Respiratory tract infections: emerging viral pathogens

Development of an Antiviral Ion-Activated In Situ Gel Containing 18β-Glycyrrhetinic Acid: A Promising Alternative against Respiratory Syncytial Virus

The human respiratory syncytial virus (hRSV) is a major cause of serious lower respiratory infections and poses a considerable risk to public health globally. Only a few treatments are currently used to treat RSV infections, and there is no RSV vaccination. Therefore, the need for clinically applicable, affordable, and safe RSV prevention and treatment solutions is urgent. In this study, an ion-activated in situ gelling formulation containing the broad-spectrum antiviral 18β-glycyrrhetinic acid (GA) was developed for its antiviral effect on RSV. In this context, pH, mechanical characteristics, ex vivo mucoadhesive strength, in vitro drug release pattern, sprayability, drug content, and stability were all examined. Rheological characteristics were also tested using in vitro gelation capacity and rheological synergism tests. Finally, the cytotoxic and antiviral activities of the optimized in situ gelling formulation on RSV cultured in the human laryngeal epidermoid carcinoma (HEp-2) cell line were evaluated. In conclusion, the optimized formulation prepared with a combination of 0.5% w/w gellan gum and 0.5% w/w sodium carboxymethylcellulose demonstrated good gelation capacity and sprayability (weight deviation between the first day of the experiment (T0) and the last day of the experiment (T14) was 0.34%), desired rheological synergism (mucoadhesive force (Fb): 9.53 Pa), mechanical characteristics (adhesiveness: 0.300 ± 0.05 mJ), ex vivo bioadhesion force (19.67 ± 1.90 g), drug content uniformity (RSD%: 0.494), and sustained drug release over a period of 6 h (24.56% ± 0.49). The optimized formulation demonstrated strong anti-hRSV activity (simultaneous half maximal effective concentration (EC50) = 0.05 µg/mL; selectivity index (SI) = 306; pre-infection EC50 = 0.154 µg/mL; SI = 100), which was significantly higher than that of ribavirin (EC50 = 4.189 µg/mL; SI = 28) used as a positive control against hRSV, according to the results of the antiviral activity test. In conclusion, this study showed that nasal in situ gelling spray can prevent viral infection and replication by directly inhibiting viral entry or modulating viral replication.

Evolutionary study of COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as an emerging coronavirus: Phylogenetic analysis and literature review

Since emerging coronaviruses have always become a human health concern globally especially severe acute respiratory syndrome coronavirus 2 (SARS-CoV) and Middle East respiratory syndrome coronavirus and a novel coronavirus was introduced in Wuhan, China, in December 2019 (called SARS-CoV-2), many researchers focused on its epidemics, virological and clinical features. SARS-CoV-2 is classified as Betacoronaviruses genus and Sarbecovirus subgenus (lineage B). The virus shows a great similarity with SARS-CoV and bat SARS-like coronaviruses. In this study, we evaluate SARS-CoV-2 virus phylogeny and evolution by using current virus and related sequences.

Overview of Current Therapeutics and Novel Candidates Against Influenza, Respiratory Syncytial Virus, and Middle East Respiratory Syndrome Coronavirus Infections

