How climate change has altered the rules of Odisha's battle against vector-borne diseases

Diagnostic center in Odisha
News 18
Odisha, India
How climate change has altered the rules of Odisha's battle against vector-borne diseases

When her four-year-old son fell ill, racked by fever, Shampa Das immediately thought of the time when she had nearly died of malaria. Back then, nearly four decades ago, no one in her village had heard of it. While she survived, the experience made her acutely aware of the dangers that mosquitoes pose and Shampa always took precautions, ensuring her son never slept outside a mosquito net.

So she was surprised when the doctors told her that he was bitten during the day and that it wasn’t malaria he had contracted but dengue.

“I had never even heard of the disease,” she said while peering to see if the queue ahead of her at the Sriram Chandra Bhanja (SCB) Medical College and Hospital in Odisha state had budged. It hadn’t.

Shampa is not alone. Back in 1980, the year that India had its first recorded incidence of a dengue epidemic in modern-day Chennai, the SCB medical college existed as a small dispensary that looked to treat pilgrims suffering from, among other diseases, malaria. Since then the focus for the state has been malaria. From 2001 to 2017, a total of 3,320 people died of malaria, as per state records. That is, on average, 195 people every year — or a malaria death every two days. Sustained efforts, though, focused at specific districts and areas earlier left untouched, resulted in an 87 percent decline in malarial deaths from 2017-18.

But increasingly that incredible success, on which India's plan to eliminate malaria by 2027 rests, is being compounded by concerns over an overburdened health system and economic inequality in a changing climate.

Crowded corridors at Odisha hospital
Concerns about the inadequacy of Odisha’s health infrastructure is writ large upon the hospital’s sprawling campus. Crowded corridors are filled sick patients who lie in a daze, on the floor / Credit: Aniruddha Ghosal

In 2006 a mysterious fever that was accompanied by severe headaches, unbearable muscle and joint pain and debilitating fatigue broke out across the country, leaving doctors baffled. By the time the National Vector Borne Disease Control Program (NVBDCP) in Odisha identified the disease as dengue in 2011, 38 people had died. Japanese encephalitis (JE), another vector-borne disease (VBD) - illnesses transmitted by insects such as mosquitoes, ticks, and fleas - was recorded for the first time in 2011, and in 2013, with four positive cases, chikungunya left its mark on the state.

Today, the prevalence of chikungunya and JE is minuscule, with the latter being impacted by other factors including toxins present in fruits. But dengue is another matter, with an average of 4,200 cases each year, and is fast becoming the most prominent emerging challenge for Odisha.

VBDs are directly impacted by myriad factors, ranging from migration to urbanisation, from trade to temperature. But increasingly, the state and its public health system are zeroing in on the link with climate change, perhaps unsurprisingly.

Knowledge of climate change in Odisha is as ubiquitous as shops selling mosquito nets. The Indian government has declared the state disaster-affected for 95 of the past 105 years. In 1998, a heatwave killed an estimated 2,200 people. From 1891-1970, the state saw 952 cyclones and 451 tornadoes. From 1963-99, the state faced 13 major disasters that killed 22,228 people.

In the midst of these ravages, however, the government is only now realizing the risks of the more "gradual" impacts of climate change. The challenge for Odisha, like the rest of India and, in fact, the world is to not just try and predict the impacts of climate change and design health policies accordingly but to also account for the ways in which lives are impacted, and often, lost. With dengue outbreaks in Himalayan states like Uttarakhand and Kashmir and malaria finding new ground, Odisha’s experiences are vital for the country.

In this series, News18 will focus on the state’s efforts to combat vector-borne diseases, interrogate the varying, and often surprising ways, in which climate change is impacting this fight and also look at what this means for the country, and consequently the world.


In 1953, British entomologist Michael Thomas Gillies, while researching malaria in modern-day Tanzania published a paper confirming how in warmer climates, “adult female mosquitoes digest blood faster and feed more frequently, thus increasing transmission intensity.” Sixty-four years later and 6,260 kilometers away, his research continued to inform and influence two researchers who asked the same question, albeit in a different context. What exactly does this mean for Odisha, a state with hills and dense forests, along with coastal cities?

Mithun Karmakar of the National Health Mission (NHM) in Odisha and Madan Mohan Pradhan, who at the time was with NVBDCP-Odisha, decided to look at heat waves as an indicator of climate change in a study. Upon analyzing the data they found that up to 2002 the month of May was “characterized by a higher number of heatwave days.” But consequent years have “experienced a higher or equal number of heatwave days in ...June” — a period usually associated with the onset of the southwest Monsoon. This, they argued, could be “an indicator of a gradual shift of monsoon season in Odisha.”

