Respiratory Viral Infections (RSV, Rhino, Corona, Influenza) PDF

RSV: A Severe Respiratory Threat An overview of Respiratory Syncytial Virus (RSV), a highly contagious and potentially severe respiratory illness affecting infants and older adults.  Introduction to RSV RSV is a highly contagious respiratory...

RSV: A Severe Respiratory Threat An overview of Respiratory Syncytial Virus (RSV), a highly contagious and potentially severe respiratory illness affecting infants and older adults.  Introduction to RSV RSV is a highly contagious respiratory RSV infections are a significant public High-risk groups for severe RSV virus health burden infections It is the leading cause of lower respiratory They account for a substantial number of Infants, young children, older adults, and tract infections in infants and young children. hospitalizations and medical costs annually individuals with compromised immune systems worldwide. or chronic medical conditions are at higher risk. Understanding the impact of RSV on public health is crucial for developing effective prevention and management strategies.  Seasonal Patterns November - March April Late Fall Peak RSV season in RSV infections typically RSV transmission most areas decline accelerates nationwide October - November Summer Early Spring Low RSV activity during RSV cases dwindle RSV cases begin to rise warm months after winter surge in fall  RSV Properties Classification Replication RSV belongs to the family Paramyxoviridae, RSV replicates in the cytoplasm of host cells. The genus Orthopneumovirus, classified as a viral RNA is transcribed into mRNAs, which are negative-sense, single-stranded RNA virus. It is then translated into viral proteins. New viral further categorized into two major groups, RSV- genomes are synthesized and packaged into A and RSV-B, based on genetic and antigenic progeny virions, which are subsequently differences. released from the infected cell through budding. Structure RSV is an enveloped virus with a helical nucleocapsid. Its genome encodes for 11 viral proteins, including the fusion (F) and attachment (G) glycoproteins, which play crucial roles in viral entry and pathogenesis. It is pleomorphic in shape, appearing as spherical or filamentous particles under electron microscopy.  RSV Pathogenesis o The host immune response to RSV infection plays a critical role in disease severity, with excessive inflammation contributing to respiratory symptoms and lung damage. o In severe cases, RSV infection can lead to bronchiolitis, pneumonia, and respiratory failure, particularly in infants, young children, and older adults.  Transmission Pathways Droplet Contact Aerosol Contaminated Close Personal Transmission Transmission Transmission Fomites Contact  High-Risk Groups 1 Premature infants born before 29 weeks of gestation 2 Children under 2 years old with chronic lung disease or congenital heart disease 3 Adults aged 65 years and older with weakened immune systems 4 Individuals with chronic conditions such as asthma, COPD, or diabetes  Clinical Manifestations Percentage of RSV cases requiring hospitalization by age group 26% 20% 14% 15% Infants under 6 months Infants 6-11 months Children 1-2 years Adults 65 and older  Clinical Manifestations o In infants, symptoms may include cough, wheezing, difficulty breathing, fever, and poor feeding. o In adults and older children, RSV infections often present as mild cold symptoms but can progress to more severe respiratory illness, especially in individuals with underlying health conditions.  Diagnosis and Testing Diagnosing respiratory syncytial virus (RSV) typically involves analyzing patient symptoms and conducting laboratory tests on respiratory samples. Common methods include rapid antigen testing, molecular testing like RT-PCR, and virus culture. Chest X-rays may be used to evaluate the extent of lung involvement in severe cases.  Management and Treatment Mild Cases Severe Cases: Supportive Severe Cases: Antiviral Care Treatment Monoclonal Antibody Treatment Preventive Measures  Prevention Strategies Handwashing and Hygiene, Respiratory Etiquette, and Avoiding Close Contact Potential Maternal RSV Vaccine Monoclonal Antibody Prophylaxis Development of Pediatric RSV Vaccine Rhinovirus: A Common Cold Culprit  Introduction Highly contagious virus Causes common cold symptoms Diverse strains Rhinovirus is a highly contagious virus that Rhinovirus is a leading cause of the common There are over 100 different strains of rhinovirus, spreads easily through coughing, sneezing, or cold, responsible for a significant number of making it challenging to develop effective touching contaminated surfaces. respiratory infections worldwide. vaccines or treatments. Rhinovirus is a ubiquitous and highly contagious respiratory virus that causes the common cold, with diverse strains posing ongoing challenges in prevention and treatment.  Properties of Rhinovirus Virology Receptor Binding Genome Replication Structure Transmission Serotypes Clinical Manifestations  Virology Classification of Rhinovirus Genome Structure Viral Replication Cycle Rhinovirus belongs to the Picornaviridae The rhinovirus genome is a single-stranded The rhinovirus replication cycle begins with family, specifically the Enterovirus genus. It is RNA molecule of approximately 7,200 the attachment of the virus to specific cell a non-enveloped, positive-sense single- nucleotides. It contains a single open reading surface receptors, followed by entry into the stranded RNA virus. frame that encodes a polyprotein, which is host cell. Once inside, the viral genome is subsequently cleaved into structural and non- released, and viral proteins are synthesized. structural proteins. New viral particles are then assembled and released from the host cell.  