Earth Wise

A look at our changing environment.

You are here: Home / Archives for pathogens

pathogens

Rats and climate change

By Leave a Comment

Human activity has made rats one of the most prolific mammals on the planet. Our waste, buildings, and ships provide food, shelter, and transport.  In the United States alone, rats cost the country approximately $27 billion each year in damage to infrastructure, crops, and contaminated food supplies. Additionally, rats carry and spread over 50 zoonotic pathogens and parasites, impacting public health around the world.

Now, climate change is adding to the problem. According to a new study recently published in the journal Science Advances, urban rat populations are exploding as global temperatures rise.  The researchers found that Washington DC, San Francisco, Toronto, New York City, and Amsterdam had the greatest population increases.  In fact, over the past decade, rats increased by a whopping 390% in Washington DC, 300% in San Francisco, 186% in Toronto, and 162% in New York City.  The study, which examined data from 16 cities globally, found that 11 of them showed significant increases in rat numbers.

Only Tokyo, Louisville, and New Orleans bucked the trend with declining rat numbers.

According to the researchers, the best pest management strategies involve making the urban environment less rat-friendly as opposed to removing rodents that are already there.  An example would be putting trash in containers instead of bags on the street. 

There aren’t many perks to the changing climate – unless, of course, you’re a rat. 

**********

Web Links

Increasing rat numbers in cities are linked to climate warming, urbanization, and human population

‘Perfect rat storm’: urban rodent numbers soar as the climate heats, study finds

Photo, posted September 25, 2018, courtesy of Tim Felce via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Tick-Borne Pathogens In Canada | Earth Wise

By Leave a Comment

Measuring only three to five millimeters in size, tiny ticks are a big problem.  They are widely distributed in many parts of the world, especially in warm and humid climates.  Ticks are arachnids – not insects – meaning they’re more closely related to spiders than to flies or mosquitos.  They are external parasites that feast on the blood of birds, reptiles, amphibians, and mammals – including humans.

In the United States, ticks are responsible for spreading potentially life-threatening infectious diseases.  According to estimates from the Centers for Disease Control and Prevention, ticks infect more than 300,000 people with Lyme disease in the U.S. every year, and the numbers continue to rise.  Other common tick-borne diseases include anaplasmosis, babesiosis, Rocky Mountain Spotted Fever, and powassan encephalitis.

Ticks are becoming a problem in Canada as well.  According to a new study by researchers from McGill University and the University of Ottawa, tick-borne pathogens are on the rise in Central Canada – a region where ticks were never previously detected. 

In the study, the researchers collected ticks across Ontario and Quebec.  They found that five emerging pathogens were present across their study sites, including the pathogens that cause Lyme disease and babesiosis.  The researchers also found that pathogens can transmit in different ways.  Typically, pathogens are transmitted to a tick after feeding from the blood of an infected host, like a small mammal.  But the research team found evidence of pathogens that could be directly transmitted from adult female ticks to larval ticks.

According to the researchers, more comprehensive testing and tracking is needed to detect the spread and risks of tick-borne pathogens to humans and wildlife in Canada.

**********

Web Links

Tick-borne pathogens increasingly widespread in Central Canada

Photo, posted May 4, 2009, courtesy of Jerry Kirkhart via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Making Cotton More Sustainable | Earth Wise

By Leave a Comment

In the United States, cotton is a $7 billion annual crop grown in 17 states.  Cotton plants in the largest producing countries in the world – India, China, and the U.S. – are genetically very similar and, like other crops that lack diversity, can be at risk.

Cultivated cotton around the world has been bred to look and act very similar.  It is high yielding and easy to harvest using machines.  But it is also wildly unprepared to fight disease, drought, or insect-borne pathogens.

Researchers are looking beyond breeding for ways to combat the low genetic diversity of cultivated cotton.  There are new approaches that combine breeding with elements of genetic modification.  Most cotton in the U.S. has already been genetically modified to resist caterpillar pests.  But as new problems emerge, new solutions will be needed that may require complicated changes to the cotton genome.  Getting regulatory approval for a genetically modified crop is a long and expensive process.

However, ordinary genetic modification is not the only possibility.  Modern genetic sequencing technology can allow researchers to examine various wild cotton varieties and identify the genetic markers for desirable traits.  Once valuable genes in wild species have been identified, traditional plant breeding techniques could be used to produce cultivated cotton varieties that are more resistant to disease and drought.

Climate change is raising average global temperatures and some important cotton-producing regions such as the U.S. Southwest are becoming drier.  Researchers are hoping to produce cultivated cotton that can tolerate drought at the seedling stage.  The ultimate goal is to create more sustainable and genetically diverse cotton that can thrive in a changing world.

