The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Epidemic in Zimbabwe: Quo Vadis?

The trajectory and impact of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in sub-Saharan Africa are unclear, but they are seemingly varied between different countries, with most reporting low numbers. We use the situation in Zimbabwe to build an argument that the epidemic is likely to be attenuated in some countries with similar socioeconomic and cultural structures. However, even an attenuated epidemic may overwhelm weak health systems, emphasizing the importance of prevention. These prevention strategies should be tailored to the unique social and cultural networks of individual countries, which may facilitate the spread of SARS-CoV-2. It is also equally important to maintain services for the major infectious diseases in the region, such as tuberculosis and malaria. A breakdown of treatment and prevention services for these conditions may even overshadow the projected morbidity and mortality from coronavirus disease 2019 (COVID-19).

Vasomotor sympathetic outflow in the muscle metaboreflex in low birth weight young adults.

A growing body of evidence suggests that low birth weight (LBW) offspring are associated with long-term structural and functional changes in cardiovascular and neuroendocrine systems. We tested the hypothesis that muscle metaboreflex activation produces exaggerated responses in cardiac autonomic tone (represented by heart rate variability ratio) and cutaneous vascular sympathetic tone (represented by plethysmography pulse wave amplitude) in LBW compared to normal birth weight (NBW) young adults. We recruited 23 LBW (18 females and five males) and 23 NBW (14 females and nine males) University of Zimbabwe students with neonatal clinical cards as proof of birth weight at term. Resting electrocardiogram, pulse waves, and blood pressures were recorded. Participants then underwent a static/isometric handgrip exercise until fatigue and a post-exercise circulatory arrest period of 2 minutes. We observed (results mean ± standard deviation) a greater mean increase in heart rate variability ratio from baseline to exercise for LBW compared to NBW individuals (1.015±1.034 versus [vs] 0.119±0.789, respectively; P<0.05). We also observed a greater mean decrease in plethysmography pulse wave amplitude from baseline to exercise (-1.32±1.064 vs -0.735±0.63; P<0.05) and from baseline to post-exercise circulatory arrest (-0.932±0.998 vs -0.389±0.563; P<0.05) for LBW compared to NBW individuals. We conclude that LBW may be associated with an exaggerated sympathetic discharge in response to muscle metaboreflex.

Exercise-induced cardiac fatigue in low and normal birth weight young black adults.

The objective of the study was to compare the change in diastolic function, E/A ratio, in response to prolonged exercise in low birth weight and normal birth weight individuals. Using a case-control study design, 23 students of the University of Zimbabwe College of Health Sciences who had neonatal clinic cards as proof of birth weight were recruited into the study. Measurements of diastolic function, E/A ratio, were obtained using an echocardiogram before and after 75 minutes of exercise. Among the cohort, seven had low birth weight - <2500 g, three female patients and four male patients - and 16 had normal birth weight - six female patients and 10 male patients). The mean age was 20.7±3.3 years. After prolonged exercise for 75 minutes of running on a treadmill, decreases in diastolic function, E/A ratio, were significantly greater in low birth weight than in normal birth weight individuals (0.48±0.27 versus 0.19±0.18 p<0.05, respectively). There was a significant association between low birth weight and exercise-induced cardiac fatigue (the χ2 test p<0.05, odds ratio 4.64, 95% confidence interval 1.19-18.1). We conclude that low birth weight is associated with exercise-induced diastolic dysfunction in young adults.