The immunity is hypothesized to have to do with the method used by the HIV viruses, or by several bacteria, and yet other viruses, to infect the host cell.
Smallpox, black plague, HIV and cholera, among others, use the same or very similar, pathway. I know that I am naturally immune to cholera but I'm not going to do an experiment to see if I am immune to HIV, or smallpox!
61 posted on 02/22/2004 5:57:06 PM PST by muawiyah
Several studies (reviewed by Glass et al., 1985) indicated that individuals with blood group O are at higher risk of contracting cholera (due to Vibrio cholerae 01) than those with other blood groups and that individuals with blood group AB are relatively resistant to cholera. Clemens et al. (1989) demonstrated that individuals with blood group O are at higher risk for cholera due to only the E1 Tor biotype of V. cholerae 01. During a large field trial in Bangladesh of killed oral cholera vaccine, persons with blood group O were significantly less protected against severe cholera than were persons with AB blood group. Faruque et al. (1994) found that patients in Bangladesh who had diarrhea due to V. cholerae 0139 were nearly twice as likely as controls to be of blood group O (64 vs 34%) and that individuals with blood group AB were at no risk for diarrhea due to V. cholerae 0139. Individuals with blood group O were the most susceptible to diarrhea due to V. cholerae 0139, followed in order by groups B, A, and AB.
75 posted on 02/23/2004 2:02:21 PM PST by AdmSmith