BACKGROUND
Two sub variants (BA.4 and BA.5) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant are concerning as they are spreading rapidly worldwide; however, no published data concerning these variants are available in Cameroon. We report the early detection of these new sub variants that are associated with the onset of the fifth wave of coronavirus 2019 (COVID-19) in Cameroon.
METHODS
Positive samples were selected for next-generation sequencing (NGS). BA.4 and BA.5 complete genome sequences underwent sequence data analysis, epidemiology analysis of COVID-19’s resurgence and wave, recombination and pairwise matrix analysis, and phylogenetic analysis. We selected the first nine SARS-CoV-2 Omicron BA.4 and BA.5 sub variants detected in Cameroon using local whole genome sequencing for the NGS analysis.
RESULTS
During the fifth wave of resurgence of COVID-19 cases in Cameroon, it was found that the Northwest and Littoral regions were the most affected areas, while the Center and Littoral regions recorded the highest number of new deaths. The study identified evidence of recombination between the BA.2 sub variant and BA.4 and BA.5 Cameroonian strains. This result highlights the dynamic nature of SARS-CoV-2 evolution. The BA.5 strain (entitled hCoV-19/Cameroon/23850/2022) showed the highest sequence similarity to the first reported genome of the Omicron strain with 497 mutations. Phylogenetic analysis revealed that these nine Omicron sub variants were grouped into a distinct and highly distant cluster separate from the first Omicron variant detected in Botswana and were intermixed with sequences from other countries (the United States, Denmark, Scotland, and England), thus implying multiple introductions of the BA.4 and BA.5 sub variants in Cameroon.
CONCLUSIONS
Omicron BA.4 and BA.5 sub-lineages are associated with the onset of the fifth wave of COVID-19 in Cameroon. In addition to providing early warning of COVID-19 resurgence, continuous local genome sequencing of emerging variants is essential for detecting variants of concern, thereby guiding the country's response. This study emphasizes the value of real-time surveillance.
Current malaria diagnostics are invasive, lack sensitivity, and rapid tests are plagued by deletions in target antigens. Here we introduce the Cytophone, an innovative photoacoustic flow cytometer platform with high-pulse-rate lasers and a focused ultrasound transducer array to noninvasively detect and identify malaria-infected red blood cells (iRBCs) using specific wave shapes, widths, and time delays generated from the absorbance of laser energy by hemozoin, a universal biomarker of malaria infection. In a population of Cameroonian adults with uncomplicated malaria, we assess our device for safety in a cross-sectional cohort (n = 10) and conduct a performance assessment in a longitudinal cohort (n = 20) followed for 30 ± 7 days after clearance of parasitemia. Longitudinal cytophone measurements are compared to point-of-care and molecular assays (n = 94). Cytophone is safe with 90% sensitivity, 69% specificity, and a receiver-operator-curve-area-under-the-curve (ROC-AUC) of 0.84, as compared to microscopy. ROC-AUCs of Cytophone, microscopy, and RDT compared to quantitative PCR are not statistically different from one another. The ability to noninvasively detect iRBCs in the bloodstream is a major advancement which offers the potential to rapidly identify both the large asymptomatic reservoir of infection, as well as diagnose symptomatic cases without the need for a blood sample.
BACKGROUND
The rate of TB in prison institutions is estimated to be 23 times higher than in the general population. Limited documentation exists regarding TB screening in Tajikistan's prisons. This study aims to report findings from a TB screening conducted in prison facilities in Tajikistan.
METHODS
A systematic TB screening was conducted between July 2022 and September 2023, following a locally adapted algorithm based on WHO recommendations. The screening yield was calculated as the proportion of confirmed TB cases, with categorical variables compared using a χ2 test.
RESULTS
A total of 7,223 screenings were conducted, identifying 31 TB cases, including 17 drug-susceptible TB cases, eight drug-resistant TB cases, and six clinically diagnosed cases. The overall screening yield was 0.43%. Notably, the screening yield was 3.4% among individuals with at least one TB symptom and 0.03% among those without TB symptoms (P < 0.001).
CONCLUSION
The identified rate of TB in these prisons is five times higher than in the general population. Symptomatic individuals had a higher likelihood of TB diagnosis, and using chest X-rays significantly improved screening yield. We recommend increasing the capacity for chest X-ray testing to enhance TB prevention and control within prison settings.
