ORIGINAL ARTICLE Prevalence and risk factor analysis of Haemobartonella felis in cats using direct blood smear and PCR assay Saam Torkan & Seyed Javid Aldavood & Seeyamak Mashhady Rafie & Hossein Hejazi & Darioush Shirani & Hassan Momtaz Received: 21 August 2011 /Accepted: 8 June 2012 # Springer-Verlag London Limited 2012 Abstract The present case–control study was conducted to determine the prevalence of Haemobartonella felis, study the role of its risk factors and compare the different diag- nostic tests. In order to achieve these goals, direct blood smear and single PCR assay were performed on blood samples from 90 cats (45 healthy controls and 45 sick cats). In addition, age, sex, breed, outdoor access, castration and density of living area were recorded in each group, and haematological analysis was performed on all blood sam- ples. A total of 50 and 72.2 % of cats were H. felis positive in direct blood smear and PCR, respectively. The results showed a significant difference between control and case groups regarding the quantitative variables including fever and dehydration in direct blood smear, and tachycardia, icterus, fever and dehydration in PCR (P <0.05). Castration, sex, breed, access to the outside (lifestyle) and density of cat population did not significantly affect test results. The results indicate that interactive effects of various factors (risk factors of infection) can diminish the individual spe- cific effect of each. Keywords Cat . Haemobartonella felis . Smear . PCR . Iran Introduction Haemobartonella felis, the causative agent of feline infec- tious anaemia, has recently been reclassified as a haemotro- phic mycoplasma (haemoplasma). It can cause disease as a primary pathogen or by opportunistic infection as sequelae to other diseases, particularly in those with immunosuppres- sion (Criado-Fornelio et al. 2003). The pathogen can be identified as small coccoids, rings or strings on erythrocyte membrane or free in plasma by Giemsa staining of blood smears (Carter and Chengappa 1995). This extracellular pleomorphic bacterium attaches to the surface of feline erythrocytes (Jain and Keeton 1973; Small and Ristic 1967), causing haemolytic anaemia through extravascular destruction of erythrocytes by the mononuclear phagocyte system and intravascular lysis either by direct damage to the cell membrane or an increase in osmotic fragility or both (Maede 1979). Two distinctly different haemotrophic mycoplasmas (Mycoplasma haemofelis and Mycoplasma haemominutum) have been identified in cats based on 16S rRNA gene sequen- ces. The similarities of gene sequences between these organ- isms are only 83 %. These bacterial pathogens are sometimes present in blood from mammals such as cats, mice and dogs (Neimark et al. 2002; Penzhorn et al. 2001). These bacteria can be transmitted experimentally by parenteral or oral trans- fer of small amounts of infected whole blood into susceptible cats. Intrauterine transmission can also occur, and infections S. Torkan : S. M. Rafie Department of Small Animal Internal Medicine, Science and Research Branch, Islamic Azad University, Tehran, Iran S. J. Aldavood (*) Department of Small Animal Internal Medicine, Clinical Science, Veterinary Faculty, University of Tehran, Tehran, Iran e-mail: sja@ut.ac.ir H. Hejazi Department of Parasitology and Mycology, School of Medicine, Esfahan University of Medical Science, Isfahan, Iran D. Shirani Department of Clinical Science, Faculty of Veterinary medicine, University of Tehran, Tehran, Iran H. Momtaz Department of Microbiology, Faculty of Veterinary Medicine, Shahrekord Branch, Azad University, Shahrekord, Iran Comp Clin Pathol DOI 10.1007/s00580-012-1536-0