Detection of antibodies against Turkey astrovirus in humans

Abstract

Astroviruses are a leading cause of gastroenteritis in mammals and birds worldwide. Although historically thought to be species-specific, increasing evidence suggests that astroviruses may cross species barriers. In this report, we used enzyme-linked immunosorbent assays to screen sera from three distinct human cohorts involved in influenza studies in Memphis, TN or Chapel Hill, NC, and Midwestern poultry abattoir workers for antibodies to turkey astrovirus type 2 (TAstV-2). Surprisingly, 26% of one cohort's population was TAstV-2 positive as compared to 0 and 8.9% in the other cohorts. This cohort was composed of people with exposure to turkeys in the Midwestern United States including abattoir workers, turkey growers, and non-occupationally exposed participants. The odds of testing positive for antibodies against turkey astrovirus among abattoir workers were approximately 3 times higher than the other groups. These studies suggest that people with contact to turkeys can develop serological responses to turkey astrovirus. Further work is needed to determine if these exposures result in virus replication and/or clinical disease.

Figure 1. Development of a competitive astrovirus ELISA.

A) Rabbit anti-HAstV-1 or TAstV-2 polyclonal antibodies were pre-incubated with PBS (no treatment) or purified recombinant HAstV-1 or TAstV-2 capsid proteins then tested for binding to bound HAstV-1 or TAstV-2 capsid protein by ELISA. *p<0.05. B) Specificity of the rabbit polyclonal antibodies. Samples were run in at least duplicate and data are shown as mean values. Error bars indicate SD.

Figure 2. Specificity of the human sera to HAstV-1 and TAstV-2 capsid proteins.

A) HAstV-1 positive sera were pre-incubated with PBS (no treatment) or HAstV-1 or TAstV-2 capsid proteins and binding to HAstV-1 capsid protein assessed by ELISA. B) TAstV-2 positive sera were pre-incubated with PBS (no treatment) or HAstV-1 or TAstV-2 capsid proteins and binding to TAstV-2 capsid protein assessed by ELISA. C) TAstV-2 positive and negative sera were pre-incubated with PBS (no treatment) or chicken astrovirus and binding to TAstV-2 capsid protein assessed by ELISA. A plus sign denotes serum sample was positive for indicated virus, and a minus sign denotes serum sample was negative for the indicated virus. Samples were tested in duplicate and data shown are mean values; error bars indicate SD. *p<0.05.