Prevalence Of Avian Influenza Virus Type A Antibodies In Khartoum State And Study Of Three Serodiagnosis Techiniques

Abstract

The objective of the study was to investigate the prevalence of AIV antibody Ab in Khartoum state, and Compare between serological tests; AGID, HI and ELISA. Two hundred and fifty eight blood samples were collected in 2006 from twelve farms in Khartoum state and subjected to serologic screening for type-specific antibodies to type A influenza viruses, there was serologic evidence of past infection with AI virus type A in some flocks. Agar gel immunodiffusion (AGID) and an enzyme-linked immunosorbent assay (ELISA) tests were used for detecting Ab against type A avian influenza (AI) virus. Hemagglutination-inhibition (HI) test was used for subtyping of the corresponding antigen. The sensitivity and specificity of the AI-ELISA was compared in the various groups with those of the AGID and the hemagglutination-inhibition (HI) test; prapered hyperimmune sera and field sera. During the course of preparation of hyperimmune sera (0-80 days) of specific-antibodies-negative (SAN) chickens with AI subtypes A/Mallard/Neth/12100 (H7N3) and Duck/Sing/645.3/97/128 (H5N1), the AGID test was able to detect type A specific Ab as early as 14 days postinoculation(PI). Similarly, the AI-ELISA detected AI Ab and measured rising levels of Ab through 66 days PI, at which time the chickens were re-exposed to AI virus at 21 days post primary inoculation with the same AI subtype. HI detected low levels of AI Ab at 14 days PI. Following a secondary infection, HI measured rising levels of AI-specific Abs (35-80 days PI).