Incidence of acute rheumatic fever in northern and western Uganda: a prospective, population-based study

BACKGROUND

Acute rheumatic fever is infrequently diagnosed in sub-Saharan African countries despite the high prevalence of rheumatic heart disease. We aimed to determine the incidence of acute rheumatic fever in northern and western Uganda.

METHODS

For our prospective epidemiological study, we established acute rheumatic fever clinics at two regional hospitals in the north (Lira district) and west (Mbarara district) of Uganda and instituted a comprehensive acute rheumatic fever health messaging campaign. Communities and health-care workers were encouraged to refer children aged 3-17 years, with suspected acute rheumatic fever, for a definitive diagnosis using the Jones Criteria. Children were referred if they presented with any of the following: (1) history of fever within the past 48 h in combination with any joint complaint, (2) suspicion of acute rheumatic carditis, or (3) suspicion of chorea. We excluded children with a confirmed alternative diagnosis. We estimated incidence rates among children aged 5-14 years and characterised clinical features of definite and possible acute rheumatic fever cases.

FINDINGS

Data were collected between Jan 17, 2018, and Dec 30, 2018, in Lira district and between June 5, 2019, and Feb 28, 2020, in Mbarara district. Of 1075 children referred for evaluation, 410 (38%) met the inclusion criteria; of these, 90 (22%) had definite acute rheumatic fever, 82 (20·0%) had possible acute rheumatic fever, and 24 (6%) had rheumatic heart disease without evidence of acute rheumatic fever. Additionally, 108 (26%) children had confirmed alternative diagnoses and 106 (26%) had an unknown alternative diagnosis. We estimated the incidence of definite acute rheumatic fever among children aged 5-14 years as 25 cases (95% CI 13·7-30·3) per 100 000 person-years in Lira district (north) and 13 cases (7·1-21·0) per 100 000 person-years in Mbarara district (west).

INTERPRETATION

To the best of our knowledge, this is the first population-based study to estimate the incidence of acute rheumatic fever in sub-Saharan Africa. Given the known rheumatic heart disease burden, it is likely that only a proportion of children with acute rheumatic fever were diagnosed. These data dispel the long-held hypothesis that the condition does not exist in sub-Saharan Africa and compel investment in improving prevention, recognition, and diagnosis of acute rheumatic fever.

FUNDING

American Heart Association Children's Strategically Focused Research Network Grant, THRiVE-2, General Electric, and Cincinnati Children's Heart Institute Research Core.

Previous Traditional Medicine Use for Sore Throat among Children Evaluated for Rheumatic Fever in Northern Uganda

Timely diagnosis of group A streptococcal (GAS) sore throat coupled with appropriate antibiotic treatment is necessary to prevent serious post-streptococcal complications, including rheumatic fever (RF) and rheumatic heart disease (RHD). Traditional medicine (TM) is a known common adjunct to formal medical care in sub-Saharan Africa. A better understanding of health-seeking behavior for sore throat both within and outside the formal medical system is critical to improving primary prevention efforts of RF and RHD. A prospective mixed-methods study on the use of TM for sore throat was embedded within a larger epidemiological study of RF in Northern Uganda. Children presenting with symptoms of RF were interviewed about recent TM use as well as health services use for sore throat. One hundred children with a median age of 10 years (interquartile range: 6.8-13 years) completed the TM interview with their parent/guardian as part of a research study of RF. Seventeen, or 17%, accessed a TM provider for sore throat as part of the current illness, and 70% accessed TM for sore throat in the past (73% current or past use). Of the 20 parents who witnessed the TM visit, 100% reported use of crude tonsillectomy. Penicillin was the most frequently prescribed medication by TM providers in 52% of participants who were seen by a TM provider. The use of TM among children presenting with symptoms of sore throat in northern Uganda is common and frequently used in tandem with diagnostic services offered through the formal healthcare system. Engagement with TM practitioners may provide an important avenue for designing effective primary prevention and management strategies of RF and reduce the global burden of RHD.

Cross-sectional study of population-specific streptococcal antibody titres in Uganda

OBJECTIVE

Despite substantial variation of streptococcal antibody titres among global populations, there is no data on normal values in sub-Saharan Africa. The objective of this study was to establish normal values for antistreptolysin O (ASO) and antideoxyribonuclease B (ADB) antibodies in Uganda.

DESIGN

This was an observational cross-sectional study.

SETTING

This study was conducted at Mulago National Referral Hospital, which is located in the capital city, Kampala, and includes the Uganda Heart Institute.

PATIENTS

Participants (aged 0-50 years) were recruited. Of 428 participants, 22 were excluded from analysis, and 183 (44.4%) of the remaining were children aged 5-15 years.

MAIN OUTCOME MEASURES

ASO was measured in-country by nephelometric technique. ADB samples were sent to Australia (PathWest) for analysis by enzyme inhibition assay: 80% upper limit values were established.

RESULTS

The median ASO titre in this age group was 220 IU/mL, with the 80th percentile value of 389 IU/mL. The median ADB titre in this age group was 375 IU/mL, with the 80th percentile value of 568 IU/mL.

CONCLUSIONS

The estimated Ugandan paediatric population standardised 80% upper-limit-of-normal ASO and ADB titres is higher than many global populations. Appropriateness of using population-specific antibody cutoffs is yet to be determined and has important implications for the sensitivity and specificity of rheumatic fever diagnosis.

Active Case Finding for Rheumatic Fever in an Endemic Country

Background Despite the high burden of rheumatic heart disease in sub-Saharan Africa, diagnosis with acute rheumatic fever (ARF) is exceedingly rare. Here, we report the results of the first prospective epidemiologic survey to diagnose and characterize ARF at the community level in Africa. Methods and Results A cross-sectional study was conducted in Lira, Uganda, to inform the design of a broader epidemiologic survey. Key messages were distributed in the community, and children aged 3 to 17 years were included if they had either (1) fever and joint pain, (2) suspicion of carditis, or (3) suspicion of chorea, with ARF diagnoses made by the 2015 Jones Criteria. Over 6 months, 201 children met criteria for participation, with a median age of 11 years (interquartile range, 6.5) and 103 (51%) female. At final diagnosis, 51 children (25%) had definite ARF, 11 (6%) had possible ARF, 2 (1%) had rheumatic heart disease without evidence of ARF, 78 (39%) had a known alternative diagnosis (10 influenza, 62 malaria, 2 sickle cell crises, 2 typhoid fever, 2 congenital heart disease), and 59 (30%) had an unknown alternative diagnosis. Conclusions ARF persists within rheumatic heart disease-endemic communities in Africa, despite the low rates reported in the literature. Early data collection has enabled refinement of our study design to best capture the incidence of ARF and to answer important questions on community sensitization, healthcare worker and teacher education, and simplified diagnostics for low-resource areas. This study also generated data to support further exploration of the relationship between malaria and ARF diagnosis in rheumatic heart disease/malaria-endemic countries.