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Background & objectives: Kyasanur forest disease (KFD) is a zoonotic tick-borne disease across the Western Ghats of India. With the discovery of a cluster of human KFD cases in the Wayanad district of Kerala, the present study was focused on detecting KFD virus (KFDV) in tick populations. To manage this disease, it is necessary to understand the diversity of the tick species and factors influencing the distribution, abundance and prevalence of infected ticks in Wayanad district. Methods: Surveys were conducted from November 2016 to May 2018 in four forest ranges of Wayanad district. Ticks were collected by the dragging method and were identified to species level and assayed for virus detection using real-time polymerase chain reaction. Results: A total of 25,169 ticks were collected from 64 sites. Of the identified species, Haemaphysalis spinigera was the most abundant (56.64%), followed by H. turturis 9047 (35.94%), H. bispinosa 999 (3.96%), Amblyomma integrum 691 (2.74%), H. kyasanurensis (0.55%), Rhipicephalus sanguineus (0.08%), Hyalomma marginatum (0.02%), H. cuspidata (0.01%), R.microplus (0.01%) and Dermacentor auratus (0.003%). The nymphal stage was predominant from December to February having peak activity in January. A total of 572 pools were screened for the presence of KFDV, of which 21 pools were positive. The infection rates in H. spinigera and H. turturis tick were 2.62 and 1.04 per cent, respectively. Interpretation & conclusions: The circulation of KFDV was detected and its correlation with the prevalence in ticks near the fragmented forest and teak plantation areas of Wayanad district. Residents and visitors of these regions may become vulnerable to tick bites and to an increased risk of KFD as the distribution of established, infected tick populations continues to expand. [ABSTRACT FROM AUTHOR]

Background & objectives: The presence of Cat Que virus (CQV) in Culex mosquitoes and pigs has been reported in China and Vietnam. Due to the spread of similar species of the Culex mosquitoes in India, there is a need to understand the replication kinetics of this virus in mosquito models. As a part of preparedness and to identify the presence of this CQV in humans and swine, this study was carried out to develop diagnostic tests. Methods: Serological and molecular diagnostic assays were developed for testing the mosquito population, human and swine serum samples. In this line, RNA-dependent RNA polymerase (L), glycoprotein (M) and nucleocapsid (S) genes-based reverse transcription-polymerase chain reaction (RT-PCR) assays were developed for CQV. Real-time RT-PCR was used for screening of retrospectively collected human serum samples (n=1020) with acute febrile illness during 2014-2017. Simultaneously, an in-house anti-CQV swine and human IgG ELISAs were also developed to detect anti-CQV IgG antibody. Human serum samples (n=883) with post-onset of disease (POD) >4 days and swine serum samples (n=459) were tested for the presence of anti-CQV IgG antibodies. CQV NIV 612,045 isolate was used for susceptibility and replication kinetics experiment using three different species of mosquitoes to understand its behaviour in Indian mosquitoes. Results: All human serum samples (n=1020) screened for the presence of CQV using real-time RTPCR were found to be negative. Anti-CQV IgG antibody positivity was recorded in two of 883 human serum samples tested. Virus susceptibility experiments indicated that three species of mosquito, namely Aedes aegypti, Culex quinquefasciatus and Cx. tritaeniorhynchus supported multiplication of CQV by intrathoracic as well as artificial membrane/oral feeding routes. Interpretation & conclusions: Anti-CQV IgG antibody positivity in human serum samples tested and the replication capability of CQV in mosquitoes indicated a possible disease causing potential of CQV in Indian scenario. Screening of more human and swine serum samples using these assays is required as a proactive measure for understanding the prevalence of this neglected tropical virus. [ABSTRACT FROM AUTHOR]

