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

Prevalence of Hemoplasma spp. positivity in potential feline blood donors and study of the association with selected clinical variables

BACKGROUND

Hemotropic mycoplasmas, hemoplasmas, are epi-erythrocytic parasitic bacteria that can be transmitted through blood transfusion.

OBJECTIVES

To study the prevalence of hemoplasma infection of potential feline blood donors and investigate the association between Hemoplasma spp. quantitative polymerase chain reaction (qPCR) positivity in blood units and selected variables.

ANIMALS

Seven thousand five hundred seventy-three blood units from 4121 privately-owned potential donor cats.

METHODS

Retrospective observational cross-sectional study. The Banco Sangue Animal (BSA)-Animal Blood Bank medical database was reviewed for all feline donations performed in 2022 in Portugal, Spain, and Belgium. Baseline characteristics and results of blood-borne pathogens screening tests were extracted from the medical records.

RESULTS

Two hundred twelve of 4034 Portuguese donor cats and 2 of 70 Spanish donor cats tested positive for Hemoplasma spp. qPCR in 2022 leading to an overall estimated prevalence of 5.2% (95% CI: 4.5%-5.9%) in potential blood donors. Using multivariable generalized estimation equation models, Hemoplasma spp. qPCR was more often positive among blood units issued from male cats (OR = 1.9, 95% CI: 1.4-2.6, P < .0001), units positive for FeLV (OR = 2.8, 95% CI: 1.4-5.6, P = .0023), and units collected in winter months (OR = 2.5, 95% CI: 1.7-3.6, P < .0001).

CONCLUSIONS AND CLINICAL IMPORTANCE

This study underscores the importance of Hemoplasma spp. and other relevant blood-borne pathogens screening at every donation. Implementing stringent screening protocols is crucial to mitigate the risk of hemoplasma transmission via blood transfusions, thereby safeguarding the health and welfare of cats receiving transfusions.

Associations between presence of Bartonella species deoxyribonucleic acid and complete blood cell count and serum biochemical changes in client-owned cats

Background

Infection with Bartonella species is common in cats but reported effects of bacteremia on laboratory variables differ.

Objectives

Evaluate for associations between Bartonella bacteremia and CBC and serum biochemical changes in sick and healthy cats throughout the United States.

Animals

A total of 3964 client‐owned cats.

Methods

Retrospective cohort study using submissions to a commercial laboratory between 2011 and 2017. Serum biochemistry and CBC abnormalities (categorized as above or below reference intervals), age, and location (high‐ or low‐risk state for Ctenocephalides felis) in presumed healthy and sick cats were evaluated for associations with presence of Bartonella spp. DNA, detected by PCR. Univariate and multivariable logistic regression analyses were performed.

Results

Bartonella spp. DNA was amplified from 127 (3.2%) of 3964 cats; 126 (99.2%) of 127 were from high flea risk states and 121 (95.3%) of 127 were presumed sick. Fever of unknown origin was the most common PCR panel requested. In the multivariable analysis, neutrophilia, decreased ALP activity, clinical status (presumed sick), and young age (≤2 years) each were positively associated whereas neutropenia and hyperproteinemia both were negatively associated with Bartonella spp. bacteremia. Presence of Bartonella spp. DNA had no association with test results for other infectious disease agents.

Conclusions and Clinical Importance

In both healthy and sick cats, active Bartonella infections had minimal association with clinically relevant laboratory abnormalities. However, based on these results, in areas considered high risk for C. felis, active infection with Bartonella spp. is a reasonable differential diagnosis for cats presented with unexplained fever and neutrophilia, particularly if the cat is young.

Transfusion transmissible pathogens are prevalent in healthy cats eligible to become blood donors

OBJECTIVES

This study aims to determine the prevalence of subclinical infectious agents considered core pathogens for worldwide screening in healthy, client-owned, indoor cats eligible to become blood donors in Spain and Portugal.

MATERIALS AND METHODS

Blood samples of healthy, indoor, domestic cats selected to be potential blood donors were tested for feline leukaemia virus antigens, feline immunodeficiency virus antibodies and polymerase chain reactions for Mycoplasma haemofelis, Candidatus Mycoplasma haemominutum, Candidatus Mycoplasma turicensis, feline leukaemia virus provirus, Leishmania spp. and Bartonella spp. Not all donors were tested for all agents.

