Fishes in the backwaters of the Zambezi river have been infected with a deadly but unidentified infection. It was strongest upstream in Namibia and Zambia. The fatal infection was first noticed by Namibian fishers in October. It is feared some villagers may have eaten infected fish. Christopher Magadza, a specialist in Zimbabwe, warned some fish parasites could be transmitted to humans. Samples are being examined to find the cause, extent and consequences of the infection.