‘Mystery’ Diseases: A Tale Of Pathogens & Persistence

“Door-to-door visits to every household helped to identify others who were sick, and they were all started on symptomatic treatment,” Jayesh Katira, deputy director, epidemic in Gujarat’s health department, told IndiaSpend.

But the authorities struggled to name the disease, prompting the media to report the outbreak as a “mystery” disease (see here and here).

“When the causative organism or agent of a disease, and its mode of transmission from one person to another hasn’t been identified, lay people and the media tend to label it ‘mysterious’,” said Anil Kumar, principal advisor, National Centre for Disease Control, and president, Indian Association of Epidemiologists.

Back in Kachchh, samples drawn from the patients were sent for testing to the National Institute of Virology in Pune.

“When we face an unknown disease, we test for diseases that have recently been seen in different parts of the country as well as for seasonal diseases that may have just emerged,” Katira explained.

Tests for the Nipah virus, the Hantavirus, Crimean Congo haemorrhagic fever and other viral infections occurring in humans all came negative, and so did the zoonotic link. Essentially, the samples were also tested for diseases originating in cattle.

However, “microbiology tests showed that a single patient was infected by various types of bacteria, which we believe worsened a simple viral infection,” added Katira. So, “we attributed the deaths to an airborne respiratory infection.”

Daily surveillance and treatment helped contain the outbreak, with two more people succumbing in the ensuing week. The Kachchh experience suggests that an outbreak of disease, no matter how virulent, can be brought under control with the right intervention.

“Epidemiologists don’t call diseases ‘mysterious’, because the cause of occurrence and channel of transmission can always be identified with careful investigation,” said Kumar.

Sometimes, he agreed, “the environment can cause the causative agent to undergo some change, in which case the investigation can take time.” The term ‘mysterious’ suggests that the disease cannot be figured out or controlled, which is not the case. Kumar recommends the scientific terminology: “an illness of unknown aetiology”.

Pathogen combinations have made diseases hard to identify

The combination of a virus and bacteria made it more challenging to identify the cause of disease in Kachchh. A mix of pathogens was also confirmed to be behind the outbreak of disease in the Democratic Republic of Congo in 2024.

In early December, the World Health Organization (WHO) had reported the outbreak of disease in Panzi, a remote region in the country’s Kwango province. More than 400 people had taken ill, with fever, headache, cough, weakness and a runny nose. Thirty-one patients had succumbed to the disease, which at the time, was considered “undiagnosed”.

A WHO update on December 27 said that laboratory tests suggested “a combination of common and seasonal viral respiratory infections and falciparum malaria, compounded by acute malnutrition” had caused the severe infections and deaths, “disproportionally affecting children under five years of age.”

Kumar explained that “it is possible that combinations of various bacteria/viruses and agent hosts and environmental factors lead to atypical presentation cases and outbreaks”.

However, he emphasised that “a careful high quality epidemiological investigation using advanced tools and technology can determine the channel of transmission and precipitating factors leading to the outbreak.”

Comorbidities increase vulnerability to acute diseases

According to the WHO, underlying malnutrition is believed to have compounded the severity of illness in Panzi, the Democratic Republic of Congo. In Kachchh, Katira pointed out that the affected area is mostly inhabited by a cattle-rearing community. “Due to the inclement weather, they would have faced some hardship, and may also have skipped meals, due to which their immunity may have been compromised.”

Of the 17 deaths in Kachchh, at least two occurred due to myocardial infarction (or heart attack) and one person also had cancer, Katira said. Essentially, “the presence of non-communicable diseases also lowers immunity.”

In Chhattisgarh’s Sukma district, where seven deaths were reported to have occurred due to an ‘unknown’ disease in October 2024, the chief medical & health officer Kapil Dev Kashyap clarified that the deceased had suffered from severe diarrhoea. There too, a couple of the fatalities were elderly and had comorbidities (diabetes and hypertension).

