Sero-Survey of Feline Heartworm, Feline Immunodeficiency Virus and Feline Leukemia Virus Infections in Cats
Cats can become infected with heartworm (Dirofilaria immitis) and there is emerging evidence that feline heartworm infection can cause significant pathology (Heartworm Associated Respiratory Disease or HARD) from early or transient infections. Feline Immunodeficiency Virus and Feline Leukemia Virus infections in cats can result in a broad range of clinical symptoms and can be a significant cause of death.
To better understand the prevalence of these infections in cats, a sero-survey was conducted. Serum samples were obtained from 11 clinics, shelters or IDEXX Reference Laboratories throughout the United States. All samples were collected from the population of samples submitted to each site in the course of general clinic or lab operations and were not necessarily tested for heartworm, FIV or FeLV at the site. Samples were tested for the presence of heartworm antigen, for FIV antibody, and for FeLV antigen using ELISA plate assays. A population of 19,054 samples was tested in this study. Regional results are summarized in the table below.
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This study demonstrates that cats with heartworm infections are found in all regions of the United States examined. The heartworm ELISA detects antigen in cats infected with adult female heartworms and does not detect antigens in cats with only male worm infections. Therefore, the prevalence reported in this study is likely an under-representation of the number of cats infected with heartworm. The FIV ELISA assay cannot distinguish vaccinated from naturally infected cats; therefore the prevalence reported for FIV may be an over representation of FIV infection. To the authors' knowledge, this is the largest number of cats across all regions of the United States tested in a single study for heartworm antigen. This study also demonstrates that FIV and FeLV infection continues to affect a large population of domestic cats in the United States.