Public Health Issues

Below are papers that make clear the Rabies Guide is the correct stance in respect to TNR.  We simply cannot ignore major health issues which accompany stray and feral cats.  We present a substantial number of peer reviewed journal articles below, organized by the disease.  One of the more troubling papers to consider is located under the Roundworms and Hookworms section, and focuses on the impact of these diseases in low income areas.  The disparity in disease prevalence is signficant.  Note these diseases are not grouped in any particular order of importance, as all diseases relevant to public health are important.



Rabies Statistics and General Information from the Centers for Disease Control (2012)

The Centers for Disease Control refers to Rabies in the United States as “a serious threat to the health of people and animals.”  The continue by noting that more than 40,000 people annually are required to get rabies shots after being bitten by a rabid animal.  Interestingly, feral cat advocates will cite the information from the CDC which notes that “More than 90% of all rabid animals reported to CDC each year occur in wildlife” while completely ignoring the following two sentences, which states, “the main animals that get rabies include raccoons, skunks, foxes and bats. However, most people are exposed to rabies due to close contact with domestic animals, such as cats or dogs.”  Most importantly, the very next statement made is in bold print and says “Rabies in Cats on the Rise.”  The CDC continues by stating, “While dogs have historically been associated with rabies transmission to humans, cats are more likely to be reported rabid in the U.S. Cats are often in close contact with both humans and wild animals, including those that primarily transmit rabies. This creates a situation in which rabies may be more easily transmitted from to humans from cats.  In 2009, rabies cases among cats increased for the second consecutive year. Three times more rabid cats were reported than rabid dogs.”

The CDC recommends the following noteworthy ideas in respect to the question of TNR:

“•Maintain control of your pets by keeping cats and ferrets indoors and keeping dogs under direct supervision when outdoors.

•Call animal control to remove all stray animals from your neighborhood since these animals may be unvaccinated.

Do not feed or water your pets outside and keep your garbage securely covered. These items may attract wild or stray animals.” [Emphasis added]

All of this information can be viewed at the CDC web page on Rabies here.

Detailed information on Rabies Surveillance can be seen at the CDC Rabies page here.  This includes the rabies surveillance reports from 2002-current.

Below are CDC Rabies Surveillance Reports from prior years.  They are archived on the CDC site and harder to find, but attached are PDF files for review with the respective years noted:

Rabies Survey 1995 National Institute of Health

Rabies Survey 1988 CDC

Rabies Survey 1987 CDC

Florida Department of Health Surveillance of Diseases (2010)

The most recent statistics for Rabies and Rabies Exposures are for 2010, when we discover that more than 2000 people were exposed to rabid or potentially rabid animals in Florida in 2010.  This represents a 46% increase over the five year average, and cats represented 25% of the incidents.  Several of the specific reports are available below, as well as the link to the Florida Department of Health where all the reports for many years can be accessed.

Read the 2010 Survey Report:  State of Florida DOH Reported Diseases 2001 2010

Read the 2010 Report Summary for Rabies:  Rabies_Animal 2010 Data report summary

Read the 2010 Report Summary for Rabies Exposures:  Rabies_Exposure 2010 Data Report Summary

Access the Florida DOH website for disease reporting here.

Temporal dynamics of rabies in a wildlife host and the risk of cross-species transmission.  Journal of Epidemiology and Infection (2004).

This paper discusses the cross species transmission of rabies from raccoons to cats.  The paper establishes that “Cats are the domestic animal most frequently diagnosed with rabies in the United States [11]. Cases among cats are most common in the eastern United States.” The paper also states “cats are involved in many of the 45 000 annual human ‘exposures’ to rabies virus that result in administration of post-exposure rabies prophylaxis (PEP) [41]. In rural Pennsylvania, cat encounters accounted for 44% of human PEPs, more than any other species [26]. In urban emergency rooms, cats accounted for >15% of patients receiving PEP [42]. The average rabid cat generates between 1 and 6 human PEPs [19, 24]. Rabid cats have been the cause of several mass exposures involving >25 PEPs [43] and, in one instance, >650 PEPs [27]. In the latter case, the cost of rabies vaccine and immunoglobulin alone exceeded $1 000 000. PEP represents only a fraction of the total public-health costs associated with rabid cats. Specimen submissions and diagnostic testing, contact tracing of exposed persons, and professional evaluation of the exposure prior to PEP are all resource-intensive activities [12, 44].”

