Infection with a proposed new subspecies of Babesia canis, Babesia canis subsp. presentii, in domestic cats

Parasitemia with a large Babesia species was identified in two domestic cats from Israel. One cat, also coinfected with feline immunodeficiency virus and "Candidatus Mycoplasma haemominutum," had profound icterus and anemia which resolved after therapy, whereas a second cat was an asymptomatic carrier. Amplification and sequencing of the 18S rRNA gene, followed by phylogenetic analyses, indicated that infection was caused by Babesia canis. However, the sequences of the internal transcribed and 5.8S rRNA regions of the ribosomal operon used for subspeciation of B. canis were markedly different from the recognized subspecies of B. canis, which include B. canis vogeli, B. canis canis, and B. canis rossi. Based on phylogenetic comparisons of the 18S rRNA gene, 5.8S, and internal transcribed spacer sequences of the isolates from the cats and on the smaller sizes of the merozoite and trophozoite stages of this parasite, which distinguish it from the subspecies of B. canis present in dogs, we propose to identify the novel feline genotype of B. canis described in the present study as a new subspecies, B. canis subsp. presentii.

Phylogenetic analysis of hemoplasma species: an international study

Nearly complete 16S rRNA gene sequences for feline and canine hemoplasma isolates from Europe, Australia, Africa, and Asia showed almost 100% identity to those previously reported for United States isolates. Partial sequences of the RNA subunit of the RNase P gene were also determined, and RNase P-based phylogenetic analysis showed that the hemoplasmas are most closely related to the members of the Mycoplasma pneumoniae group.

Use of a PCR assay to assess the prevalence and risk factors for Mycoplasma haemofelis and 'Candidatus Mycoplasma haemominutum' in cats in the United Kingdom

Blood samples from 426 healthy and sick cats in the UK were tested in a PCR assay for 'Candidatus Mycoplasma haemominutum' and Mycoplasma haemofelis (basonym Haemobartonella felis). Seventy-two of the cats (16.9 per cent) were positive for 'Candidatus M. haemominutum' alone, six (1.4 per cent) were positive for M. haemofelis alone and one (0.2 per cent) was positive for both. Logistic regression analysis indicated that older male cats were significantly more likely to be infected with 'Candidatus M. haemominutum', but there was no significant association between it and any of the haematological variables measured. M. haemofelis infection was uncommon in the anaemic cats sampled, and there were too few positive cases for multivariable analysis to be performed for M. haemofelis-positive status.

Use of real-time PCR to detect and quantify Mycoplasma haemofelis and "Candidatus Mycoplasma haemominutum" DNA

A real-time PCR assay using Taqman probes was developed to detect and quantify Mycoplasma haemofelis and "Candidatus Mycoplasma haemominutum" in feline blood samples. The assay was rapid and sensitive and was successfully used to monitor the in vivo kinetics of cats experimentally infected with each species.

Melting curve analysis of feline calicivirus isolates detected by real-time reverse transcription PCR

A real-time reverse transcription polymerase chain reaction assay was developed to detect feline calicivirus infection in cats. Using SYBR green I melting curve analysis, isolates could be distinguished by their melting temperature. The assay is sensitive, linear over a wide range of template concentrations and allows accurate quantitation of viral load.

Haemobartonella felis: recent developments in diagnosis and treatment

Haemobartonella felis is a pleomorphic uncultivated wall-less haemotrophic bacterial parasite. Phylogenetic analysis of 16S rRNA gene sequences from a number of isolates of H felis has demonstrated that these bacteria are most closely related to species in the genus Mycoplasma, and Haemobartonella and related organisms are currently being reclassified as Mollicutes. Diagnosis by cytological examination of blood smears has been problematic, but recent molecular studies have led to the development of sensitive polymerase chain reaction (PCR) assays for diagnosis. Such studies have also resulted in the recognition of two distinct strains of H felis, which are divided into different groups based on phylogenetic analysis. This evolutionary divergence between strains is accompanied by differences in pathogenecity. This review discusses new developments in the diagnosis and treatment of H felis, focusing on the use of, and interpretation of, PCR assays.

