Streptococcal pharyngitis, rheumatic fever and rheumatic heart disease: Eight-year prospective surveillance in Rupnagar district of Punjab, India.

Background. Rheumatic fever (RF)/rheumatic heart disease (RHD) continue to be a neglected public health priority. We carried out a registry-based control project, prospective surveillance and sample surveys to estimate the burden of disease. Methods. We trained healthcare providers and established a surveillance system for the 1.1 million population of Rupnagar district in Punjab. In sample surveys conducted among schools, physicians examined the sampled children. Children with a cardiac murmur were investigated by echocardiography. Throat swabs were obtained from a sub-sample, and group A streptococci (GAS) were identified and emm typed by standard laboratory methods. We estimated the morbidity rates for RF/RHD from surveillance data and school surveys using a correction factor to account for under-registration of cases in the registry. Results. A total of 813 RF/RHD cases were registered from 2002 to 2009. Of the 203 RF and 610 RHD cases, respectively, 51.2% and 36.7% were males. In the age group of 5–14 years, RF was more common (80%) than RHD (27%). The prevalence of RF/RHD in 5–14-year-old students was 1.0/ 1000 (95% CI 0.8–1.3). The school survey indicated that about two-thirds of the RF/RHD cases were enrolled in the hospital-based registries. Based on the school survey, the prevalence of RF/RHD was estimated to be 143/100 000 population. In the registry, the annual incidence of acute RF was estimated to be at least 8.7/100 000 children in the age group of 5–14 years. The prevalence of GAS was 2% (13/656) in children with sore throat and 0.5% (14/2920) among those not having sore throat. Typing of 27 GAS revealed 16 emm types. We estimate that about 1000 episodes of GAS pharyngitis lead to one episode of acute RF. Conclusion. RF/RHD continue to be a public health problem in Punjab, India.

Pathology and pathogenesis of rheumatic heart disease.

Cardiovascular disease is on the rise. In India and other developing countries, rheumatic heart disease (RHD) continues to be a major public health problem and contributes to significant cardiac morbidity and mortality. RHD in the juvenile age group namely juvenile mitral stenosis is a variant which is unique to the Indian subcontinent. Severe valve deformities lead to high morbidity and mortality. Despite various measures no appreciable decline in prevalence of RHD has been documented. At autopsy, mitral valve was most commonly affected either alone or in combination with aortic and tricuspid valves. Both functional and organic involvement of tricuspid valve was documented. It has been convincingly demonstrated that molecular mimicry between Streptococcus pyogenes antigen and human proteins lead to autoimmune reactions both humoral and cell mediated causing RF/RHD. Heart tissues namely the valves, left atrial appendage (LAA) and myocardium reveal variable amounts of infiltration by lymphocytes. Significant endocarditis and valvulitis is observed in these cases. CD4+ T cells are most likely the ultimate effectors of chronic valve lesions in RHD. They can recognize Streptococcal M5 protein peptides and produce various inflammatory cytokines such as TNF-alpha, IFN-gamma, IL-10, IL-4 which could be responsible for progressive fibrotic valvular lesions. Cardiac myosin has been defined as a putative autoantigen recognized by autoantibodies of RF patients. Cross reactivity between cardiac myosin and group A beta hemolytic Streptococcal M protein has been adequately demonstrated. Cardiac myosin has been shown to produce myocarditis in rats and mice. Valvulitis/ endocarditis has been observed in excised LAA, cardiac valves and in hearts at autopsy from cases of RHD. The disease predominantly affects the valvular endocardium culminating in crippling valve deformities. Endocardial infiltrate and their migration into the valve substance has been elegantly demonstrated in rats and mice. Immune responses against cardiac myosin lead to valvular heart disease and infiltration of the heart by Streptococcal M protein reactive T lymphocytes. Mitral valves showed various degrees of calcification. An interesting observation is the nature of calcification in diseased/distorted valves in RHD. Recent studies indicate that calcification is not merely an inactive, "dystrophic" process but involves a regulated inflammatory process associated with expression of osteoblast markers and neoangiogenesis. Increased plasma osteopontin levels correlated with severity of mitral valve calcification. Further evidence of inflammation is supported by high levels of advanced oxidation protein products and high sensitive C-reactive protein in plasma detected in patients with RHD. Presence of inflammatory cells and increased expression of several cytokines in cases of "end stage" RHD reflects a possible subclinical, ongoing insult/injury to some unrecognized antigenic stimulus by beta hemolytic Streptococcal antigens that have sensitized/primed the various target tissues and which further culminate in permanent valve deformities.

