Rapid spread of chikungunya virus following its resurgence during 2006 in West Bengal, India

Re-emergence of Chikungunya virus infection in Eastern India

Chikungunya fever is a major public health issue in India. Re-emergence of chikungunya virus (CHIKV) in West Bengal was detected after 32 years in 2006. After 2010, this infection was in apparent decline, but in 2016 a massive outbreak affected the country. Present study was carried out to understand CHIKV infection dynamics during recent outbreaks in West Bengal, Eastern India and its implication on disease manifestations. Blood was collected from 641 symptomatic patients. Patients' sera were serologically diagnosed to detect presence of anti-chikungunya-IgM antibodies. Viral RNA was extracted; presence of CHIKV genome and its respective viral load was determined by real time quantitative reverse transcription-PCR (real-time qRT-PCR). Statistical analysis was performed using EPI INFO software. CHIKV infection was detected in 24.64% of symptomatic patients. Middle-aged patients (31-40 years) were predominantly affected; clinically, both arthralgia and joint-swelling were significantly prevalent among CHIKV-infected patients. Myalgia, joint-swelling, and arthralgic manifestation were found in significantly higher frequency among patients with high chikungunya viral load (> 10,000 copies/ml). Thus, this study clearly indicated the re-emergence of CHIKV in Eastern India. Significant presence of myalgia, joint swelling, and arthralgia among chikungunya patients with high viral load implied association of disease severity with viral load; requiring vigilance for proper management of infected patients as this disease is highly morbid in nature. However, in addition to chikungunya virus, other viral, bacterial, and protozoal infections also occur during post-monsoon season in India, having overlapping symptoms. Hence, continuous monitoring of these infections is required for better clinical management of patients.

Retrospective investigation of antibodies against chikungunya virus (CHIKV) in serum from febrile patients in Mozambique, 2009-2015: Implications for its prevention and control

Introduction

Longitudinal data and trends about chikungunya virus (CHIKV) are critical for its control, however in Mozambique very few studies were conducted over 5 decades, between 1957 and 2013. In this study, we retrospectively investigated the occurrence, geographical distribution and trend of anti-CHIKV antibodies between 2009 and 2015 in Mozambique using serum samples from febrile patients.

Methods

A total of 895 serum samples collected from febrile patients for measles and rubella surveillance between 2009 and 2015 in 127 districts of Mozambique were retrospectively tested for IgM and IgG antibodies against CHIKV using a commercially available ELISA.

Results

The median age of patients was 2 years (IQR: 1–5 years) and 44.2% (395/895) of them were female. We found that 54 (6.0%) of samples were positive for anti-IgM chikungunya, and 160 (17.9%) were positive for anti-CHIKV IgG. Antibodies against CHIKV (IgM and IgG) were identified in serum throughout 2009 to 2015. While frequency of IgG antibodies was significantly higher in 2015 as compared to other years, frequency of IgM antibodies was homogeneous between 2009 and 2015. Antibodies against CHIKV were reported in all provinces and in 84 (66.1%) of the districts studied. Frequency of IgM and IgG antibodies was not significantly similar between age groups.

Conclusion

This is the largest and longest serological screening of antibodies against CHIKV in febrile patients in Mozambique and findings from this study suggest that Mozambicans from all over the country have been silently exposed to CHIKV for several years.

Dengue infection in India: A systematic review and meta-analysis

INTRODUCTION

Dengue is the most extensively spread mosquito-borne disease; endemic in more than 100 countries. Information about dengue disease burden, its prevalence, incidence and geographic distribution is critical in planning appropriate control measures against dengue fever. We conducted a systematic review and meta-analysis of dengue fever in India.

METHODS

We searched for studies published until 2017 reporting the incidence, the prevalence or case fatality of dengue in India. Our primary outcomes were (a) prevalence of laboratory confirmed dengue infection among clinically suspected patients, (b) seroprevalence in the general population and (c) case fatality ratio among laboratory confirmed dengue patients. We used binomial-normal mixed effects regression model to estimate the pooled proportion of dengue infections. Forest plots were used to display pooled estimates. The metafor package of R software was used to conduct meta-analysis.

RESULTS

Of the 2285 identified articles on dengue, we included 233 in the analysis wherein 180 reported prevalence of laboratory confirmed dengue infection, seven reported seroprevalence as evidenced by IgG or neutralizing antibodies against dengue and 77 reported case fatality. The overall estimate of the prevalence of laboratory confirmed dengue infection among clinically suspected patients was 38.3% (95% CI: 34.8%-41.8%). The pooled estimate of dengue seroprevalence in the general population and CFR among laboratory confirmed patients was 56.9% (95% CI: 37.5-74.4) and 2.6% (95% CI: 2-3.4) respectively. There was significant heterogeneity in reported outcomes (p-values<0.001).

CONCLUSIONS

Identified gaps in the understanding of dengue epidemiology in India emphasize the need to initiate community-based cohort studies representing different geographic regions to generate reliable estimates of age-specific incidence of dengue and studies to generate dengue seroprevalence data in the country.

