EMBED >More News Videos Though a vaccination program has drastically reduced measles cases in the U.S., measles is still one of the leading causes of death in young children internationally, according to the World Health Organization.

Health officials in Montgomery and Galveston counties reported a case each of measles Monday, adding to three existing cases that were reported in northwest Harris County.According to Montgomery County officials, a 2-year-old girl is recovering from the disease. They also confirm to ABC13 Eyewitness News that this case is connected to one of the Harris County cases, but details of the connection were not immediately disclosed.Galveston County Health District also confirmed a case involving a boy whose age ranges from 12 to 24 months old. The child was tested on Jan. 28, and officials said the case is part of a cluster in the region.Earlier Monday, Harris County Public Health said two boys under the age of two and a 25 to 35-year-old woman were diagnosed with the measles. All three patients live in northwest Harris County.The city of Houston last reported a confirmed case of measles in Harris County in 2018.Measles is a highly contagious virus spread through direct contact or through the air.Symptoms include a high fever, coughing, runny nose and watery, red eyes between seven and 14 days after infection, the U.S. National Library of Medicine says.However, measles is preventable.Health officials are encouraging everyone to protect themselves from the virus by being vaccinated."You have a vaccine that can prevent the actual illness. Once you have it, the only thing you can do is to try to keep the fever down, keep them hydrated," said Dr. Suzanna Cruz at Baylor St. Luke's Medical Center.The Centers for Disease Control and Prevention says since the vaccine was approved in the 60s, measles cases have gone from three to four million a year to a 99 percent reduction, only to make a rebound, especially among pockets of those who aren't immunized.These latest cases in Texas come as other parts of the country battle an outbreak.