Sea otters, opossums and the surprising ways pathogens move from land to sea

19th March 2020

by Kat Kerlin, UC Davis

A parasite known only to be hosted in North America by the Virginia opossum is infecting sea otters along the West Coast. A study from the University of California, Davis, elucidates the sometimes surprising and complex pathways infectious pathogens can move from land to sea to sea otter.

For the study, published in the journal Scientific Reports, researchers tested sea otters ranging from Southern California to Alaska for the presence of Sarcocystis neurona, a parasite and important cause of death in sea otters.

They were surprised to find several infected sea otters in the northern part of Vancouver Island in British Columbia, where Virginia opossums—also known as the North American opossum—are not known to live. They wondered: Could this parasite travel very long distances in water, or is there an additional unknown host for this pathogen?

To answer this question, the scientists examined spatial patterns and previous research into pathogen transmission, diet and movement of otters. Their results suggest the pathogen may be carried by water runoff from land to sea, where it can be concentrated through ocean movement and prey species, such as clams.

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Committed to relatives: Hounds and wolves share their parasites

Date:  December 15, 2017

Source:  Forschungsverbund Berlin e.V. (FVB)

Summary:

Grey wolves, as all wild animals, are hosts to a variety of parasites. The presence of grey wolves in German forests has little influence on the parasite burden of hunting dogs, according to a new study.

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Monarch butterfly parasitoids brough to light by citizen science

'Unprecedented view' of parasitoid presence in monarch larval ecology

Date:  July 10, 2017

Source:  Entomological Society of America

Summary:  Scientists now know more than ever about the flies that attack monarch butterfly caterpillars, thanks to citizen science. Since 1999, volunteers participating in the Monarch Larva Monitoring Project have collected and raised more than 20,000 monarch eggs and caterpillars, and they've recorded incidents of those specimens being parasitized by fly larvae.

     

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Long-Lost Tropical Bed Bugs Are Back in the US

By Jen Viegas, Seeker | November 11, 2016 12:27pm ET

After a suspected 60-year absence from the U.S., a bed bug known for its ability to spread rapidly has just invaded Florida and Hawaii, according to experts who study the parasitic pest.

The tropical bed bug Cimex hemipterus is raising concern because traditional eradication methods might not keep its numbers in check.

"To the naked eye, the common bed bug (Cimex lectularius) and the tropical bed bug would look the same, as would signs of their presence: bites, blood spots on linens and shed skin from the bugs," University of Florida entomologist Brittany Campbell told Seeker. She added that the parasites can cause everything from small bite marks to serious allergic reactions that require immediate medical attention.

"Under a microscope, the two species look different," continued Campbell, who recently authored a report on tropical bed bugs for Entomology Today. "The tropical bed bug has a different-shaped pronotum, or neck-like structure, that doesn't have the 'U-shape' characteristic of common bed bugs."

The bed bug's existence in Hawaii is anecdotal, she said, but more is known about its presence in Florida, thanks to an observant homeowner from Merritt Island near the Ulumay Wildlife Sanctuary in Brevard County, Fla. In 2015 the family reported an infestation, and a sample was sent to Campbell. She and her team discovered the bed bug was from the long-lost tropical species.

From the late 1930s to the early 1940s, the bug was found in several Florida counties. But it hadn't been reported again until the Merritt Island incident. As its name suggest, it's often found in tropical environments including Africa, parts of Australia, Asia and South America.



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Sunflower pollen protects bees from parasites

Why eat nasty things? Because your enemy finds it even nastier

Date: June 14, 2016

Source: University of Chicago Press Journals

Plant pollens vary in quality as food sources for bees, and pollen from the sunflower family (the family that includes dandelions, daisies, and thistles) is known to have some unpleasant qualities. Bees fed exclusively sunflower pollen often develop poorly, slowly, or not at all. Yet many bee species collect pollen exclusively from this family; in fact, specialization on sunflower pollen has evolved multiple times in bees. Research by Dakota Spear and colleagues suggests that parasites could be part of the explanation.

