Intestinal fortitude has become a prized commodity at Indian Wells where Vera Zvonareva and Gael Monfils are among eight players who have succumbed to a widespread viral infection.

Russian Zvonareva, the ninth seed in the WTA tournament, withdrew from her scheduled third-round match on Sunday, gifting Czech Klara Zakopalova a spot in the next round.
Earlier in the day, Frenchman Monfils, the 14th seed in the ATP event, American Vania King and Austrian Juergen Melzer also pulled out because of stomach problems.

"I'm really sorry to withdraw from the tournament but unfortunately I'm not feeling well enough to compete today," Zvonareva, a 12-time winner on the WTA Tour, said in a statement.

"Hopefully I can recover from the illness and play in the next event (in Miami) but today I just don't feel that I can go out there and perform well enough."

Monfils, who had been set to play his first match against Russian Nikolay Davydenko in the second round, was replaced by lucky loser Bjorn Phau of Germany.

King, who had never reached the fourth round at Indian Wells, tweeted on Sunday: "Just spent one of the worst nights of my life (gruesome details) fever, vomiting, diarrhea..all at the same time..caught a bug from someone."

Earlier this week, Germany's Philipp Kohlschreiber, Italian Andreas Seppi, Slovakia's Magdalena Rybarikova and American Bethanie Mattek-Sands had all suffered from stomach bugs.

In a statement issued on Sunday, health officials in the Palm Springs area said the virus had spread across the Coachella Valley, resulting in symptoms of nausea, vomiting, fever and diarrhoea.

"It (the virus) is self-limited and lasts between 24 and 48 hours," the Eisenhower Medical Center said. "It is transmitted by air and direct contact and not passed via food.

"... we have seen increases in overall visits to the emergency department by about 15 percent over the past week. We have seen fans and players at the tournament experience these symptoms as well."