India has seen a concerning rise in infectious diseases this year, according to new data from the Indian Council of Medical Research (ICMR). The latest report from ICMR’s Virus Research and Diagnostic Laboratories (VRDL) network found that pathogens were detected in 11.1 per cent of the 4.5 lakh patients tested across the country between January and June 2025.
Top infections detected across India
The top five infections detected included Influenza A (in respiratory illness cases), dengue virus (in fever and haemorrhagic cases), Hepatitis A (in jaundice cases), Norovirus (in diarrhoeal outbreaks), and Herpes simplex virus (HSV) (in acute encephalitis cases).
What the key pathogens mean
Influenza A:
According to the Centers for Disease Control and Prevention (CDC), Influenza A causes respiratory illness ranging from mild cold-like symptoms to pneumonia. It mutates rapidly and can trigger pandemics, making annual flu shots vital for protection.
Dengue:
As per the World Health Organization (WHO), dengue is a mosquito-borne viral infection causing high fever, rashes, and joint pain. Severe cases can lead to internal bleeding or shock. Preventing mosquito breeding is the best defence.
Hepatitis A:
According to WHO, Hepatitis A spreads through contaminated food or water and affects the liver. Most people recover fully, and the infection can be prevented through vaccination and better sanitation.
Norovirus:
The CDC says Norovirus is extremely contagious and often linked to foodborne outbreaks. It causes vomiting and diarrhoea, spreading easily in crowded places. Hand hygiene and food safety are key to prevention.
Herpes Simplex Virus (HSV):
According to WHO, HSV types 1 and 2 cause oral and genital sores. The virus remains in the body for life, but antiviral treatment helps control symptoms and reduces transmission.
Between January and March, 10.7 per cent of samples tested were positive for pathogens. This number rose to 11.5 per cent between April and June, marking a 0.8 percentage point increase.
Experts warn against ignoring small spikes
While the rise may appear small, experts caution that it shouldn’t be overlooked. “A small rise in infection rates should not be ignored. It’s a reminder to stay alert for seasonal diseases and new viral threats,” a senior ICMR scientist said. “If we continue tracking these patterns closely, we can prevent future epidemics before they spread.”
The report shows that monitoring quarterly changes in infection rates helps detect early warning signs of outbreaks, giving public health authorities time to respond.
191 disease clusters investigated in three months
The VRDL network, which functions as India’s early warning system for viral outbreaks, investigated hundreds of disease clusters this year. Between April and June 2025, it examined 191 clusters, identifying infections such as mumps, measles, rubella, dengue, chikungunya, rotavirus, norovirus, and Epstein-Barr virus (EBV).
Earlier, between January and March, 389 disease clusters were investigated, with common infections including hepatitis, influenza, leptospirosis, and sexually transmitted infections (STIs) among others.
India’s virus surveillance network expands rapidly
Since its establishment in 2014, the VRDL network has expanded from 27 laboratories to 165 across 31 states and union territories. In the last decade, more than 40 lakh samples have been tested, with pathogens identified in 18.8 per cent of cases. So far, over 2,500 disease clusters have been detected nationwide.