Cats in TNR programs have a lower incidence of feline herpesvirus (FHV), one of the pathogens responsible for feline upper respiratory infections (URI), than cats in shelters.

While cats in animal shelters, foster homes and TNR programs all carry pathogens that can cause URI, the stress of being in a shelter, along with other factors such as potential exposure to dogs who have been vaccinated for, or who are shedding, bordetella bronchiseptica, may be responsible for the high rates of feline URI seen in shelter populations.

In a study supported by a Maddie's Fund^® grant and published in the August 2014 issue of The Veterinary Journal, researchers found:

The stress that cats experience when placed in the unfamiliar environment of a shelter, particularly when housed in undersized cages which do not provide opportunities to hide, and near to dogs, could account for the high rate of FHV in traditional STS [short term shelters] observed in this and other studies. In contrast, community cats in TNR programs had the lowest prevalence of FHV. This might indicate that their free-roaming status gives TNR cats more options to avoid close contact with other cats and to avoid stressful circumstances such as shelter confinements that can trigger reactivation of latent FHV infections.

The entire study, which includes data on other URI pathogens in different management models, can be scanned for free, or rented for thirty days for $4, from Deep Dyve.

C.M. McManus, J.K. Levy, L.A. Andersen, S.P. McGorray, C.M. Leutenegger, L.K. Gray, J. Hilligas, S.J. Tucker, Prevalence of upper respiratory pathogens in four management models for unowned cats in the Southeast United States, The Veterinary Journal, Volume 201, Issue 2, August 2014, Pages 196-201, ISSN 1090-0233, http://dx.doi.org/10.1016/j.tvjl.2014.05.015.