Severe Acute Respiratory Syndrome and Influenza

Primary Pandemic Prevention

Over the last few decades, hundreds of human pathogens have emerged at a rate unprecedented in human history. Emerged from where? Mostly from animals. The AIDS virus is blamed on the butchering of primates in the African bushmeat trade, we created mad cow disease when we turned cows into carnivores and cannibals, and SARS and COVID-19 have been traced back to the exotic wild animal trade. Our last pandemic, swine flu in 2009, arose not from some backwater wet market in Asia, however. It was largely made-in-the-USA on pig production operations in the United States. In this new Age of Emerging Diseases, there are now billions of animals overcrowded and intensively confined in filthy factory farms for viruses to incubate and mutate within. Today's industrial farming practices have given viruses billions more spins at pandemic roulette. How can we stop the emergence of pandemic viruses in the first place? Whenever possible, treat the cause. The largest and oldest association of public health professionals in the world, the American Public Health Association, has called for a moratorium on factory farming for nearly two decades. Indeed, factory farms are a public health menace. In addition to discontinuing the intensive confinement practices of animal agriculture, we should continue to research, develop, and invest in innovative plant-based and cultivated meat technologies to move away from raising billions of feathered and curly-tailed test tubes for viruses with pandemic potential to mutate within.

Regional disparities in Preventive measures of COVID-19 pandemic in China. A study from international students' prior knowledge, perception and vulnerabilities

The COVID-19 pandemic needs immediate solution before inflicting more devastation. So far, China has successfully controlled transmission of COVID-19 through implementing stringent preventive measures. In this study, we analyze the effectiveness of preventive measures taken in thirteen regions of China based on the feedback provided by 1135 international students studying in China. The study uses factor analysis combined with varimax rotation of variables. It was found that awareness raising and dispersing actionable knowledge regarding trust and adapting measures remained significantly important. Therefore, recognition of information gaps, improvements in the level of alertness, and development of preventive measures in each sector are imperative. The findings of this study revealed that trust, students' health, waste disposal, and the efforts of the Chinese government/international institute of education to prevent this pandemic were significantly and positively associated with preventive measures. The results showed that prior knowledge, global pandemics, and food and grocery purchases were firmly related to the preventive measures of COVID-19. Moreover, anxiety, transportation, and economic status were negatively related to the preventive measures. During this epidemic situation, international students suffered various types of mental stresses and anxiety, especially living in most affected regions of China. The study adopted a mixed (qualitative and quantitative) approach where the findings can act as a set of guidelines for governmental authorities in formulating, assisting in the preparation, instructing, and guiding policies to prevent and control the epidemic COVID-19 at national, local, and divisional levels.

Emerging Infectious Diseases: a Review

Purpose of Review

This review highlights some of the recent concerning emerging infectious diseases, a number of them specifically that the World Health Organization has categorized as priorities for research.

Recent Findings

Emerging and reemerging infectious diseases account for significant losses in not only human life, but also financially. There are a number of contributing factors, most commonly surrounding human behavior, that lead to disease emergence. Zoonoses are the most common type of infection, specifically from viral pathogens. The most recent emerging diseases in the USA are Emergomyces canadensis, the Heartland virus, and the Bourbon virus.

Summary

In addition to the aforementioned pathogens, the Severe Acute Respiratory Syndrome, Middle East Respiratory Syndrome, Nipah virus, New Delhi metallo-ß-lactamase-1 Enterobacteriaceae, Rift Valley Fever virus, and Crimean-Congo Hemorrhagic Fever virus are reviewed. These pathogens are very concerning with a high risk for potential epidemic, ultimately causing both significant mortality and financial costs. Research should be focused on monitoring, prevention, and treatment of these diseases.

Chinese travellers visiting friends and relatives--A review of infectious risks

Background

Travellers are potential vectors in the transmission of infectious diseases across international borders. Travellers visiting friends and relatives (VFR) have a particularly high risk of acquiring certain infections during travel. Chinese VFR travellers account for a substantial proportion of all travel in Western countries with high migrant populations.

Methods

A literature review was undertaken regarding major infectious disease risks for VFR travellers visiting China. This included an examination of the previous pandemics arising in China, the likelihood of future outbreaks in China from H5N1 and H7N9 avian influenza viruses, the potential role of travellers in disease transmission, and the special risks for VFR travellers.

Results

China has been the origin of several influenza pandemics in past few decades, and the origin of several emerging infectious diseases with pandemic potential, including SARS. Travel to and from China has the potential for global spread of emergent infectious diseases, as seen in the SARS outbreak in 2003. For VFR travellers, the risk of other infectious diseases may also be greater in China compared to their countries of migration, including hepatitis A and B, dengue fever, typhoid, and other diseases.

Conclusions

VFR travel to China may be associated with increased risk of acquiring a range of infectious diseases, and also poses a potential risk for importation of future pandemics to other countries. Chinese VFR travellers need to be cognisant of these risks and health professionals should consider educational interventions to minimise these risks.

