Serosurveillance of dengue infection and correlation with mosquito pools for dengue virus positivity during the COVID-19 pandemic in Tamil Nadu, India - A state-wide cross-sectional cluster randomized community-based study.

Background: Dengue is a vector-borne viral disease impacting millions across the globe. Nevertheless, akin to many other diseases, reports indicated a decline in dengue incidence and seroprevalence during the COVID-19 pandemic (2020-22). This presumably could be attributed to reduced treatment-seeking rates, under-reporting, misdiagnosis, disrupted health services and reduced exposure to vectors due to lockdowns. Scientific evidence on dengue virus (DENV) disease during the COVID-19 pandemic is limited globally. Methods: A cross-sectional, randomized cluster sampling community-based survey was carried out to assess anti-dengue IgM and IgG and SARS-CoV-2 IgG seroprevalence across all 38 districts of Tamil Nadu, India. The prevalence of DENV in the Aedes mosquito pools during 2021 was analyzed and compared with previous and following years of vector surveillance for DENV by real-time PCR. Findings: Results implicate that both DENV-IgM and IgG seroprevalence and mosquito viral positivity were reduced across all the districts. A total of 13464 mosquito pools and 5577 human serum samples from 186 clusters were collected. Of these, 3·76% of mosquito pools were positive for DENV. In the human sera, 4·12% were positive for DENV IgM and 6·4% were positive for DENV IgG. The anti-SARS-CoV-2 antibody titres correlated with dengue seropositivity with a significant association whereas vaccination status significantly correlated with dengue IgM levels. Interpretation: Continuous monitoring of DENV seroprevalence, especially with the evolving variants of the SARS-CoV-2 virus and surge in COVID-19 cases will shed light on the transmission and therapeutic attributes of dengue infection.

Seasonal distribution and upsurge of respiratory viruses among indigenous tribes with ILI and SARI in a far-flung Car Nicobar Island.

BACKGROUND: Respiratory viral illnesses among children are a prominent cause of morbidity and mortality in the developing world. The aim of this study is to understand the seasonal pattern and surge of respiratory viruses among the Nicobarese tribe. METHODS: Respiratory specimens were collected from both ARI and SARI cases attended the BJR district hospital in Car Nicobar Island, India, between 2021 and 2022. Respiratory viruses were identified from the specimens by using the qRT-PCR assay. Meteorological parameters were collected and evaluated using Microsoft Excel and SPSS 21. The significant association between the surge of respiratory viruses and each climatic parameter was evaluated. RESULTS: In this hospital-based cross-sectional study, 471 ILI cases were enrolled, and 209 of these were positive for respiratory viral infections. Of these respiratory virus infections, 201 (96.2%) were infected with a single respiratory virus infection, and 8 (3.8%) had mixed viral infections. Fever, cough, and chills were the most common symptoms of respiratory illness among this indigenous population. There was a significant link between respiratory viruses and influenza-like illness in children (below 5 years and 6 to 15 years). CONCLUSION: This prevalence study revealed that viral respiratory infections were more common in children than adults. Among these respiratory viruses, respiratory syncytial virus A (RSV) and influenza B virus were predominantly reported among tribal children up to age five years. In the year 2021, these viruses were recorded frequently during the winter season. Climate factors such as high humidity, high precipitation, moderate temperature, and moderate rainfall are found to be correlated with respiratory viral infections. This study implicates important information for preventing a further outbreak of respiratory viral infections in Car Nicobar Island.

Trichomonas vaginalis infection among married women of Andaman and Nicobar islands.

BACKGROUND: Trichomoniasis is a common sexually transmitted infection among both men and women, worldwide. The prevalence of trichomoniasis among married women in the remote Indian population is more important, yet they rarely sought treatment. This was the first-ever study conducted on the prevalence of Trichomonas vaginalis (TV) in the Andaman and Nicobar Islands. METHODS: A cross-sectional study was undertaken among married women in the Andaman Islands, India from August 2020 to July 2022. Samples were collected from the suspected women attending community health centres after obtaining informed consent. PCR assay for TV was performed using specific primers and conditions. Further, sequencing was carried out and pair-wise genetic analysis was done using MEGA version 11 to find the TV strain. RESULTS: Overall, 0.9% (nine out of 1000) TV cases were reported. The majority of infected population was below high school degrees (5/9) and was unemployed (7/9). Infected individuals never had a history of a sexually transmitted illness. Two of the ladies reported dyspareunia, and one of them had persistent pelvic pain. Of these, most of them had pelvic inflammatory disease (PID) and abnormal vaginal discharge. The pair-wise genetic distance analysis found the strain found on this island was TV G3. CONCLUSIONS: From our knowledge, this surveillance study was conducted first time in the Andaman and Nicobar Island. The detection of the TV G3 strain may be essential for understanding the prevalence of TV infection and their associated risk factors. More research is needed to understand the TV-associated risk factors among suspected patients in hospital settings.

