Prevalence of Chlamydia psittaci in different cat populations in Britain

The prevalence of Chlamydia psittaci infection in household, feral and farm cats in Britain was investigated. Chlamydia were isolated from 30 per cent of conjunctival swabs collected from 753 household cats with conjunctivitis. The prevalence of active chlamydial infection was highest in cats in the age group five weeks to nine months. Males were more frequently infected than females. Cats with chlamydial conjunctivitis usually had antibody titres greater than 1024 as assessed by indirect immunofluorescence. Chlamydia appeared to be endemic in two out of three feral cat colonies on the basis of serological evidence and occasional isolations. Cats on 10 of 22 sheep farms (45 per cent) had serological evidence of chlamydial infection, and this was confirmed on two farms by isolation of the organism from conjunctival and, or, rectal swabs. This is the first survey of infection with Chlamydia psittaci in cat populations in Britain.     

Using CF0218-ELISA to distinguish Chlamydophila felis-infected cats from vaccinated and uninfected domestic cats

Chlamydophila felis is a causative agent of acute and chronic conjunctivitis and pneumonia in cats. Cats can be vaccinated with killed or attenuated C. felis. However, current serodiagnostics cannot distinguish these cats from naturally infected cats. This causes difficulty of early diagnosis and seroepidemiological survey for C. felis. We previously reported that C. felis CF0218 can be used as a C. felis-infection-specific diagnostic antigen in experimentally infected and/or vaccinated cats. In this study, we evaluated an enzyme-linked immunosorbent assay using recombinant CF0218 as antigen (CF0218-ELISA) to detect anti-C. felis antibody in 714 sera of domestic cats whose histories of vaccination against C. felis are known. The 44 vaccinated cats were 93% negative using CF0218-ELISA; half of these scored positive by immunofluorescence assay (IFA) using C. felis-infected cells as antigen. The 670 non-vaccinated cats had CF0218-ELISA positivity rates that were statistically in agreement with IFA (18% vs. 21%). These results show that CF0218, which was identified as a C. felis-infection-specific antigen, is a useful serodiagnostic antigen to distinguish naturally C. felis-infected cats from vaccinated and non-infected cats.     

Detection of Chlamydophila pneumoniae in cats with conjunctivitis

Objective To determine the presence of chlamydial species including recently described chlamydial agents as well as the human pathogen Chlamydophila pneumoniae in feline conjunctivitis. Animal studied Twenty five cats without and 49 cats with conjunctivitis were tested for chlamydia using a Chlamydiaceae real time (RT) PCR (targeting the 23S rRNA gene sequence), a Chlamydiales PCR (targeting the 16S rRNA gene sequence), and cell culture. The PCR products of all positive samples were sequenced and subsequently analyzed using a basic local alignment search tool search. Results Chlamydiaceae RT PCR and subsequent sequence analyses identified C. pneumoniae in five cats in the conjunctivitis group. The presence of Chlamydophila felis was shown in two cats with conjunctivitis. Chlamydiae related to uncultured members of Chlamydiales were detected in three conjunctivitis cases and in one cat without clinical symptoms. Conclusion This study detects for the first time, the known human pathogen C. pneumoniae in feline conjunctivitis cases using Chlamydiaceae RT PCR and sequence analyses.     

Chlamydia infection in cats in New Zealand

Conjunctival swabs collected in 1991-92 from 333 pedigree and non-pedigree cats were tested for the presence of Chlamydia spp. antigen using an ELISA antigen kit. Forty (18.4%) of the 217 samples from cats with conjunctivitis were positive. Seven (6%) of 116 samples from cats which were in contact with cats with conjunctivitis but which showed no clinical signs at the time of sample collection were positive. Positive-testing cats were frequently from multi-cat households. Chlamydia spp. is present and associated with conjunctivitis in cats in New Zealand. Infection may occur concurrently with viral diseases. Feline calicivirus was recovered from 27 (21 with conjunctivitis) of 37 cats tested in five catteries. Four cats (with conjunctivitis) were FIV-positive.     

