Molecular characterization & recombination analysis of complete enterovirus-88 isolated from acute flaccid paralysis cases in India

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.

Urinary immunoglobulins in viral diagnosis: An overview

Antibody detection by serological methods gained a lot of interest in recent years and has become the backbone of virological diagnosis. Despite the detection of all five classes of immunoglobulins in urine, not much attention has been paid to the use of urine as a diagnostic sample to detect viral antibodies. Unlike venipuncture, this non-invasive mode of sample collection can help cover all age groups, especially paediatric and old age patients, where blood collection is difficult. Using urine as a sample is also economical and involves lesser risk in sample collection. The antibodies are found to be stable in urine at room temperature for a prolonged period, which makes the sample transport management easier as well. A few recent studies, have also shown that the detection limit of antibodies in urine is at par with serum or other clinical material. So, the ease in sample collection, availability of samples in large quantity and stability of immunoglobulins in urine for prolonged periods can make urine an ideal sample for viral diagnosis.

Experiences of Indian Council of Medical Research with tick-borne zoonotic infections: Kyasanur Forest disease & Crimean-Congo haemorrhagic fever in India with One Health focus

Emergence and re-emergence of several pathogens have been witnessed by this century in the form of outbreaks, epidemics and pandemics. In India, the influencing factor that promotes dissemination of emerging and re-emerging viral infections is the biogeographical zones: a megadiverse country, characterized by varied geographical, climatic conditions and ever-changing socio-economical and geopolitical issues. These influence the movement of humans and animals and add layers of complexity for the identification and timely management of infectious diseases. This review focuses on two tick-borne infections: Crimean-Congo haemorrhagic fever (CCHF) and Kyasanur forest disease (KFD). In the last two decades, these viruses have emerged and caused outbreaks in different parts of India. KFD virus was initially identified in 1957 and was known to be endemic in Karnataka State while CCHF virus was first identified during 2010 in Gujarat State, India. These viruses have managed to emerge in new areas within the last decade. With changing epidemiology of these arboviruses, there is a probability of the emergence of these viruses from new areas in future. The investigations on these two diseases under the One Health focus involved early detection, quickly developing diagnostic tools, identifying stakeholders, capacity building by developing collaboration with major stakeholders to understand the epidemiology and geographical spread in domestic animal reservoirs and tick vectors in the affected areas, developing laboratory network, providing diagnostic reagents and biosafety and laboratory diagnosis training to the network laboratories to control these diseases.

Clinical Manifestations of Nipah Virus-Infected Patients Who Presented to the Emergency Department During an Outbreak in Kerala State in India, May 2018

BACKGROUND

An outbreak of Nipah virus (NiV) disease occurred in the Kozhikode district of Kerala State in India in May 2018. Several cases were treated at the emergency medicine department (ED) of the Government Medical College, Kozhikode (GMCK). The clinical manifestations and outcome of these cases are described.

METHODS

The study included 12 cases treated in the ED of GMCK. Detailed clinical examination, laboratory investigations, and molecular testing for etiological diagnosis were performed.

RESULTS

The median age of the patients was 30 years and the male to female ratio was 1.4:1.0. All the cases except the index case contracted the infection from hospitals. The median incubation period was 10 days, and the case fatality ratio was 83.3%. Ten (83.3%) patients had encephalitis and 9 out of 11 patients whose chest X-rays were obtained had bilateral infiltrates. Three patients had bradycardia and intractable hypotension requiring inotropes. Encephalitis, acute respiratory distress syndrome, and myocarditis were the clinical prototypes, but there were large overlaps between these. Ribavirin therapy was given to a subset of the patients. Although there was a 20% reduction in NiV encephalitis cases treated with the drug, the difference was not statistically significant. The outbreak ended soon after the introduction of total isolation of patients and barrier nursing.

CONCLUSION

The outbreak of NiV disease in Kozhikode in May 2018 presented as encephalitis, acute respiratory distress and myocarditis or combinations of these. The CFR was high. Ribavirin therapy was tried but no evidence for its benefit could be obtained.

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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-05865-7.

Proactive preparedness for Cat Que virus: An Orthobunyavirus existing in India

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 RT-PCR 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.

Study of Kyasanur forest disease viremia, antibody kinetics, and virus infection in target organs of Macaca radiata

The present manuscript deals with experimental infections of bonnet macaques (Macaca radiata) to study disease progression for better insights into the Kyasanur Forest Disease (KFD) pathogenesis and transmission. Experimentally, 10 monkeys were inoculated with KFD virus (KFDV) (high or low dose) and were regularly monitored and sampled for various body fluids and tissues at preset time points. We found that only 2 out of the 10 animals showed marked clinical signs becoming moribund, both in the low dose group, even though viremia, virus shedding in the secretions and excretions were evident in all inoculated monkeys. Anti-KFDV immunoglobulin (Ig)M antibody response was observed around a week after inoculation and anti-KFDV IgG antibody response after two weeks. Anaemia, leucopenia, thrombocytopenia, monocytosis, increase in average clotting time, and reduction in the serum protein levels were evident. The virus could be re-isolated from the skin during the viremic period. The persistence of viral RNA in the gastrointestinal tract and lymph nodes was seen up to 53 and 81 days respectively. Neuro-invasion was observed only in moribund macaques. Re-challenge with the virus after 21 days of initial inoculation in a monkey did not result in virus shedding or immune response boosting.

