Clinical aspects of Chlamydia psittaci infection in cats infected with feline immunodeficiency virus

A review of evidence-based management of infectious ocular surface disease in shelter-housed domestic cats

Infectious ocular surface disease (IOSD) is a common problem in shelter-housed domestic cats and has a widespread negative impact on animal welfare. While the common etiological agents are well-described, addressing IOSD in large groups of animals presents a management challenge to the clinician and logistical challenges to shelter employees. Treatments, diagnostics, and prevention strategies that are effective in privately owned or experimental animals may be impractical or ineffective in the shelter environment. This review article focuses on the relative prevalence of etiological agents in feline IOSD, practical diagnostic testing protocols, prevention strategies, and treatment of IOSD in shelter-housed cats. Discrepancies between experimental laboratory-based studies and clinical trials assessing therapeutics for treatment of feline herpes virus are highlighted. Further high-quality clinical trials are necessary to determine optimal preventative and therapeutic protocols for IOSD in shelter-housed cats.

Vaccination against the Koala Retrovirus (KoRV): Problems and Strategies

The koala retrovirus (KoRV) is spreading in the koala population from the north to the south of Australia and is also in the process of endogenization into the koala genome. Virus infection is associated with tumorigenesis and immunodeficiency and is contributing to the decline of the animal population. Antibody production is an excellent marker of retrovirus infection; however, animals carrying endogenous KoRV are tolerant. Therefore, the therapeutic immunization of animals carrying endogenous KoRV seems to be ineffective. Using the recombinant transmembrane (TM) envelope protein of the KoRV, we immunized goats, rats and mice, obtaining in all cases neutralizing antibodies which recognize epitopes in the fusion peptide proximal region (FPPR), and in the membrane-proximal external region (MPER). Immunizing several animal species with the corresponding TM envelope protein of the closely related porcine endogenous retrovirus (PERV), as well as the feline leukemia virus (FeLV), we also induced neutralizing antibodies with similar epitopes. Immunizing with the TM envelope protein in addition to the surface envelope proteins of all three viruses resulted in higher titers of neutralizing antibodies. Immunizing KoRV-negative koalas with our vaccine (which is composed of both envelope proteins) may protect these animals from infection, and these may be the starting points of a virus-free population.

Occurrence of Chlamydiaceae and Chlamydia felis pmp9 Typing in Conjunctival and Rectal Samples of Swiss Stray and Pet Cats

Chlamydia (C.) felis primarily replicates in feline conjunctival epithelial cells and is an important cause of conjunctivitis in cats. Data on C. felis infection rates in stray cats in Switzerland has been missing so far. We performed a qPCR-based Chlamydiaceae-screening on 565 conjunctival and 387 rectal samples from 309 stray and 86 pet cats followed by Chlamydia species identification and C. felis typing using the gene pmp9, which encodes a polymorphic membrane protein. Overall, 19.1% of the stray and 11.6% of the pet cats were Chlamydiaceae-positive with significantly higher rates in cats displaying signs of conjunctivitis (37.1%) compared to healthy animals (6.9%). Rectal shedding of Chlamydiaceae occurred in 25.0% of infected cats and was mostly associated with concurrent ocular positivity (87.5%). In 92.2% of positive conjunctival and rectal samples, the Chlamydia species was identified as C. felis and in 2.6% as C. abortus. The C. felis pmp9 gene was very conserved in the sampled population with only one single-nucleotide polymorphism (SNP) in one conjunctival sample. In conclusion, C. felis strains are circulating in Swiss cats, are associated with conjunctivitis, have a low pmp9 genetic variability, and are rectally shed in about 16% of positive cases.

Koala immunology and infectious diseases: How much can the koala bear?

Infectious diseases are contributing to the decline of the iconic Australian marsupial, the koala (Phascolarctos cinereus). Infections with the obligate intracellular bacteria, Chlamydia pecorum, cause debilitating ocular and urogenital-tract disease while the koala-retrovirus (KoRV) has been implicated in host immunosuppression and exacerbation of chlamydial pathogenesis. Although histological studies have provided insight into the basic architecture of koala immune tissues, our understanding of the koala immune response to infectious disease has been limited, until recently, by a lack of species-specific immune reagents. Recent advances in the characterisation of key immune genes have focused on advancing our understanding of the immune response to Chlamydia infection, revealing commonalities in disease pathologies and immunity between koalas and other hosts and paving the way for the development of a koala Chlamydia vaccine. This review summarises these recent findings and highlights key aspects of the koala immune system requiring further attention with particular regard to their most prominent infectious diseases.

