Assessment of larval and pupal indices of dengue mosquito vectors in a North-Eastern state of Tripura, India.

BACKGROUND OBJECTIVES: Dengue is a major vector-borne disease having public health importance. It is caused by Dengue Virus (DENV) and is transmitted by mosquitoes of Aedes species. With the unavailability of a vaccine, vector control remains the only preventive measure for dengue. Studies have already been conducted to establish the presence of dengue vectors in the north-eastern states of India. However, limited studies have been conducted in Tripura state. In the present study we aimed to identify the preferred breeding habitats of dengue vectors in the state. METHODS: Clinical case data of dengue since the last five years was studied and the areas with the highest case numbers were identified. Entomological investigation was carried out in areas reporting the highest number of cases. Larvae were collected from the breeding habitats using standard protocol followed by morphological and molecular identification. Further, House index (HI), Container index (CI) and Pupal index (PI) were determined. The positive pools were then processed for incrimination for the presence of dengue virus. Calculation of entomological indices was done. RESULTS: Of the total 815 containers searched, 36.80% containers were positive for mosquito larvae. Among the immature mosquito collection, 836 adults emerged and were identified as Aedes albopictus using standard taxonomic keys followed by molecular methods. HI, CI and PI, varied from 15.38% to 100%, 21% to 31.04 %, and 2.93% to 110.53% respectively. However, none of the pools was positive for dengue virus. INTERPRETATION CONCLUSION: The present study identified Ae. albopictus as a potential vector of dengue in Tripura. The study gave important insights on the preferred larval habitats and provides information on the indication of displacement of Ae. albopictus from rural to urban and semi-urban areas. However, longitudinal studies for longer time frame are necessary for any conclusive remarks.

Clinical Utility of Pro-inflammatory Oligomeric Glycoprotein Tenascin-C in the Diagnosis of Seropositive and Seronegative Rheumatoid Arthritis.

Owing to limited usefulness of Rheumatoid Factor and anti-CCP in rheumatoid arthritis, there is a need to identify a more sensitive and specific biomarker to detect rheumatoid arthritis (RA), particularly seronegative RA cases. Tenascin-C is an extracellular matrix glycoprotein, which has been implicated in the pathophysiology of RA. The objective of our study was to evaluate the diagnostic utility of serum Tenascin-C in seropositive and seronegative rheumatoid arthritis patients. We conducted a cross-sectional case control study. Sixty patients who fulfilled the ACR 2010 criteria for rheumatoid arthritis were included in the study. Thirty patients were found to be positive for RF and/or anti-CCP and 30 were negative for both RF and anti-CCP. Thirty age and gender-matched healthy subjects were taken as controls. Serum Tenascin-C was measured by quantitative sandwich enzyme immunoassay technique. The mean serum concentration of Tenascin-C in controls, seronegative and seropositive cases was 0.66 ng/ml, 20.54 ng/ml and 23.42 ng/ml, respectively. Tenascin-C levels were significantly higher in RA cases compared to controls (p < 0.0001). There was no significant difference in Tenascin-C between seropositive and seronegative cases (p = 0.603). ROC curve analysis showed a sensitivity of 96.6% and specificity of 100% with AUC of 0.98 at 2.21 ng/ml as cut-off value for diagnosing RA. Tenascin-C is elevated in both seronegative and seropositive RA, which indicates that it can be used as a sensitive marker for RA. The addition of Tenascin-C to the existing RF and anti-CCP may help in identifying a large number of patients with RA, particularly seronegative rheumatoid arthritis cases.

Global emergence of West Nile virus: Threat & preparedness in special perspective to India.

West Nile virus (WNV) is a mosquito-borne single-stranded RNA neurotropic virus within the family Flaviviridae. The virus was first reported in the West Nile province of Uganda in 1937. Since then, sporadic cases have been reported until the last two decades when it has emerged as a threat to public health. The emergence of WNV with more severity in recent times is intriguing. Considering this phenomenon, the WNV-affected areas of the world were distinguished as old versus new in a depicted world map. The present review showcases the historical and epidemiological perspectives of the virus, genetic diversity of prevailing lineages and clinical spectrum associated with its infection. Emergence of the virus has been discussed in special context to India because of co-circulation of different WNV lineages/strains along with other flaviviruses. Recent laboratory diagnostics, vaccine development and clinical management associated with WNV infection have also been discussed. Further, the research gaps, especially in context to India have been highlighted that may have a pivotal role in combating the spread of WNV.

