Fcv virus in cats

There were no cats with a pre-vaccination antibody titer, an increase in titer by Day 7, and a decrease by Day 28 Group 6. The numbers of cats at each time point are given in Section 2. Study protocol. Median titers: Day 0, 20; Day 7, 80; Day 28, Median titers: Day 0, 80; Day 7, 80; Day 28, Figure 2 shows the antibody responses of the cats. There were no cats with a pre-vaccination antibody titer and no subsequent increase in titer Group 5.

Median titers: Day 0, ; Day 7, ; Day 28, Feline calicivirus isolate KS20 used in VN was shown to have cross-reactivity with sera from cats originating from the same geographical region as the cats in the present study and was therefore chosen [ 18 ]. Virus neutralization was performed in this study because it detects antibodies that neutralize infectious particles and thus prevent infection [ 15 ]; however, VN is thought to be less sensitive than ELISA because the results are strongly influenced by the degree of antigenic relationship between the isolate used in the test and the isolate obtained from previously vaccinated or infected cats.

ELISA was used in addition to VN because it has been shown to have a broad spectrum and detects antibodies produced after vaccination with the G1 and vaccine strains [ 14 ], which are commonly used for FCV vaccination in Germany. Comparison of VN and ELISA results was of particular interest in relation to the response to vaccination because the cats were vaccinated with a vaccine containing strains G1 and Virus neutralization had fewer positive results after vaccination than ELISA, suggesting that VN does not always detect antibodies against vaccine strains G1 and [ 9 ].

Prevalence of pre-vaccination antibodies was A study in France showed that In Brazil, An association between prevalence of antibodies and the previous vaccination regime was likely in the above-mentioned studies but statistical analysis was not performed. A study of cats taken into an animal shelter in Florida found that cats older than six months OR: One aim of the present study was to evaluate the association of possible factors with the presence of pre-vaccination antibody titers.

The association between presence of VN antibodies and vaccination status vaccinated or not vaccinated previously was an interesting finding and was also seen in cats tested for antibodies against feline panleukopenia after MLV vaccination [ 21 ]. The factor time since last vaccination was not associated with the occurrence of pre-vaccination VN antibodies.

This is in agreement with the results of a study by Mouzin and coworkers , in which the geometric mean of the titer against FCV after MLV vaccination did not decrease when time since last vaccination increased [ 22 ]. However, time since last vaccination was correlated with the presence of ELISA antibodies in the present study and cats that had been vaccinated within the last 1—3 years were more likely to have pre-vaccination antibodies than cats that had not been vaccinated. The type of vaccine can also affect the antibody response, and MLV vaccines are known to elicit strong and long-lasting antibody responses [ 23 ].

Multivariate analysis did not identify any environmental factors that had significant associations with the prevalence of antibodies. Another study also failed to detect an association between environmental factors and presence of FCV antibodies [ 22 ].

Older cats are more likely to have been exposed to the virus and are therefore more likely to have antibodies against FCV [ 24 ]. An increase in VN antibody titer after vaccination was seen in only Another possibility is that neutralizing antibodies occurred only after the day study period.

It is possible that these cats developed a cellular response in the absence of a humoral response. Protection against FCV in the absence of neutralizing antibodies 1—4 weeks after vaccination has been reported in experimental challenge studies [ 9 , 26 ].

A non-response to vaccination might occur because the immune system fails to recognize the vaccine antigen [ 27 ]. Other reasons for a poor response to vaccination including concurrent and chronic disease, immunosuppression, and faulty vaccine administration and storage were ruled out. This could be explained by an incidental natural infection with a strain not cross-reactive with strains G1 and This could have been the result of binding of pre-existing antibodies to the vaccine virus.

Examination of the course of antibody titer in these cats would require a longer study period than the day period used. There are no studies so far evaluating antibody response in cats with different pre-vaccination antibody titers. Outdoor cats are more likely to have been exposed to FCV, and memory cells generated during the primary vaccination response tend to be more effective at producing antibodies in response to re-vaccination or field-virus re-exposure [ 23 ].

Interestingly, the pre-vaccination antibody titer was not associated with an increase in titer after vaccination. It has been proposed that high antibody levels neutralize the vaccine virus before it stimulates the immune system, which has been shown in FPV vaccination [ 28 ]; however, this cannot be confirmed for FCV based on the results of the present study.

Many veterinarians today choose to measure parvovirus antibody titers to determine whether adult cats and dogs require re-vaccination [ 28 , 29 , 30 ]. It can be useful for determining whether vaccination is required at the time of an individual health care assessment, although the benefit of measuring FCV antibodies before vaccination is still discussed controversially.

In addition, and even more importantly, the value of measuring FCV antibodies to predict protection is generally limited as antibodies detected in a cat do not necessarily protect against the strains in the field [ 1 ]. One limitation of the study was the small amount of available serum especially for ELISA , which meant that FCV antibodies could not be determined in all cats.

