Seroprevalence of anti-SARS-CoV-2 antibodies and risk of viral exposure among healthcare workers in the South Kivu province, eastern Democratic Republic of the Congo: a cross-sectional study.

OBJECTIVES: Healthcare workers (HCWs) are on the frontline of combating COVID-19, hence are at elevated risk of contracting an infection with SARS-CoV-2. The present study aims to measure the impact of SARS-CoV-2 on HCWs in central sub-Saharan Africa. SETTING: A cross-sectional serological study was conducted at six urban and five rural hospitals during the first pandemic wave in the South Kivu province, Democratic Republic of the Congo (DRC). PARTICIPANTS: Serum specimens from 1029 HCWs employed during the first pandemic wave were collected between August and October 2020, and data on demographics and work-related factors were recorded during structured interviews. PRIMARY AND SECONDARY OUTCOME MEASURES: The presence of IgG antibodies against SARS-CoV-2 was examined by ELISA. Positive specimens were further tested using a micro-neutralisation assay. Factors driving SARS-CoV-2 seropositivity were assessed by multivariable analysis. RESULTS: Overall SARS-CoV-2 seroprevalence was high among HCWs (33.1%), and significantly higher in urban (41.5%) compared with rural (19.8%) hospitals. Having had presented with COVID-19-like symptoms before was a strong predictor of seropositivity (31.5%). Personal protective equipment (PPE, 88.1% and 11.9%) and alcohol-based hand sanitizer (71.1% and 28.9%) were more often available, and hand hygiene was more often reported after patient contact (63.0% and 37.0%) in urban compared with rural hospitals, respectively. This may suggest that higher exposure during non-work times in high incidence urban areas counteracts higher work protection levels of HCWs. CONCLUSIONS: High SARS-CoV-2 seropositivity indicates widespread transmission of the virus in this region of DRC. Given the absence of publicly reported cases during the same time period at the rural sites, serological studies are very relevant in revealing infection dynamics especially in regions with low diagnostic capacities. This, and discrepancies in the application of PPE between urban and rural sites, should be considered in future pandemic response programmes.

Effects of Moringa oleifera aqueous seed extracts on reproductive traits of heat-stressed New Zealand white female rabbits.

Heat stress is reported to have deleterious effects on rabbit physiology by impairing reproductive performances arising from free radical production due to oxidative stress. Plant extracts have been listed among efficient and healthy strategies for alleviating the effects of free radicals in the body of an animal. Numerous studies have documented the medicinal value of Moringa oleifera on various body functional systems although most of these data have not been scientifically validated. The growing concern of heat stress owing to the effects of global warming has affected animal productivity and even reproductive health, yet mitigation measures are still scanty. To this end, we investigated the efficacy of Moringa oleifera aqueous seed extract on selected in the alleviation of morphofunctional impairments on functional systems of the body. Here, we quantified the effects of Moringa oleifera seed extracts on reproductive performances, hormonal profile, and ovarian histology in the management of heat stress in female rabbits. We were particularly interested in testing the hypothesis that Moringa oleifera seed extracts do not have medicinal value in the mitigation of oxidative stress accompanying heat-stressed animals and, therefore, affecting growth performance and reproductive value. Twenty-eight female rabbits aged 6 months and weighing between 2015.6 and 2322.7 g were randomly assigned to four treatment groups of temperature, relative humidity, temperature humidity index, and M. oleifera seed extracts as follows: T0: ambient temperature (18-24°C), 59 ± 0.48%, 23.6 ± 1.52; T1, T2, and T3: 35-36°C, 64 ± 0.6%, 32.5 ± 0.7, followed by 100, 200, and 0 mg/kg b.w of M. oleifera seed extracts. Artificial heat was introduced in each rabbit cage from 08:00 h to 16:00 h. Reproductive performances related to female rabbits and relevant biodata of their young ones were recorded. All animals were sacrificed at the end of 80 days of experiments, and blood was collected for hormonal assays and ovary tissues for histology. Data on hormones and reproductive parameters of adult females as well as parameters related to kid performance and milk yield were subjected to one-way ANOVA, and significant differences among treatment subjects were analyzed using Tukey's post-hoc test at 5% significance level. The results revealed a significant decrease (P < 0.05) in food consumption, body weight, and body weight gain in pregnant and lactating female rabbits exposed to heat stress. A decrease in fur removal by mothers, litter size from birth to weaning, litter weight, kid body weight, and body weight gain in adult rabbits submitted to heat stress was observed. The findings were also reflected on weekly milk yield and daily milk efficiency as well as serum hormone levels. Following administration of M. oleifera seed extracts at 200 mg/kg b.w., there was significant increase (P < 0.05) in these parameters. On the contrary, an increase (P < 0.05) in the number of services per conception, milk intake, and serum progesterone level was initially observed in the same subjects, but upon administration of M. oleifera seed extracts, there was a significant decrease (P < 0.05) on these measures. Ovarian histology of animals at T0 and T2 treatments showed structural features comparable to those of controls. Overall, our results show that administration of M. oleifera seed extracts at 200 mg/kg b.w possesses therapeutic value to the effects of oxidative stress associated with heat stress. Further pharmacological evaluation on seed extracts of M. oleifera may yield the much-needed medicine in the treatment and management of poor animal productivity and reproductive health arising from severe weather associated with global warming.