Network analysis of global influenza spread

Although vaccines pose the best means of preventing influenza infection, strain selection and optimal implementation remain difficult due to antigenic drift and a lack of understanding global spread. Detecting viral movement by sequence analysis is complicated by skewed geographic and seasonal distributions in viral isolates. We propose a probabilistic method that accounts for sampling bias through spatiotemporal clustering and modeling regional and seasonal transmission as a binomial process. Analysis of H3N2 not only confirmed East-Southeast Asia as a source of new seasonal variants, but also increased the resolution of observed transmission to a country level. H1N1 data revealed similar viral spread from the tropics. Network analysis suggested China and Hong Kong as the origins of new seasonal H3N2 strains and the United States as a region where increased vaccination would maximally disrupt global spread of the virus. These techniques provide a promising methodology for the analysis of any seasonal virus, as well as for the continued surveillance of influenza.

Breeding Influenza: The Political Virology of Offshore Farming

  The geographic extent, xenospecificity, and clinical course of influenza A (H5N1), the bird flu strain, suggest the virus is an excellent candidate for a pandemic infection. Much attention has been paid to the virus's virology, pathogenesis and spread. In contrast, little effort has been aimed at identifying influenza's social origins. In this article, I review H5N1's phylogeographic properties, including mechanisms for its evolving virulence. The novel contribution here is the attempt to integrate these with the political economies of agribusiness and global finance. Particular effort is made to explain why H5N1 emerged in southern China in 1997. It appears the region's reservoir of near-human-specific recombinants was subjected to a phase change in opportunity structure brought about by China's newly liberalized economy. Influenza, 200 nm long, seems able to integrate selection pressures imposed by human production across continental distances, an integration any analysis of the virus should assimilate in turn.

Safety and immunogenicity of an MF59-adjuvanted subunit influenza vaccine in elderly Chinese subjects

BACKGROUND

The safety and immunogenicity of an MF59-adjuvanted subunit influenza vaccine (Sub/MF59; FLUAD, Novartis Vaccines) was evaluated among elderly Chinese subjects (> or = 60 years of age). After a preliminary Phase I, open-label study (n = 25) to assess safety 1-14 days post-vaccination, a comparative observer-blind, randomised, controlled clinical trial (n = 600) was performed to assess safety and immunogenicity versus a non-adjuvanted subunit influenza vaccine (Subunit; Agrippal, Novartis Vaccines). Subjects were randomised (2:1) to receive Sub/MF59 or Subunit.

RESULTS

Both vaccines were well tolerated, with no vaccine-related serious adverse events reported during the Phase I trial. During the observer-blind study, local and systemic reactions were generally similar for both vaccines 1-22 days post-vaccination; however, injection-site induration was more frequent among the Subunit group (P < 0.05), and mild pain at the injection site and fever were more frequent among Sub/MF59 recipients (P < or = 0.005). Both vaccines induced a significant (P < 0.001) increase in geometric mean titres (GMTs) for the three strains tested, versus baseline; GMTs against A/H1N1, A/H3N2 and B were significantly higher in the Sub/MF59 group (P = 0.034, P < 0.001 and P = 0.005, respectively). GMT ratios against A/H1N1, A/H3N2 and B were also significantly higher in the Sub/MF59 group (P = 0.038, P < 0.001 and P = 0.006, respectively). Similarly, the percentage of subjects achieving seroprotection or seroconversion on Day 22 was greater for Sub/MF59 recipients, reaching significance for A/H3N2 (P < 0.001).

CONCLUSION

MF59-adjuvanted subunit influenza vaccine is well tolerated by elderly Chinese subjects and induces a higher level of immunogenicity than a non-adjuvanted subunit influenza vaccine in this population that is at high risk of influenza-related complications.

CLINICAL TRIAL REGISTRY

http://www.clinicaltrials.gov, NCT00310648.

Anti-SARS drug screening by molecular docking

Starting from a collection of 1386 druggable compounds obtained from the 3D pharmacophore search, we performed a similarity search to narrow down the scope of docking studies. The template molecule is KZ7088 (Chou et al., 2003, Biochem Biophys Res Commun 308: 148-151). The MDL MACCS keys were used to fingerprint the molecules. The Tanimoto coefficient is taken as the metric to compare fingerprints. If the similarity threshold was 0.8, a set of 50 unique hits and 103 conformers were retrieved as a result of similarity search. The AutoDock 3.011 was used to carry out molecular docking of 50 ligands to their macromolecular protein receptors. Three compounds, i.e., C(28)H(34)O(4)N(7)Cl, C(21)H(36)O(5)N(6), and C(21)H(36)O(5)N(6), were found that may be promising candidates for further investigation. The main feature shared by these three potential inhibitors as well as the information of the involved side chains of SARS Cov Mpro may provide useful insights for the development of potent inhibitors against SARS enzyme.

