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[Objective] To prepare broad-spectrum monoclonal antibody against N protein of avian infectious bronchitis virus (IBV), so as to lay a foundation for identifying conservative domain epitope of N protein and establish a universal IBV detection method. [Method] N protein of GX-YL5, a representative strain of IBV dominant serotype in Guangxi, was expressed in prokaryote. BALB/c mice were immunized with the purified protein. After the serum titer of the immunized mice reached 104 or more, the splenocytes were fused with SP2/0 myeloma cells. After screening by indirect ELISA, monoclonal antibody was prepared by ascites-induced method. Western blotting, IFA and indirect ELISA were used to identify the titer, subtype, reaction specificity and cross-reaction spectrum. And the prepared monoclonal antibody was used for immunohistochemical detection. And the prepared monoclonal antibody was used to detect the IBV in the trachea and kidney tissues of SPF chickens artificially infected with 4 representative IBV variants (GX-N130048, GX-N160421, GX-QZ171023 and GX-QZ170728). [Result] The prepared monoclonal antibody N2D5 had a titer greater than 217 and its subtype was IgG2b. The Western blotting and IFA results showed that the monoclonal antibody N2D5 only reacted with IBV, and were negative with Newcastle disease virus (NDV), infectious laryngotracheitis virus (ILTV), avian metapneumovirus (aMPV), infectious bursal disease virus (IBDV), avian leukosis virus (ALV) and Marek's disease virus (MDV). Monoclonal antibody N2D5 reacted with many genotypes in China and all 7 serotypes of IBV currently prevalent in Guangxi, including commonly used standard strains, vaccine strains and field strains. Immunohistochemistry showed that the virus signals could be detected in the trachea and kidney tissues of SPF chickens at different time after artificial infection of 3 representative IBV strains from chicken and 1 isolated strain from duck, which further proved its broad spectrum. [Conclusion] The monoclonal antibody N2D5 of IBV prepared based on hybridoma technology belongs to the IgG2b subtype. It has the characteristics of high specificity, wide response spectrum and strong binding ability with IBV. It can be used as a specific diagnostic antibody for clinical diagnosis of IBV and the study of virus distribution.
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Objective: To analyze the epidemiological characteristics of a local COVID-19 outbreak in Qinzhou, Guangxi Zhuang autonomous region, and provide reference for the prevention and control of COVID-19 in the future. Methods The epidemiological and clinical information, analysis reports and laboratory test results of the COVID-19 cases were collected for a descriptive epidemiological analysis. Results A total of 97 COVID-19 cases, including 79 asymptomatic cases and 18 confirmed cases, were reported in Qinzhou during 12-24 March, 2022. Forty nine cases were males and 48 cases were females. The median of age of the cases was 32 (17.0, 44.5) years. The median of incubation period was 3 days. The median of latent period was 2 days. A total of 3841 close contacts were screened, in whom 61 were infected. The secondary attack rates in 3841 close contacts was 1.59%. The secondary attack rate in household contacts was 65% in 8 family clustering (95% CL: 20%-100%). Three mass gathering were identified in a local recreation center box, a wedding ceremony and a family feast for new home, in which the attack rates were 63.64%, 9.38% and 12.16%, respectively. Transmission firstly occurred in the people attending the activity in the recreation center box. At least 5 generations of transmission were identified in the outbreak. The results of genome second generation sequencing of the isolates from 20 infection cases revealed that the pathogen of the outbreak was SARS-CoV-2 Omicron variant (BA.2). Conclusion Analysis on the cases caused by Omicron variant (BA.2) indicated early prevention measures are important for the control of further spread of COVID-19.
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Objective: To analyze the epidemiological characteristic and tracing process of an outbreak of COVID-19 in a sea-land border city (D city) of Guangxi in December 2021, and provide scientific data for for the emergency management and scientific traceability of similar outbreaks in the future. Methods Epidemiological investigation of cases was carried out under the guideline of the Novel Coronavirus Epidemiological Investigation Programme on Cases of Pneumonia (Edition 8). RT-PCR method was used for samples testing. Furthermore, positive samples were analyzed by whole-genome sequence and phylogenetic analysis. R software 4.1.3 version was used for data analysis. Results There were 20 cases in this outbreak which related 6 families. The average incubation period was (4.6..2.2) d. Compared with the Wuhan reference strain (NC_045512), the genome sequence analysis showed that there were 35-36 nucleotide mutation sites in the novel Coronavirus genome sequence of 19 local cases, which belonged to VOC/Delta variant strain (AY.57 evolutionary branch). The 11 amino acid mutation sites were the same in all the novel Coronavirus spikes (S) proteins, which were highly homologous to the 2 COVID-19 genome sequences uploaded from a neighboring country in the GISAID genome database. Conclusion This outbreak was caused by fishermen who were infected by contacting with persons of neighboring country in the public sea area and causing located community transmission. The management of border villagers and the monitoring of epidemic strains should be strengthened to detect and deal with the outbreak as early as possible in the future.
