CDC Doing the American Bird Conservancy’s Bidding?

Representatives of the Centers for Disease Control and Prevention sign on to the American Bird Conservancy’s witch-hunt against free-roaming cats, misrepresenting the relevant science to support their claim that “rabies transmission via feral cats is a particular concern.”

“Feral cat populations,” argue the authors of a recently published paper, “must be reduced and eliminated to manage the public health risk of rabies transmission.” [1] Their solution? “Traditional animal control policies [that] have stressed stray animal control and removal.”

It’s no surprise, given the American Bird Conservancy’s contribution (president George Fenwick is among the paper’s seven co-authors, and Steve Holmer, Bird Conservation Alliance director, is thanked in the acknowledgments for his “review and input during the writing of the manuscript”) that the article provides no evidence whatsoever of such policies and practices reducing the risk of rabies posed by free-roaming cats.

Witch-hunts, after all, have little use for evidence.

But the Centers for Disease Control and Prevention and U.S. Department of Agriculture, representatives of which make up the paper’s other six co-authors,* rely on solid evidence to develop sound public policy.**

Don’t they?

To borrow a line from Ernest HemingwayIsn’t it pretty to think so?

Pretty, as well, to think that a journal dedicated to “advanc[ing] the scientific knowledge of the sources, transmission, prevention, and control of zoonoses” would steer clear of the kind of agenda-driven pseudoscience that’s become ABC’s trademark (and, according to some, their bread and butter). But the editors at Zoonoses and Public Health showed their true colors a year ago, when they published*** a similar submission by TNR opponents Rick Gerhold and David Jessup—who resorted to the usual mischaracterizations and cherry-picking in an effort to build a case around their central thesis: “free-roaming cat populations… [are] a significant public health threat.” [2]

It’s become an all-too-familiar occurrence: scaremongering dressed up as science.

And so it goes with “Rabies Prevention and Management of Cats in the Context of Trap-Neuter-Vaccinate-Release Programmes.” Among the authors’ more egregious sins…

The Kitchen Sink Approach

Given the title of both the paper and the journal, it’s odd how much real estate the authors devote to anti-TNR rhetoric that has little or nothing to do with rabies. Or facts, for that matter. Odd, perhaps, but not unexpected—try everything and see what sticks, right? Among the “highlights” are the following:

  • Echoing the unsubstantiated claims made earlier this year by researchers at the Smithsonian Conservation Biology Institute and U.S. Fish and Wildlife Service, for example, Allison Roebling and her co-authors argue that “exotic feral cats can have profound ecological effects on native species.” [1] Well, maybe argue is too strong a word. After all, the “evidence” provided (e.g., Cole Hawkins’ illusion of population impacts, Phil Baker’s inflated predation figures, etc.) is an immediate red flag to anybody familiar with the topic.
  • “A study of 103 local colonies in Rome, Italy,” explain Roebling et al., “found that while half of the colonies reported population decreases, virtually the same number were stable or showed increases in spite of an active sterilization campaign and the adoption of most of the kittens being born in colonies.” [1] Well, that’s one way to put it, I suppose. Another way to put it is that the caretakers observed a 22 percent decrease overall in the number of cats through TNR—despite a 21 percent rate of “cat immigration.” [3]
  • “One recent study, which modelled costs and benefits for TNVR as compared to trap and euthanize programmes,” write Roebling et al., “found that in all scenarios, trap and euthanize programmes were less expensive to conduct and had a higher economic benefit.” [1] As I discussed in December, Cheryl Lohr’s “study” is riddled with enough invalid assumptions (e.g., a 30,000-cat “super colony,” the value of a wedge-tail shearwater as much as $15,000 while a cat is worth $0, etc.) to render her model meaningless (if not downright offensive, in light of the USDA funding involved).