Detection of coronaviruses in Pteropus & Rousettus species of bats from different States of India

Background & objectives:

Bats are considered to be the natural reservoir for many viruses, of which some are potential human pathogens. In India, an association of Pteropus medius bats with the Nipah virus was reported in the past. It is suspected that the recently emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) also has its association with bats. To assess the presence of CoVs in bats, we performed identification and characterization of bat CoV (BtCoV) in P. medius and Rousettus species from representative States in India, collected during 2018 and 2019.

Methods:

Representative rectal swab (RS) and throat swab specimens of Pteropus and Rousettus spp. bats were screened for CoVs using a pan-CoV reverse transcription-polymerase chain reaction (RT-PCR) targeting the RNA-dependent RNA polymerase (RdRp) gene. A single-step RT-PCR was performed on the RNA extracted from the bat specimens. Next-generation sequencing (NGS) was performed on a few representative bat specimens that were tested positive. Phylogenetic analysis was carried out on the partial sequences of RdRp gene sequences retrieved from both the bat species and complete viral genomes recovered from Rousettus spp.

Results:

Bat samples from the seven States were screened, and the RS specimens of eight Rousettus spp. and 21 Pteropus spp. were found positive for CoV RdRp gene. Among these, by Sanger sequencing, partial RdRp sequences could be retrieved from three Rousettus and eight Pteropus bat specimens. Phylogenetic analysis of the partial RdRp region demonstrated distinct subclustering of the BtCoV sequences retrieved from these Rousettus and Pteropus spp. bats. NGS led to the recovery of four sequences covering approximately 94.3 per cent of the whole genome of the BtCoVs from Rousettus bats. Three BtCoV sequences had 93.69 per cent identity to CoV BtRt-BetaCoV/GX2018. The fourth BtCoV sequence was 96.8 per cent identical to BtCoV HKU9-1.

Interpretation & conclusions:

This study was a step towards understanding the CoV circulation in Indian bats. Detection of potentially pathogenic CoVs in Indian bats stresses the need for enhanced screening for novel viruses in them. One Health approach with collaborative activities by the animal health and human health sectors in these surveillance activities shall be of use to public health. This would help in the development of diagnostic assays for novel viruses with outbreak potential and be useful in disease interventions. Proactive surveillance remains crucial for identifying the emerging novel viruses with epidemic potential and measures for risk mitigation.

Kinetics of viral RNA, immunoglobulin-M & G antibodies in Kyasanur forest disease

Background & objectives:

Kyasanur forest disease (KFD) is an infectious disease discovered in Karnataka State of India in 1957; since then, the State has been known to be enzootic for KFD. In the last few years, its presence was observed in the adjoining five States of the Western Ghats of India. The present study was conducted to understand the kinetics of viral RNA, immunoglobulin M (IgM) and IgG antibody in KFD-infected humans for developing a diagnostic algorithm for KFD.

Methods:

A prospective follow up study was performed among KFD patients in Sindhudurg district of Maharashtra State, India. A total of 1046 suspected patients were tested, and 72 KFD patients were enrolled and followed for 17 months (January 2016 to May 2017). Serum samples of KFD patients were screened for viral RNA, and IgM and IgG antibodies.

Results:

KFD viral positivity was observed from 1^st to 18^th post-onset day (POD). Positivity of anti-KFD virus (KFDV) IgM antibodies was detected from 4^th till 122^nd POD and anti-KFDV IgG antibodies detected from 5^th till 474^th POD. A prediction probability was determined from statistical analysis using the generalized additive model in R-software to support the laboratory findings regarding viral kinetics.

Interpretation & conclusions:

This study demonstrated the presence of KFD viral RNA till 18^th POD, IgM antibodies till 122^nd POD and IgG till the last sample collected. Based on our study an algorithm was recommended for accurate laboratory diagnosis of KFDV infection. A sample collected between 1 and 3 POD can be tested using KFDV real-time reverse transcriptase polymerase chain reaction (RT-PCR); between 4 and 24 POD, the combination of real-time RT-PCR and anti-KFDV IgM enzyme-linked immunosorbent assay (ELISA) tests can be used; between POD 25 and 132, anti-KFDV IgM and IgG ELISA are recommended.

Outbreak Investigation of Nipah Virus Disease in Kerala, India, 2018

BACKGROUND

Nipah Virus (NiV) is a highly fatal emerging zoonotic virus and a potential threat to global health security. Here we describe the characteristics of the NiV outbreak that occurred in Kerala, India, during May-June 2018.

METHODS

We used real-time reverse transcription polymerase chain reaction analysis of throat swab, blood, urine, and cerebrospinal fluid specimens to detect NiV. Further, the viral genome was sequenced and subjected to phylogenetic analysis. We conducted an epidemiologic investigation to describe the outbreak and elucidate the dynamics of NiV transmission.