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To analyze the epidemiological characteristics and related factors of norovirus in Guangxi from 2015 to 2020, and to provide scientific recommendations for norovirus prevention and control. Methods The foodborne diseases surveillance data were collected from 11 sentinel hospitals through the National Foodborne Disease Monitoring and Reporting System from 2015 to 2020. R software with version 4.0.3 was used for descriptive and statistical analysis, including epidemic curve, chi-square test, and trend chi-square and so on. Logistic regression was used to analyze norovirus-related factors, OR values and 95% confidence intervals were calculated respectively with the statistical test level of P < 0.05. Results There were 1 008 norovirus cases detected, with a detection rate of 12.75% (1 008/7 903). Children with age less than 5 years (OR=1.43, 95%CI: 1.13-1.82) and patients at age 20-45 (OR=1.45, 95%CI: 1.13-1.87) were high risk population. The detection rate was higher in autumn (OR=1.29, 95%CI: 1.08-1.53) but lower in summer (OR=0.67, 95%CI: 0.55-0.80). In addition, the tourist area (Guilin City) presented a higher detection rate than other areas (OR=1.41, 95%CI: 1.10-1.80). Aquatic products (OR=1.40, 95%CI: 1.03-1.91), meat and dairy products (OR=1.31, 95%CI: 1.06-1.61) were high-risk foods for norovirus infection. The prevention and control policies of COVID-19 can reduce the possibility of norovirus by 61% (OR=0.39, 95%CI: 0.31-0.49) showed a declining trend (Trend X2=85.33, P < 0.001). In addition, prolonged visit time can lead to 19%-23% decrease in the detection rate of norovirus (OR24-48 hours=0.81, 95%CI: 0.70-0.95;OR>48 hours=0.77, 95%CI: 0.63-0.93). Conclusions The epidemic of norovirus presented seasonal and regional distribution in Guangxi with a declining detection rate trend in diarrhea patients during recent 6 years. Young children were high-risk population in infection norovirus. The intake of seafood can increase the risk of norovirus infection. The prevention and control policies of COVID-19 can sharply decrease the possibility of infection norovirus. The monitoring of key foods such as seafood should be strengthened, and the early screening of suspected cases should be taken. The norovirus monitoring should be improved to ensure the health of the population.
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In order to understand the genomic characteristics and molecular genetic diversity of porcine epidemic diarrhea virus(PEDV) in Guangxi in recent years, 11 pairs of specific primers were designed to detect the whole genome of PEDV GXNN isolated from porcine diarrhea in Nanning, Guangxi, China, and similarity comparison, genetic evolution, gene variation and S gene recombination were also analyzed. The results showed that full length of the GXNN strain was 28 035 bp, had similar genomic characteristics with other PEDV isolates, about 96.4%-98.7% nucleotide similarity with different reference strains, and the nucleotide similarity of S, ORF3, M and N genes was 93.7%-98.9%, 90.9%-99.4%, 97.4%-99.7% and 95.6%-99.2%;the amino acid similarity of them was 92.9%-99.5%, 91.3%-99.1%, 97.4%-99.1% and 96.4%-99.5%. GXNN is closely related to most domestic isolates in recent years. Phylogenetic tree showed that GXNN closely related to most strains isolated in China recent years, belonged to GII-b subtype. However, it was low relatedness to classic vaccine strains, domestic early epidemic strains, foreign epidemic strains and Guangxi CH-GX-2015-750 A, they belong to different subtypes. Compared with the 5 vaccine strains, the S gene of GXNN stain has a large variation, by inserting amino acid Q at positions 118 844 and 905 sizes, four unique amino acid mutations in the core neutralizing epitope(COE)region and the main epitope region, and 14 mutations in other regions. 126 T/A, 199 A/V and 103 T/A site mutations of ORF3, M and N genes were happened at position 126, 4 D4 region and PN-D4 region, respectively. Recombination analysis revealed that there was a potential recombination region in the hypervariable region of S gene at 826-3 142 nt. This study successfully obtained the complete genome sequence of a PEDV strain, and analyzed its genetic variation and provided a reference for PEDV molecular epidemiology research and new vaccine development.
