Hellard E, Fouchet D, Santin-Janin H et al: When cats’ ways of life interact with their viruses: a study in 15 natural populations of owned and unowned cats (Felis silvestris catus), Preventive Veterinary Medicine 101:250, 2011.
Cats are susceptible to a number of important viruses that can cause significant disease. The living conditions and behavior of various cat populations will affect their susceptibility and risk of exposure to these viruses. The investigators examined 15 populations of non-sterilized unvaccinated cats living in the same area of France. These populations had one of two different lifestyles – owned (sheltered and fed, socialized) and unowned (no shelter or food provided, unsocialized). Blood samples were tested for exposure of the cats to feline herpesvirus (FHV), calicivirus (FCV), parvovirus (FPV), immunodeficiency virus (FIV), and leukemia virus (FeLV). Not surprisingly, the unowned cats were more likely to have been infected with FHV, FCV, and FIV – these viruses largely require direct contact between cats, including fighting. The owned cats were more likely to have been infected with FPV. For each virus, the likelihood of having been infected varied with the population. For example, FIV infection was more likely in older, male, unowned cats; FHV was more likely to infect kittens at an earlier age in unowned versus owned populations; FPV infection was more likely in owned populations perhaps because of shared environments in human settlements. The main crux of this paper was that the epidemiology of a particular virus within cat populations can be affected by their behavior and lifestyle. Failure to consider these aspects can skew results of epidemiologic analyses. For example, when the status of the owned and unowned cats were combined, a different epidemiologic picture was seen for the various viruses examined – the risk factors were different, and included such factors as body mass. Pooling different types of cats in a single sample without taking behavior and lifestyle into account could give a misleading picture of the epidemiology of their viruses. [MK]