Adenoviral Conjunctivitis in the Andaman Islands: A Clinical and Molecular Epidemiological Study.

Introduction Human adenoviruses are common causes of many acute illnesses, and keratoconjunctivitis is one of them. Acute infections, if left untreated, can progress to severity, thus causing morbidities and mortalities. It belongs to the mastadenovirus family and is characterized by seven subgenus, i.e., A-G; among those, Adenovirus D8 is the most common type associated with keratoconjunctivitis. Methodology A hospital-based study was conducted, and the samples were collected from GB Pant Hospital, Port Blair, Dr Agarwals Eye Hospital, Port Blair, from August 2017 to December 2022. Clinical data and demographic details were followed by conjunctival swab sample collection from suspected keratoconjunctivitis patients. Samples were subjected to molecular screening, and Sanger sequencing was carried out for positive samples. Results Out of 506 conjunctival samples, a prevalence of 24.9% (n=126) was observed, and the commonest type circulating among the population of Andaman was Adenovirus D8. The major symptoms associated were eye redness (87.30%, n=110), followed by watering (81.75%, n=103), eye pain (72.22%, n=91), eye itching (61.11%, n=77), and discharge (50%, n=63). Conclusion In clinical research, ocular infections are one of the underrated fields. However, the study revealed the high prevalence of adenoviral infection among the suspected patients. Thus, there is a need for proper surveillance and timely diagnosis of such infections, as their severity may lead to loss of vision.

Respiratory viruses among ethnic Nicobarese during COVID-19 pandemic.

BACKGROUND: Acute respiratory infections (ARIs) and severe acute respiratory illness (SARI) are public health burdens globally. The percentage of non-SARS CoV-2 respiratory viruses among patients having ARI and SARI who visit Car Nicobar's hospital settings is undocumented. Changes in the epidemiology of other respiratory viruses during COVID19 pandemic is being reported worldwide. METHODS: Inpatient and outpatient settings at BJR hospital, Car Nicobar Island, India, were used to conduct prospective monitoring for ARI and SARI among Nicobarese tribal members. The patients with ARI and SARI were enlisted in BJR hospital from June 2019 to May 2021. At the ICMR-NIV in Pune, duplex RT-PCR assays were used to test the presence of respiratory viruses. The prevalence of non- SARS CoV-2 respiratory viruses was measured by comparing here between pandemic and pre-pandemic periods. RESULTS: During the COVID19 pandemic, Influenza A (H3N2) and rhinovirus were predominantly reported non-SARS CoV-2 respiratory viruses while Human metapneumovirusand influenza A (H1N1)pdm09were most commonly reported in the prepandemic period. This result indicates the altered circulation of non-SARS CoV-2 during pandemic. CONCLUSIONS: A considerable proportion of respiratory infection was correlated with respiratory viruses. Prevalence of non-SARS CoV-2 respiratory viruses was high at the time of infection when compared with pre-pandemic period, at Car Nicobar Island. This study enlightened the change in circulation of other respiratory viruses among the indigenous Nicobarese tribes. Clinicians and allied medical staff should be more prudent of these respiratory infections.

Expression of heat shock proteins (HSPs) in Aedes aegypti (L) and Aedes albopictus (Skuse) (Diptera: Culicidae) larvae in response to thermal stress.

