Melissa Bailey: West Nile Virus loves global warming

Global distribution of the West Nile Virus. There have been many cases in southern New England.

From Kaiser Health News

“West Nile Virus is a really important case study” of the connection between climate and health.

—Dr. Gaurab Basu, a primary-care physician and health-equity fellow at the Center for Climate, Health and the Global Environment at Harvard’s public health school.

Michael Keasling, of Lakewood, Colo., was an electrician who loved big trucks, fast cars and Harley-Davidsons. He’d struggled with diabetes since he was a teenager, needing a kidney transplant from his sister to stay alive. He was already quite sick in August when he contracted West Nile Virus after being bitten by an infected mosquito.

Keasling spent three months in hospitals and rehab, then died on Nov. 11 at age 57 from complications of West Nile Virus and diabetes, according to his mother, Karen Freeman. She said she misses him terribly.

“I don’t think I can bear this,” Freeman said shortly after he died.

Spring rain, summer drought and heat created ideal conditions for mosquitoes to spread West Nile through Colorado last year, experts said. West Nile killed 11 people and caused 101 cases of neuroinvasive infections — those linked to serious illness such as meningitis or encephalitis — in Colorado in 2021, the highest numbers in 18 years.

The rise in cases may be a sign of what’s to come: As climate change brings more drought and pushes temperatures toward what is termed the “Goldilocks zone” for mosquitoes — not too hot, not too cold — scientists expect West Nile transmission to increase across the country.

“West Nile Virus is a really important case study” of the connection between climate and health, said Dr. Gaurab Basu, a primary-care physician and health-equity fellow at the Center for Climate, Health, and the Global Environment at Harvard’s public-health school.

Although most West Nile infections are mild, the virus is neuroinvasive in about 1 in 150 cases, causing serious illness that can lead to swelling in the brain or spinal cord, paralysis, or death, according to the Centers for Disease Control and Prevention. People older than 50 and transplant patients like Keasling are at higher risk.

Over the past decade, the U.S. has seen an average of about 1,300 neuroinvasive West Nile cases each year. Basu saw his first one in Massachusetts several years ago, a 71-year-old patient who had swelling in his brain and severe cognitive impairment.

“That really brought home for me the human toll of mosquito-borne illnesses and made me reflect a lot upon the ways in which a warming planet will redistribute infectious diseases,” Basu said.

A rise in emerging infectious diseases “is one of our greatest challenges” globally, the result of increased human interaction with wildlife and “climatic changes creating new disease transmission patterns,” said a major United Nations climate report released Feb. 28. Changes in climate have already been identified as drivers of West Nile infections in southeastern Europe, the report noted.

The relationship between lack of rainfall and West Nile Virus is counterintuitive, said Sara Paull, a disease ecologist at the National Ecological Observatory Network in Boulder, Colo., who studied connections between climate factors and West Nile in the U.S. as a post-doctoral researcher at the University of California-Santa Cruz.

“The thing that was most important across the nation was drought,” she said. As drought intensifies, the percentage of infected mosquitoes goes up, she found in a 2017 study.

Why does drought matter? It has to do with birds, Paull said, since mosquitoes pick up the virus from infected birds before spreading it to humans. When the water supply is limited, birds congregate in greater numbers around water sources, making them easier targets for mosquitoes. Drought also may reduce bird reproduction, increasing the ratio of mosquitoes to birds and making each bird more vulnerable to bites and infection, Paull said. And research shows that when their stress hormones are elevated, birds are more likely to get infectious viral loads of West Nile.

A single year’s rise in cases can’t be attributed to climate change, since cases naturally fluctuate by year, in part due to cycles of immunity in humans and birds, Paull said. But we can expect cases to rise with climate change, she found.

Increased drought could nearly double the number of annual neuroinvasive West Nile cases across the country by the mid-21st Century, and triple it in areas of low human immunity, Paull’s research projected, compared with averages from 1999 to 2013.

Drought has become a major problem in the West. The Southwest endured an “unyielding, unprecedented, and costly drought” from January 2020 through August 2021, with the lowest precipitation on record since 1895 and the third-hottest daily average temperatures in that period, a National Oceanic and Atmospheric Administration report found.

