Feline Calicivirus Vaccination

Huang C, Hess J, Gill M et al.: A dual-strain feline calicivirus vaccine stimulates broader cross-neutralization antibodies than a single-strain vaccine and lessens clinical signs in vaccinated cats when challenged with a homologous feline calicivirus strain associated with virulent systemic disease, J Feline Med Surg 12:129, 2010.

Feline calicivirus (FCV) is generally associated with mild upper respiratory disease. In recent years, a more severe disease syndrome with high mortality has been linked to FCV infection. Viral mutations responsible for the different disease presentations have not been identified. In addition, these viruses differ in antigenicity, or how they appear to the immune system of the cat. This has an impact on the effectiveness of vaccines to induce protection against all strains of the virus. This report describes the ability of a vaccine containing two different strains of FCV to induce protection in vaccinated animals against many strains of the virus. The two strains used were a traditional FCV strain and a strain isolated from a case of virulent systemic disease (VSD). Serum from vaccinated cats was tested for protection (neutralization antibodies) against various FCV isolates. Immunity, as indicated by levels of serum neutralizing antibodies in vaccinated cats was tested against 37 European isolates of FCV as well as six VSD isolates from the United States. It is not clear as to whether these isolates were characterized genetically or antigenically; thus, their similarity or dissimilarity could not be assessed. This is important when assessing cross-protectiveness of a vaccine against different virus strains. Serum from cats vaccinated with both FCV strains neutralized more FCV isolates than that from cats vaccinated with a single FCV strain. Not surprisingly, cats vaccinated with the VSD-producing strain were protected against challenge with the same, virulent virus. The researchers conclude that this vaccine containing two strains is more effective than those containing a single strain. But given that the diversity of the strains against which the vaccine was tested was not described, this cannot be definitively stated. [MK]

Related articles:
Addie D, Poulet H, Golder MC et al.: Ability of antibodies to two new caliciviral vaccine strains to neutralise feline calicivirus isolates from the UK, Vet Rec 163:355, 2008.

Radford AD, Addie D, Belak S et al.: Feline calicivirus infection ABCD guidelines on prevention and management, J Feline Med Surg 11:556, 2009.

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Huang C, Hess J, Gill M et al.: A dual-strain feline calicivirus vaccine stimulates broader cross-neutralization antibodies than a single-strain vaccine and lessens clinical signs in vaccinated cats when challenged with a homologous feline calicivirus strain associated with virulent systemic disease, J Feline Med Surg 12:129, 2010.

Feline calicivirus (FCV) is generally associated with mild upper respiratory disease. In recent years, a more severe disease syndrome with high mortality has been linked to FCV infection. Viral mutations responsible for the different disease presentations have not been identified. In addition, these viruses differ in antigenicity, or how they appear to the immune system of the cat. This has an impact on the effectiveness of vaccines to induce protection against all strains of the virus. This report describes the ability of a vaccine containing two different strains of FCV to induce protection in vaccinated animals against many strains of the virus. The two strains used were a traditional FCV strain and a strain isolated from a case of virulent systemic disease (VSD). Serum from vaccinated cats was tested for protection (neutralization antibodies) against various FCV isolates. Immunity, as indicated by levels of serum neutralizing antibodies in vaccinated cats was tested against 37 European isolates of FCV as well as six VSD isolates from the United States. It is not clear as to whether these isolates were characterized genetically or antigenically; thus, their similarity or dissimilarity could not be assessed. This is important when assessing cross-protectiveness of a vaccine against different virus strains. Serum from cats vaccinated with both FCV strains neutralized more FCV isolates than that from cats vaccinated with a single FCV strain. Not surprisingly, cats vaccinated with the VSD-producing strain were protected against challenge with the same, virulent virus. The researchers conclude that this vaccine containing two strains is more effective than those containing a single strain. But given that the diversity of the strains against which the vaccine was tested was not described, this cannot be definitively stated. [MK]

Related articles:
Addie D, Poulet H, Golder MC et al.: Ability of antibodies to two new caliciviral vaccine strains to neutralise feline calicivirus isolates from the UK, Vet Rec 163:355, 2008.

Radford AD, Addie D, Belak S et al.: Feline calicivirus infection ABCD guidelines on prevention and management, J Feline Med Surg 11:556, 2009.

More on cat health: Winn Feline Foundation Library
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Virulent Systemic Feline Calicivirus

Reynolds BS, Poulet H, Pingret JL et al: A nosocomial outbreak of feline calicivirus associated virulent systemic disease in France, J Feline Med Surg 11:633, 2009.

