Novel molecular approaches to combat vectors and vector-borne viruses: Special focus on RNA interference (RNAi) mechanisms.

Vector-borne diseases, such as dengue, chikungunya, zika, yellow fever etc pose significant burden among the infectious diseases globally, especially in tropical and sub-tropical regions. Globalization, deforestation, urbanization, climate change, uncontrolled population growth, inadequate waste management and poor vector-management infrastructure have all contributed to the expansion of vector habitats and subsequent increase in vector-borne diseases throughout the world. Conventional vector control methods, such as use of insecticides, have significant negative environmental repercussions in addition to developing resistance in vectors. Till date, a very few vaccines or antiviral therapies have been approved for the treatment of vector borne diseases. In this review, we have discussed emerging molecular approaches like CRISPR (clustered regularly interspaced short palindromic repeats)/Cas-9, sterile insect technique (SIT), release of insects carrying a dominant lethal (RIDL), Wolbachia (virus transmission blocking) and RNA interference (RNAi) to combat vector and vector-borne viruses. Due to the extensive advancements in RNAi research, a special focus has been given on its types, biogenesis, mechanism of action, delivery and experimental studies evaluating their application as anti-mosquito and anti-viral agent. These technologies appear to be highly promising in terms of contributing to vector control and antiviral drug development, and hence can be used to reduce global vector and vector-borne disease burden.

APOBEC3, TRIM5α, and BST2 polymorphisms in healthy individuals of various populations with special references to its impact on HIV transmission.

AIDS restriction genes (ARGs) like APOBEC3, TRIM5α, and BST2 can act as immunological detectors of the innate protective mechanism of the body. ARGs influence the course of viral pathogenesis and progression of the disease. The infection caused by different viruses including HIV activates the innate immune receptors leading to production of proinflammatory cytokines, interferons and signals that recruit and activate cells involved in the process of inflammation following induction of adaptive immunity. Differential expression of genes involved in viral infection decide the fate and subsequent susceptibility to infection and its clinical outcome. Nevertheless, comprehensive reports on the incidence of genetic polymorphism of APOBEC3s, TRIM5α, and BST-2 in the general population and its association with pathological conditions have not been described well. Therefore, the occurrence of APOBEC3, TRIM5α, and BST2 polymorphism in healthy individuals and its impact on HIV transmission was analyzed. We conducted an extensive search using the several databases including, EMBASE, PubMed (Medline), and Google Scholar. APOBEC3-D, -F, -G, and -H out of the seven human APOBEC3s, help in the control of viral infection. Amongst various restriction factors, TRIM5α and BST-2 also restrict the viral infection followed by the development of the disease. In the current review, a brief account of the polymorphism in the APOBEC3G, TRIM5α, and BST2 genes are explored among different populations along with the interaction of APOBEC3G with Vif protein. Furthermore, this review specifically focus on ARGs polymorphism (APOBEC3G, TRIM5α, and BST2) associated with HIV transmission.

In silico analysis and molecular characterization of Influenza A (H1N1) pdm09 virus circulating and causing major outbreaks in central India, 2009-2019.

BACKGROUND AND OBJECTIVES: Influenza A/H1N1pdm09 causes respiratory illness and remains a concern for public health. Since its first emergence in 2009, the virus has been continuously circulating in the form of its genetic variants. Influenza A/H1N1pdm09 surveillance is essential for uncovering emerging variants of epidemiologic and vaccine efficacy. The present study attempts in silico analysis and molecular characterization of Influenza A (H1N1) pdm09 virus circulating and causing major outbreaks in central India during 2009-2019. MATERIALS AND METHODS: We have investigated the antigenic drift analysis of 96 isolates' hemagglutinin (HA) gene sequences (59 central Indian and 37 local Indian and 28 global reference HA gene sequences) of Influenza A/H1N1pdm09 viruses from 2009 to 2019. The study includes mutational (Multiple sequence Alignment), phylogenetic (Maximum Likelihood Method), and statistical analysis (Covariance and correlation) of HA sequences submitted in NCBI, IRD and GISAID from central India. RESULTS: Phylogenetic analysis indicated maximum clustering of central Indian HA gene sequences in genogroup 6B. Analysis of amino acid sequence alignment revealed changes in receptor binding site (RBS). The frequency of S220T amino acid substitution was found to be high followed by S202T, K300E A273T, K180Q. The Karl Pearson correlation coefficient (r) and covariance between the number of mutations and the death toll was found +0.246 and +100.3 respectively. CONCLUSION: The study identifies the continuous genetic variations in the HA gene sequences of circulating Influenza A/H1N1pdm09 in central India from the year 2009 to 2019. Further suggesting importance of monitoring the gradual evolution of the virus with regards to an increase in virulence, pathogenicity and vaccine efficacy timely.

Identification and characterization of nonpolio enterovirus associated with nonpolio-acute flaccid paralysis in polio endemic state of Uttar Pradesh, Northern India.

