The COVID-19 pandemic may be over, but our immune systems are still feeling the impact. After years of battling constant viral threats, from COVID-19 to seasonal flu and other infections, our body’s defense system is exhausted. Many people continue to experience lingering inflammation, frequent illnesses, and slower recovery times. This extended state of immune stress has compromised us further to chronic illness, including autoimmune diseases and even neurodegenerative diseases such as Parkinson's. So why is our immune system still in trouble? And how do we give it its power back? Understanding immune exhaustion is the beginning of rebuilding our body's natural immunity.

A weakened immune system makes people more susceptible to disease, mental illnesses, and even sleep disorders. Now, new research indicates that immune system depletion may play an important role in the onset of Parkinson's disease, a degenerative neurologic disorder that compromises movement and cognition.

Role of Inflammation in Parkinson's Disease

Dysfunctional immune response is a leading cause of long-standing inflammation within the body, that has been found to contribute towards a multitude of conditions, including cardiovascular conditions, diabetes, depression, and neurodegenerative diseases such as Alzheimer's.

As people age, their immune system naturally becomes less effective. This deterioration, referred to as immune exhaustion, may be a key contributor to the onset and progression of Parkinson’s disease. Rebecca Wallings, a Parkinson’s Foundation Launch Award grant recipient and senior postdoctoral fellow at the University of Florida, believes that an accumulation of exhausted immune cells could be driving neurodegeneration in Parkinson’s patients.

How a Tired Immune System Might Affect Parkinson's?

Parkinson's disease is most commonly linked with the degeneration and loss of dopaminergic neurons—motor nerve cells that produce dopamine, an essential neurotransmitter for movement. While researchers have long suspected inflammation is involved in this neurodegeneration, the mechanisms are not yet well understood.

Wallings' study is on immune cell exhaustion, a process by which aging immune cells fail to control immune responses effectively. Her research indicates that instead of dampening inflammation in Parkinson's patients, attempts should be made to rejuvenate the immune system to regain its functionality.

Energy Deficiency in Immune Cells

One of the major findings of Wallings' work is the function of mitochondrial impairment in immune cell exhaustion. Mitochondria are commonly called the powerhouses of cells, as they are vital for generating energy. As mitochondria age and become inefficient, immune cells fail to function well, potentially accelerating neurodegeneration in Parkinson's disease.

Wallings has found that mutations in the LRRK2 gene, a recognized genetic risk factor for Parkinson's disease, are linked with defective mitochondrial function and immune cell exhaustion. Her current work includes testing various therapeutic approaches to restore mitochondrial function in immune cells with the potential to enhance the immune system and potentially prevent or treat Parkinson's disease.

Will Rejuvenating the Immune System Help in Treatment?

For decades, the standard practice in treating Parkinson's has been to suppress brain inflammation. Yet Wallings' work indicates that instead of slowing down immune responses, restoring the immune system could be a more successful strategy. By addressing mitochondrial impairment and immune resilience, researchers can potentially reverse or slow down Parkinson's disease.

Wallings is now looking into how to rejuvenate immune cells by fixing mitochondria. She studies immune cells from patients with Parkinson's as well as from healthy subjects and performs experiments on animal models to determine if rejuvenation of the immune system could result in improved disease outcomes.

Lifestyle Factors That May Affect Parkinson's Risk

While there is no cure for Parkinson's disease, some lifestyle adjustments may decrease the chances of developing the illness. Since neurodegenerative diseases are associated with chronic inflammation and immune dysfunction, developing habits that enhance immune function might prove helpful.

Diet: There is evidence to suggest that eating in accordance with the Mediterranean or MIND diets, both high in antioxidants, healthy fats, and anti-inflammatory foods, can encourage brain wellness and reduce Parkinson's risk.

Avoiding Dangerous Substances: Restricting alcohol and nicotine use can maintain a robust immune system and suppress inflammation.

Reducing Stress: Chronic stress weakens immune function, so methods such as meditation, exercise, and sufficient sleep can lead to improved overall well-being.