**********

Web Links

Cotton Breeders Are Using Genetic Insights To Make This Global Crop More Sustainable

Photo, posted November 9, 2008, courtesy of BP Takoma via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And The Next Pandemic | Earth Wise

By Leave a Comment

As the planet continues to heat up, animals big and small are moving towards the poles to escape the heat.  According to researchers, these animals are likely to come into contact with other animals that they normally wouldn’t, and are likely to relocate to regions with large human populations.  These factors create opportunities for pathogens to get into new hosts, which dramatically increases the risk of a viral jump to humans.  Climate change could lead to the next pandemic.      

An international research team led by scientists at Georgetown University recently made this connection between climate change and viral transmission.  In the study, which was recently published in the journal Nature, researchers conducted the first comprehensive assessment of how climate change will restructure the global mammalian virome.  Their work focused on geographic range shifts. 

As animals eccounter other animals for the first time, the study projects that they will share thousands of viruses.  And as animals increasingly move into the same areas as humans, there will be greater opportunities for these viruses to jump to humans.  The research team says that the impact on conservation and human health could be alarming as viruses jump between species at unprecedented rates. 

In our warming world, much of this process may unfortunately already be underway.  And efforts to reduce greenhouse gas emissions may not be enough to stop these events from unfolding. 

According to the study, climate change will become the biggest upstream risk factor for disease emergence, eclipsing deforestation, industrial agriculture, and the wildlife trade.  Pairing wildlife disease surveillance with real-time studies of environmental change may be part of the solution to predicting and preventing the next pandemic. 

**********

Web Links

Climate change could spark the next pandemic, new study finds

Coronavirus and Climate Change

Photo, posted October 16, 2014, courtesy of Shawn Thomas / NPS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

How Quickly Can The Planet Recover? | Earth Wise

By Leave a Comment

Climate change refers to long-term shifts in temperatures and weather patterns.  Historically, these shifts were natural.  But since the Industrial Revolution, scientists have found that the main driver of climate change has been human activities, primarily by adding significant amounts of greenhouse gases into the atmosphere through the burning of fossil fuels. 

Today, climate change is destabilizing Earth’s temperature equilibrium and is having a widespread impact on humans, animals, and the environment.  Some of the consequences of anthropogenic climate change include warmer air and ocean temperatures, shrinking glaciers, increasing spread of pests and pathogens, declining biodiversity, and more intense and frequent extreme weather events. 

But how quickly can the climate recover from the warming caused by an increase in carbon dioxide in the atmosphere? 

Researchers from Johannes Gutenberg-University Mainz in Germany looked into this question by investigating the significant rise in global temperatures that took place 56 million years ago.  Likely triggered by a volcanic eruption,  the increase of between 5 and 8 degrees Celsius was the fastest natural period of global warming that has impacted the climate. 

Because higher temperatures cause rocks to weather faster, the research team decided to analyze the weathering processes that occurred during the warming event 56 million years ago.  Their findings, which were recently published in the Journal Science Advances, indicate that the climate took between 20,000 and 50,000 years to stabilize following the rise in global temperatures.

Climate change is not some distant problem.  It is happening now and it poses a serious threat to all forms of life.  We need to address the problem with more urgency. 

**********

Web Links

How quickly does the climate recover?

Photo, posted August 27, 2017, courtesy of Lt. Zachary West (100th MPAD) / Texas Military Department via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Harnessing The Smell Of Fear | Earth Wise

By Leave a Comment

Plant-eating insects present a major problem for farmers and home gardeners.  Aphids, for example, are a highly destructive pest to many crops.  Their large numbers and ability to transmit plant pathogens make them a persistent problem for growers.

Pesticides are chemical substances that are commonly used to prevent, destroy, repel or mitigate pests.  They include insecticides for insects, rodenticides for rodents, herbicides for weeds, and fungicides for microorganisms.  According to the U.S. Geological Survey, approximately one billion pounds of these chemicals are used in the United States every year.     

But pesticides can also contaminate soil, water, and other vegetation, as well as kill many non-target species.  Exposure to these chemicals is dangerous for human health. 

According to a new study, researchers from Pennsylvania State University have developed a way to bottle the “smell of fear” produced by predators in order to repel and disrupt pests naturally without the need for these harsh substances.  The researchers recently presented their findings at the American Chemical Society meeting.  

