Prevalence, risk factors and genetic diversity of Chlamydia felis in cats

Szymańska-Czerwińska, Monika; Zaręba-Marchewka, Kinga; Woś, Michał; Balicki, Ireneusz; Zwolska, Jowita; Kuduk, Barbara; Niemczuk, Krzysztof

doi:10.2478/jvetres-2025-0074

Abstract

Introduction

Chlamydia felis is the main chlamydial pathogen of cats and is associated with conjunctivitis and respiratory disease. This study aimed to estimate the prevalence of Chlamydiaceae and Chlamydia felis, to explore risk factors and predictors (age, sex, breed, origin and ocular signs) for infection using logistic regression, and to appraise genetic diversity via ompA sequencing and phylogenetic analysis.

Material and Methods

Conjunctival swabs from 156 cats were examined using real-time PCR assays for Chlamydiaceae and C. felis. Logistic regression and Kaplan–Meier analysis evaluated risk factors, and partial ompA sequences were phylogenetically analysed.

Results

Chlamydiaceae DNA was detected in 7.7% (12/156) of cats and was identified as C. felis. Infections were mostly unilateral. Threshold cycle values varied widely, suggesting heterogeneous bacterial loads. Younger age was a significant risk factor, and the probability of infection decreased steadily with age. Ocular signs strongly predicted infection. British Shorthair/Longhair cats had more than threefold higher odds of infection than European Shorthair cats. Phylogenetic analysis of ompA showed very high genome conservation (99.7–100%), which was consistent with global data.

Conclusion

This first molecular study of C. felis in Poland in ten years demonstrates that infection mainly affects young, purebred cats with apparent conjunctivitis. The genetic stability of ompA supports the concept of a globally homogeneous C. felis population.