Adaptive Neuro-Fuzzy Inference System-Based Exploration of the Interrelationships of 25-Hydroxyvitamin D, Calcium, Phosphorus with Parathyroid Hormone Production.

The rationale of the current study was to assess the prevalence of 25-hydroxyvitamin D (25-OHD) deficiency and hyperparathyroidism in South Indian population and to explore interrelationships of 25-OHD, Ca, P towards parathyroid hormone (PTH) production using adaptive neuro-fuzzy inference system (ANFIS). A total of 407 subjects (228 men 179 women) with the mean age 56.8 ± 14.1 were tested for these parameters. In view of the skewed distribution of biochemical variables, data segregation was performed in tertiles and this data was trained to generate fuzzy interference system based on subclusters. The optimized model had 358 nodes and followed 44 fuzzy rules for prediction. This ANFIS model demonstrates that the deficiency of 25-OHD and Calcium triggers PTH production. PTH elevation is significant when Phosphorus is in the highest tertile. The associations observed by this model were consistent with the Kendall-Tau correlation matrix, which revealed inverse associations of Ca with P; and Ca with PTH and positive associations of P with PTH, and Ca with 25-OHD. Furthermore, the association statistics of the machine learning algorithm were also consistent, which suggested that depletion of Ca below 8.245 mg/dl was shown to elevate PTH levels greater than 167 pg/ml when P > 4.66. Subnormal depletion in 25-OHD (9.3-16.2 ng/ml) is associated with subnormal elevation in PTH (47-73.6 pg/ml). To conclude, ANFIS and machine learning algorithm are in agreement with each other in stating that 25-OHD deficiency triggers lower calcium levels, lower calcium and higher phosphorus trigger PTH production.

Hepcidin and Ferritin: Important Mediators in Inflammation Associated Anemia in Systemic Lupus Erythematosus Patients.

Systemic Lupus Erythematosus is an autoimmune disease with female preponderance. Anemia is found in 50% of Systemic Lupus Erythematosus patients. This is a cross sectional case control study with 30 female Systemic Lupus Erythematosus patients having inflammation associated anemia (Hemoglobin < 10.0 gm/dl) and 30 age matched controls with the aim to measure serum hepcidin and ferritin levels, correlate and study their role as homeostatic regulators of iron metabolism and utility as markers. Serum transferrin, ferritin, iron, total iron binding capacity, hsCRP, liver enzymes and renal parameters were analyzed by using automated analyser. Hepcidin levels were estimated by Sandwich-ELISA method. There was significant decrease in Iron (p < 0.0001), Iron Binding capacity (p < 0.0001), Transferrin (p < 0.0001) in patients, and a significant increase in inflammatory markers: hs-CRP (p < 0.0001), ESR (p < 0.0001) compared to controls. Significant increase in both Hepcidin (p < 0.0001) and Ferritin (p < 0.0001) was observed in patients with significant positive correlation (r = 0.711) with each other. Additionally, ferritin and hepcidin significantly positively correlated with hs-CRP and ESR (r = 0.526, 0.735); (r = 0.427, 0.742) respectively. Negative correlation with hemoglobin, iron, total iron binding capacity and transferrin with hepcidin (r = - 0.80, - 0.307, - 0.553, - 0.584) and ferritin (r = -0.722, - 0.22, - 0.654, - 0.728) was observed respectively. On ROC analysis both hepcidin and ferritin has sensitivity of 96.7%, specificity of 100% at cut-off values of 110 and 49 respectively. AUC of hepcidin was 0.993 and ferritin was 0.978. We have established a positive linear correlation between Hepcidin and Ferritin levels in disease activity and the changes correlated with the inflammatory state and anemia in patients, making them important mediators and potential markers of inflammation associated anemia.

Immunogenicity & safety of a single dose of live-attenuated Japanese encephalitis vaccine SA 14-14-2 in adults.

