Christian Kabasele joked Watford are "injecting" Covid-19 into players and staff members in a sarcastic response to the club being accused of trying to avoid relegation.
Watford spent much of the Premier League season in the bottom three but sat 17th when the coronavirus pandemic resulted in the suspension of play in England's top-flight in March.
Adrian Mariappa confirmed he was one of three people from the Hornets – and six across the Premier League – to test positive for the virus in the first round of analysis conducted by clubs last Sunday and Monday.