Three traders, who crossed into Zambia illegally and were arrested, have been deported from the neighbouring country.
The traders crossed into Siavonga through illegal crossing points along the lower part of the Zambezi River before they were intercepted Zambian immigration authorities.
They spent about a week in quarantine before being deported at the weekend.
Kariba district medical officer Dr Muza said the three had since been transported to Chinhoyi.
"They were transported to Chinhoyi Quarantine Centre on Monday for mandatory quarantine until they are cleared by health authorities that they are fit to be integrated into the community," said Dr Muza.
Health authorities have expressed concern at the number of people crossing in and out of the country through undesignated points along the Zambezi River, fearing the spread of Covid-19.
Kariba Municipality environmental health officer Mr Moses Tawedzera has been conducting awareness campaigns supported by the Zimbabwe Chamber of Informal Economy Association (ZCIEA) on the dangers of harbouring returnees. This comes as Kariba has recorded its first Covid-19 case.
"We now have a confirmed case of Covid-19 in Kariba and we need to double our effort to reduce the spread of the disease," said Mr Tawedzera.
"This is not the time to relax. In our homes, in public and even our workplaces, we need to be extra cautious. Those in enclosed workplaces should make sure they put on their masks at all times."
ZCIEA member Donald Chivandikwa urged people to notify health authorities if they suspected someone could be affected by Covid-19.
Zimbabwe has a worrying proportion of imported cases, but local transmissions have in recent weeks overtaken those imported, giving health authorities sleepless nights on issues like contact tracing.
President Mnangagwa recently announced the tightening of lockdown measures and imposed a curfew from 6pm to 6am in a bid to curb the spread of the virus,.
"Our major concern is that we are beginning to see an increase in the number of locally transmitted cases which exposes a lot of people in the country," said Mr Tawedzera.
"We are monitoring the house where one person tested positive for Covid-19 in Nyamhunga suburb. People there are quarantined for a period of 14 days until they are cleared."