Infectious diseases remain as the major causes of human and animal morbidity and mortality leading to significant healthcare expenditure in India. The country has experienced the outbreaks and epidemics of many infectious diseases. However, enormous successes have been obtained against the control of major epidemic diseases, such as malaria, plague, leprosy and cholera, in the past. The country's vast terrains of extreme geo-climatic differences and uneven population distribution present unique patterns of distribution of viral diseases. Dynamic interplays of biological, socio-cultural and ecological factors, together with novel aspects of human-animal interphase, pose additional challenges with respect to the emergence of infectious diseases. The important challenges faced in the control and prevention of emerging and re-emerging infectious diseases range from understanding the impact of factors that are necessary for the emergence, to development of strengthened surveillance systems that can mitigate human suffering and death. In this article, the major emerging and re-emerging viral infections of public health importance have been reviewed that have already been included in the Integrated Disease Surveillance Programme. [ABSTRACT FROM AUTHOR]

With increasing awareness regarding biorisk management worldwide, many biosafety laboratories are being setup in India. It is important for the facility users, project managers and the executing agencies to understand the process of validation and certification of such biosafety laboratories. There are some international guidelines available, but there are no national guidelines or reference standards available in India on certification and validation of biosafety laboratories. There is no accredited government/private agency available in India to undertake validation and certification of biosafety laboratories. Therefore, the reliance is mostly on indigenous experience, talent and expertise available, which is in short supply. This article elucidates the process of certification and validation of biosafety laboratories in a concise manner for the understanding of the concerned users and suggests the important parameters and criteria that should be considered and addressed during the laboratory certification and validation process. [ABSTRACT FROM AUTHOR]

Newly emerging and re-emerging viral infections are of major public health concern. Bunyaviridae family of viruses comprises a large group of animal viruses. Clinical symptoms exhibited by persons infected by viruses belonging to this family vary from mild-to-severe diseases i.e., febrile illness, encephalitis, haemorrhagic fever and acute respiratory illness. Several arthropods-borne viruses have been discovered and classified at serological level in India in the past. Some of these are highly pathogenic as the recent emergence and spread of Crimean-Congo haemorrhagic fever virus and presence of antibodies against Hantavirus in humans in India have provided evidences that it may become one of the emerging diseases in this country. For many of the discovered viruses, we still need to study their relevance to human and animal health. Chittoor virus, a variant of Batai virus; Ganjam virus, an Asian variant of Nairobi sheep disease virus; tick-borne viruses such as Bhanja, Palma and mosquito-borne viruses such as Sathuperi, Thimiri, Umbre and Ingwavuma viruses have been identified as the members of this family. As Bunyaviruses are three segmented RNA viruses, they can reassort the segments into genetically distinct viruses in target cells. This ability is believed to play a major role in evolution, pathogenesis and epidemiology of the viruses. Here, we provide a comprehensive overview of discovery, emergence and distribution of Bunyaviruses in India. [ABSTRACT FROM AUTHOR]

Since the enactment of environmental protection Act in 1989 and Department of Biotechnology (DBT) guidelines to deal with genetically modified organisms, India has embarked on establishing various levels of biosafety laboratories to deal with highly infectious and pathogenic organisms. Occurrence of outbreaks due to rapidly spreading respiratory and haemorrhagic fever causing viruses has caused an urgency to create a safe laboratory environment. This has thus become a mandate, not only to protect laboratory workers, but also to protect the environment and community. In India, technology and science are progressing rapidly. Several BSL-3 [=high containment] laboratories are in the planning or execution phase, to tackle biosafety issues involved in handling highly infectious disease agents required for basic research and diagnosis. In most of the developing countries, the awareness about biocontainment has increased but planning, designing, constructing and operating BSL-3 laboratories need regular updates about the design and construction of facilities and clear definition of risk groups and their handling which should be in harmony with the latest international practices. This article describes the major steps involved in the process of construction of a BSL-3 laboratory in Indian settings, from freezing the concept of proposal to operationalization phase. The key to success of this kind of project is strong institutional commitment to biosafety norms, adequate fund availability, careful planning and designing, hiring good construction agency, monitoring by experienced consultancy agency and involvement of scientific and engineering personnel with biocontainment experience in the process. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented about the first confirmed case of Crimean-Congo haemorrhagic fever from Sirohi district in Rajasthan State, India.

