The other type is virulent (produces disease), is the cause of FIP, and is called feline infectious peritonitis virus (FIPV). It is believed that FIP occurs when FECV mutates to FIPV in the cat and starts to replicate in the cat's cells. What causes this mutation is unknown.he other type is virulent (produces disease), is the cause of FIP, and is called feline infectious peritonitis virus (FIPV). It is believed that FIP occurs when FECV mutates to FIPV in the cat and starts to replicate in the cat's cells. What causes this mutation is unknown.
How long does a typhoid shot last?   According to the CDC website, a booster dose is needed every 2 years for people who remain at risk.. The oral (live) vaccine lasts 5 years before another dose is neededâ¦.
Typhoid Vaccine: Injection. The typhoid injection is given only once, at least two weeks before travel. The injection lasts only two years compared with the five years of protection offered by the oral typhoid vaccine.After two years, a booster shot is needed for people who plan to continue traveling in countries where typhoid is common or who are otherwise at risk.he typhoid injection is given only once, at least two weeks before travel. The injection lasts only two years compared with the five years of protection offered by the oral typhoid vaccine.