RESULTS

During 2-29 May 2018, 23 cases were identified, including the index case; 18 were laboratory confirmed. The lineage of the NiV responsible for this outbreak was closer to the Bangladesh lineage. The median age of cases was 45 years; the sex of 15 (65%) was male. The median incubation period was 9.5 days (range, 6-14 days). Of the 23 cases, 20 (87%) had respiratory symptoms. The case-fatality rate was 91%; 2 cases survived. Risk factors for infection included close proximity (ie, touching, feeding, or nursing a NiV-infected person), enabling exposure to droplet infection. The public health response included isolation of cases, contact tracing, and enforcement of hospital infection control practices.

CONCLUSION

This is the first recorded NiV outbreak in South India. Early laboratory confirmation and an immediate public health response contained the outbreak.

A virus precipitation method for concentration & detection of avian influenza viruses from environmental water resources & its possible application in outbreak investigations

Background & objectives

Avian influenza (AI) viruses have been a major cause of public health concern. Wild migratory birds and contaminated environmental sources such as waterbodies soiled with bird droppings play a significant role in the transmission of AI viruses. The objective of the present study was to develop a sensitive and user-friendly method for the concentration and detection of AI viruses from environmental water sources.

Methods

Municipal potable water, surface water from reservoirs and sea were spiked with low pathogenic AI viruses. To concentrate the viruses by precipitation, a combination of potassium aluminium sulphate with milk powder was used. Real-time reverse transcription-polymerase chain reaction was performed for virus detection, and the results were compared with a virus concentration method using erythrocytes. Drinking water specimens from poultry markets were also tested for the presence of AI viruses.

Results

A minimum of 10^1.0 EID₅₀(50% egg infectious dose)/ml spiked H5N1 and 10^1.7 EID₅₀/ml spiked H9N2 viruses were detected from spiked potable water; 10^1.0 and 10^2.0 EID₅₀/ml spiked H5N1 virus was detected from surface water and seawater samples, respectively. The present method was more sensitive than the erythrocyte-binding method as approximately 10-fold higher infectious virus titres were obtained. AI H9N2 viruses were detected and isolated from water from local poultry markets, using this method.

Interpretation & conclusions

Viability and recovery of the spiked viruses were not affected by precipitation. The present method may be suitable for the detection of AI viruses from different environmental water sources and can also be applied during outbreak investigations.

Phylogeography of Kyasanur Forest Disease virus in India (1957-2017) reveals evolution and spread in the Western Ghats region

The Kyasanur Forest Disease (KFD) has become a major public health problem in the State of Karnataka, India where the disease was first identified and in Tamil Nadu, Maharashtra, Kerala, and Goa covering the Western Ghats region of India. The incidence of positive cases and distribution of the Kyasanur Forest Disease virus (KFDV) in different geographical regions raises the need to understand the evolution and spatiotemporal transmission dynamics. Phylogeography analysis based on 48 whole genomes (46 from this study) and additionally 28 E-gene sequences of KFDV isolated from different regions spanning the period 1957-2017 was thus undertaken. The mean evolutionary rates based the E-gene was marginally higher than that based on the whole genomes. A subgroup of KFDV strains (2006-2017) differing from the early Karnataka strains (1957-1972) by ~2.76% in their whole genomes and representing spread to different geographical areas diverged around 1980. Dispersal from Karnataka to Goa and Maharashtra was indicated. Maharashtra represented a new source for transmission of KFDV since ~2013. Significant evidence of adaptive evolution at site 123 A/T located in the vicinity of the envelope protein dimer interface may have functional implications. The findings indicate the need to curtail the spread of KFDV by surveillance measures and improved vaccination strategies.

Biorisk assessment for infrastructure & biosafety requirements for the laboratories providing coronavirus SARS-CoV-2/(COVID-19) diagnosis

Novel coronavirus infection [coronavirus disease 2019 (COVID-19)] has spread to more than 203 countries of various regions including Africa, America, Europe, South East Asia and Western Pacific. The WHO had declared COVID-19 as the global public health emergency and subsequently as pandemic because of its worldwide spread. It is now one of the top-priority pathogens to be dealt with, because of high transmissibility, severe illness and associated mortality, wide geographical spread, lack of control measures with knowledge gaps in veterinary and human epidemiology, immunity and pathogenesis. The quick detection of cases and isolating them has become critical to contain it. To meet the increasing demand of the diagnostic services, it is necessary to enhance and expand laboratory capabilities since existing laboratories cannot meet the emerging demand. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a BSL-2 (Biosafety Level 2) agent and needs to be handled in biosafety cabinet using standard precautions. This review highlights minimum requirements for the diagnostic laboratories opting testing of material for the diagnosis of COVID-19 and associated biorisk to the individuals and to the community.

Infections among Contacts of Patients with Nipah Virus, India

We conducted a serosurvey of 155 healthcare workers and 124 household and community members who had close contact with 18 patients who had laboratory-confirmed Nipah virus infections in Kerala, India. We detected 3 subclinical infections; 2 persons had IgM and IgG and 1 only IgM against Nipah virus.

