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Feline coronavirus (FCoV) infection initiates monocyte-associated viremia and viral persistence. Virus-infected, -activated monocytes also trigger feline infectious peritonitis (FIP), a fatal systemic disease of felids typified by granulomatous (peri)phlebitis. Currently, the exact mechanisms inducing monocyte activation and FIP are unknown. This study attempted to identify the potential immediate effect of virulent FCoV on colony-stimulating factor (CSF) (granulocyte (G)-CSF, monocyte (M)-CSF and granulocyte-monocyte (GM)-CSF levels through in vitro assessment, alongside prototypical pro- and anti-inflammatory mediators (interleukin (IL)-1, IL-6, IL-12p40, tumor necrosis factor (TNF)-α, and IL-10); this was assessed alongside the in vivo situation in the hemolymphatic tissues of cats euthanized with natural end-stage FIP. For the in vitro work, isolated monocytes from SPF cats were cultured short-term and infected with the FIP virus (FIPV) strain DF2. Mediator transcription was assessed by quantitative reverse transcriptase PCR (RT-qPCR) at 3, 6 and 9 h post infection (hpi), and in the post-mortem samples of bone marrow, spleen, and mesenteric lymph nodes (MLN) of cats with FIP. We observed limited and transient changes in cytokine transcription in monocytes after infection, i.e., a significant increase of IL-6 at 3 hpi and of GM-CSF over the 3 and 6 hpi period, whereas M-CSF was significantly decreased at 9 hpi, with a limited effect of age. The findings indicate that the infection induces expansion of the monocyte/macrophage population, which would ensure the sufficient supply of cells for consistent viral replication. In natural disease, the only upregulation was of G-CSF in the MLN, suggesting either immune exhaustion or an active downregulation by the host as part of its viral response.

Background: Feline coronavirus (FCoV) infection in cats is common, usually only causing mild intestinal signs, such as diarrhoea. It is highly infectious and found worldwide. A sequela of FCoV infection, feline infectious peritonitis (FIP), is a common cause of death in young cats, occurring in up to 10 per cent of cats infected with FCoV. Although suspicion of FIP is frequent in sick, particularly young, cats, obtaining a definitive diagnosis using non- or minimally-invasive approaches is difficult. Aim of the article: This article provides an update regarding diagnosing cases of FIP and guidance on current treatment recommendations.

Case summary A 7-month-old Siberian cat was presented for investigation of acute onset multifocal neurological deficits. Neurological examination documented dull mental status and an ambulatory left hemiparesis. Serum biochemistry documented marked hyperglobulinaemia. MRI of the brain identified marked leptomeningeal contrast enhancement extending along the brainstem caudally to involve the cranial cervical spinal cord. MRI of the cervical spine further identified a subarachnoid diverticulum that extended from the level of the obex to the C2–C3 vertebrae. Cerebrospinal fluid quantitative RT-PCR was positive for the presence of feline coronavirus. Histopathology revealed pyogranulomatous meningitis and choroid plexitis, uveitis and nephritis. Relevance and novel information This article describes the first reported case of a subarachnoid diverticulum associated with feline infectious peritonitis.

Feline infectious peritonitis (FIP) is a coronavirus-induced disease of cats, in which the immune system is known to play a crucial, but complex, role in the pathogenesis. This role is still incompletely understood, with involvement of both host and viral factors. To evaluate differential gene expression and pathway involvement in feline coronavirus (FCoV) infection and FIP, we applied next-generation RNA-sequencing of the mesenteric lymph nodes from cats with naturally-acquired FIP, as well as those with systemic FCoV infection without FIP, and those with neither. Viral infection was associated with upregulation of viral defenses regardless of the disease state, but to a greater degree in FIP. FIP was associated with higher pro-inflammatory pathway enrichment, whilst non-FIP FCoV-positive cats showed lower enrichment of humoral immunity pathways, below that of uninfected cats in the case of immunoglobulin production pathways. This host response is presumed to be protective. In FIP, downregulation of T cell-related processes was observed, which did not occur in non-FIP FCoV-positive cats. These results emphasize the importance of the host&rsquo, s immune balance in determining the outcome of the FCoV infection.

