Viremia and clinical manifestations in acute febrile patients of Chikungunya infection during the 2016 CHIKV outbreak in Delhi, India

Background

Chikungunya virus (CHIKV) is an infectious agent that caused several outbreaks among different countries and affected approximately 1.3 million Indian populations. It is transmitted by Aedes mosquito-either A. albopictus or A. aegypti. Generally, the clinical manifestations of CHIKV infection involve high-grade fever, joint pain, skin rashes, headache, and myalgia. The present study aims to investigate the relationship between the CHIKV virus load and clinical symptoms of the CHIKV infection so that better patient management can be done in the background of the CHIKV outbreak as there is no licensed anti-viral drug and approved vaccines available against CHIKV.

Methods

CHIKV RTPCR positive samples (n = 18) (Acute febrile patients having D.O.F ≤ 7 days) were taken for the quantification of CHIKV viremia by Real-Time PCR. Clinical features of the febrile patients were recorded during the collection of blood samples.

Results

The log mean virus load of 18 RT-PCR-positive samples was 1.3 × 106 copies/mL (1.21 × 103-2.33 × 108 copies/mL). Among the observed clinical features, the log mean virus load (CHIKV) of the patients without skin rash is higher than in the patients with skin rash (6.61 vs 5.5, P = 0.0435).

Conclusion

The conclusion of the study was that the patients with skin rashes had lower viral load and those without skin rashes had higher viral load.

Transcriptome analysis of Huh7 cells upon Chikungunya virus infection and capsid transfection reveals regulation of distinct cellular and metabolic pathways

Chikungunya virus (CHIKV) causes persistent arthritis and neurological problems imposing a huge burden globally. The present study aims to understand the interaction mechanism of Chikungunya virus and CHIKV-capsid in Huh7 cells. The RNA-sequencing and qRT-PCR method was used for the transcript and gene profiles of CHIKV virus and CHIKV capsid alone. Transcriptional analysis showed capsid induced 1114 and 956 differentially expressed genes (DEGs) to be upregulated and downregulated respectively, while in virus, 933 genes were upregulated and 956 were downregulated. Total 202 DEGs were common in both capsid and virus; and nine were validated using qRT-PCR. Identified DEGs were found to be associated with metabolic pathways such as Diabetes, cardiac disease, and visual impairment. Further, knock-down study on one of the DEGs (MafA) responsible for insulin regulation showed low viral proteins expression suggesting a reduction in virus-infection. Thus, the study provides insight into the interplay of the virus-host factors assisting virus replication.

Screening and evaluation of approved drugs as inhibitors of main protease of SARS-CoV-2

The COVID-19 pandemic caused by SARS-CoV-2 has emerged as a global catastrophe. The virus requires main protease for processing the viral polyproteins PP1A and PP1AB translated from the viral RNA. In search of a quick, safe and successful therapeutic agent; we screened various clinically approved drugs for the in-vitro inhibitory effect on 3CLPro which may be able to halt virus replication. The methods used includes protease activity assay, fluorescence quenching, surface plasmon resonance (SPR), Thermofluor® Assay, Size exclusion chromatography and in-silico docking studies. We found that Teicoplanin as most effective drug with IC50 ~ 1.5 μM. Additionally, through fluorescence quenching Stern-Volmer quenching constant (KSV) for Teicoplanin was estimated as 2.5 × 105 L·mol-1, which suggests a relatively high affinity between Teicoplanin and 3CLPro protease. The SPR shows good interaction between Teicoplanin and 3CLPro with KD ~ 1.6 μM. Our results provide critical insights into the mechanism of action of Teicoplanin as a potential therapeutic against COVID-19. We found that Teicoplanin is about 10-20 fold more potent in inhibiting protease activity than other drugs in use, such as lopinavir, hydroxychloroquine, chloroquine, azithromycin, atazanavir etc. Therefore, Teicoplanin emerged as the best inhibitor among all drug molecules we screened against 3CLPro of SARS-CoV-2.

