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Development and evaluation of a 1-step duplex reverse transcription polymerase chain reaction for differential diagnosis of chikungunya and dengue infection

7 Jul 2008

Marcia Triunfol

Source: Diagnostic Microbiology and Infectious Disease (see original article)

Citation: Dash PK, Parida M, Santhosh SR, Saxena P, Srivastava A, Neeraja M, Lakshmi V, Rao PV. Development and evaluation of a 1-step duplex reverse transcription polymerase chain reaction for differential diagnosis of chikungunya and dengue infection. Diagn Microbiol Infect Dis. 2008 Jun 24.

The rise of many infectious diseases, especially of those transmitted by mosquitoes, is in large part attributable to global warming. It is predicted that global warming will continuously increase the incidence of infectious diseases, especially of arboviral infections in warm areas, as mosquitoes and arthropods in general are very sensitive to climate conditions.

One such arboviral infection on the rise is dengue, which is considered the most important arboviral infection of the present day, causing millions of infections and a significant number of deaths in tropical and subtropical endemic areas. Unfortunately, dengue is not alone. Other threatening arboviral infections are also emerging. An important example is chikungunya, an arboviral infection that causes similar symptoms to those seen in dengue patients, and which is spread over the same geographical area.

Both dengue and chikungunya are viral infections transmitted by the Aedes mosquito. However, while dengue is transmitted by Aedes aegypti, chikungunya is transmitted by Aedes albopictus. For neither of these two diseases is there a vaccine or specific treatment.

Chikungunya is characterized by fever, rash, myalgia, and arthralgia, but causes no fatalities, whereas dengue sometimes develops into dengue haemorrhagic fever, which is a severe and sometimes lethal form of the disease that requires more aggressive treatment. Therefore, distinguishing the two infections as early as possible is crucial to increase the patient’s chance of a successful outcome.

Currently, dengue and chikungunya are diagnosed by isolating the virus, or by detecting antibodies in patients’ serum. These approaches present some drawbacks, as isolating the virus can be time-consuming and laborious and antibody detection is only possible during the acute phase of the disease because levels are too low. More recently, diagnosis has also been done using molecular techniques that detect the genetic material of the virus, which in both dengue and chikungunya is made of RNA. This approach, known as the reverse transcription polymerase chain reaction, has shown to be very sensitive and it has also been used for the detection of many other viruses. However, for each of the viruses under investigation, a new reverse PCR reaction needs to be done.

In this paper, Dash and colleagues show that PCR amplification of either dengue virus or of chikungunya virus can be performed in the same reaction tube, in a single 4-hour PCR reaction, requiring that two pairs of primers, one specific for dengue and another for chikungunya are added to the mixture.

Besides accelerating diagnosis, this innovative approach also allows identification of those patients who are infected with both viruses, and who usually are not tested any further, if a positive result for one of the infections is obtained. This approach may also be further developed to include PCR primers for other vectors that already circulate in the same habitat or may do in the near future, as climate continues to change.

Note: This article is published in a journal which is not open access. To see the full article a subscription to Diagnostic Microbiology and Infectious Disease is therefore required. In some developing countries, readers who are based in institutions may be able to access it through the HINARI programme.