BONGOR, 29 November 2010 (IRIN) - In the village of Tchinfogo in southern Chad, men and women repeatedly sprint along a dirt path, their tears mixing with sweat as they wail. They go for about 30m before running back and lying on the tomb of a woman who days earlier, at the age of 28, died of cholera.

It is a mourning ritual of the Massa ethnic group, predominant in this part of Chad, Tchinfogo residents told IRIN. Normally, they said, people would also throw themselves onto the body, often hugging and kissing it. But amid a cholera outbreak that as of 24 November had killed 166 people and infected 5,787 across Chad, communities have had to alter their mourning rites.

Government health agents and aid workers working round the clock to treat cholera patients and educate people on how to prevent the disease (left untreated it can kill within hours) must contend with people's desire to visit and touch ailing loved ones, or the bodies of those who have died.

Basile Ema Ebédé, coordinator for Médecins du Monde France in Chad, said in many cases people prefer to follow their customs despite warnings.

"It's quite delicate, and sometimes people don't heed the warnings against contact with the bodies of their loved ones."

Cholera is an acute diarrhoeal infection caused by ingestion of food or water contaminated with the bacterium Vibrio cholerae. But a person can contract cholera and other gastrointestinal infections by being in contact with a body, as dead bodies often leak faeces, according to the World Health Organization; transmission can occur through direct contact with the body and soiled clothes or contaminated objects.

Recently local workers with Intermón Oxfam in Chad's southern town of Bongor had to bury the body of a two-year-old girl in the absence of her parents.

"They were far away in another village," Tounsou Gabriel Wananga, a worker with Intermón, told IRIN. "We waited a bit but couldn't wait any longer; we had to bury her, with some elders from the family present."

One day later the girl's parents were back in the village, sitting among relatives to mourn the death of their already buried daughter.

"What can we do?" the father, Damma Mouraïna said. "We must keep our composure and be strong; it's an epidemic so we must just accept."