Aphids happen to be a favorite food of ladybugs. Aphids and other herbivorous insects will steer clear of fields and gardens if they smell predators nearby.  The researchers identified and extracted the volatile odor profile from ladybugs.  The researchers used the compounds to create a special odor blend that can be used in an essential oil diffuser to spread the scent across a garden or field. 

The research team plans to conduct field tests to see if the effects outside are similar to what was observed in the lab.  A natural and effective pest repellent would be a big win for people and the planet.  

**********

Web Links

Protecting gardens and crops from insects using the ‘smell of fear’

Protecting gardens and crops from insects using the ‘smell of fear’ (YouTube)

Photo, posted May 10, 2011, courtesy of DM via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Protecting Bees From Pesticides | Earth Wise

By Leave a Comment

Studies have shown that the wax and pollen in 98% of beehives in the U.S. are contaminated with an average of six pesticides.  These substances lower bees’ immunity to devastating varroa mites and other pathogens.  By some estimates, pesticides cause beekeepers to lose about a third of their hives every year on average.

Researchers at Cornell University have developed a new technology that effectively protects bees from insecticides.  The insecticide antidote delivery method is now the basis of a new company called Beemunity.

The Cornell researchers developed a uniform pollen-sized microparticle filled with enzymes that detoxify organophosphate insecticides before they are absorbed and can harm bees.  Organophosphate insecticides account for about a third of the insecticides on the market.  The microparticles have a protective casing that allows the enzymes to move past the bees’ crop (basically the stomach), which is acidic and would otherwise break them down.  The safeguarded enzymes then enter the midgut, where digestion occurs and where toxins and nutrients are absorbed.  There the enzymes act to break down and detoxify the organophosphate insecticides.

In experimental tests, bees that were fed the enzyme-filled microparticles had a 100% survival rate after exposure to the insecticide malathion.  Unprotected control bees died within days.

The Cornell work appears to represent a low-cost, scalable solution to the insecticide toxicity issue and may help to protect essential pollinators.

**********

Web Links

Pollen-sized technology protects bees from deadly insecticides

Photo, posted January 30, 2020, courtesy of George Tan via Flick.

Earth Wise is a production of WAMC Northeast Public Radio.

Helping Corals With Beneficial Bacteria | Earth Wise

By Leave a Comment

A group of researchers at the King Abdullah University of Science and Technology in Saudi Arabia is exploring a novel technology to improve the health of corals.  Around the globe, corals are being stressed by pathogens, toxins, and warming waters leading to widespread bleaching events.

The new idea is to introduce beneficial bacteria to the corals, thereby boosting the strength and resilience of their symbiotic partners.  The concept is akin to the use of probiotics in plant science.  Corals rely on bacterial and algal symbionts to provide nutrients, energy (through photosynthesis), toxin regulation, and protection against pathogens.  

The researchers selected bacteria that are naturally symbiotic to specific coral species on reefs in the Red Sea, ensuring that no alien bacteria are accidentally introduced.  A probiotic cocktail comprising six bacteria strains was used in a laboratory setting.  Results in the lab have been promising so far, as they have observed dynamic and metabolic alterations to the corals that boosted their chances of survival under heat stress. 

Success in the lab will need to be translated to success in the open oceans, which is challenging.  Scaling up and seeding whole reefs might involve robots and artificial intelligence in order to deliver probiotics either into sediments or directly onto corals.

The use of beneficial microorganisms is not the solution to the global destruction of coral reefs.  Only worldwide CO2 mitigation can ultimately accomplish that.  But the probiotic approach might buy corals some time as they deal with shifting environmental pressures and try to adapt to a changing world.

**********

Web Links

Microbiome boost may help corals resist bleaching

Photo, posted March 18, 2018, courtesy of Steven dos Remedios via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Turning Food Waste Back Into Food | Earth Wise

By Leave a Comment

Scientists at the University of California Riverside have discovered that fermented food waste can boost bacteria that increase crop growth, make plants more resistant to pathogens, and reduce the carbon emissions resulting from farming.

Food waste is a serious problem from multiple perspectives.  As much as 50% of food is thrown away in the United States and most of that simply ends up in landfills, taking up more than 20% of America’s landfill volume.  Food waste is a huge economic loss as well as a significant waste of freshwater resources used to produce food.

The researchers studied byproducts from two kinds of food waste readily available in Southern California:  beer mash – a byproduct of beer production – and mixed food waste discarded by grocery stores.

