A surge in rare and deadly brain infections emerged as one of the most serious public health challenges of 2025. Kerala’s deadly brain eating amoeba outbreak shook the state with 170 cases and 42 fatalities in 2025 alone, the government informed the Parliament.
In many parts of the country, Japanese encephalitis cases rose, fuelled by climate change, poor mosquito control and low vaccination coverage. The rise in these infections reflects an urgent need for healthcare system to evolve in order to fight the diseases better and lower fatality rate. As the year draws to a close, let’s look back at the brain infections that made news this year.
Kerala’s brain-eating amoeba outbreak
Brain-eating amoeba cases in Kerala wreaked havoc this year. While the survival rate has over the years improved as per a BBC report, number of cases are rising rapidly.
Naegleria fowleri are known to thrive in warm freshwater lakes, ponds and rivers, according to CDC. Infection spreads when the contaminated water enters the body through nose and reaches the brain, wherein it causes swelling and tissue destruction. The symptoms are harmless to begin with resembling flu-like symptoms such as high fever and intense headache, however in advanced states, seizures or weakness on one side of the body is observed.
Dr. Jayesh Sardhara, Director – Minimally Invasive Brain & Spine Surgery, Fortis Hospitals Mumbai told Financial Express.com that Kerala’s surge in brain infections during 2025 represents one of the most significant neurological health crises in recent memory.
“The state reported 170 cases of amoebic meningoencephalitis with 42 deaths in 2025 alone, compared to just 2 cases and 2 deaths in 2023. This 85-fold increase in incidence demands critical examination of underlying causative factors and healthcare system preparedness,” he added.
Shedding light on the fatal brain condition, Dr. Sadique Pathan, Neurologist, Sahyadri Super Speciality Hospital, Hadapsar, Pune, told Financial Express.com that the infection leads to a brain condition called primary amoebic meningoencephalitis (PAM), which can progress quickly and be fatal if not treated right away. “The rise in cases has raised concerns about water safety, particularly in areas with high temperatures and still water bodies,” the expert said.
Dr Sardhara says what differentiates the 2025 outbreak from previous years is the changing epidemiological pattern.
“Unlike earlier outbreaks where cases clustered around single water sources, the 2025 cases emerged as isolated incidents from across the state. This geographic dispersion suggests broader environmental contamination and potentially increased human exposure to contaminated water sources, complicating both epidemiological investigations and preventive interventions,” the expert adds.
Japanese Encephalitis cases rose across 11 states in India
The phenomenon of global warming is leading to surge in mosquito-borne diseases in India and across the world. A study published in Acta Tropica, a peer-reviewed journal finds out that climate change could create favorable mosquito breeding habitats, make the temperature suitable for mosquito development and abundance, increase the geographic distribution of mosquitoes, and increase mosquito-to-host contact or exposures in temperate regions.
This year, Assam reported as many as 26 fatalities, due to Japanese Encephalitis. The threat may further if sufficient people are not vaccinated.
“Japanese encephalitis has been resurfacing across parts of India and Nepal, adding another layer of strain. Together, they’ve created a sense that the infectious landscape is shifting faster than we’re used to,” Dr Suyog Doshi, consultant, Neurologist, Apollo Hospitals Pune told Financial Express.com.
“India reported 224 confirmed cases of Japanese Encephalitis across 11 states as of August 2025. The seasonal pattern of these infections, occurring during monsoon and post-monsoon periods, creates predictable yet challenging scenarios for healthcare systems already strained by resource limitations,” says Dr Sardhara.
“The biggest jump has come from PAM. Alongside that, Japanese encephalitis has seen a steady rise, particularly after heavier monsoon patterns. We’ve also continued to manage a mix of other encephalitic illnesses, herpes, enteroviruses, and mosquito-borne viruses, which haven’t disappeared but feel more visible because of better testing,” says Apollo Hospital’s Dr Doshi.
Other brain infections that grabbed headlines in 2025
“The brain-eating amoeba Naegleria fowleri, Japanese encephalitis (JE), herpes simplex virus (HSV) encephalitis, tuberculous meningitis, cerebral malaria associated with malaria, and mumps encephalitis were among the many brain infections that increased in 2025,” says Dr Pathan.
“More cases of HSV reactivation in immunodeficient individuals have led to an increase in HSV encephalitis. Mumps encephalitis has become more prevalent as a result of vaccination gaps, and tuberculous meningitis and malaria-related cerebral malaria have increased, especially in regions with high tuberculosis and malaria burdens,” adds the expert.
Common symptoms of brain infections in 2025
Across these infections, the early warning signs look strikingly similar, high fever, intense headache, and stiff neck are the usual starting points. Many patients become unusually drowsy or confused, which is often when families rush them to us. In more advanced stages, seizures or weakness on one side of the body can appear. What’s most challenging is how quickly some infections, especially PAM, can escalate, sometimes within a day or two, says Dr Doshi.
Disclaimer: Always consult a doctor before starting any diet or fitness routine. Always seek the advice of your doctor with any questions about a medical condition.
