Acute rheumatic fever: Clinical aspects and insights into pathogenesis and prevention

Streptococcus pyogenes ("Group A Streptococcus"), a Highly Adapted Human Pathogen-Potential Implications of Its Virulence Regulation for Epidemiology and Disease Management

Streptococcus pyogenes (group A streptococci; GAS) is an exclusively human pathogen. It causes a variety of suppurative and non-suppurative diseases in people of all ages worldwide. Not all can be successfully treated with antibiotics. A licensed vaccine, in spite of its global importance, is not yet available. GAS express an arsenal of virulence factors responsible for pathological immune reactions. The transcription of all these virulence factors is under the control of three types of virulence-related regulators: (i) two-component systems (TCS), (ii) stand-alone regulators, and (iii) non-coding RNAs. This review summarizes major TCS and stand-alone transcriptional regulatory systems, which are directly associated with virulence control. It is suggested that this treasure of knowledge on the genetics of virulence regulation should be better harnessed for new therapies and prevention methods for GAS infections, thereby changing its global epidemiology for the better.

Mechanistic implications of altered protein expression in rheumatic heart disease

Rheumatic heart disease (RHD) is a major cause of cardiovascular morbidity and mortality in low- and middle-income countries, where living conditions promote spread of group A β-haemolytic streptococcus. Autoimmune reactions due to molecular mimicry of bacterial epitopes by host proteins cause acute rheumatic fever (ARF) and subsequent disease progression to RHD. Despite knowledge of the factors that predispose to ARF and RHD, determinants of the progression to valvular damage and the molecular events involved remain incompletely characterised. This review focuses on altered protein expression in heart valves, myocardial tissue and plasma of patients with RHD and pathogenic consequences on RHD. Proteins mainly involved in structural organization of the valve matrix, blood homeostasis and immune response were altered due to RHD pathogenesis. Study of secreted forms of these proteins may aid the development of non-invasive biomarkers for early diagnosis and monitoring outcomes in RHD. Valve replacement surgery, the single evidence-based strategy to improve outcomes in severe RHD, is costly, largely unavailable in low- and middle-income countries (LMIC) and requires specialised facilities. When diagnosed early, penicillin prophylaxis may be used to delay progression to severe valvular damage. Echocardiography and cardiovascular magnetic resonance and the standard imaging tools recommended to confirm early diagnosis remain largely unavailable and inaccessible in most LMIC and both require expensive equipment and highly skilled persons for manipulation as well as interpretation of results. Changes in protein expression in heart valves and myocardium are associated with progressive valvular deformation in RHD. Understanding these protein changes should shed more light on the mechanisms of pathogenicity, while secreted forms of these proteins may provide leads towards a biomarker for non-invasive early detection of RHD.

Rheumatic fever: update on the Jones criteria according to the American Heart Association review - 2015

Rheumatic fever is still currently a prevalent disease, especially in developing countries. Triggered by a Group A β-hemolytic Streptococcus infection, the disease may affect genetically predisposed patients. Rheumatic carditis is the most important of its clinical manifestations, which can generate incapacitating sequelae of great impact for the individual and for society. Currently, its diagnosis is made based on the Jones criteria, established in 1992 by the American Heart Association. In 2015, the AHA carried out a significant review of these criteria, with new diagnostic parameters and recommendations. In the present study, the authors perform a critical analysis of this new review, emphasizing the most relevant points for clinical practice.

Infection with Chlamydia pneumoniae as a cause of coronary heart disease: the hypothesis is still untested

Review of the possible role of Chlamydia pneumoniae infection in the pathogenesis of heart disease.

The pattern of acute rheumatic fever in children: Experience at the children's hospital, Riyadh, Saudi Arabia

BACKGROUND

The study was carried out in Riyadh City Hospital to determine the hospital prevalence of acute rheumatic fever (ARF), its characteristics and to determine the proportion of the ARF population that have recurrent attacks.

METHODS

The study was an analysis of 83 children with ARF, admitted to the Children's Hospital, Riyadh, over a 10-year period (1994-2003). The diagnosis of ARF was based on clinical features as defined in the modified Jones criteria with evidence of recent streptococcal infection. The diagnosis of recurrence of rheumatic fever in children with rheumatic heart disease was based on the presence of one major criterion apart from carditis or two minor criteria, in addition to evidence of preceding streptococcal infection.

RESULTS

The mean age at presentation was 9 years. In 31 (37%) cases, arthritis was the only major Jones criterion. In 30 (36%) others, arthritis was associated with carditis and in 3 (4%), with chorea. Cardiac involvement was documented in 44 (53%) cases; it occurred alone in 5 (6%), with arthritis in 30 (36%), and with chorea in 9 (11%) others. Among the 44 with carditis, the pattern of cardiac involvement was valvular only (mild carditis) in 30 (68%), while it was severe in the remaining 14 (32%) cases who also had heart failure. The involvement of the mitral valve alone occurred in 26 (59%) cases in the form mitral regurgitation, while both aortic and mitral valve regurgitation were present in 11 (25%) cases, and aortic valve regurgitation alone in four (9%) others. Chorea was the only major criterion of ARF in 5 children (6%), while it occurred in association with other major criteria in 12 (15%) others. Nineteen (23%) children had recurrent attacks of ARF.

CONCLUSION

ARF continues to occur in Saudi Arabia in the period (1994-2003), despite the progress made in the socio-economic development of the country, and this is often associated with severe cardiac involvement.

Prevalence of rheumatic heart disease among school-children in Aden, Yemen

BACKGROUND

Rheumatic heart disease (RHD) is an important contributor to cardiovascular disease in children and adults in Yemen. This is the first report to determine the prevalence of RHD among school-children in the city of Aden.

METHODS

A cross-sectional case-finding survey of RHD was conducted in 6000 school-children aged 5-16 years. Echocardiography was undertaken in those with clinical signs of organic heart disease.

RESULTS

The prevalence of RHD was 36·5/1000 school-children, which is one of the highest reported among school echocardiography surveys in the world. RHD was more common in 10-16-year-old students. RHD was diagnosed in more than one member of the families of 53 (24·2%) of the children. Mitral regurgitation (MR) was detected in 49·8%, 26·6% had MR with mitral valve prolapse and 17·8% had combined MR and aortic regurgitation. Fifty-eight children were diagnosed with congenital heart disease (CHD), representing a prevalence of 9·7/1000. The main types of CHD were mitral valve prolapse, patent ductus arteriosus, atrial septal defect, pulmonary stenosis and aortic stenosis. Congenital mitral valve prolapse found in 36 children was three times more common in males than females. Children with RHD were more likely to be from low-income families with poor housing and greater overcrowding (49·3%, 39·3% and 64·8%) than children with CHD (44·8%, 32·8% and 48·3%, respectively).

CONCLUSIONS

The high prevalence of RHD is a major public health problem in Yemen. Urgent screening surveys and an RHD prophylactic programme of appropriate management of group A β-haemolytic streptococcal pharyngotonsilitis are required.