BHUBANESWAR: Significant rise in aedes albopictus mosquito population possibly due to climate change is the major cause behind spike in dengue cases in Odisha this season, state new entomology studies conducted separately by the Regional Medical Research Centre (RMRC) and the state government.
Earlier, dengue transmission in the state was mostly due to aedes aegypti. As per the preliminary findings of the study by RMRC, more than 70 per cent of the mosquito pool collected from 14 worst-hit areas of Bhubaneswar to study the active transmission of dengue were found to be aedes albopictus.
RMRC director Dr Sanghamitra Pati said, “Every year such entomological surveillance is conducted. For the first time, we have found the presence of albopictus variety in large numbers. Earlier, only one per cent of aedes mosquitoes were albopictus.”
Among the two varieties, aegypti rests indoors, inside a human dwelling or surrounding of the house, during the period between the end of blood-feeding and the onset of searching for an egg-laying site as opposed to albopictus which spends the period somewhere outside the human dwelling.
Both aegypti and albopictus bite during dusk and dawn. People may have been using nets or mosquito repellents inside their house, but the rise in dengue cases could be due to mosquito bites outdoors given the presence of albopictus in large numbers this time, the scientists said.
The entomological investigations conducted by the entomologists of the Health and Family Welfare department of the state government also corroborated the claims. A senior health official said, not only Bhubaneswar, remarkable growth in the population of aedes albopictus has been found from different parts of the state. But there has been alarming growth in the state capital which is why the number of cases in the city is more this year as compared to previous years, he said.
Odisha has recorded 7,795 dengue cases so far this year, the highest in last five years. Khurda tops the list with 3,412 cases (over 3,100 from Bhubaneswar), followed by 908 from Puri, 678 from Balasore and 671 from Cuttack.
The changing climate coupled with other factors like rapid urbanisation leading to increased urban wastes like plastic and hard board products, metal, ceramics and rubber wastes have provided a proper breeding ground for the disease-causing mosquitoes, found the studies.