Nav: Home

Hookworms employ live fast/die young strategy in fur seal pup hosts

September 20, 2018

Hookworms exploit a live fast/die young strategy in their South American fur seal pup hosts, report Morris Animal Foundation-funded researchers at the University of Georgia. As a result, they often kill their host, rather than finding a happy equilibrium. Scientists are concerned that this type of hookworm infection could eventually pose a risk to critically endangered populations of fur seals.

The research, recently published in the International Journal for Parasitology: Parasites and Wildlife, showed that by adapting to the seals' breeding cycles, this Uncinaria species has evolved to live only 30 to 65 days in the pups' intestines. This forces the worms to feed at a constant rate before they produce eggs and die. The result is high levels of anemia in pups, with more than 20 percent dying of parasitic infections every year.

"Usually we find that most parasites will try and find an equilibrium with a host, so they will extract just enough resources for their own transmission and their own reproductive success," said Dr. Mauricio Seguel, a research fellow at the University of Georgia. "What we found is a very unusual relationship, but one that is well synchronized to a short window of time."

The team studied a reproductive colony of about 3,000 South American fur seals on Guafo Island, in southwestern Chile. During the 2014 and 2015 birthing seasons, the team measured, weighed and took blood and fecal samples from the same randomly selected newborn pups every five to 10 days for 10 weeks. The sampling allowed researchers to follow infections beginning at initial transmission, as well as monitor the pups' health status.

The study showed hookworms feed from their hosts at a constant rate, regardless of how many other hookworms are in the intestine. Further, despite reaching high within-host densities, female hookworms do not decrease egg output. Pups with a higher burden of parasites experience anemia and mortality and release more hookworms into the soil through their feces.

Fur seal pups acquire hookworms during their first days of life, through their mothers' colostrum. Before this, larvae live in the soil, then penetrate a female's skin and live in her subcutaneous tissue until she is pregnant, when they migrate to her mammary glands.

Researchers believe the hookworms' short lifespans have evolved to synchronize with the fur seals' reproductive cycles. Due to the harsh environment on Guafo Island, hookworm larvae survival time in the soil is very limited as storms will wash many to sea. During birthing season, though, fur seals congregate in large groups on the beach. If hookworms can produce as many eggs as possible, as soon as possible, during this time, they provide greater the chances for their larvae to find a female's skin to penetrate.

"This study really allows us to know our enemy. Now that we better understand how these parasites live, we can begin to learn how to control the problem to avoid the worst consequences," said Dr. Kelly Diehl, Morris Animal Foundation Interim Vice President of Scientific Programs. "This particular population is stable, but other populations of fur seals are critically endangered. If they were infected with this disease, we now know when we could potentially intervene to protect fur seal pups and increase survival."
-end-
About Morris Animal Foundation

Morris Animal Foundation's mission is to bridge science and resources to advance the health of animals. Founded by a veterinarian in 1948, we fund and conduct critical health studies for the benefit of all animals. Learn more at morrisanimalfoundation.org.

Morris Animal Foundation

Related Parasites Articles:

Deciphering plant immunity against parasites
Nematodes are a huge threat to agriculture since they parasitize important crops such as wheat, soybean, and banana; but plants can defend themselves.
Malaria parasites 'walk through walls' to infect humans
Researchers have identified proteins that enable deadly malaria parasites to 'walk through cell walls' -- a superpower that was revealed using the Institute's first insectary to grow human malaria parasites.
Scientists analyze dispersal of parasites by birds in the Americas
An international study investigates transmission of microorganisms that cause malaria and other diseases from migratory to resident avian species.
What's the buzz on bee parasites?
Published today in the open-access journal GigaScience is an article that presents the genome sequence and analysis of the honey bee parasitic mite T. mercedesae.
Major drug initiatives are best way to curb threat from parasites
Large-scale programmes to treat a life-threatening disease could improve the health of millions despite concerns about their long-term effects, a study suggests.
More Parasites News and Parasites Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#534 Bacteria are Coming for Your OJ
What makes breakfast, breakfast? Well, according to every movie and TV show we've ever seen, a big glass of orange juice is basically required. But our morning grapefruit might be in danger. Why? Citrus greening, a bacteria carried by a bug, has infected 90% of the citrus groves in Florida. It's coming for your OJ. We'll talk with University of Maryland plant virologist Anne Simon about ways to stop the citrus killer, and with science writer and journalist Maryn McKenna about why throwing antibiotics at the problem is probably not the solution. Related links: A Review of the Citrus Greening...