This paper documents an outbreak of virulent systemic (VS) feline calicivirus (FCV) at a veterinary teaching hospital in France. The initial case was referred to the hospital, presenting with severe depression, fever, facial and limb edema, crusting, mucopurulent nasal discharge, oral ulceration and dyspnea. Within 10 days, 2 cats (one owned by a veterinary student and one that had visited the hospital 3 days previous) presented with similar disease symptoms. These 3 cats all died or were euthanized without a confirmed diagnosis. The fourth case presented 3 days after a visit to the hospital, and FCV was confirmed. At that point, the possibility of hospital-acquired infection was assessed, and 3 additional hospitalized cats were found to be infected. The hospital was then closed to cats for 19 days and disinfected. An eighth cat owned by a veterinary student who was working in the hospital during this period also contracted the virus and was hospitalized at a private clinic. Of the 8 affected cats, 3 died, 2 were euthanized, and 2 recovered. As indicated, 2 cases never in the affected hospital occurred in cats infected by their owners (veterinary students present at the hospital). The virus from this outbreak was characterized, and found to be the same in all cases. This outbreak illustrates the highly contagious nature of this virus. [MK]
>> PubMed Abstract

Related Articles:
Radford AD, Addie D, Belak S et al: Feline calicivirus infection. ABCD guidelines on prevention and management, J Feline Med Surg 11:556, 2009.
>> Free, full text article

Radford AD, Coyne KP, Dawson S et al: Feline calicivirus, Vet Res 38:319, 2007.
>> PubMed Abstract

More on cat health: Winn Feline Foundation Library
Join us on Facebook
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Reynolds BS, Poulet H, Pingret JL et al: A nosocomial outbreak of feline calicivirus associated virulent systemic disease in France, J Feline Med Surg 11:633, 2009.

This paper documents an outbreak of virulent systemic (VS) feline calicivirus (FCV) at a veterinary teaching hospital in France. The initial case was referred to the hospital, presenting with severe depression, fever, facial and limb edema, crusting, mucopurulent nasal discharge, oral ulceration and dyspnea. Within 10 days, 2 cats (one owned by a veterinary student and one that had visited the hospital 3 days previous) presented with similar disease symptoms. These 3 cats all died or were euthanized without a confirmed diagnosis. The fourth case presented 3 days after a visit to the hospital, and FCV was confirmed. At that point, the possibility of hospital-acquired infection was assessed, and 3 additional hospitalized cats were found to be infected. The hospital was then closed to cats for 19 days and disinfected. An eighth cat owned by a veterinary student who was working in the hospital during this period also contracted the virus and was hospitalized at a private clinic. Of the 8 affected cats, 3 died, 2 were euthanized, and 2 recovered. As indicated, 2 cases never in the affected hospital occurred in cats infected by their owners (veterinary students present at the hospital). The virus from this outbreak was characterized, and found to be the same in all cases. This outbreak illustrates the highly contagious nature of this virus. [MK]
>> PubMed Abstract

Related Articles:
Radford AD, Addie D, Belak S et al: Feline calicivirus infection. ABCD guidelines on prevention and management, J Feline Med Surg 11:556, 2009.
>> Free, full text article

Radford AD, Coyne KP, Dawson S et al: Feline calicivirus, Vet Res 38:319, 2007.
>> PubMed Abstract

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Feline Calicivirus and Fleas

Mencke, N., M. Vobis, et al. (2009). "Transmission of feline calicivirus via the cat flea (Ctenocephalides felis)." Parasitol Res 105(1): 185-9.

Feline calicivirus is an important and contagious pathogen of cats. It is often associated with respiratory disease that is most commonly mild and self-limiting. However, it may cause severe pneumonia, or rarely, a systemic lethal disease. Transmission occurs most commonly through direct and indirect contact between cats. This investigation examined the potential for fleas to spread the virus. Fleas were fed blood containing the virus, and their feces were collected. Infectious virus was found in the flea feces for more than a week after exposure, and the virus could be transmitted to susceptible kittens via the fleas. Thus fleas could be a potential source for spread of this virus. However, the level of virus artificially fed to the fleas in this experiment was very high. In addition, while inoculation of infected fleas via the nose and mouth in the kittens was effective in transmission, infestation of the kittens alone with the fleas was not efficient for virus transmission. The researchers conclude that fleas could potentially be a source for transmission of feline calicivirus and note that it emphasizes the importance of good flea control. However, spread by respiratory droplets and direct contact remains the most important modes of spread. Transmission via fleas would most likely be significant in situations of crowding and significant flea infestation. [MK]
>> PubMed Abstract

Related articles:
Radford, A. D., D. Addie, et al. (2009). "Feline calicivirus infection ABCD guidelines on prevention and management." J Feline Med Surg 11(7): 556-64.
>> PubMed Abstract

Hurley, K., P. Pesavento, et al. (2004). "An outbreak of virulent systemic feline calicivirus disease." J Amer Vet Med Assoc 224(2): 241-249.
>> PubMed Abstract

More on cat health: Winn Feline Foundation Library
Join us on Facebook

Mencke, N., M. Vobis, et al. (2009). "Transmission of feline calicivirus via the cat flea (Ctenocephalides felis)." Parasitol Res 105(1): 185-9.