Read the paper:  Rabies in Raccoons and Cross Species Transmission with Cats CDC Nov 2003

Florida Department of Health 2012 Rabies Guide (2012)

The Florida Department of Health 2012 Rabies Guide is a document to which veterinarians are very familiar.  This document gives us our protocols for the prevention of, and the reporting of, rabies.  Most importantly to our consideration with feral cats is the very beginning of the document, which includes the executive summary.  The quote at the beginning of the TNR pages comes from this summary, and makes clear that feral cats are untenable on public health grounds!

Read the paper:  RabiesGuide2012

Compendium of Animal Rabies Prevention and Control, 2011

This is the document that informs Veterinarians in respect to Rabies vaccines, and the requirements for those vaccines.  This document informs that the protocol for even the best run TNR programs fails this vaccine standard of care miserably.  Page 12 shows the standards for each type of Rabies vaccine sold, and all of them require boosting!  We are not aware of any TNR program that boosts the vaccine provided at the time of sterilization.  Also, this National Public Health group of veterinarians recommends for rabies control, “Stray dogs, cats, and ferrets should be removed from the community. Local health departments and animal control officials can enforce the removal of strays more effectively if owned animals are required to have identification and are confined or kept on leash.”

Read the report:  Rabies Compendium National Public Health Vets 2011

Cat Attacks of Recent Note, various news sources (2012).

There appears to be some confusion about whether a feral or stray cat will “attack” someone, with TNR advocates claiming the cats are afraid of humans and too shy to approach.  This is simply not true, as anyone who understands the furious variant of Rabies knows.  The fact is Rabies will cause animals (including humans) to attack and attempt to bite, which is actually the Rabies virus driving the host to spread the virus to the next host.  In all of these stories, you will see the common theme is the attack aspect of the victim’s report.  Bottom line, rabid cats exist; and they DO attack!

Watch a video news report here (and hear the young female victim talking about how the cat attacked her).

Watch another video news report here (again, a victim describing the attack).

Read the report here:  North Ga Cat Attacks 4 People Aug 2012

Read the report here:  Another Rabid Cat Attack – August 15 2012 New York

Read the report here:  NY July 2012 Rabid Cat attacks man

Read the report here:  Another Feral Rabid Cat June 2012

Read the report here:  Two more Rabies cases from Feral Cats May 2012



Toxoplasma oocysts as a public health problem.  Trends in Parasitology, 10 July 2013 E. Fuller Torrey, Robert H. Yolken

As researchers continue to examine the parasite T. Gondii, it becomes clear why feral cat TNVR is a very bad idea for communities around the country. Alarmed by rising outbreaks of toxoplasmosis in water supplies, the authors of the latest study plainly discuss transmission methods and the critical need to control feral cat populations and their feces. TNR advocates demonstrate a profound disregard for the clear science behind these reports because fecal control isn’t possible in free roaming cats. The authors are researchers at highly regarded medical institutions, including John Hopkins University Medical Center.

In the introduction, the authors note:

“When T. gondii infects previously seronegative pregnant women it may cause a congenital syndrome that includes deafness, seizures, retinal damage, and mental retardation in the fetus or neonate. In immunocompromised individuals, such as those with HIV infection or undergoing immunosuppressive chemotherapy, it may produce severe central nervous system damage, seen less often since the introduction of effective antiretroviral treatment. Until recently, T. gondii infection was assumed to be largely asymptomatic in immunocompe- tent individuals. This notion is now under reconsideration following the outbreak of toxoplasmosis epidemics, including ocular toxoplasmosis, which are associated with T. gondii oocyst contamination of water [6–12]. Additional concerns have been raised by recent studies of schizophrenia [13], depression [14], suicidal behavior [15], obsessive–compulsive disorder [16], rheumatoid arthritis [17], brain cancer [18], and scholastic underachievement in children [19], which have reported correlations between such conditions and elevated T. gondii seropositivity rates as compared with those in control populations.” (Emphasis Added)

Read the paper HERE.

Unrecognized Ingestion of Toxoplasma gondii Oocysts Leads to Congenital Toxoplasmosis and Causes Epidemics in North America.  Journal of Clinical Infectious Diseases(December 2011).

