Rheumatic fever and streptococci: the Wairoa College study

Area of Science:

• Medical Microbiology
• Epidemiology
• Public Health

Background:

• Rheumatic fever incidence is declining globally but not in New Zealand.
• Wairoa county exhibits exceptionally high hospital admission rates for rheumatic fever, five times the national average.
• High rates of beta-haemolytic streptococcus group A are prevalent in Wairoa.

Purpose of the Study:

• To investigate the high incidence of rheumatic fever in Wairoa, New Zealand.
• To identify factors associated with streptococcal infections and rheumatic fever prevalence.
• To determine the prevalence of rheumatic fever and rheumatic heart disease in Wairoa.

Main Methods:

• Cross-sectional survey including throat swabbing of secondary school students.
• Analysis of ASO titres and association with streptococcal infections.
• Prevalence study of rheumatic fever and rheumatic heart disease cases.

Main Results:

• 13.6% of subjects were positive for beta-haemolytic streptococcus group A.
• High ASO titres were associated with group A and C streptococci.
• Prevalence of rheumatic fever and rheumatic heart disease was 1.5% (11/715).
• Maori ethnicity was a significant discriminator for cases.

Conclusions:

• Rheumatic fever and rheumatic heart disease remain a significant public health issue in Wairoa.
• Ethnicity, specifically Maori ethnicity, is a key factor associated with rheumatic fever and rheumatic heart disease.
• Further targeted interventions are needed in high-risk populations.