Tumor Necrosis Factor-α, CD1A and CD1E Genetic Polymorphisms in Guillain-Barré Syndrome: A Study from India.

Background: Guillain-Barré Syndrome (GBS) is an acute acquired autoimmune inflammatory disorder of peripheral nerves and roots. The pathogenesis is essentially an aberrant post-infectious immune response in a genetically susceptible host milieu. Single nucleotide polymorphisms (SNP) in genes encoding the inflammatory mediators like TNF-α, CD1A and CD1E can influence their expression and level and the susceptibility and clinical course of disease in GBS. Objective: We tried to study the susceptibility of single nucleotide polymorphisms of TNF-α and CD1 genes in Guillain-Barré Syndrome in Indian population and determine the association in terms of genotype, allele and haplotype distribution along with individual subtype, severity and clinical outcome. Methodology: In this case-control study, we investigated the single nucleotide polymorphism pattern in the promoter region of TNF-α (-308 G/A), TNF-α (-863C/A), CD1A and CD1E genes using real-time polymerase chain reaction in 75 GBS patients and analysed in comparison with 75 age and sex-matched healthy controls. Results: The findings revealed that the allelic distribution of TNF-α (-308 G/A) *A allele was associated with GBS (P value 0.04, Odds Ratio 2.03, 95% Confidence Interval 1.01-4.07). There was no association found with genotype, haplotype combination and other allele distribution for GBS in the study. CD1A and CD1E SNPs did not reveal any susceptibility for GBS. The subtype analysis did not reveal any statistical significance, except for CD1A *G allele with AMAN subtype (P value 0.026). The haplotypic combinations and mutant allele of TNF-α (-308 G/A), TNF-α (-863C/A), CD1A and CD1E were significantly associated with severe GBS in the study. However, there was no association of any SNP for mortality and survival of GBS in the study. Conclusion: TNF-α (-308 G/A)*A allele might confer genetic susceptibility for GBS in Indian population. CD1 genetic polymorphism could not be considered for susceptibility to GBS. TNF-α and CD1 genetic polymorphism did not affect mortality in GBS.

Central nervous system, spinal root ganglion and brachial plexus involvement in leprosy: A prospective study.

Background: Leprosy is primarily a disease of peripheral nerves. Some isolated case reports and case series have communicated imaging changes in the central nervous system (CNS) and brachial plexus in patients with leprosy. Objectives: To study the neuroimaging abnormalities in patients with lepra bacilli-positive neuropathy in the context of CNS, spinal root ganglion, and brachial plexus. Design: Prospective observational study. Methods: We screened newly-diagnosed patients with multibacillary leprosy presenting with neuropathy. Patients with bacilli-positive sural nerve biopsies were included in the study and subjected to magnetic resonance imaging (MRI) of the brain and spinal cord. Results: A total of 54 patients with bacteriologically confirmed multibacillary leprosy were screened; Mycobacterium leprae was demonstrated in the sural nerve biopsies of 29 patients. Five patients (5/29; 17.24%) had MRI abnormalities in CNS, spinal root ganglion, and/or brachial plexus. Three patients had MRI changes suggestive of either myelitis or ganglionitis. One patient had T2/FLAIR hyperintensity in the middle cerebellar peduncle while 1 had T2/FLAIR hyperintensity in the brachial plexus. Conclusion: CNS, spinal root ganglion, and brachial plexus are involved in patients with leprous neuropathy. Immunological reaction against M leprae antigen might be a plausible pathogenetic mechanism for brachial plexus and CNS imaging abnormalities.

Cytomegalovirus Coinfection in Critically Ill Patients with Novel Coronavirus-2019 Disease: Pathogens or Spectators?

Coronavirus disease-2019 (COVID-19) pandemic is raging all over the world. As we are delving more into management of COVID-19, certain new challenges are emerging. One of these is emergence or reactivation of viral infections belonging to Herpesviridae family, especially cytomegalovirus (CMV). Although we have come across the threat of fungal and resistant bacterial infections, experience regarding reactivation or coinfection with concomitant viral infections like CMV during the COVID pandemic is still limited. Whether CMV is a bystander or pathogen is difficult to say categorically and needs further research. In this case series, we intend to describe three patients of COVID-19 with CMV coinfections. To our knowledge, this is the first case series from India. How to cite this article: Siddiqui SS, Chatterjee S, Yadav A, Rai N, Agrawal A, Gurjar M, et al. Cytomegalovirus Coinfection in Critically Ill Patients with Novel Coronavirus-2019 Disease: Pathogens or Spectators? Indian J Crit Care Med 2022;26(3):376-380.