RESULTS

Overall, 5105 healthy indoor cats were tested and 8.1% (414/5105) had at least one subclinical infectious agent that is transmissible through blood product transfusion. 1.5% (77/5105) were positive for feline leukaemia virus antigens and 2.9% (148/5105) were positive for feline immunodeficiency virus antibodies, therefore they were excluded as donors. The overall prevalence of haemoplasmas in feline leukaemia virus and feline immunodeficiency virus SNAP-negative feline blood donors was 3.7% (181/4880) [1.3% (63/4880) were positive for Mycoplasma haemofelis; 2.3% (112/4880) to Candidatus Mycoplasma haemominutum and 0.12% (6/4880) to Candidatus Mycoplasma turicensis]. The prevalence of feline leukaemia provirus was 5.2% (9/173) and of Bartonella spp. was 0.2% (2/1122). None of the 173 cats were positive for Leishmania spp.

CLINICAL SIGNIFICANCE

The prevalence of many transfusion transmissible pathogens was relatively high in this healthy, client-owned, indoor cats eligible to become blood donors. Performing an extended screening panel that includes at least polymerase chain reactions for Mycoplasma haemofelis, Candidatus Mycoplasma haemominutum, Candidatus Mycoplasma turicensis, feline leukaemia virus provirus, and Bartonella spp., in addition to feline leukaemia virus antigens and feline immunodeficiency virus antibodies, is recommended in pet blood banks from analogous regions.

New findings associated with presumptive systemic lupus erythematosus in a kitten

CASE SUMMARY

An 8-month-old neutered male domestic shorthair kitten was examined for anorexia, lethargy and palatine ulcers. Systemic lupus erythematosus (SLE) was suspected based on a positive antinuclear antibody (ANA) titer and six manifestations of autoimmunity: fever, paronychia, oral ulcers, proteinuria, thrombocytopenia and leukopenia. Mastocytemia was observed on the blood smear. Although the clinical presentation of this case meets the classification criteria for SLE in humans, tick-borne disease and histopathology evaluation of the oral and cutaneous lesions would have been necessary to support a definite diagnosis of SLE. Baseline ANA titration was performed in two laboratories with conflicting results, which may reflect substrate differences used for the titration, but a false-positive result cannot be excluded. The cat received prednisolone and all clinical and laboratory abnormalities resolved after two months of treatment. Subsequent ANA titers remained positive and were not correlated to the patient's clinical progression.

RELEVANCE AND NOVEL INFORMATION

This report describes new findings associated with a presumptive diagnosis of SLE in a kitten, highlighting that SLE may not be ruled out even in young cats and may be associated with mastocytemia. ANA titration is part of the initial diagnostic work-up of SLE but is a non-specific test and discrepancies can be observed between laboratories. The titration of more specific antibodies such as those used in humans would be helpful to diagnose SLE. ANA titration may not correlate with clinical activity of SLE; hence, the interest of an ANA titer follow-up to establish disease control warrants further investigation.

Anaplasma phagocytophilum infection in cats: A literature review to raise clinical awareness

PRACTICAL RELEVANCE

Granulocytic anaplasmosis is a disease in humans and animals caused by the Gram-negative bacterium Anaplasma phagocytophilum within the family Anaplasmataceae. The pathogen is transmitted by ticks of the Ixodes species. Infections with A phagocytophilum have often been described in dogs but reports on natural infections in cats are rare. An infection with A phagocytophilum should be considered as a differential diagnosis in cats if the history reveals tick infestation and/or outdoor access in combination with the relevant clinical signs.

GLOBAL IMPORTANCE

A phagocytophilum is also important in human medicine because of its zoonotic potential. Due to the risk of vector-borne infections for both feline and public health, cats should be protected with ectoparasiticides, especially in endemic areas.

AIM

The aim of this review is to give an overview of the published data and summarise the epidemiology, pathogenesis, diagnosis, clinical signs and therapy of feline granulocytic anaplasmosis. As clinical signs are vague and non-specific, this review aims to raise awareness of A phagocytophilum infection, both among clinicians, so that they consider testing potentially exposed cats, and scientists, in order to prompt further research.

EVIDENCE BASE

Sixteen publications describing 55 cats have been reviewed. Thirty-four cats were well diagnosed based on guidelines of the European Advisory Board on Cat Diseases and blood analyses were performed to varying extents for these cats. Because of the limited number of studies and a lack of knowledge in cats, clinical signs and blood analyses are compared with available data in dogs.

