Astrovirus Induces Diarrhea in Turkey Poults via Sodium Malabsorption

We studied a model of turkey astrovirus type 2 (TAstV‐2)‐induced diarrhea in poults. Four days post‐infection, when infected poults exhibited diarrhea, either intact or stripped intestinal mucosa was mounted on Ussing chambers to study ion transport. Isotopic flux studies demonstrated impaired Na + absorption with reduced short circuit current and increased conductance in astrovirus‐infected jejunum. In electron microscopic examinations, the terminal web region displayed frequent dense aggregations in TAstV‐2 infected intestine. Rearrangement of apical F‐actin was evident on immunofluorescence as thick, dense aggregations in TAstV‐2‐infected intestine. Although the total protein expression for the major apical membrane Sodium Hydrogen Exchanger, NHE3, was not changed in western analyses of astrovirus‐infected jejunum, a significant shift was observed for expression of NHE3 from detergent insoluble fractions to detergent soluble fractions of TAstV‐2 infected jejunum. Alternatively, total expression of NHE2 was up regulated in infected jejunum. Taken together, astrovirus TAstV‐2 induces malabsorptive diarrhea associated with actin re‐arrangement and redistribution of apical membrane NHE3. Further studies are currently being conducted to identify the electrogenic component of Na+ malabsorption.