Malaria, dengue detection made easy

Doctors evolve mathematical formula to pinpoint most likely cause of fever

By Jyotsna Singh
Published: Monday 08 July 2013

Patients suffering from high fever are often put through a series of tests to detect the cause of fever. They end up spending a few thousand rupees on diagnostic tests (malaria test costs up to Rs 750 and the one for dengue costs up to Rs 4,500). What's more, their treatment gets delayed pending cofirmatory tests. But now there is now hope for such patients whose suffering is prolonged owing to the number of tests they undergo.

How the new formula helps
Present scenario:

  • Patient suffers high grade fever, chills and bodyache
  • Patient suspected for either malaria or dengue or viral fever
  • Antibiotics instituted for patients till specific results come in
  • Common tests ordered for all patients:
    1. Complete blood count
    2. Peripheral blood smear for malarial parasite
    3. Malaria antigen.
    4. Blood culture.
    5. NSI antigen for dengue
    6. Dengue serology
    7. Urine (routine & microbiology)
    8. Chest X-ray
  • Proper treatment starts after confirmation

Future scenario:

  • Patient suffers high grade fever, chills and bodyache
  • New test performed: Complete Blood Count + VCS indices in LH750 Analyzer
  • Results in 1 hour
  • Disease pattern found
  • Proper treatment in most cases starts
  • One of the following tests to be conducted for confirmation:
    1. Dengue Serology & NS1 Antigen tests
    2. Malaria Parasite (MP) & Malarial Antigen tests
    3. No specific tests needed
The doctors of Sir Ganga Ram Hospital (SGRH) in Delhi have developed a mathematical equation to solve the problem. The equation will run on laboratory information system (LIS), a software-based system which has features that support a modern laboratory's operations. Data on red blood cells of a patient would be fed in the equation on the system.

In a matter of one hour, after analysing the data, the system will indicate with which illness the pattern of data matches. The doctors can then start treatment for that particular illness and ask the patient to go for only one test for confirmation. The test will cost Rs 200 in hospitals where LIS is available.

It is a sytem that is normally found in tertiary care hospitals and advanced clinics. The test includes complete blood count using VCS (volume, conductivity, light scatter) technology.

High rate of success

"The sensitivity of the test is 86 per cent, while specificity is 91 per cent. With this high success rate, very few people will be detected wrong who will have to go for the test for the other illness too," said Manorama Bhargava, chairperson, department of hematology, SGRH and part of the team that developed the model.

The model already existed for malaria. But it's the first time in the world that a model has been developed for dengue, making it possible to differentiate between dengue, malaria and viral diseases at an initial stage.

The model was prepared after a study conducted among patients from April 2010 to March 2011, results of which were published in the June 15, 2013 issue of International Journal of Laboratory Hematology. The researchers collected 324 samples to collate data of dengue, malaria as well as patients with non-specific febrile illnesses that mimic the two.

"The parameters used in the model are not dependent on environment and the region of the patient. Hence, it is universally applicable," said Bhargava.

Malaria and dengue cases and deaths in India
2010 2011 2012 2013
Malaria 1,563,574/1144 1,599,986/1,018 1,310,656/754 1,066,981/519 200,048/51
Dengue            15,535/96 28,292/110 18,860/169 50,222/241 11,591/41

In India, dengue and malaria outbreaks are common owing to poor sanitation and drainage syatem. In 2013, till June 30, 51 people died of malaria, and 41 of dengue (see table). According to the National Vector Borne Disease Control Programme (NVBDCP) data, till June 30, there were 200,048 detected cases of malaria and 11,591 detected cases of dengue. Also, India has high incidence of Plasmodium falciparum (Pf) type malaria.

It is not only a deadlier type, but its symptoms are closer to dengue, making its early detection tough. In 2013, 117,680 cases of Pf malaria were detected, which is nearly 50 per cent of the total number. Trends of the last few years show the same. In 2009, Pf malaria cases were 50 per cent of the total numbers, in 2010 it was 51 per cent, in 2011, it was 52 per cent and in 2011, the figure was 54 per cent.

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