Sarah Silverman, at the time a McGill University undergraduate doing summer research on solitary mason bees at the Rocky Mountain Biological Laboratory (RMBL) in Colorado, USA (with University of Ottawa professor Jessica Forrest), noticed that bee species specializing on sunflower pollen were not attacked by a common brood-parasitic wasp, Sapyga. The wasp frequently lays eggs in the nests of other mason bee species, where its larvae kill bee eggs and eat their pollen provisions.

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Genomes of chimpanzee parasite species reveal evolution of human malaria

Date: March 22, 2016

Source: University of Pennsylvania School of Medicine

An international team of scientists used an amplification technique to sequence the genomes of two divergent Plasmodium malaria species from miniscule volumes of chimpanzee blood to find clues about the evolution and pathogenicity of Plasmodium falciparum, the deadliest malaria parasite that affects people. Understanding the origins of emerging diseases -- and more established disease agents -- is critical to gauge future human infection risks and find new treatment and prevention approaches.

Understanding the origins of emerging diseases -- as well as more established disease agents -- is critical to gauge future human infection risks and find new treatment and prevention approaches. This holds true for malaria, which kills more than 500,000 people a year. Symptoms, including severe anemia, pregnancy-associated malaria, and cerebral malaria, have been linked to the parasite's ability to cause infected red blood cells to bind to the inner lining of blood vessels.

An international team led by Beatrice Hahn, MD, a professor of Medicine and Microbiology from the Perelman School of Medicine at the University of Pennsylvania, and MD/PhD student Sesh Sundararaman, used a selective amplification technique to sequence the genomes of two divergent Plasmodium species, Plasmodium reichenowi and Plasmodium gaboni, from miniscule volumes of chimpanzee blood to find clues about the evolution and pathogenicity of Plasmodium falciparum, the deadliest malaria parasite that affects people. Their findings appear this week in Nature Communications.

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Flowers can endanger bees

Entomologists show flowers serve as parasite-dispersing hubs

Date:

August 4, 2015

Source:

University of California - Riverside

Summary:

Flowers can pose a grave danger to bees, a team of researchers has determined. The study is the first to show that not only can bees disperse parasites around the environment but also that flowers are platforms for a host of pollinator parasites subsequently dispersed onto visiting bees. The finding may affect the national and international trade of flowers unless sterilization of parasites on these flowers can be guaranteed.

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New strains of parasites identified: Research on whipworms has implications for human health and animal conservation

Date:

January 12, 2015

Source:

McGill University

Summary:

Researchers have discovered that there are three genetically distinct groups of whipworms – and only one of the three appears to be transmissible between humans and non-human primates. It is important information for public health officers around the world.

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Parasites and the evolution of primate culture

Learning from others and innovation have undoubtedly helped advance civilization. But these behaviours can carry costs as well as benefits. And a new study by an international team of evolutionary biologists sheds light on how one particular cost - increased exposure to parasites - may affect cultural evolution in non-human primates.

The results, published Dec. 3, 2014, in the journal Proceedings of the Royal Society B, suggest that species with members that learn from others suffer from a wider variety of socially transmitted parasites, while innovative, exploratory species suffer from a wider variety of parasites transmitted through the environment, such as in the soil or water.

"We tend to focus on innovation and learning from others as a good thing, but their costs have received relatively little attention," says McGill University biologist Simon Reader, co-author of the study. "Here, we uncover evidence that socially transmitted pathogen burdens rise with learning from others - perhaps because close interaction is needed for such learning - and environmentally transmitted pathogen burdens rise with exploratory behaviour such as innovation and extractive foraging."

Read more at: 

Wild sheep show benefits of putting up with parasites

Date:

August 7, 2014

Source:

Princeton University

Summary:

In the first evidence that natural selection favors an individual's infection tolerance, researchers have found that an animal's ability to endure an internal parasite strongly influences its reproductive success. The finding could provide the groundwork for boosting the resilience of humans and livestock to infection.