Objectives Feline infectious peritonitis (FIP) is a high mortality infectious disease. Single nucleotide polymorphisms (SNPs) in the genes encoding interferon gamma ( IFNG), tumour necrosis factor alpha ( TNFA) and dendritic cell-specific intercellular adhesion molecule-grabbing non-integrin (DC-SIGN; CD209) have been associated with increased and decreased risk of developing FIP. This study was designed to determine whether these associations were present in a UK population of pedigree cats using samples from cats euthanased with a confirmed diagnosis (FIP, n = 22; non-FIP, n = 10) or clinically healthy cats over 11 years of age (n = 3). Methods DNA was extracted from tissue (n = 32) or blood (n = 3) and PCR performed for regions of IFNG, TNFA and CD209. PCR amplicons were sequenced, each SNP genotype was determined, and genotype/allele frequency for each SNP and FIP status were compared. Results No significant association was found between the genotype and FIP status for any SNP analysed. There was a trend for the heterozygous CT genotype at both IFNG g.401 and IFNG g.408 to be associated with FIP ( P = 0.13), but this genotype was also found in a substantial proportion of non-FIP cats. There was also a trend for the heterozygous CT genotype at IFNG g.428 to be associated with FIP ( P = 0.06), although most cats with FIP had the CC genotype at this locus. No associations were found between any allele at TNFA g.-421, CD209 g.1900, CD209 g.2276, CD209 g.2392 and CD209 g.2713 and FIP. Conclusions and relevance The use of the IFNG, TNFA and CD209 SNPs described to predict the risk of FIP cannot currently be recommended.

“The wall-less, hemotropic, mycoplasma species Mycoplasma haemofelis, “Candidatus Mycoplasma turicensis” and, to a lesser extent, “Candidatus Mycoplasma haemominutum” have the potential to induce clinical hemolytic anemia in infected cats. Prevalence varies markedly between infecting species, complicated by a chronic carrier state. Accurate and prompt confirmation of infection and identification of the infecting hemoplasma species enables appropriate antibiotics (eg, tetracycline; fluoroquinolone) to be prescribed. Although cats with hemoplasmosis respond rapidly to antibiosis and supportive care, initial monotherapy treatment rarely results in clearance of infection. A protocol now exists for the clearance of the most pathogenic feline hemoplasma M haemofelis.”

Case summary A 3.5-year-old domestic shorthair cat presented with a 6 month history of weight loss and polyphagia. Clinical examination revealed a markedly reduced body condition score (2/9) and a quiet demeanour. Laboratory abnormalities comprised a mild non-regenerative anaemia, stress leukogram, hypoproteinaemia due to hypoalbuminaemia, azotaemia, hypokalaemia, total hypocalcaemia and sub-maximally concentrated urine (specific gravity 1.020). Abdominal ultrasonography revealed marked thickening of the gastric mucosa within the fundus, body and pylorus; the most dorsal portion of the fundus was spared. The thickened mucosa contained multiple small, anechoic cyst-like structures. The gastric submucosa, muscularis and serosa appeared normal. Histopathology, performed on a full-thickness gastric biopsy, revealed mucosal hypertrophy and markedly dilated gastric glands in areas; not all gastric glands were affected, with some appearing normal or atrophic. Focal interstitial fibrosis was present in some areas. The findings of hypoproteinaemia, gastric ultrasonographic changes and histopathology results share several similarities to those reported with Ménétrier disease. Relevance and novel information Ménétrier disease is a rare condition of the stomach in humans. A similar condition, giant hypertrophic gastritis (or Ménétrier-like disease), has also been described rarely in dogs. To our knowledge, Ménétrier-like disease has not been previously described cats. This case shares features of Ménétrier-like disease, raising the suspicion of a similar aetiopathogenesis.

