DHAKA, Bangladesh

Dengue fever, a virus spread by mosquitos, has infected stateless Rohingya refugees in one of the world's largest and most congested refugee camps in Cox's Bazar, Bangladesh's southeastern coastal district. Health experts say these camps have become a breeding ground for dengue mosquitos that are different from ordinary mosquitoes in both shape and color.

Bangladesh is currently hosting about 1.2 million Rohingya, the majority of whom fled a brutal military crackdown in Myanmar's Rakhine state in August 2017.

An average of seven to eight people live in a 120-square-foot room in a house with a poor sewer system, making the camp a breeding ground for mosquitos, particularly those carrying the dengue virus.

Dengue fever outbreaks are common during the rainy season in many places across the country, notably Dhaka and Cox's Bazar, due to humid conditions.