Both types of waste were fermented and then added to the irrigation system watering citrus plants in a greenhouse.  Within 24 hours, the average population of beneficial bacteria was two to three orders of magnitude greater than in plants that did not receive the treatments. This led to improvements in the carbon to nitrogen ratio in crops.  When there are enough so-called good bacteria in plants, they produce antimicrobial compounds and metabolites that help plants grow better and faster.

The results of the study suggest that the use of food waste products in agriculture is beneficial and could complement the use of synthetic chemical additives by farmers, perhaps eliminating it entirely.  Crops would in turn become less expensive.

Making use of food waste in agriculture is a step towards a more circular economy in which we use something and then find a new purpose for it.

**********

Web Links

Turning food waste back into food

Photo, posted October 28, 2012, courtesy of Daniel Lobo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Restoring Seagrass In Virginia | Earth Wise

By Leave a Comment

Seagrass is found in shallow waters in many parts of the world.  They are plants with roots, stems, and leaves, and produce flowers and seeds.  They can form dense underwater meadows that constitute some of the most productive ecosystems in the world.  Seagrasses provide shelter and food to a diverse community of animals including tiny invertebrates, fish, crabs, turtles, marine mammals and birds.

In the late 1920s, a pathogen began killing seagrasses off the coast of Virginia.  In 1933, a hurricane finished them off completely.  For nearly 70 years thereafter, the bay bottoms of the Virginia coast were muddy and barren, essentially devoid of fish, shellfish, mollusks and other creatures that inhabit seagrass meadows.  The local scallop industry was no more.

The largest seagrass restoration project ever attempted has changed all that.  During the past 21 years, scientists and volunteers have spread more than 70 million eelgrass seeds within four previously barren seaside lagoons.  This has spurred a natural propagation of meadows that have so for grown to almost 9,000 acres, the largest eelgrass habitat between North Carolina and Long Island Sound.

The long-term research conducted by the team from the University of Virginia shows that the success of the seagrass restoration project is improving water quality, substantially increasing the abundance of fish and shellfish in the bays, and capturing carbon from the water and atmosphere and storing it in the extensive root systems of the grasses and in the sediment below. 

The study shows that marine restorations are possible on scales that contribute directly to human well-being.

**********

Web Links

Some Good News: Seagrass Restored to Eastern Shore Bays is Flourishing

Photo, posted May 17, 2019, courtesy of Virginia Sea Grant via Flickr. Photo credit: Aileen Devlin | Virginia Sea Grant.

Earth Wise is a production of WAMC Northeast Public Radio.

Livestock Expansion And Global Pandemics | Earth Wise

By 1 Comment

The domestication of cows, pigs, chickens, and other animals as livestock for their meat, milk, and eggs was historically revolutionary.  It boosted food security by giving people a readily-available means of feeding themselves as opposed to more traditional methods such as hunting and fishing. 

But animal agriculture has plenty of drawbacks.  The industrialization of animal agriculture has led to horrendous conditions.  Animals are kept in huge quantities and packed together with little regard for their health and welfare.  This approach to agriculture is simply designed to maximize production while minimizing costs. 

With its chemical inputs and toxic outputs, intensive animal agriculture is also a major threat to the environment.  In fact, it’s a major driver of habitat degradation and biodiversity loss all around the globe.   

But it’s not just animals and the planet that pay a price.  Humans have inherited several lethal pathogens from livestock over the years, including the influenza virus that likely jumped to humans from poultry.

According to a study recently published in Biological Conservation,  there is a connection between the global increase in the emergence of infectious diseases and epidemics, the accelerated loss of biodiversity, and the expansion of livestock.  In the study, the research team from the Institute of Evolution Sciences of Montpellier cross referenced databases on human and animal health, livestock expansion, and biodiversity loss between 1960-2019.  The team found that the number of epidemics identified in humans increased in correlation with both biodiversity loss and livestock expansion. 

In the era of COVID-19, it’s important to understand how global livestock expansion directly threatens both human health and the health of the planet. 

**********   

Web Links

Livestock expansion is a factor in global pandemics

Photo, posted July 22, 2018, courtesy of Artem Beliakin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Melting Permafrost | Earth Wise

By Leave a Comment

The Arctic is warming faster than any region on Earth and mostly we’ve been hearing about the rapid disappearance of Arctic sea ice.  But the land in the Arctic is also undergoing major changes, especially to the permafrost that has been there for millennia.

Permafrost occurs in areas where the temperature of the ground remains below freezing for two years or more.  About a quarter of the Northern Hemisphere’s landscape meets this criterion.  Most of the world’s permafrost is found in northern Russia, Canada, Alaska, Iceland, and Scandinavia.

