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¦.
However, excessive inoculum of infection from food sources can overcome this immunity. Thus, typhoid can recur in future, either after years or if the infective dose in food is very high. The child does not need any typhoid vaccination for a period of about 2-3 years if he had confirmed typhoid fever. Rarely, some subjects can become carriers after antibiotic dose (for example cefixime); it is difficult to predict this possibility in an individual child.