East African scientists turn to gene sequencing against 'Ebola of plants'

Story highlights

  • Whitefly-borne disease destroys over $1 billion worth of cassava
  • Fresh outbreak inflicts dire humanitarian crises
  • Scientists turn to gene-sequencing technology to fight disease

(CNN)Almost a billion people around the world rely on cassava as a staple food. The root vegetable is a versatile and calorie-rich crop that is resilient enough to thrive in harsh climates.

But the cassava has no defense against a tiny insect that is decimating crops across East Africa, with dire economic and humanitarian consequences.
The whitefly carries two viruses that together destroy over $1 billion worth of cassava in Sub-Saharan Africa each year. Cassava Mosaic Disease (CMD) is the more established threat and does most of the damage. But scientists are even more alarmed by an outbreak of Cassava Brown Streak Disease (CBSD) - dubbed the "Ebola of plants."
    The disease is highly infectious, difficult to detect, and it mutates rapidly into new strains. Farmers often discover the tell-tale brown streaks only after their entire crop has been destroyed.
    The outbreak could have a catastrophic impact if it continues to spread. But local specialists are working with an international coalition and state-of-the-art technology to defeat it.
    Tell-tale signs of Cassava Brown Streak Disease (CBSD).

    Mapping disease

    Great swathes of Tanzanian farmland have been wiped out by CBSD.
    "We are seeing very severe food shortages," says Dr. Joseph Ndunguru, a plant virologist based in the East African state with the Cassava Diagnostics Project (CDP). "Farmers are just abandoning their crop, and in some areas cassava is the only staple food."
    The CDP is working in seven countries in East and Central Africa, educating farmers and local government about the problem, studying the spread of disease, and developing resistant varieties of cassava.
    "We generate maps to show the distribution of virus strains in all of the project countries," says Ndunguru. "We use them to decide where to deploy clean plant material."