Evaluation of medicinal herbs as a potential therapeutic option against SARS-CoV-2 targeting its main protease

The COVID‐19 disease caused by the SARS‐CoV‐2 has emerged as a worldwide pandemic and caused huge damage to the lives and economy of more than hundred countries. As on May 10, 2020, more than 4,153,300 people stand infected from the virus due to an unprecedented rate of transmission and 282,700 have lost their lives because of the disease. In this context, medicinal plants may provide a way to treat the disease by targeting specific essential proteins of the virus. We screened about 51 medicinal plants and found that Tea (Camellia sinensis) and Haritaki (Terminalia chebula) has potential against SARS‐COV‐2 3CL^pro, with an IC₅₀ for Green Tea as 8.9 ± 0.5 μg/ml and Haritaki 8.8 ± 0.5 μg/ml. The in‐silico studies suggested that Tea component Thearubigins binds to the cysteine 145 of protease active site and could be a pharmacoactive molecule. We predict that the inhibition in protease activity may be able to halt the SARS‐CoV‐2 replication cycle and therefore, we propose Green Tea, Black Tea, and Haritaki plant extracts as potential therapeutic candidates for SARS‐CoV‐2 infection. Further investigation on role of bioactive constituents of extracts is needed to establish the molecular basis of inhibition and towards expedited drug discovery.

Evaluation of novobiocin and telmisartan for anti-CHIKV activity

Chikungunya has re-emerged as an epidemic with global distribution and high morbidity, necessitating the need for effective therapeutics. We utilized already approved drugs with a good safety profile used in other diseases for their new property of anti-chikungunya activity. It provides a base for a fast and efficient approach to bring a novel therapy from bench to bedside by the process of drug-repositioning. We utilized an in-silico drug screening with FDA approved molecule library to identify inhibitors of the chikungunya nsP2 protease, a multifunctional and essential non-structural protein required for virus replication. Telmisartan, an anti-hypertension drug, and the antibiotic novobiocin emerged among top hits on the screen. Further, SPR experiments revealed strong in-vitro binding of telmisartan and novobiocin to nsP2 protein. Additionally, small angle x-ray scattering suggested binding of molecules to nsP2 and post-binding compaction and retention of monomeric state in the protein-inhibitor complex. Protease activity measurement revealed that both compounds inhibited nsP2 protease activity with IC₅₀ values in the low micromolar range. More importantly, plaque formation assays could show the effectiveness of these drugs in suppressing virus propagation in host cells. We propose novobiocin and telmisartan as potential inhibitors of chikungunya replication. Further research is required to establish the molecules as antivirals of clinical relevance against chikungunya.

Evaluation of medicinal herbs for Anti-CHIKV activity

Chikungunya, a mosquito-borne viral disease is now a global public health problem. In tropical countries such as India, periodic chikungunya outbreaks can occur due the high prevalence of the mosquito vector, circulation of virus and the high population density. To curtail the virus in outbreak situation, a ready to use drug for chikungunya is necessary. Using the literature mentioned plant extracts, we used four assays to screen and identify indigenous plants with CHIKV inhibitory activity. Our results showed that the aqueous extract of five plant extracts exhibited anti-CHIKV activity by inhibiting viral attachment, four plant extracts exhibited replication inhibition through inhibition of helicase activity, two plants showed inhibition of protease activity. Two plant extracts showed both viral attachment inhibition and replication inhibition and also exhibited dose dependent response in virus replication inhibition assay. These findings warrant further investigation to standardize these plant extracts as antiviral formulation for chikungunya infection.

Rotavirus diversity among diarrheal children in Delhi, India during 2007-2012

Rotavirus is the leading cause of severe gastroenteritis in young children worldwide and is responsible for around 100,000 deaths in India annually. Vaccination against rotavirus (RV) is a high priority: 'ROTAVAC' an indigenous vaccine will soon be licensed in India. Surveillance to determine the impact of vaccines on emerging RV strains is required. In this study we compared the pattern of RV strains circulating in Delhi over a 5 year period with the strains over the past 12 years. The most commonly detected G genotypes were G1 (22.4%), G2 (17.2%), and G9 (25.2%) with P[4] (25.5%), P[6] (20%) and P[8] (16.9%) specificity. G12 genotype was found to be the fourth common G-type with 14.8% prevalence. Among the G-P combinations; G1P[8], G2P[4], G9P[8] and G12P[6] were detected at 7.2%, 7.2%, 5.2% and 10%, respectively. Of note, G9P[4] and G2P[6] that were rarely detected during 2000-2007 in Delhi, were observed quite frequently with prevalence of 6.5% and 3.4%, respectively. In total, 16 different G-P combinations were detected in the present study demonstrating the rich diversity of rotavirus strains in Delhi. Our data from the 12 year period indicate wide circulation of G1 and G9 genotypes in combination with P[8], G2 with P[4] and G12 with P[6] with high frequency of RV strains having rare G-P combinations in Delhi. Since the indigenous vaccine 'ROTAVAC' has a monovalent formulation, the impact of vaccines on strains and the effect of strain diversity on the efficacy of the vaccine should be monitored.