Presencia de ADN bacteriano en el tejido valvular de pacientes con cardiopatía reumática crónica / Presence of bacterial DNA in valvular tissue of patients with rheumatic heart disease

Background: Rheumatic heart disease (RHD) is a delayed consequence of a pharyngeal infection with Group A streptococcus (GAS), usually ascribed to a cross-reactive immune response to the host cardiac tissues. Acute rheumatic fever (ARF) and its ensuing valvular sequelae are thus considered the prototype of a post-infectious autoimmune disease, with no direct evidence of residual streptococcal antigen in diseased valvular tissues. However, recent studies concerning the antigenic specificity and clonality of intralesional lymphocytes have revealed oligoclonal expansions characteristic of an antigen specific response, that might be related to GAS. Aim: To search for bacterial DNA in valvular tissue from RHD patients and controls. Material and methods: We extracted DNA from surgically excised valve specimens from 15 RHD patients and 6 non RHD controls and tested for the presence of bacterial DNA by Polymerase Chain Reaction (PCR) with primers for 16S rRNA. Results: Eighty percent (12/15) of valve specimens from RHD patients were positive for bacterial DNA, as opposed to none of the valves (n =6) from non RHD controls. Conclusions: These results suggest that GAS might persist in valvular tissue in patients with ARF and contribute to the inflammatory scarring lesion that leads to cardiovascular sequelae.

Coxsackie virus infections in rheumatic fever.

The close relationship between Group A beta Hemolytic Streptococci (GABS) and rheumatic fever is a well established one. However, the concept of the streptococcus as the sole etiologic agent of the rheumatic heart disease (RHD) has been challenged over the past years. Since coxsackievirus group B (CVB) has long been proposed as a cause of acquired valvular disease simulating rheumatic fever, we attempted in this study to document infections with this group of viruses in patients with rheumatic fever. We obtained blood samples from 106 patients with old (quiescent) rheumatic fever/rheumatic heart disease [group I], 94 patients with acute rheumatic fever (ARF) [group II], and 74 normal matched controls. We tested for the presence of neutralizing antibodies to the 6 serotypes of CVB by a micro neutralization test. We have found that infection with CVB, especially types B2 and B4, was common in the studied population. Forty-two percent of normal individuals had evidence of infection with any of the 6 serotypes of CVB. Patients of group I had significantly more frequent infections with CVB 2. Patients in group II had significantly more frequent infections with CVB 2 and CVB 6. There was no clear correlation between such infections and the clinical course of rheumatic fever. There was no difference in the incidence of CVB infections between patients with definite ARF, and patients with suspected ARF. We set a low order association between rheumatic fever and infection with CVB types B2 and B6. We emphasize the importance of pursuing the investigation of the role of CVB in relation to RHD.

Coxsackie virus and rheumatic fever. A correlative study.

Twenty-one patients of whom 13 had acute rheumatic fever and 8 had recurrence of rheumatic fever were studied for the evidence of coxsackie B viral infection using neutralisation test. A significant rise was noted in 17 cases (81%) and two cases had very high initial titre of neutralising antibodies to coxsackie B viruses type 1 to 6. Mixed infection with more than one serotype was seen in 11 cases. Coxsackie B2 was the commonest type and 14 patients had antistreptolysin 'O' anti-bodies. The high incidence of coxsackie B viral infection in rheumatic fever and the coexistent streptococcal infection and their relationship are discussed.