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Biomedical subjects

T H Weller

Publications and source records attributed to T H Weller.

At least 19 recordsLinked to original sources
PubMed1996

Varicella: historical perspective and clinical overview.

In immunocompetent children in Europe and the United States, varicella is usually a benign disease. However, infants born to women who acquire varicella during or shortly after pregnancy are at high risk of infection. For unknown reasons, the disease is more severe in adolescents and adults, with pneumonia the most common cause of death. Varicella may also be lethal in patients of any age in the presence of biologic or iatrogenic immunosuppression. It is now well documented that varicella-zoster virus remains latent in the dorsal root and cranial ganglia following an attack of varicella. Viral reactivation appears with advancing age as cellular immunity wanes. The contemporary relative aging of the population will enhance the social significance of zoster. The immigration of nonimmune adults in temperate climates poses a major problem in terms of protection of high-risk children. A vaccination program is indicated.

Adult↗
PubMed1992

Varicella and herpes zoster: a perspective and overview.

The events leading to the isolation of varicella-zoster virus (VZV) are described beginning with the pioneering contributions of Ernest Tyzzer and Ernest Goodpasture and the early epidemiologic observations that indicated a relationship between varicella and zoster. Isolation, propagation, and immunologic proof of the coidentity of the viruses from the two clinical entities evolved from the introduction of human cell culture systems, a development that revolutionized virus research. Now the social significance of VZV is increasing. This reflects an aging population, increasing use of immunosuppressive therapeutic procedures, and the advent of a biologic immunosuppressive agent, the virus that causes AIDS. Currently there are unsolved problems: For unknown reasons varicella is often an adult disease in the tropics, and cell cultures fail to demonstrate VZV in throat washings from cases. These peculiarities warrant elucidation.

Aging↗
PubMed1990

A nine year prospective study of Chagas' disease in a defined rural population in northeast Brazil.

The association between infection with Trypanosoma cruzi and the development of electrocardiographic alterations and mortality was studied longitudinally for 9 years in a population residing in an endemic area in Castro Alves, Bahia, Brazil. Annual censuses were begun in 1973. At 3 year intervals from 1974 to 1983, the population was examined serologically and subjected to electrocardiography using standardized techniques. Of 1,751 individuals registered during the 10 censuses, 1,541 (88%) were examined serologically at least once. Of 747 individuals in constant residence and originally seronegative, 24 were seropositive upon subsequent evaluation, giving a seroconversion rate of 4.92/1,000 person-years (PY). The overall rate of development of an abnormal ECG was 25.7/1,000 PY for seropositive individuals and 12.5/1,000 PY for seronegative individuals, a relative risk of 2. The 10-14-year-old seropositive group had the highest risk of developing ECG abnormalities (24.1/1,000 PY, relative risk = 3.5). The age-adjusted mortality rate of seropositive individuals was slightly higher than for seronegative individuals (8.9 vs. 7.8/1,000 PY). In sero-positive individuals, mortality was strongly associated with the presence of ventricular conduction defects and arrhythmias. Ventricular conduction defects appeared most frequently in younger individuals. Older individuals presented the highest risk of development of frequent and multifocal extrasystoles.

Adolescent↗
PubMed1987

Cardiac morbidity and mortality due to Chagas' disease: prospective electrocardiographic study of a Brazilian community.

The evolution of Chagas' cardiomyopathy is poorly understood. We therefore examined the development of cardiac lesions in a rural Brazilian community for a period of 7 years. Initially, 42% of 1017 residents were seropositive for infection with Trypanosoma cruzi. Age-specific infection rates indicated that most had become infected before the age of 20 years. On follow-up, it appeared that those persons who developed cardiac lesions did so soon after infection, since the incidence of right bundle branch block and other ventricular conduction defects (VCDs) was also highest before age 20 years. The progressive nature of these lesions was demonstrated by frequent development of additional electrocardiographic abnormalities and high mortality among infected adults with VCDs. In contrast, mortality was low and approximately the same for seropositive and seronegative adults under 60 years who had normal electrocardiograms. Electrocardiography during the early asymptomatic stage of infection was able to distinguish persons with potentially lethal cardiac lesions from those with a benign prognosis.

Age Factors↗