Molecular characterisation of Hepatitis E virus isolates from north India.

PURPOSE: Hepatitis E virus (HEV) is responsible for >50% of acute viral hepatitis (AVH) in developing countries. It has 4 major genotypes and various subtypes which vary in geographical distribution, clinical manifestations and epidemiological patterns. This study was conducted to characterise HEV isolates from north India to study the effect of host and viral factors on HEV infection. METHODS: Serum samples collected from 536 AVH patients admitted to Department of Medicine, King George's Medical University, Lucknow from July 2016 to June 2017 were screened for anti HEV IgM, anti HAV IgM, HBsAg and anti HCV antibodies using commercial ELISA kits. Samples either positive for anti HEV IgM antibodies (n â€‹= â€‹204) or negative for all 4 hepatotropic viruses (n â€‹= â€‹37) were enrolled and tested by real time PCR for HEV RNA. HEV RNA positive samples with high viral load were further subjected to nested PCR for amplification of capsid gene. Sequencing and phylogenetic analysis were performed. HEV strains isolated from this study were deposited to GenBank under accession numbers MG571274 to MG571283. RESULTS: Anti HEV IgM positivity was observed among 38% clinically suspected AVH cases. HEV RNA was detected in 31.8% seropositive HEV cases and additional 3 seronegative cases. Males outnumbered females and the most affected age group was of young adults. Maximum number of cases were seen during the months of June to September. Phylogenetic analysis showed that HEV strains in our study belonged to genotype 1a. Mortality in HEV infected pregnant females was 23.5% as compared to 2.4% in non-pregnant females. Adverse fetal outcome was recorded in 51% of HEV infected pregnancies. CONCLUSIONS: HEV genotype 1a is prevalent in our setting. HEV during pregnancy is associated with adverse maternal and fetal outcome.

Correlation of serotype-specific strain in patients with dengue virus infection with neurological manifestations and its outcome.

INTRODUCTION: Neurological manifestation of dengue virus infection is a rare entity. Serotypes commonly associated with neurological manifestation are DENV-2 and DENV-3. We plan to detect the serotypes related to the neurological presentation in dengue infection and its correlation with different neurological complications and outcome. METHODS: In this case-control study, consecutive dengue cases with different neurological manifestations were enrolled along with age and sex-matched controls (dengue patients without neurological complication). Serotyping using RT-PCR of samples of cases and controls were done. Level of correlation was analyzed with various parameters and outcomes. RESULTS: In cases out of 33 samples, 6 sample serotypes were detected, which were composed of DENV-1 (n = 2) and DENV-2 (n = 4). In controls, DENV-1 (n = 5), DENV-2 (n = 6), and DENV-3 (n = 3) were detected. When statistically correlated, no significant association was found in cases and controls with dengue virus serotype. The frequency of serotype 2 was higher in hypokalemic paralysis cases than non-hypokalemic paralysis cases and the difference was significant (p < 0.05). The outcome was good (mRS < 3) in all the cases where serotypes were detected, but on statistical correlation, it was not found significant (p > 0.05). CONCLUSION: DENV-1 and DENV-2 are associated with neurological manifestation of dengue infection, which is different from the existing literature, where DENV-2 and DENV-3 are reported. The detection of DENV serotype will help in predicting and best management of neurological complication. The serotype 2 of dengue virus is more commonly associated with dengue-associated hypokalemic paralysis than other neurological complication (p < 0.05). There is no significant association of serotypes with outcome or mortality.

Unusual clinical presentations of scrub typhus, a neglected tropical disease: A case series from north India.

BACKGROUND & OBJECTIVES: Scrub typhus is a neglected tropical disease common in Asia and Africa. It usually presents with non-specific symptoms like fever, rashes, and lymphadenopathy. It has a varying range of clinical picture that often leads to misdiagnosis and initiation of non-specific treatment. This disease is thus associated with high morbidity and mortality. We aim to highlight the uncommon presentations of this common disease to create awareness regarding the unusual presentations of scrub typhus. METHODS: This prospective study was performed over a period of two months enrolling eleven adult patients with serological evidence of anti-scrub typhus IgM antibodies. RESULTS: All enrolled 11 cases [5 males (45.5%) and 6 females (54.5%)] were positive for anti-ST IgM antibodies and negative for other tested microbial agents. 7/11 (63.6%) patients were admitted with a clinical diagnosis of acute encephalitis syndrome (AES as per standard WHO definition), 3/11 (27.3%) patients presented with jaundice and 1/11 (9.1%) patients presented with rashes. Two out of 7 (28.6%) AES cases had developed peripheral gangrene of extremities. INTERPRETATION & CONCLUSION: Scrub typhus is a common tropical disease that can have various unusual clinical presentations like meningoencephalitis, vasculitis, acute kidney injury, jaundice, MODS. It closely mimics other infective etiologies making its diagnosis difficult. A high index of suspicion and clinical awareness is required in clinical practice to identify the different presentations of this disease so that early treatment can be initiated to reduce morbidity and mortality associated with this disease.