This paper, for those who understand the basics of T. Gondii, will be a real eye-opener.  Here we discover that recent improvements in testing now allow differention between tissue cysts from intermediate hosts, and oocysts which only come directly from cats.  Contrary to previous beliefs, which held that meat exposure was the primary source of toxo in humans, testing showed very low frequencies of T. Gondii in meat.  Additional developments show congenital toxoplasmosis being passed on by mothers with NO exposure to cat risk factors (like changing litter boxes, etc).  The panel notes “In the United States, there are an estimated 73 million feral cats and 78 million domestic cats [31], which allows for environmental contamination by oocysts to be the source of infection even for those who do not own cats. Hill et al recently determined that there was a low prevalence of tissue cysts currently in retail meats in the United States, including beef, chicken, and pork [32]. The low frequency of infected meat suggests that cats potentially were a cause for much T. gondii infection in the United States.”

Read the paper here: Toxoplasmosis and Unrecognized ingestion of Oocysts with Congenital defects 2011 – Copy

Waterborne Toxoplasmosis – Recent Developments.  Journal of Experimental Parasitology (2009).

This paper by the CDC and others demonstrates the presence of T. Gondii in the water supply, and notes, “Until recently, waterborne transmission of T. gondii was considered uncommon, but a large human outbreak linked to contamination of a municipal water reservoir in Canada by wild felids (cats) and the widespread infection of marine mammals in the USA provided reasons to question this view.”

Read the paper here:  Waterborne Toxoplasmosis Recent Developments 2009

Predator Cat Odors Activate Sexual Arousal Pathways in Brains of Toxoplasma gondii Infected Rats.  PLOS One (Aug. 2011).

This paper, based on previous research that shows toxoplasmosis is particularly effective in invading the brain, demonstrates exactly what the title implies – that toxo drives the rats right back to the cat to complete the life cycle of T. Gondii.  The authors note, “approximately one-third of humans are seropositive for Toxoplasma across the world [16], and several recent studies find infection increases risk for schizophrenia [17,18,19] and obsessive compulsive disorder [20], diseases noted for elevated dopamine levels and disturbed amygdala function [21]. Our results are therefore of wide interest, as the ability of Toxoplasma to dramatically alter host behavior and proper amygdala functioning may extend beyond the rat into ancillary Toxoplasma hosts, including humans.”

Read the paper here:  Cat Odors Activate Sexual Arousal pathways in Toxo Rat Brains August 2011

Toxoplasmosis – an Update.  Journal of Tropical Parasitology (June 2011)

This paper provides a current update on Toxoplasmosis, including reminding us that 16-40% of US residents have Toxoplasma Gondii (T.Gondi), the parasite that causes Toxoplasmosis.  This paper also covers concerns related to HIV positive people, and establishes that 10% of all deaths of people with HIV are directly from Toxoplasmosis.  T.Gondii is one of the biggest public health issues we have as veterinarians.  Due to both incidence rates and clinical effects , T. Gondii alone is sufficient reason to stop conducting TNR, as it unwittingly contributes to the spread of T. Gondii.  Worse, the more we learn about T. Gondii’s abilities, the more we grow concerned.

Read the paper:  Toxo Update June 2011

T.Gondii (Toxoplasmosis) – Basic Biology.  Centers for Disease Control (2012)

This paper provides an overview of the biology of T.Gondii, demonstrates that the feline is the DEFINITIVE HOST of T. Gondii, and shows how T. Gondii moves from the host into us via direct and indirect contact.

Read the paper: CDC – Biology of Toxoplasmosis – Cat is definitive host

Editors’ Introduction: Schizophrenia and Toxoplasmosis.  Schizophrenia Bulletin – John Hopkins (2007).

This article is an excellent overview of the issues related to T. Gondii and mental illness.  The introduction notes, “The facts that T. gondii is neurotrophic, affects neurotransmitters, is apparently suppressed by some antipsychotic drugs, and has predisposing genes make an etiological link between toxoplasmosis and schizophrenia inherently plausible.”  Even more recent research is shocking, and the next paper below has more current research on this issue.

Read the paper here:  Introduction to Schizophrenia and Toxo John Hopkins April 2007

Toxoplasma on the Brain: Understanding Host-Pathogen Interactions in Chronic CNS Infection.  Journal of Parasitology Research (2012).

This paper is chilling for those with the medical knowledge to really understand the details.  Even for those without formal training, however, observations including that, “Until recently, T. gondii chronic infections were considered largely innocuous in the otherwise healthy patient, despite observed neurological changes. However, more recent studies on model animals have suggested that behavioral changes are manifest following infection [14]. Moreover, recent associations have been made between parasite infection and neurological disorders, such as schizophrenia.”