Nipah Virus Sequences from Humans and Bats during Nipah Outbreak, Kerala, India, 2018

We retrieved Nipah virus (NiV) sequences from 4 human and 3 fruit bat (Pteropus medius) samples from a 2018 outbreak in Kerala, India. Phylogenetic analysis demonstrated that NiV from humans was 96.15% similar to a Bangladesh strain but 99.7%–100% similar to virus from Pteropus spp. bats, indicating bats were the source of the outbreak.

Isolation and phylogenomic analysis of buffalopox virus from human and buffaloes in India

Three genome sequences of Buffalopox virus (BPVX) were retrieved from a human and two buffaloes scab samples. Phylogenomic analysis of the BPXV indicates that it shares a most recent common ancestor with Lister and closely related vaccine strains when compared to potential wild-type VACV strains (like Horsepox virus).

Nipah virus: epidemiology, pathology, immunobiology and advances in diagnosis, vaccine designing and control strategies - a comprehensive review

Nipah (Nee-pa) viral disease is a zoonotic infection caused by Nipah virus (NiV), a paramyxovirus belonging to the genus Henipavirus of the family Paramyxoviridae. It is a biosafety level-4 pathogen, which is transmitted by specific types of fruit bats, mainly Pteropus spp. which are natural reservoir host. The disease was reported for the first time from the Kampung Sungai Nipah village of Malaysia in 1998. Human-to-human transmission also occurs. Outbreaks have been reported also from other countries in South and Southeast Asia. Phylogenetic analysis affirmed the circulation of two major clades of NiV as based on currently available complete N and G gene sequences. NiV isolates from Malaysia and Cambodia clustered together in NiV-MY clade, whereas isolates from Bangladesh and India clusterered within NiV-BD clade. NiV isolates from Thailand harboured mixed population of sequences. In humans, the virus is responsible for causing rapidly progressing severe illness which might be characterized by severe respiratory illness and/or deadly encephalitis. In pigs below six months of age, respiratory illness along with nervous symptoms may develop. Different types of enzyme-linked immunosorbent assays along with molecular methods based on polymerase chain reaction have been developed for diagnostic purposes. Due to the expensive nature of the antibody drugs, identification of broad-spectrum antivirals is essential along with focusing on small interfering RNAs (siRNAs). High pathogenicity of NiV in humans, and lack of vaccines or therapeutics to counter this disease have attracted attention of researchers worldwide for developing effective NiV vaccine and treatment regimens.

Canine Distemper Virus in Asiatic Lions of Gujarat State, India

In September 2018, an epizootic infection caused by canine distemper virus emerged in an Asiatic lion population in India. We detected the virus in samples from 68 lions and 6 leopards by reverse transcription PCR. Whole-genome sequencing analysis demonstrated the virus strain is similar to the proposed India-1/Asia-5 strain.

Nipah virus: epidemiology, pathology, immunobiology and advances in diagnosis, vaccine designing and control strategies - a comprehensive review

Nipah (Nee-pa) viral disease is a zoonotic infection caused by Nipah virus (NiV), a paramyxovirus belonging to the genus Henipavirus of the family Paramyxoviridae. It is a biosafety level-4 pathogen, which is transmitted by specific types of fruit bats, mainly Pteropus spp. which are natural reservoir host. The disease was reported for the first time from the Kampung Sungai Nipah village of Malaysia in 1998. Human-to-human transmission also occurs. Outbreaks have been reported also from other countries in South and Southeast Asia. Phylogenetic analysis affirmed the circulation of two major clades of NiV as based on currently available complete N and G gene sequences. NiV isolates from Malaysia and Cambodia clustered together in NiV-MY clade, whereas isolates from Bangladesh and India clusterered within NiV-BD clade. NiV isolates from Thailand harboured mixed population of sequences. In humans, the virus is responsible for causing rapidly progressing severe illness which might be characterized by severe respiratory illness and/or deadly encephalitis. In pigs below six months of age, respiratory illness along with nervous symptoms may develop. Different types of enzyme-linked immunosorbent assays along with molecular methods based on polymerase chain reaction have been developed for diagnostic purposes. Due to the expensive nature of the antibody drugs, identification of broad-spectrum antivirals is essential along with focusing on small interfering RNAs (siRNAs). High pathogenicity of NiV in humans, and lack of vaccines or therapeutics to counter this disease have attracted attention of researchers worldwide for developing effective NiV vaccine and treatment regimens.

Emerging/re-emerging viral diseases & new viruses on the Indian horizon

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.

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.

Clinical & epidemiological significance of Kyasanur forest disease

Kyasanur forest disease (KFD) is a known viral haemorrhagic fever in India, for the last 60 years. However, in recent years, the change in epidemiological profile of the disease has suggested that it is now time to consider KFD as an emerging tropical disease in India. The preference should be to educate not only the villagers where it is being reported or detected but also to public health experts, veterinarians, forest officials and medical professionals to pay attention while seeing a patient overlapping with endemic diseases such as Japanese encephalitis, West Nile, dengue, chikungunya, malaria and tuberculosis. Although the existence of KFD is known for a long time, updated understanding of its clinical profile in humans is still limited. This article describes in detail the clinical presentation of KFD reported till date. It also highlights geographical distribution of the disease, risk factors for virus transmission, biochemical/haematological findings and control measures. There is an urgent need for research on KFD, particularly for understanding biphasic nature of illness, development of cost-effective diagnostic tools, utility of non-invasive samples for diagnosis and development of new vaccines.