Hemotropic mycoplasmas in naturally infected cats in Northeastern Brazil

This study aimed to determine the prevalence, factors associated, laboratory findings (with and without coinfection by retroviruses) among naturally infected cats by hemoplasmas in northeastern Brazil. For convenience, 200 domesticated and healthy cats were selected. Blood samples were taken to perform complete blood counts, serum biochemical, immunochromatography tests and nPCR for FIV and FeLV, and PCR for hemoplasma recognition. An interview was conducted to determine the factors associated with hemoplasmas. A total of 71/200 (35.5%) cats were positive for at least one hemoplasma species. Isolated infections were observed in 12,5% for 'Candidatus Mycoplasma haemominutum', 12% for Mycoplasma haemofelis and 3% for 'Candidatus Mycoplasma turicensis'. Regarding copositivity, 2% of the animals were positive for M. haemofelis and 'Candidatus Mycoplasma haemominutum', 1.5% for M. haemofelis and 'Candidatus Mycoplasma turicensis', and 4.5% for ' Candidatus Mycoplasma haemominutum' and 'Candidatus Mycoplasma turicensis'. No clinical and laboratory changes were observed in the animals that were concomitantly positive for retroviruses and hemoplasmas. Periurban region cats were more likely to be infected by M. haemofelis, while contact with other cats and infection by ' Candidatus Mycoplasma turicensis' were associated with 'Candidatus Mycoplasma haemominutum'. This study indicates that infection by hemoplasmas is a common find in cats from northeastern Brazil.

Comparison of three blood transfusion guidelines applied to 31 feline donors to minimise the risk of transfusion-transmissible infections

Objectives The increased demand for animal blood transfusions creates the need for an adequate number of donors. At the same time, a high level of blood safety must be guaranteed and different guidelines (GLs) deal with this topic. The aim of this study was to evaluate the appropriateness of different GLs in preventing transfusion-transmissible infections (TTI) in Italian feline blood donors. Methods Blood samples were collected from 31 cats enrolled as blood donors by the owners' voluntary choice over a period of approximately 1 year. Possible risk factors for TTI were recorded. Based on Italian, European and American GLs, specific TTI, including haemoplasmas, feline leukaemia virus (FeLV), feline immunodeficiency virus (FIV), Anaplasma phagocytophilum, Ehrlichia species, Bartonella species, Babesia species, Theileria species, Cytauxzoon species, Leishmania donovani sensu lato and feline coronavirus (FCoV), were screened. Rapid antigen and serological tests and biomolecular investigations (PCR) were used. Several PCR protocols for haemoplasma and FeLV DNA were compared. Results The presence of at least one recognised risk factor for TTI was reported in all cats. Results for FIV and FeLV infections were negative using rapid tests, whereas five (16.1%) cats were positive for FCoV antibodies. Four (12.9%) cats were PCR positive for haemoplasma DNA and one (3.2%) for FeLV provirus, the latter being positive only using the most sensitive PCR protocol applied. Other TTI were not detected using PCR. Conclusions and relevance Blood safety increases by combining the recommendations of different GLs. To reduce the risk of TTI, sensitive tests are needed and the choice of the best protocol is a critical step in improving blood safety. The cost and time of the screening procedures may be reduced if appropriate tests are selected. To this end, the GLs should include appropriate recruitment protocols and questionnaire-based risk profiles to identify suitable donors.

Assessment of the ability of Aedes species mosquitoes to transmit feline Mycoplasma haemofelis and ' Candidatus Mycoplasma haemominutum'

Objectives The objective of this study was to evaluate wild-caught mosquitoes for evidence of hemotropic Mycoplasma species DNA and to determine whether the feline hemoplasmas, Mycoplasma haemofelis (Mhf) and ' Candidatus Mycoplasma haemominutum' (Mhm), can be transmitted by Aedes aegypti mosquitoes in a laboratory setting. Methods Wild-caught mosquito pools (50 mosquitoes per pool, 84 pools) utilized in routine public health department disease surveillance programs were tested for hemotropic Mycoplasma species DNA using PCR with primers designed to amplify all known hemoplasmas. Additionally, mosquitoes were trapped in the vicinity of known feral cat colonies, pooled (50 mosquitoes per pool) and tested (84 pools). Purpose-bred cats housed in a research facility were infected with Mhf or Mhm and then colonized laboratory A aegypti were fed upon the bacteremic cats. After a 7 day incubation period, mosquitoes previously fed on infected cats were allowed to feed again on naive cats, which were monitored for bacteremia for 10 weeks. Results Mycoplasma wenyonii DNA was confirmed in one wild-caught mosquito pool by DNA sequencing. While 7% of cats tested in feral colonies were hemoplasma positive, none of the mosquitoes trapped near colonies were positive. Hemoplasma DNA was amplified from A aegypti by PCR immediately after the infectious blood meal, but DNA was not detected at 7 and 14 days after feeding. Although evidence for uptake of organisms existed, hemoplasma DNA was not amplified from the experimentally infested cats in the 10 week observation period. Conclusions and relevance While wild-caught mosquitoes contained hemoplasma DNA and laboratory reared A aegypti mosquitoes take up hemoplasmas during the blood meal, there was no evidence of biologic transmission in this model.

Update on Canine and Feline Blood Donor Screening for Blood-Borne Pathogens

An update on the 2005 American College of Veterinary Internal Medicine (ACVIM) Consensus Statement on blood donor infectious disease screening was presented at the 2015 ACVIM Forum in Indianapolis, Indiana, followed by panel and audience discussion. The updated consensus statement is presented below. The consensus statement aims to provide guidance on appropriate blood‐borne pathogen testing for canine and feline blood donors in North America.

