Avian influenza and the threat of the next human pandemic

Fast-track ventilation strategy to cater for pandemic patient isolation surges

BACKGROUND

The shortage of isolation facilities in hospitals was highlighted during the severe acute respiratory syndrome (SARS) pandemic in 2003. Yet, as the nature and scale of future pandemics cannot be adequately estimated, it is difficult to justify construction of sufficient isolation facilities. A fast-track and cost-effective ventilation strategy for the retrofitting of existing general wards could help hospitals deal with patient surges.

AIM

This article reviews the effectiveness of a fast-track, makeshift isolation approach employed during the SARS outbreak which involved installing simple window-mounted exhaust fans to create negative-pressure airflow in hospital general wards.

METHODS

Computational fluid dynamics (CFD) was used to assess by simulation whether the approach adopted meets US Centers for Disease and Control and Prevention requirements for properly constructed isolation wards.

FINDINGS

CFD simulation revealed that this makeshift approach could match the ventilation standards of isolation rooms. The approach was certainly effective as no secondary infections were reported in hospitals that used it during SARS.

CONCLUSIONS

When there is a shortfall in isolation facilities to accommodate a surge in patients, the proposed ventilation set-up could be quickly and widely implemented by existing general wards.

Dynamics of Single-City Influenza with Seasonal Forcing: From Regularity to Chaos

Seasonal and epidemic influenza continue to cause concern, reinforced by connections between human and avian influenza, and H1N1 swine influenza. Models summarize ideas about disease mechanisms, help understand contributions of different processes, and explore interventions. A compartment model of single-city influenza is developed. It is mechanism-based on lower-level studies, rather than focussing on predictions. It is deterministic, without non-disease-status stratification. Categories represented are susceptible, infected, sick, hospitalized, asymptomatic, dead from flu, recovered, and one in which recovered individuals lose immunity. Most categories are represented with sequential pools with first-order kinetics, giving gamma-function progressions with realistic dynamics. A virus compartment allows representation of environmental effects on virus lifetime, thence affecting reproductive ratio. The model's behaviour is explored. It is validated without significant tuning against data on a school outbreak. Seasonal forcing causes a variety of regular and chaotic behaviours, some being typical of seasonal and epidemic flu. It is suggested that models use sequential stages for appropriate disease categories because this is biologically realistic, and authentic dynamics is required if predictions are to be credible. Seasonality is important indicating that control measures might usefully take account of expected weather.

Pandemic influenza: human rights, ethics and duty to treat

The 2009 influenza A/H1N1 pandemic seems to be only moderately severe. In the future, a pandemic influenza with high lethality, such as the Spanish influenza in 1918-1919 or even worse, may emerge. In this kind of scenario, lethality rates ranging roughly from 2% to 30% have been proposed. Legal and ethical issues should be discussed before the incident. This article aims to highlight the legal, ethical and professional aspects that might be relevant to anaesthesiologists in the case of a high-lethality infectious disease such as a severe pandemic influenza. The epidemiology, the role of anaesthesiologists and possible threats to the profession and colleagueship within medical specialties relevant to anaesthesiologists are reviewed. During historical plague epidemics, some doctors have behaved like 'deserters'. However, during the Spanish influenza, physicians remained at their jobs, although many perished. In surveys, more than half of the health-care workers have reported their willingness to work in the case of severe pandemics. Physicians have the same human rights as all citizens: they have to be effectively protected against infectious disease. However, they have a duty to treat. Fair and responsible colleagueship among the diverse medical specialties should be promoted. Until disaster threatens humanity, volunteering to work during a pandemic might be the best way to ensure that physicians and other health-care workers stay at their workplace. Broad discussion in society is needed.

Synthesis of potent pyrrolidine influenza neuraminidase inhibitors

The synthesis of several pyrrolidine inhibitor analogs is described that possess nanomolar in vitro potencies against the neuraminidase enzymes expressed by the B/Memphis/3/89 and A/N1/PR/8/34 influenza strains.