Three people who recently returned to Chhattisgarh's Durg district from Ebola-affected African countries have been placed under 21-day home isolation as a precautionary measure, health officials said on Thursday, adding that none of them has shown symptoms of the disease or reported contact with infected persons.

Durg Collector Abhijeet Singh said a woman arrived in Durg from the Democratic Republic of Congo on May 31, while two other travellers reached Bhilai on June 2 from Ethiopia and Uganda.

Of the three returnees, two are Indian nationals and one is a Ugandan citizen.

"As none of them have symptoms and there is no history of contact, all three have been placed under home isolation for 21 days. They are currently asymptomatic and in good health," Singh said.

He said health officials are monitoring the travellers through telephonic follow-up twice daily, collecting updates on their health status every morning and evening.

The returnees have also been advised to immediately inform the tracing team, health department, control room or the office of the Chief Medical and Health Officer if they experience any discomfort or symptoms during the observation period.

Durg Chief Medical and Health Officer Dr Manoj Dani said international travellers arriving from Ebola-affected countries, particularly in Africa, are being placed under home isolation for 21 days and are receiving daily health monitoring and medical guidance.

He said passengers arriving from abroad are clinically screened at airports and categorised based on symptoms and contact history.

According to the classification system, Category 1 includes travellers with no symptoms and no contact history, Category 2 comprises those with no symptoms but a contact history, while Category 3 includes symptomatic travellers.

All three returnees in Durg fall under Category 1, indicating they are asymptomatic and have no known exposure to Ebola patients, Dani said.

Officials said no confirmed case of Ebola virus infection has been detected in Chhattisgarh so far.

On May 17, the World Health Organization (WHO) declared the Ebola outbreaks in the Democratic Republic of Congo and Uganda a Public Health Emergency of International Concern.