Prevalence and phylogenetic analysis of haemoplasmas from cats infected with multiple species

Mycoplasma haemofelis (Mhf), ‘Candidatus Mycoplasma haemominutum’ (CMhm) and ‘Candidatus Mycoplasma turicensis’ (CMt) are agents of feline haemoplasmosis and can induce anaemia in cats. This study aimed to determine the prevalence and phylogeny of haemoplasma species in cats from Brazil's capital and surrounding areas, and whether correlation with haematological abnormalities existed. Feline haemoplasmas were found in 13.8% of 432 cats. CMhm was the most prevalent species (in 13.8% of cats), followed by Mhf (11.1%) and CMt (4.4%). Over 80% of haemoplasma-infected cats harboured two or more feline haemoplasma species: 7.1% of cats were co-infected with Mhf/CMhm, 0.4% with CMhm/CMt and 3.9% with Mhf/CMhm/CMt. Male gender was significantly associated with haemoplasma infections. No association was found between qPCR haemoplasma status and haematological variables, however CMhm relative copy numbers were correlated with red blood cell (RBC) numbers and packed cell volume (PCV). Haemoplasma 16S rRNA gene sequences (> 1 Kb) were derived from co-infected cats using novel haemoplasma species-specific primers. This allowed 16S rRNA gene sequences to be obtained despite the high level of co-infection, which precluded the use of universal 16S rRNA gene primers. Within each species, the Mhf, CMhm and CMt sequences showed > 99.8%, > 98.5% and > 98.8% identity, respectively. The Mhf, CMhm and CMt sequences showed > 99.2%, > 98.4% and > 97.8% identity, respectively, with GenBank sequences. Phylogenetic analysis showed all Mhf sequences to reside in a single clade, whereas the CMhm and CMt sequences each grouped into three distinct subclades. These phylogeny findings suggest the existence of different CMhm and CMt strains.

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Over 80% of haemoplasma-infected cats had more than one haemoplasma species.

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The use of species-specific primers allowed derivation of 16S rDNA sequences from co-infected cats.

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Male gender was significantly associated with haemoplasma infection.

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Phylogenetic analysis showed subclade formation within two of the haemoplasma species sequences.

Blood transfusion in cats: ABCD guidelines for minimising risks of infectious iatrogenic complications

OVERVIEW

The availability of blood components has increased the number of indications for transfusing cats, and fresh whole blood is readily accessible to clinicians because it can be taken from in-house donor cats or 'volunteer' feline blood donors. A certain amount of risk remains to the recipient cat, as immediate or delayed adverse reactions can occur during or after transfusion, related to immunemediated mechanisms. This article, however, focuses on adverse events caused by infectious agents, which may originate either from contamination of blood following incorrect collection, storage or transfusion, or from transfusion of contaminated blood obtained from an infected donor.

PREVENTION OF BLOOD CONTAMINATION

In cats, blood cannot be collected through a closed system and, therefore, collection of donor blood requires a multi-step manipulation of syringes and other devices. It is crucial that each step of the procedure is performed under the strictest aseptic conditions and that bacterial contamination of blood bags is prevented, as bacterial endotoxins can cause an immediate febrile reaction or even fatal shock in the recipient cat.

PREVENTION OF DISEASE TRANSMISSION

With a view to preventing transmission of blood-borne infectious diseases, the American College of Veterinary Internal Medicine has adopted basic criteria for selecting pathogens to be tested for in donor pets. The worldwide core screening panel for donor cats includes feline leukaemia virus, feline immunodeficiency virus, Bartonella species and feline haemoplasma. The list should be adapted to the local epidemiological situation concerning other vector-borne feline infections. The most practical, rapid and inexpensive measure to reduce transfusion risk is to check the risk profile of donor cats on the basis of a written questionnaire. Blood transfusion can never, however, be considered entirely safe.

Molecular detection of haemotropic Mycoplasma species in urban and rural cats from Portugal

OBJECTIVES

The aim of the present study was to evaluate the prevalence of haemoplasma infection in cats in Portugal and to assess risk factors for infection.

METHODS

Real-time polymerase chain reaction techniques were used to assess 236 urban and rural cats from central and southern Portugal.