Equine Encephalosis Virus in India, 2008

A virus isolated from a sick horse from India in 2008 was confirmed by next-generation sequencing analysis to be equine encephalosis virus (EEV). EEV in India is concerning because several species of Culicoides midge, which play a major role in EEV natural maintenance and transmission, are present in this country.

Crimean Congo hemorrhagic fever serosurvey in humans for identifying high-risk populations and high-risk areas in the endemic state of Gujarat, India

Background

Crimean Congo Hemorrhagic Fever (CCHF) is a highly infectious zoonotic disease of humans transmitted by Hyalomma ticks. Earlier studies have shown CCHF seroprevalence in livestock throughout India, yet sporadic outbreaks have been recorded mostly from the Gujarat state of India since 2011. Occupational vulnerability to CCHF for animal handlers, veterinarians, abattoir workers, and healthcare workers has been documented. The current study was planned to determine the seroprevalence of CCHF with an intention to identify the high -risk population and high -risk areas from Gujarat state, India.

Methods

Based on the socio-clinical data, the human population of Gujarat was divided into eight categories viz. A: CCHF affected person/house/close contact, B: Neighborhood contacts, C: Animal handlers, D: General population, E: Farmers, F: Abattoir workers, G: Veterinarian, H: Healthcare workers. A total of 4978 human serum samples were collected from 33 districts of Gujarat during year 2015, 2016 and 2017. All the samples were screened for the presence of anti-CCHFV IgG using indigenously developed anti-CCHFV IgG ELISA. Univariate regression analysis was performed to recognize significant risk factors for CCHF seropositivity.

Results

Twenty-five serum samples were found to be positive with an overall CCHF human seropositivity of 0.5% (95% CI 0.30–0.74%). Gender predisposition to CCHF prevalence was observed in males (OR: 2.80; p-value: 0.020). The risk for seropositivity increased sevenfold when a person was in contact or neighbor with a CCHF case (OR 7.02; p-value: < 0.0001). No significant difference in seropositivity was observed within different age groups. Veterinarians, healthcare workers, and control group were found to be seronegative for CCHF.

Conclusions

In-spite of CCHF sporadic outbreaks reported in Gujarat, the seropositivity for CCHF in the state was low as compared to other endemic countries. Males, close contacts and neighbors were identified as a high-risk population for CCHF infection. To recognize the high-risk area, tick screening and animal serosurvey would be a wiser choice. The study also suggests circulation and under diagnoses of CCHFV in the naïve regions of Gujarat.

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: Current concerns in India

With confirmation of Zika virus (ZIKV) presence in India, screening of a large number of febrile illness samples yielded only four positive cases. In this review, we address the current concern with context to India. The possible reasons for low level of Zika prevalence in India have been discussed, by extracting some probable explanations from previous experience of chikungunya virus-vector model/studies. In the current context, it is hypothesized that Indian mosquito strains have lower susceptibility gradient/threshold for ZIKV. The very low positivity in the humans also indicates low levels of mosquito-human-mosquito transmission cycle. There is also a need to look for the existence of any such animal cycle/sylvatic involvement in India. The recently detected four cases in India show local transmission of ZIKV suggesting that ZIKV might have been present in India since long time. The earlier vector-virus relationship studies with chikungunya suggested that in due course of time, ZIKV might become a major public health concern in the future.

Chandipura Viral Encephalitis: A Brief Review

Introduction:

In recent years, the Chandipura virus (CHPV) has emerged as an encephalitic pathogen and found associated with a number of outbreaks in different parts of India. Children under 15 years of age are most susceptible to natural infection. CHPV is emerging as a significant encephalitis, causing virus in the Indian subcontinent. Severe outbreaks caused by the virus have been reported from several parts of India.

Expalanation:

In the recent past, the noticeable association of CHPV with pediatric sporadic encephalitis cases as well as a number of outbreaks in Andhra Pradesh (2004, 2005, 2007 and 2008), Gujarat in (2005, 2009-12) and Vidarbha region of Maharashtra (2007, 2009-12) have been documented. Prevalence and seasonal activity of the virus in these regions are established by NIV through outbreak investigations, sero-survey and diagnosis of the referred clinical specimens. Recently CHPV has been isolated from pools of sand flies collected during outbreak investigations in Vidarbha region of Maharashtra. Since its discovery from India and above-mentioned activity of CHPV, it was suspected to be restricted only to India.

