Odisha Malaria ‘Daman’ gets a boost, ILS, Bhubaneswar devises test-kit for Asymptomatic Malaria

For lack of testing tech, identification of asymptomatic carriers in the endemic areas is proving a major hurdle. Even, Rapid diagnostic tests (RDTs) miss out about 30-50 per cent of low-density infections

Bhubaneswar: Even as Odisha has nearly halved the total Malaria cases in the State in year 2019, the threat of the vector borne disease to the public health in the State still looms large.

Odisha’s public health faces a threat from consistent build-up of the asymptomatic sub-patent parasitemia in the endemic communities, who  act as the infectious reservoir for continued transmission. And identification of asymptomatic carriers in the endemic areas is proving  as a major hurdle.

Burden of Asymptomatic Malaria in Odisha: As per a study published in PLOS (Public Library of Science) One on prevalence of afebrile malaria in Odisha, plasmodium falciparum is detected in 21 per cent of febrile blood smears taken; whereas in afebrile status, the proportion was estimated at a high of 79 per cent.

Similarly, the proportion for the P vivax in febrile vs afebrile stood at 11 per cent : 81 per cent, respectively. The proportion for the mixed infection also stood at 24 per cent to 76 per cent, respectively.  

At present there is no built-in mechanism to detect the  asymptomatic cases or even low-density/sub-patent parasitemia in the endemic communities in Odisha.

Even, the Light microscopy and protein immunoassay-based rapid diagnostic tests (RDTs) used in the diagnosis of Malaria via mass screening and treatment programs for the diseases miss out about 30-50 per cent of low-density infections, which typically have less than two parasites per microlitre and are frequently observed in asymptomatic carriers.

However, a ray of hope emerges over the eastern horizon of the country. India has set the target to become Malaria free by 2030.

The Bhubaneswar-based Institute of Life Sciences (ILS) in association with Bengaluru-based Jigsaw Bio Solutions have come up with a technique to overcome the problem of inadequate identification of asymptomatic carriers of the disease.

As per an ILS release, a researcher team led by Dr. V. Arun Nagaraj of Institute of Life Sciences and Srinivasa Raju of Jigsaw Bio Solutions Pvt. Ltd used a new concept of genome mining that identifies identical multi-repeat sequences (IMRS) distributed throughout the malaria parasite genome and successfully targeted them to develop what is called an “ultra-sensitive” qPCR assay for malaria diagnosis.

In order to validate, clinical samples were collected from malaria endemic regions in the country. The result has been enthusing as the evaluations show that the assays were highly sensitive – about 20-100 times more than the traditional methods. It was found that qPCR could detect even submicroscopic samples.

The “ultra sensitive” technique seems four to eight times better than other high-sensitive methods. Moreover, they were extremely specific for Plasmodium falciparum, which is the deadliest species of malaria parasite and did not cross-react with Plasmodium vivax species – the most frequent and widely distributed cause of recurring malaria.

“Our study could lead to the development of highly sensitive, point-of-care molecular diagnostics that can be explored in miniaturized, isothermal, microfluidic platforms and lab-on-a-chip devices. The IMRS (identical multi-repeat sequences) approach can serve as a platform technology for the diagnosis of other infectious diseases as well,” said VA Nagraj.

MALARIA FACTOIDS: Total Blood Slides Examined in Odisha in 2019: 65.51 lakh. Slide Positive rate : 0.60. Total Malaria cases: 39,557. Plasmodium Falciparum  cases: 90.44 per cent or 35,775. Slide falciparum rate: 0.55. Malaria positive cases in 2019 down by 40 per cent, Falciparum cases drop by 33 per cent.