Feline calicivirus is an important and contagious pathogen of cats. It is often associated with respiratory disease that is most commonly mild and self-limiting. However, it may cause severe pneumonia, or rarely, a systemic lethal disease. Transmission occurs most commonly through direct and indirect contact between cats. This investigation examined the potential for fleas to spread the virus. Fleas were fed blood containing the virus, and their feces were collected. Infectious virus was found in the flea feces for more than a week after exposure, and the virus could be transmitted to susceptible kittens via the fleas. Thus fleas could be a potential source for spread of this virus. However, the level of virus artificially fed to the fleas in this experiment was very high. In addition, while inoculation of infected fleas via the nose and mouth in the kittens was effective in transmission, infestation of the kittens alone with the fleas was not efficient for virus transmission. The researchers conclude that fleas could potentially be a source for transmission of feline calicivirus and note that it emphasizes the importance of good flea control. However, spread by respiratory droplets and direct contact remains the most important modes of spread. Transmission via fleas would most likely be significant in situations of crowding and significant flea infestation. [MK]
>> PubMed Abstract

Related articles:
Radford, A. D., D. Addie, et al. (2009). "Feline calicivirus infection ABCD guidelines on prevention and management." J Feline Med Surg 11(7): 556-64.
>> PubMed Abstract

Hurley, K., P. Pesavento, et al. (2004). "An outbreak of virulent systemic feline calicivirus disease." J Amer Vet Med Assoc 224(2): 241-249.
>> PubMed Abstract

More on cat health: Winn Feline Foundation Library
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New Antiviral Treatment for Feline Calicivirus

Smith, A. W., P. L. Iversen, et al. (2008). "Virus-specific antiviral treatment for controlling severe and fatal outbreaks of feline calicivirus infection." Am J Vet Res 69(1): 23-32.

During the past decade, several outbreaks of severe systemic disease associated with feline calicivirus (FCV) have occurred with high mortality in the affected animals. This study details evaluation of a virus-specific antiviral phosphorodiamidate morpholino oligomer (PMO) for treating 112 kittens involved in 3 natural outbreaks of disease in the United States. PMOs are molecules used to modify gene expression. This novel treatment modality has not previously been tested in cats. A calicivirus strain was isolated from a cat that died of natural hemorrhagic calicivirus disease and a PMO was synthesized. The PMO was administered on day 1 of clinical signs and continued for up to 7 days. Various antiviral doses were evaluated by comparing survival times, clinical recovery, and virus shedding. In the natural outbreaks, 47 of 59 treated cats survived, but only 3 of 31 untreated cats survived. PMO treatment reduced calicivirus shedding and improved clinical recovery. Virus-specific PMOs may be an effective modality for treatment of severe disease associated with feline calicivirus.
>> PubMed abstract

Related blog posts:
Virulent systemic calicivirus
Feline caliciviruses causing virulent systemic disease are genetically distinct


More on PMOs


More on cat health: Winn Feline Foundation Library

Smith, A. W., P. L. Iversen, et al. (2008). "Virus-specific antiviral treatment for controlling severe and fatal outbreaks of feline calicivirus infection." Am J Vet Res 69(1): 23-32.

During the past decade, several outbreaks of severe systemic disease associated with feline calicivirus (FCV) have occurred with high mortality in the affected animals. This study details evaluation of a virus-specific antiviral phosphorodiamidate morpholino oligomer (PMO) for treating 112 kittens involved in 3 natural outbreaks of disease in the United States. PMOs are molecules used to modify gene expression. This novel treatment modality has not previously been tested in cats. A calicivirus strain was isolated from a cat that died of natural hemorrhagic calicivirus disease and a PMO was synthesized. The PMO was administered on day 1 of clinical signs and continued for up to 7 days. Various antiviral doses were evaluated by comparing survival times, clinical recovery, and virus shedding. In the natural outbreaks, 47 of 59 treated cats survived, but only 3 of 31 untreated cats survived. PMO treatment reduced calicivirus shedding and improved clinical recovery. Virus-specific PMOs may be an effective modality for treatment of severe disease associated with feline calicivirus.
>> PubMed abstract

Related blog posts:
Virulent systemic calicivirus
Feline caliciviruses causing virulent systemic disease are genetically distinct


More on PMOs


More on cat health: Winn Feline Foundation Library

Read More