Identification and Typing of Canine Parvovirus Using Molecular Techniques

Aim: Canine parvovirus 2, the causative agent of acute hemorrhagic enteritis in dogs, is one of the most important pathogenic viruses. It causes a highly contagious and often fatal disease. The disease condition is complicated further due to emergence of a number of variants namely CPV-2a, CPV-2b, CPV-2c, new CPV 2a, new CPV 2b over the years and involvement of domestic and wild canines. The virus is shed in large numbers in the feces of infected dog and upto 7 to 10 days post-infection, therefore, the present study was designed to detect CPV and to identify the prevailing antigenic types of CPV using molecular techniques from rectal swabs of affected dogs. Methods: The rectal swabs were collected from dogs suspected of Canine Parvovirus and subjected to PCR, Nested PCR and Realtime PCR for identification and typing of CPV in infected dogs. Results: From the study it was found that the per cent positivity was high in dogs and was found to be 50% and 89% by PCR and nested polymerase reaction respectively when considered in suspected dogs. The most prevailing antigenic type as detected by Real time PCR was found to be CPV 2a. Conclusions: The study indicated the animals vaccinated for CPV were also found positive for the disease. This study helps to detect percent positivity of CPV in dogs and also is important to identify the prevailing antigenic types of CPV in the region.

Prevalence and molecular characterization of canine parvovirus

Background and Aim: Canine parvovirus (CPV) belonging to family Parvoviridae causes hemorrhagic gastroenteritis in dogs and heavy mortality in young dogs. The virus has three structural (VP1, VP2 and VP3) and two non-structural proteins (NS1 and NS2), VP2 being highly immunogenic. This study aims to study molecular epidemiology of CPV by sequence analysis of VP2 gene to determine the prevailing antigenic type(s) in the northern regions of India. Materials and Methods: A total of 118 rectal swabs collected from dogs exhibiting clinical signs of CPV infection were processed for the isolation of DNA and subjected to polymerase chain reaction (PCR) and nested PCR (NPCR). A total of 13 NPCR products selected randomly were subjected to sequence analysis of VP2 gene. Results: The percent positivity of CPV was found 28% and 70% by PCR and NPCR, respectively. Dogs with vaccination history against CPV too were found positive with a percent positivity of 24.10%. Gene sequencing and phylogenetic analysis of VP2 gene from these isolates revealed that most samples formed a clade with CPV-2a isolates. Conclusion: Sequence analysis and phylogenetic analysis of VP2 gene in the studied regions of northern India revealed that CPV-2a was the most prevalent antigenic type.

Detection of CPV 2a Antigen Type of Canine Parvovirus in the States of Punjab and Assam, India

Aim: Canine Parvovirus (CPV) is an emerging and re-emerging virus of canines. The study was undertaken to analyze VP2 gene of CPV in the isolates from dogs positive for CPV infection. Methods: The rectal swabs were collected from dogs suspected of CPV and subjected to PCR and nested PCR. The regions compared in the study were Punjab to represent north part of India and Assam to represent north-eastern part of India. The sequence analysis of VP2 gene of CPV was done using NCBI BLAST from the isolates which were positive for CPV by nested PCR. Further, phylogenetic analysis was done to understand the prevailing antigenic type of CPV from northern and north eastern part of India. Results: The sequence analysis revealed that all the sequences of VP2 gene from the samples had 98-99% homology with Canine Parvovirus and phylogenetic analysis revealed that CPV 2a antigenic type is circulating in both the regions selected in the study. Conclusions: The present study revealed that CPV 2a is circulating in the regions of Punjab and Assam part of India. Further sequence analysis of VP2 gene from more number of field isolates can throw better light on the prevailing antigenic type of CPV in various parts of India.

Characterization of Antigenic Relatedness between GII.4 and GII.17 Noroviruses by Use of Serum Samples from Norovirus-Infected Patients

ABSTRACTA novel GII.17 norovirus variant caused major gastroenteritis epidemics in China in 2014 to 2016. To explore the host immune factors in selection of the emergence of this new variant, we characterized its antigenic relatedness with the GII.4 noroviruses that have dominated in China for decades. Through an enzyme-linked immunosorbent assay (ELISA) and a histo-blood group antigen (HBGA) blocking assay using sera from GII.4 and the GII.17 variant-infected patients, respectively, we observed limited cross-immune reactivity by the ELISA but little reactivity by the HBGA blocking assay between GII.4 norovirus and the new GII.17 variant. Our data suggest that, among other possible factors, GII.4-specific herd immunity had little role in the emergence of the new GII.17 variant. Thus, GII.17 may be an important active antigenic type or immunotype that needs to be considered for future vaccine strategies against human noroviruses.

Дослідження протигерпетичної активності похідних амінопропанолу-2.