In addition, it should be noted that a lack of an increase in antibody titer is not equivalent to a lack of protection against disease as cell-mediated immunity can also be an effective mode of protection [ 23 ]. The vaccine used in the present study has been shown to provide protection against challenge even in the absence of detectable neutralizing antibodies [ 9 ].

Many cats had pre-vaccination antibodies against FCV even those that had been vaccinated more than one year before the start of the study. The prevalence of antibodies depended on the vaccination history and age of the cats. Considering the results of the present study and the fact that different FCV strains circulate in the cat population, measuring the presence of FCV antibodies cannot replace routine vaccination against FCV in cats.

We thank Boehringer for partially supporting this study and especially Jean-Christophe Thibault and Florian Seckerdieck for their valuable input.

Conceptualization K. A part of the study was funded by Boehringer Ingelheim. Boehringer Ingelheim played no role in the collection and interpretation of data, or in the decision to submit the manuscript for publication. There is no commercial conflict of interest as the information generated here is solely for scientific dissemination. The authors declare that they have no competing interests. National Center for Biotechnology Information , U.

Journal List Viruses v. Published online Jul Author information Article notes Copyright and License information Disclaimer. Received Jul 22; Accepted Jul This article has been cited by other articles in PMC.

Abstract This study evaluated the prevalence of feline calicivirus FCV antibodies and response to vaccination in healthy adult cats. Keywords: FCV, protection, immunization, antibody titer. Introduction Infection with feline calicivirus FCV is common in cats and can result in acute oral and upper respiratory tract disease [ 1 ]. Materials and Methods 2. Study Population Serum samples from cats were included in this prospective study. Table 1 Characteristics of cats and association with presence of pre-vaccination VN antibodies and ELISA antibodies to feline calicivirus in uni- and multivariate analysis.

Open in a separate window. Study Protocol On Day 0, each cat received a single dose of a vaccine containing inactivated FCV antigen strains G1 and with at least 2. Most cats develop an upper respiratory tract infection and in more severe cases, the virus travels into the lungs where it causes pneumonia. At first the cat will have symptoms that look like a cold, with sneezing, nasal congestion, fever and sometimes drooling. Large amounts of discharge can come from the eyes and nose.

In more severe cases, cats can also develop inflammation and ulcers on the tongue, and the lining of the mouth. Lethargy, mild lameness and lack of appetite may also occur. These symptoms can persist from five to 10 days in mild cases and up to six weeks in more severe ones. During the course of the illness, opportunistic bacterial infections can also occur. Cats may lose weight, and the infection can also cause abortions in pregnant cats.

Most cats recover completely, but some will go on to develop a chronic form of gingivitis that causes thick and inflamed gums, which makes eating painful. Elderly cats and young kittens are more likely to suffer more severe symptoms. Fortunately, it is quite rare for cats to succumb to FCV infection. Cats that develop FCV-VSD will have much more severe symptoms, including a high fever, swelling of the head and legs, as well as crusting sores and hair loss on the nose, eyes, ears and footpads.

The mouth and ears may turn yellowish from liver damage, and there may be bleeding under the skin and in the gastrointestinal tract. Pet owners should always bring their cat to see the veterinarian if it shows signs of respiratory disease.

FCV causes about half of the respiratory infections that occur in cats, but feline alphaherpesvirus1 sometimes called feline rhinotracheitis virus is another common cause and sometimes dual infections occur.

The bacterial species Chlamydia felis and Mycoplasma felis also cause respiratory disease, and may complicate FCV infections.

A veterinarian will examine the cat for symptoms. In most cases, there is no need to make a definite diagnosis, as these infections are common and will resolve with supportive treatment. However, if multiple cats are infected or the cats are housed with others, the veterinarian may take swabs from the eyes, nose or mouth. These swabs will be sent to the lab to test for the presence of the virus. Labs can also test tissue or serum samples. Commercial labs detect the presence of FCV in two ways: by growing the virus in cells in a petri dish, or through reverse transcriptase PCR RT-PCR , a procedure that detects a segment of genetic material that is specific to calicivirus.

Both tests are equally effective, though the RT-PCR test may be more common in some areas, as part of a panel that tests for several organisms that cause respiratory disease. Test results should be interpreted carefully.

Many cats that appear healthy, especially ones recently adopted from a shelter, pet store or breeder, will test positive for the virus due to previous exposure, so a positive result does not necessarily indicate that FCV is the cause of the problem. Recent vaccination with a modified live strain of the virus can also cause a false positive result.

Incorrect negative results are more likely if the cat is swabbed more than a week after the start of the infection.

Currently there is no treatment to stop the virus, but pet owners can offer supportive care for their cat while its immune system fights the infection. Most cats can recover at home, but severely affected cats may need intensive nursing care. Keep the nose and eyes of the cat clean and use vaporizers and saline nose drops to help clear the nasal passages. The circumstances and disease signs were very similar to those recently described in an outbreak of FCV hemorrhagic disease in Northern California Vet.

The virus entered the facility through shelter cats showing upper respiratory signs. Affected cats manifested high fever, anorexia, labored respirations, oral ulceration, facial and limb edema, icterus, and pancreatitis.