(UPDATE) ILOILO CITY: The local government unit (LGU) here has declared an outbreak of pertussis or whooping cough for the entire city on Monday.

The City Disaster Risk Reduction and Management Council declared the outbreak following recommendations from the city government's Health and Sanitation Cluster and the City Health Office (CHO).

The city government initially limited its recommendation to Jaro and Molo districts but this was later modified after Arevalo district logged a confirmed case of pertussis.

According to the CHO, there are seven confirmed cases of pertussis out of the 13 reported cases as of March 24.

Three of the six remaining cases have pending laboratory results.

Three cases of pertussis have been documented in Jaro district, three in Molo district and one in Arevalo district.

The CHO data showed that six of the confirmed cases are ages 1 to 3 months old and the other a 6-year-old.

Also on Monday, Mayor Jerry Treñas approved the recommendation of the city council to declare a state of calamity due to pertussis.

"After the declaration, we have an amount of P16 million for our response. A big portion of it will go to medicines and vaccines. If necessary, we will add more funds so we can buy more," Treñas said.

Dr. Roland Jay Fortuna, assistant department head of the CHO, said they are intensifying treatment to asymptomatic children who had close contacts with the infected patients by giving antibacterial prophylaxis.

He added that the CHO is also enhancing efforts for post-exposure vaccination for unimmunized or incompletely immunized children under 10 years old to curb the spread of the infection.

Fortuna said the city government currently has 525 vials of diphtheria and tetanus toxoids, which can provide protection against three bacterial infections: diphtheria, tetanus and pertussis.

"Our routine immunization is ongoing. We have available vaccines, and for those who have missed immunization, we are encouraging parents to immunize their children," he said.

Iloilo City is the first LGU in Western Visayas to declare an outbreak and the second in the entire country after Quezon City, which has declared a whooping cough outbreak on March 21.

Pertussis is a highly contagious respiratory infection transmitted through droplets from infected to susceptible individuals, such as infants and young children.Initial symptoms of the disease mimic those of a common cold, including a runny nose, fever, and mild cough.