    As Walter Lamb argued in a recent issue of Ecological Economics, “The desire to create favorable economic valuations for things that we know to be ecologically important is understandable, but bypassing accepted scientific and economic principles in order to do so sets a dangerous precedent and risks many unintended consequences.” [4]

  • “The feline immunosuppressive diseases (i.e., FIV and FeLV) are especially important because they may predispose infected cats to developing additional viral, bacterial or parasitic diseases that can be passed to humans or owned cats,” argue Roebling and her colleagues. “Many of these diseases are prevalent at higher levels in feral cats compared with the owned pet population because outdoor access poses the greatest risk of infection.” [1] Ironically, the work they cite to make this last point is perhaps some of the strongest evidence in favor of TNR. As veterinarian Susan Little, “one of only four board-certified feline specialists in Canada,” according to the Bytown Cat Hospital website, explains in her 2011 paper, “seroprevalence of FIV was highest in urban stray cats (23 percent) and lower in client-owned cats (5.9 percent) and in a feral cat colony (5 percent).” [5, emphasis mine]

    Little’s findings were very much in line with an earlier study (overlooked or ignored by Roebling et al.) of 1,876 colony cats that revealed an FeLV prevalence of 4.3 percent and an FIV seroprevalence of 3.5 percent rate, “similar to infection rates reported for owned cats.” [6]

Even setting aside the factual inaccuracies—as the authors of “Rabies Prevention and Management of Cats” seem to have done—what any of this is doing in a paper ostensibly about rabies remains a mystery.

Will the Real CDC Please Stand Up?

When Roebling and her colleagues do address the issues of rabies, the rigor improves substantially, right?

More pretty thoughts, I’m afraid.

To begin with, the authors contrast the number of rabies cases in cats (303 in 2010) to those in dogs (69 in 2010), arguing that “the dramatic decline in dog rabies from over 8,000 cases a year to fewer than a hundred was accomplished through policies that promote mass vaccination coverage and control of strays.” [1] Yet, as two of the authors—Charles Rupprecht, chief of the CDC’s Rabies Program, and Jesse Blanton, epidemiologist for the CDC—have explained in a report referring to the very same 2010 data:

“Because most animals submitted for testing are selected on the basis of abnormal behavior or signs of illness, percentages presented in this report are not representative of the incidence of rabies in the general population. In addition, because of difference in protocols and submission rates among species and states, comparisons of the percentages of rabid animals between species or states are inappropriate.” [7, emphasis mine]

Inappropriate or not, Roebling et al. go on to argue that “less emphasis on control and removal of stray cats is likely the cause of increased numbers of rabid cats compared with dogs.” [1] But the report they cite as support—to which Rupprecht contributed—provides a more complete picture.

“During 2000–2006, more cats than dogs were reported rabid in the United States. The majority of these cases were associated with the epizootic of rabies among raccoons in the eastern United States. The large number of rabid cats compared with other domestic animals might be attributed to a lower vaccination rate among cats because of less stringent cat vaccination laws; fewer confinement or leash laws; and the nocturnal activity patterns of cats placing them at greater risk for exposure to infected raccoons, skunks, foxes, and bats.” [8]

As the CDC notes on its website, “the number of rabid cats outnumbered the number of rabid dogs” in the U.S. for the first time in 1981, [9] just about the time the number of cases in skunks spiked, followed by a massive, sustained increase in raccoon cases (graph).

Under the circumstances, then, an increase in the “control and removal of stray cats” sufficient to bring the rabies cases down to a level acceptable to the authors (whatever that might be) would likely be cost-prohibitive—and no doubt unacceptable to the public.

(Interestingly, Rupprecht spoke at the recent Alliance for Contraception in Cats & Dogs conference—and never mentioned cats once during either his presentation or his panel’s Q&A session. He did, however, refer numerous times to rabies in dogs.)