Conclusion:

However, CHPV has also been isolated from human cases during 1971-72 in Nigeria, and hedgehogs (Atelerix spiculus) during entomological surveillance in Senegal, Africa (1990-96) and recently referred samples from Bhutan and Nepal and from wild toque macaques (Macaca sinica) at Polonnaruwa, Sri Lanka during 1993 suggest its circulation in many tropical countries. Based on the limited study on vector related report, it appears that sandflies may be the principle vector.

Japanese Encephalitis: A Brief Review on Indian Perspectives

Introduction:

Japanese encephalitis (JE) is recently declared as a notifiable disease in India due to its expanding geographical distribution. The disease notification facilitates effective implementation of preventive measures and case management.

Expalantion:

JE is a vector-borne disease that can be prevented by vaccine administration. It is caused by Japanese encephalitis virus (JEV), belonging to family Flaviviridae. Amongst the known etiological viral encephalitis agents, it is one of the leading viral agents of acute encephalitis syndrome in many Asian countries where it is identified to cause substantial morbidity and mortality as well as disability. Globally, it is responsible for approximately 68,000 clinical cases every year.

Conclusion:

In the absence of antivirals, patients are given supportive treatment to relieve and stabilize. Amongst available control strategies; vector control is resource intensive while animal and human vaccination are the most effective tool against the disease. This review highlights recent progress focusing challenges with diagnosis and prophylactic interventions.

Complete genome sequencing of Kaisodi virus isolated from ticks in India belonging to Phlebovirus genus, family Phenuiviridae

An unknown virus was repeatedly isolated from hard tick (Haemaphysalis spinigera) during a proactive arbovirus survey in ticks conducted in 1957, in India. The virus remained uncharacterized for a long time. The passages of this virus in different vertebrate and invertebrate cells along with human and monkey-derived cell culture showed no cytopathic effect. It was identified later to be a member of Kaisodi group among Phlebovirus genus in the family Phenuiviridae (Order: Bunyavirales) by serological methods. Due to its genomic diversity, sequencing of this virus was a challenge for a while. In this study, we were able to sequence the complete genome of this virus isolate using next-generation sequencing (NGS) platform. The unknown virus was identified to be Kaisodi virus (KASDV) using NGS analysis. De novo genome assembly derived three genomic segments for the KASDV which encode for RNA-dependent RNA polymerase, glycoprotein precursor, and nucleoprotein. Functional as well as conserved domains for Kaisodi serogroup viruses were predicted and compared to a known representative of the genus Phlebovirus. The phylogenetic tree revealed its closeness to Silverwater virus, of Kaisodi serogroup with nucleotide (69%, 62%, and 61%) and amino acid (52%, 51%, and 62%) identity for L, M, and S segment, respectively. The study demonstrates the presence of a conserved motif (⁷²TRGNK⁷⁶) around the RNA binding motif region in tick-borne phleboviruses. The intergenic region encompassing the S segment of Kaisodi serogroup was GC-rich whereas the other Phlebovirus had AT-rich genome. KASDV has the largest intergenic region and larger loops, suggesting stem-loops formed due to larger loops as a possible factor for instability and cause of transcription termination. This paper also describes the real-time RT-PCR and RT-PCR assays developed and used for the detection of KASDV RNA in ticks from Karnataka, Kerala and Maharashtra State, India. The KASDV positivity observed in the recently collected tick pools indicates that the KASDV, isolated from Karnataka state in 1957, is also circulating in the adjoining Kerala state. On the basis of the current study, it should be possible to develop diagnostic assays which would facilitate an in-depth field survey exploring the veterinary and medical significance of KASDV.

Clinico-epidemiological investigation on Varicella Zoster Virus indicates multiple clade circulation in Maharashtra state, India

BACKGROUND

Varicella Zoster Virus (VZV) is consistently in circulation and shows an increase in disease burden during the spring season. Due to a wide range of clinical presentation from a vesicular rash to bleeding or neurological complications, it makes the clinical diagnosis difficult. The present study aims to understand whether the same strain of virus is responsible for the increase in the seasonal outbreaks occurring in different parts of the country with reference to the samples from Maharashtra, Rajasthan and Gujarat states of India.

MATERIALS AND METHODS

This study reports the clinico-epidemiological and laboratory findings of suspected Varicella cases. To understand the circulating clade few representative real-time Polymerase Chain Reaction (PCR) positive were analyzed by conventional PCR and partial Open Reading Frame (ORF) 22, partial ORF 38 and partial ORF 54 were sequenced to identify single nucleotide polymorphisms responsible for clade determination. Further partial glycoprotein B gene was sequenced, and a phylogenetic tree was generated.

RESULTS

A total of 50 cases from Maharashtra (Mumbai district) and referred clinical samples of Rajasthan (Barmer district; n = 12) and Gujarat States (Gandhi Nagar, Surat districts; n = 17) were tested for the presence of VZV. Vesicular rash with fever was a common clinical presentation with 82% cases having contact history with VZV positive cases, suggesting higher secondary attack rate. The vesicular fluid of all 50 cases from Mumbai revealed the presence of VZV by real-time PCR. Urine, serum and throat swab samples showed positivity by real-time PCR. Healthcare provider's samples from Rajasthan showed 36.4% [4/11] positivity. Clinical samples from Gujarat had positivity of 41.2% [7/17].