Cytologic findings, and feline herpesvirus DNA and Chlamydophila felis antigen detection rates in normal cats and cats with conjunctival and corneal lesions

Samples were collected from 36 cats with feline herpesvirus (FHV-1)-related ocular disease (conjunctivitis, epithelial or stromal keratitis, or corneal sequestration), and 17 cats without ocular changes. Corneoconjunctival swabs, scrapings and biopsies were tested in various combinations for presence of FHV-1 DNA using single round (sr) polymerase chain reaction (PCR) and nested PCR (nPCR). Additional swabs from the inferior conjunctival fornix were tested by enzyme-linked immunosorbent assay for Chlamydophila felis antigen. Cytologic evaluation was carried out on conjunctival (cats with conjunctivitis) and corneal (cats with keratitis) cytobrush preparations. FHV-1 DNA was detected by PCR in 14 (39%) cats with ocular disease and 1 (6%) of the control group. Agreement between srPCR and nPCR results was significant (P < 0.01). FHV-1 DNA was detected in 3/7 cats with conjunctivitis, 5/6 cats with epithelial keratitis, 3/11 cats with stromal keratitis, and 3/12 cats with corneal sequestration. There was a significant association (P = 0.0027) between viral presence and epithelial keratitis. However, no significant association was found between viral presence and conjunctivitis (P = 0.059), stromal keratitis (P = 0.15), or corneal sequestration (P = 0.18). With respect to FHV-1 DNA detection, intersample agreement was significant (P < 0.03). No sampling technique seemed more likely than another to harvest detectable viral DNA, except for cats with corneal sequestrum in which viral DNA was not detected using corneoconjunctival swabs. FHV-1 DNA was detected in 6/9 samples with intranuclear inclusion bodies and in 6/7 cats with eosinophils on cytologic examination. All samples tested negative for C. felis antigen.     

Feline infectious pneumonia: a short literature review and a retrospective immunohistological study on the involvement of Chlamydia spp. and distemper virus

A short literature review of feline infectious pneumonia, feline Chlamydia and Paramyxoviridae is presented. In a retrospective study (from 1987 to 1996) 245 cases of feline pneumonia or conjunctivitis/rhinitis were investigated: histological diagnoses and aetiologies were compared; all lungs were examined immunohistologically for the occurrence of chlamydia and of canine distemper virus (CDV), but neither pathogen could be demonstrated. The results confirm previous reports indicating that feline chlamydia is not a primarily pulmonary pathogen and that CDV is not a causative agent of pneumonia in cats as it is in large felids.The review provides a summary of the known causes and pathology of infectious pneumonia in cats (in order of frequency), although some remain aetiologically uncertain. It focuses on chlamydia and distemper virus - a recognized and as yet unknown cause of feline pneumonia. The role and especially the frequency of chlamydia as a cause of feline pneumonia are controversial but distemper virus, known to cause pneumonia in dogs and large felids, has not as yet been demonstrated in cats. The aims of the retrospective study were to determine the occurrence of chlamydia in 245 cases of feline pneumonia or conjunctivitis/rhinitis, and to investigate the presence of CDV in these lungs.     

Chlamydia infection in cats in New Zealand

Conjunctival swabs collected in 1991-92 from 333 pedigree and non-pedigree cats were tested for the presence of Chlamydia spp. antigen using an ELISA antigen kit. Forty (18.4%) of the 217 samples from cats with conjunctivitis were positive. Seven (6%) of 116 samples from cats which were in contact with cats with conjunctivitis but which showed no clinical signs at the time of sample collection were positive. Positive-testing cats were frequently from multi-cat households. Chlamydia spp. is present and associated with conjunctivitis in cats in New Zealand. Infection may occur concurrently with viral diseases. Feline calicivirus was recovered from 27 (21 with conjunctivitis) of 37 cats tested in five catteries. Four cats (with conjunctivitis) were FIV-positive.     

