Volume 03 · Issue 04 · 2021

To monitor the presence of enteric pathogens in imported seafood, a total of 140 seafood samples imported from eight overseas countries were collected from Beijing, Dalian, Shanghai, Guangzhou, and Wuhan seafood markets from June to November 2019. Additionally, 116 viral, environmental swab samples were also collected from the Wuhan and Guangzhou seafood markets. Five typical enteric bacterial pathogens (Aeromonas spp., Shigella spp., Salmonella spp., Vibrio spp., and Listeria monocytogenes) and four viruses (Rotavirus, Norovirus, Astrovirus, and Sapovirus) were detected positive. Results showed that eight Vibrio parahaemolyticus isolates appeared in seafood imported to Dalian, Wuhan, Shanghai, Guangzhou, and Beijing. In contrast, Vibrio fluvialis and Aeromonas were isolated in another two samples. Norovirus was detected in one oyster sample imported from France and environmental surface in Guangzhou. The remaining pathogens were negative in all the samples being tested. With 120 V. parahaemolyticus isolates from the above countries, the genomic analysis revealed that sequence type ST1152 isolates imported from Canada were clustered with two V. parahaemolyticus isolates from Canada. This study presented the first microbiological analysis of the Wuhan seafood market before the outbreak of COVID-19, which demonstrated that supervision should be strengthened to prevent enteric pathogens via imported seafood.

The global spread of SARS-CoV-2 is currently continuing, and the World Health Organization has announced the risk assessment of the viruses as high. In this study, we analyzed virology features of SARS-CoV-2 causing a family cluster outbreak. Among the six family members, five have been laboratory-confirmed infection of SARS-CoV-2 viruses. A total of five SARS-CoV-2 viruses have been isolated from the nasopharyngeal swabs. The complete genome of the viruses exhibited 100% nucleotide identity with each other. Only two nucleotide differences have been observed between genomes of the isolated viruses and the HCoV/Wuhan/IVDC-HB-01/2019 strain. Therefore, SARS-CoV-2 has been confirmed as the causation of the family cluster infections.

Chronic hepatitis B virus (HBV) infection is a global public health problem, which can cause chronic hepatitis, liver cirrhosis, hepatocellular carcinoma (HCC), and other diseases. Antiviral therapy is the most critical measure to slow down the progression of chronic hepatitis B, prevent or delay cirrhosis, HCC, and other kinds of liver decompensation events. At present, the anti-hepatitis B virus drugs are mainly nucleoside (acid) analogues (NAs) and interferon. Each kind of antiviral drug has different effects on the clinical outcome of hepatitis B patients (such as HCC). In this paper, we discussed the biological characteristics, natural course and prognosis of HBV infection, the mechanism of HBV-related HCC, the effect of different antiviral drugs on patients’ outcome, predictive biomarkers and model for HBV clinical outcome, predictors of sustained response and recurrence after withdrawal of antiviral therapy, consideration of expanding therapeutic indications and antiviral therapy, hoping to give a hand to the clinical diagnosis and treatment of HBV.

Brucellosis is a zoonotic disease caused by a number of bacteria in the genus Brucella. In animals, classical Brucella species naturally affiliate with mammals in which they cause epididymitis and orchitis in males and abortion storms in pregnant females. Because Brucella proliferates to a vast number of free organisms in the fetal organs and fluids, abortion plays a key mechanism in disease spread in nature. B. melitensis, B. suis, and B. abortus construct the three most severe zoonotic species and their role in human brucellosis stems from their association with domesticated farm animals in which they strive and transmit the disease. Here we review the relevant literature on genus Brucella, vaccination and diagnostic approaches. Meanwhile, the prevention and control programs based on the combination of vaccination coverage of the population with differentiating serological diagnosis of the infected from vaccinated animals (DIVA) and herd clearance by a test and cull strategy using validated serological tests were discussed.

The pandemic of coronavirus disease 2019 (COVID-19) has already evoked massive influence. The global pandemic has been ravaging the whole world for a year, with the number of confirmed human infection cases over 150 million and a death toll exceeding 3 million. Although the genomic sequence of the cognate pathogen SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) has been quickly determined, there are still many unknown aspects, including the virus origin and evolution trend, and the effectiveness of current vaccines and drugs against the mutating virus. This review summarizes current knowledge and advances about COVID-19, including virus origin, transmission and infection, with the aim to improve the understanding of COVID-19 and provide a new perspective for future studies.

