The recent outbreak of the Coronavirus disease 2019 (COVID-19) has quickly spread worldwide since its discovery in Wuhan city, China in December 2019. A comprehensive strategy, including surveillance, diagnostics, research, clinical treatment, and development of vaccines, is urgently needed to win the battle against COVID-19. The past three unprecedented outbreaks of emerging human coronavirus infections at the beginning of the 21st century have highlighted the importance of readily available, accurate, and rapid diagnostic technologies to contain emerging and re-emerging pandemics. Real-time reverse transcriptase-polymerase chain reaction (rRT-PCR) based assays performed on respiratory specimens remain the gold standard for COVID-19 diagnostics. However, point-of-care technologies and serologic immunoassays are rapidly emerging with high sensitivity and specificity as well. Even though excellent techniques are available for the diagnosis of symptomatic patients with COVID-19 in well-equipped laboratories; critical gaps still remain in screening asymptomatic people who are in the incubation phase of the virus, as well as in the accurate determination of live viral shedding during convalescence to inform decisions for ending isolation. This review article aims to discuss the currently available laboratory methods and surveillance technologies available for the detection of COVID-19, their performance characteristics and highlight the gaps in current diagnostic capacity, and finally, propose potential solutions. We also summarize the specifications of the majority of the available commercial kits (PCR, EIA, and POC) for laboratory diagnosis of COVID-19.

The Epstein–Barr virus (EBV) is a DNA lymphotropic herpesvirus and the causative agent of infectious mononucleosis. EBV is highly prevalent since it affects more than 90% of individuals worldwide and has been linked to several malignancies including PTLDs, which are one of the most common malignancies following transplantation. Among all the EBV genes, most of the recent investigations focused on studying the LMP-1 oncogene because of its high degree of polymorphism and association with tumorigenic activity. There are two main EBV genotypes, Type 1 and 2, distinguished by the differences in the EBNA-2 gene. Further sub genotyping can be characterized by analyzing the LMP-1 gene variation. The virus primarily transmits through oral secretions and persists as a latent infection in human B-cells. However, it can be transmitted through organ transplantations and blood transfusions. In addition, symptoms of EBV infection are not distinguishable from other viral infections, and therefore, it remains questionable whether there is a need to screen for EBV prior to blood transfusion. Although the process of leukoreduction decreases the viral copies present in the leukocytes, it does not eliminate the risk of EBV transmission through blood products. Here, we provide a review of the EBV epidemiology and the genetic variability of the oncogene LMP-1. Then, we underscore the findings of recent EBV seroprevalence and viremia studies among blood donors as a highly prevalent transfusion transmissible oncovirus.

Background: The recent outbreak of the coronavirus disease 2019 (COVID-19) has quickly spread globally since its discovery in Wuhan, China, in December 2019. A comprehensive strategyincluding surveillance, diagnostics, research, and clinical treatmentis urgently needed to win the battle against COVID-19. Recently, numerous studies have reported the incidence of SARS-CoV-2 in asymptomatic patients. Yet, the incidence and viral transmission from the asymptomatic cases are not yet apparent. Aim: To estimate the incidence of COVID-19 among asymptomatic cases and describe its epidemiological and clinical significance this review systematically examined the published literature on SARS-CoV-2 in asymptomatic patients. Methods: The literature was searched through four scientific databases: PubMed, Web of Science, Scopus, and Science Direct. Results: Sixty-three studies satisfied the inclusion criteria. The majority of the reported studies were from China. However, there was a lack of SARS-CoV-2 epidemiological studies, from several countries worldwide, tracing the actual incidence of COVID-19, especially in asymptomatic patients. Studies with a large sample size (>1000) estimated that the percentage of people contracting SARS-CoV-2 and likely to be asymptomatic ranged from 1.2-12.9%. However, other studies with a smaller sample size reported a much higher incidence and indicated that up to 87.9% of COVID-19 infected individuals could be asymptomatic. Most of these studies indicated that asymptopatics are a potential source of infection to the community. Conclusion: This review highlighted the need for more robust and well-designed studies to better estimate COVID-19 incidence among asymptomatic patients worldwide. Early identification of asymptomatic cases, as well as monitoring and tracing close contacts, could help in mitigating the spread of COVID-19.

Hepatitis E virus (HEV) is an RNA virus that is an important cause of both acute and chronic hepatitis worldwide. To date, there are eight HEV genotypes that can infect mammals. HEV-1 and HEV-2 infect exclusively humans, while HEV-3 and HEV-4 infect humans and various animals, mainly pigs and deer. Additionally, two new genotypes (HEV-5 and HEV-6) infect mainly wild boar. Recently, newly discovered genotypes HEV-7 and HEV-8 were found to infect camels and possibly humans. Nevertheless, the epidemiological distribution of HEV-7 is not well established. HEV-8 is another newly discovered genotype that was identified in 2016 in Chinese Bactrian camels. Although faecal-oral transmission is the most common route of HEV transmission, HEV can be vertically transmitted from infected mothers to their fetuses. HEV may also spread by zoonotic transmission from infected animals to humans and through person-to-person contact. Nowadays, since the number of reported cases linked to blood donations is increasing annually, HEV is recognized as a transfusion-transmitted virus. Laboratory diagnostic techniques vary in their specificity and sensitivity for HEV detection. Direct techniques allow for detection of the viral proteins, antigens and viral nucleic acid, while HEV-specific IgG and IgM antibodies can help establish a diagnosis in acute and chronic infections. In this review, we will discuss recent technologies in the laboratory diagnosis of HEV, including serological and molecular methods to assess the specificity and sensitivity of currently available HEV commercial assays.

