Issues; AVMA; Practice; Community

How big is Florida's python problem?

January was a bad month for giant-snake enthusiasts.

First, the U.S. Fish and Wildlife Service listed the Burmese python, yellow anaconda, and Northern and Southern African pythons as injurious invasive species under the Lacey Act, making it a federal crime to import the non-native snakes or transport them across state lines.

Nearly two weeks later, on Jan. 30, the Proceedings of the National Academy of Sciences published the first study documenting the ecologic impacts of feral Burmese pythons in Florida's Everglades National Park. Researchers found evidence suggesting python predation has caused dramatic declines in the numbers of raccoons, opossums, and other mammals in the park.

But, apart from a general recognition that feral pythons and other large constrictors have the potential to upset naive ecosystems, little else about the Sunshine State's invasive snake conundrum isn't in contention.

In dispute are how the giant reptiles first became established in South Florida, the number of Burmese pythons in the region, the scale of non-native snake predation on indigenous wildlife, the chances of pythons and other wild constrictors becoming established elsewhere in the United States, and the impacts of tougher restrictions on the trade and ownership of giant snakes.

When the USFWS announced its rules concerning constrictor species, Interior Secretary Salazar cited a 2009 U.S. Geological Survey analysis—“Giant constrictors: biological and management profiles and an establishment risk assessment for large species of pythons, anacondas, and the boa constrictor.”

The 302-page Constrictor Report, as it is known, classified Burmese pythons, Northern and Southern African pythons, boa constrictors, and yellow anacondas as high-risk invasive species for the following reasons: the snakes put large portions of the country at risk, constitute a significant ecologic threat, or are popular within the reptile trade. Medium-risk species are the reticulated python, DeSchauensee's anaconda, green anaconda, and Beni anaconda, the report stated.

The USGS risk analysis identified the pet trade as “the only probable pathway by which these species would become established in the United States.” The recent snake bans are meant to mitigate the invasive-constrictor threat by squeezing off channels through which a person can legally possess a giant snake. The other five constrictors in the report also face possible listing under the Lacey Act.

The Constrictor Report followed up on a 2008 paper in which USGS scientists used a climate-based distribution model to show a sizeable portion of the U.S. mainland is vulnerable to feral Burmese python habitation. Regions where the climate may be suitable to support python populations, according to the USGS study, include the Atlantic, Pacific, and Gulf coasts and range from Delaware to Oregon, including most of California, Texas, Oklahoma, Arkansas, Louisiana, Mississippi, Alabama, Florida, Georgia, North Carolina, and South Carolina. By 2100, the report said feral pythons may be able to expand their range to parts of Washington, D.C., and Colorado, Illinois, Indiana, Ohio, West Virginia, Pennsylvania, New Jersey, and New York.

Two subsequent studies challenge the premise that Florida's Burmese python can survive far from the snake's current subtropical home, however.

Using ecologic models that accounted for climatic extremes and averages, researchers at The City University of New York found the only suitable habitat for the python is in South Florida and far-south South Texas. Moreover, future climate models based on global warming forecasts indicate the python's current U.S. habitat and native range will actually decrease. A related study by scientists with the U.S. Department of Agriculture's National Wildlife Research Center found evidence suggesting Burmese pythons in Florida lack cold-weather survival instincts necessary to flourish elsewhere in the United States.

USGS scientists subsequently evaluated the methodology of the CUNY study. The models used to challenge the potential for python colonization in the United States may not identify all sites at risk of habitation, according to the paper they published in 2011. A more biologically realistic model less prone to statistical problems may reveal a larger geographic range where pythons could become established, the scientists concluded.

When the Senate was reviewing legislation in 2009 to designate constrictors as injurious animals, nine herpetologists and veterinarians wrote leading members of the Senate Committee on Environment and Public Works with concerns about the Constrictor Report. They questioned the USGS scientists' methods as well as the peer-review process the report underwent. The accuracy of the risk assessment model the report authors used was called into doubt; critics wrote the model resulted in a “gross overstatement” of the potential habitat for the snake species.