A single dilution enzyme-linked immunosorbent assay for the quantitative detection of antibodies to bovine herpesvirus type 1

Three serological assays were compared for detection of antibodies to bovine herpes-virus type 1. These were virus neutralization (VN), enhanced complement fixation (CF) and enzyme-linked immunosorbent assay (ELISA). The ELISA was developed using an infected cell lysate antigen and purified virus and was optimized in relation to antigen and antisera dilutions. The CF assay was enhanced by the addition of bovine complement. These 3 assays were compared for detection of: specific virus antibody titers; sero-conversions; early antibody response in experimentally-infected cattle. Both ELISA end-point titers and single dilution values were found to be more sensitive than the CF or VN assays for specific antibody level quantitation. With a single dilution ELISA test procedure a correlation was obtained between ELISA values and VN titers. Using the single dilution ELISA test the assay also detected antibodies in experimentally-infected cattle before either the VN or CF assays, and agreed with the VN test in 35/38 seroconversions found by 4-fold or more VN changes between acute and convalescent paired sera from naturally-infected animals. The single dilution ELISA was a rapid and sensitive test for routine antibody detection in bovine sera.     

Induction of feline flea allergy dermatitis and the incidence and histopathological characteristics of concurrent indolent lip ulcers

The objectives of this study were to characterize the role of intermittent vs. continual flea exposure in the development of flea allergy dermatitis (FAD) in cats, assess the accuracy of intradermal skin testing (IDST) and in vitro testing, and document the incidence and histopathological features of indolent lip ulcers. Ten flea‐naive cats were divided into two groups. One group received intermittent flea exposure for 120 days. Thereafter, both groups of cats received continuous flea exposure for 120 days. In vitro testing for flea salivary antibody and IDST utilizing both whole flea antigen and flea salivary antigen were performed. Eight of 10 cats developed clinical signs of FAD within 3 months and five of these eight cats developed lip ulcers which where characterized histopathologically by ulceration with predominantly neutrophilic inflammation and surface bacterial colonization. There was no association between the presence or absence of clinical signs and positive IDST or in vitro results, and no difference in the development of clinical signs was noted between the two groups of cats.     

Prevalence of Feline Chlamydia psittaci and Feline Herpesvirus 1 in Cats with Upper Respiratory Tract Disease

The epidemiology of feline chlamydiosis and feline herpesvirus 1 (FHV1) infection in cats was determined using a duplex polymerase chain reaction assay. In cats with upper respiratory tract disease (URTD), prevalences of 66 (14.3%) of 462 cats and 98 (21.2%) of 462 cats were found for Chlamydia psittaci and FHV1, respectively. In cats without URTD, prevalences were 1/87 (1.1%) for both pathogens. Younger cats, cats sampled in summer, and cats with conjunctivitis were more likely to be positive for C psittaci than were cats sampled in other seasons and cats without conjunctivitis. Cats with recent contact with cats outside the household, cats with acute disease, and sneezing cats were more likely to be positive for FHV1 than were cats that had not had recent contact with cats outside the household, cats with chronic disease, and cats that were not sneezing. Purebred cats were less likely to be positive for FHV1 than were mixed breed cats and prevalence varied with year of sampling. Coinfection with both pathogens was lower than would be expected from their respective prevalences. Vaccinated cats were equally likely to be positive for FHV1 as unvaccinated cats. In sneezing cats FHV1 was more likely to be detected than C psittaci, particularly in acute cases, and when sneezing was not accompanied by conjunctivitis. Cats with reproductive disease concurrent with URTD were more likely to be infected with FHV1 than with C psittaci. Thus, the factors that should be considered in clinical diagnoses of C psittaci infections are the presence of conjunctivitis, age, and season, whereas contact with other cats, acute disease, and sneezing should be considered in diagnoses of FHV1 infection.     

