Few of the Afghans who returned from Iran were tested before they fanned out across the country to their homes.
The US Embassy Spokesperson in New Delhi said they are working with the health authorities here to ensure the employee receives proper treatment.
Delhi government sources on Saturday said Kejriwal and Sisodia will not attend the event as their names were dropped from the guest list.
In describing the working relationship, Arun Sharma, president of the Society for Indoor Environment, said, "This project could only be implemented because of support from the US Embassy in Delhi."
Numerous Iraqi citizens have gathered outside the US embassy premises.
Demonstrators gathered in front of the former U.S. Embassy in downtown Tehran as state television aired footage from other cities across the country.
Since weekly border marches began in late March, 42 Palestinian protesters have been killed and more than 1,800 wounded by Israeli army fire.