Polymorphisms in vitamin D receptor, toll-like receptor 2 and Toll-Like receptor 4 genes links with Dengue susceptibility.

Host genetic factors are known to determine disease susceptibility in dengue virus infection. Therefore, in this study association of gene polymorphisms of Vitamin D Receptor [rs731236 (Taq) and rs7975232 (Apa1)], Toll-like receptor 2 [rs5743708 (Arg735Gln) and rs5743704 (Pro631His)] and Toll-like receptor 4 [rs4986790A/G(Asp299Gly13843) and rs4986791 C/T(Thr399Ile)] were studied in cases with dengue as compared to controls. Total 98 cases of confirmed dengue virus infection and 98 age, sex and geographically matched healthy controls were enrolled and their genetic polymorphisms for the above mentioned regions were studied by Sanger sequencing. Mutant genotypes CC of VDR rs731236 (Taq1) [(OR 3.808, p value =0.02, CI 1.160-12.498)], GG of VDR rs7975232 (Apa1) [(OR 3.485, p value =0.02, CI 1.162-10.45)] and heterozygous genotypes of TLR4 rs4986790 A/G Asp299Gly [OR 2.40, p value= 0.02, CI 1.12-5.14], TLR4 rs4986791 C/T Thr399Ile [OR 2.09, p value=0.02, CI 1.12-5.14] were found to be significantly more in cases with dengue virus infection as compared to the controls. Also, at these positions mutant alleles were observed in significantly higher number of cases than controls. The values for C allele at VDR rs731236 (Taq1) were OR 1.86, p value 0.009, CI 1.162-3.001; for allele G at rs7975232( Apa1) were OR 2.71, p value 0.006, CI 1.196-2.98 for allele G at TLR4s rs4986790 A/G Asp299Gly were OR 2.35, p value 0.009, CI 1.23-4.50 and for allele T at rs4986791 C/T Thr399Ile were OR 2.36, p value=0.006, CI 1.28-4.38. VDR and TLR4 but not TLR2 gene polymorphisms were found to be associated with dengue susceptibility in Indian population.

Effect of siRNA targeting dengue virus genes on replication of dengue virus: an in vitro experimental study.

Dengue is a notorious viral infection, which affects a large segment of world populations in absence of vaccines and anti-viral treatment. The current study evaluates role of effective siRNA in dengue virus replication. Eight siRNA were synthesized against five different genes (Capsid, CprM, NS1, NS3 and NS5) of all serotypes of dengue virus. All serotype of DV were transfected with all synthesized siRNA in vitro, using BHK-21 cell lines. Culture fluid from test and control was tested by Real time PCR for CT value comparison in siRNA treated cell line (test) and untreated cell line (controls). Percent knockdown (%KD) was calculated by ∆∆CT methods to know the difference in test and control CT value. It was found that siRNA targeted against capsid gene worked best and showed inhibition of all four DV serotypes. DV-1, DV-2, DV-3 and DV-4 showed 93.8%, 99.3%, 87.5% and 93.8% knock down (%KD) respectively by siRNA targeted against capsid gene. Additionally, Si2 (target CprM gene 60-899) and Si 6 (target NS1 gene 3007-3025) were also showing inhibition of replication. Most serotypes of DV (with few exceptions) were not inhibited by siRNA targeted against NS-1, NS-3, and NS-5 genes. Animal studies using siRNAs are warranted to establish their therapeutic role.

Study of Single Nucleotide Polymorphisms in Endosomal Toll-Like Receptors-3, 7, and 9 Genes in Patients With Dengue: A Case-Control Study.

