Prevalence and risk factors for hemoplasmas in domestic cats naturally infected with feline immunodeficiency virus and/or feline leukemia virus in Rio de Janeiro--Brazil

The aim of this study was to determine the prevalence and risk factors for Mycoplasma haemofelis (Mhf) and 'Candidatus Mycoplasma haemominutum' (Mhm) infections in domestic cats tested for feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) with a commercial enzyme-linked immunosorbent assay (ELISA) kit. Based on serological testing, cats were grouped as i) FIV-positive (n=25); ii) FeLV-positive (n=39); iii) FIV/FeLV-positive (n=8); and iv) FIV/FeLV-negative (n=77). Complete blood counts were followed by DNA extraction, species-specific polymerase chain reaction (16S rRNA gene) for Mhf and Mhm and Southern blotting for all animals. Mhf DNA was found in 4.0, 2.6, 12.5 and 7.8% of the cats from groups i, ii, iii and iv, respectively, while 32, 5.1, 50 and 5.2% of these animals had an Mhm infection. Cats with FIV (OR=4.25, P=0.009) and both FIV and FeLV (OR=7.56, P=0.014) were at greater risk of being hemoplasma infected than retroviral-negative cats, mainly due to Mhm infection (OR=8.59, P=0.001 and OR=18.25, P=0.001, respectively). Among pure-breed cats, FIV-positive status was associated with hemoplasma infection (OR 45.0, P=0.001).     

Survival of Mycoplasma haemofelis and 'Candidatus Mycoplasma haemominutum' in blood of cats used for transfusions

Blood transfusions are commonly administered to cats; associated risks include the transmission of various infectious diseases including Mycoplasma haemofelis (Mhf) and 'Candidatus Mycoplasma haemominutum' (Mhm). Blood transfusions in citrate-phosphate-dextrose-adenine (CPDA-1) solution are commonly administered immediately or stored for up to 1 month prior to administration. It is unknown whether Mhf or Mhm survive in this solution or temperature. The purpose of this study was to determine if Mhf or Mhm remain viable after storage in CPDA-1 for varying periods of time. The results provide evidence that transmission of hemoplasmas to na?ve cats occurs after administration of infected feline blood that has been stored in CPDA-1 solution for 1h (Mhf) and 1 week (Mhm). These findings support the recommendation that cats used as blood donors be screened for Mhf and Mhm infections by polymerase chain reaction (PCR) assay prior to use.     

Use of real-time PCR to detect Mycoplasma haemofelis and 'Candidatus Mycoplasma haemominutum' in the saliva and salivary glands of haemoplasma-infected cats

Feline haemoplasma infection can cause haemolytic anaemia. The natural method of transmission of haemoplasmas between cats is currently unknown but the nature of some of the risk factors for infection suggests that saliva may act as a mode of transmission. The aim of this study was to determine if Mycoplasma haemofelis (Mhf) and 'Candidatus Mycoplasma haemominutum' (CMhm) DNAs could be amplified from saliva and salivary gland samples collected from haemoplasma-infected cats.     

The prevalence of three species of feline haemoplasmas in samples submitted to a diagnostics service as determined by three novel real-time duplex PCR assays

Three distinct species of feline haemoplasmas are recognised: Mycoplasma haemofelis (Mhf), Candidatus Mycoplasma haemominutum (CMhm) and Candidatus Mycoplasma turicensis (CMt). These species differ in pathogenicity as Mhf and CMt can be associated with anaemia whereas CMhm usually results in few clinical signs. The purpose of this study was to develop quantitative real-time PCR assays for the detection of all three feline haemoplasma species combined with an endogenous internal control and to determine the prevalence of infection, using these assays, in 1592 EDTA blood samples submitted to Langford Veterinary Diagnostics, University of Bristol for haemoplasma testing. Primers and TaqMan probes were designed against published 16S rDNA sequences. These assays were combined with a feline 28S rDNA-specific assay to produce three duplex assays. The assays detected 1-10 copies of a sequence-specific plasmid per PCR. None of the assays showed cross-reactivity with 10(6) copies of a sequence-specific plasmid from the non-target haemoplasma species. Real-time PCR was performed on all samples using the three assays. Seven samples were negative for feline 28S rDNA and were excluded from the study. Of the remaining 1585 samples, 45 (2.8%), 177 (11.2%) and 27 (1.7%) samples were positive for Mhf, CMhm and CMt, respectively, including 11 Mhf/CMhm, 10 CMhm/CMt and two Mhf/CMt dual infections and two triple infections. The results of this study demonstrate the utility of these new duplex PCR assays for the detection of haemoplasma infections. CMhm was the most common infection and CMt infections were often associated with co-infection with other haemoplasma species, especially CMhm.     

