Diphtheria in Metro Manila, the Philippines 2006–2017: A Clinical, Molecular, and Spatial Characterization

Nobuo Saito, Virginia O. Dimapilis, Hiroshi Fujii, Motoi Suzuki, Elizabeth Freda O. Telan, Dorcas Valencia Umipig, Rontgene M. Solante, Alexis Q. Dimapilis, Ferdinand De Guzman, Eumelia P. Salva, Fumihito Nakayama, Kohei Toda, Chris Smith, Koya Ariyoshi, Christopher Parry

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

Background

Diphtheria is a vaccine-preventable disease that persists as a global health problem. An understanding of the pattern of disease is lacking in low- and middle-income countries such as the Philippines.

Methods

We conducted a retrospective review of the clinical, microbiological, and epidemiological features of patients admitted with a clinical diagnosis of diphtheria to an infectious disease referral hospital in Metro Manila, the Philippines, between 2006 and 2017. Cases were mapped and the distribution was compared with population density. Corynebacterium diphtheriae isolates from between 2015 and 2017 were examined by multilocus sequence typing (MLST).

Results

We studied 267 patients (range:12−54 cases/year) admitted between 2006 and 2017. The case fatality rate (CFR) was 43.8% (95% confidence interval, 37.8−50.0%). A higher number of cases and CFR was observed among children <10 years. Mortality was associated with a delayed admission to hospital and a lack of diphtheria antitoxin. Between 2015 and 2017 there were 42 laboratory-confirmed cases. We identified 6 multilocus sequence types (STs). ST-302 was the most common (17/34, 48.6%), followed by ST67 (7/34, 20%) and ST458 (5/34, 14%). Case mapping showed a wide distribution of diphtheria patients in Metro Manila. Higher case numbers were found in densely populated areas but with no apparent clustering of ST types.

Conclusions

Our analysis indicates that diphtheria remains endemic in Metro Manila and that the infection is frequently fatal in young children. Improved vaccine coverage and a sustainable supply of diphtheria antitoxin should be prioritized.

Original languageEnglish
Pages (from-to)61-68
Number of pages8
JournalClinical Infectious Diseases
Volume72
Issue number1
Early online date11 Mar 2020
DOIs
Publication statusPublished - 23 Jan 2021

Keywords

  • diphtheria
  • diphtheria antitoxin
  • MLST
  • the Philippines
  • vaccination

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