A group of monkeys being transported on a Mississippi highway that escaped captivity Tuesday after the truck carrying them overturned did not carry a dangerous infectious disease, a university has said.

The truck was carrying rhesus monkeys, which typically weigh around 16lbs (7.7kg) and are among the most medically studied animals on the planet.

Video shows monkeys crawling through tall grass on the side of Interstate 59 just north of Heidelberg, Mississippi, with wooden crates labeled “live animals” crumpled and strewn about.

The local sheriff’s department initially said the monkeys were carrying diseases including herpes, but Tulane University said in a statement that the monkeys “have not been exposed to any infectious agent”.

All but one of the escaped monkeys were killed, the Jasper county sheriff’s department said in a post on Facebook, warning that the monkeys were “aggressive”.

They were being housed at the Tulane University National Biomedical Research Center in New Orleans, Louisiana, which routinely provides primates to scientific research organizations, according to the university.

The crash happened about 100 miles (160km) from the state capital of Jackson. It was not clear what caused the truck to overturn.

The Associated Press contributed to this report