Use of conventional and real-time polymerase chain reaction to determine the epidemiology of hemoplasma infections in anemic and nonanemic cats

Background: The goals of this study were to develop and apply conventional (c) and real-time TaqMan polymerase chain reaction (PCR) assays for Mycoplasma haemofelis (Mhf), 'Candidatus Mycoplasma haematoparvum' (Mhp), and 'Candidatus Mycoplasma haemominutum' (Mhm) to blood samples of cats to determine the epidemiology of these infections in cats. Hypothesis: Cats are infected with > 2 hemoplasma species, and organism load correlates with disease induced by these organisms. Animals: Blood samples from 263 anemic and nonanemic cats were used. Methods: A retrospective study was conducted. Results: Forty-seven (18%) samples were positive. Three samples (1%) yielded 170 base pair cPCR products, 1 of which was positive for Mhf using real-time PCR. Forty-four samples (17%) yielded 193 base pair cPCR products, 40 of which were positive for Mhm using real-time PCR. Organism loads ranged from 375 × 10 ⁶/mL to 6.9 × 10 ⁶/mL of blood. Sequencing of cPCR products from samples testing negative using real-time PCR identified 2 Mhp-like sequences, 1 Mhm-Yike sequence, and 1 sequence resembling 'Candidatus Mycoplasma turicensis.' Cats infected with Mhm were less likely to be anemic than uninfected cats. Older age, outdoor exposure, feline immunodeficiency virus (FIV) seropositivity, cutaneous squamous cell carcinoma (SCC), and stomatitis were associated with Mhm infection. Cats from the Sacramento Valley were more often infected with Mhm than cats from the San Francisco bay area. Conclusions and Clinical Importance: Cats may be infected with 4 hemoplasma species. The association between Mhm infection, FIV, and SCC may reflect outdoor roaming status of infected cats. The clustered distribution of infection suggests an arthropod vector in transmission.