RESULTS

The overall prevalence of haemoplasma in the target population was 27.1% (64/236), with individual species' prevalences as follows: 17.8% (42/236) 'Candidatus Mycoplasma haemominutum' (CMhm), 14.4% (34/236) Mycoplasma haemofelis (Mhf) and only 5.9% (14/236) 'Candidatus Mycoplasma turicensis' (CMt). Multiple infections were detected in 8.1% (19/236) of the samples, with triple and double infections with Mhf and CMhm being most commonly detected (5.9% [14/236] of cats). Haemoplasma infection was significantly higher in shelter cats (P = 0.015) than in cats with other lifestyles (eg, free-roaming/house pet/blood donors). Haemoplasma prevalence was also higher in cats with feline immunodeficiency virus infection (FIV; P = 0.011). Although sex was not significantly associated with haemoplasma infection (P = 0.050), CMt was predominantly found in males (P = 0.032). Also, the presence of haemoplasma multiple infections was statistically associated with being in a shelter (P = 0.021), male (P = 0.057) and with FIV co-infection (P = 0.004). No evidence of an association between haemoplasma infection and geographical location, age or feline leukaemia virus co-infection was found.

CONCLUSIONS AND RELEVANCE

The results obtained in our study are consistent with the documented worldwide prevalence of feline haemoplasma infections, suggesting that the three main feline haemoplasma species are common in Portugal.

Molecular study on selected vector-borne infections in urban stray colony cats in northern Italy

Feline vector-borne diseases can be caused by a range of pathogens transmitted by arthropods. Many of these infections have zoonotic implications, and stray cats are potential sentinels for human and pet health. This study investigated the prevalence of selected vector-borne infections in stray colony cats in Milan. Blood samples from 260 stray cats were evaluated, using conventional polymerase chain reaction tests (cPCRs), for the presence of DNA associated with Rickettsia species, Anaplasma phagocytophilum and Ehrlichia species. Positive cPCR results occurred in 127/260 subjects (48.9%; 95% confidence interval [CI] = 40.7-58.1), with a prevalence of 31.9% (83/260, 95% CI = 25.4-39.6) for Rickettsia species, 17.7% (46/260, 95% CI= 13.0-23.6) for A phagocytophilum, and 5.4% (14/260, 95% CI = 2.9-9.0) for Ehrlichia species. There was no statistical association between a positive PCR test for vector-borne infections surveyed and colony location, age, gender, body condition score or complete blood count abnormalities, nor feline immunodeficiency virus, feline leukaemia virus or Toxoplasma gondii status. The only variable linked to positive PCR results was detection of signs of ocular infection and PCR positivity for Rickettsia species (P = 0.04, odds ratio [OR] = 2.2, 95% CI = 1.1-4.4, P = 0.02). There is a significant prevalence of vector-borne infections with zoonotic potential in urban stray cats in Milan. Thus, dogs and pet cats with outdoor access should be monitored and treated for ectoparasites on a regular basis to minimise risks of disease and the potential transmission of zoonotic agents to people.

Prevalence of haemoplasma infections in stray cats in northern Italy

This study investigated the prevalence of feline haemoplasma infections in a number of stray cat colonies in Milan, Northern Italy. Blood samples from 260 stray cats were evaluated, with conventional PCR, for the presence of DNA associated with Mycoplasma haemofelis (Mhf) and "Candidatus Mycoplasma haemominutum" (CMhm). Odd ratios (OR) were calculated to identify risk factors for haemoplasma infections. PCR was positive in 86 out of 260 subjects (33.1%), with a prevalence of 10.8% (28/260 cats) for Mhf and 22.3% (58/260 cats) for CMhm. No coinfections were registered. There were significant associations between infections and season of sampling, that is, a negative association between winter sampling and a haemoplasma positive status (OR = 0.29, P = 0.001), or CMhm positive status (OR = 0.29, P = 0.01). Haemoplasma infections are common in stray cats in Milan. Thus, domestic cats with outdoor access should be routinely monitored and treated for ectoparasites to minimize risks of disease acquisition. Moreover, as these infections are transmitted via blood, feline blood donors from this area should be screened by PCR and preferably be drawn from a population of indoor cats regularly treated for fleas.

Transfusion medicine in small animals

This article reviews the use of transfusion medicine in veterinary medicine and discusses current research regarding donor screening and component therapy. Typing and crossmatching methodologies are discussed. Available components, potential uses, and controversies in treatment are also discussed.

