A 7-year-old boy and his father died Friday, bringing to 10 the number of Indian family members killed after eating poisonous mushrooms in Mexico's southernmost Chiapas state.

All 10, from the community of Tenejapa, had eaten a soup made with wild mushrooms gathered deep in the mountains of Chiapas. Eight other relatives died earlier in the week. The 11th member, a 69-year-old man, did not eat the soup, authorities said.

Wild mushrooms flourish during the rainy season in the forests and jungles of Chiapas, and are a common dietary staple for mostly Indian families. But recent genetic mutations have made some forms of mushrooms consumed for years in Indian communities newly poisonous, officials say.

Authorities have been inspecting open-air food markets, collecting all mushrooms sold there to prevent further deaths.

Medical officials said the type of venom contained in the mushrooms ingested by the family had immediate and severe effects on the liver, making it difficult for doctors to help them.

CountryWatch: Mexico