BACKGROUND & OBJECTIVES: Japanese encephalitis (JE) caused by mosquito-borne Flavivirus is one of the leading causes of viral encephalitis in Asia. Control strategies include vector control and human vaccination. Due to lack of immunization programmes in endemic regions, there are still high mortality and morbidity. A live-attenuated SA 14-14-2 JE vaccine (LAJEV) has been licensed and used in Asian countries, including India. We report the assessment of immunogenicity and safety of the vaccine in adults during the first mass adult vaccination campaign carried out in Assam, India. METHODS: One thousand and seventy five adults (aged ≥15 yr) who received LAJEV were monitored for adverse events following immunization for one year. The safety assessment of vaccinated population was evaluated till 28 days and at 6 and 12 months. Blood samples collected from the enrolled participants were tested by plaque reduction neutralization test (PRNT 50 ) to assess the neutralizing antibody titres (NATs) before vaccination and 28 days, six and 12 months post-vaccination (PV). RESULTS: Among the 1075 vaccinated individuals, four reported minor adverse effects from 30 min to 28 days PV. Based on the pre-vaccination NAT, the study participants were categorized as seronegative, moderately seropositive and strongly seropositive. Nearly 85.5 per cent of JE seronegative participants seroconverted by 28 days PV. The geometric mean titre (GMT) in all the three groups increased by 28 days and decreased by six and 12 months PV. Nearly 60 per cent of the moderately positive individuals exhibited four-fold rise in GMT, 28 days PV. Almost 95.5 per cent of the participants in the study population remained seroprotected at the end of 12 months PV. INTERPRETATION & CONCLUSIONS: This study on immunogenicity and safety of LAJEV in adults showed that a single dose of the live-attenuated vaccine was safe and induced protective immunity to both JE seronegative and naturally seropositive adults. Further study is required to find out long term protective efficacy of this vaccine.

Chikungunya outbreak in Garo Hills, Meghalaya: An epidemiological perspective.

BACKGROUND & OBJECTIVES: Chikungunya (CHIK) fever is a mosquito-borne disease caused by chikungunya virus (CHIKV). Chikungunya infection was first reported from India in 1963 from Kolkata. We report the serological and molecular evidence of an outbreak of chikungunya in northeast India that occurred in Tura, a hilly and forested terrain in Garo Hills district of Meghalaya. METHODS: Blood samples (3 ml) collected from hospitalized patients during the outbreak were tested for IgM antibodies against CHIKV and followed up four months later. A repeat survey was carried out in the same area after four months from where cases had been reported. Blood samples were also collected from people with history of fever and body ache in the last four months. Persons showing IgM positivity against CHIKV in the repeat survey were followed up one and a half years later. All samples were also processed by RT-PCR assay for CHIK Envelope (E) 1 gene. Immature mosquitoes were collected, link reared and identified with standard keys. Virus incrimination studies were done on Aedes aegypti and Ae. albopictus mosquitoes collected during the survey. RESULTS: Fever, headache and joint pain were the primary clinical presentations. Twenty three (35.93 %) of 64 samples reported during the outbreak were IgM positive for CHIK. Three samples showed PCR amplification. All these were IgM positive. The sequenced E1 gene revealed that the strains belonged to East Central South African (ECSA) genotype. INTERPRETATION & CONCLUSIONS: Field survey done after four months revealed that some individuals still had joint pain associated with episodes of headache and fever. It could be inferred that these persons might have contracted infection during the CHIK outbreak four months ago or during the intervening period which caused persistence of sequelae. ECSA genotype was found to be involved in the outbreak. Aedes albopictus was the predominant mosquito species collected during the outbreak.

First evidence of dengue virus infection in wild caught mosquitoes during an outbreak in Assam, Northeast India.

BACKGROUND & OBJECTIVES: Dengue is one of the major public health problems worldwide, transmitted mainly by Aedes aegypti and Ae. albopictus mosquitoes. Rapid urbanisation and industrialisation have led to an increase in vector population in Northeastern states of India. In 2013, Guwahati, the capital city of Assam, India experienced an outbreak of dengue. This study was undertaken with an objective to determine infection rates of dengue viruses (DENV) in both the established vectors present in this region. METHODS: During the outbreak (2013), adults and larvae of both the vector species were collected from different container habitats found in case reporting areas and container index was also recorded. The mosquitoes were first pooled, homogenised and processed for NS1-ELISA. This was followed by RT-PCR of the mosquito pools. RESULTS: Both Ae. aegypti and Ae. albopictus were found breeding in containers with container index in the range of 29.41 to 80%. Six pools of Ae. aegypti were found to be positive for NS1 antigen. RT-PCR assay revealed positivity in only the NS1-ELISA positive pools, exhibiting circulation of serotype DENV-2. Minimum infection rate of female and male Ae. aegypti was recorded as 10.87 and 11.03 respectively. INTERPRETATION & CONCLUSION: This is the maiden report of detection of DENV in wild caught Ae. aegypti mosquitoes from Northeastern Region of India. The study also demonstrates the presence of transovarial transmission of dengue virus in this part of country. This information is useful in respect of both entomological as well as epidemiological point of view for taking appropriate vector control measures.

