Health experts have raised concerns about the ongoing cholera outbreak in southern Africa, saying there's a high possibility of continued importation of cases.

This was revealed during a cholera outbreak webinar on Tuesday organised by the Department of Health.

The department announced on Monday that 15 people in Hammanskraal, outside Pretoria, died of cholera. Others are in hospital.

Chief director of environmental and port health services Aneliswa Cele said cholera had become a global concern.  

She said the purpose of the webinar was to collectively address the implications, better equip frontline healthcare workers, improve case management, create awareness about other threats, and refresh and update existing knowledge with just-in-time reminders.

"As of May, cholera cases are still being reported in at least 24 counties globally. South Africa is among the 15 African countries that have experienced a cholera outbreak. This is not the first time we are experiencing this as a country; we have been through this before," Cele said.

She added that the primary transmission mode had been linked to climate change; limited access to clean water, sanitation and hygiene services; and, in other cases, armed conflict.

She said more than 1.1-billion people were at risk and that children under the age of five were particularly vulnerable.

With the rapid increase in the number of local transmissions and associated deaths, Cele said clinicians were urged to maintain a high index of suspicion for cholera in patients who present with acute watery diarrhoea. Surveillance measures should also be strengthened to enable early detection.

Dr Juno Thomas of the Centre for Enteric Diseases explained that the hallmark of cholera was acute watery diarrhoea that lasts less than seven days.

"Any acute watery stool, regardless of colour, must be considered suspected cholera. When it comes to diagnosing cholera, culture remains the recommended diagnostic method. The first step in diagnosing cholera is to suspect it. If the appropriate transport media and selective media aren't used, the likelihood of detecting V. cholerae is low," she said.

She added that healthcare workers should ideally alert the laboratory before submitting a specimen from a suspected cholera case to optimise specimen transport and processing.

"Cary-Blair transport media must be used when submitting a faecal swab," she added.

Thomas said the National Institute for Communicable Diseases (NICD) could not process all routine specimens.

"Culture must be performed at the nearest microbiology lab to optimise organism recovery. [The] NICD will assist with confirmatory testing of all V. cholerae and PCR on faecal specimens on a case-by-case basis only; not appropriate or feasible for all specimens," she said.