In silico analysis of natural compounds targeting structural and nonstructural proteins of chikungunya virus

Background: Chikungunya fever presents as a high-grade fever during its acute febrile phase and can be prolonged for months as chronic arthritis in affected individuals. Currently, there are no effective drugs or vaccines against this virus. The present study was undertaken to evaluate protein-ligand interactions of all chikungunya virus (CHIKV) proteins with natural compounds from a MolBase library in order to identify potential inhibitors of CHIKV. Methods: Virtual screening of the natural compound library against four non-structural and five structural proteins of CHIKV was performed. Homology models of the viral proteins with unknown structures were created and energy minimized by molecular dynamic simulations. Molecular docking was performed to identify the potential inhibitors for CHIKV. The absorption, distribution, metabolism and excretion (ADME) toxicity parameters for the potential inhibitors were predicted for further prioritization of the compounds. Results: Our analysis predicted three compounds, Catechin-5-O-gallate, Rosmarinic acid and Arjungenin, to interact with CHIKV proteins; two (Catechin-5-O-gallate and Rosmarinic acid) with capsid protein, and one (Arjungenin) with the E3. Conclusion: The compounds identified show promise as potential antivirals, but further in vitro studies are required to test their efficacy against CHIKV.

Evidence for natural vertical transmission of chikungunya viruses in field populations of Aedes aegypti in Delhi and Haryana states in India-a preliminary report

Aedes aegypti and Aedes albopictus are principal vectors for the transmission of chikungunya virus (CHIKV). India is a hub for both dengue and chikungunya infections and there are several reports of co-infection of dengue and chikungunya virus in the clinical scenario. The present pilot entomological survey was conducted to evaluate vertical transmission of CHIKV in Aedes field populations. Aedes immature (larvae and pupae) collection was done in 2012, over a period of six months from selected sites in Delhi and Haryana, India. The immatures collected were reared for adult emergence and species identification was done. A. aegypti male and female mosquitoes were separated and pooled collection spot-wise, RNA extracted and RT PCR performed to test for the presence of CHIKV in the pools. Container index (CI) and minimum infection rate (MIR) were estimated. From study areas that tested positive for CHIKV, adult collections were made and females upon feeding on uninfected blood in laboratory were allowed to lay eggs. The progeny that emerged from these field-collected mothers were tested for CHIKV presence. Our pilot survey showed the existence of A. aegypti population even during peak summer season in a few foci which eventually helped the mosquitoes to tide over adverse environmental conditions and with the start of rainfall, the population exploded within a short period of time. Immatures collected from field and progeny of adults collected from the field were CHIKV positive demonstrating the presence of vertical transmission of chikungunya virus in field population of A. aegypti. The present study further demonstrates the importance of identifying permanent breeding sites for proper Aedes species control.

Rheumatology in India--quo vadis?

Rheumatology has been a neglected subspecialty in India. A staggering patient load, a severely inadequate number of trained rheumatology specialists, therapeutic nihilism and limited advocacy are some of the critical challenges that confront rheumatology care, and possibly explain the high rates of reliance on complementary and alternative medicines in India. Disease spectrum and treatment patterns are not remarkably different from those in other countries, but biologic agents have limited use and are administered for short periods only. Consequently, outcomes in India do not yet match those reported in developed countries. Furthermore, the high prevalence of infectious diseases continues to be a major contributor to mortality in patients with rheumatic disorders such as systemic lupus erythematosus. Several tropical diseases with rheumatic manifestations are relevant in India, including chikungunya, brucellosis, leptospirosis, dengue and melioidosis. To address the many problems with rheumatology care in India, curricular reforms, capacity building, patient education and political support are sorely needed.

Molecular characterization of chikungunya virus circulating in urban and rural areas of West Bengal, India after its re-emergence in 2006

BACKGROUND

In the state of West Bengal, chikungunya virus (CHIKV) has re-emerged in 2006 after its last occurrence in 1963-1965 in this state. The virus rapidly affected almost every district of this state, with high morbidity. Based on complete sequences of structural region of CHIKV genome, we determined the molecular characterization of the virus circulating in this state from 2006-2012.

METHODS

CHIKV was isolated from 20 acute CHIKV RT-PCR positive serum samples in C6/36 mosquito cell line. These samples were collected from 20 patients with a clinical history of ≤2 days of fever and chikungunya-like illness. Those patients were residing in some outbreak areas in the state of West Bengal during 2006-2012. Isolation was confirmed through RT-PCR and sequencing.

RESULTS AND CONCLUSIONS

Two sub-lineages of East-central-southern African (ECSA) genotype of CHIKV strains were circulating simultaneously in this state during the study period; one type was circulating in rural areas of the state from 2006 whereas another type was isolated from the metropolitan city of Kolkata in 2011 and 2012. The mutational pattern of those CHIKV strains suggests that the transmission of the viruses might be facilitated by different species of Aedes mosquitoes. Our results represent an important first step towards understanding the circulating strains of CHIKV in the state of West Bengal with the geographical variation.

A comparative study of clinical features between monotypic and dual infection cases with Chikungunya virus and dengue virus in West Bengal, India

Chikungunya virus (CHIKV) and dengue virus (DENV) are circulating individually in the state of West Bengal, India. However, after 1965 the dual-infection caused by both viruses had not been recorded until 2010. In 2010, an investigation of the febrile cases was carried out to confirm the involvement of both viruses simultaneously. A total of 550 blood samples were tested for the detection of immunoglobulin M (IgM) antibody against both CHIKV and DENV. Serology by the enzyme-linked immunosorbent assay method confirmed that 131 (23.8%) and 104 (18.9%) patients had IgM antibody against CHIKV and DENV, respectively, whereas 68 (12.4%) had IgM antibodies against both CHIKV and DENV. Fever, joint pain, rashes, headache, myalgia, and nausea/vomiting are the common features in the case of both monotypic and dual-infection. Severe arthralgia and swelling of joints were common only in CHIKV-positive cases and abdominal pain was mainly associated with DENV infection. Diarrhea was reported only by the dual-infected patients (16.2%).