Is there a risk of catching malaria in Namibia or South Africa
Yes. According to the CDC, malaria is present in the following areas of Namibia: Kunene, Ohangwena, Okavango, Omaheke, Omusati, Oshana, Oshikoto, and Otjozondjupa and the Caprivi Strip. In addition, malaria is present in South Africa in northeastern KwaZulu-Natal Province as far south as the Tugela River, Limpopo (Northern) Province, and Mpumalanga Province. It is also present in Kruger National Park.
If you are visiting these areas, it is recommended you take prophylactic medication (such as doxycycline, mefloquine or atovaquone-proguanil) and sleep under a bednet. Other preventative measures against mosquito bites, such as wearing long-sleeved clothing and insecticide on exposed skin (especially in the evenings and at night) are also recommended.