India has a target to eliminate dog-mediated rabies by 2030. It has strengthened access to post-exposure prophylaxis for people exposed to rabid animals, but controlling transmission among dogs still remains a challengge.

India's National Action Plan for dog-mediated rabies elimination rests on human-health component, which focuses on post-exposure prophylaxis and awareness among bite victims, and the animal-health component, which focuses on vaccinating and sterilising stray dogs.

In a conversation with HealthandMe, Dr Hanul Thukral, Veterinary Epidemiologist, South Asia Field Epidemiology & Technology Network (SAFETYNET), formerly with the Centre for One Health, National Centre for Disease Control (NCDC), Ministry of Health & Family Welfare, Government of India, says that the human-health side of the programme is strong. The bigger challenge lies in giving the animal-health side enough resources, coordination and accountability.

The Gap Of Animal Health Component In Rabies

Dr Thukral talks about an unusual problem at the heart of India's rabies-control efforts. He speaks about the ownership of stray dogs and that they do not fall under any single ministry.

“Stray dogs also do not come under a particular ministry. They do not come under the animal husbandry ministry, the health ministry or the wildlife ministry. They are under the purview of local bodies, including municipal corporations and rural local bodies,” he said.

This is a larger issue as the animal-health component of rabies elimination depends on sustained vaccination and sterilisation campaigns. Dr Thukral said the country currently lacks dedicated funding and resources for this part of the effort.

For India to move faster towards the 2030 goal, he said local bodies need to be given greater financial and operational support, including resources to capture rabid dogs, sterilise stray dogs and vaccinate them.

He added, “There should be an incentive-based model for local bodies like Swachh Bharat. Financial or non-financial incentives could be offered to local bodies for their rabies efforts, including recognition for those that prevent the majority of deaths.”

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Treatment Is Available But The Patient May Seek Treatment Late

India's human-health response is strong. Dr Thukral said the health ministry has increased access to rabies vaccination and rabies immunoglobulins, with a goal of making vaccines available up to the PHC level and immunoglobulin available up to the CHC level.

Yet the first break in the prevention chain can occur before the health system even knows a bite has happened.

“The prevention chain breaks down where it actually starts. It starts with the awareness of dog-bite victims,” Dr Thukral said. “A person bitten by a dog has to recognise the danger and seek care before the health system can intervene. According to a recent estimate cited during the interview, only around 20-25% of dog-bite victims receive post-exposure prophylaxis, while 60-65% do not. Of those who receive it, only 50% complete it.”

Dr Thukral stressed that these are not definitive figures. “These are just estimates based on a subset of the population,” he said.

That gap can lead to delayed treatment. “In rabies, time is everything,” he said, adding, “If we don't get post-exposure prophylaxis immediately after the dog bite, after 10 hours or after 24 hours, it has virtually no use.”

The 70% Dog-Vaccination Challenge

Human treatment can prevent death after exposure, but elimination requires the transmission cycle to be interrupted among dogs. Around 70% vaccination coverage among dogs is needed to interrupt the transmission chain.

The problem, Dr Thukral said, is that India does not have reliable nationwide data showing what proportion of its stray-dog population is actually vaccinated.

He said, “A nationwide stray-dog census was only recently conducted, counting almost 1 crore 50 lakh stray dogs across the country. Local bodies and panchayats conduct surveys and organise vaccination campaigns within their jurisdictions, but the current effort is very scattered and very non-uniform.”

He added, “If I achieve 70% vaccination in a particular block, the dogs of that block are protected. But there is always a chance that unvaccinated dogs from the periphery or neighbouring blocks can enter that block.”

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Treatment Alone Can Prevent Deaths, But Not Eliminate Rabies

Dr Thukral says saving people from rabies and eliminating rabies are not the same goal. He said, “One estimate suggests that if India continues increasing post-exposure prophylaxis coverage while carrying out suboptimal dog vaccination, around 400 deaths could be prevented over the next 10 years.”