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The parasite that escaped out of Africa: Tracing origins of malaria parasite

Date:

February 21, 2014

Source:

Perelman School of Medicine at the University of Pennsylvania

Summary:

An international team has traced the origin of the second-worst malaria parasite of humans to Africa. The closest genetic relatives of human Plasmodium vivax were found only in Asian macaques, leading researchers to believe that P. vivax originated in Asia. This study overturns that, finding that wild-living apes in central Africa are widely infected with parasites that, genetically, are nearly identical to human P. vivax.

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Harlequin ladybirds escape natural 'enemies'

Harlequin ladybirds escape parasites which attack native species, scientists have found.

Harlequin ladybirds settled in the UK from Asia in 2004 and rapidly spread across the country.

The decline of several native ladybird species has been attributed to the arrival of these invasive insects.

Experts studying the invasion found that the harlequins were significantly less susceptible to parasites which prey on native ladybirds.

The results are published in the journal Insect Conservation and Diversity.

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This Castle’s Toilet Still Holds Parasites From Crusaders’ Feces

Cyprus, the Mediterranean island nation just south of Turkey, took centuries to gain its independence. The Greeks, Assyrians, Egyptians, Persians, Romans, Ottomans, British and others all took their turns taking over the island, and each left their mark on the archeological record. But in a ruined chamber in a castle on the western corner of the island, it may be more apt to say the invaders left a smear.

In 1191, during the Third Crusade, King Richard I of England invaded Cyprus and ordered that a castle be built on the island’s western corner in order to defend the harbor there. Called Saranda Kolones, the castle’s name refers to its many monolithic columns. But in typical tumultuous Cyprus fashion, the medieval castle was only used for thirty years before it was destroyed by an earthquake. By then, King Richard had sold Cyprus to Guy de Lusignan, the King of Jerusalem. Lusignan and his successors had other plans for expanding the island. The wrecked port was abandoned and the castle never rebuilt. 

As castles go, Saranda Kolones had a pretty poor run. But two University of Cambridge researchers recently realized that, precisely thanks to the castle’s short use, a priceless treasure had been left behind in the Saranda Kolones’ bowels. One of the centuries-old castle latrines (read: ancient toilet), they found, was still full of dried-up poo. That feces, they thought, could provide valuable insight into what kind of parasites plagued the former residents’ guts. And because only 30 years’ worth of waste clogged the ancient sewage system, those parasites could provide specific insight into what ailed medieval crusaders. The researchers rolled up their sleeves and collected samples from the dessicated cesspool.

To rehydrate the ancient night soil, the team placed one gram of their sample into a chemical liquid solution. They used micro sieves, or tiny strainers to separate parasite eggs from the digested remains of the crusaders’ meals. They created 20 slides, and peeked into their microscopes to see what creatures the soldiers may have left behind.

Read more: http://blogs.smithsonianmag.com/science/2013/06/this-castles-toilet-still-holds-parasites-from-crusaders-feces/#ixzz2XDiwmeTF

Treating Infection May Have Sting in the Tail, Parasite Study Shows

June 17, 2013 — Using drugs to treat an infection could allow other co-existing conditions to flourish, a study in wild animals has shown.

Researchers studying wild mice -- which typically carry multiple parasitic infections at once -- found that when these animals were treated for one type of bug, other infections they had tended to worsen.

The findings suggest that infections that co-exist in our bodies can compete with each other to alter disease. Treating one infection may have unintended consequences by enabling others to gain a stronger foothold -- perhaps to the overall detriment of our health.

Scientists from the University of Edinburgh treated wild wood mice for a gut worm infection over several weeks. During treatment, researchers monitored levels not only of the worm, but also tested the animals for dozens of other common parasite infections. During treatment, levels of the gut worm fell, but levels of other parasites in the gut increased.