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 X 10(6)/mL to 6.9 x 10(6)/mL of blood. Sequencing of cPCR products from samples testing negative using real-time PCR identified 2 Mhp-like sequences, 1 Mhm-like 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.     

Diagnosis of feline haemoplasma infection using a real-time PCR assay

Haemobartonella felis has been reclassified within the genus Mycoplasma as Mycoplasma haemofelis and 'Candidatus Mycoplasma haemominutum', collectively referred to as the feline haemoplasmas. A total of 78 cats from the Johannesburg area that had blood samples submitted to a private veterinary laboratory were tested using a real-time polymerase chain reaction (PCR) assay able to detect and distinguish the two feline haemoplasma (basonym Haemobartonella) species. All samples had been diagnosed with haemoplasma infection by cytological examination of blood smears. Statistical analysis was performed to evaluate associations between haemoplasma status, age, and haematological and biochemical parameters. On PCR assay 43 cats (55%) were haemoplasma negative, 25 (32.1%) positive for 'Candidatus Mycoplasma haemominutum', 5 (6.4%) positive for Mycoplasma haemofelis and 5 (6.4%) positive for both species. Significant inverse correlation was found between the amount of M. haemofelis DNA present in the blood and the haematocrit value. Cats that were positive for M. haemofelis showed macrocytic regenerative anaemia, monocytosis and thrombocytopaenia. This report documents the existence of both haemoplasma species in cats in South Africa.     

Feline hemoplasmas in Switzerland: identification of a novel species, diagnosis, prevalence, and clinical importance

Two feline hemotropic mycoplasma spp. (aka hemoplasma) have previously been recognized. We recently discovered a third novel species in a cat with hemolytic anemia, designated 'Candidatus Mycoplasma turicensis', which is closely related to rodent haemoplasmas. This novel species induced anemia after experimental transmission to two SPF cats. Three quantitative real-time PCR assays were newly designed and applied to an epidemiological study surveying the Swiss pet cat population. Blood samples from 713 healthy and ill cats were analyzed. Up to 104 parameters per cat (detailed questionnaire, case history, laboratory parameters and retroviral infections) were evaluated. 'Candidatus Mycoplasma haemominutum' infection was more prevalent (8.5%) than Mycoplasma haemofelis (0.5%) and 'Candidatus Mycoplasma turicensis' (1%). Hemoplasma infections were associated with male gender, outdoor access, and old age, but not with disease or anemia. Infections were more frequently found in the South and West of Switzerland. Several hemoplasma infected cats, some acutely infected, others co-infected with FIV or FeLV, showed hemolytic anemia indicating that additional factors might play a role in the pathogenesis of the disease.     

Prevalence of feline haemotropic mycoplasmas in convenience samples of cats in Germany

The aim of this prospective study was to evaluate the prevalence of feline haemotropic mycoplasmas in Germany, to determine probable risk factors for these infections and to compare the diagnostic value of microscopic examination of blood smears to polymerase chain reaction (PCR). For the prevalence study, convenience samples (Ethylene diamine-tetraacetic acid (EDTA) blood) from 262 (64.5% male and 35.5% female) cats were included. A PCR for the detection of Mycoplasma haemofelis (MHF) and 'Candidatus Mycoplasma haemominutum' (CMH) as well as a feline leukaemia virus (FeLV)/feline immunodeficiency virus (FIV) enzyme-linked immunoassay was performed. Blood smears from 224 cats were examined and the sensitivity and specificity of the microscopic diagnosis were determined. The prevalence of CMH, MHF, and CMH/MHF co-infection was 22.5%, 4.5%, and 0.8%, respectively. CMH was significantly associated with male gender (P=0.047), older age (P=0.0015) and both FeLV (P=0.002) and FIV infections (P<0.0001). However, there was no association between the presence of anaemia and CMH/MHF infection. The respective sensitivity and specificity of the microscopic diagnosis were 10.3% and 87.1% for a CMH infection and 0.0% and 98.0% for MHF infection.     