Another estimate cited by Dr Thukral puts the figure at about 400-500 deaths over the next 10 years, with spending about 5 to 10 crores. But preventing those deaths would still fall short of elimination. “That’s it. We cannot achieve elimination,” Dr Thukral said.

“Humans are not the source of the infection,” he explained. “In this case, dogs or other animals are the source of infection. Unless we target them, we do not move closer to elimination.”

India Does Not Have Reliable Data For Vaccinated Stray Dogs

The same data problem extends to the Animal Birth Control programme, which combines sterilisation with anti-rabies vaccination. The expert says that there is no nationwide figure showing how many stray dogs have been vaccinated or sterilised. The information exists, but it sits across individual municipal corporations and panchayats rather than in one comprehensive national dataset.

“Vaccinating stray dogs doesn't come under the purview of the health ministry or the animal husbandry ministry,” he said. That makes it difficult to answer a seemingly basic question: what proportion of India's stray dogs is vaccinated at any given time? “We do not have nationwide data,” Dr Thukral said.

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Reliable 'One Health' Approach

Rabies is not a problem that can be solved by hospitals alone. At the district level, Dr Thukral said an effective One Health system would require health departments, municipalities, animal husbandry authorities, veterinary services and welfare bodies to have clearly defined responsibilities, adequate resources and a mechanism to coordinate.

He said, “The health department would focus on post-exposure prophylaxis, animal-bite management and awareness. Local bodies would handle dog vaccination, sterilisation and solid-waste management. The animal husbandry department could provide technical support, while welfare bodies could promote responsible dog ownership. Let every department do its job and establish coordination among them.”

That coordination also becomes important after an individual bite. Municipal or animal-health authorities need to communicate with the health department because one reported bite may indicate that additional people have been exposed.

How To Recognise A Rabid Dog?

Another challenge is recognising rabid animals. Dr Thukral said that after a dog is bitten by another rabid dog, it can take up to three months for symptoms to develop. However, he stressed that this does not mean the animal transmits the virus throughout that entire period.

“It will transmit the virus about 10 days before it starts showing symptoms,” he said. He also described several behavioural and neurological changes that can raise concern.

A dog that suddenly becomes aggressive, unusually quiet, or behaves differently from its normal pattern may warrant attention. Other signs described by Dr Thukral include seizures, excessive drooling, and changes in vocalisation.

“The basic thing we need to look out for if we get a dog bite or exposure from a potentially rabid animal is, most importantly, change in the animal's behaviour,” he said.

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India’s Surveillance Gaps

India's surveillance recorded 54 rabies deaths in 2024, according to the Press Information Bureau. But an independent study cited during the discussion put the number at more than 5,700, and estimated that India may have between 3,000 and 7,000 deaths annually.

Dr Thukral said that India's human rabies surveillance system is well equipped to detect, diagnose and report suspected and confirmed cases. But the bigger vulnerability, he said, may occur before a suspected case enters the health system.

“If there are scattered cases, such as one bite or a couple of bites, unless that patient reports to a health facility for potential post-exposure prophylaxis, the health system will most probably fail to capture it,” he said.

In other words, surveillance can only record what comes into contact with the system. Community awareness and care-seeking behaviour therefore remain critical.

The Biggest Challenge In India’s Rabies Elimination Goal

Dr Thukral believes the health component of India's rabies programme is comparatively strong. Post-exposure prophylaxis is accessible, almost free and cost-effective, he said. But it becomes more difficult when the focus shifts to dogs.

“Sterilising and vaccinating a dog currently takes around Rs 1,500 per stray dog to vaccinate it and sterilise it,” he said.

With a stray-dog population of around 1.5 crores, the scale of resources required becomes enormous. According to Dr Thukral, local bodies generally do not have that kind of money to dedicate to rabies control.

“So, yes, our system is very much in place and very strong to detect human rabies cases and treat them and provide them with the necessary care,” Dr Thukral said. “But for elimination, we need to target the source of the infection, which is obviously these stray dogs.”

