Detecting cholera in 15 minutes

Scientists at the icddr,b, in partnership with Incepta Pharmaceuticals, have  developed a low-cost device  which can detect cholera in only 15 minutes.

Called Cholkit, the tool has generated hopes of better management of cholera and if commercially produced, it will reduce dependence on imported testing kits and might be exported as well, scientists said. 

“Presently, in addition to the laboratory culture of stool samples, imported rapid diagnostic test kits are being used for cholera detection,” said Dr Firdausi Qadri, the lead scientist in the project who works in the Infectious Diseases Division at icddr,b.

An estimated 1.3 billion people globally are at risk of cholera, with South Asia constituting the largest share, which makes the device export-worthy. 

More importantly, Cholkit comes as a blessing for many in Bangladesh where at least 66 million people are at risk of cholera.

Moreover, nearly 110,000 cases are reported annually, according to a statement of icddr,b yesterday.

Scientists said the rapid diagnostic test (RDT) went through a rigorous three-year research and development process and successfully met requirements and guidelines for tests capable of detecting Vibrio cholerae from stool. 

To use it, the device is dipped into a tube with stool specimen and then in 15 minutes it provides qualitative result (coloured band) which is readable by the naked eye. 

A field evaluation of Cholkit has recently been published in the scientific journal “PLOS Neglected Tropical Diseases” which showed the sensitivity and specificity of the dipstick to be similar to the commercially available rapid diagnostic test (RDTs) for detecting Vibrio cholerae from stool specimens.

A total of 7,720 stool samples were tested during the evaluation. Cholkit demonstrated a sensitivity of 76 percent and specificity of over 90 percent, while other RDTs showed around 72 percent and 86.8 percent respectively.

The gold standard for detecting cholera is laboratory confirmation by stool culture, which is sensitive to several factors, including the quality of sampling, delays in shipment, laboratory equipment, skilled human resources.

It also needs longer period of time (24 to 72 hours) and costs $6 to 8 per sample, icddr,b says. 

Cholkit is priced around $3, said icddr,b. Officials, however, said they could not specify its commercial price or when it would go into production but added it would be soon.

The kit has been found to be highly effective in detecting V cholerae serogroup O1 and has received official licensure, said icddr,b. 

From a public health perspective, cholera outbreaks need immediate and early detection as the pathogen can spread and cause epidemics in a short period of time, it said.

“Thus, the need for simple and easy to use RDTs, which are quickly interpretable, require simple storage facilities, and are reasonably priced is a clear choice,” icddr,b said. 

It has the potential to be used at the primary health care level for cholera surveillance, for early outbreak detection and as a tool for an initial alert for monitoring of seasonal peaks in highly endemic areas and in peripheral health care facilities, it said.

The Incepta-produced Cholkit is now being used in 22 cholera sentinel surveillance sites across Bangladesh. The sites are managed jointly by icddr,b and Institute of Epidemiology Disease Control And Research.