The WHO emergency use-listed (EUL) COVID-19 vaccines were developed against early strains of SARS-CoV-2. With the emergence of SARS-CoV-2 variants of concern (VOCs) - Alpha, Beta, Gamma, Delta and Omicron, it is necessary to assess the neutralizing activity of these vaccines against the VOCs. PubMed and preprint platforms were searched for literature on neutralizing activity of serum from WHO EUL vaccine recipients, against the VOCs, using appropriate search terms till November 30, 2021. Our search yielded 91 studies meeting the inclusion criteria. The analysis revealed a drop of 0-8.9-fold against Alpha variant, 0.3-42.4-fold against Beta variant, 0-13.8-fold against Gamma variant and 1.35-20-fold against Delta variant in neutralization titres of serum from the WHO EUL COVID-19 vaccine recipients, as compared to early SARS-CoV-2 isolates. The wide range of variability was due to differences in the choice of virus strains selected for neutralization assays (pseudovirus or live virus), timing of serum sample collection after the final dose of vaccine (day 0 to 8 months) and sample size (ranging from 5 to 470 vaccinees). The reasons for this variation have been discussed and the possible way forward to have uniformity across neutralization assays in different laboratories have been described, which will generate reliable data. Though in vitro neutralization studies are a valuable tool to estimate the performance of vaccines against the backdrop of emerging variants, the results must be interpreted with caution and corroborated with field-effectiveness studies. [ABSTRACT FROM AUTHOR]

A letter to the editor about the Crimean-Congo hemorrhagic fever (CCHF) caused by Nairovirus is presented.

Background & objectives: Focus on non-polio enteroviruses (NPEVs) causing acute flaccid paralysis (AFP) due to myelitis has increased with the containment of the poliovirus. Enterovirus-B88 (EV-B88) has been associated with the AFP cases in Bangladesh, Ghana, South Africa, Thailand and India. In India, EV-B88 infection was linked to AFP a decade ago; however, to date, no complete genome has been made available. In this study, the complete genome sequence of EV-B88 was identified and reported from two different States (Bihar and Uttar Pradesh) in India using the next-generation sequencing technique. Methods: Virus isolation was performed on the three AFP suspected cases as per the WHO-recommended protocol. Samples showing cytopathic effects in the human Rhabdocarcinoma were labelled as NPEVs. Next-generation sequencing was performed on these NPEVs to identify the aetiological agent. The contiguous sequences (contigs) generated were identified, and reference-based mapping was performed. Results: EV-B88 sequences retrieved in our study were found to be 83 per cent similar to the EV-B88 isolate from Bangladesh in 2001 (strain: BAN01-10398; Accession number: AY843306.1). Recombination analyses of these samples demonstrate recombination events with sequences from echovirus-18 and echovirus-30. Interpretation & conclusions: Recombination events in the EV-B serotypes are known, and this work reconfirms the same for EV-B88 isolates also. This study is a step in increasing the awareness about EV-B88 in India and emphasizes future studies to be conducted in the identification of other types of EV present in India. [ABSTRACT FROM AUTHOR]

Background & objectives: Nipah virus (NiV) is a zoonotic paramyxovirus that causes fatal encephalitis in humans. Enzyme Linked Immunosorbent Assay (ELISA) is a safe, sensitive, specific, and affordable diagnostic tool that can be used during screening of large-scale epidemiological investigations. Development and evaluation of IgM and IgG ELISA for screening serum samples of NiV suspected cases would also help in planning public health interventions. Methods: An IgM capture (MAC) ELISA and an indirect IgG ELISA were developed using NiV antigen to detect IgM and IgG antibodies against NiV in human sera. The sensitivity, specificity, and crossreactivity of the assays were evaluated using NiV IgM, IgG positive, negative human sera and measles, mumps, rubella, Crimean-Congo haemorrhagic fever, Kyasanur forest disease IgM, IgG positive sera, respectively. Results: The developed anti-NiV IgM and IgG ELISAs have shown specificity of 99.28 per cent and sensitivity of 100 per cent compared to reference test from Centers for Disease Control and Prevention, USA. Assays demonstrated negative predictive value of 100 per cent and positive predictive value as 90 and 93.94 per cent for anti-Nipah IgM ELISA and IgG ELISA respectively with test accuracy of 99.33 per cent. Interpretation & conclusions: Timely diagnosis of NiV is crucial for the management of cases, which could prevent further spread of infection in the community. IgM ELISA can be used as primary diagnostic tool followed by polymerase chain reaction. These assays have advantages of its applicability during outbreak investigations and surveillance activities at hospital or onsite laboratories with basic biosafety practices. [ABSTRACT FROM AUTHOR]