For India to reach its 2030 goal, he said, the pace needs to pick up in terms of resources, manpower and political intention.

India's rabies challenge is therefore not confined to what happens after a person is bitten. It begins much earlier. With awareness, timely care-seeking, dog vaccination, sterilisation, waste management, reliable data and coordination between agencies working across the human and animal-health systems.

The country can continue expanding access to post-exposure prophylaxis and prevent more deaths. But, as Dr Thukral emphasises, that alone cannot deliver elimination. The question for the next four years is whether India can move from responding to individual exposures to systematically interrupting transmission at its source. As the expert said, “We need to target the source.”

You can feel fine and still have a heart that is slowly changing. Researchers at Imperial College London and the MRC Laboratory of Medical Sciences say millions of people could be living with hidden inflammation that does exactly that. They say the changes can start years before any symptoms show up.

"Our study, which is the largest of its kind, suggests that millions of people could be living with hidden inflammation, which is slowly changing their heart and causing long-term damage," said Professor Declan O'Regan, British Heart Foundation Chair of Cardiovascular AI at Imperial College London.

What The Study Found

The study was published in the European Journal of Preventive Cardiology. The team looked at data from nearly 480,000 adults in the UK Biobank, a large health database, Imperial says. They measured a blood marker called glycoprotein acetyls, or GlycA for short, which the paper uses to measure chronic inflammation. They also used heart scans and genetic data.

People with the highest levels of inflammation, the top 20%, had a 43% higher risk of heart attack and stroke than those with the lowest levels, the bottom 20%, according to Imperial.

Imperial adds that higher levels also went with changes in the heart itself. These included thicker heart walls, smaller heart chambers and poorer filling of the heart. The researchers say such changes can build quietly for years before possibly leading to heart failure.

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Where The Inflammation Comes From

Chronic inflammation is a long-term, low-level activation of the immune system, Imperial explains. It has been linked to cancer and diabetes, and is increasingly seen as a driver of heart disease.

According to Imperial, higher inflammation was strongly linked to poorer social and economic circumstances and to mental distress, as well as to smoking and excess body fat.

"The surprising thing was how much social factors and mental health are linked to inflammation and damage to the heart, as well as more well-known risk factors like smoking and inactivity," O'Regan said. He added that there was also a strong genetic factor, "with some people being naturally more resilient or susceptible to the inflammatory damage that comes from different lifestyles."

What Could Come Next

The study named proteins from the interleukin-1 and TNF families as likely drivers of the damage, Imperial says. Several are already targeted by drugs in clinical trials, which Imperial says raises hopes that anti-inflammatory treatments could help prevent heart disease before symptoms begin. The researchers say combining inflammation blood tests with genetic risk scores could help find the people who would benefit most from early action.

There is earlier proof that this idea can work. In the 2017 Canakinumab Anti-inflammatory Thrombosis Outcomes Study, or CANTOS trial for short, led by Paul Ridker and published in the New England Journal of Medicine, 10,061 people who had already had a heart attack, and had high inflammation, were given canakinumab or a placebo. The paper concluded that at the 150 mg dose, given every three months, canakinumab led to fewer repeat cardiovascular events than the placebo, independent of any drop in cholesterol. But those were heart attack survivors, not people without symptoms.

What to keep in mind

The study reports links, and the researchers describe inflammation as one possible pathway to heart damage. They also stress that being genetically susceptible, or living in hard circumstances, does not mean a person will develop heart disease, and that much can be done to prevent long-term inflammation.

A few floaters, a brief flash of light or mild blurring across your vision may seem harmless at first. But when these changes appear suddenly without any probable cause, they may signal a bigger problem. On World Retina Day, experts explain when your retina needs urgent medical attention.

The retina is the light-sensitive layer at the back of the eye, which plays a crucial role in maintaining healthy eyesight. Some retinal conditions may develop without obvious symptoms in early stages, while others can present suddenly and threaten your eyesight if treatment is delayed.