Permafrost regions previously carpeted in cranberries, blueberries, shrubs, sedges, and lichen are now being transformed into nothing but mud, silt, and peat.  So-called regressive thaw slumps – essentially landslides – are creating large craters in the landscape.  (The Batagaika Crater in the Yana River Basin of Siberia is a kilometer long and 100 meters deep).

Apart from the violence being done to the Arctic landscape, the greatest concern is that the permafrost has locked in huge stores of greenhouse gases, including methane, carbon dioxide, and nitrous oxide.  It is estimated that the permafrost contains twice as much carbon as is currently contained in the atmosphere.  As the permafrost thaws, these gases will be released.  With them will be pathogens from bygone millennia whose impact cannot be predicted.  Climatologists estimate that 40% of the permafrost could be gone by the end of the century.

As the permafrost thaws, the region’s ecosystems are changing, making it increasingly difficult for subsistence indigenous people and Arctic animals to find food.  Landslides are causing stream flows to change, lakes to suddenly drain, seashores to collapse, and water chemistry to be altered.

The warming Arctic is about much more than disappearing sea ice.

**********

Web Links

How Thawing Permafrost Is Beginning to Transform the Arctic

Photo, posted February 9, 2017, courtesy of the U.S. Geological Survey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Disease On Coral Reefs

By Leave a Comment

The warming oceans have led to bleaching events in coral reefs around the world, but bleaching is not the only problem corals face.  Disease outbreaks are also becoming more frequent, severe, and widespread.

Many factors are contributing to the problem, including pollution and nitrogen runoff from fertilizers and coastal sewer and septic systems.  However, the key culprit is likely the steadily increasing ocean temperatures, which are the cause of coral bleaching.  Elevated water temperatures can cause coral polyps to expel the algae that sustains them and gives them color. 

According to scientists, bleaching makes corals more susceptible to illness.  In the Caribbean, a coral disease hotspot, about 80% of coral cover has disappeared, largely from outbreaks of “white band disease”, so called because of a white band of dead tissue that forms in affected corals.  Two crucial reef-building species, elkhorn and staghorn coral, are now nearing extinction in the regions.  The reef extending along the Florida coastline is the third largest reef ecosystem in the world and nearly 35% of it has been lost to disease.

Estimates are that disease outbreaks have wiped out at least 6% of the corals on the Great Barrier Reef in Australia.  In that region, diseases are more prevalent in areas where corals were damaged by fishing and other human activity because wounded coral provides an entry point for pathogens and bacteria.

In the face of climate change and mounting disease outbreaks, scientists are scrambling for solutions to stave off catastrophe.  Assisting the migration of hardier coral species and breeding so-called “super corals” are among the strategies being pursued.  It is unknown whether these and other forms of intervention can be used on a wide enough scale to really make a difference.

**********

Web Links

As Disease Ravages Coral Reefs, Scientists Scramble for Solutions

Photo, posted November 29, 2012, courtesy of Robert Linsdell via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

An App For Infection Testing

By Leave a Comment

Researchers at Washington State University have developed a low-cost, portable device that works with a smartphone to detect common viral and bacterial infections nearly as well as clinical laboratories.  Such a system could lead to faster and lower-cost lab results for fast-moving epidemics, especially in rural or lower-resource regions where laboratory equipment and medical personnel are not readily available.

[Read more…] about An App For Infection Testing

How Safe Is Drinking Water?

By Leave a Comment

Water is life.  It’s a fundamental need for every human being on the planet.  Each person requires more than five gallons of clean and safe water a day for drinking, cooking, and keeping clean.  Dirty water, on the other hand, can be deadly.  An estimated 1.8 million people die every year as a result of diarrheal diseases like cholera.  And tens of millions of people are seriously sickened by water-related maladies. 

[Read more…] about How Safe Is Drinking Water?

The Ecology Of Dust

By Leave a Comment

It isn’t something we think about very often, but dust is a connector of ecosystems around the world.  Dust carries various minerals and nutrients to places where such things are in very scarce supply.  This includes the oceans of the world as well as many forests and other ecosystems.  For example, phosphorus-bearing dust carried from the Gobi Desert is essential to the growth of giant redwoods in California’s Sierra Mountains.

[Read more…] about The Ecology Of Dust

Mapping Emerging Infectious Diseases

By

Ebola. Hantavirus. Lyme disease. What do they have in common? Like most emerging infectious diseases, they originated in mammals. So many debilitating pathogens make the jump from wildlife and livestock to humans, yet at the global scale little is known about where people are most at risk of outbreaks.

[Read more…] about Mapping Emerging Infectious Diseases

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)