Infection with koala retrovirus subgroup B (KoRV-B), but not KoRV-A, is associated with chlamydial disease in free-ranging koalas (Phascolarctos cinereus)

The virulence of chlamydial infection in wild koalas is highly variable between individuals. Some koalas can be infected (PCR positive) with Chlamydia for long periods but remain asymptomatic, whereas others develop clinical disease. Chlamydia in the koala has traditionally been studied without regard to coinfection with other pathogens, although koalas are usually subject to infection with koala retrovirus (KoRV). Retroviruses can be immunosuppressive, and there is evidence of an immunosuppressive effect of KoRV in vitro. Originally thought to be a single endogenous strain, a new, potentially more virulent exogenous variant (KoRV-B) was recently reported. We hypothesized that KoRV-B might significantly alter chlamydial disease outcomes in koalas, presumably via immunosuppression. By studying sub-groups of Chlamydia and KoRV infected koalas in the wild, we found that neither total KoRV load (either viraemia or proviral copies per genome), nor chlamydial infection level or strain type, was significantly associated with chlamydial disease risk. However, PCR positivity with KoRV-B was significantly associated with chlamydial disease in koalas (p = 0.02961). This represents an example of a recently evolved virus variant that may be predisposing its host (the koala) to overt clinical disease when co-infected with an otherwise asymptomatic bacterial pathogen (Chlamydia).

Detection of koala retrovirus subgroup B (KoRV-B) in animals housed at European zoos

Many koalas carry an endogenous retrovirus, KoRV-A, in their genome. Recently, a second retrovirus, KoRV-B, was detected in koalas in Japanese and U.S. zoos. However, this virus is not endogenous, differs in the receptor binding site of the surface envelope protein, and uses a receptor different from that of KoRV-A. We describe here a KoRV-B found in koalas at zoos in Germany and Belgium that differs slightly from that found in the Los Angeles zoo.

Koala retroviruses: characterization and impact on the life of koalas

Koala retroviruses (KoRV) have been isolated from wild and captive koalas in Australia as well as from koala populations held in zoos in other countries. They are members of the genus Gammaretrovirus, are most closely related to gibbon ape leukemia virus (GaLV), feline leukemia virus (FeLV) and porcine endogenous retrovirus (PERV) and are likely the result of a relatively recent trans-species transmission from rodents or bats. The first KoRV to be isolated, KoRV-A, is widely distributed in the koala population in both integrated endogenous and infectious exogenous forms with evidence from museum specimens older than 150 years, indicating a relatively long engagement with the koala population. More recently, additional subtypes of KoRV that are not endogenized have been identified based on sequence differences and host cell receptor specificity (KoRV-B and KoRV-J). A specific association with fatal lymphoma and leukemia has been recently suggested for KoRV-B. In addition, it has been proposed that the high viral loads found in many animals may lead to immunomodulation resulting in a higher incidence of diseases such as chlamydiosis. Although the molecular basis of this immunomodulation is still unclear, purified KoRV particles and a peptide corresponding to a highly conserved domain in the envelope protein have been shown to modulate cytokine expression in vitro, similar to that induced by other gammaretroviruses. While much is still to be learned, KoRV induced lymphoma/leukemia and opportunistic disease arising as a consequence of immunomodulation are likely to play an important role in the stability of koala populations both in the wild and in captivity.

Construction and characterization of an infectious molecular clone of Koala retrovirus

Koala retrovirus (KoRV) is a gammaretrovirus that is currently endogenizing into koalas. Studies on KoRV infection have been hampered by the lack of a replication-competent molecular clone. In this study, we constructed an infectious molecular clone, termed plasmid pKoRV522, of a KoRV isolate (strain Aki) from a koala reared in a Japanese zoo. The virus KoRV522, derived from pKoRV522, grew efficiently in human embryonic kidney (HEK293T) cells, attaining 10(6) focus-forming units/ml. Several mutations in the Gag (L domain) and Env regions reported to be involved in reduction in viral infection/production in vitro are found in pKoRV522, yet KoRV522 replicated well, suggesting that any effects of these mutations are limited. Indeed, a reporter virus pseudotyped with pKoRV522 Env was found to infect human, feline, and mink cell lines efficiently. Analyses of KoRV L-domain mutants showed that an additional PPXY sequence, PPPY, in Gag plays a critical role in KoRV budding. Altogether, our results demonstrate the construction and characterization of the first infectious molecular clone of KoRV. The infectious clone reported here will be useful for elucidating the mechanism of endogenization of the virus in koalas and screening for antiretroviral drugs for KoRV-infected koalas.