16S rDNA comparison demonstrates near identity between an United Kingdom Haemobartonella felis strain and the American California strain

A handful of North American (USA) strains of the uncultured erythrocytotrophic pathogen of cats, Haemobartonella felis, have been differentiated by comparison of the 16S rRNA gene sequences. Using this approach, an UK strain was characterised, providing an identity for a non-USA H. felis for the first time. This strain shared close phylogenetic homology with the USA Californian strain.

Evaluation of methods of platelet counting in the cat

Platelet counts were performed in 50 cats presented for diagnostic investigation. For each cat, counts were obtained using a manual haemocytometer method and compared with counts obtained by estimation from a stained blood smear, a QBC VetAutoread analyser, a Zynocyte VS/2000 analyser, impedance automated counts on a Baker System using both EDTA and citrated anticoagulated blood, and use of a Zynostain modified counting chamber kit. None of the methods gave high correlation with the haemocytometer counts. The blood smear estimation of platelet counts had the highest correlation (r = 0.776) and was the only method to have reasonable values for both sensitivity and specificity. With the impedance automated counts, citrated anticoagulated blood had marginally higher correlation than EDTA anticoagulated blood, and the time between blood sampling and platelet count determination had no effect on the count obtained. When in-house analyser or impedance automated platelet counts are abnormal or not consistent with clinical findings, the authors recommend that a manual platelet count using either haemocytometry or examination of a blood smear is performed.

Use of real-time quantitative PCR to detect Chlamydophila felis infection

A real-time PCR assay was developed to detect and quantify Chlamydophila felis infection of cats. The assay uses a molecular beacon to specifically identify the major outer membrane protein gene, is highly reproducible, and is able to detect fewer than 10 genomic copies.

Hypoadrenocorticism in a cat

Primary hypoadrenocorticism was diagnosed in an eight-year-old neutered male cat. The predominant presenting complaint was dysphagia. Other historical signs included lethargy, weight loss, polydipsia, polyuria, muscle weakness and occasional vomiting. The signs had waxed and waned over the two months before presentation and had improved when the cat was treated with enrofloxacin and prednisolone by the referring veterinarian. On referral, dehydration, depression and poor bodily condition were found on physical examination. Results of initial laboratory tests revealed mild anaemia, hyperkalaemia, hyponatraemia, hypochloraemia and elevations in serum creatinine and creatine kinase. The diagnosis of primary adrenocortical insufficiency was established on the basis of results of an adrenocorticotropic hormone (ACTH) stimulation test and endogenous plasma ACTH determination. Initial therapy for hypoadrenocorticism included intravenous administration of 0.9 per cent saline and dexamethasone, and oral fludrocortisone acetate. Within one week the cat was clinically normal and two years later was still alive and well on fludrocortisone acetate treatment only.

Spontaneous laryngeal paralysis in four white-coated German shepherd dogs

Four cases of spontaneous laryngeal paralysis in juvenile white-coated German shepherd dogs are described. The presenting signs were typical for laryngeal paralysis, with stridor present in all four cases. Laryngoscopy revealed bilateral laryngeal paralysis in three cases, and unilateral paralysis in one. Concurrent megaoesophagus was also identified in one dog. All dogs underwent surgical treatment for laryngeal paralysis. Euthanasia was performed in one case due to intractable regurgitation and aspiration pneumonia. A possible association with white coat colour is discussed.

Preliminary clinical observations on the use of piroxicam in the management of rectal tubulopapillary polyps

Rectal tubulopapillary polyps were diagnosed in eight dogs following proctoscopy and mucosal pinch biopsy. Histological examination of the pinch biopsies revealed evidence of malignant transformation in three of the cases. The remaining cases were diagnosed as benign polyps. Inflammatory changes were observed in four cases. Seven dogs were treated with piroxicam suppositories and one with oral piroxicam. All dogs were re-examined after four to six weeks of piroxicam therapy and the extent of haematochezia, tenesmus and faecal mucus production was reduced in all cases. The owners of seven of the dogs considered the improvement in clinical signs to be good or excellent. Cases with and without evidence of inflammation responded equally well. This finding supports the hypothesis that piroxicam has an antineoplastic effect due to apoptosis and alteration in the cell cycle. Medical management with piroxicam may provide a non-invasive treatment option for dogs with rectal polyp formation in which surgical treatment is likely to be associated with complications such as incontinence, infection and wound breakdown, or where the owner declines such treatment.