In their letter, critics noted “a pervasive bias” throughout the Constrictor Report. “There is an obvious effort to emphasize the size, fecundity, and dangers posed by each species; no chance is missed to speculate on negative scenarios. The report appears designed to promote the tenuous concept that invasive giant snakes are a national threat. However, throughout the report there is a preponderance of grammatical qualifiers that serve to weaken many, if not most, statements that are made,” the letter states.

The letter concludes with a request for the Senate committee to view the USGS analysis not as an authoritative scientific publication but as a report drafted with a predetermined policy in mind.

Dr. Elliott Jacobson, recently appointed professor emeritus at the University of Florida College of Veterinary Medicine, chairs the Association of Reptilian and Amphibian Veterinarians' Legislative and Animal Welfare Committee. One of three ARAV officials who signed the letter to the Senate committee, Dr. Jacobson isn't opposed to listing certain large constrictors as injurious wildlife—unless the science for doing so is flawed, which he believes to be the case.

“The perception is that certain politicians used the USGS report to justify their position without really understanding what was being presented in the report,” Dr. Jacobson explained.

Robert Reed, PhD, is a USGS invasive species scientist and herpetologist who co-authored both agency studies warning about the giant-snake threat. He's spent the past six years researching the brown tree snake, which, within four decades of its arrival in Guam, devastated much of the island's native wildlife. More recently, he's turned his attention to the Burmese python and is investigating the snakes' ecologic impact in South Florida and exploring ways of managing their numbers.


This Burmese python weighed 162 pounds and measured more than 15 feet long at the time of its capture in 2009. The giant constrictor was caught alive in the Everglades and had just eaten an American alligator that measured approximately 6 feet in length. (Photo by Mike Rochford/University of Florida)

Citation: American Journal of Veterinary Research 73, 5; 10.2460/ajvr.73.5.581

Dr. Reed knows what critics are saying about him. “I'm accused by the pet trade of pushing the ‘injurious’ listing to get loads of research dollars,” he said. “But I've never given any public opinion on the utility of this listing, and it doesn't result in any more research dollars whatsoever.”

He's equally dismissive of allegations he wants to criminalize snake ownership, as is his USGS colleague Gordon Rodda, who co-wrote both USGS invasive-snake studies.

“Gordon and I own or have owned giant constrictors, and we say so in the first chapter of the Constrictor Report. We think they're beautiful animals,” he explained. “To suggest we're anti–snake ownership is really silly on the face of it.”

“On the science issues,” Dr. Reed continued, “I'm happy to let the peer-reviewed papers speak for themselves. There's an increasing body of evidence to suggest that these snakes are a big problem in southern Florida and that there are several other (constrictor) species that have climates in their native range that suggest they could become established in the U.S.”

Burmese pythons have flourished in South Florida since the 1980s, yet no one could say with certainty how they were affecting the ecosystem. Then in late January, a study published in the Proceedings of the National Academy of Sciences made a correlation between severe mammal declines and the proliferation of pythons in Everglades National Park.

Dr. Reed was a co-author of the report, in which researchers state raccoons, rabbits, and opossums have almost entirely vanished from the southernmost regions of the Everglades, where pythons have been established the longest. Populations of raccoons in that part of the park dropped 99.3 percent, opossums 98.9 percent, and bobcats 87.5 percent. Marsh and cottontail rabbits and foxes were no longer seen at all, according to the study.

Data were gathered during repeated, systematic nighttime road surveys within the Everglades, with researchers counting live and roadkill animals. Surveys from 2003–2011 of nearly 39,000 miles of road were analyzed and compared with results of similar surveys performed along the same roadways in 1996 and 1997, before pythons were recognized as established in the park.

Researchers also surveyed ecologically similar areas north of the Everglades where pythons have not been discovered. In those areas, “mammal abundances” were similar to those reported in the park before pythons proliferated. At sites where pythons have only recently been documented, however, mammal populations were reduced, though not to the dramatic extent observed within the park where pythons are well-established.

“The magnitude of these (mammal) declines underscores the apparent incredible density of pythons in Everglades National Park and justifies the argument for more intensive investigation into their ecological effects as well as the development of effective control methods,” said lead study author Michael Dorcas, PhD, a professor in the Biology Department at Davidson College in North Carolina.

