Detection of Nipah virus in Pteropus medius in 2019 outbreak from Ernakulam district, Kerala, India.

BACKGROUND: In June 2019, Nipah virus (NiV) infection was detected in a 21-year-old male (index case) of Ernakulum, Kerala, India. This study was undertaken to determine if NiV was in circulation in Pteropus species (spp) in those areas where the index case had visit history in 1 month. METHODS: Specialized techniques were used to trap the Pteropus medius bats (random sampling) in the vicinity of the index case area. Throat and rectal swabs samples of 141 bats along with visceral organs of 92 bats were collected to detect the presence of NiV by real-time reverse transcriptase-polymerase chain reaction (qRTPCR). Serum samples of 52 bats were tested for anti-NiV Immunoglobulin (Ig) G antibodies by Enzyme-Linked Immunosorbent Assay (ELISA). The complete genome of NiV was sequenced by next-generation sequencing (NGS) from the tissues and swab samples of bats. RESULTS: One rectal swab sample and three bats visceral organs were found positive for the NiV. Interestingly, 20.68% (12/58) of Pteropus were positive for anti-NiV IgG antibodies. NiV sequences of 18,172; 17,200 and 15,100 nucleotide bps could be retrieved from three Pteropus bats. CONCLUSION: A distinct cluster of NiV sequences, with significant net-evolutionary nucleotide divergence, was obtained, suggesting the circulation of new genotype (I-India) in South India. NiV Positivity in Pteropus spp. of bats revealed that NiV is circulating in many districts of Kerala state, and active surveillance of NiV should be immediately set up to know the hotspot area for NiV infection.

Characterization of Novel Reoviruses Wad Medani Virus (Orbivirus) and Kundal Virus (Coltivirus) Collected from Hyalomma anatolicum Ticks in India during Surveillance for Crimean Congo Hemorrhagic Fever.

In 2011, ticks were collected from livestock following an outbreak of Crimean Congo hemorrhagic fever (CCHF) in Gujarat state, India. CCHF-negative Hyalomma anatolicum tick pools were passaged for virus isolation, and two virus isolates were obtained, designated Karyana virus (KARYV) and Kundal virus (KUNDV), respectively. Traditional reverse transcription-PCR (RT-PCR) identification of known viruses was unsuccessful, but a next-generation sequencing (NGS) approach identified KARYV and KUNDV as viruses in the Reoviridae family, Orbivirus and Coltivirus genera, respectively. Viral genomes were de novo assembled, yielding 10 complete segments of KARYV and 12 nearly complete segments of KUNDV. The VP1 gene of KARYV shared a most recent common ancestor with Wad Medani virus (WMV), strain Ar495, and based on nucleotide identity we demonstrate that it is a novel WMV strain. The VP1 segment of KUNDV shares a common ancestor with Colorado tick fever virus, Eyach virus, Tai Forest reovirus, and Tarumizu tick virus from the Coltivirus genus. Based on VP1, VP6, VP7, and VP12 nucleotide and amino acid identities, KUNDV is proposed to be a new species of Coltivirus Electron microscopy supported the classification of KARYV and KUNDV as reoviruses and identified replication morphology consistent with other orbi- and coltiviruses. The identification of novel tick-borne viruses carried by the CCHF vector is an important step in the characterization of their potential role in human and animal pathogenesis.IMPORTANCE Ticks and mosquitoes, as well Culicoides, can transmit viruses in the Reoviridae family. With the help of next-generation sequencing (NGS), previously unreported reoviruses such as equine encephalosis virus, Wad Medani virus (WMV), Kammavanpettai virus (KVPTV), and, with this report, KARYV and KUNDV have been discovered and characterized in India. The isolation of KUNDV and KARYV from Hyalomma anatolicum, which is a known vector for zoonotic pathogens, such as Crimean Congo hemorrhagic fever virus, Babesia, Theileria, and Anaplasma species, identifies arboviruses with the potential to transmit to humans. Characterization of KUNDV and KARYV isolated from Hyalomma ticks is critical for the development of specific serological and molecular assays that can be used to determine the association of these viruses with disease in humans and livestock.