Idiopathic phenobarbital-responsive hypersialosis in the dog: an unusual form of limbic epilepsy?

Three unusual cases of salivary gland enlargement and hypersialosis in the dog that responded to anticonvulsant therapy are reported. Presenting complaints included weight loss, hypersalivation, retching and vomiting of several weeks' duration. Two dogs were presented with enlarged painful mandibular salivary glands. The third dog exhibited bizarre behaviour (including jaw chattering) and developed enlarged painful mandibular salivary glands during hospitalisation. Fine needle aspirate cytology and biopsies from the enlarged salivary glands revealed no significant pathological changes. In one dog, an electroencephalogram revealed changes consistent with epilepsy. Hypersialism and salivary gland enlargement resolved completely during phenobarbital administration in all cases. Two dogs were successfully weaned off treatment six months after diagnosis. The remaining dog relapsed after eight months, but normalised with the addition of oral potassium bromide. It is hypothesised that the syndrome idiopathic hypersialosis may in fact be an unusual form of limbic epilepsy.

Comparison of PCR detection methods for B1, P30, and 18S rDNA genes of T. gondii in aqueous humor

PURPOSE

Comparison of polymerase chain reaction (PCR) amplification of three Toxoplasma gondii genes in aqueous humor.

METHODS

Nested PCRs carried out using published methods were optimized for maximum sensitivity and specificity. Five pairs of oligonucleotide primers, directed against the B1, P30, and ribosomal genes, were used and compared to determine which sequences were most effective in detecting T. gondii DNA. Methods were developed with DNA templates in water and were subsequently applied to both normal and inflamed aqueous.

RESULTS

After one round of PCR amplification, P30 and ribosomal primers were able to detect 1 pg genomic T. gondii DNA. However, those directed against the B1 gene were able to detect 50 fg (approximately single tachyzoite). This level of sensitivity was also achieved using the P30 primers after a second round of PCR; however, only primers based on the B1 gene maintained this level of sensitivity in both normal and inflamed aqueous. B1-specific primers did not amplify sequences from fungal, bacterial, or human lymphocyte DNA. The sensitivity of T. gondii detection using B1 gene-specific primers was not compromised when large amounts of human lymphocyte DNA were present, and application to an ocular sample or retinal section from patients with toxoplasma chorioretinitis was successful in confirming the presence of T. gondii DNA.

CONCLUSIONS

The B1 PCR protocol appears to be the most sensitive protocol in the detection of T. gondii DNA and has been successful in identification of T. gondii DNA in ocular fluids and retinal sections. This provides direct evidence of the presence of T. gondii within the eye and may therefore help in the management of toxoplasma retinochoroiditis.

Use of a mucosal advancement flap for the treatment of nasopharyngeal stenosis in a cat

A three-and-a-half-year-old male neutered domestic short-haired cat was presented with a three-year history of stertor and intermittent open-mouth breathing. No airflow was detected from either nostril when checked using a cold slide test. Oropharyngeal swabs were positive for calicivirus, while skull radiographs were suggestive of a dorsal deviation of the soft palate. The diagnosis of nasopharyngeal stenosis was confirmed via cannulation of the nasal passages and direct examination of the oropharynx under general anaesthesia. A midline approach through the soft palate was used to excise the adhesions. The resulting defect was reconstructed by advancement of a mucosal flap elevated from the dorsal nasopharynx and laryngopharynx. The cat was free of clinical signs 28 months later.

