Feline Panleukopenia is caused by feline parvovirus (FPV). Parvoviruses are small, non-enveloped DNA viruses that replicate only in rapidly dividing cells. The virus is hearty and capable of viability for many months to years in the environment. Shedding of the virus is primarily through contaminated feces of infected cats and transmission is fecal-oral. Fomites also play an important role in the transmission of FPV because of prolonged survival of the virus on contaminated surfaces (cages, food bowls, litter boxes and health care workers). The disease is most common in young kittens, although occasional cases are reported in adults. Infection of the feline fetus or the neonate, either as a result of naturally acquired infection or MLV vaccination, may lead to cerebellar hypoplasia. The infection results in fatal disease in a large percentage of susceptible cats. Immunity to parvovirus infection is through antibody response to natural infection, vaccination or through passive transfer of maternal antibodies from queen to kittens. Maternal antibody may interfere with immunization when antibody titers are high. Maternal antibody titers are high during the neonatal period but generally wane to levels which allow immunization by 12 weeks of age. An occasional kitten may retain interfering levels of maternal antibodies beyond 12 weeks in exceptional cases. The immunity conferred by FPV vaccines is considered to be excellent. Most vaccinates are completely protected from clinical disease. The panel considers this to be a CORE vaccine. Therefore, all cats should receive a foundation series of vaccinations for kittens according to recognized protocols followed by a booster one year later. Annual booster vaccination is recommended by the biologics manufacturer. DOI studies beyond one year have not been performed by any U.S. biologics manufacturers to date. A recent study demonstrated protective titers for at least 6 years (See AppendixF). The panel recommends booster vaccinations be given every three years following the initial one year booster.

The majority of feline upper respiratory disease (80 - 90%) is caused by feline herpesvirus I (FHV-1), the cause of viral rhinotracheitis and feline calicivirus (FCV). FHV-1 and FCV are both shed in ocular, nasal, and pharyngeal secretions of infected cats. In addition, FCV may be shed in the feces. Transmission occurs through sneezed macrodroplets, direct from cat to cat, or via contaminated fomites (hands, feeding bowls, etc.) The disease is self-limiting; however, infected cats may develop chronic oculonasal disease and most of infected cats become intermittent (FHV-1) or persistent shedders of virus (FCV). The latent state for FHV-1 is retained for the life of the cat while FCV infected cats usually overcome the carrier state. Although the disease is rarely fatal in adult cats, young kittens may develop severe disease and death occurs in some cases. A limping syndrome and chronic gingivitis stomatitis syndrome have been attributed to FCV infection in cats both as a result of natural infection and subsequent to vaccination. Risk of exposure is high because both organisms are ubiquitous.

Immunity to FHV-1 and FCV infection is through both antibody and cell-mediated immune response to natural infection, vaccination or through passive transfer of maternal antibodies from queen to kittens. Maternal antibody may interfere with parenteral immunization. Intranasal vaccines appear capable of immunizing against FHV-1 and FCV in the presence of maternal antibodies. Maternal antibody titers wane to levels which allow immunization by 12 weeks of age. Actively acquired virus neutralizing titers in excess of 1:2 are considered protective against clinical disease for FHV-1 and titers in excess of 1:4 are considered protective against clinical disease for FCV. In contrast to FPV vaccines which provide very high levels of protection against disease, vaccine for FHV-1 and FCV tend to provide protection from serious disease. Vaccinated cats tend to become infected after challenge, but have reduced clinical signs, and reduced level of virus shedding. The panel considers these to be CORE vaccines. Therefore, all cats should receive a foundation series of vaccinations for kittens according to recognized protocols followed by a booster one year later. Annual booster vaccination is recommended by the biologics manufacturer. DOI studies beyond one year have not been performed by any U.S. biologics manufacturers to date. The panel recommends booster vaccinations be given every three years following the initial one year booster. This recommendation is based on serologic data (see Appendix F) that indicates prolonged protective titers to FHV-1 and FCV in isolated cats. Veterinarians may elect to vaccinate more frequently based on the risk assessment of their patients. Cats housed periodically in boarding facilities are assumed to have increased risk. The risk of the individual cat should be assessed when considering annual vs. triennial vaccination against these viruses. The use of vaccines approved for topical administration on mucosal (conjunctival & intranasal) surfaces should be considered. The advantages of these vaccines are rapid protection and protection at the site of infection. They also provide systemic immunity, lack of interference by maternal antibody, and an alternate route of administration.. In highly endemic situations, exceptions to standard vaccine protocols may be necessary to provide as early protection as possible. In these situations, the use of an intranasal vaccine for FCV and FHV-1 as early as 2 weeks of age administering 1-2 drops per kitten appears to be reasonably safe and effective. Disadvantages of mucosal (intranasal and conjunctival) vaccination include possible sneezing, coughing, and conjunctivitis post vaccination, and potential shedding of vaccine virus.