Summary Feline infectious peritonitis (FIP) is an almost invariably fatal feline coronavirus (FCoV)-induced disease thought to arise from a combination of viral mutations and an overexuberant immune response. Natural initial enteric FCoV infection may remain subclinical, or result in mild enteric signs or the development of FIP; cats may also carry the virus systemically with no adverse effect. This study screened mesenteric lymph nodes (MLNs), the presumed first site of FCoV spread from the intestine regardless of viraemia, for changes in the transcription of a panel of innate immune response mediators in response to systemic FCoV infection and with FIP, aiming to identify key pathways triggered by FCoV. Cats with and without FIP, the latter with and without FCoV infection in the MLN, were compared. Higher expression levels in FIP were found for toll-like receptors (TLRs) 2, 4 and 8. These are part of the first line of defence and suggest a response to both viral structural proteins and viral nucleic acid. Expression of genes encoding inflammatory cytokines and chemokines, including interleukin (IL)-1β, IL-6, IL-15, tumour necrosis factor (TNF)-α, CXCL10, CCL8, interferon (IFN)-α, IFN-β and IFN-γ, was higher in cats with FIP, consistent with inflammatory pathway activation. Expression of genes encoding transcription factors STAT1 and 2, regulating signalling pathways, particularly of the interferons, was also higher. Among cats without FIP, there were few differences between virus-positive and virus-negative MLNs; however, TLR9 and STAT2 expression were higher with infection, suggesting a direct viral effect. The study provides evidence for TLR involvement in the response to FCoV. This could open up new avenues for therapeutic approaches.

Feline infectious peritonitis (FIP) is a common infectious cause of death in cats, with heritable host factors associated with altered risk of disease. To assess the role of feline interferon-gamma gene (fIFNG) variants in this risk, the allele frequencies of two single nucleotide polymorphisms (SNPs) (g.401 and g.408) were determined for non-pedigree cats either with confirmed FIP (n = 59) or from the general population (cats enrolled in a large lifetime longitudinal study, n = 264). DNA was extracted from buccal swabs or tissue samples. A pyrosequencing assay to characterize the fIFNG SNPs was designed, optimized and subsequently performed on all samples. Genotype and allele frequency were calculated for each population. Characterization of the target SNPs was possible for 56 of the cats with FIP and 263 of the cats from the general population. The SNPs were in complete linkage disequilibrium with each other. There was an association between FIP status and genotype (&chi, 2, p = 0.028), with a reduced risk of developing FIP (&chi, p = 0.0077) associated with the genotype TT at both positions. These results indicate that, although fIFNG variants may be associated with altered risk of disease, the prevalence of individual variants within both populations limits application of their characterization to breeding purposes.

Background Feline coronavirus (FCoV) infection is common. In a small percentage of cats, FCoV infection is associated with the fatal disease feline infectious peritonitis (FIP). Genetically distinct virulent and avirulent strains of FCoV might coexist within a cat population. Objectives To determine whether the strains of FCoV in FIP-affected cats are closely related or genetically distinct from the fecally derived strains of FCoV in contemporary-asymptomatic cats during an epizootic outbreak of FIP. Animals Four cats euthanized because of FIP and 16 asymptomatic cats. Methods This prospective outbreak investigation was initiated during an outbreak of FIP in cats within or rehomed from a rescue/rehoming center. Postmortem samples were collected from cats with FIP and contemporaneous fecal samples from asymptomatic cats. RNA was purified from tissue and fecal samples, FCoV gene fragments were reverse transcribed, PCR-amplified using novel primers, and sequenced. Sequences were aligned with ClustalW and compared with published FCoV sequences. Results FCoV RNA was detected in all 4 FIP cat postmortem samples and in 9 of the 16 fecal samples from contemporary-asymptomatic cats. Novel primers successfully amplified fragments from 4 regions of the genome for all FCoV-positive samples. Phylogenetic analysis showed that the FIP-associated strains of FCoV from the outbreak were very closely related to the fecally derived strains of FCoV from contemporary-asymptomatic cats. Conclusions and Clinical Importance Sequence analysis provided no evidence that genetically distinct virulent and avirulent strains of FCoV were present during this FIP outbreak.