Read the paper here: Toxoplasma on the Brain Journal of Parisitiology Jan 2012

Toxoplasma Gondii Immunoglobulin G Antibodies and NonFatal Suicidal Self Directed Violence.  Journal of Clinical Psychiatry (Aug 2012).

Here, we see a recent study done that confirms previous reports of higher suicide rates of those infected with T.Gondii.  As the abstract notes, “results are consistent with previuos reports on the association between T. Gondii and [suicide attempts].”  You can read the Science report below, as well as see the abstract.

Read the abstract here:  Abstract Journal of Psychiatry T Gondii and Suicide Attempts

Read the story in Science Daily here.

Case Study.  New England Journal of Medicine (2012).

This case study is of a patient with toxoplasmosis, which led to brain lesions and ultimately death.  The T. Gondii was opportunistic and infected the patient, who was also HIV positive.

Read the case study here:  New England Journal of Medicine Case Study Toxoplasmosis in HIV positive man

Toxoplasma in Humans and Animals in the United States, Journal of Parasitology (2008).

This is another good overview paper about T. Gondii.  One key point the author makes early in the work has particular importance for those of us who live in tropical environments.  The author observes, “The western region of the USA is generally drier and oocysts may not survive as well in the soil in this climate. However, due to variations in weather, cat populations and human behavior, there is likely to be a wide variation in T. gondii prevalence within regions of the USA.”  In Florida, with our environment, oocysts will survive very nicely, and studies have shown the survival rate is measured in years, not days!

Read the paper here:   T Gondii infection in Humans and Animals in the US J of Parasitology 2008



Pet roundworms and hookworms: A continuing need for global worming. Parasites & Vectors 2012.

This paper is an excellent overview of Roundworms and Hookworms, which the author refers to as “the old fashioned” concern, simply because we have such a good understanding of how these parasites work.  A key observation from the paper:  “In fact, updated information on prevalence of parasites of dogs and cats and the risk factors associated with infection, as well as reinforcing veterinary and public health concerns, is of crucial relevance…The cornerstone to control intestinal parasitoses of pets is a combination of strategic worming methods (especially puppies, kittens and dams), wearing footwear when needed, supervising playing children and their interactions with pets, breaking faecal-oral routes by washing hands and removal and disposal of faeces from public and private grounds…”  This paper reminds us why we have dog feces stations in parks, and why we require owners to pick up their animal feces.  Some of the fundamentals expressed in this paper are also why we contain all animal feces, including human.  The grossness of this subject underlies the whole point of concern – county funded or endorsed TNR will release (literally based on shelter statistics) tens of thousands of cats onto the streets of our county each year.  Each outdoor cat creates a substantial fecel load which contaminates our environment – and implicates our public health on an easily understood level:  poop is bad!

Read the paper here:   Pet Roundworms and Hookworms 2012

Hookworms in Feral Cats in Florida, Journal of Parasitology, (2003)

There was recent confusion suggesting that hookworms were no longer found in Florida, which could hardly be less true.  This abstract shows a infection rate of feral cats for hookworms of 75%!

Read the abstract here:  Hookworms of feral cats in Florida

Ocular Toxocariasis in the US 2009-2010, CDC, Morbidity and Mortality Weekly (June 2011).

This summary from the CDC makes it clear that while ocular toxocariasis is not terribly common (600-700 cases/yr), it is terribly debilitating to those infected with these parasites (which come from both dogs and cats).  For those effected, blindness is the most common end result, with children bearing the high portion of the cases.  As the summary notes, the average age of the patient was 8.5 years and more than half of the new cases were from the south.  Again, this has much to do with our environment, which is very favorable to parasites and their eggs.  Roundworms and their eggs can remain in the soil for years, which is why proper and timely fecal disposal is so important.

Read the paper here: Ocular Toxocarisis CDC Survey 2009-2010

Hookworm General Information, CDC (2010-2012).

Below is the overview of Hookworms from the CDC, as well as a Frequently Asked Questions sheet.  Dogs and cats are both carriers for hookworm, and hookworm and roundworms are a primary reason pet owners are urged to quickly pick up any fecal matter and properly dispose of it.  You can also jump to the CDC site on hookworms here.

Read the overview here:  Hookworm CDC Epidemiology 2010

Read the FAQ here:  Hookworm Frequently Asked Questions CDC 2010

Neglected Infections of Poverty In the United States, National Library of Medicine, 2011.