The emerging Babesia venatorum upsurges as a potential health threat occurring in China and other endemic countries. Few attempts to isolate and culture the Babesia species had been conducted in vitro. We collected the questing Ixodes persulcatus from identified endemic areas and allowed them to feed on the severe combined immunodeficiency (SCID) mice. The positive mice were chosen to provide positive erythrocytes with asexual B. venatorum for continuous culture in mouse or human erythrocytes in vitro, with RPMI 1640 medium and appropriate serum. With B. venatorum in the SCID mice, erythrocytes were cultured in vitro for confirmation by morphological observations with transmission electron microscopes. Sequences of B. venatorum were then identified by way of conventional PCR amplification. Parasitemia counts monitored the growth of B. venatorum on thin blood smears and real-time quantitative PCR in parallel. As expected, B. venatorum positive mice were harvested by sufficient attacks of I. persulcatus ticks. The erythrocytes of the infected mice were then inoculated and successfully cultured in donated erythrocytes from humans and mice in RPMI 1640 culture medium. Active growth of B. venatorum was well demonstrated in human erythrocytes with 3.3 times parasite-load when compared with a mouse under similar conditions. With the increased subcultures, a prolonged period of detectable parasitemia with much higher peak parasitemia and shorter time to reach peak parasitemia were observed in the following subcultures. A new strategy for isolation and in vitro culture of B. venatorum has been provided with a continuous supply of sufficient pathogens to satisfy human babesiosis's testings and clinical therapies.

Foot-and-mouth disease virus (FMDV), swine vesicular disease virus (SVDV) and classical swine fever virus (CSFV) all cause important animal diseases. FMDV affects many different cloven-hoofed animals, whereas SVDV and CSFV are restricted to domestic and feral pigs together with wild boar. Europe is normally free of these diseases, but occasionally outbreaks happen, which can cause huge economic losses. Handling of these viruses, in particular FMDV and CSFV, is only allowed within high containment laboratories and stables. Periodically such facilities need to be decommissioned for repair or closing down, which is done by cleaning and chemical disinfection, followed by fumigation due to residual risk from virus on surfaces in inaccessible places. However, building materials in older laboratories or stables that have housed infected animals may not be well-suited for fumigation. Heat treatment is another way of inactivating viruses. In this study, we have determined the survival of infectivity in air-dried virus samples on glass and plastic surfaces incubated at room temperature or heated to 70 °C for 1, 2, 3, 5 and 7 days. Each of the tested viruses was inactivated to below the limit of detection after 24 h or 48 h of incubation at 70 °C; in contrast, some of these viruses were still infectious after 7 days of incubation at room temperature. This study provides important information that can be used in relation to decontamination of buildings and in risk-assessments.

This study aims to evaluate the biosafety awareness of laboratory staff working on pathogens detection in seven Centers for Disease Control and Prevention and support these staff's biosafety management and training. A total of 208 laboratory staff from seven provincial CDCs were chosen by stratified random sampling to undergo a self-administered questionnaire survey. The collected data were analyzed using SPSS 22.0. The overall average biosafety awareness of the CDC laboratory staff involved in pathogen detection was 82.5 points. The average biosafety awareness score was the highest in health monitoring (92.63 points) and the lowest in risk assessment and control (41.6 points). Among the seven provincial CDCs, the Guizhou Provincial Center for Disease Control and Prevention laboratory staff showed the lowest average biosafety awareness score (74.3 points). The team who worked for 5-14 years were more likely to score above the passing score (≥88 points; corrected OR 0.400, 95%CI: 0.168-0.951) than the staff with less than five years of work experience. In addition, the mid-level and junior-level staff, as well as the lower position ones were more likely to score below the passing score (<88 points; junior level and lower: corrected OR 3.473, 95%CI: 1.028-11.737; mid-level: corrected OR 2.797, 95%CI: 1.027-7.618) compared with the senior-level staff. Among the surveyed team, 66.3% identified a lack of specific funds related to work, 61.5% identified a lack of designated personnel for the laboratory biosafety management. The biosafety awareness in CDC laboratory staff involved in pathogen detection is low, especially regarding risk assessment and control. The biosafety awareness in Guizhou and Guangxi Provincial CDC laboratory staff is also low. Laboratory funding, job title, and years of experience in a laboratory influence biosafety awareness in CDC laboratory staff. The biosafety knowledge, education, and training of CDC laboratory staff involved in pathogen detection need to improve by paying attention to the content and coverage of biosafety training, exploring new training modalities, and increasing funding for activities related to biosafety in CDC.

In malaria-endemic regions, people often get exposed to various pathogens simultaneously, generating co-infection scenarios. In such scenarios, overlapping symptoms pose serious diagnostic challenges. The delayed diagnosis may lead to an increase in disease severity and catastrophic events. Recent coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected various areas globally, including malaria-endemic regions. The Plasmodium and SARS-CoV-2 co-infection and its effect on health are yet unexplored. We present a case report of a previously healthy, middle-aged individual from the malaria-endemic area who suffered SARS-CoV-2 and Plasmodium falciparum co-infection. The patient developed severe disease indications in a short time period. The patient showed neurological symptoms, altered hematological as well as liver-test parameters, and subsequent death in a narrow time span. We hereby discuss the various aspects of this case regarding treatment and hematological parameters. Further, we have put forward perspectives related to the mechanism behind severity and neurological symptoms in this fatal parasite-virus co-infection case. In malaria-endemic regions, due to overlapping symptoms, suspected COVID-19 patients should also be monitored for diagnosis of malaria without any delay. The SARS-CoV-2 and Plasmodium co-infection could increase the disease severity in a short time span. In treatment, dexamethasone may not help in severe cases having malaria as well as COVID-19 positive status and needs further exploration.