The mosquito virus chikungunya has left almost 500,000 people ill, and 109 of them are newborn babies, according to an official in the Dominican Republic hit by the disease.
The newborns contracted the illness from their mothers, who were ill while giving birth, Carmen Adames, the Health Ministry's coordinator dealing with the outbreak, told AP. None of the children have died, she added.
The symptoms of the disease take three to seven days to appear, and include high fever, severe headaches and joint pain that can render a person virtually immobile for months. Research in the Indian Ocean islands has demonstrated that patients can suffer joint pains for as long as two years, depending on their age.
There is no vaccine for the illness at the moment, and no specific cure as well; on the positive side, it has rarely been deadly.
Younger patients get well in about two weeks, while older patients may need a couple of months, and the elderly even longer.
The first locally transmitted case was recorded in late 2013, and the first cases of the virus reached the Dominican Republic in March 2014.
At least 1 million cases have been registered all over the hemisphere, according to the Pan American Health Organization.
In July, the Puerto-Rican government announced an epidemics of chikungunya, after 200 cases appeared in June.
Also in July, two people were infected on US territory – without having traveled abroad. It was the first time this has happened in the US since the discovery of the virus just over 60 years ago.