Containment strategies for COVID-19 in India: lessons from the second wave.

INTRODUCTION: The COVID-19 pandemic in India has resulted in mass destruction in the form of second wave.Indian citizens and government were badly affected and were left constrained with basic medical facilities in treating the heavy load of patients. The possibility of reemergence of virulent strains of SARS-CoV-2 still exists. AREA COVERED: In this article, we tend to discuss why India is at high risk to be to be affected by the other waves and what strategies could be implemented to contain the viral spread. It provides these insights with reference to the gaps and the lessons learnt from the second wave along with the possible solutions to tackle these problems that were not effectively handled during the previous episodes of viral spread. We propose strategies for implementing effective vaccination programs, focus on speeding up different ways of diagnosis, management of essential hospital aids, prevention from vaccine escape mutant strains  and implementation of COVID-appropriate behavior in rural areas of India. EXPERT OPINION: This article has significance to the researchers and government officials in understanding the gaps that led to COVID-19 second wave in India and provides an opportunity to improve on certain areas for handling the future waves with more vigilance.Abbreviations: COVID-19 - Coronavirus disease 2019; SARS-COV-2 - severe acute respiratory syndrome - Coronavirus 2; δ - Delta variant; δ+ - Delta plus variant; WHO - World Health Organization; RT -PCR - Reverse transcription PCR; IFN-1 - Interferon 1; VOCs - Variants of concern; HCWs - healthcare workers.

Molecular characterization and polymorphisms of butyrylcholinesterase in cynomolgus macaques.

BACKGROUND: Butyrylcholinesterase (BChE), an enzyme essential for drug metabolism, has been investigated as antidotes against organophosphorus nerve agents, and the efficacy and safety have been studied in cynomolgus macaques. BChE polymorphisms partly account for variable BChE activities among individuals in humans, but have not been investigated in cynomolgus macaques. METHODS: Molecular characterization was carried out by analyzing primary sequence, gene, tissue expression, and genetic variants. RESULTS: In cynomolgus and human BChE, phylogenetically closely related, amino acid residues important for enzyme function were conserved, and gene and genomic structure were similar. Cynomolgus BChE mRNA was most abundantly expressed in liver among the 10 tissue types analyzed. Re-sequencing found 26 non-synonymous genetic variants in 121 cynomolgus and 23 rhesus macaques, indicating that macaque BChE is polymorphic, although none of these variants corresponded to the null or defective alleles of human BChE. CONCLUSIONS: These results suggest molecular similarities of cynomolgus and human BChE.

Phytochemical Analysis, Identification and Quantification of Antibacterial Active Compounds in Betel Leaves, Piper betle Methanolic Extract.

BACKGROUND AND OBJECTIVE: The problems of bacterial diseases in aquaculture are primarily controlled by antibiotics. Medicinal plants and herbs which are seemed to be candidates of replacements for conventional antibiotics have therefore gained increasing interest. Current study was performed to investigate the presence of phytochemical constituents, antibacterial activities and composition of antibacterial active compounds in methanolic extract of local herb, Piper betle . METHODOLOGY: Qualitative phytochemical analysis was firstly carried out to determine the possible active compounds in P. betle leaves methanolic extract. The antibacterial activities of major compounds from this extract against nine fish pathogenic bacteria were then assessed using TLC-bioautography agar overlay assay and their quantity were determined simultaneously by HPLC method. RESULTS: The use of methanol has proved to be successful in extracting numerous bioactive compounds including antibacterial compounds. The TLC-bioautography assay revealed the inhibitory action of two compounds which were identified as hydroxychavicol and eugenol. The $-caryophyllene however was totally inactive against all the tested bacterial species. In this study, the concentration of hydroxychavicol in extract was found to be 374.72±2.79 mg g-1, while eugenol was 49.67±0.16 mg g-1. CONCLUSION: Based on these findings, it could be concluded that hydroxychavicol and eugenol were the responsible compounds for the promising antibacterial activity of P. betle leaves methanolic extract. This inhibitory action has significantly correlated with the amount of the compounds in extract. Due to its potential, the extract of P. betle leaves or it compounds can be alternative source of potent natural antibacterial agents for aquaculture disease management.

Biofilm is associated with chronic streptococcal meningoencephalitis in fish.