Evaluation of Serum Mammaglobin as an Alternative Biomarker in the Diagnosis of Breast Tumors.

Introduction Breast cancer is the most common cancer in women in India and accounts for 14% of all cancers in women. Rise in mortality is due to lack of awareness and proper screening. Mammography and presently available serum biomarkers have low sensitivity and specificity. In our quest to identify a better biomarker, we studied mammaglobin (MAM) in patients with breast cancer and benign breast tumors. Aim To evaluate serum mammaglobin in breast cancer patients and compare it with benign breast tumor patients and healthy controls. To compare it with existing biomarkers serum carcinoembryonic antigen (CEA) and cancer antigen 15-3 (CA 15-3). Materials and methods: This is a cross-sectional, case-control study of 77 subjects, of which 27 were breast cancer patients, 20 benign breast tumor patients, and 30 healthy controls. Serum CEA and CA15-3 were estimated by electrochemiluminescence immunoassay (ECLIA) and mammaglobin (MAM) by enzyme-linked immunosorbent assay (ELISA). Results Mammaglobin and CEA levels were elevated in breast cancer patients, followed by benign breast tumors when compared with controls ( P < 0.000001). Mammaglobin showed 81.5% sensitivity, 100% specificity, 100% positive predictive value (PPV), and 88.9% negative predictive value (NPV). CEA showed 88.9% sensitivity, 82.5% specificity, 77.4% PPV, and 91.7% NPV. The area under the curve was the highest for MAM (0.892), followed by CEA (0.889) and CA 15-3 (0.555). CA15-3 showed poor diagnostic efficacy. Combined receiver operating characteristic (ROC) curve of the biomarkers MAM and CEA had an AUC of 0.913. Conclusion Mammaglobin proved to be an efficacious biomarker in diagnosing breast cancer.

Seroprevalence of Dengue Infection Using IgG Capture ELISA in India, 2017-2018.

We conducted a nationally representative population-based survey in 60 districts from 15 Indian states covering all five geographic regions during 2017-2018 to estimate the age specific seroprevalence of dengue. Of the 12,300 sera collected, 4,955 were positive for IgG antibodies against dengue virus using IgG Indirect ELISA indicating past dengue infection. We tested 4,948 sera (seven had inadequate volume) positive for IgG antibodies on indirect ELISA using anti-dengue IgG capture ELISA to estimate the proportion of dengue infections with high antibody titers, suggestive of acute or recent secondary infection. Of the 4,948 sera tested, 529 (10.7%; 95% CI: 9.4-12.1) were seropositive on IgG capture ELISA. The proportions of dengue infections with high titers were 1.1% in the northeastern, 1.5% in the eastern, 6.2% in the western, 12.2% in the southern, and 16.7% in the northern region. The distribution of dengue infections varied across geographic regions, with a higher proportion of infections with high antibody titer in the northern and southern regions of India. The study findings could be useful for planning facilities for clinical management of dengue infections.

Immunity against diphtheria among children aged 5-17 years in India, 2017-18: a cross-sectional, population-based serosurvey.