The (Very Focused) Search for Rabies

While there’s no doubt that post-exposure prophylaxis (PEP) is expensive, the claim made by Roebling and her colleagues that “biologics alone cost in excess of $2,000” [1] doesn’t correspond to information on the CDC’s own website, where it’s suggested that “a course of rabies immune globulin and five doses of vaccine given over a four-week period typically exceeds $1,000.” [10] And a three-year (April 1999–March 2002) study of five upstate New York counties found that “the average terrestrial rabies-associated PEP cost was $941.06, with a range of $440.21 to $1,884.97 per county.” [11] “The average per capita cost for terrestrial rabies including PEPs, specimen preparation/shipment, and pet vaccination clinics was $0.32, with a range of $0.10 to $0.77.”

That’s right: less than a buck per resident. (Or $1.08 in 2013 dollars.)

Even so, Roebling et al. would have us believe that whatever the cost, cats are largely to blame. “No national reporting system exists to quantify the proportion of PEP attributable to cat exposures,” note the authors, “but estimates indicate that 16 percent of PEP administration in the United States is likely due to cats and may account for the majority of PEP administration in some areas.” A review of the paper cited, however, suggests that this estimate is not, contrary to what we’re led to believe, a reflection of nationwide PEP use.

As Kira Christian and her co-authors—including both Rupprecht and Blanton—explain, the estimate was derived from results of a questionnaire distributed “to known health department contacts working in rabies-related assignments in each of the 50 states, Puerto Rico, Washington, DC, and New York City.” [12] But only 12 of the 17 respondents who “were able to calculate an estimated average annual rate of PEP administration for the major rabies reservoirs present in each state” (AK, CA, CO, FL, HI, KY, ME, MD, NY, NYC, OH, OK, SC, TN, TX, VT, and WA) were also “able to provide an estimate of the number of PEP by animal type.” Unfortunately, Christian et al. don’t specify which 12 provided this level of detail.

In any event, extrapolating from just 12 respondents to produce a nationwide estimate—in light of the well-documented state-to-state variation—seems completely inappropriate.

And yet, Roebling and her colleagues go further: “Most striking, a study in Montgomery County, Virginia, attributed 63 percent of PEP recommendations to stray cat exposures compared with only 8 percent for wild animal contact.”

“In this community, the high rate of PEP due to cats resulted in part from the lack of a county animal shelter facility for cats, illustrating the need for removal of feral and stray cats as a means of rabies control and PEP reduction.” [1]

Obviously many communities do have shelters—many of which routinely kill stray and feral cats. Yet the authors provide no examples of such communities reducing PEP. (Where are all the “success stories”?) And their focus on the raccoon rabies hot spots is a move reminiscent of Gerhold and Jessup, who cherry-picked their way to a claim that “cat exposures account for approximately one-third of all PEP recipients.” [13]

A more representative perspective is provided by a study of “11 geographically diverse university-affiliated, urban emergency departments” (see map in my October 12, 2012 post), which found that of 2,030 patients enrolled, 1,635 exposures (81 percent) were attributed to dogs, and 268 (13 percent) to cats. [14] (This same study found that PEP was applied unnecessarily in about 40 percent of the cases documented. Other research has documented similar instances of PEP overuse [11, 15-17] and suggested that such costly policy failures can be exacerbated by “media hysteria.” [17])

The point here is not to suggest that dogs are the real rabies threat, only to provide some critical context—thereby challenging the claim made by Roebling and her colleagues that “rabies transmission via feral cats is a particular concern as demonstrated by the significant proportion of rabies post-exposure prophylaxis associated with exposures involving cats.” [1]

Simply put, these folks found exactly what they were looking for because they knew where to look. And, just as important, where not to.

• • •

It’s difficult to see “Rabies Prevention and Management of Cats” as anything other than an endorsement of ABC’s long-standing witch-hunt against free-roaming cats by the CDC (and to a lesser degree, USDA). The authors of the paper, however, would have us believe otherwise, writing in the acknowledgments: “The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention.” [1]


So why bother using their agency affiliations if this wasn’t “official business”? So it would be published, of course. And would get greater traction in the media. At which point Roebling and her colleagues would, what—suggest this was just some sort of side project? A hobby, perhaps? (The assumption apparently being: taxpayers would either not object, or never notice in the first place.)

