A viral pink eye epidemic, also known as conjunctivitis, is affecting hundreds of thousands of people in Pakistan. Over the past several months, as the country grapples with summer heatwaves and record rainfall, this contagious disease has been steadily spreading. Health authorities in Pakistan are facing significant challenges in containing this highly infectious pathogen, which appears to thrive in humid conditions.

Nearly 400,000 people in Pakistan have been infected with viral conjunctivitis, also known as pink eye, since the start of the year. The outbreak peaked last week, with over 10,000 cases reported in a single day in Punjab province on Saturday and 13,000 new cases reported on Tuesday.

Conjunctivitis is an inflammation of the conjunctiva, the mucous membrane that covers the front of the eye and eyelids. It can be caused by bacteria or viruses, and the current outbreak in Pakistan is thought to be caused by a highly contagious virus.

“Many different types of viruses can cause viral conjunctivitis (including the COVID-19 virus). However, the majority, up to 75 percent, of infectious conjunctivitis is caused by adenovirus,” Isabelle Jalbert, professor of optometry and vision science at UNSW Sydney, Australia, told Newsweek. “It appears that the outbreak in Pakistan involves a highly contagious form of the virus.”

According to The Telegraph, more than 56,000 schools in Pakistan closed their doors for four days amid an outbreak of viral conjunctivitis.

Paul Hunter, a professor of medicine at the University of East Anglia, said closures represent only a temporary solution and will not work long-term.

“I suspect that there are many more such outbreaks that are not reported,” he told the Telegraph.

“Closing schools may temporarily reduce the spread of adenoviruses, but transmission is likely to pick up again when the schools reopen.”