BACKGROUND: Diphtheria is re-emerging as a public health problem in several Indian states. Most diphtheria cases are among children older than 5 years. In this study, we aimed to estimate age-specific immunity against diphtheria in children aged 5-17 years in India. METHODS: We used residual serum samples from a cross-sectional, population-based serosurvey for dengue infection done between June 19, 2017, and April 12, 2018, to estimate the age-group-specific seroprevalence of antibodies to diphtheria in children aged 5-17 years in India. 8309 serum samples collected from 240 clusters (122 urban and 118 rural) in 60 selected districts of 15 Indian states spread across all five geographical regions (north, northeast, east, west, and south) of India were tested for the presence of IgG antibodies against diphtheria toxoid using an ELISA. We considered children with antibody concentrations of 0·1 IU/mL or greater as immune, those with levels less than 0·01 IU/mL as non-immune (and hence susceptible to diphtheria), and those with levels in the range of 0·01 to less than 0·1 IU/mL as partially immune. We calculated the weighted proportion of children who were immune, partially immune, and non-immune, with 95% CIs, for each geographical region by age group, sex, and area of residence (urban vs rural). FINDINGS: 29·7% (95% CI 26·3-33·4) of 8309 children aged 5-17 years were immune to diphtheria, 10·5% (8·6-12·8) were non-immune, and 59·8% (56·3-63·1) were partially immune. The proportion of children aged 5-17 years who were non-immune to diphtheria ranged from 6·0% (4·2-8·3) in the south to 16·8% (11·2-24·4) in the northeast. Overall, 9·9% (7·7-12·5) of children residing in rural areas and 13·1% (10·2-16·6) residing in urban areas were non-immune to diphtheria. A higher proportion of girls than boys were non-immune to diphtheria in the northern (17·7% [12·6-24·2] vs 7·1% [4·1-11·9]; p=0·0007) and northeastern regions (20·0% [12·9-29·8] vs 12·9% [8·6-19·0]; p=0·0035). INTERPRETATION: The findings of our serosurvey indicate that a substantial proportion of children aged 5-17 years were non-immune or partially immune to diphtheria. Transmission of diphtheria is likely to continue in India until the immunity gap is bridged through adequate coverage of primary and booster doses of diphtheria vaccine. FUNDING: Indian Council of Medical Research.

Seroprevalence of chikungunya virus infection in India, 2017: a cross-sectional population-based serosurvey.

BACKGROUND: Since its re-emergence in 2005, chikungunya virus (CHIKV) transmission has been documented in most Indian states. Information is scarce regarding the seroprevalence of CHIKV in India. We aimed to estimate the age-specific seroprevalence, force of infection (FOI), and proportion of the population susceptible to CHIKV infection. METHODS: We did a nationally representative, cross-sectional serosurvey, in which we randomly selected individuals in three age groups (5-8, 9-17, and 18-45 years), covering 240 clusters from 60 selected districts of 15 Indian states spread across all five geographical regions of India (north, northeast, east, south, and west). Age was the only inclusion criterion. We tested serum samples for IgG antibodies against CHIKV. We estimated the weighted age-group-specific seroprevalence of CHIKV infection for each region using the design weight (ie, the inverse of the overall probability of selection of state, district, village or ward, census enumeration block, and individual), adjusting for non-response. We constructed catalytic models to estimate the FOI and the proportion of the population susceptible to CHIKV in each region. FINDINGS: From June 19, 2017, to April 12, 2018, we enumerated 117 675 individuals, of whom 77 640 were in the age group of 5-45 years. Of 17 930 randomly selected individuals, 12 300 individuals participated and their samples were used for estimation of CHIKV seroprevalence. The overall prevalence of IgG antibodies against CHIKV in the study population was 18·1% (95% CI 14·2-22·6). The overall seroprevalence was 9·2% (5·4-15·1) among individuals aged 5-8 years, 14·0% (8·8-21·4) among individuals aged 9-17 years, and 21·6% (15·9-28·5) among individuals aged 18-45 years. The seroprevalence was lowest in the northeast region (0·3% [95% CI 0·1-0·8]) and highest in the southern region (43·1% [34·3-52·3]). There was a significant difference in seroprevalence between rural (11·5% [8·8-15·0]) and urban (40·2% [31·7-49·3]) areas (p<0·0001). The seroprevalence did not differ by sex (male 18·8% [95% CI 15·2-23·0] vs female 17·6% [13·2-23·1]; p=0·50). Heterogeneous FOI models suggested that the FOI was higher during 2003-07 in the southern and western region and 2013-17 in the northern region. FOI was lowest in the eastern and northeastern regions. The estimated proportion of the population susceptible to CHIKV in 2017 was lowest in the southern region (56·3%) and highest in the northeastern region (98·0%). INTERPRETATION: CHIKV transmission was higher in the southern, western, and northern regions of India than in the eastern and northeastern regions. However, a higher proportion of the population susceptible to CHIKV in the eastern and northeastern regions suggests a susceptibility of these regions to outbreaks in the future. Our survey findings will be useful in identifying appropriate target age groups and sites for setting up surveillance and for future CHIKV vaccine trials. FUNDING: Indian Council of Medical Research.