Acute phase response to Mycoplasma haemofelis and 'Candidatus Mycoplasma haemominutum' infection in FIV-infected and non-FIV-infected cats

The pathogenicity of Haemoplasma spp. in cats varies with 'Candidatus Mycoplasma haemominutum' (CMhm) causing subclinical infection while Mycoplasma haemofelis (Mhf) often induces haemolytic anaemia. The aims of this study were to characterise the acute phase response (APR) of the cat to experimental infection with Mhf or CMhm, and to determine whether chronic feline immunodeficiency virus (FIV) infection influences this response. The acute phase proteins serum amyloid A (SAA), haptoglobin (Hp) and α-1-acid glycoprotein (AGP) concentrations were measured pre-infection and every 7-14days up to day 100 post-infection (pi) in cats infected with either Mhf or CMhm. Half of each group of cats (6/12) were chronically and subclinically infected with FIV. Marbofloxacin treatment was given on days 16-44 pi to half of the Mhf-infected cats, and on days 49-77 pi to half of the CMhm-infected cats. FIV-infected animals had significantly lower AGP concentrations, and significantly greater Hp concentrations than non-FIV-infected cats when infected with CMhm and Mhf, respectively. Both CMhm and Mhf infection were associated with significant increases in SAA concentrations, while AGP concentrations were only significantly increased by Mhf infection. Mhf-infected cats had significantly greater SAA concentrations than CMhm-infected animals. Both Mhf and CMhm infections were associated with an APR, with Mhf infection inducing a greater response. Chronic FIV infection appeared to modify the APR, which varied with the infecting Haemoplasma species.     

Occurrence of 'Candidatus Mycoplasma turicensis' infection in domestic cats in Japan

We have examined the presence of hemoplasmas, hemotropic mycoplasmas, among domestic cats (Felis catus) in Japan by using a species specific PCR, and found 'Candidatus Mycoplasma turicensis', a recently recognized hemoplasma species. A total of 60 feline blood samples collected in 2004 and 2005 were subjected to PCR amplification for the detection of Mycoplasma haemofelis, 'Candidatus Mycoplasma haemominutum' and 'Candidatus Mycoplasma turicensis'. Six blood samples collected from domestic cats were found infected with the 'Candidatus M. turicensis'. All of them are also infected with other species of hemoplasmas, M. haemofelis and/or 'Candidatus M. haemominutum'. This is the first to demonstrate 'Candidatus M. turicensis' infections among cat population in Japan.     

Diagnosis of feline haemoplasma infection in Australian cats using a real-time PCR assay

A total of 147 cats from the Sydney area of Australia that had blood samples submitted to veterinary laboratories were tested using a real-time polymerase chain reaction (PCR) assay able to detect and distinguish the two feline haemoplasma species. This sample number included two cats diagnosed with feline haemoplasma infection by routine blood smear examination. Statistical analysis was performed to evaluate associations between haemoplasma infection, age, sex, breed, haematocrit (HCT) values and anaemia status. One hundred and six cats (72.1%) were negative. Thirty-four cats (23.1%) were positive for 'Candidatus M. haemominutum', six cats (4.1%) were positive for M. haemofelis and one cat (0.7%) was positive for both species. Older, male, non-pedigree cats, with lower HCT values were more likely to be infected with 'Candidatus M. haemominutum'. Significant inverse correlation was found between the amount of M. haemofelis DNA present in the blood and the HCT value. This report documents the existence of, and prevalence of, both haemoplasma species in a sample of cats in Australia and is the first to use quantitative real-time PCR in a prevalence study for haemoplasma infection.     