Introduction. Chemotherapy and chemoprophylaxis are some of the main and often the only possible ways to effective control of viral infections. Therefore, the study of antiviral properties of new substances with the known chemical structure is one of the main ways to create new antiviral agents.The aim of the study – to research the antiherpes activity of new aminopropanol-2 derivatives against the herpes simplex virus (HSV) antigenic type 1, strain VC.Research Methods. Antiherpes activity was determined in 8 aminopropanol-2 derivatives: norbornyl containing substance (compound No. 51), substance with cyclic substituents in alkoxi group (compound No. 48), substances with alicyclic substituents in alkoxi group (compounds No. 46, 47, 49, 50, 52 and 53). Evaluation of antiherpes activity of the studied compounds was performed in vitro on cell culture VNK (growing culture of hamster kidney). Ability to reduce of virus infectious titer and chemotherapeutic index (HTI) of the studied compounds was determined.Results and Discussion. It is established that the compound No. 53 inhibits HSV-I reproduction in 2 lg ID50 at a concentration of 1.56 µg/ml. HTI of compound No. 53 is equal to 64, which describes it as an effective inhibitor of HSV-I reproduction. Some antiherpes action in compounds No. 46, 47 and 51 was identified also, their HTI were 8, 4 and 4 respectively. Substances No. 48, 49, 50 and 52 do not show the antiherpes action.Conclusions. Among all tested aminopropanol-2 derivatives the compound No. 53 with clear antiherpes properties was determined. Compound No. 53 belongs to the substances with alicyclic substituents in alkoxi group and has such chemical formula: 1-(2-methyl-3-butinox)-3-(2.2.6.6-tetramethyl piperidine)-2-propanol hydrochloride. Compound No. 53 as alicyclic substituent in alkoxy group contains 2-methyl-3-butene, and amine moiety of this substance contains the radical 2.2.6.6 – tetramethylpiperidine. The obtained results will be useful in establishing the natural relationships "structure-activity", also it can be used to create active compounds with certain characteristics.

Scrub Typhus in Nepal

Unfortunately, it is not feasible to prepare an effective vaccine against scrub typhus, because of the extreme antigenic variation seen amongst the strains of O tsutsugamushi. Immunity acquired naturally against one antigenic type may not be protective against another type which might be currently circulating in the locality. This complexity continues and the problem of making an effective vaccine against this disease still persists.

An outbreak of a possibly new Salmonella enterica subspecies enterica serovar with the antigenic formula 11:z41:e,n,z15, Greece, March to May 2016: preliminary results

Eleven Salmonella spp. isolates with the antigenic type 11:z41:e,n,z15 - not referred to in the 9th edition of the White-Kauffman–Le Minor Scheme - were identified at the National Reference Laboratory for Salmonella in Greece. Their pulsed-field gel electrophoresis profiles were indistinguishable. No apparent epidemiological link has yet been identified; the results of a case–case study are pending.

The generation of influenza outbreaks by a network of host immune responses against a limited set of antigenic types

It is commonly believed that influenza epidemics arise through the incremental accumulation of viral mutations, culminating in a novel antigenic type that is able to escape host immunity. Successive epidemic strains therefore become increasingly antigenically distant from a founding strain. Here, we present an alternative explanation where, because of functional constraints on the defining epitopes, the virus population is characterized by a limited set of antigenic types, all of which may be continuously generated by mutation from preexisting strains and other processes. Under these circumstances, influenza outbreaks arise as a consequence of host immune selection in a manner that is independent of the mode and tempo of viral mutation. By contrast with existing paradigms, antigenic distance between epidemic strains does not necessarily accumulate with time in our model, and it is the changing profile of host population immunity that creates the conditions for the emergence of the next influenza strain rather than the mutational capabilities of the virus.

Characterization of enterotoxigenic Escherichia coli from diarrhoeal patients in Bangladesh using phenotyping and genetic profiling

A total of 99 isolates out of 370 colonization factor (CF)-positive, well-characterized enterotoxigenic Escherichia coli (ETEC) strains belonging to 13 different CF types isolated from diarrhoeal patients admitted to the hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh, were tested. The isolates were selected at random based on expression of the major CFs prevailing in Dhaka, Bangladesh, from 1996 to 1998. These isolates were characterized by O-antigenic serotyping, randomly amplified polymorphic DNA (RAPD) analysis and biochemical fingerprinting using the PhenePlate (PhP) system. The 99 ETEC isolates belonged to 10 O serogroups, the predominant ones being O6 (n=28), O115 (n=20) and O128 (n=20). Most isolates of serogroup O6 (CS1+CS3, 11/14; CS2+CS3, 5/8) belonged to the same PhP/RAPD type (H/f), whereas other isolates of serogroup O6 (n=12) belonged to different PhP/RAPD types (Si/f and F/c). Eleven serogroup O128 (CFA/I) isolates belonged to the same PhP/RAPD type (E/b), whereas the other O128 isolates formed different PhP/RAPD types. Fifteen (75 %) serogroup O115 isolates (together with fourteen isolates from serogroups O25, O114, O142 and O159) demonstrated two closely related common groups by PhP typing (A and A1) and belonged to the same PhP/RAPD type (A/a). Three major clonal groups were identified among the ETEC strains in this study, largely based on O-antigenic type, CF expression pattern and toxin profile.