Molecular identification and distribution of viruses associated with African cassava mosaic disease in Sankuru province of Democratic Republic of Congo

Cassava (Manihot esculenta Crantz) is a staple crop in Democratic Republic of Congo (DRC), where its roots and leaves are an essential daily food for the population. However, Cassava Mosaic Disease (CMD) severely disrupts production systems of the crop, with losses reaching 90%. The objective of this study was to identify the viruses responsible for CMD and establish their geographic distribution in Sankuru Province, DRC. Epidemiological surveys were conducted, following the standard protocol adapted by Central and West African Virus Epidemiology (WAVE) programme. A total of 309 cassava leaf samples, exhibiting CMD symptoms and symptom free features, were collected from 103 fields distributed across four territories (Katako-Kombe, Lomela, Lodja, and Lubefu) in the Province. The mean rate incidence and mean severity in the field were 86.88% and 3.16, respectively; indicating that the Province was highly infected with CMD. Molecular PCR analyses revealed an overall infection rate of 73.46%, with the detection of ACMV, EACMV, EACMV-Ug, as well as other unidentified Begomoviruses. Mixed infections, including triple infections (ACMV+EACMV+EACMV-Ug), were also observed. Results indicate a significant predominance of ACMV and unidentified Begomoviruses, followed by mixed infections, with a variable distribution across different areas. The detection of unidentified viruses in several samples suggests the presence of variants that are still poorly characterised; requiring further sequencing studies. These results highlight the importance of molecular surveillance for effective management of CMD in this Province.