Introduction The endosomal toll-like receptors (TLR) TLR3, TLR7, and TLR9 are localized in immune cells, recognize the viral pattern associated molecular pattern (PAMPs), and start signaling cascades for immune defense response and genetic factor is known to affect the dengue virus infection therefore in our study we study the association of endosomal Toll-like receptors 3 polymorphism rs3775291, rs3775290, and rs3775296 with rs179008 A/T and rs179009C/T polymorphisms of TLR7 and rs187084 (C/T), rs5743836 (C/T) of TLR9 gene with dengue and controls. Materials and methods Ninety-eight cases of dengue virus (DV) infection and 98 healthy controls were enrolled. Clinical details were recorded and cases were classified as severe or non-severe dengue, based on WHO 2009 classification. Genotypes were determined by Sanger sequencing using the genetic analyzer. Results An increased risk of DV infection was observed in cases as compared to controls, with TLR 3 rs3775291 CT genotype (OR = 4.34, P-value: 0.031, CI = 1.14-16.5), Likewise in TLR7 rs179008 AT (OR = 2.12, P-value: 0.034, CI = 1.06-4.26) and rs179009 CT (OR = 2.04, P-value: 0.040, CI = 1.03-4.05) same as in TLR9 rs187084 CT (OR = 1.97, P-value: 0.046, CI = 1.013-3.84) and rs5743836 (OR = 2.38, P-value: 0.009, CI = 1.24-5.57). In the above polymorphisms, mutant allele was observed in a significantly higher number in cases. The values are: for TLR3 rs3775291 T allele (OR 2.167, CI = 1.3-3.61, P-value: 0.003). TLR7 rs179008 T allele (OR 1.90, P-value: 0.021, CI = 1.07-3.35) and in TLR9 rs187084 (OR 1.91, P-value: 0.014, CI = 1.137-3.24) rs5743836 (OR 2.29, P-value: 0.0018, CI = 1.36-3.87). No significant association was observed in the genotypic frequency of severe versus non-severe dengue. Conclusion TLR3, 7, and 9 gene polymorphism might confer host genetic susceptibility to dengue in the North Indian population.

Feasibility, efficiency & effectiveness of pooled sample testing strategy (pooled NAAT) for molecular testing of COVID-19.

BACKGROUND & OBJECTIVES: During the current COVID-19 pandemic, a large number of clinical samples were tested by real-time PCR. Pooling the clinical samples before testing can be a good cost-saving and rapid alternative for screening large populations. The aim of this study was to compare the performance characteristics, feasibility and effectiveness of pooling nasal swab and throat swab samples for screening and diagnosis of SARS-CoV-2. METHODS: The pool testing was applied on a set of samples coming from low COVID-19 positivity areas. A total of 2410 samples were tested in pools of five samples each. A total of five pools of five samples each were generated and tested for E gene. RESULTS: Of the total of 482 pools (2410 samples) 24 pools flagged positive. Later on pool de-convolution, a total of 26 samples were detected as positive for COVID-19, leading to positivity of about one per cent in the test population. For the diagnosis of individual samples, the pooling strategies resulted in cost savings of 75 per cent (5 samples per pool). INTERPRETATION & CONCLUSIONS: It was observed that testing samples for COVID-19 by reverse transcription (RT)- PCR after pooling could be a cost-effective method which would save both in manpower and cost especially for resource-poor countries and at a time when test kits were short in supply.

SARS-CoV-2 -RNA persists longer in faecal sample as compared to nasal and throat swab samples of COVID-19 patients'; an observational study.

The route of transmission of Novel SARS-CoV-2 virus is ambiguous. In this regard we planned a study to find out SARS-CoV-RNA shedding in various clinical samples of 9 COVID-19 positive patients. SARS-CoV-RNA was detected in nasal swab (NS), throat swab (TS) and faecal sample but was not detected in serum and urine samples. We also report that SARS-CoV-2-RNA persisted in faeces for >20 days. Persistence of faecal RNA might impose challenge in infection control and the disease may spread to household contacts if discharged. Perineal cleaning and hygiene may be advised at the time of vaginal delivery.

Severity of dengue illness and presence of anti DV IgG in serum of laboratory confirmed dengue cases.