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Objective: Temporal distribution and clustering of the epidemic of coronavirus disease 2019 (COVID-19) in Guangxi were analyzed.
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To understand the genetic diversity of porcine deltacoronavirus(PDCo V) in Guangxi Province, clinical diarrhea samples were collected from suspected piglets in Guangxi Province from2017 to 2019, detected by RT-PCR for PDCoV, and the positive samples were used for amplification and sequence of S, M, N genes. Finally, 16 S, M and N gene sequences of PDCoV were obtained. Homology analysis showed that the S, M, N gene nucleotide identity among Guangxi strains were 95.8% -99.9%, 95.9%-100% and 97.9%-99.9%, respectively. The nucleotide identity of S, M and N genes among Guangxi strains and other reference strains were 95.1%-100%, 95.0%-100%and 96.3%-99.9%, respectively. Sequence alignment showed that S1 protein existed amino acid mutations and insertions, and there were some variations among different epidemic strains. Phylogenetic trees based on S, M and N genes obtained similar topological diagram and all strains could be divided into Group I, Group II and GroupIII, of which Group I came from USA, Japan and Korea, Group II came from China, and Group III came from China, Vietnam, Laos and Thailand. Most strains from Guangxi Province distributed in Group II, individual strain distributed in Group III and some strains formed a single small branch. The evolutionary rates of S, M and N genes of Guangxi strains and other reference strains were 2.57 x 10-4, 2.07 x 10-4, 1.70 x 10-4 substitutions/site/year, respectively, showing that the evolutionary rate of S gene was the fastest. The results indicated that the S, M, N genes of PDCo V strains from Guangxi Province had some variations and existed genetic diversity.
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Objectives: To examine the clinical characteristics, drug resistance, and factors influencing development of a pulmonary fungal infection in patients with severe respiratory diseases in order to provide a reference for clinical treatment.
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Objective: To analyze the differences between imported malaria before and during the COVID-19 epidemic in Nanning city, and to predict the imported malaria epidemic, so as to provide a basis for future prevention and control strategies. Methods Malaria case data in Nanning city from 2018 to 2021 were collected and divided into two groups. The data from January 1, 2018 to December 31, 2019 were classified as the routine period before COVID-19, and the data from January 1, 2020 to December 31, 2021 were classified as the COVID-19 period. Statistical software was used to analyze the differences between the two groups in basic information, overseas activities, species of infected Plasmodium, diagnosis and treatment. Results The age difference between the two groups was statistically significant (t=2.222, P < 0.05);There was significant difference in the proportion of overseas residence types between the two groups (P < 0.05);There was significant difference in the proportion of parasite species between the two groups (P < 0.05). The proportion of Plasmodium ovale in the COVID-19 period group was higher than that in the routine period group, and the proportion of Plasmodium falciparum was lower than that in the routine period group;There was no significant difference between the two groups in terms of gender proportion, current address category proportion, malaria proportion due to going out for gold, proportion of mild, moderate and severe disease degree, proportion of hospitalization, proportion of standardized treatment, proportion of whole course medication, proportion of cure and length of hospital stay. Conclusions The incidence of imported malaria in Nanning declined significantly during the period of COVID-19, and the proportion of Plasmodium falciparum infection decreased. It is necessary to be vigilant against the outbreak of imported malaria caused by the increase of inbound people with the progress of COVID-19 control.
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Objective: To understand and analyze the epidemic status and development trends of soil-transmitted nematodiasis in Guangxi Zhuang Autonomous Region (Guangxi), to provide scientific basis for formulating the disease control strategy, and evaluating the control effect.
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Objective: To investigate the efficacy of entecavir (ETV) versus tenofovir disoproxil fumarate (TDF) and the treatment measures for poor response in previously untreated chronic hepatitis B (CHB) patients with high viral load.