To support the deployment of serology assays for population screening during the COVID-19 pandemic, we compared the performance of three fully automated SARS-CoV-2 IgG assays: Mindray CL-900i® (target: spike [S] and nucleocapsid [N]), BioMérieux VIDAS®3 (target: receptor-binding domain [RBD]) and Diasorin LIAISON®XL (target: S1 and S2 subunits). A total of 111 SARS-CoV-2 RT-PCR- positive samples collected at ≥ 21 days post symptom onset, and 127 pre-pandemic control samples were included. Diagnostic performance was assessed in correlation to RT-PCR and a surrogate virus-neutralizing test (sVNT). Moreover, cross-reactivity with other viral antibodies was investigated. Compared to RT-PCR, LIAISON®XL showed the highest overall specificity (100%), followed by VIDAS®3 (98.4%) and CL-900i® (95.3%). The highest sensitivity was demonstrated by CL-900i® (90.1%), followed by VIDAS®3 (88.3%) and LIAISON®XL (85.6%). The sensitivity of all assays was higher in symptomatic patients (91.1–98.2%) compared to asymptomatic patients (78.4–80.4%). In correlation to sVNT, all assays showed excellent sensitivities (92.2–96.1%). In addition, VIDAS®3 demonstrated the best correlation (r = 0.75) with the sVNT. The present study provides insights on the performance of three fully automated assays, which could help diagnostic laboratories in the choice of a particular assay according to the intended use.

Human cytomegalovirus (CMV) is a highly prevalent herpesvirus worldwide. According to the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO), CMV infects people of all ages, and by the age of five, approximately one-third of children in the United States are infected. Although the infection is generally asymptomatic, it can cause severe disease in immunocompromised patients, transplant and transfusion recipients, as well as newborn neonates. The objective of this study is to systematically review published literature on CMV in the MENA region to estimate its incidence in the region and describe its epidemiological and clinical significance. The literature was searched through four scientific databases: PubMed, Scopus, Science Direct, and Web of Science. A total of 72 studies from 11 countries satisfied the inclusion criteria, covering a period from 1988–2019. The CMV IgG seroprevalence ranged from 8.7%–99.2% (SD = 38.95%). CMV incidence in these countries ranged between 1.22% and 77% in transplant and transfusion recipients, with an increase in incidence with advanced age. However, the incidence rate was unclear for congenital CMV due to the variability of the reporting. This review highlights the need for more robust and well-designed studies to better estimate CMV incidence in the MENA region, standardize diagnostic criteria, and consider prophylactic and pre-emptive treatments to limit the morbidity and mortality of the disease.

Highlights Performances of five commercial ELISA (EDI, AnshLabs, Dia.Pro, NovaTec, and Lionex) for detecting anti-SARS-CoV-2 IgG was evaluated. Samples used in this study are from diverse national background and the negative group contains samples that are seropositive for all other HCoV. All assays showed low sensitivity during the early stages (≤7 from symptom onset); however, it was greatly improved overtime. Lionex showed the highest specificity (98.6%), followed by EDI and Dia.Pro (97.1%,), NovaTec (85.7%), and AnshLabs (75.7%). Lionex, which measures antibodies to the S1 protein, demonstrated the best performance and doesn’t cross-react with any other HCoV.

Hepatitis E virus (HEV) is an RNA virus with 4 main genotypes. HEV-1 and HEV-2 infect solely humans, while HEV-3 and HEV-4 infect humans and various animals such as pigs, deer, and rabbits. HEV-5 and HEV-6 infect mainly wild boar. Recently, new genotypes, known as HEV-7 and HEV-8, were found to infect camels and humans. HEV is globally distributed into different epidemiological patterns based on socioeconomic factors and ecology. Although HEV is mainly transmitted through the fecal-oral route, it was also recognized as a transfusion-transmitted virus. Transmission through blood donation was documented worldwide with rising annual observations, accounting for more than 2.5% of all transmissions. HEV infection is usually asymptomatic or subclinical in immunocompetent individuals, so it remains questionable whether there is an urgent need to screen for HEV prior to blood transfusion. Moreover, recent studies conducted in the Middle East and North Africa (MENA) region indicate that HEV is highly endemic. Here, we provide a review on HEV epidemiology, transmission, and laboratory diagnosis, giving special emphasis to the newly discovered genotypes, HEV-7 and HEV-8. Furthermore, we underscore the findings of recent HEV seroprevalence and viremia studies among blood donors worldwide. We also shed light on similar studies performed among blood donors in the MENA region.