Coronavirus disease-2019 (COVID-19) pandemic has become a global threat and death tolls are increasing worldwide. The SARS-CoV-2 though shares similarities with SARS-CoV and MERS-CoV, immunopathology of the novel virus is not understood properly. Previous reports from SARS and MERS-CoV documents that preexisting, non-neutralizing or poorly neutralizing antibodies developed as a result of vaccine or infection enhance subsequent infection, a phenomenon called as antibody-dependent enhancement (ADE). Since immunotherapy has been implicated for COVID-19 treatment and vaccine is under development, due consideration has to be provided on ADE to prevent untoward reactions. ADE mitigation strategies like the development of vaccine or immunotherapeutics targeting receptor binding motif can be designed to minimize ADE of SARS-CoV-2 since full-length protein-based approach can lead to ADE as reported in MERS-CoV. The present mini-review aims to address the phenomenon of ADE of SARS-CoV-2 through the lessons learned from SARS-CoV and MERS-CoV and ways to mitigate them so as to develop better vaccines and immunotherapeutics against SARS-CoV-2.
The coronavirus disease 2019 (COVID-19) pandemic, which started in China, has created a panic among the general public and health care/laboratory workers. Thus far, there is no medication or vaccine to prevent and control the spread of COVID-19. As the virus is airborne and transmitted through droplets, there has been significant demand for face masks and other personal protective equipment to prevent the spread of infection. Health care and laboratory workers who come in close contact with infected people or material are at a high risk of infection. Therefore, robust biosafety measures are required at hospitals and laboratories to prevent the spread of COVID-19. Various diagnostic platforms including of serological, molecular and other advanced tools and techniques have been designed and developed for rapid detection of SARS-CoV-2 and each has its own merits and demerits. Molecular assays such as real-time reverse transcriptase polymerase chain reaction (rRT-PCR) has been used worldwide for diagnosis of COVID-19. Samples such as nasal swabs or oropharyngeal swabs are used for rRT-PCR. Laboratory acquired infection has been a significant problem worldwide, which has gained importance during the current pandemic as the samples for rRT-PCR may contain intact virus with serious threat. COVID-19 can spread to workers during the sampling, transportation, processing, and disposal of tested samples. Here, we present an overview on advances in diagnosis of COVID-19 and details the issues associated with biosafety procedures and potential safety precautions to be followed during collection, transportation, and processing of COVID-19 samples for laboratory diagnosis so as to avoid virus infection.
Brucella melitensis causes small ruminant brucellosis and a zoonotic pathogen prevalent worldwide. Whole genome phylogeny of all available B. melitensis genomes (n = 355) revealed that all Indian isolates (n = 16) clustered in the East Mediterranean lineage except the ADMAS-GI strain. Pangenome analysis indicated the presence of limited accessory genomes with few clades showing specific gene presence/absence pattern. A total of 43 virulence genes were predicted in all the Indian strains of B. melitensis except 2007BM-1 (ricA and wbkA are absent). Multilocus sequence typing (MLST) analysis indicated all except one Indian strain (ADMAS-GI) falling into sequence type (ST 8). In comparison with MLST, core genome phylogeny indicated two major clusters (>70% bootstrap support values) among Indian strains. Clusters with <70% bootstrap support values represent strains with diverse evolutionary origins present among animal and human hosts. Genetic relatedness among animal (sheep and goats) and human strains with 100% bootstrap values shows its zoonotic transfer potentiality. SNP-based analysis indicated similar clustering to that of core genome phylogeny. Among the Indian strains, the highest number of unique SNPs (112 SNPs) were shared by a node that involved three strains from Tamil Nadu. The node SNPs involved several peptidase genes like U32, M16 inactive domain protein, clp protease family protein, and M23 family protein and mostly represented non-synonymous (NS) substitutions. Vaccination has been followed in several parts of the world to prevent small ruminant brucellosis but not in India. Comparison of Indian strains with vaccine strains showed that M5 is genetically closer to most of the Indian strains than Rev.1 strain. The presence of most of the virulence genes among all Indian strains and conserved core genome compositions suggest the use of any circulating strain/genotypes for the development of a vaccine candidate for small ruminant brucellosis in India.