CONCLUSIONS

This study analyses the clade based circulation of VZV in three states in India and suggests different clades circulating in Maharashtra state. Health education amongst the general population is suggested to reduce the secondary cases by early diagnosis, effective isolation policies and vaccination to reduce the burden of disease.

Characterization of Unknown Orthobunya-Like Viruses from India

Next-generation sequencing (NGS) of agents causing idiopathic human diseases has been crucial in the identification of novel viruses. This study describes the isolation and characterization of two novel orthobunyaviruses obtained from a jungle myna and a paddy bird from Karnataka State, India. Using an NGS approach, these isolates were classified as Cat Que and Balagodu viruses belonging to the Manzanilla clade of the Simbu serogroup. Closely related viruses in the Manzanilla clade have been isolated from mosquitos, humans, birds, and pigs across a wide geographic region. Since Orthobunyaviruses exhibit high reassortment frequency and can cause acute, self-limiting febrile illness, these data suggest that human and livestock infections of the Oya/Cat Que/Manzanilla virus may be more widespread and/or under-reported than anticipated. It therefore becomes imperative to identify novel and unknown viruses in order to understand their role in human and animal pathogenesis. The current study is a step forward in this regard and would act as a prototype method for isolation, identification and detection of several other emerging viruses.

Identification and characterization of novel mosquito-borne (Kammavanpettai virus) and tick-borne (Wad Medani) reoviruses isolated in India

In 1954, a virus named Wad Medani virus (WMV) was isolated from Hyalomma marginatum ticks from Maharashtra State, India. In 1963, another virus was isolated from Sturnia pagodarum birds in Tamil Nadu, India, and named Kammavanpettai virus (KVPTV) based on the site of its isolation. Originally these virus isolates could not be identified with conventional methods. Here we describe next-generation sequencing studies leading to the determination of their complete genome sequences, and identification of both virus isolates as orbiviruses (family Reoviridae). Sequencing data showed that KVPTV has an AT-rich genome, whereas the genome of WMV is GC-rich. The size of the KVPTV genome is 18 234 nucleotides encoding proteins ranging 238-1290 amino acids (aa) in length. Similarly, the size of the WMV genome is 16 941 nucleotides encoding proteins ranging 214-1305 amino acids in length. Phylogenetic analysis of the VP1 gene, along with the capsid genes VP5 and VP7, revealed that KVPTV is likely a novel mosquito-borne virus and WMV is a tick-borne orbivirus. This study focuses on the phylogenetic comparison of these newly identified orbiviruses with mosquito-, tick- and Culicoides-borne orbiviruses isolated in India and other countries.

Bioinformatics characterization of envelope glycoprotein from Kyasanur Forest disease virus

Background & objectives

Kyasanur Forest disease (KFD) is a febrile illness characterized by haemorrhages and caused by KFD virus (KFDV), which belongs to the Flaviviridae family. It is reported to be an endemic disease in Shimoga district of Karnataka State, India, especially in forested and adjoining areas. Several outbreaks have been reported in newer areas, which raised queries regarding the changing nature of structural proteins if any. The objective of the study was to investigate amino acid composition and antigenic variability if any, among the envelope glycoprotein (E-proteins) from old and new strains of KFDV.

Methods

Bioinformatic tools and techniques were used to predict B-cell epitopes and three-dimensional structures and to compare envelope glycoprotein (E-proteins) between the old strains of KFDV and those from emerging outbreaks till 2015.

Results

The strain from recent outbreak in Thirthahalli, Karnataka State (2014), was similar to the older strain of KFDV (99.2%). Although mutations existed in strains from 2015 in Kerala KFD sequences, these did not alter the epitopes.

Interpretation & conclusions

The study revealed that though mutations existed, there were no drastic changes in the structure or antigenicity of the E-proteins from recent outbreaks. Hence, no correlation could be established between the mutations and detection in new geographical areas. It seems that KFDV must be present earlier also in many States and due to availability of testing system and alertness coming into notice now.

Retrospective analysis of clinical information in Crimean-Congo haemorrhagic fever patients: 2014-2015, India

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.

A mini-review of Bunyaviruses recorded in India

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.

Prevalence and spatial distribution of Ixodid tick populations in the forest fringes of Western Ghats reported with human cases of Kyasanur forest disease and monkey deaths in South India

Kyasanur forest disease (KFD) is a major tick-borne viral haemorrhagic fever caused by KFD virus (KFDV) (Flaviviridae). The disease was reported to be confined to five districts of Karnataka state India until 2011. During 2012-2016, emergence of KFD has been reported in newer areas of Karnataka and adjoining states. Therefore, survey of tick vectors was carried out in these new areas of Karnataka and adjoining states reported with monkey deaths and human cases of KFD. In all selected sites, ticks from the forest floor were collected by lint clothes using flagging method. Tick samples were tested for KFDV nucleic acid by real-time RT-PCR. A total of 4772 ticks, comprising eight species of genus Haemaphysalis and one species each of genus Amblyomma, Ixodes and Rhipicephalus was collected. Haemaphysalis spinigera, the principal vector of KFDV was the predominant tick species (59.5%) collected followed by H. turturis (8.6%). The abundance of H. spinigera ranged from 9.2 to 33.9 per man-hour in the six districts surveyed. Of 214 (4418 tick samples) pools screened by real-time RT-PCR, two pools of H. spinigera were positive for KFDV. High abundance of Haemaphysalis vectors in the six districts indicated that the districts are receptive for KFD outbreaks. KFDV was detected in the tick vectors in the new foci of the KFD. Data on tick distribution will be useful in creating KFD risk map for strengthening the ongoing preventive measures such as vaccination and supply of insect repellents to the high risk groups and intensive health education.