Chlamydia psittaci is a bacterial respiratory pathogen. Transmission is through direct cat-to-cat contact. The organism is unstable in the environment and fomite transmission is less likely to occur. Clinical signs usually appear 5 to 10 days after infection. Serous conjunctivitis, which is initially unilateral and ultimately bilateral, is the most common clinical sign. Sneezing or nasal discharge, if they occur, are usually mild. Chlamydia psittaci is considered a relatively minor respiratory pathogen of cats in the U.S., responsible for approximately five percent or less of feline respiratory disease. Its prevalence is greater in the United Kingdom where it is considered a more important component of respiratory disease. The immunity conferred by chlamydia vaccines is similar to FHV-1 and FCV. Vaccinated cats have reduced clinical disease and are protected from severe clinical disease after challenge. It is the experience of this panel that chlamydia vaccines have adverse systemic response rates that are greater than other common vaccines. Since there is low disease incidence, this vaccine is considered to be NON-CORE. Its use should be restricted to cats at risk of exposure. Vaccination according to label recommendations is recommended. Annual booster vaccination is recommended by the biologics manufacturer. DOI data of greater than one year duration is not available. In the absence of data to demonstrate a DOI longer than one year, annual boosters are recommended for cats receiving chlamydia vaccination.

Rabies is caused by an RNA virus transmitted through direct contact with infected mammals (primarily bite wounds). More cats than dogs are diagnosed with rabies infection in the U.S. Cats and dogs, although relatively resistant to rabies, serve as a potential source of infections for humans. The potential susceptibility of the cat to develop rabies varies according to the strain of virus, quantity of virus injected, site of inoculation, age of the cat, immunocompetence, and prior immunization. Treatment is ineffective in cats that demonstrate clinical signs. Due to the high zoonotic potential, rabid cats should not be treated. In all cases of suspected or known rabies infection, local health department officials should be notified. Proper precautions and quarantine procedures as outlined by local regulations and described in the Compendium of Animal Rabies Control should be followed. Rabies vaccines are considered to have excellent levels of efficacy. Rabies is considered to be a CORE vaccine. Rabies vaccination in cats is often regulated by local or state government and recommendations regarding proper vaccination of domestic cats against rabies is in the domain of these regulatory agencies. Manufacturers of rabies vaccines have performed studies establishing minimum DOI for their products as required by USDA. Results of these studies indicate that 3 year rabies vaccines demonstrate effective immunity and suggest no advantage to the use of one year minimum DOI rabies vaccines. Recommendations for vaccination of cats against rabies should take into consideration the use of products with longer DOIs. The panel recommends that 3 year DOI rabies vaccines be used wherever regulations allow. This will result in the need for fewer injections of vaccines in cats. Finally, the panel recommends that the clinician comply with local or municipal law and recommendations set forth in the Compendium of Animal Rabies Control. At the same time, practitioners and veterinary organizations are urged to influence authorities to make future rabies vaccination consistent with the available science - namely that triennial vaccination using a 3-year vaccine is efficacious.

