Chikungunya virus ; genetics ; isolation & purification ; China ; Genome, Viral ; RNA, Viral ; genetics ; Sequence Analysis, RNA

OBJECTIVETo explore a convenient and effective method for norovirus nucleic acid extraction from oysters suitable for long-term viral surveillance.

METHODSTwo methods, namely method A (glycine washing and polyethylene glycol precipitation of the virus followed by silica gel centrifugal column) and method B (protease K digestion followed by application of paramagnetic silicon) were compared for their performance in norovirus nucleic acid extraction from oysters. Real-time RT-PCR was used to detect norovirus in naturally infected oysters and in oysters with induced infection.

RESULTSThe two methods yielded comparable positive detection rates for the samples, but the recovery rate of the virus was higher with method B than with method A.

CONCLUSIONMethod B is a more convenient and rapid method for norovirus nucleic acid extraction from oysters and suitable for long-term surveillance of norovirus.

Animals ; Centrifugation ; methods ; Norovirus ; genetics ; isolation & purification ; Ostreidae ; virology ; RNA, Viral ; isolation & purification

OBJECTIVETo compare the results of detecting HIV-1 load by using NucliSens HIV-1 QT and Amplicor HIV-1 monitor 1.5 assays.

METHODSEighty-two clinical samples were collected and HIV viral load was determined with the above-mentioned two methods.

RESULTSThe number of samples in which values obtained by NucliSens HIV-1 QT and Amplicor HIV-1 monitor 1.5 differed by <0.5 log10 RNA copies/ml and in which the viral load was undetectable accounted for 88.9 percent of the measures. The correlation coefficient between the two methods was 0.956 in 56 samples of Deltalog10 VL<0.5.

CONCLUSIONThe results of HIV-1 viral load determination with the two methods are highly comparable.

HIV Infections ; virology ; HIV-1 ; genetics ; isolation & purification ; Humans ; Nucleic Acid Amplification Techniques ; instrumentation ; methods ; RNA, Viral ; genetics ; Viral Load

OBJECTIVETo study the genetic characterization of wild-type measles viruses isolated in Xinjiang in 2003 and 2004.

METHODSPeripheral blood mononuclear cells (PBMC) from 19 suspected measles cases collected between June 2003 and April 2004 were used to isolate measles virus by cocultivation with phytohemagglutinin (PHA)-stimulated cord blood mononuclear cells (CBMC). For positive samples, 676 nucleotides of the C-terminus of the nucleoprotein (N) gene of the measles virus genome were amplified by reverse transcription-polymerase chain reaction and then sequenced. These sequences were compared with those of other measles reference strains available in GenBank or measles isolates elsewhere in China using BLAST searches and phylogenetic analyses.

RESULTS6 measles virus strains were isolated with 3 strains (XJ03-26, XJ03-27, XJ03-74) from 2003 and 3 (XJ04-146, XJ04-150, XJ04-152) from 2004. The strain XJ03-26, differed from the Chinese measles vaccine strain S-191 (genotype A) by less than 1% at nucleotide level, and therefore appeared a vaccine-associated strain. The other 5 strains as XJ03-27, XJ03-74, XJ04-146, XJ04-150 and XJ04-152 were proved to be genotype H1 strains,among which XJ03-27, XJ03-74, XJ04-150 and XJ04-152, showing their nucleotide diversity were varied from 0.5% to 1.6%, when compared to the H1a reference strain China9322, and identified as H1a strains. XJ04-146 showed a nucleotide similarity of 98.7% when compared to H1b reference strain China9475, and was identified as H1b strain. Additionally, we found that there were two sets of strain (XJ03-27 and XJ04-150; XJ03-74 and XJ04-152), with almost identical nucleotide sequences, circulating in 2003 and 2004 and both having more nucleotide variability (up to 6.1%, 27 nucleotides).

CONCLUSIONGenotype H1 measles virus had been proven to have been circulated in Xinjiang, China during 2003 and 2004. H1a was the predominant epidemic strain while H1b strain stood the next.

