Category Archives: Epidemiology

New Salmonella Dublin test for milk and cattle available for first time in US

Salmonella can cause serious disease on cattle farms, killing calves, causing cows to abort, contaminating raw milk, and harming humans along the way. While the cattle-adapted strain Salmonella Dublin creeps into the Northeastern US, veterinarians and farmers struggle to catch the bacteria in time to protect livestock because these bacteria often hide dormant in carrier animals, making the strain particularly hard to diagnose.

For the first time in the US, a more useful test for Salmonella Dublin is now available exclusively at the Cornell University College of Veterinary Medicine’s Animal Health Diagnostic Center (AHDC). Cheaper, quicker, safer, and more sensitive, the test detects antibodies rather than bacteria. Traditional bacteriological tests could only identify S. Dublin organisms in sick or deceased animals, missing up to 85% of infections in carrier cattle. The new test reveals carriers, helping farmers and veterinarians monitor infection spread over time and track the impact of control measures in ways that were previously impossible.

Dairy-cows-Pavement“We’re very concerned about this disease spreading east because it could severely harm animal and human health, as well as the livelihoods of dairies in the region,” said Dr. Belinda Thompson, senior extension associate at the AHDC. “Salmonella Dublin is already common west of the Mississippi River, but it’s only recently being recognized in the Northeastern US. We want to be pro-active now to keep it out of our farms.”

In recent years the AHDC has dealt with several high-morbidity and high-mortality outbreaks of Salmonella Dublin in New York and other states. To address the problem before it grows further, Dr. Bettina Wagner, director of the Serology and Immunology Section of the AHDC laboratory, secured the nation’s first USDA permit to import and use the enhanced test.

While Salmonella Dublin usually doesn’t make adults cows very sick, it can wreak havoc on young and unborn calves, particularly in populations like those in the East Coast that haven’t been exposed. Its resistance to many common antibiotics severely limits treatment options and, to make matters even worse, it often presents as respiratory disease, throwing off track veterinarians trained to recognize diarrhea as salmonella’s telltale sign.

“Infected calves often look fine the day before a sudden rapid onset, the next day they look depressed, and the next day they die,” said Dr. Paul Virkler, senior extension associate at the AHDC. “Veterinarians often think it’s something else-. We’ve seen newly infected herds in which every single calf in a particular age group dies. We’re trying to keep this from getting to baby calves, the life and future of a farm, and the animals most at risk.”

People working with cattle are also at risk. All Salmonella strains affect most vertebrates and can jump between species. Even carriers that don’t seem sick can shed bacteria, and people, companion animals, and other livestock can pick up the infection through contact with any bodily excretion.

“People have died drinking raw milk with Salmonella Dublin,” said Virkler. “It’s one of the bad players in raw milk. Pasteurizing milk will kill the bacteria.”
Prior to the new test’s release, testing had to be done animal by animal. The new antibody test can use milk samples straight from bulk milk tanks to find whether a herd has been exposed. It can also work with blood samples and diagnose individuals, helping keep unexposed herds infection-free by removing infected animals and pre-screening new animals farmers are considering buying.

“Herd managers can take preventative measures and help control the infection’s spread by isolating sick calves, pasteurizing milk, managing cattle movement, and improving hygiene,” said Thompson. “But to see if any of this is working, they need a tool to monitor success. We didn’t have that until now. This test will let us learn about the prevalence of Salmonella Dublin on the East Coast and hopefully nip it in the bud.”
cows in field

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http://vet.cornell.edu/news/Dublin.cfm

Media Hits:

Cornell Chronicle

http://www.news.cornell.edu/stories/Oct12/SalmonellaDublin.html

Meat Trade News Daily

http://www.meattradenewsdaily.co.uk/news/291112/usa___a_lack_of_understanding_over_salmonella_.aspx

MyScience

http://www.myscience.us/wire/cornell_offers_only_u_s_salmonella_dublin_test_for_cattle-2012-cornell

The Post Standard: Syracuse.com

http://blog.syracuse.com/farms/2012/11/better_test_for_cattle_disease.html

Phys.org

http://phys.org/news/2012-11-cornell-salmonella-dublin-cattle.html

Drovers CattleNetwork.com

http://www.cattlenetwork.com/cattle-news/Cornell-offers-only-US-salmonella-dublin-test-for-cattle-176821551.html?ref=551

Bovine Veterinarian Online

http://www.bovinevetonline.com/news/industry/Cornell-offers-only-US-salmonella-dublin-test-for-cattle-176821551.html