The study is the first of its type to show that multiple infections in wild animals can compete with one another, and that treating one infection can directly impact on others that may be present.

The study, published in Proceedings of the Royal Society B, was carried out in collaboration with The University of Liverpool and supported by the Natural Environment Research Council and the Wellcome Trust.

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Lifestyle of a Killer: In Wild European Brown Shrimp, Parasitic Dinoflagellates Have Bacteria-Like Endosymbionts

ScienceDaily (Sep. 7, 2012) — Parasitic dinoflagellates of the genus Hematodinium are a big problem for crab, prawn and shrimp fisheries across the world. New research published in BioMed Central's open access journal Aquatic Biosystems has found that, in wild European brown shrimp (Crangon crangon), these parasites have bacteria-like endosymbionts. The presence of these endosymbionts indicates a previously unknown side to the lifecycle of Hematodinium.

Hematodinium sp. and its sister species H. Perezi are a real problem for blue crab fishers , causing 'bitter crab' disease, and are thought to be responsible for the decline of blue crabs in Chesapeake Bay. But they are not fussy. Over 40 species of crustaceans are known to be infected by these nasty parasites.

A collaboration between researchers at the European Union Reference Laboratory for Crustacean Diseases (CEFAS) and the Virginia Institute of Marine Sciences (VIMS) identified the parasite responsible for causing sickness in wild European brown shrimp, collected from the North Sea, as Hematodinium sp.. These shrimp had lost carapace transparency and their blood (haemolymph) had lost the ability to clot. The invading Hematodinium had also infiltrated the muscles, destroyed internal organs, and the infection had damaged the shrimp's ovaries, affecting their ability to reproduce. Adding insult to injury the shrimp were also infected with Crangon crangon bacilliform virus (CcBV).

Read on:  http://www.sciencedaily.com/releases/2012/09/120906203351.htm

300,000 Caribou Huddle Together To Avoid Insects

Humans are not the only creatures bothered by mosquitoes and flies. They harass caribou so much that earlier this month, about 300,000 of the animals huddled closely together in Northwest Alaska to avoid being bitten and parasitized.

It's one of the most spectacular gatherings of wildlife in the world, rivaling the migratory herds of Africa's Serengeti, said Kyle Joly, a wildlife biologist with the National Park Service based in Fairbanks, Alaska.

Joly took several photos of the animals while flying a Cessna 185 earlier this month, near Cape Krusenstern National Monument and Noatak National Preserve.

"The bugs on the North Slope are pretty ferocious," Joly told OurAmazingPlanet. "The mosquitoes just harass them 24 hours per day." The warble flies and nasal bots that are out now are even worse in some ways, he said; the warbles try to lay eggs on the animal's sides and the bots try to fly up caribou nostrils to deposit eggs.

Continued:  http://www.livescience.com/21718-caribou-herds-bug-protection.html

What It Takes to Be the Perfect Invading Parasite

ScienceDaily (July 17, 2012) — Scientists from the Zoological Society of London (ZSL) are the first to document the characteristics of invading parasites, using malaria in New Zealand bird species.

The study, published July 18 in Ecology Letters, identifies the factors influencing the success of parasites unintentionally introduced to new environments.

Avian malaria is a disease caused by species of parasites, of the genus Plasmodium, which infects birds. Just like human malaria, it is spread by mosquitoes, and the parasites spend part of their lives in red blood cells of birds. Avian malaria is common in continental areas, but is often absent from isolated islands where mosquitoes are less prevalent.

More than 800 exotic and native host birds were studied in a range of areas across Northern New Zealand. They detected parasite infection by extracting DNA from blood and analyzing it to look at specific segments of genes. They then looked in more detail at the characteristics of the parasites they found to see if they had features that made them more likely to be present in bird hosts in New Zealand.

