Influence of stenosis severity on hemodynamics flow at low Reynolds numbers: A computational fluid dynamic study

The restriction of blood flow due to narrowing of arteries that supply blood to different parts of the body leads to high blood pressure and cholesterol in humans. In this study, blood flow in a 3D model of arterial stenosis was examined using computational fluid dynamics (CFD) technique. The geometry of the stenosis was modeled using ANSYS software, and a structured tetrahedral mesh was generated for accurate representation. The CFD analysis was performed using the ANSYS (FLUENT) 19.2 commercial code to investigate three stenosis levels of 75%, 50%, and 25% over the Reynolds number range of 500-2000 with blood as the working fluid. The blood flowed steadily upstream of the stenosis as incompressible, homogeneous, and Newtonian, while the artery is considered to be inflexible. The Reynolds-averaged Navier-Stokes equations and the low Reynolds number SST k-ω turbulence model were employed to simulate the blood flow. The governing equations are solved, and the pressure-velocity coupling is handled using the SIMPLEC algorithm.  The steady state velocity and pressure generated at the inlet and outlet of the artery enabled the hemodynamic properties and flow reversal through arteries with a progressive amount of atherosclerosis to be determined. The results are presented in terms of velocity distribution, streamlines, and turbulence intensity contours. The results showed that at the throat (Z = 0) of the 75% stenosis, the relative magnitude of the velocity is greater than or equal to four times the average velocity. Reversal of flow is visible at   for Re = 500 and  for Re = 750 and Re = 2000. Furthermore, the effects of 25% stenosis on the flow pattern are relatively blunt and weak at . The throat of the stenosis, or a site therein, exhibits the highest value of centerline velocity, while turbulence intensity becomes severe at the post-stenotic site and they both increase with increasing stenosis level. The study provides valuable insights into the velocity distribution, flow reversal phenomenon, and turbulence intensity in arterial stenosis. The findings highlight the significant impact of stenosis levels and Reynolds numbers on the hemodynamic behavior, offering important considerations for understanding and managing arterial health issues

Orthopoxvirus Infections in Rodents, Nigeria, 2018–2019

To investigate animal reservoirs of monkeypox virus in Nigeria, we sampled 240 rodents during 2018–2019. Molecular (real-time PCR) and serologic (IgM) evidence indicated orthopoxvirus infections, but presence of monkeypox virus was not confirmed. These results can be used to develop public health interventions to reduce human infection with orthopoxviruses