Emergence and re-emergence of respiratory virus infections represent a significant threat to global public health, as they occur seasonally and less frequently (such as in the case of influenza virus) as pandemic infections. Some of these viruses have been in the human population for centuries and others had recently emerged as a public health problem. Influenza viruses have been affecting the human population for a long time now; however, their ability to rapidly evolve through antigenic drift and antigenic shift causes the emergence of new strains. A recent example of these events is the avian-origin H7N9 influenza virus outbreak currently undergoing in China. Human H7N9 influenza viruses are resistant to amantadines and some strains are also resistant to neuraminidase inhibitors greatly limiting the options for treatment. Respiratory syncytial virus (RSV) may cause a lower respiratory tract infection characterized by bronchiolitis and pneumonia mainly in children and the elderly. Infection with RSV can cause severe disease and even death, imposing a severe burden for pediatric and geriatric health systems worldwide. Treatment for RSV is mainly supportive since the only approved therapy, a monoclonal antibody, is recommended for prophylactic use in high-risk patients. The Middle East respiratory syndrome coronavirus (MERS-CoV) is a newly emerging respiratory virus. The virus was first recognized in 2012 and it is associated with a lower respiratory tract disease that is more severe in patients with comorbidities. No licensed vaccines or antivirals have been yet approved for the treatment of MERS-CoV in humans. It is clear that the discovery and development of novel antivirals that can be used alone or in combination with existing therapies to treat these important respiratory viral infections are critical. In this review, we will describe some of the novel therapeutics currently under development for the treatment of these infections.

Multiple Viral Infection Detected from Influenza-Like Illness Cases in Indonesia

Influenza is one of the common etiologies of the upper respiratory tract infection (URTI). However, influenza virus only contributes about 20 percent of influenza-like illness patients. The aim of the study is to investigate the other viral etiologies from ILI cases in Indonesia. Of the 334 samples, 266 samples (78%) were positive at least for one virus, including 107 (42%) cases of multiple infections. Influenza virus is the most detected virus. The most frequent combination of viruses identified was adenovirus and human rhinovirus. This recent study demonstrated high detection rate of several respiratory viruses from ILI cases in Indonesia. Further studies to determine the relationship between viruses and clinical features are needed to improve respiratory disease control program.

A framework for the non-antibiotic management of upper respiratory tract infections: towards a global change in antibiotic resistance

Antibiotic resistance has become a critical health issue on a global scale, with much of the problem resulting from inappropriate use of antibiotics in primary care. To change this practice, the global respiratory infection partnership has formulated a pentagonal (five P) framework for the non-antibiotic management of upper respiratory tract infections (URTIs) - one of the most common conditions in primary care for which antibiotics are prescribed. The framework presents the rationale for focusing on URTIs to promote antibiotic stewardship in primary care and elaborates on five key areas to focus on to bring about change: policy, prevention, prescribers, pharmacy and patients. The ultimate aim is to adopt a patient-centred symptomatic management strategy using a flexible framework that can be adapted across countries to create a consistent global approach to change behaviour.

Sore throat: effective communication delivers improved diagnosis, enhanced self-care and more rational use of antibiotics

The majority of throat infections are of viral origin and resolve without antibiotic treatment. Despite this, antibiotic use for sore throat infections remains high, partly because it is difficult to determine when antibiotics may be useful, on the basis of physical findings alone. Antibiotics may be beneficial in bacterial throat infections under certain clinical and epidemiological circumstances; however, even many of those infections in which bacteria play a role do resolve just as quickly without antibiotics. Furthermore, non-medical factors such as patient expectations and patient pressure are also important drivers of antibiotic use. To address these issues, a behavioural change is required that can be facilitated by improved communication between primary healthcare providers and patients. In this article, we provide doctors, nurses and pharmacy staff, working in primary care or in the community, with a structured approach to sore throat management, with the aim of educating and empowering patients to self-manage their condition. The first component of this approach involves identifying and addressing patients' expectations and concerns with regard to their sore throat and eliciting their opinion on antibiotics. The second part is dedicated to a pragmatic assessment of the severity of the condition, with attention to red-flag symptoms and risk factors for serious complications. Rather than just focusing on the cause (bacterial or viral) of the upper respiratory tract infections as a rationale for antibiotic use, healthcare providers should instead consider the severity of the patient's condition and whether they are at high risk of complications. The third part involves counselling patients on effective self-management options and providing information on the expected clinical course. Such a structured approach to sore throat management, using empathetic, non-paternalistic language, combined with written patient information, will help to drive patient confidence in self-care and encourage them to accept the self-limiting character of the illness - important steps towards improving antibiotic stewardship in acute throat infections.