“Such severe declines in easily seen mammals bode poorly for the many species of conservation concern that are more difficult to sample but that may also be vulnerable to python predation,” added Dr. Dorcas, who co-wrote “Invasive pythons in the United States: Ecology of an introduced predator.” Published in 2007, the book suggested Burmese pythons could spread over much of the United States.

Shortly after the NAS Proceedings paper became available, The Huffington Post ran an article written by Frank Mazzotti, PhD, one of the study co-authors, in an attempt to clarify what the report does and doesn't say. The data do not show Burmese pythons caused the mammal declines, only that the snakes' occurrence is coincident with the decreases, wrote Dr. Mazzotti, an associate professor of wildlife ecology at the University of Florida.

“I liken what we did to a grand jury investigation,” he wrote. “We amassed the available evidence and asked if it was sufficient to demonstrate that a crime had occurred (mammal populations had declined) and to suggest that pythons could be responsible (they had motive, means, and opportunity). An indictment was handed down. That does not mean the pythons are guilty. It does mean we need to go to trial.”

The next step, according to Dr. Mazzotti, is to “design a study that evaluates the presence of the pythons with the absence of mammals in relation to differences and changes in habitat, hydrology, and other biological components.” The study should be a “high priority for funding,” he wrote, because it could go a long way toward identifying what's behind the mammal die-off in the Everglades.

“(W)hat happens if we are wrong and something else caused mammal populations to decline?” Dr. Mazzotti wrote. “Because if it is not pythons (and it might not be), something else is wrong in an ecosystem that we are spending billions of dollars to restore, and we need to know what that is.”

Kansas disease center's funding debated

Members of Kansas' congressional delegation say the nation needs the new animal disease center planned for their state.

Rep. Lynn Jenkins, whose district includes the planned site of the facility in Manhattan, Kan., was disappointed the president's proposed federal budget doesn't request any money for construction of the National Bio- and Agro-Defense Facility. But she expressed confidence the House of Representatives would see that the facility, which would replace the 60-year-old Plum Island Animal Disease Center in New York, is funded and built on the proposed site.

President Barack Obama's proposed fiscal year 2013 budget indicates Congress provided only $50 million of the $150 million the administration requested for construction of the facility during FY 2012, which ends Sept. 30. The 2013 proposal states that “is insufficient to begin construction on the project.” The recent proposal requested no appropriations for the facility but asked for $10 million toward research at Kansas State University on African swine fever and classical swine fever.

Kansas Sen. Pat Roberts said in a hearing for the Senate Agriculture Committee that the federal government has spent more than $100 million toward building the facility, and the state of Kansas has agreed to pay more than $200 million of the facility costs, according to a recording provided by his office. He noted that the building site has been cleared of structures.

Kansas Sen. Jerry Moran said in mid-February that $40 million in previously appropriated federal funds was available for utility work at the facility, which he sees as important to the nation's economic security.

The Department of Homeland Security estimated construction would cost between $525 million and $575 million, according to a 2009 solicitation for contractors at The facility is expected to encompass about 500,000 square feet and would be similar in size to a 400-bed hospital or a 1,600-student high school, DHS documents state.


Concept image of the National Bio- and Agro-Defense Facility in Manhattan, Kan. (Courtesy of Perkins+Will Inc.)

Citation: American Journal of Veterinary Research 73, 5; 10.2460/ajvr.73.5.581

A Homeland Security map indicates the department expects the facility will be built near KSU's Pat Roberts Hall, which is home to the existing Biosecurity Research Institute, and Mosier Hall, which houses the Veterinary Medical Teaching Hospital and the Department of Clinical Sciences in the College of Veterinary Medicine.

Officials with Kansas State University indicated they were working with their congressional delegation, and the proposed budget is one part of the appropriations process.

DHS Secretary Janet Napolitano told members of Congress in February that her department planned to convene a task force this year to assess whether and why such a facility should be constructed and review costs, safety, and alternative plans that could reduce costs and ensure safety, according to information provided by the DHS.

The administration's proposal documents indicate the $10 million requested for research at Kansas State would help the administration identify and prioritize future needs at the Biosecurity Research Institute and the NBAF.

DHS information indicates the Plum Island facility has biosafety levels 2 and 3 laboratories and that the Kansas facility would include BSL-2, BSL-3, and BSL-4 laboratories.

