Tom Dumoulin hopes his early-season illness is behind him, announcing on social media that he is being treated for intestinal parasites and already feeling better.

Dumoulin, who has not raced since dropping out of the Critérium du Dauphiné last season due to his knee injury from a crash in the Giro d'Italia, was due to being his season at the Volta a la Comunitat Valenciana this month but before the race began he dropped out due to illness.

Last week he announced he would have to miss Tirreno-Adriatico and Milan-San Remo because the illness prevented him from attending a planned altitude camp.

Jumbo-Visma ordered a battery of tests, ruling out the Epstein-Barr virus which has heavily impacted the seasons of riders like Mark Cavendish, Esteban Chaves and Beñat Intxausti - who recently retired because of the disease.

According to the team, Dumoulin had been suffering from intestinal upset and low energy.

"As you all know, I had not been feeling well recently," Dumoulin wrote on Instagram. "Last week, we found parasites in my gut and since then I started medication. I am feeling much better as I have had good training sessions today and over the weekend. I’m looking forward to planning my season start and next goals very soon! I’ll keep you posted!"

Dumoulin is due to share Tour de France leadership duties on Jumbo-Visma's team with Primoz Roglic and Steven Kruijswijk.

Other professional cyclists have suffered from parasitic infections including four-time Tour de France winner Chris Froome, who attributed being cured of bilharzia with his sudden rise to form. Jeremy Roy, Fabio Felline, Igor Astarloa and Romain Feillu were once sidelined with toxoplasmosis. Former Tour winner Laurent Fignon suffered from a tapeworm.

Neither Dumoulin nor his team identified the parasite for which he was treated.