Meningococcal pneumonia: characterization and review of cases seen over the past 25 years

Fifty-eight cases of meningococcal pneumonia were included in this review. Fifty cases previously described in the literature from 1974 through 1998 and 8 new cases were included in this series. The median age of patients was 57.5 years, and pleuritic chest pain was described in 21 (53.9%) of 39 cases. Blood cultures were positive in 42 (79.3%) of 53 cases for which results were mentioned. Despite the presence of bacteremia, patients did not develop the syndrome of meningococcemia with its associated complications. Serogroup Y meningococci were most commonly recovered and accounted for 44.2% of identified isolates. Therapy has dramatically changed over the past 25 years; prior to 1991, penicillin antibiotics were most often used. Since 1991, 12 (80%) of 15 patients received cephalosporin antibiotics. Only 5 (8.62%) of 58 patients died. Secondary cases of meningococcal infections following exposure to patients with meningococcal pneumonia were noted in 2 instances.

A case of feline primary hypoadrenocorticism

A 2-year-old entire female British Shorthair cat was referred to the University of Bristol for investigation of lethargy, weakness, constipation and hypothermia. Clinical examination revealed a profoundly weak, hypovolaemic and hypothermic cat. Serum biochemistry revealed hyponatraemia, hyperkalaemia and hyperphosphataemia and the urine was isosthenuric. Lack of response to exogenous adrenocorticotrophic hormone confirmed a diagnosis of hypoadrenocorticism. Treatment consisted initially of intravenous fluid therapy and subsequently a combination of fludrocortisone and prednisolone per os. At follow-up, 20 months after the initial diagnosis the cat remained stable and free of clinical signs.

Aetiology and diagnosis of persistent nasal disease in the dog: a retrospective study of 42 cases

Forty-two dogs with a history of persistent nasal disease were evaluated by a combination of clinical examination, thoracic and nasal radiography, retroflexed endoscopy and biopsy, and anterograde rhinoscopy and blind nasal biopsy. A definitive diagnosis was made in 91 per cent of cases. Neoplasia was the most common diagnosis (33 per cent of cases), followed by inflammatory rhinitis (24 per cent). Other diagnoses included periodontal disease (10 per cent), aspergillosis (7 per cent) and foreign bodies (7 per cent). Adenocarcinoma was the most common tumour diagnosed. The clinical findings were found to be too variable to be used as specific diagnostic criteria. Anterograde rhinoscopy and retroflexed endoscopy had higher specificity and sensitivity than radiology for the diagnosis of neoplasia, inflammatory rhinitis, aspergillosis and foreign bodies. With a systematic approach to the investigation of persistent nasal disease, a definitive diagnosis can be successfully obtained in the vast majority of cases.

Primary immune-mediated thrombocytopenia in a cat

A young female Somali cat was referred for investigation of chronic intermittent haematuria. Petechiae were found on the ears and ventral abdomen and further investigation revealed severe thrombocytopenia and megakaryocyte hyperplasia. Direct marrow immunohistochemistry detected anti-megakaryocyte autoantibody (Immunoglobulin G), but extensive investigation failed to find secondary causes of immune-mediated thrombocytopenia, so a diagnosis of primary (autoimmune) immune-mediated thrombocytopenia was concluded. Thrombocytopenia persisted despite aggressive immunosuppressive therapy (prednisolone, azathioprine and vincristine) but resolved after oral prednisolone was replaced with dexamethasone.

Obstructive inflammatory laryngeal disease in three cats

Three cats with upper respiratory tract obstruction due to laryngeal inflammation are presented. Cervical radiography showed the presence of a soft tissue mass in the laryngeal region in all cases, and laryngoscopy allowed direct visualization of a mass associated with the larynx. Laryngeal samples were obtained by a combination of fine needle aspiration, cutting biopsy forceps, by ventral laryngotomy, and at post-mortem. Histopathology of the laryngeal samples showed the presence of a predominantly granulomatous inflammation, with macrophage and lymphocyte infiltration. One case was euthanased due to severe dyspnoea. The remaining two cases underwent combined medical (corticosteroid and antibiotic) and surgical (permanent tracheostomy or excision of laryngeal tissue by ventral laryngotomy) treatment. One case died of an undetermined cause 15 weeks after surgery while the other case remains clinically well 20 months after diagnosis. Recognition of the existence of granulomatous laryngitis is important as clinical signs and radiographic findings are indistinguishable from laryngeal neoplasia.