Spring rain, summer drought and heat created ideal conditions for mosquitoes to spread the West Nile virus throughout Colorado last year. West Nile killed 11 people and caused 101 cases of neuroinvasive infections in Colorado ― the highest numbers in 18 years.

“Exceptionally warm temperatures from human-caused warming” have made the Southwest more arid, and warm temperatures and drought will continue and increase without serious reduction of greenhouse gas emissions, the report said.

Ecologist Marta Shocket has studied how climate change may affect another important factor: the Goldilocks temperature. That’s the sweet spot at which it’s easiest for mosquitoes to spread a virus. For the three species of Culex mosquitoes that spread West Nile in North America, the Goldilocks temperature is 75 degrees Fahrenheit, Shocket found in her post-doctoral research at Stanford University and UCLA. It’s measured by the average temperature over the course of one day.

“Temperature has a really big impact on the way that mosquito-transmitted diseases are spread because mosquitoes are cold-blooded,” Shocket said. The outdoor temperature affects their metabolic rate, which “changes how fast they grow, how long they live, how frequently they bite people to get a meal. And all of those things impact the rate at which the disease is transmitted,” she said.

In a 2020 paper, Shocket found that 70 percent of people in the U.S. live in places where average summer temperatures are below the Goldilocks temperature, based on averages from 2001 to 2016. Climate change is expected to change that.

“We would expect West Nile transmission to increase in those areas as temperatures rise,” she said. “Overall, the effect of climate change on temperature should increase West Nile transmission across the U.S. even though it’s decreasing it in some places and increasing it and others.”

Janet McAllister, a research entomologist with the CDC’s Division of Vector-Borne Diseases, in Fort Collins, Colo., said climate change-influenced factors like drought could put people at greater risk for West Nile, but she cautioned against making firm predictions, since many factors are at play, including bird immunity.

Birds, mosquitoes, humans and the virus itself may adapt over time, she said. For instance, hotter temperatures may drive humans to spend more time indoors with air conditioning and less time outside getting bitten by insects, she said.

Climate factors like rainfall are complex, McAllister added: While mosquitoes do need water to breed, heavy rain can flush out breeding sites. And because the Culex mosquitoes that spread the virus live close to humans, they can usually get enough water from humans’ sprinklers and birdbaths to breed, even during a dry spring.

West Nile is preventable, she noted: The CDC suggests limiting outdoor activity during dusk and dawn, wearing long sleeves and bug repellent, repairing window screens, and draining standing water from places like birdbaths and discarded tires. Some local authorities also spray larvicide and insecticide.

“People have a role to play in protecting themselves from West Nile Virus,” McAllister said.

In the Denver suburbs, Freeman, 75, said she doesn’t know where her son got infected.

“The only thing I can think of, he has a house, they have a little baby swimming pool for the dogs to drink out of,” she said. “So maybe the mosquitoes were around that, I don’t know.”

Melissa Bailey is a Kaiser Health News reporter.

@mmbaily

Invasive little pet turtles

Red-Eared Sliders

From ecoRI News (ecori.org)

They are the most popular pet turtle in the United States and available at pet shops around the world, but because Red-Eared Sliders live for about 30 years, they are often released where they don’t belong after pet owners tire of them. As a result, they are considered one of the world’s 100 most invasive species by the International Union for the Conservation of Nature.

Southern New England isn’t immune to the problems they cause.

“I hear the same story again and again,” said herpetologist Scott Buchanan, a wildlife biologist for the Rhode Island Department of Environmental Management. “‘We bought this turtle for a few dollars when Johnny was 8, he had it for 10 years and now he’s going to college, so we put it in a local pond.’ That’s been the story for hundreds and thousands of kids in recent decades.”

Red-Eared Sliders are native to the Southeast and south-central United States and northern Mexico, where they are commonly found in a variety of ponds and wetlands. Buchanan said they are tolerant of human disturbance and tolerant of pollution, and they are dietary generalists, so they can live almost anywhere. And they do. They breed throughout much of Australia as a result of pets being released, and in Southeast Asia they are raised as an agricultural crop and have displaced numerous native species. In the Northeast, they live in the same habitat as Eastern Painted Turtles, one of the area’s most common species, but they grow about 50 percent larger. Numerous studies suggest that sliders outcompete native turtles for food, nesting, and basking sites.

