Fumonisin-producing Fusarium strains and fumonisins in traditional African vegetables (morogo)

In rural settings, African communities supplement grain-based staples with traditional vegetables collectively known as morogo. Mycotoxigenic and mycotic fungi in the agro-environment could have important health consequences for rural communities dependent on subsistence food production. The study reported here used standard techniques for the isolation and morphologically based identification of isolates to investigate the incidence of potential fumonisin-producing fusaria occurring on leaf surfaces of traditional African leafy vegetables (morogo). Fusarium verticil-lioides, F. proliferation, F. subglutinans and F. oxysporum were retrieved in varying numbers from different morogo plants. Typically maize-associated, F. verticillioides and F. proliferatum were the dominant species among isolates from ligusha, a weedy plant growing in maize lands. Fumonisin B group toxins were also detected in varying levels in samples of dried morogo from study areas in different geographical regions of the Limpopo and North West provinces of South Africa. In addition to their toxigenic and carcinogenic potential, strains of these fungal species reportedly cause secondary infections in immunocompromized individuals. In rural subsistence communities with a relatively high prevalence of AIDS, these findings imply additional burdens on HIV-affected immune systems, enhancing the risk of cancer development and secondary infections.