China ; epidemiology ; Disease Outbreaks ; Genotype ; Humans ; Measles ; epidemiology ; Measles virus ; classification ; genetics ; isolation & purification ; Nucleoproteins ; genetics ; Phylogeny ; RNA, Viral ; genetics ; Sequence Analysis, RNA ; Viral Proteins ; genetics

Adult ; Antibodies, Viral/isolation & purification* ; COVID-19/virology* ; Feces/chemistry* ; Female ; Humans ; Intestines/virology* ; Male ; RNA, Ribosomal, 16S/genetics* ; RNA, Viral/isolation & purification* ; SARS-CoV-2/pathogenicity*

OBJECTIVE: Tick-borne encephalitis virus (TBEV) is an emerging pathogen in Europe and North Asia that causes tick-borne encephalitis (TBE). A simple, rapid method for detecting TBEV RNA is needed to control this disease. METHODS: A reverse-transcription recombinase-aided amplification (RT-RAA) assay was developed. This assay can be completed in one closed tube at 39 °C within 30 minutes. The sensitivity and specificity of RT-RAA were validated using non-infectious synthetic RNA representing a fragment of the NS5 region of the wild-type (WT) TBEV genome and the Senzhang strain. Additionally, 10 batches of tick samples were used to evaluate the performance of the RT-RAA assay. RESULTS: The analytical limit of detection of the assay was 20 copies per reaction of the TBEV synthetic transcript and 3 plaque-forming units (pfu) per reaction of TBEV titers. With the specific assay, no signal due to other arboviruses was observed. Of the 10 batches of tick samples obtained from the Changbai Mountains of China, three were TBEV-positive, which was consistent with the results of the quantitative real-time PCR assay. CONCLUSION A rapid, highly sensitive, specific, and easy-to-use method was developed for the detection of the TBEV Far-Eastern subtype.
Encephalitis Viruses, Tick-Borne ; genetics ; isolation & purification ; Nucleic Acid Amplification Techniques ; RNA, Viral ; analysis

OBJECTIVETo compare the molecular characteristics of 3 Crimean-Congo hemorrhagic fever viruses(CCHFV) isolated in Xinjiang province.

METHODSYL05035, YT05099 and LT05146 were isolated in 2005 from Hyalomma ticks and viral RNA was extracted from suckling mouse brains infected with these three strains respectively. The polymerase chain reaction(PCR) products of S segments from the 3 strains of CCHFV were directly sequenced.

RESULTSThe full-length'S RNA from the 3 strains of CCHFV all comprised 1673 nucleotides with ORF of them including 1449 nucleotides and encoding a protein which comprised 482 amino acids in a viral complementary sense. The sequences indicated that the three strains of CCHFV isolated from ticks in Xinjiang province were highly homologenic. Data from the phylogenetic analysis showed that the obtained sequences were identical. The homology between 3 strains of CCHFV was 99.5%. Their homologies compared with that of the other strains isolated from other region of Xinjiang were also high at nucleotide levels (92.7%-99.8%). The three strains which were clustered together with 7001 strain and 79121 strain (isolated from patient and rat in Xinjiang respectively) was only different by 2%-3%. The genetic difference from the prototype CCHFV Nigerian strain IBAR10200 was 13%. In comparison, the Nigerian CCHFV tick isolate was more divergent when compared with the reference China strains 66019 and with the three variants mentioned above.

CONCLUSIONThe CCHFV isolated from China comprised a group of genetically high conserved strains.

Animals ; Brain ; virology ; China ; Genes, Viral ; Hemorrhagic Fever Virus, Crimean-Congo ; genetics ; isolation & purification ; Mice ; RNA, Viral ; analysis

OBJECTIVETo investigate the gene variations of influenza B virus isolated in Hunan province from 2007 to 2010.

METHODSA total of 42 strains of influenza B virus,which were isolated in the Influenza Surveillance Network Laboratories in Hunan province between year 2007 and 2010, were selected for the study. The hemagglutinin 1 (HA1) and neuraminidase (NA) genes of the selected strains were amplified by RT-PCR, and the sequence of the purified product were detected and homologically compared with the sequence of influenza vaccine strains isolated from Northern Hemisphere by WHO during the same period. In addition, the phylogenetic trees were constructed to characterize the molecular features.

RESULTSIn the Victoria branch of the HA1 gene phylogenetic tree, the strains isolated from year 2007 to 2009 were included in the V1 sub-branch, as well as the vaccine strain Malaysia/2506/2004; the strains isolated in year 2010 were involved in the V2 sub-branch, similar to the vaccine strains Brisbane/60/2008. In the Yamagata branch,the strains isolated in year 2007 were in the Y1 sub-branch,different from the strains isolated between year 2008 and 2010, which were in the Y2 sub-branch, instead. All virus in NA gene phylogenetic tree were included in the Yamagata branch, indicated their Yamagata origin. The genetic sequence analysis of the 7 strains isolated in year 2010 revealed that the viruses were classified as genotype 2 and genotype 15. The results of homological comparison between HA1 molecule and the influenza vaccine strains recommended by WHO were as below: Victoria lineage, 98.6% - 99.1% in 2007, 98.6% - 99.1% in 2008, 98.1% - 99.1% in 2009, and 97.6% - 99.1% in 2010; and Yamagata lineage, 97.9% - 98.5% in 2007, 97.9% - 98.5% in 2009 and 97.9% - 98.2% in 2010. The major mutations of the strains isolated in year 2007 were found in sites R48K, K88R, P108A, D197N and S230G. While the major mutations of the strains isolated between year 2009 and 2010 were sited in K88R, S150I, N166Y, D197N and S230G.