Multilocus variable-number tandem-repeat analysis scheme for chlamydia felis genotyping: comparison with multilocus sequence typing

Chlamydia felis is an important ocular pathogen in cats worldwide. A multilocus variable-number tandem-repeat analysis (MLVA) system for the detection of tandem repeats across the whole genome of C. felis strain Fe/C-56 was developed. Nine selected genetic loci were tested by MLVA in 17 C. felis isolates, including the C. felis Baker vaccine strain, and 122 clinical samples from different geographic origins. Analysis of the results identified 25 distinct C. felis MLVA patterns. In parallel, a recently described multilocus sequence typing scheme for the typing of Chlamydia was applied to 13 clinical samples with 12 different C. felis MLVA patterns. Rare sequence differences were observed. Thus, the newly developed MLVA system provides a highly sensitive high-resolution test for the differentiation of C. felis isolates from different origins that is suitable for molecular epidemiological studies.

Infection barriers to successful xenotransplantation focusing on porcine endogenous retroviruses

Xenotransplantation may be a solution to overcome the shortage of organs for the treatment of patients with organ failure, but it may be associated with the transmission of porcine microorganisms and the development of xenozoonoses. Whereas most microorganisms may be eliminated by pathogen-free breeding of the donor animals, porcine endogenous retroviruses (PERVs) cannot be eliminated, since these are integrated into the genomes of all pigs. Human-tropic PERV-A and -B are present in all pigs and are able to infect human cells. Infection of ecotropic PERV-C is limited to pig cells. PERVs may adapt to host cells by varying the number of LTR-binding transcription factor binding sites. Like all retroviruses, they may induce tumors and/or immunodeficiencies. To date, all experimental, preclinical, and clinical xenotransplantations using pig cells, tissues, and organs have not shown transmission of PERV. Highly sensitive and specific methods have been developed to analyze the PERV status of donor pigs and to monitor recipients for PERV infection. Strategies have been developed to prevent PERV transmission, including selection of PERV-C-negative, low-producer pigs, generation of an effective vaccine, selection of effective antiretrovirals, and generation of animals transgenic for a PERV-specific short hairpin RNA inhibiting PERV expression by RNA interference.

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.

Chlamydophila felis infection. ABCD guidelines on prevention and management

OVERVIEW

Chlamydophila felis is a Gram-negative bacterium and its primary target is the conjunctiva. The bacterium does not survive outside the host.

INFECTION

Transmission requires close contact between cats; ocular secretions are probably the most important body fluid for infection. Most cases occur in cats under 1 year of age. Chlamydophila felis is the infectious organism most frequently associated with conjunctivitis.

DISEASE SIGNS

Unilateral ocular disease generally progresses to become bilateral. There can be intense conjunctivitis with extreme hyperaemia of the nictitating membrane, blepharospasm and ocular discomfort. Transient fever, inappetence and weight loss may occur shortly after infection, although most cats remain well and continue to eat.

DIAGNOSIS

PCR techniques are now preferred for diagnosing C felis infection. Ocular swabs are generally used. In unvaccinated cats, antibody detection can be used to indicate infection.

DISEASE MANAGEMENT

Tetracyclines are generally regarded as the antibiotics of choice. Doxycycline has the advantage of requiring only single daily administration and is given at a dose of 10 mg/kg orally. Vaccination should be considered if there is a history of confirmed chlamydial disease in a shelter. Single housing and routine hygiene measures should suffice to avoid cross-infection. Cats maintained together for longer terms should be vaccinated regularly. In breeding catteries where C felis infection is endemic, the first step should be to treat all cats with doxycycline for at least 4 weeks. Once clinical signs have been controlled, the cats should be vaccinated.

VACCINATION RECOMMENDATIONS

Vaccination should be considered for cats at risk of exposure to infection. Vaccination generally begins at 8-10 weeks of age, with a second injection 3-4 weeks later. Annual boosters are recommended for cats at continued risk of exposure.