References

Bellinati L., Ceglie L., Mazzotta E., Campalto M., Lucchese L., Natale A.: One-year surveillance of Chlamydia spp. infection in stray cats from northeastern Italy. Front Vet Sci 2025, 17, 12, 1502642, doi: 10.3389/fvets.2025.1502642.
Open DOI Search in Google Scholar Back to article
Borel N., Sachse K.: Zoonotic transmission of Chlamydia spp.: known for 140 years, but still underestimated. In: Zoonoses: Infections affecting humans and animals, edited by A. Sing, Springer International Publishing, Cham, Switzerland, 2023, pp. 793–819, doi: 10.1007/978-3-030-85877-3_53-1.
Open DOI Search in Google Scholar Back to article
Bressan M., Rampazzo A., Kuratli J., Marti H., Pesch T., Borel N.: Occurrence of Chlamydiaceae and Chlamydia felis Pmp9 typing in conjunctival and rectal samples of Swiss stray and pet cats. Pathogens 2021, 10, 951, doi: 10.3390/pathogens10080951.
Open DOI Search in Google Scholar Back to article
Cai Y., Fukushi H., Koyasu S., Kuroda E., Yamaguchi T., Hirai K.: An etiological investigation of domestic cats with conjunctivitis and upper respiratory tract disease in Japan. J Vet Med Sci 2002, 64, 215–219, doi: 10.1292/jvms.64.215.
Open DOI Search in Google Scholar Back to article
Chan I., Dowsey A., Lait P., Tasker S., Blackwell E., Helps C.R., Barker E.N.: Prevalence and risk factors for common respiratory pathogens within a cohort of pet cats in the UK. J Small Anim Pract 2023, 64, 552–560, doi: 10.1111/jsap.13623.
Open DOI Search in Google Scholar Back to article
Denamur E., Sayada C., Souriau A., Orfila J., Rodolakis A., Elion J.: Restriction pattern of the major outer-membrane protein gene provides evidence for a homogeneous invasive group among ruminant isolates of Chlamydia psittaci. J Gen Microbiol 1991, 137, 2525–2530, doi: 10.1099/00221287-137-11-2525.
Open DOI Search in Google Scholar Back to article
Di Francesco A., Baldelli R.: Feline chlamydiosis in Italy: PCR amplification and analysis of the ompA and groEL-homolog genes. New Microbiol 2002, 25, 341–344.
Search in Google Scholar Back to article
Ehricht R., Slickers P., Goellner S., Hotzel H., Sachse K.: Optimized DNA microarray assay allows detection and genotyping of single PCR-amplifiable target copies. Mol Cell Probes 2006, 20, 60–63, doi: 10.1016/j.mcp.2005.09.003.
Open DOI Search in Google Scholar Back to article
Everett K.D.E., Bush R.M., Andersen A.A.: Emended description of the order Chlamydiales, proposal of Parachlamydiaceae fam. nov. and Simkaniaceae fam. nov., each containing one monotypic genus, revised taxonomy of the family Chlamydiaceae, including a new genus and five new species, and standards. Int J Syst Evol Microbiol 1999, 49, 415–440, doi: 10.1099/0020771349-2-415.
Open DOI Search in Google Scholar Back to article
Ghasemian A., Pezeshki B., Memariani M., Mahmoodi S., Kohansal M., Rajabi-Vardanjani H.: The emergence potential of Chlamydia psittaci and Chlamydia felis as zoonotic agents causing ocular and respiratory infections in humans and animals. Arch Razi Inst 2024, 79, 685–694, doi: 10.32592/ARI.2024.79.4.685.
Open DOI Search in Google Scholar Back to article
Halánová M., Petrová L., Halán M., Trbolová A., Babinská I., Weissová T.: Impact of way of life and environment on the prevalence of Chlamydia felis in cats as potentional sources of infection for humans. Ann Agric Environ Med 2019, 26, 222–226, doi: 10.26444/aaem/100655.
Open DOI Search in Google Scholar Back to article
Halánová M., Sulinová Z., Čisláková L., Trbolová A., Páleník L., Weissová T., Halán M., Kalinová Z., Holičková M.: Chlamydophila felis in cats – are the stray cats dangerous source of infection? Zoonoses Public Health 2011, 58, 519–522, doi: 10.1111/j.1863-2378.2011.01397.x.
Open DOI Search in Google Scholar Back to article
Hoang D., Chernomor O., von Haeseler A., Minh B., Vinh L.: UFBoot2: Improving the Ultrafast Bootstrap Approximation. Mol Biol Evol 2018, 35, 518–522, doi: 10.1093/molbev/msx281.
Open DOI Search in Google Scholar Back to article
Hunter J.D.: Matplotlib: A 2D graphics environment. Comp Sci Eng 2007, 9, 90–95, doi: 10.1109/MCSE.2007.55.
Open DOI Search in Google Scholar Back to article
Kalyaanamoorthy S., Minh B.Q., Wong T.K.F., von Haeseler A., Jermiin L.S.: ModelFinder: fast model selection for accurate phylogenetic estimates. Nat Methods 2017, 14, 587–589, doi: 10.1038/nmeth.4285.
Open DOI Search in Google Scholar Back to article
Katoh K., Misawa K., Kuma K., Miyata T.: MAFFT: a novel method for rapid multiple sequence alignment based on fast Fourier transform. Nucleic Acids Res 2002, 30, 3059–3066, doi: 10.1093/nar/gkf436.
Open DOI Search in Google Scholar Back to article
Laroucau K., Aaziz R., Meurice L., Servas V., Chossat I., Royer H., De Barbeyrac B., Vaillant V., Moyen J., Meziani F., Sachse K., Rolland P.: Outbreak of psittacosis in a group of women exposed to Chlamydia psittaci-infected chickens. Euro Surveill 2015, 20, 21155, doi: 10.2807/1560-7917.ES2015.20.24.21155.