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.

Development of polymerase chain reaction-based diagnostic tests for detection of Malsoor virus & adenovirus isolated from Rousettus species of bats in Maharashtra, India

Background & objectives:

Bats are recognized as important reservoirs for emerging infectious disease and some unknown viral diseases. Two novel viruses, Malsoor virus (family Bunyaviridae, genus, Phlebovirus) and a novel adenovirus (AdV) (family, Adenoviridae genus, Mastadenovirus), were identified from Rousettus bats in the Maharashtra State of India. This study was done to develop and optimize real time reverse transcription - polymerase chain reaction (RT-PCR) assays for Malsoor virus and real time and nested PCR for adenovirus from Rousettus bats.

Methods:

For rapid and accurate screening of Malsoor virus and adenovirus a nested polymerase chain reaction and TaqMan-based real-time PCR were developed. Highly conserved region of nucleoprotein gene of phleboviruses and polymerase gene sequence from the Indian bat AdV isolate polyprotein gene were selected respectively for diagnostic assay development of Malsoor virus and AdV. Sensitivity and specificity of assays were calculated and optimized assays were used to screen bat samples.

Results:

Molecular diagnostic assays were developed for screening of Malsoor virus and AdV and those were found to be specific. Based on the experiments performed with different parameters, nested PCR was found to be more sensitive than real-time PCR; however, for rapid screening, real-time PCR can be used and further nested PCR can be used for final confirmation or in those laboratories where real-time facility/expertise is not existing.

Interpretation & conclusions:

This study reports the development and optimization of nested RT-PCR and a TaqMan-based real-time PCR for Malsoor virus and AdV. The diagnostic assays can be used for rapid detection of these novel viruses to understand their prevalence among bat population.

Crimean-Congo Hemorrhagic Fever in Migrant Worker Returning from Oman to India, 2016

In January 2016, a migrant worker who returned home to India after becoming ill in Oman was confirmed to have Crimean-Congo hemorrhagic fever (CCHF). Physicians should include CCHF in the differential diagnosis for patients with hemorrhagic signs and a history of recent travel to any area where CCHF is endemic or prevalent.

Kyasanur Forest Disease Prevalence in Western Ghats Proven and Confirmed by Recent Outbreak in Maharashtra, India, 2016

INTRODUCTION

Kyasanur forest disease (KFD) outbreak was confirmed in Dodamarg Taluka, Sindhudurga district (Maharashtra) in India during the year 2016. The rise in suspected KFD cases was reported in January 2016, peaked during March, and then declined gradually from April 2016. The outbreak was thoroughly investigated considering different socio-clinical parameters.

METHODS

Total, 488 suspected KFD cases were investigated using KFD specific real-time RT-PCR and anti-KFDV IgM enzyme-linked immunosorbent assay (ELISA). Sero-epidemiological survey was carried out in the affected area using anti-KFDV IgG ELISA.

RESULTS

Among suspected KFD cases, high age-specific attack rate (105.1 per 1000 persons) was observed in adults (aged 40-59 years). Out of 488 suspected KFD cases, 130 were laboratory confirmed. Of these, 54 cases were KFDV real-time RT-PCR positive, 66 cases were anti-KFDV IgM ELISA positive and 10 cases were positive by both the assays. Case fatality ratio among laboratory-confirmed KFD cases were 2.3% (3/130). Majority of laboratory-confirmed KFD cases (93.1%) had visited Western Ghats forest in Dodamarg for activities like working in cashew nut farms (79.8%), cashew nut fruit collection (76.6%), collection of firewood (68.5%) and dry leaves/grass (40.3%), etc., before the start of symptoms. Common clinical features included fever (100%), headache (93.1%), weakness (84.6%), and myalgia (83.1%). Hemorrhagic manifestations were observed in nearly one-third of the laboratory-confirmed KFD cases (28.5%). A seroprevalence of (9.7%, 72/745) was recorded in KFD-affected area and two neighboring villages (9.1%, 15/165). Serosurvey conducted in Ker village showed clinical to subclinical ratio of 6:1 in KFD-affected areas.

CONCLUSION

This study confirms the outbreak of KFD Sindhudurg district with 130 cases. Detection of anti-KFDV IgG antibodies among the healthy population in KFD-affected area during the KFD outbreak suggested the past exposure of KFD infection. This outbreak investigation has helped health authorities in adopting KFD vaccination strategy for the population at risk.