MILWAUKEE — The Milwaukee County Zoo says the deaths of two lowland gorillas have been linked to gastrointestinal infections likely caused by E.coli in their water supply.

The zoo Thursday released results of necropsies of the 31-year-old male gorilla Cassius who died April 12 and 17-year-old female Naku, who died April 28.

The Milwaukee zoo says the water systems in both the gorilla and bonobo areas have been disinfected. Staff are also using new protocols to disinfect produce, which can be another source of E.coli.

Cassius and Naku's 8-month-old baby, Zahra is one of three remaining gorillas in the same family group. Cassius also sired a baby Sulaiman with Shalia, an adult female. Sulaiman is 4 years old. Two other male gorillas at the zoo are not part of the family group.