Feline infectious peritonitis (FIP) is a fatal, incurable disease that affects cats.It is caused by Feline Infectious Peritonitis Virus (FIPV), which is a mutation of Feline Enteric Coronavirus (FECV) - (Feline coronavirus FCoV).Experts do not agree on the specifics of genetic changes that produce the FIPV.t is caused by Feline Infectious Peritonitis Virus (FIPV), which is a mutation of Feline Enteric Coronavirus (FECV) - (Feline coronavirus FCoV).
Some people get mild cases of only a few days, o â¦ thers get severe cases of a few weeks or more and are hospitalized. On average, the symptoms of the flu generally last 3 - 10 days but the H1N1/09 virus lasts more typically 4 - 7, although a cough and fatigue may persist for up to 2 weeks.
âIn general, cold/flu symptoms may last for about a week to ten days,â Margarita Rohr, MD, clinical instructor of internal medicine at NYU Langone Health, tells Health. âAnd you are most contagious one day prior to the start of symptoms until five to seven days after symptoms start.