Rainfall exacerbates the outbreak of disease

Rainfall prior to the outbreak of disease was a common factor in Kachchh, Sukma and in the Congo.

In the early days of September 2024, Kachchh saw heavy rainfall events, a factor that Katira associates with the easier transmission of viruses. While viruses are always present in the environment, Katira explained, high humidity and rain are ripe conditions for their spread.

In fact, in Panzi, the high number of cases of fever and other symptoms was not considered an aberration in view of the onset of the rainy season. What stood out was the high number of fatalities.

The residents of Chitalnar village in Sukma had developed severe diarrhoea after inclement weather.

“The people drink raw river water, and the area had seen heavy rainfall prior to the loss of life,” Kashyap told IndiaSpend. “They had contracted a water-borne infection.”

Poor infrastructure in rural India can increase disease fatalities

Kachchh and other parts of west Gujarat saw 75% more than normal rainfall during the 2024 monsoon season, a factor that could predispose the area to disease outbreaks.

Heavy rain creates particularly challenging conditions for those living in kuccha homes. Heavy rain also cuts off access to health services for many people.

“People were cut off, making early diagnosis and treatment difficult,” Katira told IndiaSpend, of residents of the affected villages.

Liaqat Ali, a member of the panchayat of Lakhpat, a village located about 45 km away from the affected area, told IndiaSpend that their approach roads to the nearest community health centre in Dayapar, which services the area, would have been inundated.

“Roads in this area are very bad at the best of times; during heavy rainfall the situation deteriorates,” said Ali.

Ali also pointed out that the community health centre was understaffed, with just three of seven posts filled, and that conditions that should have been manageable in it--such as a pregnancy with some complications--were referred out.

“Provisioning health services in rural India is a challenge,” said Kashyap, speaking in context of Sukma district, where he is posted. “We have 20-30 villages where we have no health workers, we have been unable to identify the right people to employ and train.”

Health workers are the most basic rung in the public health infrastructure, followed by sub-centres, primary health centres and community health centres. India had 167,275 sub-centres, 26,636 primary health centres and 6,155 community health centres, as of June 2024. In recognition of the ‘time to care’, or the time taken to reach a care centre, the government has mandated that every habitation in a challenging terrain should have a sub-centre within a 30-minute walk. However, the skills of the staff also need to be addressed.

When 38 people from related families fell sick in village Badhal, in Rajouri district, Jammu & Kashmir, in early December 2024, they sought health services but still, 17 succumbed over the next six weeks--once again, supposedly of a “mystery” disease.

While the sickness started after a marriage in the family, the sarpanch of Badhal Mohammed Farooq told IndiaSpend that he didn’t attribute the sickness nor the deaths to anything consumed at the event because “neighbours and others who attended the marriage should have fallen sick too”.

News reports cited cadmium toxicity as the reason for the sickness and deaths.

IndiaSpend reached out to the chief medical & health officer of Rajouri, Manohar Lal Rana, the state surveillance officer for Jammu Division Harjeet Rai, and the senior superintendent of police, Rajouri, Gaurav Sikarwar, to understand how such toxicity might have developed, what sort of exposure might the community have had, and over how much time would the disease have developed. They declined to comment, saying the matter was still under investigation.

Teams from many reputed hospitals across the country have visited the area to investigate the cause of disease. A source in the know, who did not want to be named as he was not authorised to speak to the media, made this interesting statement: “Now if people in the affected area develop the same symptoms, no one will die.”

The source indicated that “when the first few people fell sick, the caregivers were clueless. They had never seen anything like it so they had no precedent to follow.”

“It is only after losing so many victims and having so many expert medical teams visit the area and share their opinion, that the local health staff would be able to treat a patient with similar symptoms,” said the source.

Essentially, health professionals in basic health centres lack the experience to treat many diseases.