USAgNet

http://www.usagnet.com/story-national.php?Id=2486&yr=2012

Dairy Herd Network

http://www.dairyherd.com/dairy-news/latest/Cornell-offers-only-US-salmonella-dublin-test-for-cattle-176821551.html

Food Safety News

http://www.foodsafetynews.com/2012/11/cornells-new-test-spots-salmonella-in-cattle/

Ithaca Journal

http://www.theithacajournal.com/article/20121111/NEWS01/311110027/Cornell-test-detects-salmonella-cattle?odyssey=mod|newswell|text|FRONTPAGE|p

Before It’s News

http://beforeitsnews.com/food-and-farming/2012/11/cornells-new-test-spots-salmonella-in-cattle-2446024.html

Healthy Cooking News

http://healthycookingnews.blogspot.com/2012/11/cornells-new-test-spots-salmonella-in.html

Beef Cattle News

http://savant7.com/beefcattlenews/

Stop Foodborne Illness

http://www.stopfoodborneillness.org/content/cornell%E2%80%99s-new-test-spots-salmonella-cattle

MeatingPlace

http://webcache.googleusercontent.com/search?q=cache:lnLu6SjDDeMJ:www.meatingplace.com/Industry/News/Details/37578+&cd=2&hl=en&ct=clnk&gl=us

Highbeam Business

http://business.highbeam.com/409224/article-1G1-310739927/cornell-offers-new-salmonella-test-cattle

CABI.org VetMed Resource

http://www.cabi.org/VetMedBeta/news/22617

The Meat Site

http://www.themeatsite.com/meatnews/19365/cornell-offers-us-salmonella-dublin-test-for-cattle

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Conservation in action

First Indonesian to receive major fellowship will help save world’s rarest rhinoceroses

Deep in the Indonesian rainforest on the island of Java roam the last of earth’s most critically endangered large mammal species: the Javan rhinoceros. Once Asia’s most widespread rhinoceroses, these secretive forest-dwellers disappeared altogether from the continent’s mainland in October 2011, when the last individual was found dead in Vietnam with its horn chopped off by poachers. A single population of just 40 rhinoceroses survives in the western half of Java’s Ujung Kulon National Park, cramped into a corner of the island that has reached its carrying capacity.

The Indonesian government recently endorsed a daring plan to expand the range of their emblem species by establishing a second population with more room to grow. Yet a major concern remains. The plan involves moving some rhinoceroses from the isolated westernmost tip of Java to the eastern side of the park—an area surrounded by 19 agricultural villages whose inhabitants rely on water buffalo to work their rice paddies. No fences limit the wanderings of these loosely managed buffalo, which regularly pass into the park and could spread diseases that would quickly decimate the rhino’s population.

Cornell postdoc Dr. Kurnia Khairani has received a Fellowship Training Grant from the Morris Animal Foundation to address this problem. With the help of faculty and students at the College of Veterinary Medicine, Khairani is combining fieldwork in Indonesia with labwork and training at Cornell to improve the health and outlook of Javan rhinoceroses. It is the first time an Indonesian has received this prestigious award, and the first time a Cornell fellow will be trained in conservation medicine.

“Of the five rhinoceros species the Javan is the rarest, and Khairani’s work is critical to its future,” said Dr. Robin Radcliffe, director of the Cornell Conservation Medicine Program, one of the world’s foremost experts working in rhino conservation. Radcliffe oversees the project and is excited by its possibilities. “Khairani herself is a major investment for conservation efforts in this region: she will take her Cornell training back to Indonesia and become a decision-maker in her own country. Cornell is involved in real-world conservation, training people who will use what they learn here to tackle new problems in the race to preserve biodiversity.”

A postdoc in the laboratory of immunologist Dr. Julia Fellipe, Khairani will work under the joint mentorship of Fellipe and Radcliffe. Additional mentorship from epidemiologist Dr. Daryl Nydam and microbiologist Dr. Pat McDonough will round out Khairani’s skills.

Conducting a preliminary health survey of village buffalo, Khairani found several diseases of concern to rhinoceroses, including blood parasites, salmonellosis, and leptospirosis. With highly infectious diseases such as SARS, West Nile Virus, and Avian Influenza making worldwide headlines for crossing species barriers and ecosystems, it is critical to get this historic move of the rarest rhinoceros right the first time. Khairani’s ongoing survey will focus on hemorrhagic septicemia, a bacterial disease linked to four recorded die-offs of Javan rhinoceroses in the region. Khairani will determine the prevalence, distribution, and risk of contracting septicemia faced by the buffalo population; conduct questionnaire-based interviews with buffalo owners to determine management factors that might contribute to the regional epidemiology of the disease; and propose possible interventions.