This paper shows how disparate the impact of toxocariasis and toxoplasma is within low income and under-privileged areas of our country.  The author notes, “major neglected infections include…toxocariasis…toxoplasmosis [and these] disease occur predominantly in people of color living in the American South, in disadvantaged urban areas…[and] represent some of the greatest health disparities in the United States.”  Because we do not require reporting of many of these diseases, the true impact may never be fully understood, but this paper certainly highlights the issues.

Read the paper here:  Neglected Infections of Poverty in the US National Academies Press 2011




Cat Scratch Disease.  CDC (2012)

This is another common problem that comes only from cats, thus the name.  As shown on the CDC webpage, “cats can spread B. henselae to people. Most people get CSD from cat bites and scratches. Kittens are more likely to be infected and to pass the bacterium to people.”

You can read more:  CDC web page here.

Unraveling Mysteries Associated with Cat Scratch Disease.  Journal of Emerging Infectious Disease (1995).

This paper discusses the difficulties in identifying the underlying culprit of CSD, and notes, “For many years, CSD has been clinically diagnosed when three of the following four criteria are met in a patient: 1) history of traumatic cat contact; 2) positive skin-test response to CSD skin-test antigen; 3) characteristic lymph node lesions; and 4) negative laboratory investigation for unexplained lymphadenopathy.”

Read the paper here:  Bartonella Journal of Infectious Disease

Cat Scratch Disease in Children, CDC Morbidity and Mortality Weekly, (2002).

This paper highlights 5 cases of CSD in children in Texas from 2001.  The paper notes the estimated burden of this disease in the US is “22,000 cases. Although CSD occurs in persons of all ages, the highest age-specific incidence is among children aged <10 years (2). Infection with B. henselae is one of the most common causes of chronic lymphadenopathy among children, and in some case series up to 25% of the these infections result in severe systemic illness (3).”

Read the paper here:  Cat Scratch Disease in Children CDC 2002



Cat Associated Zoonoses.  Journal Of Internal Medicine (2002).

This is the paper that is cited in the Alley Cat Alley literature to support feral cats as healthy residents of the community.  However, any fair reading of this paper makes it clear the author is talking about owned, well cared for pet cats, not feral cats.  Further, a read of this paper makes clear that many of the cat associated zoonoses (which Alley Cat Allies alleged fact sheet states are not connected to cats even while citing this paper for other reasons – despite this paper stating these diseases come from cats!) are severe and can even include “life threatening conditions, such as bubonic plague…cat-related diseases are also not uncommon.”

Read the paper here:  Internal Medicine 2002 Cat Associated Zoonoses

Outdoor fecal deposition by free-roaming cats and attitudes of cat owners and nonowners toward stray pets, wildlife, and water pollution.  JAVMS (2006).

This is an interesting paper that speaks to the enormous volume of fecal load spread by outdoor cats. As the paper observes, “Although much attention has been focused on the effect of free-roaming cats on wildlife, little consideration has been given to the contribution of owned and feral cats to fecal pollution. Results of several studies13,14 suggest that pet feces contribute to bacterial loading of streams and coastal waters. A study15 of Escherichia coli ribotypes in Morro Bay, Calif, and its inflows reveals that 2.5% of all isolates are of felid origin, with a higher proportion (7.4%) from felids at the Pismo Seep downstream from Los Osos. In the southern sea otter (Enhydra lutris nereis) range from Half Moon Bay to Point Conception near Santa Barbara, Calif, Toxoplasma gondii, a protozoan parasite shed only in the feces of felids,16 caused 16% of southern sea otter deaths that were evaluated from 1998 to 2001.17 Fifty-two percent of dead and 38% of live southern sea otters sampled from 1998 to 2004 were infected with T gondii.”

Read the paper here:  Environmental Contamination by Feral Cat Feces JAVMA

Plague:  A Veterinary Perspective.  JAVMA (2003)

As the paper notes, when one thinks plague the image is of the “black death” of the medieval times, when 1/3rd of the Europe’s population died from plague.  However, the reality is 10-15 people a year die of plague in the US.  Of those, the author notes, “Although most humans with plague were exposed through a bite from an infected flea, others have become infected as a result of contact with infected wild animals such as rabbits and wild rodents and infected domestic cats.”  Not only can cats be infected, but more commonly they serve as the carriers of the fleas which are the vectors for most plague cases.

Read the paper here:  Plague – The Veterinary Perspective JAVMA 2003