Tear-film osmolarity in normal cats and cats with conjunctivitis

Objective To compare the tear‐film osmolarity of normal cats and cats with conjunctivitis. Animal studied The population consisted of shelter, research, and privately owned cats. Procedures Cats were classified as normal or having conjunctivitis. An ophthalmic examination including Schirmer tear test (STT), fluorescein staining, tear‐film break‐up time (TFBUT), intraocular pressure (IOP), and slit‐lamp biomicroscopy of the anterior segment was performed. The severity of conjunctivitis was graded and assigned a numerical score. The Tear Lab^TM Osmolarity System was utilized to determine the tear‐film osmolarity. Unpaired t‐tests were used to compare tear‐film osmolarity, TFBUT, IOP, and STT of the two groups. Results A total of 93 cats (186 eyes) were examined. There were 37 normal cats (74 eyes) and 39 conjunctivitis cats (78 eyes). The mean age was 2.34 years. There was no statistical difference (P = 0.2065) between the median tear‐film osmolarity of normal cats (328.5 ± 17.94 mOsms/L) and conjunctivitis cats (325.0 ± 24.84 mOsms/L). Cats with conjunctivitis had an accelerated TFBUT (P < 0.0001) and lower IOPs (P < 0.0001) as compared to normal cats. No statistical difference was found between STT values (P = 0.1304). Conclusions The median tear‐film osmolarity of normal cats was 328.5 mOsms/L. Despite the accelerated TFBUT, conjunctivitis did not cause a statistically significant change in tear‐film osmolarity. The Tear Lab^TM Osmolarity System was easily used and well tolerated by the cats in the study.     

Development of Clinical Signs and Occurrence of Feline Corona Virus Antigen in Naturally Infected Barrier Reared Cats and Their Offspring

The onset and pattern of the clinical signs of feline corona virus (FCoV) infection in cats were studied in a setting behind an isolation barrier. Two FCoV-seropositive cats were the source of the infection, and 3 barrier reared cats–initially FCoV-seronegative–were the recipients. The first clinical sign in the recipients appeared 11 days after contact with the source of infection. After 2 years 1 male and 1 female of the recipients started to breed. Their offspring developed clinical signs of disease at an age of 4-5 weeks. A pattern of recurring upper respiratory tract signs and conjunctivitis at intervals of about 4 months was observed in both the recipients and their offspring, while CNS dependent signs and wasting remained or got worse, once developed. Once demonstrated, FCoV antigen persisted in membrana nictitans throughout the investigation, and was found in all cats but 4 (90%). The offspring died during 2 periods, around the first week of life (9/37), and at 3-5 months of age (5/25). For comparison 3 offspring were euthanised at an age of 1 day and 16 offspring at an age of 3-6 months. FCoV antigen was demonstrated in all organs investigated (100%) from offspring dying during the first period, and in 97% from those dying during the second period. For the offspring euthanised during the same 2 periods the corresponding findings were 95% and 85%. Offspring euthanized between 9 and 17 months (4 kittens) had antigen in 67% of all investigated organs. The incidence of FCoV antigen in almost every organ in the investigated newborn kittens suggests an intrauterine infection. The demonstration of FCoV antigen in all euthanised cats, suggests a persistant infection. Virus was cultivated from membrana nictitans, that was FCoV antigen positive in the M3 test.     

Schirmer tear test values and tear film break-up times in cats with conjunctivitis

OBJECTIVES: (1) To document tear film break-up time (TFBUT) in a group of cats with conjunctivitis; (2) to determine if TFBUTs from cats with conjunctivitis vary significantly from previously established normal values for TFBUT in young cats without ocular disease; (3) to determine if a correlation exists between Schirmer tear test (STT) values and TFBUTs in cats with conjunctivitis; (4) to determine if the TFBUTs in cats with conjunctivitis are influenced by the detection of DNA from feline herpes virus-type 1 (FHV-1), Chlamydophila felis, Mycoplasma spp., and feline calicivirus. ANIMALS STUDIED: Fourteen cats between the ages of 0.8 years to 12 years with active, untreated conjunctivitis and without active keratitis or other ocular or systemic abnormalities were included in this study. Procedures Complete ophthalmic examinations, including TFBUT, were performed on all cats. Polymerase chain reaction (PCR) screening for FHV-1, Chlamydophila felis, Mycoplasma spp., and feline calicivirus was performed on conjunctival swabs from affected eyes and blood samples from all cats. RESULTS: Mean TFBUT for cats in this study was 8.9 (+/- 4.8) s in the right eye (OD) and 8.1 (+/- 4.6) s in the left eye (OS). No correlation existed between mean TFBUTs and mean STT values OD or OS. Conjunctival swabs from seven cats (n = 9 eyes) tested positive via PCR for one of the above infectious agents. Blood samples from nine cats tested positive for FHV-1. Mean TFBUTs for cats from which the DNA from FHV-1 was isolated from the blood were significantly lower than mean TFBUTs for cats from which no such DNA was isolated from the blood. CONCLUSIONS: In this study, the mean TFBUT in cats with conjunctivitis was significantly lower than previously established values for clinically healthy cats. This supports the theory that qualitative tear film deficiency, and thus tear film instability, may play a role in the pathogenesis of feline conjunctivitis. Qualitative tear film deficiency may predispose to the development of conjunctivitis or may occur secondarily to this condition.     

