How Karnataka’s Shivamogga Became the Hotbed of Monkey Fever

a group of people walking in the forest
The News Minute
Shivamogga, India
How Karnataka’s Shivamogga Became the Hotbed of Monkey Fever

The Shivamogga district that PK Rajagopalan had arrived to six decades ago, when he learnt of a “mysterious virus” there, was radically different from the one it is today. In March 1957, Rajagopalan was a 26-year-old, fresh-out-of-college field entomologist, who was called to investigate an outbreak of Yellow Fever-like disease in Kyasanur village in Shivamogga district of Karnataka. As casualties mounted, it soon became apparent that this wasn’t Yellow Fever, but a new kind of disease. It was named Kyasanur Forest Disease (KFD) – commonly known today as Monkey Fever. 

“The US-based Rockefeller Foundation was involved in setting up laboratories for the viral research. They set up a laboratory and field station in Sagar (a taluk in Shivamogga) to study this new disease and they were willing to spend a lot of money to find out how this disease had emerged and how it was being transmitted to humans,” said the now-92-year-old Rajagopalan over the phone to The News Minute.

It wasn’t easy for his team, however. They didn’t know what they were dealing with: Was it typhoid? Or perhaps a new type of Yellow Fever? Mosquitoes were the most likely vectors, it was thought. 

However, despite being vaccinated for Yellow Fever, the initial researchers started to contract the disease. Viral samples from the insect collectors in the team were sent to Rockefeller lab in New York for identification, says Rajagopalan. 

The lab confirmed the virus to be related to the one that causes Omsk hemorrhagic fever, which was discovered just a decade earlier in Siberia, Russia and was transmitted through tick bites. KFD was found to have been transmitted by ticks too. The question then arose: Did Shivamogga’s new disease come from Russia nearly 7,000km away? Could migratory birds have carried the ticks here? 

Rajagopalan and his team set about trapping birds – 8,474 of them across 184 species – and combing them for ticks. Hemaphysalis spinigera ticks, which are found across the Western Ghats, were found on 1,082 birds. “Ticks were found on passerine birds (ground-dwelling birds) and not on migratory birds. This showed that KFD was indigenous to the region,” said Rajagopalan, who manned the Sagar KFD research station between 1957 and 1970. 

man kneeling over paper


man walking through bush with white sheet


man kneeling over ground collecting bug with tweezers
PK Rajagopalan's team collecting ticks from Kyasanur Forest in the sixties / Credit: Special Arrangement. 

Around the time when Rajagopalan and his team were unraveling the mysteries of the disease, the Karnataka government was constructing the Linganamakki dam. The dam over the Sharavathi River in Shivamogga, built through the 1950s, would eventually displace nearly 22,698 families and submerge over 300 of prime forest land. 

Dr Rajagopalan believes the Sharavathi Hydroelectric Project may have accelerated the spread of the disease, which otherwise would have been contained within the dense forests. 

“It was a very thick evergreen forest with wild mammals that were natural hosts of tick species. The construction of the dam resulted in deforestation and wild animals migrated outwards. With that, ticks found an alternate host: the cattle,” said the scientist. 

A landscape of forest loss 

The changes around the newly built Linganamakki dam would soon cause a domino effect across the whole district. Families displaced by the dam were rehabilitated by Karnataka government officials on 13,067 acres of land in other parts of the Shivamogga district. Much of this was forest land, which was cleared out to accommodate the displaced families. Over the decades, as families expanded, more forest land was subsumed, often with local political patronage. 

“We were dumped here in lorries like cattle,” recalled Manjunath, a farmer from Purdaal village on the edge of Shettihalli Wildlife Sanctuary. His family was allowed to clear two acres of forest land in their new home, Purdaal, with the promise that they would be given land rights. “People had lost lands and they soon started cutting into forests to start farming. Eventually, their children expanded the cultivation (of areca and marigold) even more,” he said. 

Adalakoppa is on the tail end of the Sharavathi reservoir and was not on the list of villages that were acquired for the construction of the dam. The reservoir levels, however, rose to engulf the village farmlands. 

“The waters kept rising with the rains and it became impossible for my grandfather to cultivate there. The family eventually moved up the hills and cleared a small part of the forest to start afresh,” said Surendra Shetty, 33, who currently cultivates two acres that were cleared by his grandfather. 

