Book Reviews

Abandonment of Settlements and Regions: Ethnoarchaeological and Archaeological Approaches, edited by Catherine M. Cameron and Steve A. Tomka. Cambridge University Press. 1993. The Ouachita Mountains: A Guide for Fishermen, Hunters, and Travelers, by Milton D. Rafferty and John C. Catau. Norman: The University of Oklahoma Press. 1991. 308 pages, notes, references, index

Variation in Vector Competence for Dengue Viruses Does Not Depend on Mosquito Midgut Binding Affinity

Several factors, such as mosquito and virus genetics and environmental variables, determine the ability of mosquitoes to transmit dengue viruses. In this report, we describe new and important information that in some ways contradicts what is in the literature. Midgut infection barriers have been described as important determinants of virus transmission in mosquitoes but we found that virus binding to these midgut cells does not vary. When we compared binding of 8 different, low passage dengue viruses to mosquito midguts that were dissected out of Aedes aegypti mosquitoes (the main vectors of dengue) from Mexico and Texas, we found that there were no differences. Previously, we (and others) had shown that these same viruses differed significantly in replication and dissemination throughout the rest of the mosquito body, including the salivary glands, and therefore they differed greatly in their potential to be transmitted to humans. Thus, the data presented here are important considerations for future studies of vector competence and in determining strategies for control of dengue viruses in the vector

Immature Dengue Virus: A Veiled Pathogen?

Cells infected with dengue virus release a high proportion of immature prM-containing virions. In accordance, substantial levels of prM antibodies are found in sera of infected humans. Furthermore, it has been recently described that the rates of prM antibody responses are significantly higher in patients with secondary infection compared to those with primary infection. This suggests that immature dengue virus may play a role in disease pathogenesis. Interestingly, however, numerous functional studies have revealed that immature particles lack the ability to infect cells. In this report, we show that fully immature dengue particles become highly infectious upon interaction with prM antibodies. We demonstrate that prM antibodies facilitate efficient binding and cell entry of immature particles into Fc-receptor-expressing cells. In addition, enzymatic activity of furin is critical to render the internalized immature virus infectious. Together, these data suggest that during a secondary infection or primary infection of infants born to dengue-immune mothers, immature particles have the potential to be highly infectious and hence may contribute to the development of severe disease

Writer\u27s Block

Stop motion movie created by UNI art students and inspired by the writings of a Waterloo Writing Project author. Narration by the WWP author

Sleep Apnea and Hypoventilation in Patients with Down Syndrome: Analysis of 144 Polysomnogram Studies

Patients with Down syndrome (DS) are at risk for both obstructive sleep apnea (OSA) and central sleep apnea (CSA)however, it is unclear how these components evolve as patients age and whether patients are also at risk for hypoventilation. A retrospective review of 144 diagnostic polysomnograms (PSG) in a tertiary care facility over 10 years was conducted. Descriptive data and exploratory correlation analyses were performed. Sleep disordered breathing was common (seen in 78% of patients) with an average apnea-hypopnea index (AHI) = 10. The relative amount of obstructive apnea was positively correlated with age and body mass index (BMI). The relative amount of central sleep apnea was associated with younger age in the very youngest group (0-3 years). Hypoventilation was common occurring in more than 22% of patients and there was a positive correlation between the maximum CO2 and BMI. Sleep disordered breathing, including hypoventilation, was common in patients with DS. The obstructive component increased significantly with age and BMI, while the central component occurred most in the very young age group. Due to the high risk of hypoventilation, which has not been previously highlighted, it may be helpful to consider therapies to target both apnea and hypoventilation in this population