BACKGROUND & OBJECTIVES: Presence of dengue is reported from India since 1960s. Secondary dengue infection may be more severe than primary, hence, distinction between primary and secondary dengue is essential. A way to detect secondary dengue is demonstration of anti DV IgG in patients' serum. In this study we explored the association of dengue severity with anti DV IgG positivity. METHODS: Laboratory confirmed cases of dengue (positive for anti DV IgM/ NS-1 Antigen/ DV -RNA), presenting to the hospital within 7 days of illness, were consecutively enrolled for a period of one month (September 1-30, 2018) and were tested for anti DV IgG in their serum. All PCR positive samples were serotyped. Cases positive for anti-dengue IgG were labeled as secondary cases. Clinical details were collected to assess the severity of illness. Association of dengue severity with anti DV IgG positivity was calculated. RESULTS: Of the 128 dengue positive cases, 89 (69.5%) were anti DV IgM positive, 72 (56.3%) were Dengue NS-1 positives and 37 (28.9%) were DV-RNA positive. Only 39 (30.5%) cases were having detectable anti-dengue IgG in their serum (secondary dengue). Anti-dengue IgM positivity was significantly higher in secondary dengue cases. No association of anti DV IgG positivity was seen with severity of dengue illness. INTERPRETATION & CONCLUSION: No association of IgG positivity with severity of illness was seen. D4 serotype is first time reported from Uttar Pradesh, India.

Human parvovirus 4: An emerging etiological agent in cases presenting with influenza like illness.

This study was planned to study the association of parvovirus 4 (PARV4) with Influenza-like illness (ILI). A total of 1111 patients with a clinical diagnosis of ILI and 220 healthy controls were tested for Influenza A/HINI/and H3N2, Influenza B, and PARV4. Further sequencing was done to analyze the genotype distribution of parvovirus 4. Influenza A/HINI, A/H3N2, and B were detected in 334 (30.06%), 9 (0.81%), and 10 (0.9%) cases respectively. PARV4 was detected in 135 (12.15%) cases and one healthy control. Parvovirus 4 was significantly higher in cases as compared to controls (relative risk, 30.77%; p < .0006). Sequencing of 20 isolates suggests the dominance of genotype 2 in our region.

Pooled testing for COVID-19 diagnosis by real-time RT-PCR: A multi-site comparative evaluation of 5- & 10-sample pooling.

BACKGROUND & OBJECTIVES: Public health and diagnostic laboratories are facing huge sample loads for COVID-19 diagnosis by real-time reverse transcription-polymerase chain reaction (RT-PCR). High sensitivity of optimized real-time RT-PCR assays makes pooled testing a potentially efficient strategy for resource utilization when positivity rates for particular regions or groups of individuals are low. We report here a comparative analysis of pooled testing for 5- and 10-sample pools by real-time RT-PCR across 10 COVID-19 testing laboratories in India. METHODS: Ten virus research and diagnostic laboratories (VRDLs) testing for COVID-19 by real-time RT-PCR participated in this evaluation. At each laboratory, 100 nasopharyngeal swab samples including 10 positive samples were used to create 5- and 10-sample pools with one positive sample in each pool. RNA extraction and real-time RT-PCR for SARS-CoV-2-specific E gene target were performed for individual positive samples as well as pooled samples. Concordance between individual sample testing and testing in the 5- or 10-sample pools was calculated, and the variation across sites and by sample cycle threshold (Ct) values was analyzed. RESULTS: A total of 110 each of 5- and 10-sample pools were evaluated. Concordance between the 5-sample pool and individual sample testing was 100 per cent in the Ct value ≤30 cycles and 95.5 per cent for Ctvalues ≤33 cycles. Overall concordance between the 5-sample pooled and individual sample testing was 88 per cent while that between 10-sample pool and individual sample testing was 66 per cent. Although the concordance rates for both the 5- and 10-sample pooled testing varied across laboratories, yet for samples with Ct values ≤33 cycles, the concordance was ≥90 per cent across all laboratories for the 5-sample pools. INTERPRETATION & CONCLUSIONS: Results from this multi-site assessment suggest that pooling five samples for SARS-CoV-2 detection by real-time RT-PCR may be an acceptable strategy without much loss of sensitivity even for low viral loads, while with 10-sample pools, there may be considerably higher numbers of false negatives. However, testing laboratories should perform validations with the specific RNA extraction and RT-PCR kits in use at their centres before initiating pooled testing.

Molecular characterization of hepatitis A virus circulating in Uttar Pradesh, India: A hospital-based study.

