1951 Influenza Epidemic, England and Wales, Canada, and the United States

Death rates were substantially higher for England and Canada than for the United States

Radiographies intraorales : étude de qualité

When taking intraoral X-rays with a round collimator, the salivary glands and the thyroid gland are exposed to ionizing radiation. The rectangular collimator reduces the patient's radiation dose. This study aims to analyze the impact of the rectangular collimator on the quality of intraoral X-rays taken by students of the University Clinics of Dental Medicine (Geneva, Switzerland). Intraoral X-rays, performed by 8 students with digital intraoral phosphor plates, were collected and a quality score was assigned to each X-ray. A total of 130 intraoral radiographs were analyzed. Half of the radiographs were taken with a rectangular collimator and 24.6% (32/130) were bitewings. The mean quality score of bitewings taken with or without a collimator was 11 ± 1.8 and 10.3 ± 0.9, respectively. The mean quality score of apical X-rays taken with or without collimator was 11.6 ± 1.0 and 11.5 ± 2.1, respectively. X-rays taken with a rectangular collimator were of excellent or sufficient diagnostic quality for 95% of the bitewings and 100% of the periapical radiographs. This quality control study showing that students perform quality intraoral X-rays with a rectangular collimator could encourage clinicians to use this device as ameans of radiation protection in their daily practice

Aspectos epidemiológicos da meningite meningocócica no município de São Paulo (Brasil), no período de 1968 a 1974 Epidemiological aspects of meningococcal meningitis in the city of S. Paulo, Brazil from 1968 through 1974

Estudo epidemiológico da meningite meningocócica no município de São Paulo no período de janeiro de 1968 a junho de 1974. A partir de julho de 1971 uma epidemia causada pelo meningococo sorogrupo C ocorreu na área. Em abril de 1974 foi observado o início de uma segunda epidemia determinada pelo meningococo sorogrupo A. Os maiores coeficientes de morbidade durante o período estudado ocorreram: nos meses frios; nos distritos sanitários da periferia do município; no grupo etário de 0 a 4 anos, no sexo masculino. No primeiro mês das duas epidemias diferiu significantemente o grupo etário mais atingido. A letalidade decresceu de 15,0% em 1968-1970 para 7,9% em 1971-1974. Ela apresentou, durante o período epidêmico, uma variação sazonal no sentido inverso ao da morbidade.<br>An epidemiological study of meningococcal meningitis in the city of S. Paulo, Brazil (population in 1970: 5.931.935 inhabitants) during the period ranging from January 1968 to June 1974 was undertaken. Two outbreaks of meningococcal meningitis occurred during this period in the area under study. The first one began in July 1971, due to serogroup C Neisseria meningitidis; the second one began in april 1974, when the first outbreak had not yet finished and was caused by serogroup A Neisseria meningitidis. The attack rates were higher during the colder months. The majority of the cases occurred in the peripheric districts. Males and infants were at greatest risk. There ivas, however, a significant difference in the age of groups affected by the disease in the first month of both epidemics. The case-fatality ratios (deaths/cases) decreased from 15% (pre-epidemic period of 1968-1970) to 7,9% (epidemic period of 1971-1974.). There was a seasonal variation in the case-fatality ratio during the epidemic period: in colder months it decreased and in warmer months it increased