Scientists target silkworms to contain Malaria

Scientists at the International Centre of Insect Physiology and Ecology are using the small factories that silkworm use to produce silk, to manufacture unique antigens on the spot that are key in diagnosing Malaria, with a successful trial expected to greatly curb Malaria spread while creating new demand for silk.

With Malaria tests costing up to US$50 each, doctors in remote tropical regions where these diseases are endemic have to take their best guess at a diagnosis. If they get the diagnosis wrong, they risk losing their patient, and waste already scarce medicine. The high cost is attributed the production and conservation of the antigens in those tests. These proteins react to disease-specific antibodies in the blood to accurately determine which disease is present.

As a result it’s estimated that lack of proper diagnosis of the disease has negated the gains in the war against the disease. Vincent Owino the lead scientist in the project from ICIPE noted that the prevailing problems have necessitated them to figure out how to manufacture antigens on the spot, cheaply and quickly, using silkworms as tiny protein factories.

Silk is a protein, and silkworms make plenty of it. The team hopes to harness their protein-making machinery to produce extra proteins, the diagnostic antigens. “They’re essentially turning the silkworm into a natural, small-scale bioreactor. Using the same genetic techniques used to produce insulin and vanilla flavouring in bacteria and yeast, the team has isolated short sequences of DNA from simple organisms to generate the antigen proteins,” noted Owino.

These sequences will now be introduced into silkworms. When the silkworm caterpillar grows and makes its cocoon, the protein-making factories inside each cell will follow their new instructions to assemble the antigen proteins, in addition to the normal silk. After testing the quality of the antigens and confirming their efficacy in diagnosing disease, the next step will be to breed several generations of the worms, testing constantly to ensure the safety and efficacy of the antigens which are produced.

Lead scientist Vincent Owino said the silkworm system promises to be much cheaper than current antigen production and transport. To get antigens from a factory in Europe to a rural doctor in Africa requires refrigerated trucks, liquid nitrogen and complex cold chain delivery networks, like for vaccines. Silkworms, on the other hand, just need a wooden box with a few mulberry leaves. “With silkworms it will be possible to produce what we need on the spot with very minimal equipment – we won’t even need electricity to diagnose these diseases,” he added.

In addition, the team is also designing a cardboard testing kit, simple enough for use in remote rural health facilities. “We are hoping to make a diagnostic kit that costs less than US$1, and actually we think it could be far below that.”
Their concept is a simple cardboard square. Doctors would put a patient’s blood sample in the centre of the kit, with small tracks fanning out to connect with drops of the antigens for malaria, dengue fever, leishmaniasis or other diseases. A positive test would result in a visible spot on the card.

Owino and the team are currently using the well-established silkworm colony at ICIPE. “The next step will be to scale up, with a cheap and high-yield system that needs only basic facilities and limited skilled labour to keep production costs low. The main cost would be feeding the silkworms to keep their silk production spinning smoothly.”

Currently silk worm farming is steadily rising in Kenya with over 100 farmers’ groups actively engaged in the sctor. To encourage farmers to invest in sericulture the Sericulture Station buys cocoons from farmers at Sh750 for 1 kg of dry cocoons and Sh 350 for wet ones. The station is also connecting farmers with buyers in cottage industries and large textile manufacturers in Kenya, like Rivatex East Africa Limited and Rupa Cotton Mills.

The Kambogo Women's Group from western Kenya's Rachuonyo district and Kimahuri Youth United Self Help Group (KYUSHG) in Nyeri district are among the success stories in silk farming and weaving in Kenya. According to Owino, the success in the new research launched will be a game changer for the venture as more farmers will be brought on board to help raise the needed production capacity.