Jennings, the Olympic 10,000m bronze medallist, had her appendix removed yesterday. The American, who had flown in from Boston the previous day, woke up complaining of stomach pains and hotel staff alerted the hospital.
A spokesman for the organisers of the World Cross-Country Challenge said: 'It's disappointing she won't be able to race, but we are glad she is all right.'
John Ngugi's withdrawal from the men's race has lined up a showdown between the Olympic bronze medallists William Mutwol and Fita Bayisa. Mutwol, the late replacement for his fellow Kenyan, Ngugi, was runner-up to the five-time world champion in Boston this year as well as winning bronze in the Barcelona Games steeplechase. Ethiopia's Bayesa, third in the 5,000m in Barcelona, was also third in Boston.
In Brazil yesterday, Kenya's Simon Chemwoyo held off a late challenge by the defending champion Arturo Barrios, of Mexico, to win the San Silvestre 15km road race, four days after winning a cross-country event.
Chemwoyo became the first African to win the race, run through the streets of Sao Paulo every year since 1925, finishing in 44min 8sec to deny the world 10,000m record holder, Barrios, his third successive victory. Johnny Pazin, of Brazil, finished third in 44:55.
Mexico continued their dominance of the women's race when Maria del Carmen Diaz won for the third time in four years. Diaz won in exactly 54 minutes, finishing 19 seconds ahead of the Brazilian, Carmen Furtado de Oliveira. Martha Tenorio, of Ecuador, came third in 54:39.Reuse content