General

Infected cat paw after declaw

Infected cat paw after declaw

Infected cat paw after declaw. Credit: Dr. Svetlana Kuznetsova, Ph.D., DVM

Svetlana Kuznetsova, DVM, an internationally renowned veterinary infectious disease specialist, is a professor and division director at the College of Veterinary Medicine at Virginia Tech. She joined the Virginia Tech faculty in 2000 after spending more than a decade at The Rockefeller University in New York. A graduate of the Moscow Institute of Veterinary Medicine, Kuznetsova received her doctorate at the Institute of Veterinary Medicine, Moscow, Russia.

Since then, Kuznetsova has been involved with multiple outbreaks of feline herpesvirus and calicivirus infections in cat populations and has worked with numerous cat and small animal veterinarians on the treatment and control of these diseases.

Kuznetsova is interested in the role of genetics and immunology in disease control, including the development of vaccines and the treatment of feline infectious peritonitis (FIP). She is a member of the Infectious Disease Specialty Group of the American College of Veterinary Internal Medicine (ACVIM). She is also a member of ACVIM's Veterinary Medical Data Analytics Group.

Here, she discusses the development of calicivirus vaccines.

What are caliciviruses?

Caliciviruses are non-enveloped, single-stranded, positive-sense RNA viruses. As the name implies, these viruses are related to the family Caliciviridae and are also closely related to other viruses such as noroviruses, hepatitis A, and some rotaviruses. Caliciviruses are the most common group of pathogens causing diarrhea in humans and animals. They cause gastrointestinal disease in both domestic and wild animals. Caliciviruses are a growing area of research in veterinary medicine.

What are calicivirus infections in cats?

Feline calicivirus (FCV) is the most commonly found calicivirus in cats. Feline enteric coronavirus (FECV) and feline respiratory coronavirus (FRCV) are also common caliciviruses in cats. Caliciviruses replicate in the gastrointestinal tract, producing intestinal disease, which may be severe and can cause morbidity and mortality in cats.

Diagnosis of calicivirus infections is typically done using immunofluorescence assays (IFA) to detect virus in cells or antigen detection tests. Virus neutralization is also used for diagnosis of some FCV infections. Serological tests for antibodies to caliciviruses are also avlable. A live FCV vaccine has been approved for use in cats. Other vaccines are in development for FCV and FRCV, but none are commercially avlable.

In addition to FCV, caliciviruses also cause disease in a number of species, including swine, cattle, dogs, rodents, and ruminants. Human caliciviruses include human enteric coronavirus (HECV) and human respiratory coronavirus (HCoV). The latter causes a mild upper respiratory infection and is the leading cause of viral pneumonia in the U.S. and the World Health Organization estimates that approximately 3-5 million cases of severe HCoV illness occur each year in the U.S.

What are calicivirus infections in dogs?

Dogs may also be infected with caliciviruses that cause gastroenteritis. Feline enteric calicivirus (FECV), canine distemper virus, and possibly other caliciviruses may cause diarrhea in dogs. Vaccination agnst canine distemper virus and other canine caliciviruses has been shown to help prevent disease. The use of vaccines agnst other canine caliciviruses has not been well studied in dogs.

Where is the world's research and development of calicivirus vaccines?

A number of calicivirus vaccines are in clinical development in the U.S., Europe and Asia. In the U.S. several companies are developing vaccines for HECV and the HCoV. In addition, a couple of companies have recently begun to manufacture vaccine based on the FCV virus (F9 vaccine). One of the leading development efforts is through the U.S. Military working with two separate companies, one a small U.S. company and the other an international company. While the U.S. Military is developing their own FCV vaccine, their intent is to provide it to all branches of the military. These efforts were announced in January 2010 and are in a Phase 1 clinical trial.

A number of other companies are also conducting Phase I and Phase II trials. Phase III trials are scheduled to begin in the fall of 2011. It is expected that the vaccines will be avlable for deployment to all members of the military by 2012.

A vaccine for HECV is expected to be in Phase III trials in Japan, but the timeline for that product is not yet known.

Why are there two types of vaccines?

There are currently two types of vaccines in development. One type is the currently avlable modified live vaccines (MLVs). These are based on the first natural canine calicivirus (FCV). They induce a strong immune response and are quite efficacious. However, they are based on the North American strn of FCV.

The other vaccine that is being developed (F9 vaccine) is a killed vaccine. The F9 vaccine contns whole killed virus. It is well tolerated and stimulates a strong immune response. Unfortunately, it is no more efficacious than the MLVs.

Which vaccine are we looking forward to the most?

Our mn interest is in the FCV vaccine (F9 vaccine). This vaccine has the potential to significantly decrease the number of illnesses and deaths associated with canine caliciviruses and has the potential to be extremely effective in the U.S. It may be the only vaccine that will allow effective protection for all populations at risk for exposure to canine caliciviruses.

The F9 vaccine is also important to the U.S. military because this is the only vaccine that can be administered in a low-risk vaccine program. It is possible to administer vaccines to a large population without risking infection.

What is our role?

As the scientific advisory board to the Defense Threat Reduction Agency, we are looking to develop the F9 vaccine for eventual use in military, veterinary and zoonotic medicine.

What is our role as members of the public?

As citizens we have a right to be involved in how our tax dollars are spent. Our membership on the scientific advisory board is one way that we can make sure our research is focused on the diseases that are most important