Despite concerns about their impact on native turtle populations, red-eared sliders are still legal to buy in Rhode Island and most of the United States, though Buchanan said that in the Ocean State they may only be sold by a licensed pet dealer and can’t be transported across state lines. Those who buy a slider must keep it indoors and must never release it into the wild, including into a private pond.

“But people often aren’t aware of the regulations, or they don’t bother to look at them, or they just don’t follow them,” Buchanan said. “We see lots of evidence of sliders, especially in parts of the state where there are lots of people. The abundance of Red-Eared Sliders in Rhode Island is tied to human population density, which means mostly Providence and the surrounding communities. But I’ve also found them in Newport and Narragansett and elsewhere.”

Sliders are especially common in the ponds at Roger Williams Park, in Providence, and in the Blackstone River.

While conducting research for his doctorate at the University of Rhode Island from 2013 to 2016, Buchanan surveyed ponds throughout the state looking for spotted turtles, a species of conservation concern in the region. During his research, he also documented other turtle species, including many red-eared sliders.

“The good news was that while spotted turtles can occupy the same habitat as red-eared sliders, I found a greater probability of occupancy by spotted turtles at the opposite end of the human density spectrum as I found sliders,” he said. “Spotted turtles tend to occur where human population density is low, so at least at this moment in time, we would not expect red-eared sliders to be directly competing with populations of spotted turtles.”

Nonetheless, Buchanan advocates what he calls a “containment policy” to keep the sliders from expanding their range in the state.

“It’s mostly about public education,” he said. “We want to make sure people know not to release them in their local wetlands. If we found sliders in an important conservation area — Arcadia, for example — we might consider removing them, though we’re not doing that now.

“They’re well-established in Rhode Island now, so the thought of eradicating them does not seem like a feasible management solution. We just have to live with them, but we also have to try to minimize their spread and colonization of new wetlands.”

No other non-native turtle from the pet trade besides the Red-Eared Slider has been found to be a common sight in the wild in Rhode Island, though Buchanan said he recently had a report of a Russian tortoise — another popular pet — that was discovered wandering around Coventry.

For those who want to get rid of a pet Red-Eared Slider, Buchanan doesn’t offer any easy alternatives.

“You’ve got to be committed to housing that turtle for 30 or 40 years until it dies,” he said. “That’s why this is such a problematic issue. It’s easy to buy a teeny turtle for ten bucks and think it’s no big deal, but that animal is going to live for a long time. When you purchase it, you have to be responsible for it for the rest of the turtle’s life.”

Rhode Island resident and author Todd McLeish runs a wildlife blog.

Todd McLeish: The decline of other N.E. pollinators

Rusty patched bumblebees, listed on the U.S. Fish & Wildlife Service’s Endangered Species List, once occupied grasslands and tallgrass prairies of the Northeast and Upper Midwest, but most of these habitats have been lost or degraded.

— U.S. Fish and Wildlife Service

From ecoRI News (ecori.org)

Most of the many news reports about the decline of bees and other pollinators focus on only one side of the story: the drop in honeybee numbers because of colony collapse disorder and its impact on food crops. Yet, as important as that issue is to human food security, it only affects one pollinator species, the European honeybee, a non-native species that is managed by commercial beekeepers.

The decline of native pollinators, of which there are thousands of species in North America that affect thousands of additional species of plants and animals, is largely ignored. Robert Gegear is trying to change that.

The assistant professor of biology at the University of Massachusetts at Dartmouth has launched a citizen science program called the Beecology Project to learn more about the ecology of native pollinators, starting with bumblebees, to better understand why some species are doing so poorly while others remain common.

“The survival of native pollinators has a positive cascading effect on so many other species, both the wild plants they pollinate and the other wildlife using those plants for food, shelter, and nest sites,” Gegear said. “Collectively, those relationships are increasing ecosystem health. But as we start to remove pollinators, we start to affect all these other species.

“Certain pollinators are heading toward extinction, but an equal or greater number have not been affected and are increasing. In ecology, it’s about diversity — not how many individuals you see but how many species you see, since each species has a connection with a flowering plant that has a connection to other species.”