Biofilms are aggregates of attached microbial organisms whose existence on tissues is often recognised as a mechanism for the establishment of most chronic diseases. Herein we investigated the ability of piscine Streptococcus agalactiae, an important aquatic pathogen, for adaptation to this sessile lifestyle in vitro and in the brain of a tilapia fish model. Piscine S. agalactiae exhibited a weak attachment to polystyrene plates and expressed a low biofilm phenotype under the study conditions. Furthermore, fluorescent in situ hybridization and confocal laser scanning microscopy revealed discrete aggregates of attached S. agalactiae within brain tissues and around meningeal surfaces. They were embedded in an exopolysaccharide containing matrix, intractable to inflammatory response and showed some level of resistance to penicillin despite proven susceptibility on sensitivity test. Intracellular bacterial aggregates were also observed, moreover, antibody mediated response was not demonstrated during infection. Nucleated erythrocytes appear to facilitate brain invasion possibly via the Trojan horse mechanism leading to a granulomatous inflammation. We have demonstrated that biofilm is associated with persistence of S. agalactiae and the development of chronic meningoencephalitis in fish.

Live recombinant Lactococcus lactis vaccine expressing aerolysin genes D1 and D4 for protection against Aeromonas hydrophila in tilapia (Oreochromis niloticus).

AIMS: To evaluate a live recombinant Lactococcus lactis vaccine expressing aerolysin genes D1 (Lac-D1ae) and/or D4 (Lac-D4ae) in protection against Aeromonas hydrophila in tilapia (Oreochromis niloticus). METHODS AND RESULTS: The polymerase chain reaction (PCR)-amplified 250- and 750-bp sequences coding for domains D1 and D4 of aerolysin were individually cloned into pNZ8048 and electrotransformed into L. lactis. The recombinant vaccine candidates were then either orally fed or injected intraperitoneally into tilapia. The development of antibodies in sampled fish compared to control groups implied that the recombinant epitopes expressed in L. lactis were able to elicit an immunogenic response in tilapia. Interestingly, the lower doses of both Lac-D1ae and Lac-D4ae gave higher antibody levels over the study period. Fish immunized with Lac-D1ae and Lac-D4ae together showed the highest level of protection, and the mortality was reduced significantly compared to control strains in both modes of vaccination. CONCLUSIONS: The recombinant L. lactis strain expressing D1 and D4 produced aerolysin-specific serum IgM in tilapia. Both D1 and D4 promoted 55-82% relative per cent survival (RPS) against Aeromonas infection through intraperitoneal injection, whereas the RPS following oral feeding of the vaccine was 70-100%. SIGNIFICANCE AND IMPACT OF THE STUDY: The D1 and D4 regions of the aerolysin protein have been successfully identified as immunogenic regions that can elicit antibody production in tilapia and protect against challenge with Aer. hydrophila. A promising oral vaccine using L. lactis harbouring the D1 and D4 regions has been developed to control Aer. hydrophila.

Radiographic assessment of gastric emptying and gastrointestinal transit time in hybrid tilapia (Oreochromis niloticus x O. mossambicus).

Hybrid tilapias (Oreochromis niloticus x O. mossambicus) were studied to determine gastric emptying and gastrointestinal transit time. The fish were divided into two groups. All fish were fasted for 12 h. The first experiment consisted of 11 fish fed with commercial food pellets and then administration of barium sulfate directly into the stomach using a blunt-end needle. Fish were then radiographed at different time intervals. The second experiment consisted of eight fish, which were given only barium sulfate after 12 h of fasting. In the first experiment, the stomach emptied completely, ranging from 4 to 15h postcontrast medium administration, whereas the gastrointestinal transit time ranged between 10 and 26 h. As for the second experiment, the contrast medium was still retained in the stomach in 50% of the fish after 24 h. The study did not proceed beyond 24 h as fish were considered stressed after this period of time. Thus, no data for the gastrointestinal transit time was obtained.

DNA fragmentation, an indicator of apoptosis, in cultured black tiger shrimp Penaeus monodon infected with white spot syndrome virus (WSSV).