“Retinal health is fundamental to maintaining clear vision and preserving quality of life, yet many retinal conditions can develop silently, without obvious warning signs in their early stages,” Dr Rajesh Kapoor, Medical Director, Suruchi Eye Hospital, Navi Mumbai told HealthandMe.

“By the time a person begins to notice blurred or distorted vision, dark spots, flashes, floaters, or other visual changes, the condition may already require urgent medical attention. This is why we need to shift our approach from waiting for symptoms to prioritizing awareness, regular comprehensive eye examinations and timely consultation with an ophthalmologist.”

What Are Floaters And Flashes?

Floaters can look like tiny dots, lines, specks or cobweb-like shapes moving across your field of vision. They are easier to notice when looking at a bright background.

Flashes, on the other hand, can look like brief streaks or bursts of light. They may occur even when there is no actual source of light around you.

Occasional floaters can occur for reasons that are not always serious. However, a sudden increase in floaters or the sudden appearance of flashes should not be dismissed, especially if there are other changes in vision. One of the conditions doctors want to rule out in such situations is retinal detachment.

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What Is Retinal Detachment?

“Retinal detachment is a serious condition which requires urgent medical attention and occurs when the retina, the light sensitive layer at the back of the eye pulls away from its normal position,” Dr Mudit Tyagi, Scientific Chair, VRSI and Head, Smt Kanuri Santhamma Center for VitreoRetinal Diseases, L V Prasad Eye Institute, Hyderabad told HealthandMe.

There are several possible causes of retinal detachment. According to Dr. Tyagi, they include injury to the eye, high myopia and certain eye diseases.

When the retina separates from its normal position, its ability to function properly can be affected. The longer the condition remains untreated, the greater the concern about permanent vision loss.

Sudden Flashes And A Curtain Or Shadow Over Your Vision

The symptoms of retinal detachment can vary, but certain changes should warrant immediate medical attention.

A dark curtain or shadow across the field of vision is concerning because it can represent a portion of the visual field being lost.

Dr. Tyagi said, “The urgency of recognising retinal detachment can’t be overstated. If you have sudden flashes of light, a dramatic increase in floaters, or a dark shadow or curtain across your field of vision, don’t ignore it, even if there is no pain.”

The absence of pain should not be misconstrued as a non-emergency. A retinal problem can occur without the kind of discomfort people usually associate with an eye emergency.

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Timing Is Key

Retinal detachment is not a condition where it is advisable to wait and see whether symptoms settle on their own. “Retinal detachments, if detected in time and operated early enough can result in a good recovery of vision,” Dr Tyagi said.

He added, “It is important, therefore, to be vigilant and see an eye care specialist as early treatment can help avoid preventable loss of vision. So, timely recognition and diagnosis followed by right treatment can help save vision.”

This is why sudden visual changes deserve attention even if they seem minor initially.

Who Is At Risk?

Some people may need to be particularly proactive about retinal health. Dr. Kapoor said individuals with diabetes, increasing age, a family history of retinal disease or other risk factors that may affect retinal health should be more careful and alert.

Diabetes can affect the blood vessels supplying the retina and lead to diabetic retinal disease. Regular eye examinations can help identify changes before vision is significantly affected. Dr Kapoor also stressed that screening should not necessarily wait until symptoms appear.

“Advances in retinal imaging, diagnostics and treatment today provide ophthalmologists with valuable opportunities to identify and manage several retinal conditions at an earlier stage. However, technology can make its greatest impact when people seek eye care at the right time.”

A sudden change in vision does not automatically mean that a person has retinal detachment. But because some retinal conditions can progress rapidly, it is important to have sudden symptoms assessed rather than trying to determine their cause on your own.

Dr Kapoor said: “Through greater public awareness and proactive screening, we can encourage people to take retinal health more seriously. Protecting sight begins with understanding that healthy vision should never be taken for granted—because when it comes to the retina, we should not wait for a problem to become noticeable before taking action.”