Isolation of Chlamydia psittaci from cases of conjunctivitis in a colony of cats

This report describes the isolation in cell cultures of Chlamydia psittaci from cases of conjunctivitis in a colony of cats. The organism was identified in McCoy cell monolayers by staining the intracytoplasmic chlamydial inclusions with a fluorescent antibody technique, and serological evidence of chlamydial infection in cats was obtained by indirect immunofluorescence. The possible role of C psittaci as an ocular, upper respiratory and reproductive tract pathogen in cats is discussed.     

Studies on the role of feline calicivirus in chronic stomatitis in cats.

Two groups of cats were inoculated oro-nasally with one of two isolates of feline calicivirus (FCV) from clinical cases of chronic stomatitis. All cats developed signs typical of acute FCV infection; namely, ocular and nasal discharge, conjunctivitis, and marked oral ulceration. None of the cats shed virus beyond 28 days. Seronegative control cats were then infected with a lower dose of one isolate, but again only acute signs were seen and no carriers produced. The original cats were then re-infected with the heterologous isolate. As before, only signs of acute disease were seen, but the range of clinical signs and severity was reduced. Virus shedding patterns in one group were similar to those seen originally, but in the other the duration was reduced. No chronic stomatitis developed over the 10 months of the study. Serum virus neutralising and serum and salivary class specific immunoglobulin responses were investigated. Although long-term carriers were not induced, no relationship between cessation of virus shedding in an individual animal and systemic and local antibody responses was seen.     

Transmission studies of Hendra virus (equine morbilli-virus) in fruit bats, horses and cats

Objective To determine the infectivity and transmissibility of Hendra virus (HeV). Design A disease transmission study using fruit bats, horses and cats. Procedure Eight grey-headed fruit bats (Pteropus poliocephalus) were inoculated and housed in contact with three uninfected bats and two uninfected horses. In a second exper iment, four horses were inoculated by subcutaneous injection and intranasal inoculation and housed in contact with three uninfected horses and six uninfected cats. In a third experi ment, 12 cats were inoculated and housed in contact with three uninfected horses. Two surviving horses were inoculated at the conclusion of the third experiment: the first orally and the second by nasal swabbing. All animals were necropsied and examined by gross and microscopic pathological methods, immunoperoxidase to detect viral antigen in formalin-fixed tissues, virus isolation was attempted on tissues and SNT and ELISA methods were used to detect HeV-specific antibody. Results Clinical disease was not observed in the fruit bats, although six of eight inoculated bats developed antibody against HeV, and two of six developed vascular lesions which contained viral antigen. The in-contact bats and horses did not seroconvert. Three of four horses that were inoculated devel oped acute disease, but in-contact horses and cats were not infected. In the third experiment, one of three in-contact horses contracted disease. At the time of necropsy, high titres of HeV were detected in the kidneys of six acutely infected horses, in the urine of four horses and the mouth of two, but not in the nasal cavities or tracheas. Conclusions Grey-headed fruit bats seroconvert and develop subclinical disease when inoculated with HeV. Horses can be infected by oronasal routes and can excrete HeV in urine and saliva. It is possible to transmit HeV from cats to horses. Transmission from P poliocephalus t o horses could not be proven and neither could transmission from horses to horses or horses to cats. Under the experimental conditions of the study the virus is not highly contagious.     