Climatic changes are responsible, to a certain extent for the occurrence and spread of arboviral pathogens world over. Temperature is one of the important abiotic factors influencing the physiological processes of mosquitoes. Several genes of heat shock protein (HSP) families are known to be expressed in mosquitoes, which aid in overcoming stress induced by elevated temperature. In order to understand expression of HSP family genes in the Andaman population of Aedes aegypti and Aedes albopictus, we used quantitative real-time polymerase chain reaction (qPCR) to examine expression levels of HSPs in response to thermal stress under laboratory and in actual field conditions. HSP genes AeaHsp26, AeaHsp83 and AeaHsc70 were examined by comparing relative transcript expression levels at 31°C, 33°C, 34°C, 37°C and 39°C respectively. Enhanced up-regulation of HSPs was evident in third instar larvae of Ae. aegypti with rise in water temperatures (31°C, 33°C, 34°C) in the containers in the nature and thermally stressed (37°C and 39°C) in laboratory conditions. In Ae. albopictus up-regulation of HSPs was observed in field conditions at 34°C only and when thermally treated at 37°C, while down regulation was evident in larvae subjected to thermal stress in laboratory at 39°C. Data on expression levels revealed that larvae of Ae. aegypti was tolerant to thermal stress, while Ae. albopictus larvae was sensitive to heat shock treatment. Statistical analysis indicated that AeaHsp83 genes were significantly up-regulated in Ae. aegypti larvae after 360min exposure to high temperature (39°C). The difference in expression levels of AeaHsp26, AeaHsc70 and AeaHsp83 genes in Ae. albopictus larvae was statistically significant between different exposure temperatures. All of these genes were significantly up-regulated at 37°C. These results indicate that AeaHsp26, AeaHsc70 and AeaHsp83 are important markers of stress and perhaps function as proteins conferring protection and enhance survival of the Andaman population of both the Aedine species. Biological implications of these findings could impact the vector competencies.

Association of Oligoadenylate Synthetase Gene Cluster and DC-SIGN (CD209) Gene Polymorphisms with Clinical Symptoms in Chikungunya Virus Infection.

Biology and pathogenesis of chikungunya virus (CHIKV) are not clearly established. Host factors play an important role in determining the progression and severity of the disease. Polymorphisms in the promoter region of CD209 gene (rs735239, rs4804803, rs2287886) and OAS1 (rs1131454 and rs10774671), OAS2 (rs15895 and rs1732778), and OAS3 (rs2285932 and rs2072136) genes were investigated in 100 patients with CHIKV infection and 101 healthy controls to find out the association of these polymorphisms with CHIKV infection. To evaluate the association of OAS and CD209 gene polymorphisms with the presence or absence of disease symptoms in CHIKV-infected patients. DNA was extracted and typed using polymerase chain reaction followed by restriction fragment length polymorphism methods. Results revealed that the allele and genotype frequencies of OAS1, OAS3, and OAS2 gene polymorphisms were not different between healthy controls and CHIKV patients. The frequency of CD209 gene G/G genotype of rs4804803 was significantly higher in CHIKV patients compared to healthy controls (p = 0.046). The present study suggests that rs4804803 GG genotype of CD209 gene is associated with susceptibility to CHIKV infection. To conclude, the present preliminary study suggests that OAS gene cluster and CD209 gene polymorphisms influence the risk of developing clinical symptoms in CHIKV-infected patients. Further follow-up studies with a large number of samples are needed to assess the role of these genes in association with post-sequela symptoms observed in CHIKV patients. A detailed research is required in these directions to understand the biology behind CHIKV infection and disease severity.

Emergence of New Delhi metallo-ß-lactamase 1 (NDM-1) producing and multidrug resistant uropathogens causing urinary tract infections in Andaman Islands, India.

The present study was undertaken to understand the distribution and the antimicrobial susceptibility patterns of the uropathogens in the remote islands of India. Patients' demographical data, urine culture results, and resistance rates were analyzed and multidrug resistant isolates were characterized. Significant bacteriuria was found in 16 (17.7%, 95% confidence interval [CI] 8.47-23.53%) samples, which includes Escherichia coli 9 (56.3%); Klebsiella pneumoniae 3 (18.8%); Enterobacter sp. 2 (12.5%) and Proteus mirabilis 2 (12.5%). The uropathogens showed a wide resistance involving 3-21 drugs with 15 different resistance patterns. Among the 16 isolates, 13 (81.3%, 95% CI 62.13-100.37%) and 11 (68.8%, 95% CI 46.04-91.46%) isolates were resistant to fluoroquinolones and third generation cephalosporins, respectively. Multiple mutations were detected in quinolone resistance determining region (QRDR) of the fluoroquinolone resistant isolates and all third generation cephalosporin resistant isolates producing extended-spectrum beta-lactamase. A total of 7 (44%, 95% CI 17.02-70.98%) isolates was found to harbor plasmid mediated quinolone resistance determinants The present study reports for the first time the presence of the New Delhi metallo-ß-lactamase (NDM-1) gene in two isolates of P. mirabilis in these islands. Detection of multidrug resistant and NDM-1 producing isolates from cases of urinary tract infection in these remote islands lends support to the belief that the existence of these highly resistant strains is perhaps more widespread than previously thought and underscores the need for immediate implementation of antibiotic policy integrated with a continuous surveillance system. The study strengthens the need for a continuous surveillance system of antibiotic resistance in these remote Islands.

