Isolation of reovirus type 3 from foals.

This research investigates the isolation of Reovirus type 3 from both healthy and sick foals. Five healthy foals and one foal with peritonitis were found to have the virus present in their fecal matter or lymph nodes.

Background

• Reoviruses are common in many vertebrates and are often associated with respiratory illnesses. This research specifically focuses on the presence of reovirus type 3 in young horses, known as foals.
• In the past, other types of reoviruses have been isolated from both healthy and sick horses and are believed to be a common cause of respiratory disease in horses.
• Research has indicated that all three serotypes of reoviruses are prevalent among equines in many countries.

Methodology

• Specimens were collected from foals on breeding farms in Hokkaido, with a total of 66 fecal samples and 2 lymph node samples taken from both healthy and sick foals ranging from 1 week to 4 months old.
• The samples were processed and then inoculated into three types of cell cultures: RK-13, MA-104, and Vero cells.
• If no cytopathic effect (CPE) was seen in the cell cultures, further three blind passages were performed.
• Three strains of reovirus were used as reference during this study: the Lang strain of reovirus type 1, the Jones strain of reovirus type 2, and the Abney strain of reovirus type 3. Antisera against these strains were created to help identify the isolated virus.

Findings

• The virus was successfully isolated from 5 out of the 66 fecal specimens and one of the lymph node specimens.
• The fecal specimens showed a variety in the cell cultures in which the virus was detectable. One sample yielded virus in all three cell culture types, while three only yielded virus in the RK-13 cell cultures and one only in the MA-104 cell cultures.
• Each identified strain was given a unique name, and the CPE was observed in the 2nd to 4th passages of the virus regularly.

The research is of importance for further studies into the relationship between reovirus type 3 and respiratory disease in horses, as well as its prevalence in equine populations.