Open DOI Search in Google Scholar Back to article
Letunic I., Bork P.: Interactive Tree Of Life (iTOL) v5: an online tool for phylogenetic tree display and annotation. Nucleic Acids Res 2021, 49, W293–W296, doi: 10.1093/nar/gkab301.
Open DOI Search in Google Scholar Back to article
Madani S.A., Peighambari S.M.: PCR-based diagnosis, molecular characterization and detection of atypical strains of avian Chlamydia psittaci in companion and wild birds. Avian Pathol 2013, 42, 38–44, doi: 10.1080/03079457.2012.757288.
Open DOI Search in Google Scholar Back to article
McKinney W.: Data structures for statistical computing in Python. Proceedings of the Ninth Python in Science Conference, 28 June–3 July 2010, Austin, TX, USA, doi: 10.25080/Majora-92bf1922- 00a.
Open DOI Search in Google Scholar Back to article
Menard A., Clerc M., Subtil A., Megraud F., Bebear C., de Barbeyrac B.: Development of a real-time PCR for the detection of Chlamydia psittaci. J Med Microbiol 2006, 55, 471–473, doi: 10.1099/jmm.0.46335-0.
Open DOI Search in Google Scholar Back to article
Nguyen L.T., Schmidt H.A., von Haeseler A., Minh B.Q.: IQ-TREE: a fast and effective stochastic algorithm for estimating maximum-likelihood phylogenies. Mol Biol Evol 2015, 32, 268–274, doi: 10.1093/molbev/msu300.
Open DOI Search in Google Scholar Back to article
Pantchev A., Sting R., Bauerfeind R., Tyczka J., Sachse K.: Detection of all Chlamydophila and Chlamydia spp. of veterinary interest using species-specific real-time PCR assays. Comp Immunol Microbiol Infect Dis 2010, 33, 473–484, doi: 10.1016/j.cimid.2009.08.002.
Open DOI Search in Google Scholar Back to article
Pedregosa F., Varoquaux G., Gramfort A., Michel V., Thirion B., Grisel O., Blondel M., Prettenhofer P., Weiss R., Dubourg V., Vanderplas J., Passos A., Cournapeau D., Brucher M., Perrot M., Duchenay É.: Scikit-learn: machine learning in Python. J Mach Learn 2011, 12, 2825–2330.
Search in Google Scholar Back to article
Płoneczka-Janeczko K., Kiełbowicz Z., Kuczkowski M.: First molecular characterisation and identification of a Chlamydophila felis from urban cats in Wroclaw, Poland. Bull Vet Inst Pulawy 2011, 55, 193–198.
Search in Google Scholar Back to article
Sanderson H., Vasquez M., Killion H., Vance M., Sondgeroth K., Fox J.: Fatal Chlamydia psittaci infection in a domestic kitten. J Vet Diagn Invest 2021, 33, 101–103, doi: 10.1177/1040638720966960.
Open DOI Search in Google Scholar Back to article
Sandmeyer L.S., Lucyshyn D.R., Osinchuk S.: Diagnostic Ophthalmology. Can Vet J 2021, 62, 1007–1010.
Search in Google Scholar Back to article
Sibitz C., Rudnay E.C., Wabnegger L., Spergser J., Apfalter P., Nell B.: Detection of Chlamydophila pneumoniae in cats with conjunctivitis. Vet Ophthalmol 2011, 14, 67–74, doi: 10.1111/j.1463-5224.2011.00919.x.
Open DOI Search in Google Scholar Back to article
Šoštarić-Zuckermann I.C., Borel N., Kaiser C., Grabarević Ž., Pospischil A.: Chlamydia in canine or feline coronary arteriosclerotic lesions. BMC Res Notes 2011, 4, 350, doi: 10.1186/1756-0500-4-350.
Open DOI Search in Google Scholar Back to article
Sykes J.E.: Feline chlamydiosis. Clin Tech Small Anim Pract 2005, 20, 129–134, doi: 10.1053/j.ctsap.2004.12.018.
Open DOI Search in Google Scholar Back to article
Tîrziu A., Herman V., Imre K., Degi D.M., Boldea M., Florin V., Bochiș T.A., Adela M., Degi J.: Occurrence of Chlamydia spp. in conjunctival samples of stray cats in Timișoara municipality, western Romania. Microorganisms 2022, 10, 2187, doi: 10.3390/microorganisms10112187.
Open DOI Search in Google Scholar Back to article
Trifinopoulos J., Nguyen L.T., von Haeseler A., Minh B.Q.: W-IQ-TREE: a fast online phylogenetic tool for maximum likelihood analysis. Nucleic Acids Res 2016, 44, 232–235, doi: 10.1093/nar/gkw256.
Open DOI Search in Google Scholar Back to article
Ulbert Á.B., Juhász H., Karácsony Z., Bencze K., Deim Z., Burián K., Terhes G.: The occurrence of Chlamydia felis in cats and dogs in Hungary. Pathogens 2024, 13, 771, doi: 10.3390/pathogens13090771.
Open DOI Search in Google Scholar Back to article
Waskom W.L.: Seaborn: statistical data visualization. J Open Source Softw 2021, 6, 3021, doi: 10.21105/joss.03021.
Open DOI Search in Google Scholar Back to article
Yan C., Fukushi H., Matsudate H., Ishihara K., Yasuda K., Kitagawa H., Yamaguchi T., Hirai K.: Seroepidemiological investigation of feline chlamydiosis in cats and humans in Japan. Microbiol Immunol 2000, 44, 155–160, doi: 10.1111/j.1348- 0421.2000.tb02477.x.
Open DOI Search in Google Scholar Back to article
Zocevic A., Vorimore F., Vicari N., Gasparini J., Jacquin L., Sachse K., Magnino S., Laroucau K.: A real-time PCR assay for the detection of atypical strains of Chlamydiaceae from pigeons. PLoS One 2013, 8, e58741, doi: 10.1371/journal.pone.0058741.
Open DOI Search in Google Scholar Back to article