Haemoplasmas: lessons learnt from cats

The haemotropic mycoplasmas (haemoplasmas) are a group of bacteria that can induce anaemia in a wide variety of mammals, including domestic cats and wild felids. Different feline haemoplasma species of varying pathogenicity exist, with the more pathogenic Mycoplasma haemofelis (Mhf) capable of inducing severe haemolytic anaemia, whilst 'Candidatus Mycoplasma haemominutum' (CMhm) and 'Candidatus Mycoplasma turicensis' (CMt) are infrequently associated with clinical disease. Chronic haemoplasma infections are common and cats are frequently infected by two or more haemoplasmas, complicating the clinical picture. The natural route of transmission of haemoplasma infection between cats has not yet been determined; however, experimental transmission has been demonstrated via both oral and parenteral administration of infected blood. To date the haemoplasmas have been unable to be cultured in vitro, and accurate diagnosis is currently reliant on detection of bacterial DNA using PCR assays. Treatment of clinical haemoplasmosis is focussed on supportive care in combination with empirical treatment with antimicrobials (tetracyclines or fluoroquinolones). A significant number of asymptomatic cats are positive for haemoplasma infection. These cats may play a role in the maintenance of haemoplasma infection within a population, and need to be considered when choosing potential blood donors. Use of PCR assays has provided an accurate method of diagnosing haemoplasma infection and quantifying response to therapy, including in non-feline host animals, as presumed zoonotic haemoplasma infections are now being documented. Recent advances in genome sequencing techniques have allowed the whole genome sequences of the feline haemoplasmas Mhf and CMhm to be derived, as well as a number of non-feline haemoplasma species. These data have aided the identification of antigens for use in the development of serological tests, allowed the proteomic study of haemoplasmas and provided clues as to how the haemoplasmas can persist within the host. Future areas of study include investigation of their zoonotic potential, mechanisms of immune system evasion and transmission of these emerging pathogens.

"Candidatus Mycoplasma haemomacaque" and Bartonella quintana bacteremia in cynomolgus monkeys

Here, we report latent infections with Bartonella quintana and a hemotropic Mycoplasma sp. in a research colony of cynomolgus monkeys (Macaca fascicularis). Sequence alignments, evolutionary analysis, and signature nucleotide sequence motifs of the hemotropic Mycoplasma 16S rRNA and RNase P genes indicate the presence of a novel organism.

Genome of Mycoplasma haemofelis, unraveling its strategies for survival and persistence

Mycoplasma haemofelis is a mycoplasmal pathogen (hemoplasma) that attaches to the host's erythrocytes. Distributed worldwide, it has a significant impact on the health of cats causing acute disease and, despite treatment, establishing chronic infection. It might also have a role as a zoonotic agent, especially in immunocompromised patients. Whole genome sequencing and analyses of M. haemofelis strain Ohio2 was undertaken as a step toward understanding its survival and persistence. Metabolic pathways are reduced, relying on the host to supply many of the nutrients and metabolites needed for survival. M. haemofelis must import glucose for ATP generation and ribose derivates for RNA/DNA synthesis. Hypoxanthine, adenine, guanine, uracil and CMP are scavenged from the environment to support purine and pyrimidine synthesis. In addition, nicotinamide, amino acids and any vitamins needed for growth, must be acquired from its environment. The core proteome of M. haemofelis contains an abundance of paralogous gene families, corresponding to 70.6% of all the CDSs. This "paralog pool" is a rich source of different antigenic epitopes that can be varied to elude the host's immune system and establish chronic infection. M. haemofelis also appears to be capable of phase variation, which is particularly relevant to the cyclic bacteremia and persistence, characteristics of the infection in the cat. The data generated herein should be of great use for understanding the mechanisms of M. haemofelis infection. Further, it will provide new insights into its pathogenicity and clues needed to formulate media to support the in vitro cultivation of M. haemofelis.

Prevalence of Bartonella species, haemoplasmas and Toxoplasma gondii in cats in Scotland

The objective of this study was to determine the prevalence rates for select infectious agents of cats presented to the Royal (Dick) School of Veterinary Studies at the University of Edinburgh, Scotland. Whole blood, serum, and oral mucosal and nail bed swabs were collected. While Ehrlichia species, Anaplasma species or Rickettsia felis DNA were not amplified from any cat, 44.2% of the cats had evidence of infection or exposure to either a Bartonella species (15.3% were seropositive and 5.8% polymerase chain reaction (PCR) positive), a haemoplasma (28.6% PCR positive), and/or Toxoplasma gondii (19.2% seropositive). No Bartonella species DNA was amplified from the nail or oral mucosal swabs despite a 5.8% amplification rate from the blood samples. This finding likely reflects the absence of Ctenocephalides felis infection from our study population, as this organism is a key component for Bartonella species translocation in cats. The results from this study support the use of flea control products to lessen exposure of cats (and people) to Bartonella species and support discouraging the feeding of raw meat to cats and preventing them from hunting to lessen T gondii infection.

Ehrlichiosis and anaplasmosis in dogs and cats

In the time since canine ehrlichiosis due to Ehrlichia canis was first described in 1935 and first recognized in the United States in 1962, many key advances have been made in our understanding of the diversity of the rickettsial organisms responsible for ehrlichiosis and anaplasmosis in dogs and, occasionally, cats, the vectors capable of transmitting these agents, and the role these organisms play as both important veterinary pathogens and zoonotic disease agents. Despite considerable progress in the field, much remains to be learned regarding mechanisms contributing to pathogenesis, effective treatment modalities, and prevention strategies that best protect pet health. This article highlights current understanding of the transmission, diagnosis, and management of ehrlichiosis and anaplasmosis in dogs and cats.