Transspecies transmission of the endogenous koala retrovirus

The koala retrovirus (KoRV) is a gammaretrovirus closely related to the gibbon ape leukemia virus and induces leukemias and immune deficiencies associated with opportunistic infections, such as chlamydiosis. Here we characterize a KoRV newly isolated from an animal in a German zoo and show infection of human and rat cell lines in vitro and of rats in vivo, using immunological and PCR methods for virus detection. The KoRV transmembrane envelope protein (p15E) was cloned and expressed, and p15E-specific neutralizing antibodies able to prevent virus infection in vitro were developed. Finally, evidence for immunosuppressive properties of the KoRV was obtained.

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.

Real-time reverse transcriptase PCR for the endogenous koala retrovirus reveals an association between plasma viral load and neoplastic disease in koalas

Koala retrovirus (KoRV) is a newly described endogenous retrovirus and is unusual in that inserts comprise a full-length replication competent genome. As koalas are known to suffer from an extremely high incidence of leukaemia/lymphoma, the association between this retrovirus and disease in koalas was examined. Using quantitative real-time reverse transcriptase PCR it was demonstrated that KoRV RNA levels in plasma are significantly increased in animals suffering from leukaemia or lymphoma when compared with healthy animals. Increased levels of KoRV were also seen for animals with clinical chlamydiosis. A significant positive association between viral RNA levels and age was also demonstrated. Real-time PCR demonstrated as much as 5 log variation in KoRV proviral DNA levels in genomic DNA extracted from whole blood from different animals. Taken together these data indicate that KoRV is an active endogenous retrovirus and suggests that it may be causally linked to neoplastic disease in koalas.

Efficacy of azithromycin for the treatment of feline chlamydophilosis

The current recommended treatment for feline chlamydophilosis involves daily oral administration of antimicrobials to all cats within an affected group for a prolonged period of time (4-6 weeks). Not surprisingly, owner compliance can be poor resulting in apparent treatment failure. Recent anecdotal evidence, supported by its efficacy in the treatment of Chlamydia trachomatis infection in humans, has suggested that azithromycin may offer an alternative by allowing less frequent dosing for a shorter duration. A clinical trial was designed to evaluate the efficacy of azithromycin for the treatment of chlamydia (Chlamydophila felis) infection in cats. Whilst azithromycin, given at 10-15 mg/kg daily for 3 days and then twice weekly, provided a similar, rapid resolution of clinical signs and negative isolation scores as doxycycline, C felis was re-isolated in four out of the five cats treated. Furthermore, even daily administration of azithromycin to chronically infected cats was ineffective in clearing infection. The azithromycin protocols used here were therefore found to be unsuccessful in eliminating the carriage of this strain of C felis.

Experimental infection of cats with Chlamydophila felis

Cats experimentally infected with a British isolate of Chlamydophila felis (C. felis), B166 strain, by droplet into the eye and nose developed conjunctivitis, mild rhinitis and fever. The chlamydophila were first isolated from conjunctiva, nictitating membrane and then from lung, tonsil, liver, spleen, kidney, nasal and vaginal swabs and blood. These results indicate that C. felis B166 strain first infected and replicated in the conjunctiva and nictitating membrane in cats with symptoms which were mostly limited to conjunctivitis, and then pervaded the whole body by bacteremia.

Relationships between clinical and pathological signs of disease in calves infected with Mannheimia (Pasteurella) haemolytica type A1

Respiratory disease was induced in 16 calves, and the terminal clinical signs of disease and postmortem pathological observations were recorded. By Spearman's correlation coefficient, the respiratory rate, rectal temperature and clinical scores of the calves were significantly correlated with the extent of lung consolidation. The respiratory rate was the clinical sign most consistently correlated with the other clinical and pathological signs of respiratory disease.

Feline leukemia virus and feline immunodeficiency virus

Ophthalmic manifestations of FeLV or FIV infection can occur in all ocular tissues and may be manifestations of direct viral effects or secondary to viral-related malignant transformation. Additionally, the manifestations of common feline ophthalmic pathogens may be more severe and poorly responsive to therapy because of the immunosuppressive effects of FeLV or FIV infection. Prompt diagnosis of underlying viral infection in cats with ophthalmic disease is paramount for accurate diagnosis and prognosis and is required for appropriate therapeutic decision making.

Feline chlamydia and calicivirus infections

Feline conjunctivitis is common and often presents a clinical challenge to the veterinarian. Chlamydia psittaci is an important pathogen and should always be considered when evaluating cats with conjunctivitis. FCV is an infrequent cause of conjunctivitis and only causes the disease in conjunction with other clinical signs of this infection, such as oral mucosal ulcers and upper respiratory tract disease.