Evaluation of Galectin-3 as a Novel Diagnostic Biomarker in Patients with Heart Failure with Preserved Ejection Fraction.

Background Heart failure is a complex cardiovascular disease with a variety of etiologies and heterogeneity. The N-terminal pro-B-type natriuretic peptide (NT-proBNP) value has limited usefulness in diagnosing heart failure with preserved ejection fraction (HFpEF). Aim The aim of the present study is to evaluate serum Galectin-3 as a diagnostic biomarker in patients with HFpEF and to compare Galectin-3 with NT-proBNP levels. Materials and Methods A cross-sectional case-control study including 63 cases of heart failure with ejection fraction ≥50% confirmed by echocardiography. NT-proBNP levels in serum were measured by electrochemiluminescence immunoassay and Galectin-3 levels in serum were measured by using an enzyme-linked-immunosorbent serologic assay kit. Results The median levels of serum Galectin-3 and NT-proBNP in patients were significantly higher than those of controls (26.59 vs. 5.27 and 927 vs. 49.3, p < 0.0001). A positive correlation was observed between serum levels of Galection-3 and NT-ProBNP ( r : 0.21, p = 0.048). At cut-off values of 10.1 ng/mL and 160 pg/mL, serum Galectin-3 has 77.78% sensitivity, 95% specificity with an area under the curve (AUC) of 0.93, and serum NT-proBNP has 71.43% sensitivity, 100% specificity with an AUC of 0.87, respectively, for diagnosing HFpEF. The comparison of receiver operating characteristics curves showed that Galectin-3 has better AUC compared with NT-proBNP in diagnosing HFpEF. Serum Galectin-3 showed a positive correlation with NT-proBNP and lipid parameters. Conclusion Galectin-3 with higher sensitivity and AUC can be used as a valuable biomarker for the diagnosis of HFpEF. Simultaneous testing of both Galectin-3 and NT-proBNP can further improve the detection of patients with HFpEF.

Hepatitis-B virus infection in India: Findings from a nationally representative serosurvey, 2017-18.

INTRODUCTION: India introduced a hepatitis-B (HB) vaccine in the Universal Immunization Program in 2002-2003 on a pilot basis, expanded to ten states in 2007-2008 (phase-1), and the entire country in 2011-2012 (phase-2). We tested sera from a nationally representative serosurvey conducted duing 2017, to estimate the seroprevalence of different markers of HB infection among children aged 5-17 years in India and to assess the impact of vaccination. METHODS: We tested sera from 8273 children for different markers of HB infection and estimated weighted age-group specific seroprevalence of children who were chronically infected (HBsAg and anti-HBc positive), and immune due to past infection (anti-HBc positive and HBsAg negative), and having serological evidence of HB vaccination (only anti-HBs positive). We compared the prevalence of serological markers among children born before (aged 11-17 years) and after (aged 5-10 years) introduction of HB-vaccine from phase-1 states. RESULTS: Among children aged 5-8 years, 1.1% were chronic carriers, 5.3% immune due to past infection, and 23.2% vaccinated. The corresponding proportions among children aged 9-17 years were 1.1%, 8.0%, and 12.0%, respectively. In phase-1 states, children aged 5-10 years had a significantly lower prevalence of anti-HBc (4.9% vs. 7.6%, p<0.001) and higher prevalence of anti-HBs (37.7% vs. 14.7%, p<0.001) compared to children aged 11-17 years. HBsAg positivity, however, was not different in the two age groups. CONCLUSIONS: Children born after the introduction of HB vaccination had a lower prevalence of past HBV infection and a higher prevalence of anti-HBs. The findings of our study could be considered as an interim assessment of the impact of the hepatitis B vaccine introduction in India.

Evaluation of Th1 and Th2 immune response in clinical and sub-clinical scrub typhus infection.

Scrub typhus (ST), caused by a gram negative intracellular bacteria- Orientia tsutsugamushi, is one among the leading causes of febrile illness across Southeast Asia, including India. Clinical presentation can vary from asymptomatic to severely fatal. Th1-cell mediated immunity has been suggested to play an important role against ST infection in animal models. However, human data on protective immunity are limited. The present study was undertaken to identify host immune correlates that could confer protection in individuals that remain clinically asymptomatic/sub-clinical. Serum cytokine profiling and mRNA expression levels of Th1 (TNF-α, IFN-γ, IL-2) and Th2 (IL-10, IL-6, IL-4) cytokines was studied amongst the clinical and sub-clinical infections. It was observed that a Th1/Th2 pattern is not involved in human ST infection irrespective of being a symptomatic or asymptomatic presentation. However, significant difference was observed in IL-10 serum and gene expression levels. This study suggests a possible role of IL-10 in disease phenotypic presentation. Over-production of IL-10 was found to be a significant factor contributing to the severity of the disease whereas a protective immune mechanism might exist with a low level of IL-10 in ST infection.