The project also involves outreach, educating local public health officers and villagers on septicemia diagnosis and management through hands-on training. It has also opened doors for Cornell veterinary students to gain valuable hands-on international experience, and several have already conducted internships in Indonesia with Khairani through Cornell’s Conservation Medicine Program with funding by Expanding Horizons.


“Knowledge of the region’s diseases will help veterinary officers improve the health of buffalo, a resource crucial to the region’s economic vitality,” said Khairani. “Healthier buffalo will enhance the well-being of local villagers while reducing their impact on the park. Improving our understanding of animal health in the area will help reduce the risk of disease transmission from livestock to rhinoceroses. This is essential to establishing a second habitat and population of the rare Javan rhinoceros, a crown jewel of Indonesia’s amazing biodiversity.”

‘Scopes Magazine
February 2012

Reverse genetics better vaccines

Cornell-Israel collaboration works backwards to fight virus threatening livestock trade worldwide

European livestock beware: bluetongue virus is coming your way, and it’s deadlier than ever. Once limited to warmer climes, the insect-borne virus’s new highly pathogenic strain has been spreading northward since 2006, reaching farther into Europe than ever before. Bluetongue’s rise threatens ruminants and the industries depending on them. Sheep and deer suffer most, developing dangerously high fevers, swollen mouths, and occasionally the disease’s signature blue tongue. Most infected sheep and deer die; other ruminants (cattle, goats, camels, buffalo, and antelopes) show milder symptoms but can carry the disease, further enabling its spread.

Illnesses, deaths, and international trade restrictions due to bluetongue have cost the world economy billions, including the United States, whose more benign strains still hinder livestock-related exports to bluetongue-free countries. Vaccines work weakly at best: with 25 separate strains each needing yearly updates, the quickly-evolving bluetongue virus seems to defy defense.

In the arms race between virus and victim, human knowledge is catching up. Dr. John Parker, virologist at Cornell University College of Veterinary Medicine’s Baker Institute for Animal Health, has joined Israeli microbiologist Dr. Marcelo Ehrlich of the University of Tel Aviv to learn what makes bluetongue tick, unlocking the inner workings of its deadliest strain with discoveries that could help in designing a lasting universal vaccine.

“No one thought bluetongue would spread this far, and with current vaccines even the most watchful countries can’t protect themselves from it,” said Parker. “Insects carrying bluetongue don’t respect national borders, and climate change has let them expand their range. Meanwhile this new strain is especially virulent: good at bursting through cells to infect new ones. If we can learn how bluetongue kills cells and why this strain is so good at it, we may be able to better control its spread.”

When bluetongue invades a cell it creates a protein called NS3, reproduces, and eventually bursts through the cell. All strains produce NS3, but the more virulent strains produce an altered form. When experiments in Israel suggested NS3 helps degrade cells so the virus can escape, Ehrlich contacted Parker, a former collaborator, who studies cell death.

The pair has created a novel plasmid-based system to discover exactly what NS3 does using reverse genetics. While standard “forward” genetics start with a trait then look for the genes influencing it, recently developed “reverse” genetics systems manipulate specific genes to look for their effects. Parker and Ehrlich are making mutant bluetongue viruses that alter NS3 to see what it does in a cell.

“Reverse genetics has become the gold standard for doing molecular virology,” said Parker. “It’s particularly useful for studying specific proteins. But until recently it was very difficult to develop these systems for reoviruses, the family to which bluetongue belongs.”

In 2006 one of Parker’s collaborators created a new reverse genetics system that uses plasmids, easily copied pieces of bacterial DNA, to insert viral mutants directly into cells, skipping steps that once impeded the study of reoviruses.

“The majority of Cornell’s microbiology labs do this every day: they take plasmid DNA, mutate it, and study the effect on a protein,” said Parker. “It’s much more convenient and makes transferring genetic material between labs easier, enabling better collaboration. In Israel, where virulent bluetongue is common, Marcelo will conduct experiments that for biosecurity reasons could never be conducted in the US, where strains are relatively benign.”

The researchers took an unusual route in constructing the mutant viruses they will study: hiring a company to synthesize them from scratch.

“These days you can make a pathogen by putting in an order,” said Parker. “It was first done for Polio virus, and more and more researchers are taking this approach. It’s cheaper and faster than paying grad students to spend months cloning genes. People used to learn PCR—nowadays my lab staff learn how to place an order, making sure the DNA sequence they ask for is right.”

“Viruses are often seen as mysterious and dangerous things that are hard to control. There’s some truth to that, but we are making significant progress in our abilities to manipulate viruses in ways that help us understand them better in order to develop better vaccines and treatments.”