Prevalences of various hemoplasma species among cats in the United States with possible hemoplasmosis

OBJECTIVE: To determine prevalences of various hemoplasma species among cats in the United States with possible hemoplasmosis and identify risk factors for and clinicopathologic abnormalities associated with infection with each species. DESIGN: Cross-sectional study. Animals-310 cats with cytologic evidence of hemoplasmosis (n = 9) or acute or regenerative anemia (309). PROCEDURES: Blood samples were tested by means of a broad-spectrum conventional PCR assay for hemoplasma DNA and by means of 3 separate species-specific real-time PCR assays for DNA from "Candidatus Mycoplasma haemominutum" (Mhm), Mycoplasma haemofelis (Mhf), and "Candidatus Mycoplasma turicensis" (Mtc). RESULTS: Overall prevalences of Mhm, Mhf, and Mtc infection were 23.2% (72/310), 4.8% (15/310), and 6.5% (20/310), respectively. Mixed infections were detected in 20 (6.5%) cats. Cats infected with hemoplasmas were more likely to be male than were uninfected cats. Infection with FeLV or FIV was significantly associated with infection with Mhf. Compared with uninfected cats, cats infected with Mhf had higher reticulocyte counts, nucleated RBC counts, and mean corpuscular volume; cats infected with Mhm had higher mean corpuscular volume; and cats infected with Mtc had higher monocyte counts. CONCLUSIONS AND CLINICAL RELEVANCE: Results supported the suggestion that these 3 hemoplasma species commonly occur among cats in the United States and that pathogenicity of the 3 species varies.     

Prevalence of DNA of Mycoplasma haemofelis, 'Candidatus Mycoplasma haemominutum,' Anaplasma phagocytophilum, and species of Bartonella, Neorickettsia, and Ehrlichia in cats used as blood donors in the United States

OBJECTIVE: To identify the prevalence of DNA of Mycoplasma haemofelis; 'Candidatus Mycoplasma haemominutum'; Anaplasma phagocytophilum; and species of Bartonella, Neorickettsia, and Ehrlichia in blood of cats used as blood donors in the United States. DESIGN: Prospective study. ANIMALS: 146 cats that were active blood donors. PROCEDURES: Environmental history was requested for each blood-donor cat from which a blood sample (mixed with EDTA) was available. Polymerase chain reaction assays capable of amplifying the DNA of the microorganisms of interest following DNA extraction from blood were performed. RESULTS: Overall, DNA of one or more of the infectious agents was detected in blood samples from 16 of 146 (11%) feline blood donors. Twenty-eight laboratory-reared cats housed in a teaching hospital had negative results for DNA of all organisms investigated. The DNA of at least 1 infectious agent was amplified from blood samples collected from 16 of 118 (13.6%) community-source cats; assay results were positive for 'Candidatus M haemominutum,' M haemofelis, or Bartonella henselae alone or in various combinations. Of the community-source cats allowed outdoors (n = 61) or with known flea exposure (44), DNA for a hemoplasma or B henselae was detected in 21.3% and 22.7%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: When community-source cats, cats allowed outdoors, or cats exposed to fleas are to be used as blood donors, they should be regularly assessed for infection with M haemofelis, 'Candidatus M haemominutum,' and Bartonella spp, and flea-control treatment should be regularly provided.     

First morphological characterization of 'Candidatus Mycoplasma turicensis' using electron microscopy

At least three haemotropic mycoplasmas have been recognized in cats: Mycoplasma haemofelis (Mhf), 'Candidatus Mycoplasma haemominutum' (CMhm) and 'Candidatus M. turicensis' (CMt). The latter was originally identified in a Swiss pet cat with haemolytic anaemia and shown to be prevalent in domestic cats and wild felids worldwide using molecular methods. So far, there has been no confirmatory morphological evidence of the existence of CMt presumably due to low blood loads during infection while CMhm has only been characterized by light microscopy with discrepant results. This study aimed to provide for the first time electron microscopic characteristics of CMt and CMhm and to compare them to Mhf. Blood samples from cats experimentally infected with CMt, CMhm and Mhf were used to determine copy numbers in blood by real-time PCR and for transmission and scanning electron microscopy. High resolution scanning electron microscopy revealed CMt and CMhm to be discoid-shaped organisms of 0.3 μm in diameter attached to red blood cells (RBCs). In transmission electron microscopy of CMt, an oval organism of about 0.25 μm with several intracellular electron dense structures was identified close to the surface of a RBC. CMhm and CMt exhibited similar morphology to Mhf but had a smaller diameter. This is the first study to provide morphological evidence of CMt thereby confirming its status as a distinct haemoplasma species, and to present electron microscopic features of CMhm.     

