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¦.
Live Typhoid Vaccine (Oral). 1  Should not be given to children younger than 6 years of age. 2  Four doses, given 2 days apart, are needed for protection. 3  The last dose should be given at least 1 week before travel to allow the vaccine time to work.4  A booster dose is needed every 5 years for people who remain at risk.ive Typhoid Vaccine (Oral). 1  Should not be given to children younger than 6 years of age. 2  Four doses, given 2 days apart, are needed for protection. 3  A booster dose is needed every 5 years for people who remain at risk.