Haemotropic mycoplasmas: what's their real significance in cats?

Practical relevance

The feline haemotropic mycoplasmas (‘haemoplasmas') are a group of bacteria that can induce haemolytic anaemia in cats. Mycoplasma haemofelis is the most pathogenic of the species; ‘Candidatus Mycoplasma haemominutum’ and ‘Candidatus Mycoplasma turicensis’ are less pathogenic. The natural route of transmission of feline haemoplasma infection has not been confirmed, but fleas are implicated. When disease results, common clinical signs are pallor, lethargy, anorexia, weight loss, depression, dehydration and pyrexia. Treatment with tetracyclines or fluoroquinolones is usually effective at resolving clinical disease, but clearance of infection may not result.

Global importance

The feline haemoplasmas are found worldwide, although prevalence varies geographically.

Patient group

Older male non-pedigree cats are believed to be at increased risk of haemoplasma infection, although younger cats are possibly more likely to show clinical disease associated with M haemofelis.

Clinical challenges

The significance of feline haemoplasma infection is difficult to determine due to the existence of asymptomatic carrier cats and the variable pathogenicity of the haemoplasma species. Polymerase chain reaction (PCR) results should be interpreted in the light of the patient's clinical signs and haematological findings, infecting haemoplasma species and level of haemoplasma DNA present in the blood. Trial antibiotic treatment for haemoplasmosis may be warranted in suspected cases while awaiting PCR results.

Evidence base

Aspects of feline haemoplasmosis, particularly risk factors, pathogenesis, diagnostic methods and treatment, have been the focus of much recent research. This article draws on the current evidence base with a view to helping clinicians diagnose and manage cases more effectively.

Prevalence of selected infectious agents in cats in Ireland

Vector-borne bacterial and rickettsial agents and Toxoplasma gondii, are common organisms in cats. Some are potentially zoonotic or may be transmitted via blood transfusion. The current study investigated the prevalence of these agents in cats from Dublin, Ireland, for which no published data exists. Whole blood (n=116) and sera (n=83) samples were obtained from 121 cats. DNA was extracted from blood and assayed using polymerase chain reaction techniques for Anaplasma species, Bartonella species, Ehrlichia species, Mycoplasma haemofelis, 'Candidatus Mycoplasma haemominutum', 'Candidatus Mycoplasma turicensis' and Rickettsia species. IgG and T gondii IgG and IgM serum antibodies were detected by enzyme-linked immunosorbent assay. DNA consistent with B henselae (3.4%), B clarridgeiae (0.8%), both Bartonella species (0.8%), C M haemominutum (12.9%), or M haemofelis (2.5%) was amplified from 24/116 blood samples (20.6%). Antibodies to T gondii and Bartonella species were detected in 28 (33.7%) and 22 (26.5%) of 83 sera, respectively.

Pseudomonas fluorescens contamination of a feline packed red blood cell unit and studies of canine units

Background: While screening programs have reduced the risk of infectious disease transmission by donors in human and veterinary blood banking, bacterial contamination of blood products has emerged as a major complication in human medicine.

Objectives: To describe a Pseudomonas fluorescens (Pf)‐contaminated feline packed RBC (pRBC) unit and experimentally investigate Pf‐contaminated canine pRBCs.

Methods: Canine pRBCs were inoculated with Pf‐rich pRBCs from the sentinel feline unit and stored at 4°C or 20°C for 72 hours. Aliquots from the pRBCs were serially evaluated by microscopy, culture, and a eubacterial 16S rRNA real‐time PCR assay.

Results: One Pf‐contaminated feline unit turned black after 22 days of storage and was removed from the blood bank; a source was not found, and no other contaminated units were identified. Canine pRBCs spiked with 5 or 25 μL of the sentinel unit became culture‐ and/or 16S PCR‐positive at ≥8 hours at 20°C and 48 hours at 4°C and developed a color change at ≥24 hours. Sensitivity studies indicated that without incubation, inoculation of ≥100 μL Pf‐rich pRBCs was necessary for a positive 16S PCR test result.

Conclusions: P. fluorescens grows in stored pRBCs slowly at 4°C and rapidly at 20°C. Screening of blood products for color change, estimating bacterial concentration with microscopy, and 16S PCR testing are simple and fast ways to detect bacteria in stored blood. Aseptic collection, temperature‐controlled storage, and regular visual monitoring of stored units is recommended. Discolored units should not be transfused, but examined for bacterial contamination or other blood product quality problems.