Detection frequency of haemoplasma infections of the domestic cat in Germany

We present epidemiological data on the frequency of infections with haemotrophic Mycoplasma spp. (feline haemoplasmas) in domestic cats in Germany. From November 2004 to October 2006 135 blood samples of anaemic patients and cats without clinical symptoms were examined with conventional and real-time PCR methods. In 15,6 % of the samples DNA of one or more haemoplasma species could be detected. 8,9 % of the samples (12 cats) were infected with "Candidatus Mycoplasma haemominutum, whereas 7,4 % (10 cats) were infected with Mycoplasma haemofelis. Out of these, one cat harboured both species.The recently described species "Candidatus Mycoplasma turicensis" was found in 2.2 % of all samples (3 cats) and was restricted to animals coinfected with M. haemofelis. No correlation could be detected between the infection with haemotrophic Mycoplasma spp. and clinical signs of anaemia or disease. Infections were significantly correlated with age, male gender or coinfections with retroviruses (FIV, FeLV). Our data indicate, that chronically infected carriers without clinical symptoms are frequent in the investigated cat populations in Germany and that the screening of blood-donors for the presence of Mycoplasma spp. infections is advisable before clinical use.     

Molecular detection of feline hemoplasmas in feral cats in Korea

The purpose of this study was to determine if Mycoplasma haemofelis, 'Candidatus Mycoplasma haemominutum' exist in Korea. Three hundreds and thirty one feral cats were evaluated by using PCR assay targeting 16S rRNA gene sequence. Fourteen cats (4.2%) were positive for M. haemofelis, 34 cats (10.3%) were positive for 'Candidatus M. haemominutum' and 18 cats (5.4%) were positive for both species. Partial 16S rRNA gene sequences were closely (>98%) related to those from other countries. This is the first molecular detection of feline hemoplasmas in Korea.     

Humoral immune response to a recombinant hemoplasma antigen in experimental 'Candidatus Mycoplasma turicensis' infection

'Candidatus Mycoplasma turicensis' is a feline hemoplasma species that was isolated in a cat with hemolytic anemia. PCR has been widely used to investigate and diagnose 'Candidatus Mycoplasma turicensis' infection, but so far, little is known about the humoral immune response in infected cats. Recently, enzyme-linked immunosorbent assays (ELISA) were developed to monitor anti-feline hemoplasma antibodies. The aim of the present study was to investigate the humoral immune response in cats experimentally infected with 'Candidatus Mycoplasma turicensis' and to monitor the influence of the pre-administration of methylprednisolone and subsequent antibiotic treatment. Serum and plasma samples from 15 specified pathogen-free cats infected with 'Candidatus Mycoplasma turicensis' were analyzed by ELISA. Seroconversion was demonstrated in all cats, and the antibodies remained detectable until the end of the study (up to 100 weeks post-exposure). In some cats, the ELISA seemed more sensitive and better able to demonstrate exposure to 'Candidatus Mycoplasma turicensis' than PCR. The peak antibody level occurred after the peak of the bacterial blood loads. The methylprednisolone administrations were associated with increased antibody levels, while antibiotic treatment, particularly with doxycycline, resulted in a decrease in antibody levels. Additionally, preliminary data indicated that three of four seropositive cats were protected from bacteremia after a subsequent challenge. In conclusion, the ELISA was found to be a useful tool to investigate the humoral immune response in hemoplasma-infected cats and a desirable addition to PCR to study the pathogenesis of hemoplasma infections.     

Detection of mixed infections with "Candidatus Mycoplasma haemominutum" and Mycoplasma haemofelis using real-time TaqMan polymerase chain reaction.