Background & objectives: Pipistrellus ceylonicus bat species is widely distributed in South Asia, with additional populations recorded in China and Southeast Asia. Bats are the natural reservoir hosts for a number of emerging zoonotic diseases. Attempts to isolate bat-borne viruses in various terrestrial mammalian cell lines have sometimes been unsuccessful. The bat cell lines are useful in isolation and propagation of many of the viruses harboured by bats. New stable bat cell lines are needed to help such investigations and to assist in the study of bat immunology and virus-host interactions. In this study we made an attempt to develop a cell line from P ceylonicus bats. Methods: An effort was made to establish cell line from embryo of P ceylonicus species of bat after seeding to Dulbecco's modified eagle medium (DNLEM) supplemented with 10 per cent foetal bovine serum; a primary cell line was established and designated as NIV-BtEPC. Mitochondrial DNA profile analysis was done using cyt-b and ND-i gene sequences from the cell line. Phylogenetic tree was constructed using neighbour-joining algorithm for cyt-b.and ND-i genes with 1000-bootstrap replicates. Results: NIV-BtEPC cell line was susceptible to Chandipura (CHPV) and novel adenovirus (BtAdv- RLM) isolated from Rousettus leschenaulti from India but did not support multiplication of a number of Bunyaviruses, Alphaviruses and Flavivirus. This might be useful for isolation of a range of viruses and investigation of unknown aetiological agents. Interpretation & conclusions: In this study, a new bat cell line was developed from P ceylonicus. This cell line was successfully tested for the susceptibility to Chandipura and BtAdv-RLM virus isolated from bats. The approach developed and optimised in this study maybe applicable to the other species of bats and this established cell line can be used to facilitate virus isolation and basic research into virus-host interaction. [ABSTRACT FROM AUTHOR]

The article discusses the difference in vector ticks dropping rhythm that governs the epidemiology of Crimean-Congo haemorrhagic fever (CCHFV) and Kyasanur forest disease (KF) in India. The study involves ticks of the genus haemaphysalis for KFD virus and hyalomma for CCHFV. It mentions the several differences in the bionomics of the two vector tick species. Also noted are the required two hosts to complete their life cycles.

Background & objectives: Polio, measles, rubella, influenza and rotavirus surveillance programmes are of great public health importance globally. Virus isolation using cell culture is an integral part of such programmes. Possibility of unintended isolation of SARS-CoV-2 from clinical specimens processed in biosafety level-2 (BSL-2) laboratories during the above-mentioned surveillance programmes, cannot be ruled out. The present study was conducted to assess the susceptibility of different cell lines to SARS-CoV-2 used in these programmes. Methods: Replication of SARS-CoV-2 was studied in RD and L20B, Vero/hSLAM, MA-104 and Madin–Darby Canine Kidney (MDCK) cell lines, used for the isolation of polio, measles, rubella, rotavirus and influenza viruses, respectively. SARS-CoV-2 at 0.01 multiplicity of infection was inoculated and the viral growth was assessed by observation of cytopathic effects followed by real-time reverse transcription–polymerase chain reaction (qRT-PCR). Vero CCL-81 cell line was used as a positive control. Results: SARS-CoV-2 replicated in Vero/hSLAM, and MA-104 cells, whereas it did not replicate in L20B, RD and MDCK cells. Vero/hSLAM, and Vero CCL-81 showed rounding, degeneration and detachment of cells; MA-104 cells also showed syncytia formation. In qRT-PCR, Vero/hSLAM and MA-104 showed 106 and Vero CCL-81 showed 107 viral RNA copies per µl. The 50 per cent tissue culture infectious dose titres of Vero/hSLAM, MA-104 and Vero CCL-81 were 105.54, 105.29 and 106.45/ml, respectively. Interpretation & conclusions: Replication of SARS-CoV-2 in Vero/hSLAM and MA-104 underscores the possibility of its unintended isolation during surveillance procedures aiming to isolate measles, rubella and rotavirus. This could result in accidental exposure to high titres of SARS-CoV-2, which can result in laboratory acquired infections and community risk, highlighting the need for revisiting biosafety measures in public health laboratories. [ABSTRACT FROM AUTHOR]