Low acceptance of modern medicine still a concern in rural India

Sometimes, patients’ socio-cultural beliefs and lack of awareness pose obstacles to their timely treatment.

Chitalnar, in Sukma, lies about 4 km away from a sub-centre, and about 10 km away from the nearest doctor stationed in the primary health centre in Pushpal. But when its residents fell sick, they first visited faith healers, according to Kashyap. “During that time, their condition worsened, they developed dehydration.”

After word got out, the authorities quickly created a mini hospital in a room in the village, where many of the sick were treated, and they also distributed oral rehydration solutions. However, the delay in accessing health services proved fatal for a few of those who had first fallen sick. Kashyap said a couple of the deaths had occurred in the district hospital, two had occurred in transit when the patients were being taken to the hospital, and a couple of patients had died at home.

A similar situation arose in Udaipur district’s Kotra block, where 17 children were reported to have died of a mystery disease over 30 days in October 2024. Kotra is predominantly populated by tribal people, who live in far-flung scattered villages. Ghata, one of the affected villages, has a doctor but people delayed seeking medical assistance for their children, panchayat member Lasma Ram told IndiaSpend.

Lasma Ram attributed the deaths to “seasonal diseases” and “mosquito bites”.

After word got out about the deaths, the investigating team constituted by the district health authority conducted door-to-door health screening and found several confirmed cases of malaria. Possibly, the children who died may also have succumbed to malaria.

“The health department had no medical reports or other documents to rely on, and so could not confirm the cause of mortality,” Udaipur district’s chief medical and health officer Ashok Aditya told IndiaSpend.

No disease is too complicated to explain to the public

Confirming the cause of mortality is tricky sometimes. Still, experts caution against mislabelling outbreaks.

“We must steer clear of labelling any diseases as ‘mysterious’ or too complicated to explain to the public,” Jayaprakash Muliyil, epidemiologist and consultant, Department of GI Sciences, Christian Medical College, Vellore, told IndiaSpend. “There is always a cause of disease, and India has sufficient trained epidemiologists to identify diseases.”

Muliyil stressed the need to share scientific information with people “in the interests of public health, even if it means informing people that the diagnosis of a disease is still a work in progress”.

He also noted that “there is a tendency to mask diseases to suppress information, or under-report deaths, sometimes for political reasons, which is counter-productive to public health”. Suppressing information only enhances rumours and gives rise to anxiety.

Lapses in public health communication stood out quite starkly during the Covid-19 pandemic, the lessons behind those lapses have yet to be fully assimilated in the public health response to disease outbreaks, said Abhay Shukla, national co-convenor, People’s Health Movement.

Citing the 5 Ts of public health communication--Transparency, Trust, Timeliness, Truthfulness and Two-way exchange--Shukla explained that in about 10% of outbreaks, the cause may initially not be clear at local level and remains so for some time. But even then, “whatever is known should be conveyed to the people.”

“Even letting people know the status of the investigation is helpful, the communication lines must be kept open,” said Shukla.

Trust is trickier because it isn’t built in a day. Trust in health systems is an outcome of successive good experiences with a health service point. However, it is a reflection of the gaps in health services--especially in remote regions--that people sometimes don’t sufficiently trust the health system to accept special measures during emergencies, said Shukla. “People aren’t passive objects, they must be made partners in the control of outbreaks. But this requires building trust in the system and responding actively to people's queries.”

“Messaging must be timely and regular,” added Shukla. “Silences generate rumours and negative emotions. The messaging must also be realistic, and based on the actual ground situation, and create channels for people to clarify their doubts.”

Back in Badhal, everyone knows that high-level teams from various big institutions have investigated the deaths. But the sarpanch Farooq lamented, “we still don’t know the cause, and so, we remain fearful.”

“People no longer celebrate events together,” said Farooq. “Nor do they want to eat or drink anything in each other’s homes. Everyone thinks their family could suffer the same fate. If you get to know [the cause of the disease], please let us know too.”

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