A case of Lassa fever was diagnosed in a man from KwaZulu-Natal on 12 May 2022. The man had extensive travel history in Nigeria before returning to South Africa. He fell ill after entering South Africa and was hospitalized in a Pietermaritzburg hospital. The diagnosis of Lassa fever was confirmed through laboratory testing conducted at the National Institute for Communicable Diseases, a Division of the National Health Laboratory Service. Sadly, the man succumbed to the infection. Currently efforts are underway to trace and monitor all possible contacts. No secondary cases of Lassa fever have been confirmed at the time of this report.
Lassa fever is a viral infection that is endemic to the West African countries and mostly reported in Sierra Leone, Liberia, Guinea, and Nigeria. Lassa fever is less frequently reported from Mali, Burkina Faso, Ghana, Togo, Benin and Ivory Coast. Up to 300 000 cases of Lassa fever, with about 5000 deaths, are recorded annually in the endemic countries. Currently there is no vaccine for Lassa fever.
The natural host of this virus in endemic countries is a rodent species called the multimammate rat. The rats are persistently infected and shed the virus in their urine and faeces. Humans can come into contact with the virus through direct contact or inhalation of the virus in areas that are infested with the infected rats. For example contact with contaminated materials, ingestion of contaminated food or inhalation of air that has been contaminated with urine droplets. Person-to-person transmission of the virus does not occur readily and the virus is not spread through casual contact.
Person-to-person transmission is not common and is mostly associated with the hospital-setting where healthcare workers have contact with the infected blood and bodily fluids of a patient. Cases of Lassa fever in travellers returning from endemic countries are reported from time-to-time. In 2007 a case of Lassa fever was diagnosed in South Africa. The case involved a Nigerian citizen with extensive travel history in rural parts of Nigeria before falling ill and he received medical treatment in South Africa. No secondary cases of Lassa fever were reported in this instance. Recently, in February 2022, an imported case of Lassa fever with secondary cases were identified in the United Kingdom (https://www.who.int/emergencies/disease-outbreak-news/item/lassa-fever-united-kingdom-of-great-britain-and-northern-ireland).
For more information on Lassa fever, visit https://www.nicd.ac.za/diseases-a-z-index/lassa-fever/