Likely effectiveness of pharmaceutical and non-pharmaceutical interventions for mitigating influenza virus transmission in Mongolia.

OBJECTIVE: To assess the likely benefit of the interventions under consideration for use in Mongolia during future influenza pandemics. METHODS: A stochastic, compartmental patch model of susceptibility, exposure, infection and recovery was constructed to capture the key effects of several interventions--travel restrictions, school closure, generalized social distancing, quarantining of close contacts, treatment of cases with antivirals and prophylaxis of contacts--on the dynamics of influenza epidemics. The likely benefit and optimal timing and duration of each of these interventions were assessed using Latin-hypercube sampling techniques, averaging across many possible transmission and social mixing parameters. FINDINGS: Timely interventions could substantially alter the time-course and reduce the severity of pandemic influenza in Mongolia. In a moderate pandemic scenario, early social distancing measures decreased the mean attack rate from around 10% to 7-8%. Similarly, in a severe pandemic scenario such measures cut the mean attack rate from approximately 23% to 21%. In both moderate and severe pandemic scenarios, a suite of non-pharmaceutical interventions proved as effective as the targeted use of antivirals. Targeted antiviral campaigns generally appeared more effective in severe pandemic scenarios than in moderate pandemic scenarios. CONCLUSION: A mathematical model of pandemic influenza transmission in Mongolia indicated that, to be successful, interventions to prevent transmission must be triggered when the first cases are detected in border regions. If social distancing measures are introduced at this stage and implemented over several weeks, they may have a notable mitigating impact. In low-income regions such as Mongolia, social distancing may be more effective than the large-scale use of antivirals.

Serum UDP-galactose: glycoprotein galactosyltransferase in diabetics with microangiopathy.

1. Levels of serum UDP-galactose:glycoprotein galactosyltransferase in 117 unselected diabetics were compared with those in 60 non-diabetic healthy controls. 2. Enzyme activity (mean +/- 2 S.D.) of control sera was found to be 90.2 +/- 21.5 etamoles/ml/hr at 37 degrees. In 30 of the 117 diabetic sera (26%) enzyme activity was elevated (greater than mean + 2 S.D. of the controls). Sixteen of 19 (84%) patients with retinopathy, 16 of 26 (62%) patients with peripheral vasculopathy and 13 of 26 (50%) patients with neuropathy had higher levels of serum enzyme. When serum enzyme levels of groups of diabetics with retinopathy, peripheral vasculopathy and neuropathy were compared with the enzyme level in all diabetics, there was a significant difference with p values of 0.001, 0.05 and 0.05 respectively.

The influence of changing host immunity on 1918-19 pandemic dynamics.

The sociological and biological factors which gave rise to the three pandemic waves of Spanish influenza in England during 1918-19 are still poorly understood. Symptom reporting data available for a limited set of locations in England indicates that reinfection in multiple waves occurred, suggesting a role for loss of infection-acquired immunity. Here we explore the role that changes in host immunity, driven by a combination of within-host factors and viral evolution, may play in explaining weekly mortality data and wave-by-wave symptomatic attack-rates available for a subset of English cities. Our results indicate that changes in the phenotype of the pandemic virus are likely required to explain the closely spaced waves of infection, but distinguishing between the detailed contributions of viral evolution and changing adaptive immune responses to transmission rates is difficult given the dearth of sero-epidemiological and virological data available even for more contemporary pandemics. We find that a dynamical model in which pre-pandemic protection in older "influenza-experienced" cohorts is lost rapidly prior to the second wave provides the best fit to the mortality and symptom reporting data. Best fitting parameter estimates for such a model indicate that post-infection protection lasted of order months, while other statistical analyses indicate that population-age was inversely correlated with overall mortality during the herald wave. Our results suggest that severe secondary waves of pandemic influenza may be triggered by viral escape from pre-pandemic immunity, and thus that understanding the role of heterosubtypic or cross-protective immune responses to pandemic influenza may be key to controlling the severity of future influenza pandemics.

Survival of Staphylococcus aureus and enterotoxin A in glassy and rubbery states of gelatin.

About 1% of Staphylococcus aureus cells survived the production of gelatin sheets containing nutrient broth. Those cells which survived showed no evidence of injury. Growth occurred in rubbery state gelatin with a(w) values of 0.98 and 0.93 ; viability decreased during storage at a(w) values of 0.89, 0.62 and 0.36 but there was little loss of viability in gelatin at an aw of 0.25 over 27 d storage at 26 degrees C. Assays for enterotoxin A detected no synthesis of new toxin but no loss in pre-formed toxin. The results suggest that high levels of Staph. aureus and its toxins should be excluded from glassy and rubbery state food products in order to prevent illness.

Survival of Salmonella senftenberg and Salmonella typhimurium in glassy and rubbery states of gelatin.

Salmonella senftenberg and Salmonella typhimurium survived the production of gelatin sheets containing nutrient broth although there was some evidence of cell damage. Both strains survived but did not grow in glassy states with an a(w) of 0.45-0.28 and rubbery states with an a(w) of 0.93-0.96 for at least 28 d. Survival was less in intermediate states with an a(w) between 0.55 and 0.74. The results suggest that salmonellas should be excluded from glassy state products in order to prevent salmonellosis.