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.

The clinical efficacy of topical and systemic therapy for the treatment of feline ocular chlamydiosis

Twenty-four specific-pathogen-free-derived cats aged four to 11 months were challenged by ocular application of a field isolate of Chlamydia psittaci to evaluate the effect of topical and systemic therapy on the course of disease. The cats were monitored for 35 days post-challenge, with severity of clinical signs being measured using a scoring system, and ocular shedding of the organism monitored by culture of conjunctival swabs. All cats developed active C psittaci infection, and after 7 days the cats were randomly assigned to one of four treatment groups: Group P (placebo) was given twice-daily ophthalmic tear-replacement ointment; group F was given twice-daily topical 1% fusidic acid ophthalmic viscous drops; group C was given twice-daily topical 1% chlortetracycline ophthalmic ointment; and group D was given doxycycline at 10 mg/kg daily per os in addition to twice-daily topical 1% fusidic acid ophthalmic ointment. Within 24 h of commencement of therapy, group D had significantly lower median clinical scores than group P, and with the exception of day 16, this trend was maintained throughout the observation period. Median clinical scores of cats in group F were not appreciably different to those in group P, whereas the median scores of cats in group C generally fell between those of groups P and D. The median duration of C psittaci shedding was 10 and 15 days for groups D and C respectively, but four of the six cats in groups F and P were still shedding organisms at the end of the study (day 35). In this study, systemic therapy with doxycycline proved superior to topical therapy in the treatment of feline chlamydiosis.

Feline immunodeficiency virus infection: an overview

In 1987, Pedersen et al. (1987) reported the isolation of a T-lymphotropic virus possessing the characteristics of a lentivirus from pet cats in Davis, California. From the first report onwards, it was evident that in causing an acquired immunodeficiency syndrome in cats, the virus was of substantial veterinary importance. It shares many physical and biochemical properties with human immunodeficiency virus (HIV), and was therefore named feline immunodeficiency virus (FIV). This article reviews recent knowledge of the aetiology, epidemiology, pathogenesis, clinical signs, diagnosis, prevention, and treatment options of FIV infection.

Characterization of the systemic disease and ocular signs induced by experimental infection with Chlamydia psittaci in cats

In addition to the commonly reported ocular signs, Chlamydia psittaci infection of kittens resulted in fever, lethargy, lameness and reduction in weight gain following ocular instillation of virulent organisms. The appearance of these systemic signs was late with respect to the appearance of ocular symptoms and occurred simultaneously with increasing levels of chlamydia-specific IgG. Measurement of acute phase reactants and IL-6 in plasma indicated that both became elevated concurrent with or slightly after the appearance of fever and remained elevated after the fever began to resolve. Preliminary data also indicated that infectious C. psittaci was present in the blood stream during this time period. The results of ocular instillation of three different levels of C. psittaci (10(3.8), 10(2.8) and 10(1.5) TCID50) indicated that the frequency of infection and the severity of ocular signs were diminished in the group receiving the lowest dose. However, the magnitude of systemic disease was similar in all animals which exhibited clinical signs, irrespective of the dose administered. The immune response to infection included elementary body (EB)-specific lymphocyte proliferation as well as the development of EB-specific IgG and IgM antibodies. The predominant antibody response was to a 45 kDa protein, the major outer membrane protein (MOMP), lipopolysaccharide (LPS), a 58 kDa doublet and 32 and 16-19 kDa proteins.

Parasite prevalence in free-ranging farm cats, Felis silvestris catus

No animals tested were positive for feline leukemia virus antigen and Chlamydia psittaci antibodies, but all were positive for antibodies to feline calicivirus (FCV), feline herpesvirus 1 (FHV1) and rotavirus. They had antibodies to feline parvovirus (96%), feline coronavirus (84% and cowpox virus (2%). Antibody to feline immunodeficiency virus (FIV) was found in 53% of animals, which were less likely to be infected with Haemobartonella felis, and had higher FHV antibody titres than cats without FIV. FCV was isolated from 51% cats and FHV1 and feline reovirus each from 4%. H. felis was present in 42% of animals, and antibody to Toxoplasma gondii in 62%. Clinical abnormality had a significant association with FIV and feline calicivirus infections, but sex, age, social status and feeding group had no significant association with prevalence of any parasites. Toxocara cati and Toxascaris leonina eggs were found, respectively, in 91% and 82% of animals tested.

Chlamydiainfection 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.