A Bordetella pertussis outbreak has been reported by the National Institute of Health (INS) of Colombia in the Kogui community, an indigenous group living in the Sierra Nevada de Santa Marta mountains in Northern Colombia, on March 18, 2022. They have remained isolated from the rest of the world since the Spanish conquest, rarely interacting with the modern world and not allowing outsiders inside their ancestral lands. The field investigation began on March 16, 2022 in different hospital centers in the city of Santa Marta, and identified a total of 17 hospitalized children from the Kogui indigenous community, 5 of them in the intensive care unit and 12 in a state of acute malnutrition. The samples analyzed by the INS National Reference Laboratory confirmed the detection of Bordetella pertussis through PCR; all infected children were unvaccinated.
Alfonso Torres Villafañe, indigenous leader and legal representative, reported further that 21 Kogui children have died from a respiratory condition since December 2021. “All the deceased children were between the age of 0 to 5 years. It is an unfortunate situation that children die and become ill from this disease. Secretaries, parents or guardian adults must commit to the vaccination of children under 5 years of age.”
Colombia’s routine pertussis immunization program includes a pentavalent vaccine, which contains DTP (whole cell pertussis component), HBV and Hib administered at 2, 4, and 6 months, with a booster of DTP given at 18 months and 5 years. Macrolide antibiotics (Azithromycin, Erythromycin and Clarithromycin) may prevent or mitigate clinical pertussis when given during the incubation period or the early catarrhal stage. When given during the paroxysmal phase of the disease, antimicrobial drugs do not change the clinical course, but may eliminate bacteria from the nasopharynx, and thus reduce transmission.
Azithromycin is most popular because it is given in a short, simple regimen of 1 dose each day for 5 days. It is the preferred antimicrobial for use in infants younger than 1 month of age. For infants younger than 1 month of age, macrolides should be used with caution: some studies have demonstrated an association between erythromycin and azithromycin with infantile hypertrophic pyloric stenosis (IHPS). However, infants younger than 1 month of age are at increased risk of developing severe pertussis and life-threatening complications. These risks outweigh the potential risk of IHPS that has been associated with macrolide use. Resistance of B. pertussis to macrolides is rare, and antimicrobial susceptibility testing is not routinely recommended.
Indigenous populations across the world share some commonalities including poorer health and socio-economic disadvantage compared with their non-indigenous counterparts. Generally, acute and chronic respiratory infections are more frequent and more severe in both indigenous children and adults.
Managing infection outbreaks in remote communities presents unique challenges such as limited health resources and delays with laboratory results. In rural settings where timely laboratory diagnosis is not possible, empiric treatment and isolation even in the catarrhal stage is essential to control the spread of pertussis. Chemoprophylaxis of high-risk contacts and prophylactic immunization of pregnant women and infants is important to protect those at highest risk of mortality. Collaboration between health professionals, patients, communities and governments is essential to reduce infections in indigenous populations and narrow this significant gap in social circumstances and health status.
By Dr. Simone Müschenborn-Koglin
Contributing Editor, GHP