Continued:   http://www.sciencedaily.com/releases/2012/07/120718074033.htm 

Why More Parasite Diversity is Good News for Frogs-Flukes that parasitize amphibians – via Herp Digest

Discover Magazine Blog 5/24/12

The enemy of my enemy is my friend—especially if I’m a frog and my enemies are competing parasites. A recent study in PNAS found that frogs populations exposed to a more diverse set of flukes actually had lower rates of infection, with fewer frogs in the group afflicted with tiny hitchhikers.

Researchers at the University of Colorado-Boulder bred Pacific chorus frogs in a lab and put their tadpoles in different tanks with anywhere from one to six different types of flukes. On average, 40% of the frogs that came into contact with only a single fluke species developed infections, while 34% of frogs exposed to four flukes and 23% of frogs exposed to six flukes were infected (the numbers for two, three flukes followed a roughly similar trend). Additionally, some of the fluke species make frogs sicker than others, and oddly enough, the frogs exposed to a greater variety of flukes had a lower proportion of infections from these dangerous species.

Most research on host-parasite interactions has focused one host–one parasite, but as this study shows, it’s a lot more complicated in the natural world. Preserving biodiversity—even biodiversity of creatures, whether flukes or microbes, that we’re not fond of—might be an important part of keeping disease down. Why that is isn’t exactly clear—the scientists who did this study, for instance, aren’t sure why frogs were better off with lots of flukes around.

But it could be analogous to what happens in humans who have the biodiversity of their gut microbes disturbed by antibiotics. Once healthy, or at least relatively harmless, microbes are wiped out, it’s easy for dangerous bacteria like C. difficile to take over their real estate and cause life-threatening disease. Something similar seems to happen with viruses: having certain viruses in your body can keep you from getting infected by other, more harmful pathogens.

In fighting off infections, thus, it could help to have allies among the enemy.

More Parasites Mean Healthier Frogs

Parasites seem to be each other's worst enemy, and a frog's best friend, new research indicates. Increases in the diversity of parasites that attack amphibians cause a decrease in the infection success rate of those parasites.

"Collectively, our findings illustrate the importance of considering the hidden role of parasite diversity in affecting disease risk," study researcher Pieter Johnson, of the University of Colorado, said in a statement. "While our study was on amphibian diseases, there is ample evidence to suggest similar processes can be occurring in humans and other groups of animals."

Scientists are concerned about how changes in biodiversity affect the risk of infectious diseases in humans and wildlife. Charting the relationships between parasites and amphibians is important since few studies have examined the influence of parasite diversity on disease, and the fact that amphibians are declining faster than any group of animals on the planet due to human activities like habitat loss, pollution and emerging diseases, Johnson said.

In the new study, the team sampled 134 California ponds for parasites, known as trematodes, comparing their abundance and distribution with the health of more than 2,000 Pacific chorus frogs in those ponds. The researchers compared their data from the field studies with extensive lab experiments that charted the health of the frogs in the presence of different combinations of six common amphibian parasites.

Continued:  http://www.livescience.com/20477-parasites-healthier-frogs.html

Locating Lice as They Hitch-Hike With Birds for Life

ScienceDaily (May 14, 2012) — Although chewing lice spend their entire lives as parasites on birds, it is difficult to predict patterns of lice distribution, new research from the University of Gothenburg, Sweden, reveals.

Researcher Daniel Gustafsson has studied chewing lice on sandpipers around the world and investigated how host birds' migration patterns affect louse distribution and relationships.

With no wings and very small eyes, chewing lice are, by and large, helpless away from their host.

Daniel Gustafsson has studied species of chewing lice that live on the birds' wings and compared them with species that live on their body feathers.

"Given that chewing lice are almost totally dependent on direct contact between two birds to spread, lice that sit on birds' wings should find it easier to use occasional contact between two hosts to spread than those that sit closer to birds' bodies," Daniel Gustafsson says.

Read on:   http://www.sciencedaily.com/releases/2012/05/120514134259.htm