For example, Gegear noted that Bombus impatiens, the common eastern bumblebee, is abundant, expanding, and easy to attract to flower gardens, but many other bumblebee species that used to be common are declining rapidly. Why that is happening is unknown.

“It could be that whatever we’re doing to the environment to drive declines in many species of bumblebees is having a direct positive impact on Bombus impatiens,” he said. “We use a lot of non-native plants in our gardens, and Bombus impatiens loves non-native plants, but other bumblebees don’t like non-natives. That’s one possibility. Or impatiens could be more flexible in its use of nest site habitat. We may be removing habitat that supports species that are less flexible in their nesting requirements. We have evidence for both explanations.”

Among the species formerly common in southern New England and are now quite rare are the yellow-banded bumblebee, the yellow bumblebee, the half-black bumblebee and the rusty patched bumblebee. The U.S. Fish & Wildlife Service recently added the rusty patched bumblebee to the Endangered Species List.

The populations of some of these rare species declined especially fast. When Gegear was conducting his doctoral research in the late 1990s, the yellow-banded bumblebee was so abundant that he considered it a pest. Five years later, however, and he couldn’t find it for miles around his research sites.

“The problem is that we don’t know enough about the natural history of most of these species,” he said. “We know virtually nothing about their nesting preferences, about their overwintering preferences, their floral preferences. They have those preferences for a reason, but if you look at plant lists for bumblebees, everything is equal for all species, and that’s not the case.”

Since little is known about which flowers the rare species prefer, many of the growing number of pollinator gardens being installed around the region aren’t benefitting the species most in need. Instead, they’re just helping the species that are already common.

“People want to help, and they have good intentions, but the science isn’t there to tell them what they should be planting,” Gegear said. “I’m trying to fill in those gaps and change the focus of pollinator research by taking more of an ecological approach.”

To do so, he needs large amounts of data. To collect that data, he has turned to the general public. He teamed with computer scientists at Worcester Polytechnic Institute to develop a web-based app to enable anyone to take photos and videos of bumblebees they see, identify them to species, identify the flowers they are visiting, and submit to Gegear’s database.

Based on the data he has already received, new populations of the rare bumblebee species have been found that will enable him to establish new research sites to learn more about those species. Many participants in the program are even planting gardens with the flowers those rare species prefer to boost those bumblebee populations.

Female monarch butterfly.

From ecoRI News

It’s not just bumblebee preferences that are little known. The same is true of the floral preferences of other pollinators. Gegear plans to expand his app to include observations of butterflies and other types of bees. Eventually, he hopes to expand it further so it can be used to conserve pollinators across the country.

“I put a plant on my property last year that we learned one species prefers, and as soon as it came into bloom, the threatened species came in,” he said. “So this approach really does work.”

Gegear is seeking to recruit more Beecology Project volunteers from throughout the region.

“And if you don’t want to use the app, just take a 10-second video of any bumblebee you see and send it to me,” he said. “That’s just as good.”

Rhode Island resident and author Todd McLeish runs a wildlife blog.

Wind-farm configurations

From Robert Whitcomb’s “Digital Diary,’’ in GoLocal24.com

Predictability and standardization are generally sought by businesses, large and small. Thus it should be good news that five companies seeking to set up offshore wind-turbine farms off southern New England have agreed to a common layout for their projects: a standard east-west orientation, with each turbine a nautical mile apart. That’s mostly to try to satisfy fishermen, some of whom express the (exaggerated) fear that the wind farms would reduce their ability to maneuver.

The five companies are Vineyard Wind, Eversource Energy, Mayflower Wind, Orsted North America and Equinor Wind.

The Trump administration, in thrall to the Red State-based fossil-fuel industry, seems to be using some fishermen’s complaints as cover in trying to stop some big renewable-industry projects, which the regime, as with “green energy’’ projects in general, associates with Democrats.

An irony in all this is that the supports for turbine towers act as reefs that attract fish.

The long debate about offshore wind farms continues as signs rapidly multiply that global warming caused by burning oil, gas and coal is accelerating, along with the damage it’s doing, although most people are not yet concerned enough about the crisis to push for serious political and policy action to reverse it. Some of those actions would indeed be quite inconvenient.