer of 2022 will likely drop as humans begin to understand the situation. Infectious diseases are big news.
“In the past, if you had reported one outbreak out of a hundred or so outbreaks in Africa at any one time, it would have been remarkable. But now, more people are being reported,” said Infectious Diseases, London School of Hygiene and Tropical Medicine. said Jimmy Whitworth, a physician specializing in epidemiology and public health.
Western health authorities and the media paid little attention to the monkeypox outbreak in Nigeria in 2017, although they became more active in finding harmful microbes in soil and sewage.
“One of the things that’s happening with our increasing focus on infectious diseases is that we’re now looking at various diseases in wastewater, including polio,” said Stephen Keesler, a postdoctoral fellow in the Department of Immunology. Infectious Diseases at Harvard TH Chan School of Public Health. “We were able to detect it in places we might not have noticed before.”
Keesler said he thinks the high levels of virus activity this summer are “partly just bad luck, just as a bad storm is partly bad luck. But unfortunately at the top of this trend, we can start to get more Expect these events more and more often.”
The most frequently cited trend by scientists is the powerful impact of human behavior on the planet. According to the United Nations, a major turning point occurred in 2009, when the population of cities overtook rural areas for the first time.
The increase in urban dwellers has led to overburdened and polluted water and sanitation systems, especially in poorer countries. The situation set the stage for the spread of waterborne diseases such as cholera, which infected more than 820,000 people and killed nearly 10,000 in Haiti after the 2010 earthquake. While cholera is caused by bacteria, water can also transmit viruses, including hepatitis A and E, rotavirus, norovirus, and poliovirus.
Climate change also increases the risk of infectious diseases. Writing last month in the journal Nature Climate Change, the researchers reported that 58 percent of the 375 infectious diseases they examined were “exacerbated at some point by climate disasters.” Only 16% of diseases are sometimes reduced due to climate change.
While climate brings humans closer to animals, warmer temperatures are attracting insects and other carriers Diseases in parts of the world that were once too cold to survive.
Whitworth said the Asian tiger mosquito is “moving steadily north” to spread diseases such as chikungunya, Zika and dengue into the New World, as a prime example. This mosquito, officially known as Aedes albopictus, was once found mainly in tropical forests in Southeast Asia. But over the past 50 years, it has spread to Europe, the Middle East, Africa, and North and South America. Mosquitoes first appeared in tire dumps in Harris County, Texas, in the mid-1980s.; it Progress has since been made in much of the country.
The international trade in the 1 billion scrap tires generated each year supports much of the tiger mosquito migration. Old tires can collect water, making them an ideal breeding ground for mosquitoes.
The summer’s virus activity is the result of trends that have developed over the past decade, said Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine.
“I think it’s a confluence of climate change, global warming, changing rainfall patterns — but not just climate change,” he said. “I think it’s consistent with … wars and political collapse, socioeconomic decline — because poverty is the main driver — radical urbanization, deforestation and anti-vaccine activists and what I call anti-scientific aggression.”
Gonzalo Moratorio, head of the Laboratory for Experimental Evolution of Viruses at the Pasteur Institute in Montevideo, Uruguay, called these factors, along with human travel and reliance on meat, “an explosive mixture, The opportunity that led to these epidemics. It’s been witnessing.”
Although 83% of Uruguay Even though vaccination rates against covid-19 surpass the US (68%) and the UK (75%), there is still a strong backlash against injections. Moratorio said his house had been painted with anti-vaccine graffiti after being attacked in the street by a stick-wielding vaccine opponent a year ago.
Part of the problem, he said, is that “the vaccines are doing so well, and the success of this work is that some people don’t know these infections exist because they’re close to eradication.”
Eliminating infectious diseases is no easy task. The World Health Organization launched efforts to eradicate smallpox in 1959, and finally declared victory on May 8, 1980, the only successful eliminate A human infectious disease.Similar efforts to end polio have taken more than 30 years and cost $17 billion.
Efforts to eradicate polio will be “more difficult to do, given the recent travel to Poland and Hungary of an unvaccinated Rockland County man this summer to be diagnosed with polio and the detection of the virus in the sewage systems of two major cities.” Many,” Keesler said. “With infectious diseases, there’s a huge difference between no infection and a little bit of infection.”
As long as covid-19 persists and other viral threats loom, world health leaders will not have the luxury of focusing on polio.
Measures taken to fight covid-19 – shutdown, Social distancing and wearing masks – can lead to far lower than average deaths from more common viruses like the flu. However, as people relax those protections, the virus is returning to communities where immunity is now low.
“I think that’s a good explanation for what we’re seeing with hepatitis,” said Dean Bloomberg, director of the UC Davis Division of Infectious Diseases, of this year’s global outbreak. “There was little transmission during… Shut down, there is a repressed sensitivity as things go. “
Another virus he expressed concern was the paracholecystovirus circulating in the United States. At least from spring. The virus can cause fever, encephalitis-like syndrome, and severe sepsis in newborns and young children.
Bloomberg’s biggest concern, however, is measles, which he describes as “one of the most contagious pathogens known to man.” Measles can be serious, even fatal, in small children.
“Even small declines in population immunity can lead to widespread transmission,” He says. “So we went through this decline, we increased travel as travel restrictions eased. Most of the travel will be to areas of the world with higher measles transmission rates. I think it’s only a matter of time before the U.S. imports more measles.”
In Uruguay, Moratorio said he suspects the next threat may come from Mayaro virus, a dengue-like disease carried by mosquitoes native to tropical forests in South America, “with the potential to become the new Zika Virus”.He said he hoped people would learn from it The pandemic and additional virus activity this summer, “but I’m not sure policymakers have gotten the hang of it. All of a sudden, markets and inflation are important things.”
Researchers say fighting Infectious diseases must be a global priority – countries also see outbreaks in another country as their problem. They stressed that rich countries must share vaccine doses with poorer countries to curb the spread of the virus before they can travel around the world.
Given the potential “economic collapse” of the pandemic, U.S. leaders must take the threat of pandemics as seriously as they do terrorism, nuclear weapons and cyberattacks, Hotez said. “We know from studies of bat ecology in Asia and elsewhere that this is just the beginning,” he said. “We’re going to roll out covid-25 and covid-31.”
At Montefiore Nyack Hospital, Azfar Chak said he, his wife and their four children were all fully vaccinated against the coronavirus. While he added that “some outbreaks are inevitable, he remains hopeful that “we will return to pre-pandemic normalcy”.
Experience taught him to expect surprises.A few years ago, he and his colleagues dealt with measles Outbreak that sickened 312 people People in Rockland County, most of them unvaccinated children — long after the World Health Organization declared the U.S. to eliminate endemic transmission of the virus.
The WHO warned in a 2000 statement: “Measles continues to be brought into the United States by travelers, where it sometimes spreads and causes outbreaks in unvaccinated populations.”