HLA class II allele polymorphism in an outbreak of chikungunya fever in Middle Andaman, India.

A sudden upsurge of fever cases with joint pain was observed in the outpatient department, Community Health Centre, Rangat during July-August 2010 in Rangat Middle Andaman, India. The aetiological agent responsible for the outbreak was identified as chikungunya virus (CHIKV), by using RT-PCR and IgM ELISA. The study investigated the association of polymorphisms in the human leucocyte antigen class II genes with susceptibility or protection against CHIKV. One hundred and one patients with clinical features suggestive of CHIKV infection and 104 healthy subjects were included in the study. DNA was extracted and typed for HLA-DRB1 and DQB1 alleles. Based on the amino acid sequences of HLA-DQB1 retrieved from the IMGT/HLA database, critical amino acid differences in the specific peptide-binding pockets of HLA-DQB1 molecules were investigated. The frequencies of HLA-DRB1 alleles were not significantly different, whereas lower frequency of HLA-DQB1*03:03 was observed in CHIKV patients compared with the control population [P = 0·001, corrected P = 0·024; odds ratio (OR)  = 0, 95% confidence interval (95% CI) 0·0-0·331; Peto's OR = 0·1317, 95% CI 0·0428-0·405). Significantly lower frequency of glutamic acid at position 86 of peptide-binding pocket 1 coding HLA-DQB1 genotypes was observed in CHIKV patients compared with healthy controls (P = 0·004, OR = 0·307, 95% CI 0·125-0·707). Computational binding predictions of CD4 epitopes of CHIKV by NetMHCII revealed that HLA-DQ molecules are known to bind more CHIKV peptides than HLA-DRB1 molecules. The results suggest that HLA-DQB1 alleles and critical amino acid differences in the peptide-binding pockets of HLA-DQB1 alleles might have role in influencing infection and pathogenesis of CHIKV.

Nonstructural protein 2 (nsP2) of Chikungunya virus (CHIKV) enhances protective immunity mediated by a CHIKV envelope protein expressing DNA Vaccine.

Chikungunya virus (CHIKV) is an important emerging mosquito-borne alphavirus, indigenous to tropical Africa and Asia. It can cause epidemic fever and acute illness characterized by fever and arthralgias. The epidemic cycle of this infection is similar to dengue and urban yellow fever viral infections. The generation of an efficient vaccine against CHIKV is necessary to prevent and/or control the disease manifestations of the infection. In this report, we studied immune response against a CHIKV-envelope DNA vaccine (pEnv) and the role of the CHIKV nonstructural gene 2 (nsP2) as an adjuvant for the induction of protective immune responses in a relevant mouse challenge model. When injected with the CHIKV pEnv alone, 70% of the immunized mice survived CHIKV challenge, whereas when co-injected with pEnv+pnsP2, 90% of the mice survived viral challenge. Mice also exhibited a delayed onset signs of illness, and a marked decrease in morbidity, suggesting a nsP2 mediated adjuvant effect. Co-injection of the pnsP2 adjuvant with pEnv also qualitatively and quantitatively increased antigen specific neutralizing antibody responses compared to vaccination with pEnv alone. In sum, these novel data imply that the addition of nsP2 to the pEnv vaccine enhances anti-CHIKV-Env immune responses and maybe useful to include in future CHIKV clinical vaccination strategies.

Role of proinflammatory cytokines and chemokines in chronic arthropathy in CHIKV infection.

