Preventing rheumatic heart disease in Australia

At the end of the 20th century, the good news about rheumatic fever is that it has become so rare in most of Australia that many medical practitioners will never see a case. This is a dramatic change from the first half of the century; in Melbourne during the 1930s, more than 50% of paediatric hospital medical beds were occupied by children with acute rheumatic fever or acute poststreptococcal glomerulonephritis, with rheumatic fever patients outnumbering those with glomerulonephritis (Dr Howard E Williams, previously In-Patient Physician, Royal Children's Hospital, Melbourne, personal communication). The decline of rheumatic fever in affluent populations occurred largely as a result of economic development and improved living conditions, with perhaps a small contribution from antibiotics and the possibly altered virulence of circulating group A streptococcal strains.¹

The bad news is that socially and economically disadvantaged populations worldwide, including some indigenous and minority populations living in affluent countries, continue to have high rates of rheumatic fever and rheumatic heart disease. The highest published incidence of acute rheumatic fever in the world is in Aboriginal people living in the "Top End" of the Northern Territory.² In this population the annual incidence of acute rheumatic fever (1989-1993) is between two and seven cases for every 1000 children aged 5 to 14 years, while up to three per cent of all people in some of the remote Aboriginal communities have established rheumatic heart disease. In contrast, the prevalence of rheumatic heart disease in the non-Aboriginal population is 0.014 per cent, and no non-Aboriginal children had acute rheumatic fever over this five-year period.²

While rheumatic fever appears to occur in only a subset of any given population, there are no data to support any major predisposition based on ethnicity. Similar high rates were documented in non-Aboriginal people in Melbourne during the 1930s and 1940s.³ The current high rates of rheumatic fever in the Aboriginal population are not related to ethnicity, but are likely to reflect high levels of exposure to group A streptococci, which, in turn, are related to overcrowding and continuing poor living conditions.^4,5

The World Health Organization has promoted the use of rheumatic fever registers in developing countries,⁶ with the major aims of coordinating individual patient management and improving adherence to secondary prophylaxis to prevent recurrent rheumatic fever and the associated cumul ative valve damage. Registers are useful not only for developing countries: a register-based program in New Zealand, with acute rheumatic fever as a notifiable disease, helped reduce from 22% to 6% the proportion of hospitalised cases of rheumatic fever which were recurrences.⁷

The Commonwealth Department of Health and Family Services, together with the Australian Institute of Health and Welfare, has taken the commendable step of funding a register-based control program in the Top End of the Northern Territory (Dr Vicki Krause, Director, Centre for Disease Control, Territory Health Services, Darwin, personal communication). This program will also involve new health promotion strategies in Aboriginal communities -- directed at both health and education staff and at people with rheumatic fever and rheumatic heart disease and their families. Videos, booklets and treatment charts have been developed by indigenous educators and researchers.⁸ The program will attempt to create a partnership for change, involving indigenous and non-indigenous health professionals and government and non-government health services.

Secondary prophylaxis will reduce the number of people developing rheumatic heart disease or requiring intervention for worsening valvular damage, but it will not stop initial episodes of acute rheumatic fever. This is where rheumatic fever control becomes difficult. While efforts to address social and economic inequities, particularly living conditions and overcrowding in Aboriginal communities, cannot be overemphasised,^4,5 in some remote communities substantial change in these areas has not been evident over the past two decades and, in the current economic climate, is unlikely, we believe, to occur for some time.

Conventionally, primary prevention relies on the accurate diagnosis and timely treatment with penicillin of group A streptococcal pharyngitis. However, most developing countries do not have the finances, skilled staff or laboratory facilities to do this well. Furthermore, more than two-thirds of cases of acute rheumatic fever may not follow symptomatic pharyngitis,⁹ so concentrating only on sore throats probably will not prevent most cases of rheumatic fever. Important progress is being made towards the development of a group A streptococcal vaccine, including current Australian initiatives,¹⁰ but in the shorter term other approaches are needed.

In one such approach, a program of regular throat swabbing and treatment of streptococcal carriers in one Aboriginal community appeared to coincide with fewer cases of rheumatic fever,¹¹ although the program was not sustained over the long term.¹² This program appears to be the sole published effort to improve primary prevention of acute rheumatic fever in an Aboriginal community.

While an association between streptococcal skin sores and acute rheumatic fever remains speculative, clues to further primary prevention strategies may come from understanding the epidemiology of group A streptococcal diseases in Aboriginal communities -- where the prevalence of streptococcal pyoderma (skin sores) may be up to 70% in children, but throat carriage rates of group A streptococci are often low.¹³ The ongoing epidemic of scabies in Aboriginal communities must underlie much of the streptococcal skin disease.

More research is needed to better understand the epidemiology and best management of sore throats, streptococcal pharyngitis and skin sores in Aboriginal communities, as well as the relationship between streptococcal throat and skin infections and rheumatic fever. In the meantime, primary prevention strategies should include measures to reduce the reservoir of circulating streptococci found in skin sores; coordinated programs to control skin sores and underlying scabies can be effective in Aboriginal communities.¹³ Successful primary prevention strategies developed in Australia could have global implications for rheumatic fever control.

Rheumatic heart disease in Aboriginal communities can be controlled in the short term through the use of comprehensive strategies to improve adherence to secondary prophylaxis regimens and to reduce exposure to group A streptococci, and possibly, in the longer term, with a vaccine. However, the ultimate aim must be improved living conditions for Aboriginal people, including emphasis on water supply, taps and showers, the disposal of sewage and solid waste, and resources to support better hygiene.