CONCLUSIONThe prevalent influenza B virus isolated in Hunan province from 2007 to 2010 has mutated and evolved continuously.

China ; epidemiology ; Genes, Viral ; Humans ; Influenza B virus ; genetics ; isolation & purification ; Influenza, Human ; epidemiology ; virology ; Phylogeny ; RNA, Viral ; Sequence Homology

A one step reverse transcription PCR (RT-PCR) combined nested PCR was set up to increase efficiency in the diagnosis of canine distemper virus (CDV) infection after developement of nested PCR. Two PCR primer sets were designed based on the sequence of nucleocapsid gene of CDV Onderstepoort strain. One-step RT-PCR with the outer primer pair was revealed to detect 10(2) PFU/ml. The sensitivity was increased hundredfold using the one-step RT-PCR combined with the nested PCR. Specificity of the PCR was also confirmed using other related canine virus and peripheral blood mononuclear cells (PBMC) and body secretes of healthy dogs. Of the 51 blood samples from dogs clinically suspected of CD, 45 samples were revealed as positive by one-step RT-PCR combined with nested PCR. However, only 15 samples were identified as positive with a single one step RT-PCR. Therefore approximately 60% increase in the efficiency of the diagnosis was observed by the combined method. These results suggested that one step RT-PCR combined with nested PCR could be a sensitive, specific, and practical method for diagnosis of CDV infection.
Animals ; Distemper Virus, Canine/genetics/*isolation & purification ; Dogs ; Polymerase Chain Reaction/*methods/*veterinary ; RNA, Viral/genetics/isolation & purification ; Reverse Transcriptase Polymerase Chain Reaction ; Vaccines, Attenuated ; Viral Vaccines

OBJECTIVE: To compare the diagnostic efficacy among three RT-PCR test kits for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid detection. METHODS: The throat swab samples from 40 hospitalized patients clinically diagnosed as coronavirus disease 2019 (COVID-19) and 16 hospitalized non-COVID-19 patients were recruited. The SARS-CoV-2 nucleic acid was detected in throat swab samples with RT-PCR test kits from Sansure Biotech ("Sansure" for short), Jiangsu Bioperfectus Technologies ("Bioperfectus" for short) and BGI Genomics ("BGI" for short). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and Kappa value were analyzed. The viral nucleic acid was extracted from the throat swab samples by one-step cleavage and magnetic bead methods, and the efficacy of two extraction methods was also compared. The results of magnetic bead method for nucleic acid extraction by two different extractors (Sansure Natch CS S12C Fully Automated Nucleic Acid Extraction System vs. Tianlong NP968-C Nucleic Acid Extractor) were also compared. RESULTS: The sensitivity, specificity, PPV, NPV and kappa value were 95.00%, 87.50%, 95.00%, 87.50%and 0.825 for Sansure kit; 90.00%, 87.50%, 94.74%, 77.78%and 0.747 for the Bioperfectus kit, and 82.50%, 81.25%, 91.67%, 65.00%and 0.593 for the BGI kit, respectively. The positive, negative and total coincident rates and kappa value of viral nucleic acid detection results using the samples extracted by one-step cleavage and magnetic bead methods were 95.24%, 100.00%, 96.43%and 0.909, respectively, but the one-step cleavage method took only 25 min, while the magnetic bead method required 180 min. The positive, negative and total coincident rates and kappa value of viral nucleic acid detection results using the samples extracted by the two different nucleic acid extractors were 85.00%, 100.00%, 89.29% and 0.764, respectively. CONCLUSIONS The detection efficacy for SARS-CoV-2 nucleic acid by the Sansure kit is relatively higher and the one-step cleavage method has advantages of convenient operation and less time consuming.
Betacoronavirus ; genetics ; isolation & purification ; Coronavirus Infections ; diagnosis ; virology ; Humans ; Pandemics ; Pneumonia, Viral ; diagnosis ; virology ; RNA, Viral ; genetics ; isolation & purification ; Reagent Kits, Diagnostic ; standards