Background & objectives: Varicella zoster virus (VZV) strains are classified into six different clades based on the sequencing of its genome. Clades 4 and 5 are reported from India based on the single-nucleotide polymorphism (SNP). Till now, multiple clade circulations using partial sequences have been reported from India due to the lack of availability of the full VZV genome sequence. This study conducted a genome sequencing of VZV in India to identify circulating clade. Methods: Four clinical samples obtained from symptomatic patients tested positive for VZV by real-time PCR were used. These four samples were preferred to retrieve the genomic VZV sequence using the nextgeneration sequencing method. A reference-based assembly method was used to retrieve the genome of VZV, which was further analyzed. Results: At the least, 98 per cent of the whole-genome sequences were recovered from the four samples. The VZV sequences obtained in this study formed a separate monophyletic branch with clade 5, indicating it to be evolved from a distinct ancestor. The nucleotide-based analysis revealed 13 different SNP mutations and one multiple nucleotide variation in the VZV sequences when compared to one of the clade 5 genomes having accession number: DQ457052.1. Interpretation & conclusions: The present study described approximately 98 per cent of the genome sequence of VZV from India. The availability of these genomic sequences will lead to enrichment in the clinical genomic data set from India. The available data would help in the development of diagnostic methods along with evolutionary analysis. We hypothesize the existence of a new sub-clade that belongs to clade 5 and propose further experiments to confirm these results. [ABSTRACT FROM AUTHOR]

Background & objectives: Since the beginning of the year 2020, the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) impacted humankind adversely in almost all spheres of life. The virus belongs to the genus Betacoronavirus of the family Coronaviridae. SARS-CoV-2 causes the disease known as coronavirus disease 2019 (COVID-19) with mild-to-severe respiratory illness. The currently available diagnostic tools for the diagnosis of COVID-19 are mainly based on molecular assays. Real-time reverse transcription-polymerase chain reaction is the only diagnostic method currently recommended by the World Health Organization for COVID-19. With the rapid spread of SARS-CoV-2, it is necessary to utilize other tests, which would determine the burden of the disease as well as the spread of the outbreak. Considering the need for the development of such a screening test, an attempt was made to develop and evaluate an IgG-based ELISA for COVID-19. Methods: A total of 513 blood samples (131 positive, 382 negative for SARS-CoV-2) were collected and tested by microneutralization test (MNT). Antigen stock of SARS-CoV-2 was prepared by propagating the virus in Vero CCL-81 cells. An IgG capture ELISA was developed for serological detection of anti- SARS-CoV-2 IgG in serum samples. The end point cut-off values were determined by using receiver operating characteristic (ROC) curve. Inter-assay variability was determined. Results: The developed ELISA was found to be 92.37 per cent sensitive, 97.9 per cent specific, robust and reproducible. The positive and negative predictive values were 94.44 and 98.14 per cent, respectively. Interpretation & conclusions: This indigenously developed IgG ELISA was found to be sensitive and specific for the detection of anti-SARS-CoV-2 IgG in human serum samples. This assay may be used for determining seroprevalence of SARS-CoV-2 in a population exposed to the virus [ABSTRACT FROM AUTHOR]