Education council recognized by national council on accreditation

The AVMA Council on Education, which accredits veterinary colleges, has received renewed recognition from the Council for Higher Education Accreditation.

Following a yearlong process of review, the CHEA board of directors granted continued recognition to the Council on Education on Jan. 23.

CHEA is an independent, nonprofit, nongovernmental organization that grants formal recognition to accreditation bodies for higher education that meet rigorous standards.

“In short, CHEA recognition provides assurance to the public and the profession that the AVMA Council on Education is fulfilling its charge in accordance with nationally established standards,” said Dr. David E. Granstrom, director of the AVMA Education and Research Division.

The CHEA Committee on Recognition found the council in full compliance with all criteria and recommended that it be recognized for up to 10 more years—the maximum length of recognition.

In its standards for recognition, CHEA requires accrediting bodies to meet the following criteria:

  • • Advances academic quality.

  • • Demonstrates accountability.

  • • Encourages, where appropriate, self-scrutiny and planning for change and for needed improvement.

  • • Employs appropriate and fair procedures in decision making.

  • • Demonstrates ongoing review of accreditation practices.

  • • Possesses sufficient resources.

The Council on Education has been continuously recognized by CHEA and its predecessors as well as the Department of Education for more than 50 years. The COE currently accredits 45 veterinary institutions—33 in the U.S. and Canada, and 12 in other countries.

CHEA scrutinizes the COE every 10 years and requires interim reports three and six years after recognition. DOE recognition must be renewed every five years.

Recognition by these two entities obligates the COE to follow strict guidelines designed to ensure that appropriate standards of accreditation have been developed and are being applied fairly and uniformly to all colleges seeking accreditation.

The COE submits voluntarily to CHEA review as part of its program of continuous improvement. It is a multistep process during which the COE had to demonstrate the quality of its activities and the value of those activities to higher education and the public interest.

The council's submission of eligibility documentation in September 2010 set the CHEA review in motion. The process continued with various reviews, and a CHEA observer made a site visit to the September 2011 COE meeting at AVMA headquarters in Schaumburg, Ill. The observer filed a report that identified no deficiencies. This past November, the CHEA Review Committee held a public meeting to review the evidence and hear testimony from the council chair and senior staff support. In January, the CHEA board approved the Review Committee's decision to continue recognizing the COE.

Accreditation task force members announced

The AVMA created a Task Force on Foreign Veterinary School Accreditation this past August to evaluate the following issues, given the current environment projected over 10 years, and to prepare a written informational report, without prejudice, to the Executive Board:

  • • The impact of foreign veterinary school accreditation on the U.S. veterinary profession, and the quality of standards for the U.S. veterinary profession.

  • • The impact of not requiring certification by the Educational Commission for Foreign Veterinary Graduates or the Program for the Assessment of Veterinary Education Equivalence for graduates of AVMA Council on Education-accredited foreign schools.

  • • How foreign veterinary school accreditation serves the needs and interests of the public.

  • • How foreign veterinary school accreditation serves the needs and interests of AVMA members.

  • • The existence of any international pressure on the AVMA COE to accredit foreign veterinary schools.

  • • The logistic resources required to accredit foreign veterinary schools.

In February, the AVMA announced the task force members who had been appointed. They are as follows: Dr. James R. Coffman, Manhattan, Kan., chair; Dr. Mimi Arighi, West Lafayette, Ind.; Dr. Philippe J. Baneux, Winnetka, Ill.; Dr. Eric M. Bregman, New York; Dr. Susan B. Chadima, Topsham, Maine; Dr. Orlando Garza, El Paso, Texas; Dr. Peter W. Hellyer, Fort Collins, Colo.; Dr. Anthony M. Miele, New York; Dr. Mark Nunez, Van Nuys, Calif.; Jason Stanhill, Fort Collins, Colo.; and Dr. Caroline J. Zeiss, New Haven, Conn.

Study examining swine veterinarians' MRSA risk

Researchers in Minnesota hope to improve understanding of the frequency, duration, and risks of methicillin-resistant Staphylococcus aureus colonization and infection among swine veterinarians.