FeLV is one of three exogenous retroviruses currently recognized in cats. FeLV infects domestic cats throughout the world. The infection rate seems to be directly related to population density. Urban areas, where cats are allowed to roam free, have a higher incidence of disease than rural areas. FeLV is carried by healthy, subclinically infected or chronically ill cats. Transmission is through prolonged intimate contact with infected cats, bite wounds, in-utero or via milk transmission from queen to kitten. Experimental data demonstrates that young kittens (<16 weeks) are highly susceptible to infection. Kittens older than 16 weeks and adult cats seem to be much less susceptible to infection and disease. Clinical signs of FeLV consist of disease resulting from either immunosuppressive disorders or neoplasia. Testing and identifying positive cats is the mainstay of managing FeLV infection and is not supplanted by vaccination. The ELISA test is recognized as the preferred screening test for FeLV. FeLV vaccination is recommended only for cats that have lifestyles which place them at-risk for exposure to the organism. These include outdoor cats, indoor/outdoor cats, stray cats, feral cats, open multi-cat households, FeLV-positive households, and households with unknown FeLV status. Indoor cats are unlikely to become infected unless they fall into one of the at-risk groups. Vaccination of cats based on risk vs. benefit probably favors the use of the vaccine in cats that are at high risk for exposure. The panel recognizes the inherent problems in assessing risk vs. benefit in the cat population due to difficulties in assessing the owners lifestyle information about their cats. The immunity conferred by FeLV vaccines is considered fair to good, with variability in efficacy of the different FeLV vaccines. Efficacy is determined by ability to prevent persistent viremia post vaccination. Normally, vaccinated cats that are challenged do not experience clinical signs and are protected from persistent viremia post vaccination. The panel considers this to be a NON-CORE vaccine. The panel recommends that cats at risk (defined above) be given a foundation series of vaccinations for kittens according to recognized protocols demonstrating efficacy as recommended by the manufacturer. Annual booster vaccination is recommended by biologics manufacturers. DOI studies beyond one year have not been performed by any U.S. manufacturer. Without evidence to support longer DOI, annual revaccination of these at-risk patients would be appropriate. Due to the increased susceptibility of young cats and the inability to precisely define a cat's environment at this early age, some panel participants favor initial vaccination of all kittens with subsequent booster vaccinations given only to those cats that belong to an at-risk group.

FIP is caused by a coronavirus and is a disease of domestic and exotic cats. Transmission is thought to occur through oronasal contact with contaminated feces. Queens may transmit the virus to kittens in the preweaning period. The precise reservoir is unknown but is suggested to be carrier cats or subclinically ill cats. There is controversy as to what constitutes an FIP virus (FIPV), but current theory suggests that both FIPV and feline enteric coronavirus (FECV) have the propensity to induce FIP in a susceptible cat. FECV virus is regarded as the parent virus of FIPV, mutating in certain cats. Two distinct forms of the disease exist, an effusive (wet) form and pyogranulomatous (dry) form. It is important to note that there is also a significant amount of coronavirus-induced disease which is clinically atypical, but no less significant to the cat and cat owner. The risk of FIP increases with increasing numbers of serologically positive cats in a household. Young cats (< 1 year of age) are at greatest risk of infection. Certain breeds (Persians) and lines within breeds appear to be predisposed to FIP subsequent to infection with FECV. No treatment has been proven to be uniformly and consistently effective. Cats may develop clinical FIP and die weeks to years after infection. The panel recognizes the inherent problems in assessing risk vs. benefit in the cat population, in part due to difficulties in assessing the owners lifestyle information about their cats. There is considerable controversy surrounding the efficacy of the FIP vaccine. Some studies demonstrate protection from disease, while others show little benefit of vaccination. Some studies demonstrate that antibody dependent enhancement of disease is a real phenomenon in certain circumstances, but there is little evidence at this time to suggest that it happens in a natural setting. These discrepant study results may be due to study methodology including the strain and dose of challenge virus and genetic predisposition of the test animals. The panel considers this to be a NON-CORE antigen with immunization protocols based on the low disease prevalence in confined populations of cats. As a result, vaccination is recommended only for cats in an at-risk group. However, the panel was split as to what constituted an at-risk group for exposure to FIP-inducing coronaviruses. A minority of the participants recommended vaccination of kittens and cats with lifestyles with significant risk of exposure to coronaviruses. The majority of the panelists chose to limit vaccine use only to specific risk situations such as households where FIP had been diagnosed. For those cats that vaccination is deemed appropriate, a foundation series of vaccinations for kittens according to recognized protocols demonstrating efficacy followed by annual booster vaccinations is recommended by the manufacturer. DOI studies have not been performed by the manufacturer.

Ringworm in cats is primarily caused by infection with Microsporum canis. Infection in the cat leads to a variety of clinical manifestations including transitory clinical disease, chronic infection with disease, and chronic infection with no clinical disease (carrier state). The comprehensive treatment and prevention program for ringworm is complex, requiring multiple treatment and management modalities. A vaccine is available that is approved for the treatment and prevention of clinical signs of disease associated with M. canis infection, but the manufacturer did not provide data to indicate prevention of or elimination of infection. The panel considers this to be a NON-CORE vaccine. Its use, according to label direction, appears reasonable when used as a part of a comprehensive M. canis control program.