Itching, burning, stinging and bulging blood vessels – these highly contagious conjunctivitis, or “red eye”, symptoms are spreading rapidly in Cambodia, where ophthalmologists say the outbreak is the worst in recent memory.

“We’re seeing about five times more patients than usual,” Dr Do Seiha, vice-chairman of the Cambodian Ophthalmology Society and vice-director of the National Program for Eye Health, said. “We see outbreaks during the rainy season every year, but the number of patients is much higher this year than in the past.”

In a report released last week, the National Program for Eye Health found that 4,089 patients sought hospital treatment for conjunctivitis over a period of four weeks.

Hospitals and eye health centres in Phnom Penh, Battambang, Kandal and Kampong Cham saw the greatest proportion of infected patients.

“The number doesn’t include all the patients because not everyone will come to a doctor when they get the infection,” Seiha said.

Conjunctivitis is caused by the adenovirus and is transmitted person to person through the exchange of respiratory particles.

Shaking hands, sharing towels or touching the same surface as an infected person can lead to transmission.

“Usually people get better in one to two weeks and we treat to relieve the symptoms with things like anti-inflammatory eye drops,” Dr Ngy Meng, director of the National Program for Eye Health and director of the Khmer-Soviet Friendship Hospital, said. “The most important thing is for patients to be careful of their hygiene; they need to wash their hands with soap every two hours and watch what they touch.”

Doctors advise patients to stay home from work, and say children infected with the virus should be kept home.

“Every age group can be affected, but it spreads especially quickly in schools, where children play together and touch everything,” Meng said.

Ophthalmologists say the jury’s still out on whether flooding is the culprit behind the hike in cases this year.

“Maybe it’s because of the flooding or more rain this year, but we really don’t know,” Seiha said.