Full-genome sequences of the first two SARS-CoV-2 viruses from India.

Background & objectives: Since December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has globally affected 195 countries. In India, suspected cases were screened for SARS-CoV-2 as per the advisory of the Ministry of Health and Family Welfare. The objective of this study was to characterize SARS-CoV-2 sequences from three identified positive cases as on February 29, 2020. Methods: Throat swab/nasal swab specimens for a total of 881 suspected cases were screened by E gene and confirmed by RdRp (1), RdRp (2) and N gene real-time reverse transcription-polymerase chain reactions and next-generation sequencing. Phylogenetic analysis, molecular characterization and prediction of B- and T-cell epitopes for Indian SARS-CoV-2 sequences were undertaken. Results: Three cases with a travel history from Wuhan, China, were confirmed positive for SARS-CoV-2. Almost complete (29,851 nucleotides) genomes of case 1, case 3 and a fragmented genome for case 2 were obtained. The sequences of Indian SARS-CoV-2 though not identical showed high (~99.98%) identity with Wuhan seafood market pneumonia virus (accession number: NC 045512). Phylogenetic analysis showed that the Indian sequences belonged to different clusters. Predicted linear B-cell epitopes were found to be concentrated in the S1 domain of spike protein, and a conformational epitope was identified in the receptor-binding domain. The predicted T-cell epitopes showed broad human leucocyte antigen allele coverage of A and B supertypes predominant in the Indian population. Interpretation & conclusions: The two SARS-CoV-2 sequences obtained from India represent two different introductions into the country. The genetic heterogeneity is as noted globally. The identified B- and T-cell epitopes may be considered suitable for future experiments towards the design of vaccines and diagnostics. Continuous monitoring and analysis of the sequences of new cases from India and the other affected countries would be vital to understand the genetic evolution and rates of substitution of the SARS-CoV-2.

Experimental Zika virus infection in Aedes aegypti: Susceptibility, transmission & co-infection with dengue & chikungunya viruses.

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.

Zika virus Pathogenesis in Infant Mice after Natural Transmission by the Bite of Infected Mosquitoes.

OBJECTIVES: The objective of this study was to understand natural disease progression in infant CD1 mice after the bite of Aedes aegypti mosquitoes infected by the Zika virus (ZIKV, MR-766 strain). METHODS: A. aegypti mosquitoes were experimentally infected with ZIKV MR-766 strain via the oral feeding route. Infected mosquitoes were allowed to feed on infant CD1 mice. Sick mice were euthanized, and their organs were collected and subjected to real-time RT-PCR, histo-pathology, and immunohistochemistry. RESULTS: Clinical symptoms appeared in mice after 4-5 days of being bitten by mosquitoes, following which they were euthanized. Real-time RT-PCR analysis showed the presence of viral RNA in various organs such as the brain, liver, kidney, spleen, lungs, and intestines of the mice. The brain tissue specimens showed higher viral loads as determined by threshold values (Ct value) in the real-time RT-PCR assay. Histopathological and immunohistochemistry studies also revealed the presence of the virus and associated lesions in the brain, indicating that ZIKV shows tropism for neuronal tissue. CONCLUSIONS: This study demonstrates ZIKV pathogenesis in infant CD1 mice and that these mice are highly susceptible to natural infection with this ZIKV strain.

Cross-sectional Serosurvey of Crimean-Congo Hemorrhagic Fever Virus IgG in Livestock, India, 2013-2014.

We conducted a cross-sectional serosurvey of Crimean-Congo hemorrhagic fever (CCHF) among livestock in 22 states and 1 union territory of India. A total of 5,636 samples from bovines, sheep, and goats were screened for CCHF virus IgG. IgG was detected in 354 samples, indicating that this virus is widespread in this country.

