Throughout the past decade, valuable strides have been made in the studies of tiger health and recovery. A major finding in tiger health research occurred in 2001, when WCS field veterinarians and molecular scientists were first to genetically characterize and discover the presence of canine distemper virus (CDV) in the rare Amur tiger (also known […]Read more...
Throughout the past decade, valuable strides have been made in the studies of tiger health and recovery. A major finding in tiger health research occurred in 2001, when WCS field veterinarians and molecular scientists were first to genetically characterize and discover the presence of canine distemper virus (CDV) in the rare Amur tiger (also known as the Siberian tiger). Now WCS teams are expanding their studies to better understand how the disease is spread to tigers and might impact the larger population.
Canine distemper virus is the second most common cause of infectious disease death in domestic dogs, but also poses a significant threat to endangered and non-endangered wildlife around the globe. With the pressures of habitat loss, poaching, depletion of prey species, and CDV, WCS scientists and conservationists remain tireless in their efforts to combat these risk factors and protect and grow the remaining tiger population.
It is now understood that canine distemper virus tragically causes abnormal behaviors among tigers before eventually killing them. This is a distressing realization because there are likely no more than 3,500 tigers left in the wild, and all of the living subspecies are currently listed as Endangered by the International Union for the Conservation of Nature. Specifically, the Amur tiger is among the most endangered cat species on the planet, with only 400-500 individuals left across their range in the Russian Far East and China.
Since the discovery of distemper among Amur tigers, WCS has participated in further studies to delve into various transmission scenarios and impact. One study involves extracting genetic information from archived tiger tissue as well as from a variety of species in their territory. These samples are being tested and compared with the intent of pinpointing the most likely sources of infection among wild tigers. This testing is crucial in understanding the risk that the virus represents to wild tigers and local communities, and in developing methods to managing this risk, such as through the design of targeted oral vaccination programs.
WCS also participated in a study which extrapolates known CDV metrics to the larger tiger population. While the illness has been shown to lead to the deaths of individual tigers, its long-term impacts on tiger populations had never before been studied. The authors evaluated impacts on the Amur tiger population in Russia’s Sikhote-Alin Biosphere Zapovednik (SABZ), where tiger numbers declined from 38 individuals to 9 in the years 2007 to 2012. In 2009 and 2010, six adult tigers died or disappeared from the reserve, and CDV was confirmed in two dead tigers—leading scientists to believe that the disease likely played a role in the overall decline of the population. Using models, scientists were able to simulate the effects of the infection on isolated tiger populations of various sizes through various transmission scenarios. The study found that smaller populations of tigers are more vulnerable to extinction by CDV. Populations consisting of 25 individuals were 1.65 times more likely to decline in the next 50 years when the distemper virus was present. This was an alarming finding given that more than half the world’s tigers in 2010 were limited to populations of less than 25 individuals.
The results are alarming, but will allow teams to plan conservation strategies that address the finding and design new conservation approaches.
While canine distemper virus has presented an additional concern in tiger repopulation efforts, WCS has seen great success in the reintroduction of orphaned and rehabilitated tiger cubs back into the wild. In the spring of 2014, five young tigers were released into the wilderness of the Russian Far East as part of WCS’s effort to recolonize lost Amur habitat.
As studies increase our knowledge of the threats facing tigers and reintroduction efforts show success there continues to be greater hope for the overall survival of the species.
The phrase, ‘Eat your vitamins,’ applies to marine animals just like humans. Many vitamins are elusive in the ocean environment. University of Washington researchers used new tools to measure and track B-12 vitamins in the ocean. Once believed to be manufactured only by marine bacteria, the new results show that a whole different class of […]Read more...
The phrase, ‘Eat your vitamins,’ applies to marine animals just like humans. Many vitamins are elusive in the ocean environment.
University of Washington researchers used new tools to measure and track B-12 vitamins in the ocean. Once believed to be manufactured only by marine bacteria, the new results show that a whole different class of organism, archaea, can supply this essential vitamin. The results were presented Feb. 24 at the Ocean Sciences meeting in Honolulu.
“The dominant paradigm has been bacteria are out there, making B-12, but it turns out that one of the most common marine bacteria doesn’t make it,” said Anitra Ingalls, a UW associate professor of oceanography.
All marine animals, some marine bacteria and some tiny marine algae, or phytoplankton, need B-12, but only some microbes can produce the large, complex molecule. So like human vegetarians on land, marine organisms may be scouring for food that can help stave off vitamin deficiency.
“If only certain bacteria can make B vitamins, that can make B-12 a controlling factor in the environment. Is it present or not?” said Katherine Heal, a UW oceanography graduate student. “Studying the marine microbiome can help us understand what microbial communities could be supported where, and how that affects things like the ocean’s capacity to absorb atmospheric CO2.”
The UW team is the first to show that marine archaea, a single-celled organism that evolved totally separate from bacteria and all other living things, are making B-12. Relatives of these tiny critters are known for unusual behavior like living inside hot springs and underwater volcanoes.
The Seattle team managed to grow a common type of open-ocean archaea in the lab, no mean feat, and show that it not only makes enough B-12 to support its own growth but can supply some to the environment.
“It’s hard to quantify their contribution,” Ingalls said. “This is a first glimpse at their potential to contribute to this pool of vitamins.”
The analysis was done at a new UW marine chemistry center that does detailed analysis of proteins and other carbon-based chemicals in the ocean. The researchers used high-tech tools, including liquid chromatography and mass spectrometry, to identify the tiny amount of vitamins among all the dissolved matter and salt in the seawater. The UW method is unique in that it is the only one that can distinguish among the four forms of B-12 vitamins.
Field experiments involved sampling seawater in Hood Canal, near Seattle, and in the Pacific Ocean hundreds of miles offshore. The results showed that B-12 was present in small amounts in all water samples. Concentrations were low enough in some places that vitamin deficiency among tiny marine algae, or phytoplankton, is likely.
“Having a very small amount doesn’t mean there’s a very small supply,” Ingalls said. “Low concentrations can indicate something that’s highly desirable to marine organisms.”
The next step, researchers said, is to connect different microbes’ activity with the production of B vitamins, to see which organisms are responsible where, and to look at how ocean vitamins affect the type and amount of phytoplankton growing in the water.
Recent sequencing of the genomes of marine microbes has revealed genetic pathways in bacteria and archaea for creating B vitamins, but just because the gene is there doesn’t mean it’s being used. Marine microbes often adapt their behavior depending on the environment. In the case of vitamins, some bacteria make more B-12 if a phytoplankton is nearby, supporting their eventual food source.
Making a B-12 vitamin, which has a metal core and complex surrounding structure, involves 30-some steps.
“People think that’s why many organisms have lost it from their genomes,” Heal said. “It’s just too expensive to make it, and it’s easier to get it from food.”
The UW team hopes to learn which microbes are producing B-12 vitamins where, to better understand how the base of the marine food web works, how it might alter in a changing environment, how oceans might help regulate atmospheric carbon dioxide, and where marine animals could go to get a well-balanced diet.
“The public really has a very strange relationship to microorganisms,” Ingalls said. “People know they cause disease, so they want to kill them. But they’re also the only reason that we – or whales, fish or coral reefs – are alive.”
Collaborators are David Stahl, E. Virginia Armbrust, Allan Devol, Wei Qin and Laura Carlson at the UW, James Moffett at the University of Southern California and Willow Coyote, an undergraduate from Evergreen State College who will also present a poster at the meeting.