Feline chlamydiosis

Chlamydiae are an important cause of acute and chronic conjunctivitis in cats. Until recently, only one organism was thought to infect cats, Chlamydophila felis (previously Chlamydia psittaci var. felis). Recently, other Chlamydia-like organisms belonging to the family Parachlamydiaceae, which comprises organisms that reside and proliferate within free-living amoeba, have been identified in cats with neutrophilic and eosinophilic conjunctivitis. The relative importance of these organisms and their amoebic hosts requires investigation. There is also weak evidence that chlamydiae may also be capable of causing reproductive tract disease and lameness in cats. Diagnosis of chlamydial conjunctivitis requires use of specialized culture techniques or the polymerase chain reaction. The antibiotic of choice to treat these infections is doxycycline; azithromycin is less effective. All cats in the household should be treated simultaneously. The zoonotic potential of these organisms appears low, but some precaution is warranted when handling affected cats.     

Detection of Chlamydia psittaci from various animal species by reverse passive haemagglutination

A reverse passive haemagglutination test (RPH) has previously been developed to detect the genus-specific antigen of Chlamydia. Clinical samples were obtained from various sites of different animal species. The RPH test detected chlamydial antigen from clinical cases of conjunctivitis in cats, abortion in sheep and psittacosis in birds. Although not as sensitive as cell culture isolation, this test has the advantages of rapidity and of detecting antigen from dead chlamydiae.     

Use of imiquimod 5% cream (Aldara™) in cats with multicentric squamous cell carcinoma in situ: 12 cases (2002–2005)*

Multicentric squamous cell carcinoma in situ (MSCCIS) is a variant of squamous cell carcinoma in cats, commonly referred to as Bowen’s‐like disease. Imiquimod 5% cream (Aldara?) is a novel immune response modifier (IRM) that has been reported as a successful treatment for Bowen’s disease in humans. The purpose of this study was to describe clinical findings, treatment protocols and survival in cats with MSCCIS treated with imiquimod 5% cream and to examine the effects of imiquimod 5% cream in cats with MSCCIS. The expression of papillomavirus group‐specific antigen in the study population was also determined. From review of medical records, 12 cats were identified with a histologic diagnosis of MSCCIS and treatment with imiquimod 5% cream. Initial lesions responded to imiquimod 5% cream in all cats. Most cats (75%) developed new lesions. New lesions also responded to imiquimod 5% cream in all cats treated. Five cats (41%) had side effects suspected to be associated with the use of imiquimod 5% cream, including local erythema (25%), increased liver enzymes and neutropenia (8%), and partial anorexia and vomiting (8%). Kaplan–Meier median treatment duration and median survival time probabilities for cats in this study were 1189 days, respectively. A time to failure model was generated as many cats were censored from analysis well before the aforementioned projected median. This model resulted in a shorter median survival time of 243 days. No patient‐related, tumour‐related or treatment‐related prognostic variables were identified. No expression for papilloma group‐specific antigen was found. Imiquimod 5% cream appears to be well tolerated in the majority of cats, and further studies are warranted to further examine its usefulness in cats with this disease.     

Chlamydophila felis in Cats – Are the Stray Cats Dangerous Source of Infection?

Chlamydophila felis is a causative agent of acute or chronic conjunctivitis, and pneumonia in cats. Natural transmission mostly occurs consequently to close contact with other infected cats, their aerosol and fomites. We have examined 93 cats with symptoms of acute or chronic conjunctivitis, from Ko?ice region in Slovakia, during the period of 2 years. Conjunctival samples were obtained from 55 domestic cats (59.14%) and 38 stray cats (40.86%). Of the total number of 93 examined animals, 42 cats were positive, which represents 45.16% overall positivity. Out of the 42 positive cats, 25 cats were stray and 17 positive cats were classified as domestic, which means that of 38 stray cats, 25 were positive (which represented 65.78% positivity) and of 55 domestic cats, 17 were positive (positivity was 30.90%). Our results showed that cats, especially stray cats, could be a dangerous source of chlamydiosis for humans.