Cranbourne trainer Doug Harrison is hoping to strike while the iron is hot with Alrouz at Sandown.

The rising 10-year-old gave Harrison his first winner for 2017 when successful at Sandown last week and lines up again on Wednesday over 1800 metres in the Ladbrokes Up For The Challenge.

Harrison has saddled only 13 runners this year after a virus swept through his stable severely affecting his younger brigade of horses.

"We've had a thing with congestion or fluid on the lungs with a few of the three-year-olds," Harrison said.

"It's been very frustrating as it keeps coming back just when you think they're over it.

"There's been a few other niggly things also that keep happening and you wonder what you've done wrong."

Harrison decided on a change of training routine for Alrouz before his success at Sandown last week when the gelding was backed from $61 to $21 before his 1600m win.

The trainer suggested it was one of Alrouz's better career victories which came at his first start since January.

"He's been a bit of a cranky old fella so he's been doing a lot of swimming and working through the sand tracks out the back at Cranbourne," Harrison said.

"Generally he works around here (home) but he gets the idea of getting his head up and taking off and ends up cutting his mouth a little bit.

"He enjoyed the different work but to get a guide we put him in an 800 metre trial in which he trialled very well for a horse getting over a little bit of ground."

Harrison has kept Alrouz to a similar training regime since last week.

"He's a naturally clean-winded horse and does go well fresh," Harrison said.

"It's a matter of whether he backs up and can keep going."

Apprentice Boris Thornton takes over from Ethan Brown after the latter was suspended for his winning ride last week.

Stablemate Valrouz, the younger sister of Alrouz, makes her return in the Elaren Security Services Handicap.