A Mathematical Model for Simulating Virus Transport through Synthetic Barriers

Abstract

Synthetic barriers such as gloves, condoms and masks are widely used in efforts to prevent disease transmission. Due to manufacturing defects, tears arising during use, or material porosity, there is inevitably a risk associated with use of these barriers. An understanding of virus transport through the relevant passageways would be valuable in quantifying the risk. However, experimental investigations involving such passageways are difficult to perform, owing to the small dimensions involved. This paper presents a mathematical model for analyzing and predicting virus transport through barriers. The model incorporates a mathematical description of the mechanisms of virus transport, which include carrier-fluid flow, Brownian motion, and attraction or repulsion via virus-barrier interaction forces. The critical element of the model is the empirically determined rate constant characterizing the interaction force between the virus and the barrier. Once the model has been calibrated through specification of the rate constant, it can predict virus concentration under a wide variety of conditions. The experiments used to calibrate the model are described, and the rate constants are given for four bacterial viruses interacting with a latex membrane in saline. Rate constants were also determined for different carrier-fluid salinities, and the salt concentration was found to have a pronounced effect. Validation experiments employing laser-drilled pores in condoms were also performed to test the calibrated model. Model predictions of amount of transmitted virus through the drilled holes agreed well with measured values. Calculations using determined rate constants show that the model can help identify situations where barrier-integrity tests could significantly underestimate the risk associated with barrier use.

Calculation of Brownian particle transmission in long, wide channels

“…The plots in Figure 2 demonstrate the plausibility of the hypothesis that the divergence between theory and experiments observed by Myers et al (1999) was due to a variance from the assumed flat geometry. Despite a slight overprediction by the calculations for the exponential geometry, the empirical trend with increasing R is captured remarkably well.…”

“…To determine the rate constant characterizing the interaction between viruses and a latex material in a saline medium, parallel vertical sheets were employed in the calibration experiments reported by Myers et al (1999). A spectrum of residence time/diffusion time values was used; in each experiment R was affected by the clamping compression keeping the sheets together, and determined from the measured fluid-flow rate Q via (The channel half-height h is proportional to Q'B (as in Eq.…”

“…A spectrum of residence time/diffusion time values was used; in each experiment R was affected by the clamping compression keeping the sheets together, and determined from the measured fluid-flow rate Q via (The channel half-height h is proportional to Q'B (as in Eq. Diamonds represent empirical data from the experiments reported by Myers et al (1999). Dotted line is the predicted transmission under the conditions of these experiments, assuming a flat channel.…”

“…This correspondence is shown by the data points and the dotted line in Figure 2. (The numerical approach used to compute the results represented by the dotted line is described in Myers et al (1999). Additional plots in Figure 2 will be discussed subsequently.)…”

Naprotecnología: ciencia y persona en la infección por el virus del papiloma humano (VPH) en mujeres y preadolescencentes

“…Este resultado parcial en el manejo de la exposición del VPH no ha conseguido controlar, del todo, la prevalencia de la infección en VPH en pacientes jóvenes. A este riesgo habría que sumar las interrupciones voluntarias del embarazo como consecuencia de los fallos debidos a los preservativos: porosidad, ruptura o mal uso (43). Estos fallos se han valorado mediante un modelo experimental que simula el riesgo real al cual se ve sometida la pareja usuaria de preservativo (riesgo que actualmente se encuentra infravalorado).…”