Cases of dengue-chikungunya co-infection are on the rise, causing concern to health planners and doctors. About three per cent of dengue-chikungunya cases fall under the co-infection category, with the patient suffering from both the diseases at the same time.

Incidentally, the same Aedes aegypti mosquito transmits both the dengue and the chikunguniya virus; chances of co-infection are higher if the mosquito carries the viruses of both the diseases. A detailed analysis of dengue and chikungunya cases by the department of microbiology, Sri Venkate-swara Institute of Medical Sciences, Tirupati, has revealed that the problem of co-infection is more pronounced in areas where both viruses co-circulate.

Where co-infection strikes, doctors find it hard to diagnose the problem. Though symptoms of these diseases are common, their outcome differs. Tests for both dengue and chikungunya will help in finding whether a patient is suffering from one disease or both of them. Chikungunya is non-fatal while dengue may lead to severe complications including death. The common symptoms of both the diseases include fever, joint and bone pain, nausea, vomiting, headache, and fatigue.

A team of researchers comprising Usha Kalawat, Krishna K. Sharma and G. Satishkumar Reddy analysed 331 samples for dengue and 170 samples for chikungunya. About 12 per cent of dengue samples and 20 per cent of chikungunya samples were positive. The team tested 72 samples for the presence of both dengue and chikungunya antibodies. About three per cent of these samples tested positive for both the diseases.

“Areas affected by the chikungunya virus overlap with dengue fever-endemic areas and provide opportunities for mosquitoes to become infected with both the viruses,” the team pointed out. They added that missing out signs of one disease is always plausible if diagnostic tests for both are not performed and the presence of one does not rule out the other.