Meta-analysis of coinfection and coexposure with Borrelia burgdorferi and Anaplasma phagocytophilum in humans, domestic animals, wildlife, and Ixodes ricinus-complex ticks

Anaplasma phagocytophilum, which causes granulocytic anaplasmosis, and Borrelia burgdorferi, the agent of Lyme borreliosis, are transmitted in multiple Holarctic regions by the same Ixodes sp. tick vectors and maintained in sylvatic cycles with the same rodent reservoirs. Coinfection of humans, domestic animals, wildlife, and ticks with both B. burgdorferi and A. phagocytophilum appears to be common, yet the pathologic mechanisms and ecology remain poorly understood compared with single-agent infection. We compiled available literature describing experimental and naturally occurring coinfection with B. burgdorferi and A. phagocytophilum in I. ricinus-complex ticks and host species, including wildlife, humans, livestock, and pets; calculated odds ratios for coinfection risks; evaluated the hypotheses that odds ratios for coinfection differ significantly between different tick life stages, ticks and vertebrate hosts, and reservoir and nonreservoir hosts; and finally, calculated the predicted coinfection prevalence based on the probability of each pathogen alone and compared this to the reported coinfection prevalence. Sixty-one manuscripts referenced coinfection or coexposure between these pathogens, with prevalence estimates for coinfection up to 67% in vertebrates and 28% in ticks. Of 61 different reports of coinfection or coexposure, 18 had odds ratios for coinfection significantly higher than 1. The combined odds ratios for coinfection in vertebrates and ticks were 1.9 and 1.28, respectively, with statistically significant variability among host and tick species in odds ratios. The overall predicted coexposure prevalence for vertebrates was 3.1% compared with an observed 8.9% prevalence. Odds ratios were not significantly different among classes of vertebrate hosts, species of ticks, stages of ticks, or ticks compared with hosts. We confirm a considerable level of coinfection and coexposure with these pathogens, although not predictably across host or tick species or geographical region.

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.

Prevalence of Anaplasma phagocytophilum in domestic felines in the United States

Anaplasma phagocytophilum is among the more common tick-borne disease agents in the United States. It is of veterinary and public health significance as dogs, cats, and human beings are known to be susceptible. A. phagocytophilum is transmitted trans-stadially by either nymphs or adults of either the black-legged tick (Ixodes scapularis) or the western black-legged tick (Ixodes pacificus). Little information is available regarding either the prevalence of this agent in cats or the dynamics of vector transmission. Four hundred and sixty feline blood samples from sites throughout the United States were assayed for antibodies to A. phagocytophilum using an indirect immunofluorescence assay (IFA). Results of the prevalence study showed that 20 samples (4.3%) were positive for A. phagocytophilum antibodies by IFA at a 1:50 dilution, however these results could not be confirmed by PCR analysis. PCR analysis for other cross-reacting Ehrlichia/Anaplasma spp. was also negative. These results demonstrate that natural infection of A. phagocytophilum in cats is uncommon.

Bartonella henselae infection in splenectomized domestic cats previously infected with hemotropic Mycoplasma species

Cat scratch disease is caused by Bartonella henselae and the domestic cat represents its main reservoir. In immunocompromised patients, infection with B. henselae is characterized by more severe clinical forms than in non-immunocompromised individuals. The objective of the present study was to investigate the characteristics of B. henselae (Houston-I strain) infection in four splenectomized and three non-splenectomized cats, five of which were chronically infected with 'Candidatus Mycoplasma haemominutum'. No major clinical signs were observed in either group of cats. Cats in both splenectomized and non-splenectomized groups became bacteremic within a week post-inoculation. Although bacteremia was on average 10 days longer in the splenectomized cats, that difference was not statistically significant (P=0.72). In both groups, the level of bacteremia peaked within the same time frame; however, the level of bacteremia was about 10-fold higher in the splenectomized cats (P=0.007). Such a difference could be associated with a reduced immune response to the infection, especially a reduced ability to phagocytize Bartonella organisms in the splenectomized cats. Concurrent infection with 'Candidatus M. haemominutum' did not appear to alter the course of infection.

Canine and feline blood donor screening for infectious disease

Consensus Statements of the American College of Veterinary Internal Medicine (ACVIM) provide veterinarians with guidelines regarding the pathophysiology, diagnosis, or treatment of animal diseases. The foundation of the Consensus Statement is evidence‐based medicine, but if such evidence is conflicting or lacking, the panel provides interpretive recommendations on the basis of their collective expertise. The Consensus Statement is intended to be a guide for veterinarians, but it is not a statement of standard of care or a substitute for clinical judgment. Topics of statements and panel members to draft the statements are selected by the Board of Regents with input from the general membership. A draft prepared and input from Diplomates is solicited at the Forum and via the ACVIM Web site and incorporated in a final version. This Consensus Statement was approved by the Board of Regents of the ACVIM before publication.