Differential Expression Levels of Inflammatory Chemokines and TLRs in Patients Suffering from Mild and Severe Japanese Encephalitis.

Japanese encephalitis (JE) is a vector-borne viral disease with clinical manifestations ranging from asymptomatic to severe neurological symptoms and even leading to death. The exact pathophysiology for diverse clinical spectrum of the disease is complex and has not yet been defined. Studies have postulated that during JE infection, inflammatory cytokines and chemokines are produced after the initial recognition of viral antigens through the engagement of toll-like receptors (TLR) pathways. However, there is paucity of knowledge on the expression levels of chemokines and TLRs among mild and severely affected JE patients. Hence, to better understand disease pathogenesis, we examined the mRNA expression of chemokines, CCL2 and CCL5, and their respective receptors CCR2 and CCR5 along with TLRs viz. TLR3, TLR7, TLR8, and TLR9 in context of mild and severely Japanese encephalitis virus (JEV)-infected (n = 19) and healthy (n = 19) individuals. Our study showed significant downregulation of CCL2, CCL5, CCR2, CCR5, and TLR3 by log 0.87, 1.02, 0.82, 0.68, and 0.37-fold respectively, among mild cases compared with controls. Significant difference of gene expression among mild and severe JE cases for CCL2 (p < 0.001), CCL5 (p < 0.01), and TLR7 (p < 0.05) was observed. In conclusion, our results proposes that chemokines viz. CCL2 and CCL5 along with TLR7 may be associated with degree of pathogenesis of JE and could be putative therapeutic targets for preventing severe inflammation during viral encephalitis.

Burden of dengue infection in India, 2017: a cross-sectional population based serosurvey.

BACKGROUND: The burden of dengue virus (DENV) infection across geographical regions of India is poorly quantified. We estimated the age-specific seroprevalence, force of infection, and number of infections in India. METHODS: We did a community-based survey in 240 clusters (118 rural, 122 urban), selected from 60 districts of 15 Indian states from five geographical regions. We enumerated each cluster, randomly selected (with an Andriod application developed specifically for the survey) 25 individuals from age groups of 5-8 years, 9-17 years, and 18-45 years, and sampled a minimum of 11 individuals from each age group (all the 25 randomly selected individuals in each age group were visited in their houses and individuals who consented for the survey were included in the study). Age was the only inclusion criterion; for the purpose of enumeration, individuals residing in the household for more than 6 months were included. Sera were tested centrally by a laboratory team of scientific and technical staff for IgG antibodies against the DENV with the use of indirect ELISA. We calculated age group specific seroprevalence and constructed catalytic models to estimate force of infection. FINDINGS: From June 19, 2017, to April 12, 2018, we randomly selected 17 930 individuals from three age groups. Of these, blood samples were collected and tested for 12 300 individuals (5-8 years, n=4059; 9-17 years, n=4265; 18-45 years, n=3976). The overall seroprevalence of DENV infection in India was 48·7% (95% CI 43·5-54·0), increasing from 28·3% (21·5-36·2) among children aged 5-8 years to 41·0% (32·4-50·1) among children aged 9-17 years and 56·2% (49·0-63·1) among individuals aged between 18-45 years. The seroprevalence was high in the southern (76·9% [69·1-83·2]), western (62·3% [55·3-68·8]), and northern (60·3% [49·3-70·5]) regions. The estimated number of primary DENV infections with the constant force of infection model was 12 991 357 (12 825 128-13 130 258) and for the age-dependent force of infection model was 8 655 425 (7 243 630-9 545 052) among individuals aged 5-45 years from 30 Indian states in 2017. INTERPRETATION: The burden of dengue infection in India was heterogeneous, with evidence of high transmission in northern, western, and southern regions. The survey findings will be useful in making informed decisions about introduction of upcoming dengue vaccines in India. FUNDING: Indian Council of Medical Research.