"Chlamydia will cause infections in healthy animals but if you have an immune-suppressed animal you would logically think it would get more infections and more disease, " he said.

Osterhaus said the findings, reported in the science journal Nature, did not exclude the possibility that chlamydia or other infections could increase the severity of the illness in some people.

Triple antibiotic ointment treats common bacterial eye infections, including chlamydia and conjunctivitis it comes in generic and name-brand products.