The 2014 West Africa Ebola outbreak underlined inadequacies of current personal protective equipment (PPE), such as being uncomfortable and hot, causing excessive sweating and rapid exhaustion, and limiting interactions between health workers and patients. The smartPPE development project responded to the urgent need for a more comfortable, simpler, and sustainable PPE solution for filovirus-outbreak front-line workers. A one- piece, reusable smartPPE with ventilation system was developed to address these challenges. We assessed ease-of-use, comfort, functionality, and perceived doffing-safety of the smartPPE prototype compared with currently used PPE (current-PPE) under simulated field conditions.
METHODS
In June 2023, we conducted a mixed-methods crossover usability study in a controlled high-heat/high-humidity indoor site in Brindisi, Italy. Ten test users (three female, seven with filovirus-front-line experience) assessed smartPPE and current- PPE in four guided sessions covering donning, (emergency) doffing, clinical tasks, and heavy physical WATSAN activities. User feedback was collected through structured questionnaires. Temperature, humidity, session duration, and vital signs were measured, and perceived exertion was assessed using Borg- scores (scale 6–20).
RESULTS
Median temperature and humidity were higher inside current- PPE than inside smartPPE (difference: 2.3°C [IQR 1.8–3.0] and 12.6 percentage points [8.8–19.6], respectively). Users endured heavy work sessions for significantly longer in smartPPE than in current-PPE (80.0 min [IQR 75–84] vs 49.5 min [45–56]). Median increases in body temperature (1.1°C [IQR 0.7–1.6] vs 0.7°C [0.3–0.9]; p<0.001) and respiratory rate (3.5 rpm [1–5] vs 1.5 rpm [0–3]; p=0.034), and reductions in O2 saturation (–2% [–5 to –1] vs –1.5% [–3 to 0]; p=0.027) were higher with current-PPE than with smartPPE. Peripheral vision was similarly rated, but hearing was compromised with smartPPE at ≥5 m. Median exertion- scores were lower for smartPPE (clinical tasks 8.5 [IQR 7–11] vs 15.5 [14–16] p<0.01; heavy physical activities 14 [13–17] vs 18 [17–20] p=0.035). All users preferred smartPPE for overall and thermal comfort, breathing, and doffing-safety; nine (90%) favoured it for non-verbal communication, eight (80%) for vision or longer-interval heavy WATSAN activities, six (60%) for longer- interval patient care, six (60%) for short-term clinical activities, and six (60%) for emergency doffing. Reported concerns were airflow obstruction while bending, hearing difficulties attributed to ventilation noise, and adjustments for headgear, ventilation, and suit fitting.
CONCLUSION
Test users confirmed the usability of smartPPE and favoured it, especially for doffing-safety, longer-interval clinical or physical work, and improved non-verbal interactions, whereas hearing was challenged by the ventilation. Adjustments are currently underway before design freeze. Stakeholder commitment will be crucial to ensure production at scale.
There is a lack of empirical data on design effects (DEFF) for mortality rate for highly clustered data such as with Ebola virus disease (EVD), along with a lack of documentation of methodological limitations and operational utility of mortality estimated from cluster-sampled studies when the DEFF is high.
OBJECTIVES
The objectives of this paper are to report EVD mortality rate and DEFF estimates, and discuss the methodological limitations of cluster surveys when data are highly clustered such as during an EVD outbreak.
METHODS
We analysed the outputs of two independent population-based surveys conducted at the end of the 2014-2016 EVD outbreak in Bo District, Sierra Leone, in urban and rural areas. In each area, 35 clusters of 14 households were selected with probability proportional to population size. We collected information on morbidity, mortality and changes in household composition during the recall period (May 2014 to April 2015). Rates were calculated for all-cause, all-age, under-5 and EVD-specific mortality, respectively, by areas and overall. Crude and adjusted mortality rates were estimated using Poisson regression, accounting for the surveys sample weights and the clustered design.
RESULTS
Overall 980 households and 6,522 individuals participated in both surveys. A total of 64 deaths were reported, of which 20 were attributed to EVD. The crude and EVD-specific mortality rates were 0.35/10,000 person-days (95%CI: 0.23-0.52) and 0.12/10,000 person-days (95%CI: 0.05-0.32), respectively. The DEFF for EVD mortality was 5.53, and for non-EVD mortality, it was 1.53. DEFF for EVD-specific mortality was 6.18 in the rural area and 0.58 in the urban area. DEFF for non-EVD-specific mortality was 1.87 in the rural area and 0.44 in the urban area.
CONCLUSION
Our findings demonstrate a high degree of clustering; this contributed to imprecise mortality estimates, which have limited utility when assessing the impact of disease. We provide DEFF estimates that can inform future cluster surveys and discuss design improvements to mitigate the limitations of surveys for highly clustered data.