The changing pattern of infectious disease

Several factors contribute towards a decrease in the prevalence of infectious disease in a population. These include active control measures, active immunisation, and improvement in the socioeconomic state of the population. There appears, however, to be a progressive increase in the resistance of a population in relation to the length of time the population has been exposed to an agent. This increasing resistance is currently thought to be an expression of natural selection but transmission of actively acquired immunity cannot be ruled out and in the light of current evidence remains a highly probable contributory factor.     

The changing pattern of ischemic heart disease

Male and female death rates from all the major forms of cardiovascular disease were approximately equal until about 1920. Since that time the male:female ratio in fatal ischemic heart disease (IHD) has risen dramatically, but some closely related diseases such as cerebrovascular disease and uncomplicated angina pectoris have maintained sex ratios close to unity. It is difficult to reconcile this divergent trend in the sex ratio of IHD with a simple stenotic-thrombotic view of myocardial infarction (MI) and it is suggested that the modern epidemic of MI in men may be the result of a disorder of muscle metabolism (“vulnerable myocardium”) superimposed on a relatively stable background of stenotic-thrombotic arterial disease. The proposed mechanism would also help to explain the selective action of some modern “coronary risk factors” (such as cigarette smoking and physical inactivity) which increase the risk of MI but have little or no effect on the risk of developing cerebrovascular disease or uncomplicated angina pectoris.     

Black-white differences in stroke incidence in a national sample. The contribution of hypertension and diabetes mellitus

Although national data have consistently shown an increased risk of death from stroke among blacks, few studies have addressed the reasons for this excess mortality. We compared the incidence of stroke among 1298 blacks and 7814 whites, aged 35 to 74 years, in the 10-year follow-up of the respondents from the First National Health and Nutrition Survey. Blacks had a higher estimated incidence of stroke than whites even after adjustment for age, hypertension, and diabetes mellitus; the relative risk was 1.4 (95% confidence interval, 1.0 to 2.0) for black women and 1.1 (95% confidence interval, 0.8 to 1.6) for black men. The relative risks for stroke associated with hypertension and diabetes mellitus were unrelated to race. Although efforts to treat hypertension and diabetes are among the most important public health measures for reducing stroke, a more complete understanding of the determinants of stroke may be required to account for the excess stroke risk experienced by blacks.     

The changing pattern of fetal hydrops.

Fetal hydrops (hydrops fetalis) remains a significant cause of fetal and neonatal mortality. The decreased incidence of rhesus iso-immunisation due to prophylaxis with rhesus immune globulin (anti-D), improved antenatal ultrasound screening, and advances in neonatal intensive care have greatly altered the clinical outlook in this condition. A retrospective review of all 27 liveborn cases of hydrops in the Royal Maternity Hospital, Belfast in the period 1974-89 showed that in the last five years 40% of cases were non-immune in origin. The mortality rate fell from 100% in the first part of the study to 50% in the second.     

The changing pattern of toxicity of digoxin.

Toxicity to digoxin was monitored in 437 consecutive recipients in a comprehensive drug surveillance programme, Adverse reactions developed in 19.5% and, in contrast to previous reports, were generally of a relatively benign nature. There were no drug-related deaths, but patients with adverse reactions spent longer in hospital. Low body weight, impaired renal function, old age and concurrent use of diuretics individually did not increase the risk of toxicity. This was attributed to improvements in the prescribing of digoxin. There was a highly significant excess of gastrointestinal reactions in women, which tended to occur early in the course of therapy. This susceptibility is not widely recognized. The use of loading doses may have caused many early reactions and it is suggested that this practice cold be abandoned in all but the most urgent cases.     

The changing pattern of Tinea capitis in Jamaica

The species of dermatophyte fungi causing tinea capitis vary from country to country and may also change with time. This study was done to identify the predominant organisms causing tinea capitis in the Jamaican population. It was a retrospective study looking at all fungal culture requests to the Microbiology Department at the University Hospital of the West Indies during the period January 1, 1998 to December 31, 2002. The results showed a gradual switch from the dominance of Microsporum audouinii (61.5%) in 1998 to the dominance of Trichophyton tonsurans (85%) in 2002. The mean age was 8.6. Females constituted 55.7% of positive cases and males, 44.3%.