Immunosuppressive effect of Cryptosporidium baileyi infection on vaccination against Newcastle disease in chicks.
Hemagglutination-inhibition titers (log2) to Newcastle disease (ND) virus were chronologically observed in chicks, which were orally inoculated with 5 x 10(5) oocysts of Cryptosporidium baileyi at 2 days of age and subsequently vaccinated with inactivated ND virus at 4 and 21 days postinoculation. In general, the titers were considerably lower in the infected chicks than those in the uninfected control throughout the experimental period (p < 0.01), and rapid negative seroconversions were observed in the infected chicks. The titers reached a peak on weeks 2 and 4 post-booster-vaccination in the control and infected chicks, respectively. Thus, C. baileyi infection was shown to have an immunosuppressive effect on ND vaccination when the agent was given to 2-day-old chicks. It is suggested that C. baileyi infection in chicks may increase the host susceptibility to ND virus.
Rhee
J K
JK
Bio-Safety Research Institute, Chonbuk National University, Chonju, Korea.
Kim
H C
HC
Lee
S B
SB
Yook
S Y
SY
D000818:Animals; D002645:Chickens; D003457:Cryptosporidiosis / Q000276:immunology*; D003458:Cryptosporidium / Q000276:immunology*; D006385:Hemagglutination Inhibition Tests; D007165:Immunosuppression Therapy; D008297:Male; D009521:Newcastle Disease / Q000276:immunology*; D009522:Newcastle disease virus / Q000276:immunology*; D014765:Viral Vaccines / Q000276:immunology*
D014765:Viral Vaccines