Cytopathic astrovirus isolated from porcine acute gastroenteritis in an established cell line derived from porcine embryonic kidney

Abstract

A cytopathic astrovirus was isolated from pigs with acute diarrhea in an established cell line that was derived from porcine embryonic kidneys with the aid of trypsin. The virus showed a distinct cytopathic effect characterized by an enlargement of cells and the appearance of fine granules in the cytoplasm. Porcine astrovirus was shown to have an RNA genome, as determined by the effect of 5-iodo-2'-deoxyuridine on its replication, and five polypeptides with molecular masses of 13,000, 30,000, 31,000, 36,000, and 39,000 daltons; and it was shown to be stable to lipid solvents and heating at 50 degrees C for 30 min but somewhat labile to acid (pH 3.0). The buoyant density of the isolate determined in CsCl was 1.35 g/ml. Seroconversion to the virus was evident in the paired serum specimens obtained from pigs with diarrhea that were housed at the farm where the disease occurred. The neutralization test on serum specimens collected randomly from 128 adult pigs of eight herds revealed that 50 of the serum specimens were positive for antibody to porcine astrovirus, although there was considerable variation in the prevalence among herds, ranging from 0 to 83%. Hysterectomy-produced, colostrum-deprived, 4-day-old pigs developed mild diarrhea after oral exposure to porcine astrovirus propagated in the cell culture; and the virus was isolated again from diarrheal stool specimens.

Molecular investigations on the prevalence and viral load of enteric viruses in pigs from five European countries

“…Despite high prevalence, there has been no strong evidence that PAstV can cause enteric disease associated with clinical signs. Only an oral infection of 4 day-old piglets with a cell culture grown PAstV1 resulted in mild diarrhea (Shimizu et al, 1990).…”

Astrovirus infections in humans and animals – Molecular biology, genetic diversity, and interspecies transmissions

“…Although PoAstV is described as a common finding from fecal samples of apparently healthy pigs (Luo et al, 2011;Reuter et al, 2011), the clinical significance of this infection has not been completely clarified. As a matter of fact, clinical symptoms have been reported mainly in piglets, often in association with rotavirus-, coronavirus-and calicivirus-like infections (Bridger, 1980;Indik et al, 2006;Luo et al, 2011;Shimizu et al, 1990;Shirai et al, 1985). PoAstV prevalence is considered variable from 0% to 83% and 100% based on serological and virological surveillance, respectively (Luo et al, 2011;Shimizu et al, 1990).…”

“…As a matter of fact, clinical symptoms have been reported mainly in piglets, often in association with rotavirus-, coronavirus-and calicivirus-like infections (Bridger, 1980;Indik et al, 2006;Luo et al, 2011;Shimizu et al, 1990;Shirai et al, 1985). PoAstV prevalence is considered variable from 0% to 83% and 100% based on serological and virological surveillance, respectively (Luo et al, 2011;Shimizu et al, 1990). Though ICTV officially recognizes only one species of PoAstV (PoAstV-1) several reports have demonstrated the existence of multiple serotypes and subtypes.…”

“…At least two serotypes have been reported to date (Frazier et al, 1990;Imada et al, 1980;Pantin-Jackwood et al, 2011;Shirai et al, 1991). ANV typically causes histological changes in the kidneys although the viral antigen can be detected in other organs, namely liver, spleen, pancreas, jejunum and rectum (Imada et al, , 1983Shimizu et al, 1990;Shirai et al, 1989Shirai et al, , 1992. Young chicks are the most susceptible and become resistant to disease after the first month of life (Imada et al, 1981).…”

Development of an RT-PCR diagnostic test for an avian astrovirus

“…Fluorescent antibody tests may fail to recognize astroviruses of different serotypes (Matsui and Greenberg, 1996). Furthermore, virus isolation by cell culture is limited to bovine, feline, porcine, and human astroviruses (Lee and Kurtz, 1981;Woode et al, 1984;Harbour et al, 1987;Shimizu et al, 1990).…”