Residents of nearly 40 households in the hamlet cleared forests uphill where they reside even now. Most households do not own title deeds for the lands. On paper, it is still considered forest land. 

“It really was a thick forest when we arrived here. There were a lot of animals around,” said Surendra’s mother Lakshmi (60). “But it wasn’t just us who changed the place. Even the forest department razed dense forests to plant acacia trees (fast-growing trees for timber),” she said. 

Research into KFD shows that regions that have experienced afforestation and replacement of natural forests with plantations were vulnerable to the spread of the disease. It was only a matter of time for Adalakoppa. In 2012, the inevitable happened: the first case of the disease was reported, after which monkey deaths were reported sporadically, showing the presence of the virus in the forests there. 

Shivamogga district has been a hotbed of landscape change, perhaps more than any other district in the southern Western Ghats. 

An Indian Institute of Science study, which looked at the satellite imagery between 1973 and 2018, found that the forest area in the region had declined by 9.79% or 83 of forests during this period. In its place, plantations – largely areca nut – have increased by nearly 20% or by an area of 1,648 sq. km. 

multicolored graph
Shivamogga lost of forests between 1973 and 2018, while plantations increased by 20%.
Source: “Insights of Forest Dynamics for the Regional Ecological Fragility Assessment”
by TV Ramachandra, Setturu Bharath, Aithal H Bharath.

“Landscape changes, particularly fragmentation of forests or replacing evergreen forests with plantations, are important factors for the spread of KFD in a region,” said Abi T Vanak, a senior fellow at the Ashoka Trust for Research in Ecology and the Environment (ATREE). He is also part of the Monkey Fever Risk Project that is researching socio-environmental factors that contribute to the spread of KFD in a region. 

The politics of land use change 

According to the Karnataka Public Land Corporation (KPLC), which is responsible for the protection of public lands, the Shivamogga district has 1.44 lakh acres of encroached lands – the highest among Western Ghat districts in Karnataka. KPLC data shows that just less than 2.75% of “encroached” lands in Shivamogga have been cleared. 

Nearly 1.33 lakh acres have been claimed by farmers, including those displaced by the Sharavathi Hydroelectric Project, under the government's Bagair Hukum schemes, which regularizes encroachments of lands based on certain terms. 

“Those who lost their lands due to the Sharavathi Hydroelectric Project should be given rights over their land, whether it is forest land or government revenue lands,” said environmental activist Akhilesh Chippalli. “However, what has happened now is that there is a culture, driven by political pressure, to encroach on forests or deemed forests, and then claim the land under this scheme,” he said. 

This was seconded by an official of the forest department, who said that any action to reclaim forest land inevitably leads to political backlash. “You’ll immediately see protests and receive calls from political representatives. It is a tricky issue here,” the official said. 

blue and white graph

Regularization of these lands has been a political issue in the district. Former Chief Ministers S Bangarappa and BS Yediyurappa and former Revenue Minister Kagodu Thimmappa have extended their support toward this. 

Earlier in March 2021, the Raitha (Farmer) Mahapanchayat, a large gathering of farmers took place in Shivamogga and passed a resolution demanding the regularization of Bagair Hukum lands. The meeting had been attended by farm leaders from the state and even Samyukt Kisan Morcha leader Rakesh Tikait, who had helmed the year-long protests against the Union government’s three controversial farm laws. 

“The claims around the Bagir Hukum scheme in the district are not true. People have been cultivating here for a long time and deserve land rights. Those who are landless deserve land to till and a site to build a house. There is enough land in the region that can be given to farmers. It is the forest department that destroyed forests, and farmers who have protected forests,” said TN Srinivas, the former head of the Shivamogga District Congress Committee and an associate of Thimmappa. 

The environmental changes and spread 

Signs of environmental degradation contributing to the spread of KFD in Shivamogga were even seen nearly 50 years ago. PK Rajagopalan’s mentor, Jorge Boshell-Manrique, a Colombian physician and epidemiologist who was instrumental in the eradication of Yellow Fever in South America, had spent five years in the research camp in Sagar from 1960. In a 1969 paper, he noted that the population in KFD-affected areas had doubled. “The consequent alterations of the ecosystem have produced a set of conditions favoring overt expression of a hidden enzootic process,” he wrote. 

