FCV Transmission and Persistence in Multicat Environments

A cat may recover from the obvious signs of feline calicivirus (FCV) infection and still remain relevant to transmission within a multicat environment. This is one reason FCV can be particularly difficult to control in shelters, colonies, and larger households. 

The challenge is not limited to direct contact between sick cats. Viral shedding can continue for prolonged periods, while contaminated surfaces, equipment, and personnel can contribute to spread. 

Shedding Can Continue After Clinical Recovery 

During acute infection, FCV is shed mainly through oral and nasal secretions, although virus can also be detected in blood, urine and faeces. Many cats continue shedding for at least 30 days, while some may shed for years or even lifelong^[1]. 

This prolonged shedding has important implications in multicat settings. A cat that no longer appears clinically affected may still contribute to transmission. 

The difference in prevalence between household sizes illustrates the challenge. FCV prevalence was reported as 2.5% in healthy household groups containing fewer than four cats, compared with 32% in households with four or more cats^[1],[2]. In shelters and colonies, reported prevalence ranges from 50–90%^[3]. 

How Does FCV Move Through a Facility?^[3] 

Direct transmission occurs through infected secretions. However, FCV can also persist in the environment and be transferred indirectly. 

The virus can survive for up to one month on dry surfaces at room temperature, with longer survival under colder conditions. Persistence may be longer in damp environments, and aerosol spread has also been detected in facilities. 

Potential indirect routes include: 

• Cages and other contaminated surfaces 
• Feeding and cleaning equipment 
• Personnel and fomites 
• Contaminated hands 

During one outbreak, the hands of a single caregiver were considered capable of infecting as many as 10 cats^[4]. 

Flea-associated transmission has also been demonstrated experimentally, with infectious virus detected in flea faeces for up to eight days^[3]. 

Why Multicat Settings are Especially Difficult 

Shelters and colonies combine several factors that favour ongoing FCV circulation. High cat turnover is associated with greater viral genetic variability, whereas stable multicat households show lower diversity. 

High prevalence in colonies is also associated with greater strain diversity, potentially reflecting persistent infection and reinfection. 

This makes infection control more than simply separating visibly sick cats. Reducing opportunities for transmission throughout the environment matters. 

Good hygiene and biosecurity may reduce FCV spread. In settings where cats, personnel, equipment, and contaminated surfaces repeatedly interact, these measures become particularly relevant. 

Clinical Bottom Line 

FCV control in multicat environments is complicated by prolonged shedding, environmental persistence and multiple transmission routes. Cats may continue shedding for months or considerably longer after acute disease, while contaminated hands, equipment, surfaces and other fomites can facilitate indirect spread. High turnover and persistent infection can also contribute to greater strain diversity. For shelters, colonies, and larger households, consistent hygiene and biosecurity are therefore important components of reducing FCV transmission.

Reviews & Comments

References:

1. Berger A, Willi B, Meli ML, Boretti FS, Hartnack S, Dreyfus A, Lutz H, Hofmann-Lehmann R. Feline calicivirus and other respiratory pathogens in cats with Feline calicivirus-related symptoms and in clinically healthy cats in Switzerland. BMC veterinary research. 2015 Nov 13;11(1):282. https://link.springer.com/content/pdf/10.1186/s12917-015-0595-2.pdf
2. Kratzer G, Lewis FI, Willi B, Meli ML, Boretti FS, Hofmann-Lehmann R, Torgerson P, Furrer R, Hartnack S. Bayesian network modeling applied to feline calicivirus infection among cats in Switzerland. Frontiers in veterinary science. 2020 Feb 26;7:73. https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2020.00073/pdf
3. Hofmann-Lehmann R, Hosie MJ, Hartmann K, Egberink H, Truyen U, Tasker S, Belák S, Boucraut-Baralon C, Frymus T, Lloret A, Marsilio F. Calicivirus infection in cats. Viruses. 2022 Apr 29;14(5):937. https://www.mdpi.com/1999-4915/14/5/937
4. Deschamps JY, Topie E, Roux F. Nosocomial feline calicivirus-associated virulent systemic disease in a veterinary emergency and critical care unit in France. Journal of Feline Medicine and Surgery Open Reports. 2015 Dec 15;1(2):2055116915621581. https://journals.sagepub.com/doi/pdf/10.1177/2055116915621581