Dr. Peter Davies, a professor of swine health and production at the University of Minnesota and lead researcher on the project, said that in previous studies, high percentages of nasal swab specimens taken from veterinarians have been positive for methicillin-resistant S aureus. The present study is needed to provide missing information on the implications of those positive nasal culture results, help determine whether positive culture results reflect colonization or transient contamination, and quantify health risks for veterinarians, he said.

The project is being conducted through the Upper Midwest Agricultural Safety and Health Center at the University of Minnesota; the center is funded by the National Institute for Occupational Safety and Health of the Centers for Disease Control and Prevention. The center is receiving about $1.6 million in funding this year, and about $160,000 of the year's budget is going toward the MRSA project, a CDC spokeswoman said.


A veterinarian and a veterinary student at Oklahoma State University demonstrate safe use of a laser for surgery. Safety precautions include use of a smoke evacuator, eyewear specific for the laser wavelength, and laser-safe surgical masks. (Courtesy of Dr. Kenneth E. Bartels)

Citation: American Journal of Veterinary Research 73, 5; 10.2460/ajvr.73.5.581

The study authors intend to examine S aureus colonization patterns in 70 U.S. swine veterinarians over 18 months, determine the incidence of occupation-related skin and soft-tissue infections, assess protective measures used by swine veterinarians, and quantify the associations between exposure to pigs and the risk that swine veterinarians will be colonized or infected with MRSA or methicillin-susceptible S aureus strains, according to information from Dr. Davies.

The S aureus strains found in swine veterinarians will be typed to determine whether they are associated with livestock, and the project will include a concurrent survey of occupational hazards and risk-reduction practices among swine veterinarians, according to information from the Upper Midwest Agricultural Safety and Health Center.

Laser guidelines encompass veterinarians

Laser safety in veterinary medicine is now an integral part of the American National Standards Institute's Z136.3 guidelines for the safe use of lasers in health care.

In 2005, an appendix was added to that year's edition of the ANSI Z136.3 guidelines, for information only, on the safe use of lasers in veterinary medicine. The 2011 edition, newly available, retains the appendix but also incorporates veterinary offices and animal patients throughout the body of the document.

“These are guidelines but now carry a bit more weight on how we use lasers in veterinary medicine,” said Dr. Kenneth E. Bartels, AVMA representative to the Z136.3 subcommittee and a professor of laser surgery at Oklahoma State University Center for Veterinary Health Sciences.

The federal Occupational Safety and Health Administration and state regulatory agencies refer to the Z136.3 standard, Dr. Bartels noted.

More than a decade ago, the AVMA asked Dr. Bartels to become a liaison to the Z136.3 subcommittee to ensure that a veterinarian had input into guidelines applicable to the profession. He said some members of the subcommittee did not believe that veterinary medicine should be part of the standard, because the patients are not human.

“However, the vet as well as the tech involved in the laser technique—as well as our patients—warranted safe use of the technology,” Dr. Bartels said.

Basic precautions for safe use of lasers in health care include posting signage and using a smoke evacuator and appropriate eyewear, Dr. Bartels said.

The Z136.3 guidelines are available for purchase from the Laser Institute of America at Members of the AVMA who reference “AVMA” with their orders will receive the LIA member price of $130. The regular price is $150.


The Conference of Research Workers in Animal Diseases misidentified the winner of an NC-1041 Enteric Diseases (North Central Committee for Research on Enteric Diseases of Swine and Cattle) student award. The incorrect name ran in “CRWAD dedicated to Simmons,” published in the April 2012 AJVR News section. Hyeun Bum Kim of the University of Minnesota took top prize in the award's oral category.

  • View in gallery

    This Burmese python weighed 162 pounds and measured more than 15 feet long at the time of its capture in 2009. The giant constrictor was caught alive in the Everglades and had just eaten an American alligator that measured approximately 6 feet in length. (Photo by Mike Rochford/University of Florida)

  • View in gallery

    Concept image of the National Bio- and Agro-Defense Facility in Manhattan, Kan. (Courtesy of Perkins+Will Inc.)

  • View in gallery

    A veterinarian and a veterinary student at Oklahoma State University demonstrate safe use of a laser for surgery. Safety precautions include use of a smoke evacuator, eyewear specific for the laser wavelength, and laser-safe surgical masks. (Courtesy of Dr. Kenneth E. Bartels)