Enzootic diseases are those that are endemic in animals and affect animals in closed ecosystems, such as dense forests. Repeated human contact here increases the chance of the virus jumping from animals to humans – with the virus causing a zoonotic disease, such as KFD or COVID-19. 

This “ripe” set of conditions seems to be occurring throughout the Western Ghats. Till 2012, Monkey Fever was found in five neighboring districts of Shivamogga, with the latter being the hub of the disease. In the past decade, however, it has been detected in Chamrajnagar district of southern Karnataka, the southern part of Maharashtra, Goa and Wayanad in Kerala, where cases are annually reported. 

But how was KFD detected in these states when they are not contiguous with the forests of Shivamogga, where KFD has seemingly found a permanent home? 

“It is an intriguing question and we have not yet figured out why. The ticks that carry the KFD virus are found across the Western Ghats. Perhaps the virus is not as prevalent there, or perhaps surveillance in other districts is not as strong,” says Dr Vanak. 

What is increasingly becoming clear is that environmental degradation seems to be driving the disease in these new places: deforestation, conversion of forests to cashew or areca plantations, and increased human habitation close to dense forests. 

map of regional area
graph of regional area
Source: Mourya, DT, Yadav, PD Recent Scenario of Emergence of Kyasanur Forest Disease in India
and Public Health Importance. Curr Trop Med Rep 3, 7–13 (2016).

The mystery of KFD remains unsolved 

PK Rajagopalan was transferred out of Sagar to Delhi in 1970 when his expertise was used for work on malaria control. His departure saw the field research station close. For the next few decades, research into the KFD virus stalled. 

“KFD is now a neglected tropical disease; it is no more a priority for the government or research institutions. (After the field station closed), there was only containment research and molecular research. We have lost two generations of active field research. There is a combination of factors that enabled this disease to become an epizootic in monkeys and an epidemic in man. What are these factors? Who wants to study them? Who wants to live in a forest, as I did for 13 years? Governments and research institutes do not care,” said Dr Rajagopalan. 

Even now, much of the protocols being used by the health department to tackle KFD stemmed from research done by Dr Rajagopalan and his team nearly 50 years ago. 

But things may have changed for the virus on the ground. A recent study by the National Institute of Virology (NIV), Pune showed that the KFD virus found in recent years had diverged by 2.76% in its genome structure compared to the early strains studied by Dr Rajagopalan and his team. The study postulates that this may have caused the rapid spread of the disease across the Western Ghats. It isn’t clear if the vaccine, which was developed using early strains, is effective against these mutations. 

Even health officials at Shivamogga have noted changes in how KFD manifests. “We are seeing a change in the kind of symptoms shown by KFD patients. Till about 2002, Hemorrhagic fever was the most common type of symptom. Now, you hardly find KFD patients with this symptom. The symptoms are more neurological,” says Dr SK Kiran, who oversaw KFD diagnosis and control in Karnataka for nearly a decade. 

After nearly four decades, a large consortium of research institutes across disciplines came together in 2016 to undertake the Monkey Fever Risk Project. A key component is to trace how the virus is transmitted between mammals and other carriers within forests. 

“With the current level of knowledge about the disease, KFD should not persist for such a long time in forests. The tick season is only between November and May. Where does the KFD virus go in the off-season? What is the role of small mammals? We hope to gain some insight into this,” said Dr Vanak, who is part of the project. 

For Dr Rajagopalan, these crucial gaps represent key knowledge gaps that need to be plugged with some urgency. For instance, he pointed out the role of bats in circulating the virus within forests. His own field research had isolated KFD from bats, but bats did not carry the ‘hard ticks’ that are conventionally thought to carry the KFD virus. “This is a major lacuna in our knowledge. Unless we know the source of the disease, we can’t manage its spread,” he said. Much more fieldwork was needed for KFD, he said. “It is a never-ending fascinating story.” 

This story was produced with the support of Internews’ Earth Journalism Network. It was originally published in The News Minute on2 December 2021 and has been lightly edited for length and clarity. 

Banner image: Much of the densely forested region of Shivamogga has been cleared for plantations, increasing the risk of zoonotic spillover / Credit: Vaidya via The News Minute. 

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