Other experts echoed this finding. KJ Ramesh, former director-general of the Indian Meteorological Department (IMD) and senior advisor to the Ministry of Earth Sciences for atmospheric sciences and climate since 2007, explained that scientists have been observing a delay in the withdrawal of monsoons since 2010.

"From 2010, one sees that the length of the monsoon has become longer," he told News18.

What these studies show is that weather conditions favorable for mosquitoes to breed, bite and infect have extended to nearly half the year.

Heat-related deaths graphic

“The longer duration of rainfall…it is happening, not just in Odisha, but across the globe. So, the breeding time for mosquitoes has also risen," Ramesh said.

There are a few reasons why climate change may increase dengue risk. First, the incubation period of the virus shortens in warmer temperatures, which means a mosquito doesn’t have to survive as long to have a chance of becoming infectious. Second, the range of places in which the mosquito can survive is increasing due to global warming.

In general, climate is a key factor controlling where a species can live. When the climate changes, individuals move to stay in a suitable habitat. Back in the 1970s, dengue was present in less than 10 countries. Since then, with warming temperatures increasing the area where mosquitos and live and thrive, dengue has spread to more than 120.

Although it is fatal in less than one percent of the total cases, there is no medical cure for it, nor a vaccine that has widely been approved. Researchers say that with unpredictable rainfall patterns and rising temperatures, more than 500 million people could be at risk of contracting diseases like dengue in the next three decades. A major cause of worry is that the extent to which the mosquito and the viruses it harbors could adapt to warming temperatures is not known.

Limited evidence of chikungunya, for instance, shows that changes in temperatures could impact the virus strain, found a study. This is critical in the case of dengue since there are four strains and those infected with a particular strain develop a resistance to it. But if they are later infected with a different strain, they’re more likely to develop a severe case of dengue.

Dr. Ramesh C. Dhiman, of the ICMR-National Institute of Malaria Research, said that the “developmental cycle as well as the development of pathogens in [the mosquito's] body depends on temperature.” 

Consequently, vector-borne diseases are “seasonal diseases, that is, particular months in a year are suitable for transmission,” he said. For instance, states like Chhattisgarh and Jharkhand have 10 months that are suitable for the transmission of malaria, while in the northern states with colder winters this is restricted to about half the year. “Due to projected increase in temperature, there may be an extension in the months of transmission by 1-3 months in some areas thus widening the window of transmission,” he warned.

“We are now adapting our program, altering it to cope with climate change and in response to climate change,” said Karmakar.

In June, the Odisha government launched a drive to create awareness among residents about vector and water-borne diseases, in particular, malaria, dengue and diarrhoea. This effort, Karmakar said, was in “direct response to climate change.” Their research has also confirmed that while dengue and chikungunya are more prevalent in urban areas, malaria and JE are more likely in the hilly, forested districts.

Malaria occurence in Odisha


Dengue occurence in Odisha


Chikungunya occurences in Odisha


Japanese encephalitis cases in Odisha

Importantly, health officials said that the department would also work alongside allied departments — Panchayati Raj, water and sanitation, education, women and child welfare and industries.

“This has to be a concerted effort from the government as a whole,” added Karmakar, explaining that it is not something that can be tackled by the health department alone. She added that climate change had forced authorities to adopt a response plan. “Earlier, it was more focused on [extreme events like] floods and heatwaves. We are now modifying it. Now, the program implementation plan has a separate component of climate change.” This, she explained, was a fundamental change in how the government was looking at the issue itself since the program implementation plan defines the contours of what the program is trying to achieve and how it aims to do so.

Although Odisha health secretary Pramod Meherda didn’t respond to repeated requests for comment, an official of the NVBDCP office at Bhubaneshwar, who did not wish to be named told News18, “The impact of climate change is being reflected. As we see here, there was a dip [in VBDs] in 2013. But at the same time, India and the world had a similar dip. No government can afford to be casual.”

Pradhan, who had helped the government streamline its program to tackle malaria, agrees. The science is clear, he says, “An increase in temperature will mean that mosquitoes will thrive in areas where they don’t exist today. The parasites will also be influenced. The vector will be influenced. The climate will become favorable for it. Also, due to climate change, there may be displacement of population and they may be unprotected,” he said.

The NVBDCP office is known by most as the "malaria office" in Bhubaneshwar. Flanked by hospitals and pharmacies, it is here that the state’s surveillance of vector-borne diseases is controlled. But back in 2010, when dengue first emerged, the systems were simply not in place. “We just couldn’t make out that it was because of dengue…in one area, there were 11 deaths. It was suspected to be a viral fever,” the official said.