Epidemiology 1 3 5 Rhinovirus prevalence Molecular epidemiology Asymptomatic carriers peaks during fall and reveals multiple co- contribute to spring seasons. circulating strains. community spread. 2 4 6 Transmission rates surge Colder temperatures and Surveillance data in closed settings like low humidity favor virus tracks strain diversity schools and offices. stability. and evolution.  Pathogenesis Rhinovirus, a small and highly contagious virus, employs a sophisticated mechanism to invade and replicate within human respiratory cells, triggering a cascade of immune responses that ultimately manifest as the familiar symptoms of the common cold. Its pathogenesis involves a complex interplay between viral entry, replication strategies, and the body's defensive mechanisms.  Clinical Presentation Runny or stuffy nose Fever Rhinovirus infections often cause nasal congestion and Mild to moderate fever is possible, especially in more rhinorrhea. severe cases. Sore throat Headache and body aches Pharyngitis or throat irritation is a common symptom. Headache, muscle aches, and fatigue are often reported. Cough Dry, persistent cough may accompany rhinovirus infections.  Immunity Immunity to rhinovirus is serotype-specific, meaning that infection with one serotype does not confer immunity to other serotypes.  Diagnosis Polymerase Chain Reaction (PCR) Viral Culture Serology (Antibody Testing) Clinical Symptoms Implications for Clinical Practice  Treatment and Management Adequate Fluid Intake Rest and Symptom Relief Medications Antibiotics for Secondary Bacterial Infections  Prevention Practice frequent and thorough handwashing with soap 1 and water or use an alcohol-based hand sanitizer 2 Cover coughs and sneezes with a tissue or the inside of the elbow to prevent respiratory droplet transmission 3 Avoid close contact with individuals exhibiting cold symptoms 4 Explore potential vaccine development targeting common rhinovirus strains Coronaviruses: An Overview An exploration of the nature, transmission, and impact of the coronavirus family, including the COVID-19 pandemic.  Introduction to Coronaviruses Coronaviruses are a family of They are enveloped viruses Positive-sense single- Belonging to the viruses stranded RNA Coronaviridae family They are a diverse group of viruses The genetic material is The viral genome consists of a Coronaviruses belong to the that can infect various animal encapsulated within a lipid single-stranded RNA molecule Coronaviridae family, which is species, including humans. membrane envelope, which with positive polarity, allowing further classified into four facilitates entry into host cells. direct translation into proteins. genera: Alphacoronavirus, Betacoronavirus, Gammacoronavirus, and Deltacoronavirus. Coronaviruses are a diverse group of enveloped RNA viruses that can infect various animal species, including humans, causing a range of illnesses from mild respiratory infections to severe diseases.  Classification of Coronaviruses Alphacoronavirus Gammacoronavirus A genus of coronaviruses that includes human A genus of coronaviruses that primarily infects birds, but coronaviruses like HCoV-229E and HCoV-NL63, as well as also includes some mammalian coronaviruses like the some animal coronaviruses like the porcine porcine respiratory coronavirus and the mink transmissible gastroenteritis virus (TGEV). coronavirus. Betacoronavirus Deltacoronavirus A genus of coronaviruses that includes the severe acute A genus of coronaviruses that mainly infects birds and respiratory syndrome coronavirus (SARS-CoV), the mammals, including the porcine deltacoronavirus and Middle East respiratory syndrome coronavirus (MERS- some avian deltacoronaviruses. CoV), and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes COVID-19. It also includes some other human and animal coronaviruses.  Timeline of Major Coronavirus Outbreaks 2003 2019 2021 SARS-CoV outbreak SARS-CoV-2 outbreak COVID-19 vaccines originating in China's leading to COVID-19 become widely available, Guangdong province. pandemic begins in rollout begins globally. Wuhan, China. 2012 2020 2022 MERS-CoV outbreak WHO declares COVID-19 Omicron variant drives first reported in Saudi a global pandemic. new wave of COVID-19 Arabia. cases worldwide. Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) o Identified in 2003, SARS-CoV caused an outbreak of severe acute respiratory syndrome (SARS) with high mortality rates. o Transmission primarily occurred through close contact with infected individuals. Middle East Respiratory Syndrome Coronavirus (MERS-CoV) o Identified in 2012, MERS-CoV caused outbreaks of Middle East respiratory syndrome (MERS), characterized by severe respiratory illness. o Transmission primarily occurred through contact with camels or consumption of camel products in affected regions. Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) o Identified in December 2019, SARS-CoV-2 is the causative agent of the coronavirus disease 2019 (COVID-19) pandemic. o It is highly transmissible and has caused millions of infections worldwide, leading to significant morbidity and mortality. Virology of SARS-CoV-2  Transmission and Clinical Presentation Transmission Asymptomatic Infection Mild Symptoms Severe Illness High-Risk Groups Clinical Variability  Diagnosis and Management Observe and document typical Confirm diagnosis through RT- symptoms such as fever, cough, Gather information about PCR (Reverse Transcription Provide supportive treatment shortness of breath, and loss of potential exposure, travel Polymerase Chain Reaction) such as oxygen therapy, fluid taste or smell. history, and contact tracing to testing for viral RNA detection. management, and monitoring assess risk. for complications. Epidemiological History Clinical Symptoms Laboratory Testing Supportive Care Monoclonal Antibodies Antiviral Medications Corticosteroids Consider the use of approved Administer corticosteroids like Explore the use of monoclonal antiviral drugs like remdesivir or dexamethasone in severe cases antibody therapies like molnupiravir in eligible cases. to reduce inflammation and bamlanivimab or improve outcomes. casirivimab/imdevimab in high- risk patients.  Prevention and Control Strategies Vaccination Physical Distancing Get vaccinated against COVID-19 to build immunity and Maintain a safe distance of at least 6 feet from others reduce severe illness. outside your household to reduce exposure. Wear Face Masks Avoid Large Gatherings Wear a properly fitted face mask in indoor public spaces Avoid crowded events, parties, and gatherings where and crowded outdoor areas to prevent transmission. distancing is difficult to prevent viral spread. Hand Hygiene Follow Public Health Guidelines Wash hands frequently with soap and water or use an Stay informed and adhere to local public health alcohol-based sanitizer to kill viruses. guidelines and regulations to protect yourself and others. Influenza Viruses  Introduction to Influenza Viruses Orthomyxoviridae family Influenza B viruses They belong to the Orthomyxoviridae family of viruses, Influenza B viruses primarily infect humans and can which is known for their segmented RNA genome. cause seasonal outbreaks, but they do not undergo significant antigenic shifts like influenza A viruses. Types of influenza viruses Influenza viruses are categorized into types A, B, C, and Influenza C and D viruses D, each with distinct characteristics and host ranges. Influenza C viruses cause mild illness in humans, while influenza D viruses primarily infect cattle and other livestock but have been detected in humans as well. Influenza A viruses Influenza A viruses are the most widespread and cause seasonal epidemics and occasional pandemics in humans, as well as infecting various animal species.  Influenza A Viruses Broadest host range Cause seasonal epidemics Occasional pandemics Influenza A viruses can infect humans, birds, These viruses undergo frequent genetic Major genetic shifts can result in new pigs, and other mammals. mutations, leading to seasonal flu outbreaks. pandemic strains that spread rapidly worldwide. Influenza A viruses pose significant public health challenges due to their ability to cross species barriers, cause recurring seasonal epidemics, and potentially trigger devastating pandemics.  Influenza B and C Viruses Influenza B primarily infects humans Influenza C causes mild respiratory It is responsible for seasonal flu outbreaks, causing illness widespread illness and hospitalizations. It generally leads to mild and self-limiting respiratory infections, rarely causing severe complications. While Influenza B poses a significant public health concern due to its seasonal nature and potential severity, Influenza C typically results in milder respiratory illnesses.  Comparison of Influenza Types On a scale of 1-100, representing the broadest range and highest severity 80 50 30 20 Influenza A Influenza B Influenza C Influenza D  Influenza Virus Timeline 1918 1968 1957 2009  Viral Structure Segmented negative-sense Envelope with HA and NA HA facilitates viral entry NA aids in viral release from RNA genome surface glycoproteins into host cells host cells The unique structure of the influenza virus, with its segmented negative-sense RNA genome and envelope with HA and NA proteins, enables its entry into host cells, replication, and release, contributing to its pathogenicity and ability to cause flu outbreaks. Genetic Reassortment  Clinical Manifestations Fever Muscle aches High body temperature, typically above 100.4°F (38°C), Widespread muscle pain and body aches, commonly caused by the immune system's response to the affecting the back, arms, and legs, caused by the body's influenza virus. immune response. Cough Fatigue Dry, persistent cough caused by inflammation and Overwhelming tiredness and lack of energy, often irritation of the respiratory tract due to the virus. accompanied by weakness and lethargy. Sore throat Severe cases Painful inflammation and swelling of the throat and In severe cases, influenza can progress to pneumonia, tonsils, often accompanied by difficulty swallowing. respiratory failure, and potentially lead to death, especially in high-risk groups.  High-risk Groups Elderly Pregnant women Individuals over 65 years old have weakened immune Pregnancy changes the immune system, heart, and systems, making them more vulnerable to severe lungs, increasing the risk of severe illness from influenza complications. influenza for both the mother and the unborn baby. Young children Individuals with underlying health conditions Children under 5 years old, especially those younger than 2, have immature immune systems and are at higher risk of influenza-related complications. Those with chronic conditions like asthma, diabetes, or heart disease have weakened immune systems, making them more susceptible to influenza complications. These high-risk groups require extra precautions, such as annual influenza vaccinations and prompt medical attention if influenza symptoms develop, to reduce the risk of severe illness or complications.  Prevention and Control Vaccination Antiviral Medications