Despite polio eradication, nonpolio enterovirus (NPEV) detection amid polio surveillance, which is considered to have implications in paralysis, requires attention. The attributes of NPEV infections in nonpolio-AFP (NPAFP) cases from Uttar Pradesh (UP), India, remain undetermined and are thus investigated. A total of 1839 stool samples collected from patients with acute flaccid paralysis (AFP) from UP, India, between January 2010 and October 2011 were analyzed as per the WHO algorithm. A total of 359 NPAFP cases yielded NPEVs, which were subjected to microneutralization assay, partial VP1 gene-based molecular serotyping and phylogenetic analysis. Demographic and clinical-epidemiological features were also ascertained. Echoviruses (29%) and Coxsackievirus (CV)-B (17%) were the most common viruses identified by the microneutralization assay. The molecular genotyping characterized the NPEVs into 34 different serotypes, corresponding to Enterovirus (EV)-A (1.6%), EV-B (94%) and EV-C (5.3%) species. The rarely described EV serotypes, such as EV-C95, CV-A20, EV-C105, EV-B75, EV-B101, and EV-B107, were also identified. NPEV-associated AFP was more prevalent in younger male children, peaked in the monsoon months and was predominantly found in the central part of the state. The NPEV strains isolated in the study exhibited genetic diversity from those isolated in other countries. These form part of a different cluster or subcluster existing in cocirculation, limited to India only. This study augments the understanding of epidemiological features and demonstrates the extensive diversity exhibited by the NPEV strains in NPAFP cases from the polio-endemic region. It also underscores the need or effective long-term strategies to monitor NPEV circulation and its associated health risks in the post-polio eradication era.

Genetic diversity of cosaviruses in nonpolio acute flaccid paralysis cases of undefined etiology, Northern India, 2010-2011.

BACKGROUND: No cases of wild poliovirus have been reported for more than one and a half years from India. Cases of acute flaccid paralysis (AFP) of undefined etiology continue to occur in the region. Despite the recent discovery of the human Cosavirus (HCoSV) in the feces of children from developing countries, there have been no studies of cosavirus infection in India. OBJECTIVES: To detect and characterize HCoSVs in stool specimens of nonpolio AFP cases by RT-PCR followed by sequencing. STUDY DESIGN: A total of 387 fecal samples collected from AFP cases in Uttar Pradesh, India, between May 2010 and April 2011, tested negative on cell culture according to WHO algorithm, were subjected to 5'-UTR region specific RT-PCR followed by sequencing to detect HCoSV. Molecular characterization of HCoSV strains was done by sequencing followed by phylogenetic analysis. RESULT: 123 (32%) samples tested positive for cosaviruses and 87 (70.7%) were identified for genetic variants by sequencing a 316-nucleotide interval in the partial 5'-UTR region. Cosavirus strains were characterized as putative species HCoSV-A (n=70; 82%), HCoSV-B (n=7; 8%), HCoSV-C (n=1; 1.1) and HCoSV-D (n=4; 4.5%) while 5 (5%) strains remain uncharacterized. The cosavirus infection appeared highest (63.5%) in younger children, and showed a distinct seasonality, with a late summer peak and winter low. CONCLUSION: This study demonstrates a diversity of cosavirus strains in circulation, and reports the first investigation of HCoSV infection in children with nonpolio acute flaccid paralysis in India. Currently, this study provides baseline data for further studies of HCoSV infections in children with common enteric infections in India.

Genetic variants of echovirus 13, northern India, 2010.

Nonpolio acute flaccid paralysis is increasing in India. To determine viral causes, we conducted cell culture and molecular analysis identification of nonpolio human enteroviruses associated with acute flaccid paralysis during March-August 2010 in northern India. The predominant nonpolio enterovirus found was echovirus 13, a serotype rarely isolated in India.

Identification of different lineages of measles virus strains circulating in Uttar Pradesh, North India.

BACKGROUND: Genetic analysis of measles viruses associated with recent cases and outbreaks has proven to bridge information gaps in routine outbreak investigations and has made a substantial contribution to measles control efforts by helping to identify the transmission pathways of the virus. MATERIALS AND METHODS: The present study describes the genetic characterization of wild type measles viruses from Uttar Pradesh, India isolated between January 2008 and January 2011. In the study, 526 suspected measles cases from 15 outbreaks were investigated. Blood samples were collected from suspected measles outbreaks and tested for the presence of measles specific IgM; throat swab and urine samples were collected for virus isolation and RT-PCR. Genotyping of circulating measles viruses in Uttar Pradesh was performed by sequencing a 450-bp region encompassing the nucleoprotein hypervariable region and phylogenetic analysis. RESULTS AND CONCLUSION: Based on serological results, all the outbreaks were confirmed as measles. Thirty eight strains were obtained. Genetic analysis of circulating measles strains (n = 38) in Uttar Pradesh from 235 cases of laboratory-confirmed cases from 526 suspected measles cases between 2008 and 2011 showed that all viruses responsible for outbreaks were within clade D and all were genotype D8.Analysis of this region showed that it is highly divergent (up to 3.4% divergence in the nucleotide sequence and 4.1% divergence in the amino acid sequence between most distant strains). Considerable genetic heterogeneity was observed in the MV genotype D8 viruses in North India and underscores the need for continued surveillance and in particular increases in vaccination levels to decrease morbidity and mortality attributable to measles.

Epidemiology and genetic relatedness of measles virus infection in Uttar Pradesh, India, during 2009-2010.

Measles surveillance and epidemiological investigation are beneficial tools for genetic analysis and documentation of the interruption of transmission of endemic measles. In this study, areas of Uttar Pradesh, India, associated with measles outbreaks were investigated. Random blood and urine samples were collected from clinically defined cases. The cases were investigated through extensive house-to house surveys. The cases were diagnosed clinically and serologically, and through genotyping of the virus. All of the cases were found to be serologically positive for measles. In the studied population, a 1.9% case fatality rate and an overall 16% attack rate of measles virus were found. Out of 10 outbreak areas, the measles virus D8 genotype was found in nine, and the D8 and A genotypes were found in the remaining area. This study calls for an improved surveillance system and intensive characterization of genotypes in circulation for the measles elimination program in India.