Mayor Martin Walsh and the Boston Public Health Commission (BPHC) today issued a health advisory after two young children in the city were diagnosed with meningococcal disease.

Both cases were associated with day care centers specializing in serving families experiencing homelessness, but it is not known if the two cases are connected, said officials.

Meningococcal disease is caused by a bacterial infection and is spread from person to person through saliva. The disease has become less common in recent years, with 10 to 15 cases reported statewide each year. There are several different forms of meningococcal disease, including infection of the blood and infection of the brain and spinal cord, known as meningitis. Early detection and initiation of antibiotics for suspected meningococcal disease is critically important.

There are safe and effective vaccines available to prevent infection from the most common forms of meningococcal disease and residents are encouraged to speak with their health care provider about vaccination options.

Any resident with questions about meningococcal disease can call BPHC at (617) 534-5611. Fact sheets are also available at bphc.org in English, Chinese, Haitian Creole, Portuguese, Spanish, Vietnamese.