A prospective study of corticosteroid and catecholamine levels in relation to viral respiratory illness.

Urinary 17-OHCS, epinephrine and norepinephrine levels were studied for one week before and one week after the onset of acute, severe Adenovirus 4 respiratory illness in 12 Army recruits during Basic Combat Training. During the pre-illness period, a tendency was frequently noted for all three hormone levels to show "spiking" elevations two to four days before illness onset. There was also a tendency for 17-OHCS levels to rise on the day before fever onset. The possible relationship of these pre-illness hormonal changes to stressful experiences and, in turn, to altered host resistance to infectious illness is discussed. Following onset of respiratory illness, 17-OHCS, epinephrine and norepinephrine levels all showed about 60 percent increases over the early pre-illness period baseline value. Elevations of these hormones persisted for about four to five days, roughly in correlation with fever duration, with only slight differences in configuration and timing of curves from one hormone to the next. The problem of evaluating which of several independent variables operating concurrently during infectious illness may be responsible for stimulating the final common neuroendocrine pathways is discussed.

Enteric immunization with live adenovirus type 21 vaccine. I. Tests for safety, infectivity, immunogenicity, and potency in volunteers.

Studies were undertaken in volunteers to determine whether living adenovirus type 21 (ADV-21) vaccine could be safely administered orally to susceptible young adults. In the first study, ten volunteers were fed 10(6.4) tissue culture infectious dose(50) (TCID(50)) of ADV-21 vaccine virus, and five received placebo tablets. Nine of ten infected volunteers shed ADV-21 in stools (mean duration, 10.1 days; range, 4 to 17 days). No pharyngeal excretion of ADV-21 was observed in any of these volunteers. Each of the nine developed type-specific neutralizing (N) antibodies to ADV-21. No evidence for person-to-person transmission of vaccine was observed. In a second study, volunteers were immunized with ADV-21 vaccines containing 10(6.8), 10(4.6), and 10(2.4) TCID(50). ADV-21 N antibody responses were detected in nine of eleven who received the highest dose, six of twelve who received the middle dose, and two of twelve who were fed the lowest dose. None of twelve susceptible volunteers receiving the placebo capsule developed ADV-21 N antibodies postimmunization. This study established that the human infectious dose(50) for these lots of ADV-21 vaccine was approximately 10(4.6) TCID(50) and that the dose response to ADV-21 vaccine was lower than those previously reported for live ADV-4 and ADV-7 enteric vaccines.

Physical and biological properties of dengue-2 virus and associated antigens.

Dengue virus suspensions from mouse brain and cell culture were fractionated into three components by rate zonal centrifugation in sucrose gradients. Infectious virus sedimented in a single zone and possessed hemagglutinating (HA) and complement fixing (CF) activity. Electron micrographs showed the virion to be a spherical particle 48 to 50 nm in diameter with 7-nm spherical structures on its surface. Buoyant density in CsCl of virions from mouse brain was estimated at 1.22 g/cm(3) and from cell culture at 1.24 g/cm(3). During centrifugation of virions in CsCl, an additional HA component appeared with a buoyant density of 1.18 g/cm(3). It was shown in electron micrographs to consist of virion fragments. A noninfectious component with HA and CF activity sedimented in sucrose more slowly than intact virus, had a buoyant density of 1.23 g/cm(3) in CsCl, and appeared as "doughnut" forms measuring 13.8 to 14 nm in diameter. A third component, with CF activity and no HA activity, sedimented very little in sucrose gradients. Particles of the same size and shape as the spherical subunits on the surface of the virion were observed in electron micrographs.

La experiencia con la influenza de Hong Kong en Zonas Tropicales / Experience with Hong Kong influenza in Tropical Areas

Following the introduction of A2/Hong Kong/68 influenza virus into 2 different susceptible populations residing in Thailand and the Panama Cnal Zone, epidemic disease occurred within approximately 1 month. The estabishment and transmission of the virus, and the disease it caused, were studied in detail. The rates of progression and extent of overt epidemic disease and the proportions of overt to subclinical infection in the 2 areas were different. In Korat Royal Thai Air Force Base, only 8 percent of US servicemen became ill, although 13 percent of them were infected. The epidemic progressed slowly, so that no more than 1.5 percent of the population were ill at any one time during the 3 months of its recognized presence. In contrast, in the Canal Zone the clinical attack rate approached 50 percent, and subclinical infection occurred in 5 percent or less of the population during a 6-week period when absenteeism from schools and work was quite obvious. Factors such as immunization status of the populations and virulence of virus seemed not to be primarily responsible for the differences. Rather, the latter appear to be realted to differences in environmental circumstances, with crowding contributing to the higher disease incidence in the Canal Zone

The data show that this variant A2 virus may produce different epiemiological patterns of disease in tropical areas, similar to those observed in ...(AU)