Background Neurodegenerative diseases are a heterogeneous group of disorders characterized by loss of neurons and are commonly associated with a genetic mutation. Hypothesis/Objectives To characterize the clinical and histopathological features of a novel degenerative neurological disease affecting the brain of young adult Nova Scotia Duck Tolling Retrievers (NSDTRs). Animals Nine, young adult, related NSDTRs were evaluated for neurological dysfunction and rapid eye movement sleep behavior disorder. Methods Case series review. Results Clinical signs of neurological dysfunction began between 2 months and 5 years of age and were progressive in nature. They were characterized by episodes of marked movements during sleep, increased anxiety, noise phobia, and gait abnormalities. Magnetic resonance imaging documented symmetrical, progressively increasing, T2-weighted image intensity, predominantly within the caudate nuclei, consistent with necrosis secondary to gray matter degeneration. Abnormalities were not detected on clinicopathological analysis of blood and cerebrospinal fluid, infectious disease screening or urine metabolite screening in most cases. Postmortem examination of brain tissue identified symmetrical malacia of the caudate nuclei and axonal dystrophy within the brainstem and spinal cord. Genealogical analysis supports an autosomal recessive mode of inheritance. Conclusions and Clinical Importance A degenerative encephalopathy was identified in young adult NSDTRs consistent with a hereditary disease. The prognosis is guarded due to the progressive nature of the disease, which is minimally responsive to empirical treatment.

Objectives: The aims of this study were to determine the prevalence of canine haemoplasmas, Mycoplasma haemocanis and “Candidatus Mycoplasma haematoparvum” infection in Central Macedonia, Greece, and to evaluate any associations between canine haemoplasma infection and clinical presentation, selected laboratory data or the presence of ticks. Methods: Genomic DNA was purified from excess blood (n=151) submitted for haematological examination. Purified DNA was subjected to species-specific quantitative polymerase chain reaction assays duplexed with a canine DNA control quantitative polymerase chain reaction. Clinical records were retrospectively examined and selected clinical parameters were compared to haemoplasma infection status. Results: Nine samples were excluded due to inadequate canine DNA polymerase chain reaction results. Of the remaining 142 samples: eight (5·6%) were positive for M. haemocanis alone, six (4·2%) were positive for “Ca. M. haematoparvum” alone and one (0·7%) was dual positive. No association was found between haemoplasma status and age, sex, breed, health status, presence of anaemia, selected biochemistry parameters, presence of ectoparasites, routine ectoparasiticide treatment or the presence of selected tick-borne diseases.

Objective: The aim of this study was to investigate whether the two canine haemoplasma species, Mycoplasma haemocanis and “Candidatus Mycoplasma haematoparvum,” are commonly associated with immune-mediated haemolytic anaemia (IMHA) in UK dogs. Methods: Three groups of dogs were recruited to the study: anaemic dogs with primary IMHA (n=37); anaemic dogs not meeting the inclusion criteria for primary IMHA (n=77) and non-anaemic dogs (n=113). DNA was extracted from 100 μl of blood and subjected to real-time quantitative polymerase chain reaction (qPCR) assays for both species of Mycoplasma. Each assay incorporated co-amplification of canine glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as an endogenous internal control. Results: Canine GAPDH was successfully amplified by qPCR from all 227 canine blood samples but none contained M. haemocanis or “Candidatus M. haematoparvum” DNA. Clinical Significance: Haemoplasma infection is uncommon in dogs in the UK and no evidence was found that these organisms act as triggers for IMHA.

