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  Four doses: one capsule every other day for a week (day 1, day 3, day 5, and day 7). The last dose should be given at least 1 week before travel to allow the vaccine time to work.  Swallow each dose about an hour before a meal with a cold or lukewarm drink. Do not chew the capsule.