Feline respiratory tract disease in Louisiana.

An investigation of feline respiratory tract disease (FRD) was made involving 65 affected cats (group 1) and 65 control cats (group 2) matched for age, sex, and residence. Feline calicivirus strains (FCV), feline herpesvirus-1 (FHV-1), or both, were isolated from 59% of group 1 cats and from 7% of group 2 cats. Isolation of these viruses showed a significantly greater (P < 0.05) relative risk for group 1 cats. Virus isolations were three times more frequent from males than from females older than 1 year (both groups), but were equally distributed between males and females younger than 1 year. Bacteria and fungi had a secondary role in both FCV- and FHV-1 associated FRD. Intestinal infections of Ancylostoma spp, Dipylidium caninum, and Toxocara cati were diagnosed more frequently in group 1 cats than in control (group 2). Paragonimus kellicotti was diagnosed in 3 group 1 cats, Taenia taeniaeformis in 1 group 1 cat, Isospora rivolta in 1 group 1 cat, and Giardia cati in 1 control cat. The present study supports the current concept of a primary viral cause for development of FRD.