In the present study efficacy of single intradermal Johnin test, acid fast staining of faecal smear and IS 900 faecal polymerase chain reaction tests was evaluated in 200 goats for detection of Mycobacterium avium subsp paratuberculosis. Two hundred goats comprising 150 goats from an organised farm in Trichur district and 50 goats reared under field condition at farmers premise from Malappuram district of Kerala state formed the study population. Faecal smear from all the 200 goats was stained by Ziehl-Neelsen acid fast stain and faecal polymerase chain reaction (PCR) specific for M. avium subsp paratuberculosis (MAP); IS 900 was performed on all samples. All the animals were subjected to single intradermal Johnin test. Out of 200 goats screened for paratuberculosis, six goats (3%), 11 goats (5.5%) and 42 goats (21%) were found positive by Ziehl-Neelsen acid fast staining of faecal smear, single intradermal Johnin test and IS 900 PCR respectively. Results of the present study indicate that amplification of IS 900 insertion element was the most specific and sensitive diagnostic detection method. Single intradermal Johnin test and Ziehl-Neelsen acid fast staining did not show any significant difference.
Globally, P. vannamei is the vital species in aquaculture production. Beneficial bacterial exploration of gut, sediment and water were investigated in P. vannamei culture using Illumina Miseq sequencing of 16S RNA V3-V4 hypervariable regions. Predominant phyla identified were Proteobacteria, Tenericutes, Bacteroidetes in gut; Proteobacteria, Bacteroidetes, Planctomycetes in sediment and Cyanobacteria, Proteobacteria and Planctomycetes in water. In total, 46 phyla, 509 families and 902 genera; 70 phyla, 735 families and 1255 genera; 55 phyla, 580 families and 996 genera were observed in gut, sediment and water, respectively. Diversity of microbial communities in respect of observed Operational Taxonomic Units, diversity indices (Shannon and Simpson), richness index (Chao1) were significantly high P(<0.05) in 60 DoC in gut and 30 DoC in sediment. Beta diversity indicated separate clusters for bacterial communities in gut, sediment and water samples and formation of distinct community profiles. Core microbiome in P. vannamei rearing ponds over a time consisted of 9, 21 and 20 OTUs in gut, rearing water and sediment, respectively. This study helps to intervene with suitable beneficial microbes to establish aquaculture system thereby contributes to enhance the productivity, improve water quality and pond bottom condition and control the pathogenic agents at each stage of the culture
Paramphistomosis is the emerging fluke infection in young ruminants which results in high morbidity and mortality in tropics and sub-tropics. The present study was carried out to detect the sharing antigens among the purified somatic antigens of G. crumenifer and C. cotylophorum, in order to use as a candidate antigen for diagnosis of paramphistomosis in sheep. Immunoblot analysis of the purified somatic antigens of C. cotylophorum and G. crumenifer using their specific rabbit hyper immune serum revealed 3 common polypeptides at the range of 27, 29 and 60 kDa. Hence these three immunodominant peptides can be used candidate antigens in development of vaccines against ovine paraphistomosis and also for early diagnosis of infection.
The focus of the present study was to detect canine distemper virus in clinically suspected dogs and its molecular characterization. The detection of CDV N gene was carried out using RT-PCR and Nested PCR. The N gene positive cDNA were used for the amplification of partial H and F genes. H gene positive products were subjected to restriction digestion with NdeI. Phylogenetic tree of partial CDV H and F gene nucleotide sequences were constructed using maximum likelihood method.Attempts were made to isolate CDV in vero cells expressing SLAM and MDCK cell lines. Out of the 90 samples collected from CDV suspected dogs, 19 samples (21%) were found positive by RT-PCR and 21 samples (23%) by nested PCR. When the N gene positive cDNA were subjected to PCR amplification of partial H and F gene sequences, 1 positive amplification each was obtained for H and F genes using the published primers and 2 H and F gene positive amplifications were obtained using the primer designed in this study. Restriction digestion of the partial H gene products yielded 2 fragments, proving the CD viruses to be wild-type. Phylogenetic analysis of partial H and F gene nucleotide sequences revealed that the field CD viruses of this study were distinct and varied from the vaccine strain. None of the samples produced cytopathic effects evenafter3 passages in 2 different cell lines. However, the presence of virus in 1 sample in both the cell lines after second passage was confirmed by RT-PCR.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.