The objective of this study was to evaluate the use of real-time TaqMan PCR assays for detection of coinfections with "Candidatus Mycoplasma haemominutum" (Mhm), and Mycoplasma haemofelis (Mhf), in vitro and over time in experimentally infected cats. First, the ability of each real-time PCR assay to detect and quantify mixed infections was determined in vitro by testing mixtures of plasmids containing Mhm and Mhf 16S rDNA with each assay. Subsequently, 4 specific pathogen-free (SPF) cats, 2 of which were splenectomized, were inoculated with blood from a cat infected with both Mhm and Mhf. Sixteen blood samples were then collected from each cat over a 55-day period. Each of the 64 postinoculation samples was tested using both conventional polymerase chain reaction (cPCR) and real-time PCR for the 16S rRNA gene of each organism. When applied to mixtures of plasmid DNA from each species, the results of quantitation with each of the real-time PCR assays approximately reflected the number of plasmid copies present. Forty-nine of 64 post-inoculation samples (77%) were positive using both cPCR and real-time PCR, 4 (6%) were positive using cPCR only, and 3 (5%) were positive using real-time PCR only. Both organisms were detected in 23 samples using real-time PCR. Mixed infections were not detected using cPCR. The size of the corresponding cPCR products suggested infection with Mhm in 4 and Mhf in 18 of these samples. The use of multiple separate real-time PCR assays rather than cPCR alone should thus be considered for epidemiologic studies of hemoplasmosis in cats.     

Molecular investigation of transplacental and vector-borne transmission of bovine haemoplasmas

The present study was carried out in a herd with concurrent infections of Mycoplasma wenyonii and 'Candidatus M. haemobos', to investigate if transplacental and/or vector-borne transmission is possible for one or both bovine haemoplasma species. For this purpose blood samples were collected from 38 mother animals and their newborn calves; as well as from 17 uninseminated cows twice three months apart. In addition, 311 mosquitoes and blood-sucking flies (Diptera: Culicidae, Tabanidae, Muscidae) were cought near the animals. DNA was extracted from all samples, followed by real-time PCR analysis. In 10.5% of neonate calves, that were born to cows harbouring both haemoplasmas, M. wenyonii and/or 'Candidatus M. haemobos' positivity was detected. Copy numbers in positive samples from cows and their calves indicated that - in comparison with M. wenyonii - 'Candidatus M. haemobos'-bacteraemia had usually lower levels. In samples of uninseminated cows the rate of infection with the latter species decreased. These findings may explain why M. wenyonii was significantly more frequently detected in blood-sucking flies, than 'Candidatus M. haemobos'. In conclusion, molecular evidence is provided for the first time on the transplacental transmission of bovine haemoplasmas. Regarding their spread by blood-sucking arthropods, new potential vectors were identified, i.e. the horn fly (Haematobia irritans), the stable fly (Stomoxys calcitrans) and two species of horse flies (Tabanus bovinus, T. bromius).     

Evaluation of experimental transmission of Candidatus Mycoplasma haemominutum and Mycoplasma haemofelis by Ctenocephalides felis to cats

OBJECTIVE: To determine whether Ctenocephalides felis can transmit Mycoplasma haemofelis (Mhf) and Candidatus Mycoplasma haemominutum (Mhm) through hematophagous activity between cats. ANIMALS: 11 cats. PROCEDURE: 2 cats were carriers of either Mhf or Mhm. Nine cats had negative results via polymerase chain reaction (PCR) assay for Mhf and Mhm DNA; 3 of those cats were infected from the chronic carriers via i.v. inoculation of blood. At the time of maximum organism count for each of the Mycoplasma spp, 1 chamber containing 100 C felis was bandaged to the amplifier cats. Five days later, fleas, feces, larvae, or eggs from each chamber were analyzed for Mycoplasma spp DNA. Viable fleas from the chambers were allocated into new chambers (3 Mhm and 6 Mhf) and attached to na?ve cats for 5 days. Cats were monitored daily for clinical signs and weekly via CBC and PCR assay for infection with Mhf or Mhm for a minimum of 8 weeks. RESULTS: Uptake of Mhf and Mhm DNA into fleas, feces, and, potentially, eggs and larvae was detected. Of the na?ve cats fed on by Mhf-infected fleas, 1 cat transiently yielded positive PCR assay results for Mhf on 1 sampling date without clinical or hematologic changes consistent with Mhf infection. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that hematophagous transfer of Mhm and Mhf into fleas occurred and that C felis is a possible vector for Mhf via hematophagous activity.