Two canine haemoplasma species have been recognised to date; Mycoplasma haemocanis (Mhc), which has been associated with anaemia in splenectomised or immunocompromised dogs, and “Candidatus Mycoplasma haematoparvum” (CMhp), recently described in an anaemic splenectomised dog undergoing chemotherapy. The study aim was to develop quantitative real-time PCR assays (qPCRs) incorporating an endogenous internal control to detect Mhc and CMhp and to apply these assays to DNA samples extracted from canine blood collected in Northern Tanzania (n = 100) and from dogs presented to a Trinidadian veterinary hospital (n = 185). QPCRs specific for Mhc and CMhp were designed using 16S rRNA gene sequence data, and each was duplexed with an assay specific for canine glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The assays detected ≤10 copies of a sequence-specific haemoplasma plasmid per reaction and neither assay showed cross-reactivity with 106 copies of the sequence-specific plasmid from the non-target canine haemoplasma species. Nineteen of the 100 Tanzanian samples (19%) were positive for Mhc alone and one (1%) was dually infected. One Trinidadian sample was negative for canine GAPDH DNA and was excluded from the study. Of the 184 remaining Trinidadian samples, nine (4.9%) were positive for Mhc alone, five (2.7%) for CMhp alone, and two (1.1%) dually infected. This is the first report of canine haemoplasma qPCR assays that use an internal control to confirm the presence of amplifiable sample DNA, and their application to prevalence studies. Mhc was the most commonly detected canine haemoplasma species.

OBJECTIVES The aim of this study was to determine the agreement between AB blood phenotyping and genotyping and determine whether non-AB blood type incompatibilities exist in UK cats. METHODS Blood samples underwent phenotyping (A, B or AB) using microplate agglutination, and genotyping (AA, Ab or bb) using pyrosequencing of a fragment of the cytidine monophospho-N-acetylneuraminic acid hydroxylase gene. Non-AB blood type incompatibilities were investigated by cross-matching against reference blood of the same phenotype. RESULTS Of 112 cats tested, 86 (77%) were blood phenotype A, 19 (17%) type B and 7 (6%) type AB. Genotype and initial phenotype agreed in 96% (107 of 112) of cats, but 5 were discordant; these were all B phenotype with either AA (n=2) or Ab (n=3) genotype. Two of the five cats had repeat blood samples tested: one was reclassified as phenotype A; the other remained phenotype B. Two cats had incompatibilities on minor cross-match, but these were attributed to phenotyping errors. CLINICAL SIGNIFICANCE Unknown mutation(s) associated with phenotype B, resulting in false AA or Ab genotyping, were evident in a small number of cases in this study. No conclusive evidence for non-AB blood type incompatibilities was found.

Background Tick-borne haemoparasites Babesia vogeli and Anaplasma platys are common among the free-roaming canine populations associated with Aboriginal communities in Australia, whilst the prevalence of haemoplasmas, which are also suspected to be tick-borne, remained unexplored. The aim of this study was to determine the prevalence of haemoplasma infection in these populations, and to identify any correlation with other haemoparasites. Blood was collected from 39 dogs associated with four Aboriginal communities and screened for infection using PCR and serology. DNA was purified and PCR analyses for piroplasms, Anaplasmataceae family bacteria and haemoplasmas performed. Serum was analysed using a commercial haemoparasite ELISA. Prevalence of infection was compared between communities. Results Seventeen dogs (44%) were infected (PCR positive) with Mycoplasma haemocanis, eight (21%) with ‘Candidatus Mycoplasma haematoparvum’, 20 (51%) with A. platys, and 17 (44%) with B. vogeli. Two dogs were infected with a novel haemoplasma as determined by DNA amplification and sequencing. Two dogs (5%) were serologically positive for Dirofilaria immitis antigens, one (3%) was positive for Ehrlichia canis antibodies and nine (24nbsp;%) were positive for A. platys antibodies. Co-infections were frequent. Haemoplasma prevalence was highest (73%, 16/22) in Central Australia and lowest (22%, 2/9) in Western Australia (p = 0.017). In contrast, B. vogeli prevalence was low in Central Australia (18%, 4/22) but higher (78%, 7/9) in Western Australia (p = 0.003). Conclusions This is the first time haemoplasma infections, including a novel species, have been molecularly documented in Australian dogs. The wide regional variation in prevalence of some of the haemoparasite infections detected in this study warrants further investigation.