This case illustrates several issues: 1) domestic animals such as cats (3), dogs (3,4), and rabbits (9) may serve as reservoirs for EHEC, irrespective of whether they are the primary or secondary source for these bacteria; 2) domestic cats as carriers may excrete EHEC for a prolonged period; 3) autovaccination may be effective for treating EHEC-infected animals; and 4) fondness for pets may be problematic: although EHEC O145:H--is among the 4 most often isolated EHEC serotypes associated with severe colitis or life-threatening hemolytic uremic syndrome (10), the girl's parents, after weighing the infectious risks against the psychological benefits for both their daughter and her feline companion, decided not to send the cat to an animal shelter until its EHEC infection disappeared.
Clinical picture and isolation of EHEC serotype 0145:H-from stool samples of child and her cat * Date Girl Cat Dec 1, 2004 Vomiting and diarrhea Dec 9 Tested positive ND Dec 22 Tested positive Tested positive Dec 28 Tested positive ND Jan 10, 2005 Tested positive ND Jan 17 Tested positive ND Jan 21 Tested negative ND Jan 24 Tested positive Tested positive, treated with probiotics Feb 1 Tested positive ND Mar 4 Tested negative ND Mar 12 Tested negative ND Apr 25 ND Tested positive Jun 25-Jul 4 ND Autovaccination Jul 29 ND Tested negative Aug 11 ND Tested negative * EHEC, enterohemorrhagic Escherichia coli; positive and negative refer to the isolation of EHEC serotype O145:H-; ND, no testing was done.
* Bernard Hirschel declares the autovaccination
hypothesis to be dead (RITA!
Reasons behind studying treatment interruptions have varied from "autovaccination
" (the hypothesis that alternately starting and stopping HAART might enhance immune responses to HIV) to minimizing drug toxicities and side effects.
Second, many studies have explored the concept of "autovaccination" or "autoimmunization" in conjunction with treatment interruption.
The benefits of STIs, including the potential to induce autovaccination, have been studied extensively in patients chronically infected with HIV.
Such "autovaccination" would be followed by withdrawal of HAART.
These results provide strong arguments against the hypothesis that "autovaccination" helps to improve immune control of HIV.
However, most research in patients with chronic HIV disease suggests that such immune stimulation or "autovaccination
" is not a successful strategy for treating HIV.