Characterization of a strain of quaranfil virus isolated from soft ticks in India. Is quaranfil virus an unrecognized cause of disease in human and animals?"

The soft ticks collected during a field survey in Karnataka state, India, in 1983, yielded a novel virus isolate, which caused mortality in an infant mouse upon inoculation. Attempts at characterizing the virus using the conventional methods were unsuccessful, which prompted us to study it by Next-Generation Sequencing (NGS). This virus isolate was obtained from the viral repository of National Institute of Virology, and an initial virus stock was prepared as a mouse brain homogenate. The virus stock showed cytopathic effects in different cell-lines and was used in NGS. Based on the complete genome sequence, obtained using de novo and reference mapping approach, the virus isolate was identified as a Quaranfil virus (QRFV) belonging to the family Orthomyxoviridae, genus Quaranjavirus. The genome size of the virus is 11,427 nucleotides which consist of 6 segments encoding six proteins. Homology analysis suggested this isolate as similar to QRFV of Afghanistan. In silico analysis showed the HA protein secondary structure to be a class III penetrance similar to Thogotovirus. QRFV was first isolated in 1953 from ticks [Cairo, Egypt] and subsequently reported from other geographical areas. This is the first report describing the presence of QRFV from India. This discovery emphasizes the need for investigating mild febrile illness cases with influenza-like symptoms, particularly in the area of high risk for tick bites.

Molecular diversity of Coxsackievirus A10 circulating in the southern and northern region of India [2009-17].

Non-Polio EnteroViruses (NPEV) are one of the known causative agents of Acute Flaccid Paralysis (AFP). In the present study, we identified, sequenced and characterized the complete genome of sixty-five Coxsackievirus-A10, an NPEV. These were isolated from stool specimens of AFP cases from Bihar, Karnataka, Kerala, and Uttar Pradesh (UP) states of India. Evolutionary analysis of complete genome (7420 nucleotides) and VP1 gene (894 nucleotides) demonstrates that there are four different intra-typic strains circulating in India which were dissimilar to Chinese strains. First intratypic strain circulating in UP, Bihar, and Karnataka; second in UP and Karnataka; third in UP and Bihar and; fourth was restricted only to Kerala state. The divergence of Kerala strain with respect to all other circulating strain of UP, Bihar and Karnataka states in India is 24%, 24.9%, and 24.4% respectively. Recombinations were observed between few of these strains which might be one of the factors of the observed intra-typic diversity. ARTICLE SUMMARY LINE: We report the identification, characterization and phylogenetic analysis of sixty-five Non-Polio Enterovirus (NPEV) isolates, performed during the year 2009-17, causing acute flaccid paralysis in pediatric cases with their divergences and recombinations from four states of India.

Serosurvey of Crimean-Congo hemorrhagic fever virus in domestic animals, Gujarat, India, 2013.

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne viral disease that causes a fatal hemorrhagic illness in humans. This disease is asymptomatic in animals. CCHF was first confirmed in a nosocomial outbreak in 2011 in Gujarat State. Another notifiable outbreak occurred in July, 2013, in Karyana Village, Amreli district, Gujarat State. Anti-CCHF virus (CCHFV) immunoglobulin G (IgG) antibodies were detected in domestic animals from the adjoining villages of the affected area, indicating a considerable amount of positivity against domestic animals. The present serosurvey was carried out to determine the prevalence of CCHFV among bovine, sheep, and goat populations from 15 districts of Gujarat State, India. A total of 1226 serum samples from domestic animals were screened for IgG antibodies using a CCHF animal IgG enzyme-linked immunosorbent assay (ELISA) kit from the Centers for Disease Control and Prevention. Antibodies were detected in all the 15 districts surveyed; with positivity of 12.09%, 41.21%, and 33.62% in bovine, sheep, and goat respectively. This necessitates the surveillance of CCHFV IgG antibodies in animals and hemorrhagic fever cases in human.