ABC’s leadership decided long ago that science has little to do with the pursuit of knowledge; it’s a tool for advancing their agenda. We have every right to expect better, though, from the people at CDC—whether on or off the clock.

So how does something like this happen? As I see it, there are really only three possible scenarios:

  1. The authors simply don’t know any better;
  2. The authors know better, but sought publication anyhow; or
  3. Those authors who know better signed off on the manuscript blindly.

None of which brings to mind pretty thoughts.

* Five from CDC, and one from USDA.
** USDA’s Wildlife Services—whose questionable, secretive practices have recently been the subject of increased scrutiny—being a notable exception.
*** Although the article didn’t appear in print until the May 2013 issue, it was published online July 26th of 2012.

Literature Cited

1. Roebling, A.D., et al., Rabies Prevention and Management of Cats in the Context of Trap–Neuter–Vaccinate–Release Programmes. Zoonoses and Public Health, 2013: p. n/a-n/a.

2. Gerhold, R.W. and D.A. Jessup, Zoonotic Diseases Associated with Free-Roaming Cats. Zoonoses and Public Health, 2013. 60(3): p. 189–195.

3. Natoli, E., et al., Management of feral domestic cats in the urban environment of Rome (Italy). Preventive Veterinary Medicine, 2006. 77(3-4): p. 180–185.

4. Lamb, W., Commentary on economic valuations of biodiversity. Ecological Economics 2013. 89: p. 170–173.

5. Little, S., A review of feline leukemia virus and feline immunodeficiency virus seroprevalence in cats in Canada. Veterinary Immunology and Immunopathology, 2011. 143(3-4): p. 243–245.

6. Lee, I.T., et al., Prevalence of feline leukemia virus infection and serum antibodies against feline immunodeficiency virus in unowned free-roaming cats. Journal of the American Veterinary Medical Association, 2002. 220(5): p. 620–622.

7. Blanton, J.D., et al., Rabies surveillance in the United States during 2010. Journal of the American Veterinary Medical Association, 2011. 239(6): p. 773–783.

8. CDC, Human rabies prevention–United States, 2008: Recommendations of the Advisory Committee on Immunization Practices. MMWR Recommendations and Reports, 2008. 57(RR03): p. 1–28.

9. CDC, Epidemiologic Notes and Reports Cat Rabies Exposures in Iowa—1981. MMWR Weekly, 1982. 31(6): p. 67–68, 73.

10. CDC Cost of Rabies Prevention. 2011.

11. Recuenco, S., B. Cherry, and M. Eidson, Potential cost savings with terrestrial rabies control. BMC Public Health, 2007. 7(1)

12. Christian, K.A., et al., Epidemiology of rabies post-exposure prophylaxis—United States of America, 2006–2008. Vaccine, 2009. 27(51): p. 7156-7161.

13. Gerhold, R.W. and D.A. Jessup, Zoonotic Diseases Associated with Free-Roaming Cats. Zoonoses Public Health, 2012

14. Moran, G.J., et al., Appropriateness of rabies postexposure prophylaxis treatment for animal exposures. Emergency ID Net Study Group. Journal of the American Medical Association, 2000. 284(8): p. 1001–1007.

15. Wyatt, J.D., et al., Human rabies postexposure prophylaxis during a raccoon rabies epizootic in New York, 1993 and 1994. Emerging Infectious Diseases, 1999. 5(3): p. 415–423.

16. Krebs, J.W., S.C. Long-Marin, and J.E. Childs, Causes, costs, and estimates of rabies postexposure prophylaxis treatments in the United States. Journal of Public Health Management and Practice, 1998. 4(5): p. 56–62.

17. Noah, D.L., et al., Mass human exposure to rabies in New Hampshire: exposures, treatment, and cost. American Journal of Public Health, 1996. 86(8): p. 1149–51.

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