Discordant SARS-CoV-2 PCR and Rapid Antigen Test Results When Infectious: A December 2021 Occupational Case Series

The performance of Covid-19 diagnostic tests must continue to be reassessed with new variants of concern. The objective of this study was to describe the discordance in saliva SARS-CoV-2 PCR and nasal rapid antigen test results during the early infectious period. We identified a high-risk occupational case cohort of 30 individuals with daily testing during an Omicron outbreak in December 2021. Based on viral load and transmissions confirmed through epidemiological investigation, most Omicron cases were infectious for several days before being detectable by rapid antigen tests.

Occurrence of Chicken Infectious Anemia Virus in Industrial and Backyard Tunisian Broilers: Preliminary Results

Chicken infectious anemia virus (CIAV) is an economically important and widely distributed immunosuppressive agent in chickens. This study performed an epidemiological investigation on CIAV circulation in 195 Tunisian broilers, belonging to 13 lots from five industrial farms and in one rural farm. Fifteen animals were detected positive by a VP1 nested PCR. The amplicons were molecularly characterised by complete genome sequencing. All positive samples obtained in this study were from the rural farm, whereas the industrial farms sampled were negative. Nucleotide and amino acid sequence analyses showed a high degree of similarity among the sequences obtained, suggesting the circulation of a single CIAV strain in the positive lot. Phylogenetic analysis based on the CIAV VP1 nucleotide sequence and/or the complete genome showed that the sequences obtained in this study clustered with CIAV strains previously detected in Tunisia, Italy and Egypt, belonging to genogroup II. Our results highlight the need for constant CIAV surveillance in backyard chicken production.

Epidemiological investigation for brucellosis in dogs of Thrissur

India is endemic to bovine brucellosis, and there is a high potential for transmission of disease from ruminants to dogs. A total of 18 bitches belonging to five different breeds at different stage of abortion (30 days to 65 days of gestation) were selected for this study. Majority of them were showing abortion (88.89 per cent) at 45 to 65 days of the gestation. Microscopic examination of Stamp stained smear obtained from the aborted foetal stomach contents revealed red coccobacillary organisms suggestive of Brucella spp.in three cases. RBPT on paired sera samples on day of presentation and three weeks after abortion showed agglutination within four minutes in five out of 18 female dogs. DNA extracted from the aborted tissues of a RBPT positive Labrador dog yielded amplicons of 193 base pair specific for Brucella spp. on PCR. The results obtained from this study stress the need for screening dogs for canine brucellosis in the current brucellosis surveillance and control programmes.

Outbreak of SARS-CoV-2 in hospitalized hemodialysis patients: an epidemiologic and genomic investigation

We performed an epidemiological investigation and SARS-CoV-2 genome sequencing to define the source and scope of an outbreak in a cluster of hospitalized patients. Lack of appropriate respiratory hygiene led to SARS-CoV-2 transmission to patients and healthcare workers during a single hemodialysis session, highlighting the importance of infection prevention precautions.

A Rare Case of Cysticercosis Involving the Whole Spinal Canal

Background Cysticercosis is the commonest parasitic disease to affect the central nervous system (CNS). However, cysticercosis affecting the spine is extremely rare. We reported a rare case of cysticercosis involving the whole spinal canal in China. Case Presentation A rare case of cysticercosis involving the entire spinal cord, in a 52-year-old Chinese man, was detected in 2021. Epidemiological investigation, clinical and etiological examination was performed. Conclusion Since spinal cysticercosis is a rare but potentially life-threatening disease, clinicians should always consider the differential diagnosis of space-occupying lesions.

Propagation of a hospital-associated cluster of COVID-19 in Malaysia

Background Hospitals are vulnerable to COVID-19 outbreaks. Intrahospital transmission of the disease is a threat to the healthcare systems as it increases morbidity and mortality among patients. It is imperative to deepen our understanding of transmission events in hospital-associated cases of COVID-19 for timely implementation of infection prevention and control measures in the hospital in avoiding future outbreaks. We examined the use of epidemiological case investigation combined with whole genome sequencing of cases to investigate and manage a hospital-associated cluster of COVID-19 cases. Methods An epidemiological investigation was conducted in a University Hospital in Malaysia from 23 March to 22 April 2020. Contact tracing, risk assessment, testing, symptom surveillance, and outbreak management were conducted following the diagnosis of a healthcare worker with SARS-CoV-2 by real-time PCR. These findings were complemented by whole genome sequencing analysis of a subset of positive cases. Results The index case was symptomatic but did not fulfill the initial epidemiological criteria for routine screening. Contact tracing suggested epidemiological linkages of 38 cases with COVID-19. Phylogenetic analysis excluded four of these cases. This cluster included 34 cases comprising ten healthcare worker-cases, nine patient-cases, and 15 community-cases. The epidemic curve demonstrated initial intrahospital transmission that propagated into the community. The estimated median incubation period was 4.7 days (95% CI: 3.5–6.4), and the serial interval was 5.3 days (95% CI: 4.3–6.5). Conclusion The study demonstrated the contribution of integrating epidemiological investigation and whole genome sequencing in understanding disease transmission in the hospital setting. Contact tracing, risk assessment, testing, and symptom surveillance remain imperative in resource-limited settings to identify and isolate cases, thereby controlling COVID-19 outbreaks. The use of whole genome sequencing complements field investigation findings in clarifying transmission networks. The safety of a hospital population during this COVID-19 pandemic may be secured with a multidisciplinary approach, good infection control measures, effective preparedness and response plan, and individual-level compliance among the hospital population.

Human serum albumin variants in China: a molecular epidemiological investigation and literature review

Background Bisalbuminemia is a hereditary and/or acquired abnormality characterized by a double albumin (ALB) band on serum protein electrophoresis. However, there have been no epidemiological investigations of ALB variants in Chinese populations. Methods This retrospective study examined 71,963 unrelated subjects from five provinces in southern China. ALB variants were screened by cellulose acetate electrophoresis at pH 8.6 and ALB mutations were confirmed by polymerase chain reaction-DNA sequencing. Results The average incidence of inherited bisalbuminemia in the southern Chinese population was 0.0264% (19/71,963). Thirteen cases showed slow and six showed fast genetic variants on cellulose acetate electrophoresis. Four kinds of ALB variants were identified: proalbumin Lille (p.Arg23His), ALB Castel di Sangro (p.Lys560Glu), ALB Fukuoka-1 (p.Asp587Asn), and a novel ALB Wuxi (p.Lys562Glu). The gene frequency of ALB variants in the Wuxi region (0.126%, 13/10,297) was significantly higher than in other regions in southern China, and 90.9% (10/11) of cases of proalbumin Lille were also found in the Wuxi region. Conclusions This study provides the first report of the detailed prevalence and molecular characterization of ALB variants in southern China. Compared with other areas of China, Wuxi had a different pattern of ALB variants and a high prevalence of proalbumin Lille.