Background & objectives: There are reports about the susceptibility of Aedes mosquitoes to ZIKV from various countries, however, no such information is available from Indian sub-continent, although, high level of group cross-reactivity of ZIKV with other flaviviruses has been reported. During outbreak situations, many cases of Dengue (DEN) and Chikungunya (CHIK) are reported. In such scenario, vector mosquitoes are likely to get co-infection/secondary-infection with one or other virus. The present study was carried out to determine the susceptibility of Indian strain of Aedes aegypti to Zika virus (ZIKV) strain (MR-766) and the effect of co-infection/super-infection with either dengue virus (serotype-2) (DENV) or chikungunya virus (CHIKV) on ZIKV replication. Methods: Ae. aegypti mosquitoes used in this study were reared for many generations since 1980 at laboratory colony maintained at the ICMR-National Institute of Virology, Pune, India. Transmissibility of ZIKV from infected mosquitoes to suckling mice was also studied. Mosquitoes were experimentally infected with ZIKV and super-infected with either DENV or CHIKV via membrane-feeding route and incubated for 14 days at 28±2°C and humidity of 85±5 per cent. Replication of these viruses in mosquitoes was confirmed using real-time reverse transcription-polymerase chain reaction and immunofluorescence assay. Twenty infected mosquitoes were allowed to feed upon four suckling CD1 mice for about 30 min. Transmission of the ZIKV by infected mosquitoes to suckling mice was confirmed by the appearance of clinical signs and the presence of viral RNA in different organs. Results: Concomitant infection of mosquitoes with all the three viruses showed simultaneous propagation of all three viruses, confirmed by real time RT-PCR and IFA. Infection of mosquitoes with CHIKV followed by ZIKV showed positivity in individual head squashes (7%) for both viruses using IFA; only 8.3 per cent showed dual positivity with primary infection of ZIKV followed by DENV; 8.3 per cent dual infection positivity was observed when infected with DENV followed by ZIKV; 5 per cent showed dual infection was observed when infected with ZIKV followed by CHIKV. Ae. aegypti was found to be susceptible to ZIKV strain as ZIKV could be detected from the second post-infection day (PID) in infected mosquitoes. Transmission of ZIKV to mice by the bite of infected Ae. aegypti establishes this species as a potential vector. Interpretation & conclusions: From super-infection experiments, it was concluded that ZIKV might have a relative advantage in replication dynamics over DENV. Vertical transmission was not observed for ZIKV in experimentally infected mosquitoes (n=920 larvae). Further studies are required to understand the possibility of silently circulating ZIKV in India, which remain non-detected because of lack of surveillance. [ABSTRACT FROM AUTHOR]

Background & objectives: Differential diagnosis of Crimean-Congo haemorrhagic fever (CCHF) from other acute febrile illnesses with haemorrhagic manifestation is challenging in India. Nosocomial infection is a significant mode of transmission due to exposure of healthcare workers to blood and body fluids of infected patients. Being a risk group 4 virus, laboratory confirmation of infection is not widely available. In such a situation, early identification of potential CCHF patients would be useful in limiting the spread of the disease. The objective of this study was to retrospectively analyse clinical and laboratory findings of CCHF patients that might be useful in early detection of a CCHF case in limited resource settings. Methods: Retrospective analysis of clinical and laboratory data of patients suspected to have CCHF referred for diagnosis from Gujarat and Rajasthan States of India (2014-2015) was done. Samples were tested using CCHF-specific real time reverse transcription (RT)-PCR and IgM ELISA. Results: Among the 69 patients referred, 21 were laboratory confirmed CCHF cases of whom nine had a history of occupational exposure. No clustering of cases was noted. Platelet count cut-off for detection of positive cases by receiver operating characteristic curve was 21.5×10[9]/l with sensitivity 82.4 per cent and specificity 82.1 per cent. Melaena was a significant clinical presentation in confirmed positive CCHF patients. Interpretation & conclusions: The study findings suggest that in endemic areas thrombocytopenia and melaena may be early indicators of CCHF. Further studies are needed to confirm these findings. [ABSTRACT FROM AUTHOR]

The emergence of Zika virus (ZiV), a mosquito borne Flavivirus like dengue (DEN) and chikunguny (CHIK), in Brazil in 2014 and its spread to various countries have led to a global health emergency. Aedes aegypti is the major vector for ZiV. Fast dissemination of this virus in different geographical areas posses a major threat especially to regions where the population lacks herd immunity against the ZiV and there is abundance of Aedes mosquitoes. In this review, we focus on current global scenario, epidemiology, biology, diagnostic challenges and remedial measures for ZiV considering the Indian perspective. [ABSTRACT FROM AUTHOR]