Fifty black tiger shrimp Penaeus monodon from commercial cultivation ponds in Malaysia were examined by Tdt-mediated dUTP nick-end labeling (TUNEL) fluorescence assay and agarose gel electrophoresis of DNA extracts for evidence of DNA fragmentation as an indicator of apoptosis. From these specimens, 30 were grossly normal and 20 showed gross signs of white spot syndrome virus (WSSV) infection. Of the 30 grossly normal shrimp, 5 specimens were found to be positive for WSSV infection by normal histology and by nested polymerase chain reaction (PCR) analysis. All of the specimens showing gross signs of WSSV infection were positive for WSSV by normal histology, while 5 were positive by nested PCR only (indicating light infections) and 15 were positive by 1-step PCR (indicating heavy infections). Typical histological signs of WSSV infection included nuclear hypertrophy, chromatin condensation and margination. None of the 25 grossly normal shrimp negative for WSSV by 1-step PCR showed any signs of DNA fragmentation by TUNEL assay or agarose gel electrophoresis of DNA extracts. The 10 specimens that gave PCR-positive results for WSSV by nested PCR only (i.e., 5 grossly normal shrimp and 5 grossly positive for WSSV) gave mean counts of 16 +/- 8% TUNEL-positive cells, while the 25 specimens PCR positive by 1-step PCR gave mean counts of 40 +/- 7% TUNEL-positive cells. Thus, the number of TUNEL positive cells present in tissues increased with increasing severity of infection, as determined by gross signs of white spots on the cuticle, the number of intranuclear inclusions in histological sections, and results from single and nested PCR assays. DNA extracts of PCR-positive specimens tested by agarose gel electrophoresis showed indications of DNA fragmentation either as smears or as 200 bp ladders. Given that DNA fragmentation is generally considered to be a hallmark of apoptosis, the results suggested that apoptosis might be implicated in shrimp death caused by WSSV.

A new bacterial white spot syndrome (BWSS) in cultured tiger shrimp Penaeus monodon and its comparison with white spot syndrome (WSS) caused by virus.

This paper describes a new bacterial white spot syndrome (BWSS) in cultured tiger shrimp Penaeus monodon. The affected shrimp showed white spots similar to those caused by white spot syndrome virus (WSSV), but the shrimp remained active and grew normally without significant mortalities. The study revealed no evidence of WSSV infection using electron microscopy, histopathology and nested polymerase chain reaction. Electron microscopy indicated bacteria associated with white spot formation, and with degeneration and discoloration of the cuticle as a result of erosion of the epicuticle and underlying cuticular layers. Grossly the white spots in BWSS and WSS look similar but showed different profiles under wet mount microscopy. The bacterial white spots were lichen-like, having perforated centers unlike the melanized dots in WSSV-induced white spots. Bacteriological examination showed that the dominant isolate in the lesions was Bacillus subtilis. The occurrence of BWSS may be associated with the regular use of probiotics containing B. subtilis in shrimp ponds. The externally induced white spot lesions were localized at the integumental tissues, i.e., cuticle and epidermis, and connective tissues. Damage to the deeper tissues was limited. The BWS lesions are non-fatal in the absence of other complications and are usually shed through molting.

Histopathology and cytopathology of white spot syndrome virus (WSSV) in cultured Penaeus monodon from peninsular Malaysia with emphasis on pathogenesis and the mechanism of white spot formation.

Since 1994, white spot syndrome virus (WSSV) has been detected in cultured shrimp Penaeus monodon in Peninsular Malaysia. The gross signs, target organs and histo-cytopathology for the viral infection were studied and it was found to infect most organs and tissues including oocytes, but not hepatopancreatocytes and epithelial cells of the midgut, which were regarded as refractory tissues. Based on a time-sequence of ultrastructural cytopathology, 4 cytopathic profiles and 6 phases of viral morphogenesis were described. The virions were elliptical to short rods with trilamilar envelopes that measured 305 +/- 30 x 127 +/- 11 nm. Viral nucleosomes were often present singly in infected nuclei and were associated with the early stages of viral replication. The structure of WSSV pathognomonic white, cuticular lesions was examined at the microscopic and ultrastructural levels and the mechanism of their formation appeared to be related to the disruption of exudate transfer from epithelial cells to the cuticle via cuticular pore canals.

Relationship of scrotal circumference and testicular volume to age and body weight in the swamp buffalo (Bubalus bubalis).

Scrotal circumference (SC) and testicular volume (TV) were measured in 65 swamp buffalo bulls ranging in age from 7 to 60 months and weighing 130 kg to 560 kg. Ages and body weight (BW) were recorded for each male at the time of measurement to find out if they correlated with SC and TV. SC and TV increased linearly and correlated significantly with age and BW (SC vs age: r=0.74, p<0.01; SC vs BW: r=0.88, p<0.01; TV vs BW: r=0.82, p<0.01). SC measurements ranged from 15.1+/-1.1 cm to 24.0+/-0.4 cm for ages ranging from 10.0+/-0.6 to 48.5+/-6.3 months, revealing that testicular size in swamp buffaloes was very much smaller than domestic cattle. The SC norms distributed with age would be useful in the evaluation of swamp buffalo males for breeding soundness.