Bacteriophage migration via nematode vectors: host-parasite-consumer interactions in laboratory microcosms

Pathogens vectored by nematodes pose serious agricultural, economic, and health threats; however, little is known of the ecological and evolutionary aspects of pathogen transmission by nematodes. Here we describe a novel model system with two trophic levels, bacteriophages and nematodes, each of which competes for bacteria. We demonstrate for the first time that nematodes are capable of transmitting phages between spatially distinct patches of bacteria. This model system has considerable advantages, including the ease of maintenance and manipulation at the laboratory bench, the ability to observe many generations in short periods, and the capacity to freeze evolved strains for later comparison to their ancestors. More generally, experimental studies of complex multispecies interactions, host-pathogen coevolution, disease dynamics, and the evolution of virulence may benefit from this model system because current models (e.g., chickens, mosquitoes, and malaria parasites) are costly to maintain, are difficult to manipulate, and require considerable space. Our initial explorations centered on independently assessing the impacts of nematode, bacterium, and phage population densities on virus migration between host patches. Our results indicated that virus transmission increases with worm density and host bacterial abundance; however, transmission decreases with initial phage abundance, perhaps because viruses eliminate available hosts before migration can occur. We discuss the microbial growth dynamics that underlie these results, suggest mechanistic explanations for nematode transmission of phages, and propose intriguing possibilities for future research.

An inhibitory effect of A20 on NF-kappaB activation in airway epithelium upon influenza virus infection

Influenza is a major disease in humans. The reemergence of avian influenza A viruses has indicated that hyperinflammatory responses are closely related to the severity of disease. Influenza virus infection induces nuclear transcription factor kappaB (NF-kappaB) activation. NF-kappaB and NF-kappaB-dependent gene products promote lung inflammation and injury. Therefore, it is important to investigate the means to attenuate NF-kappaB activation. A20 is a cytoplasmic zinc finger protein that inhibits NF-kappaB activity, However, little is known about the role of A20 in influenza virus infection. Here, we have examined the role of A20 in influenza virus infection-induced NF-kappaB promoter activation in human bronchial epithelial cells. The results showed that (1) A20 protein and mRNA are inducible and expressed in the lung from mice and human bronchial epithelial cells upon influenza virus infection; (2) NF-kappaB promoter activation was induced in bronchial epithelial cells upon influenza virus infection; and (3) overexpression by transient transfection of A20 attenuated NF-kappaB promoter activation in bronchial epithelial cells. These results indicate that A20 may function as a negative regulator of NF-kappaB-mediated lung inflammation and injury upon influenza virus infection, thereby protecting the host against inflammatory response to influenza virus infection.

Molecular modeling and chemical modification for finding peptide inhibitor against severe acute respiratory syndrome coronavirus main proteinase

Severe acute respiratory syndrome (SARS) is a respiratory disease caused by a newly found virus, called SARS coronavirus. In this study, the cleavage mechanism of the SARS coronavirus main proteinase (M^pro or 3CL^pro) on the octapeptide NH₂-AVLQ ↓ SGFR-COOH was investigated using molecular mechanics and quantum mechanics simulations based on the experimental structure of the proteinase. It has been observed that the catalytic dyad (His-41/Cys-145) site between domains I and II attracts the π electron density from the peptide bond Gln–Ser, increasing the positive charge on C(CO) of Gln and the negative charge on N(NH) of Ser, so as to weaken the Gln–Ser peptide bond. The catalytic functional group is the imidazole group of His-41 and the S in Cys-145. N_δ1 on the imidazole ring plays the acid–base catalytic role. Based on the “distorted key theory” [K.C. Chou, Anal. Biochem. 233 (1996) 1–14], the possibility to convert the octapeptide to a competent inhibitor has been studied. It has been found that the chemical bond between Gln and Ser will become much stronger and no longer cleavable by the SARS enzyme after either changing the carbonyl group CO of Gln to CH₂ or CF₂ or changing the NH of Ser to CH₂ or CF₂. The octapeptide thus modified might become an effective inhibitor or a potential drug candidate against SARS.

Polyprotein cleavage mechanism of SARS CoV Mpro and chemical modification of the octapeptide

The cleavage mechanism of severe acute respiratory syndrome (SARS) coronavirus main proteinase (M(pro) or 3CL(pro)) for the octapeptide AVLQSGFR is studied using molecular mechanics (MM) and quantum mechanics (QM). The catalytic dyad His-41 and Cys-145 in the active pocket between domain I and II seem to polarize the pi-electron density of the peptide bond between Gln and Ser in the octapeptide, leading to an increase of positive charge on C(CO) of Gln and negative charge on N(NH) of Ser. The possibility of enhancing the chemical bond between Gln and Ser based on the "distorted key" theory [Anal. Biochem. 233 (1996) 1] is examined. The scissile peptide bond between Gln and Ser is found to be solidified through "hybrid peptide bond" by changing the carbonyl group CO of Gln to CH(2) or CF(2). This leads to a break of the pi-bond system for the peptide bond, making the octapeptide (AVLQSGFR) a "distorted key" and a potential starting system for the design of anti SARS drugs.