Background & objectives: Hepatitis A is prevalent worldwide and is among the leading cause of acute viral hepatitis in India. Major geographical differences in endemicity of hepatitis A are closely related to hygienic and sanitary conditions and other indicators of the level of socio-economic development. The present study was aimed to know the seropositivity prevalence and predominant circulating strain of HAV in a north India. Methods: Patients with acute viral hepatitis were enrolled. Blood samples were collected over a period of one year from June 2016 to May 2017. Serum samples were tested for anti-immunoglobulin M (IgM) HAV antibodies. The seropositive samples were analyzed for HAV-RNA by real-time reverse transcription-polymerase chain reaction (RT-PCR). Samples detected on molecular assay were subjected to conventional semi-nested RT-PCR for VP1 gene. Further sequencing of amplified RT-PCR products was done, and data were analyzed. Results: A total of 1615 patients were enrolled, and serum samples were collected and tested. The male:female ratio was 1.3:1 with a mean age of 24.31±17.02 yr (range 0-83 yr). Among these, 128 (7.93%) were positive for anti-HAV IgM antibodies; 41.63 per cent of seropositive patients were in their childhood or early adolescent age group. Of all seropositive samples, 59 (46.09%) were positive for HAV RNA. Genotyping sequencing of 10 representative strains was carried out, and the circulating genotype was found to be IIIA. The nucleotide sequences showed homology among the strains. Interpretation & conclusions: Our results showed that hepatitis A was a common disease in children with IIIA as a circulating genotype in this region. In approximately 50 per cent of cases, HAV RNA could be detected. Higher number of HAV IgM-seropositive cases was observed during monsoon period.

Second Line Injectable Drug Resistance and Associated Genetic Mutations in Newly Diagnosed Cases of Multidrug-Resistant Tuberculosis.

Aim: To investigate the phenotypic and genotypic profile of multidrug-resistant (MDR) Mycobacterium tuberculosis (MTB) clinical isolates with reference to second-line injectable drugs (SLIDs). Methods: A total of 110 MTB isolates, recovered consecutively from confirmed MDR-TB patients between March and June 2016, were included in this study. Phenotypic drug susceptibility testing against SLIDs (Kanamycin, Amikacin, and Capreomycin) and Ofloxacin (OFX) was performed using the MGIT 960 system. For genotypic analysis, SLID/(s) resistant (n = 13) and susceptible isolates (n = 26) were subjected to PCR and DNA sequencing for rrs, eis (promoter region), and tlyA loci of MTB. Furthermore, the identified genetic mutations were analyzed with respect to its significance in detecting phenotypic resistance. Result: Among the 110 analyzed isolates, phenotypic resistance to OFX, SLIDs, and to both was 59.1%, 11.8%, and 10.0%, respectively. Out of a total 13 SLID/(s) resistant isolates, 10 had mutations (including two novel mutations) in one or more of the targeted genes. Only one SLID susceptible MTB isolate showed mutation in the targeted region. In SLID resistant isolates, most frequent mutation detected was C-12T under eis promoter region (46.1%). Conclusion: Mutations in rrs, eis, and tly A loci together are important in predicting SLID resistance in MTB isolates. Future molecular epidemiology studies are needed to have more insight into frequency and clinical relevance of novel mutations identified in this study.

Upsurge of chikungunya cases in Uttar Pradesh, India.

BACKGROUND & OBJECTIVES: Chikungunya (CHIK) re-emerged in India in 2006 after a gap of three decades. In Uttar Pradesh (UP), <100 confirmed cases per million were reported during this outbreak. Based on an upsurge of CHIK cases at UP, this retrospective study was conducted to investigate clinical and serological profile of CHIK cases in UP. METHODS: A retrospective study was done on all clinically suspected CHIK cases that had been tested by ELISA for anti-CHIK virus IgM antibodies from September 2012 to December 2017. Based on clinical features, a subset of patients had earlier been tested serologically for dengue and Japanese encephalitis (JE). RESULTS: Of the 3240 cases enrolled, 771 (23.8%) were seropositive. Patients had a range of clinical manifestations with seropositivity highest in those exhibiting arthralgia with fever (40%), followed by fever of unknown origin (FUO) (22%), encephalitis (13%) and fever with rash (12%). Cases (total, seropositive) increased over 20-fold in 2016 (1389, 412) and 2017 (1619, 341), compared to 2012-2015. Nearly a third of dengue serology-positive cases and a fifth of JE serology-positive cases were co-positive for CHIKV. INTERPRETATION & CONCLUSIONS: Archival data from 2006-2011 and data from this study (2012-2017) indicated that UP experienced first CHIK outbreak in the decade in 2016, as part of a large-scale upsurge across northern India. CHIK should be considered as a differential diagnosis in patients presenting with fever of unknown origin or fever with rash or acute encephalitis, in addition to classical arthralgia.