Climate Change

Stung by Aedes

Incidence of dengue and chikungunya has grown dramatically in recent years. Let’s understand the impact of climate change on virus transmission and expansion of geographical areas at risk


In the grip of dengue, chikungunya

Changes in rainfall patterns, long spell of warmer temperatures and rise in the humidity level have allowed mosquito vectors to thrive at locations hitherto less known for outbreak of dengue and chikungunya. Unplanned construction projects, stagnation of water and dumping of discarded objects have also made the environment conducive for spread of dengue and chikungunya.

As states grapple with the challenge of spike in number of patients, here is a brief rundown on the extent of damage caused by these vector-borne disease.

Dengue scare in Delhi and West Bengal

Dengue cases have spiralled in three states—Karnataka, Kerala and West Bengal—with Delhi witnessing a sudden spurt in the month of August. The national capital has reported 487 cases of dengue till August 29, with 368 of them being recorded in August alone. In West Bengal, 5,639 people were infected by dengue till August 25 and death toll has reached 23. According to Health Secretary C K Mishra, West Bengal is witnessing a spike in dengue-related deaths because the state has more of Type 3 dengue, while places like Delhi are witnessing Type 2 dengue—a comparatively less virulent strain.

Kerala, Telangana and other southern states

The official data released by the Directorate of Health Services of Kerala shows 279 confirmed cases of dengue between August 20 and 29. Dengue cases have seen a sharp rise in Telangana as well, with more than 175 cases being recorded in Ranga Reddy district (formerly Hyderabad district) till August 14, 2016.

As on August 29, Tamil Nadu has seen over 1,200 dengue cases and five deaths. The state has shown some progress in tackling the spread by identifying breeding sources and running health camps.

Uttarakhand sees a surprise surge in dengue cases

Ever since the first dengue patient in Dehradun was reported on July 13, the number has touched close to 500 within 45 days. According to departmental data, 497 people have been found positive for the disease till August 28. The health experts are intrigued by rapid increase in dengue cases within such a short span of time.

While the total number of dengue cases in Uttar Pradesh stands at 336, this is the report from just four out of 36 laboratories designated by the state health department to conduct dengue testing. The actual figure could be much higher.

Assam witnesses more cases of Type 1 dengue

Assam, which witnessed 1076 dengue cases in 2015, has reported close to 458 positive cases this year (till August 18). The Kamrup district has witnessed the highest number of dengue cases in the state, with over 378 positive cases and one death. However, most of the cases showed the Type 1 strain of dengue.  Other northeastern states, expect Mizoram, which reported one confirmed case of dengue on August 21, are not yet in the grip of these vector-borne diseases.

Rapid surge in Chikungunya cases in Delhi, Pune

While southern states of India are known as traditional hotbeds for Chikungunya virus, the disease has spread its tentacles to other parts of the country, especially Assam, Bihar, Delhi and Uttar Pradesh.

Between August 20 and 27, 412 cases of chikungunya were recorded in Delhi, taking this year’s tally to 432 so far. In comparison, only 20 cases were recorded from January 1 till August 20. This spurt is attributed to city’s "non-immune population". People in Delhi have become more susceptible since Chikungunya virus had not been in wide circulation in the city previously.  According to health experts, Chikungunya cases have been on the rise in the national capital but the instances remain under-reported due to lack of testing facilities and high cost of diagnosis.

Out of 333 confirmed cases of chikungunya in Maharashtra, Pune alone has approximately 289. This is far higher than 66 cases reported cases in 2015. The number of blood samples received has doubled since last year, and the number of positive cases has increased by more than 400 per cent.

Cases of Chikungunya reported in Gurgaon and Hyderabad

Six cases of chikungunya, the first time in the season, were reported in Hyderabad on August 30 by the state-run Fever Hospital.  In Gurgaon, private hospitals are reportedly getting over 50 cases of every day. The first official case of Chikungunya in Gurgaon was confirmed on August 28 when a 35-year-old man from Bihar was tested positive.

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