Their work is supported by the US-Israel Binational Agricultural Research Development (BARD) Fund, which funds collaborative research to solve agricultural problems.

File:Map of molecular epidemiology of bluetongue virus in Europe.gif

The molecular epidemiology of bluetongue virus (BTV) since 1998: routes of introduction of different serotypes and individual virus strains. 

Map Source

‘Scopes Magazine
February 2012

Student’s Fulbright project tackles potential epidemics in Trinidad and Tobago

pFrom the stray-strewn streets of Trinidad and Tobago to cow-covered pastures of rural New York dairy farms, Miguella Paula-Ann Mark-Carew has journeyed far in her quest to understand and combat disease epidemics across the world. Ever since she came to Cornell’s College of Veterinary Medicine through a veterinary summer program when she was 17, Mark-Carew wanted to return as a full-time student. While attending Dartmouth College, she spent two respective summers  conducting epidemiological research with Drs. Paul Bowser and Ted Clarke, and her positive experiences with Cornell faculty further sealed her aspiration. In 2007 she came to Cornell’s College of Veterinary Medicine as a doctoral student in the field of comparative biomedical sciences.

An aspiring epidemiologist, Mark-Carew studies Giardia parasite infections at the group and population levels to help understand and control potential epidemics. Giardia protozoa infect the small intestine of humans and other animals, causing stomach pain, diarrhea, bloating, fever, nausea, and vomiting for two to four weeks. It commonly spreads via water contaminated by raw sewage or animal wastes. It can also spread between individuals, quickly putting populations at risk. Mark-Carew’s Giardia studies took her from the New York Watershed to the islands of Trinidad and Tobago to study the parasite’s prevalence and genetic makeup in dairy cattle and other mammals.

tr
After receiving a Fulbright grant funding an independent epidemiological project, Mark-Carew returned to the Caribbean state of Trinidad and Tobago to take on a growing health concern facing her family’s homeland. Her Fulbright project involves efforts to quantify, manage, and control the population of thousands of stray and free-roaming dogs in streets across the country. These dogs can carry Giardia and other diseases humans can catch, posing a serious potential public health risk, according to Mark-Carew. Beyond its medical and epidemiological significance, the project involves sociological surveys with political potential. Mark-Carew interviews residents and tourists about their perspectives on several concerns, including stray dog issues, testing to identify parasites, and the value of continuing her efforts to count the number of strays, all with the hope of inspiring policy changes to address the stray problem.

“I adopted three puppies when they were a month old from an active dog abandonment site,” Mark-Carew mentioned. “One is with me now in Ithaca, and the other two are scheduled to fly home with me after my visit this coming January. I literally brought my work home with me!”

 

Other Projects

Mark-Carew has also been involved with a project called “Caring Collars Loving Leashes” that was started by her mother, Marlene Mark, to promote the human-animal bond.

“We encourage owners to walk their dogs and obtain ID tags for free collars we give out so they can find their dogs if they get lost,” said Mark-Carew. “Over 150 collar and leash sets were split between the two branches of the Trinidad and Tobago Society for the Prevention of Cruelty to Animals (TTSPCA). We’d like for it to be an annual campaign during May, National Pet Month in the US.”

 

Inspired by a talk Mark-Carew gave at Cornell about her project, five Cornell students have visited Trinidad and Tobago to lend a hand. Sophie Tilitz, a rising freshman undergraduate interested in animal science, helped for six weeks from February to April 2011. In January 2011, second-year veterinary student Jasmine Bruno and third-year students Sarrah Kaye, Erin Lashnits, and Sarah Dumas spent two weeks on the islands with Mark-Carew collecting parasite samples from dogs, cattle, and water buffalo, processing samples in the lab, counting roaming dogs in the streets, and volunteering in an intensive marathon spaying and neutering event.

(Read more about their adventures.)

 

Future Plans

Mark-Carew hopes her career will allow her to assist the World Health Organization or similar entities to navigate an increasingly globalized world through which pathogens can spread quicker than ever before. She aims to understand how diseases differ across the world and species and hopes to work on projects concerning public health and animal health, particularly dealing with waterborne diseases in developing countries.

“I plan to return to Trinidad and Tobago during January 2012 break and Summer 2012,” said Mark-Carew. “This project means a lot to me and I plan to devote several years to seeing that something is done to control roaming dogs and promote responsible dog ownership in Trinidad and Tobago. I am looking for additional Cornell students to help with the roaming dog assessment project, and can be reached at mpm26@cornell.edu.”

 

For more on Mark-Carew’s Fulbright project, visit her blog: http://halfbrightfulbright.blogspot.com/

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http://www.vet.cornell.edu/news/carew.cfm