An approach to estimating tuberculosis incidence and case detection rate from routine notification data.

OBJECTIVE: To estimate tuberculosis (TB) incidence and case detection rate (CDR) using routine TB surveillance data only. METHODS: A mathematical model of the case detection process, representing competition between disease progression and case finding, is proposed. The model describes disease progression as a two-stage process (bacillary and non-bacillary TB), and so relates the proportion of bacillary TB cases on detection to the effectiveness of detection. Thus, given the annual numbers of newly detected TB cases stratified by bacillary status, the model estimates detection rates, incidence and CDR. Routine notification data from eight provinces in Russia, 2000-2011, were used for the study. RESULTS: Subnational level estimates of incidence and CDR were obtained. Incidence estimates varied by two-fold among the provinces; corrected CDR estimates varied by 1.5 times. The trend in the incidence estimates was similar to that in the World Health Organization estimates for the whole of Russia. The change in the trend in WHO CDR estimates in 2008-2009 was not supported by our estimates. CONCLUSION: The general approach that uses multistage models of disease progression and accordingly stratified notification data can be applied in various settings for the routine estimation of incidence and CDR.

[A model of resource reallocation during physiological adaptation in Mediterranean fruit fly females]. / Model' pereraspredeleniia resursa v khode fiziologicheskoi adaptatsii samok sredizemnomorskoi fruktovoi mukhi Ceratitis capitata.

Analysis of experimental data on longevity and fertility of females of Mediterranean fruit fly Ceratitis capitata demonstrates that flies lay fewer eggs on the average as the average life-span increases. At the same time, the values of individual life-span and the number of eggs laid are positively correlated. To explain these results, a resource model describing the allocation and reallocation of resources between two basic functions, reproduction and maintenance, was proposed. The reallocation of resources, is triggered by changes in environmental conditions such as diet changes, and the parameters of reallocation depend on the current environmental conditions. Modeling demonstrated that the results of experiments are greatly influenced by population selection and heterogeneity.

The impact of diet switching on resource allocation to reproduction and longevity in Mediterranean fruitflies.

Understanding the factors that determine the allocation and utilization of organism resources may provide an insight into the mechanisms of adaptation, ageing and reproduction. Resource allocation, which is regarded as a method of adaptation, increases fitness and is genetically controlled. Experiments with variable diet feeding of female Mediterranean fruitflies (Ceratitis capitata) demonstrated that the feeding regime dramatically influences lifespan, mortality and the reproduction of flies. An analysis of experimental data and numerical experiments reveals that resource allocation could explain lifespan increase when females are switched from a sugar-only to a protein-containing diet. The heterogeneity of the initial female cohort in terms of the total amount of resources and its allocation to the processes of maintenance and reproduction plays a significant role in this.