Chikungunya virus (CHIKV) has caused large outbreaks worldwide in recent years. Acute-phase CHIKV infection has been reported to cause mild to severe febrile illness, and in some patients, this may be followed by long-lasting polyarthritis. The mainstay of treatment includes nonsteroidal anti-inflammatory drugs and other disease-modifying agents, the use of which is based on the assumption of an immunological interference mechanism in the pathogenesis. The present study has been designed to generate preliminary evidence to test this hypothesis. The levels of 30 cytokines were estimated in serum samples of acute CHIKV-infected patients, fully-recovered patients, patients with chronic CHIKV arthritis, and controls, using a quantitative multiplex bead ELISA. The levels of the proinflammatory cytokines IL-1 and IL-6 were elevated in acute patients, but IFN-γ/ß and TNF-α levels remained stable. IL-10, which might have an anti-inflammatory effect, was also elevated, indicating a predominantly anti-inflammatory response in the acute phase of infection. Elevation of MCP-1, IL-6, IL-8, MIP-1α, and MIP-1ß was most prominent in the chronic phase. These cytokines and chemokines have been shown to play important roles in other arthritides, including epidemic polyarthritis (EPA) caused by Ross River virus (RRV) and rheumatoid arthritis (RA).The immunopathogenesis of chronic CHIKV arthritis might have similarities to these arthritides. The novel intervention strategies being developed for EPA and RA, such as IL-6 and IL-8 signaling blockade, may also be considered for chronic CHIKV arthritis.

A DNA vaccine against chikungunya virus is protective in mice and induces neutralizing antibodies in mice and nonhuman primates.

Chikungunya virus (CHIKV) is an emerging mosquito-borne alphavirus indigenous to tropical Africa and Asia. Acute illness is characterized by fever, arthralgias, conjunctivitis, rash, and sometimes arthritis. Relatively little is known about the antigenic targets for immunity, and no licensed vaccines or therapeutics are currently available for the pathogen. While the Aedes aegypti mosquito is its primary vector, recent evidence suggests that other carriers can transmit CHIKV thus raising concerns about its spread outside of natural endemic areas to new countries including the U.S. and Europe. Considering the potential for pandemic spread, understanding the development of immunity is paramount to the development of effective counter measures against CHIKV. In this study, we isolated a new CHIKV virus from an acutely infected human patient and developed a defined viral challenge stock in mice that allowed us to study viral pathogenesis and develop a viral neutralization assay. We then constructed a synthetic DNA vaccine delivered by in vivo electroporation (EP) that expresses a component of the CHIKV envelope glycoprotein and used this model to evaluate its efficacy. Vaccination induced robust antigen-specific cellular and humoral immune responses, which individually were capable of providing protection against CHIKV challenge in mice. Furthermore, vaccine studies in rhesus macaques demonstrated induction of nAb responses, which mimicked those induced in convalescent human patient sera. These data suggest a protective role for nAb against CHIKV disease and support further study of envelope-based CHIKV DNA vaccines.

Outbreak of chikungunya fever, Dakshina Kannada District, South India, 2008.

The outbreak of chikungunya fever that surfaced in India during late 2005 has affected more than 1.56 million people, spread to more than 17 states/union territories, and is still ongoing. Many of these areas are dengue- and leptospirosis-endemic settings. We carried out a cross-sectional survey in one such chikungunya-affected location in Dakshina Kannada District of Karnataka State to estimate the magnitude of the epidemic and the proportion of chikungunya virus (CHIKV) infections that remained clinically inapparent. The seropositivity for CHIKV infection was 62.2%, and the attack rate of confirmed CHIK fever was 58.3%. The proportion of inapparent CHIKV infection was 6.3%. The increasing trend in the seropositivity and attack rate of CHIKV infection with age group was statistically significant. The present study is an indicator of the magnitude of the ongoing outbreak of CHIKV infection in India that started during 2005-2006.

Clinical progression of chikungunya fever during acute and chronic arthritic stages and the changes in joint morphology as revealed by imaging.

This longitudinal follow-up study of 203 patients with serologically confirmed chikungunya (CHIK) virus infection describes the clinical features of CHIK fever during the first and tenth months of illness. During the acute stage CHIK fever presents with a wide array of symptoms. The foremost chronic symptoms at the end of a month were rheumatism (75%) and fatigue (30%). During the tenth month of follow-up the symptoms/signs observed were joint pain/swelling (46%), fatigue (13%) and neuritis (6%). The cure rate at the end of 9 months was 51%. Among the patients who had joint pain, 36% (34/94) met the American College of Rheumatology criteria to classify them as having rheumatoid arthritis. A subpopulation of the patients with joint pain (20/94) was tested for rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibody, and the joints were imaged by X-ray and magnetic resonance imaging (MRI). All tested negative for RF and one tested positive for anti-CCP. A radiolucent lesion in the X-ray was seen in the bones of five patients. The MRI findings were joint effusion, bony erosion, marrow oedema, synovial thickening, tendinitis and tenosynovitis. The study proves with relative certainty that CHIK arthritis is chronic inflammatory erosive arthritis, which has implications for management of the infection.