VBD deaths in Odisha


VBD deaths in Odisha page 2

Since then, the official said that the health department has worked closely with the Regional Medical Research Centre to identify potential problems and work fast to find solutions. The state also has 38 sentinel sites, from where it gets high-quality data about vector-borne diseases to ensure that the state is not caught by surprise again.

Still, Pradhan, who grew up in a small village and is now posted in Boudh district, a tribal-dominated area, admitted that he was worried about the government “becoming relaxed,” and said a further scaling up of infrastructure was urgently needed in the state. He said that the state’s success in bringing malarial numbers down was nothing short of "historic."

“In public health, people love to treat the patient. But not prevent the disease. Prevention is difficult. We have not given it much attention.”


Pradhan’s concerns about the inadequacy of Odisha’s health infrastructure is writ large upon the SCB Medical College and Hospital's sprawling campus. Crowded corridors are filled with sick patients who lie in a daze on the floor. A fevered man holds on to his young wife’s hand. She looks resolutely at a closed door, perhaps willing it to open. Others, perhaps knowing the limitations of an overburdened public health system, camp through the night.

In spite of the recent strides Odisha has taken, the innate difficulties the state faces were reflected by Odisha slipping to the bottom of the 21 large states in India, as per the performance of its overall health indicator, in a report by the government's policy think-tank, NITI Aayog. Even if doctors are able to address dengue and other VBD outbreaks, preventing future outbreaks will require addressing the conditions that lead to them.

"The doctors have said that the fever will subside. But I need to take care of prevention,” said mother Shampa Das. “Keep him away from where mosquitoes breed. But how is that even possible?”

A flower seller outside one of the many ancient temples at Cuttack in Odisha, Shampa explained that the slum she lived in was surrounded by open drains. The municipal authorities had come earlier in the year and “sprayed medicine” to kill mosquitoes. But an uncharacteristically late withdrawal of the monsoons, which experts have linked to climate change, has created new breeding sites.

By October 31, as per data from the NVBDCP, no deaths were recorded in Odisha as a result of dengue, even though there had been 2,296 reported cases – compared to 5,198 cases and five deaths due to dengue in all of 2018. But after uncharacteristic rains in Odisha linked to a late withdrawal of the monsoon, new breeding sites were created and cases persisted in November, with at least three deaths reported at SCB Medical College in the first week of November. Data for the entire month wasn’t available at the time of writing the story.

“It shows that you can’t be lax even for a bit," said the NVBDCP official from the Bhubaneshwar office. "We were hopeful that we would have a year with zero cases of dengue.”

Clogged drain near Cuttack Municipal Corp headquarters
A drain clogged with garbage, not far from the Cuttack Municipal Corporation headquarters. The state government has been implementing a Rs 810.83 crore project, funded by Jica, to build a comprehensive sewage system for the collection and disposal of wastewater for the first time in the city / Credit: Aniruddha Ghosal

Slums, like the one Shampa lives in, contribute the least to global emissions and are often the most vulnerable to the negative impacts of climate change. They tend to be built on low-lying land and are more vulnerable to flooding due to extreme weather events. They are also more vulnerable to extreme heat due to urban heat pockets within cities.

The impact of VBDs is no different. A study published earlier this year by researchers from Odisha’s capital Bhubaneshwar sought to go beyond the analysis of environmental and climatic risk factors driving dengue outbreaks and found a clear link between poverty and the disease. It found that the adjusted odds of having dengue were nearly three times higher for those whose jobs require long travel, the presence of breeding sites or a swampy area near their house. Those who stayed in thatched houses — linked to the lower socio-economic strata — were nearly three times more at risk, it added.

“People living with thatched houses may represent lower socio-economic strata compared to others. So, increased dengue from these houses could be because of the low protective measures in practice. Also, the housing characteristics such as windows, curtains, gardens and its relationship with dengue breeding sites cannot be ruled out,” the study said.

Back at the hospital, Shampa was preparing to head back to her home. She lives in a thatched house and travels a few hours for work every day – two factors that put her and her family at high risk for contracting dengue. The slum where she lives also has a dirty pond next to it and the drains are often clogged, overflowing.

“I will do what I can to try and protect my family, and my son,” she said resolutely.

This is Part 1 of a four-part series examining how climate change is impacting the spread of deadly diseases in India. The complete interactive package first appeared on News 18 on 30 Dec. 2019. Each piece was produced with the support of Internews’ Earth Journalism Network. Production and graphic visualization was done by Fazil Khan.

Banner image: Patients wait outside the Regional Diagnostic Centre's blood collection centre at the Sriram Chandra Bhanja (SCB) Medical College and Hospital. Odisha's efforts to tackle vector-borne diseases are often complicated by the pressure put on public health facilities / Credit: Aniruddha Ghosal


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