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Questions and Answers
Which of the following viruses is NOT classified as an RNA virus based on the provided information?
Which of the following viruses is NOT classified as an RNA virus based on the provided information?
Which of the following viruses is specifically associated with the common cold, according to the content provided?
Which of the following viruses is specifically associated with the common cold, according to the content provided?
Based on the information provided, which of these is NOT mentioned as a symptom of common cold?
Based on the information provided, which of these is NOT mentioned as a symptom of common cold?
According to the provided content, which of these viruses is NOT associated with respiratory illness?
According to the provided content, which of these viruses is NOT associated with respiratory illness?
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Based on the information provided, which of these viruses is specifically classified as an emerging virus?
Based on the information provided, which of these viruses is specifically classified as an emerging virus?
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Which of these viruses is more likely to cause an excessive inflammatory response that can lead to respiratory failure?
Which of these viruses is more likely to cause an excessive inflammatory response that can lead to respiratory failure?
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Which virus primarily affects the upper and lower respiratory system?
Which virus primarily affects the upper and lower respiratory system?
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What is the vaccine available for adults over 60 in Canada?
What is the vaccine available for adults over 60 in Canada?
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What is the main cause of fluctuations in influenza prevalence?
What is the main cause of fluctuations in influenza prevalence?
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Which of these viruses is known to cause an increased risk of bacterial infections in the infected individual?
Which of these viruses is known to cause an increased risk of bacterial infections in the infected individual?
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Which of these viruses typically has a shorter recovery period?
Which of these viruses typically has a shorter recovery period?
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Which of these viruses is associated with inflammation in the airways?
Which of these viruses is associated with inflammation in the airways?
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Which of these viruses is known to progress to bronchitis or pneumonia?
Which of these viruses is known to progress to bronchitis or pneumonia?
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Which of these viruses has a vaccine available that is specifically targeted at adults over 60 years old?
Which of these viruses has a vaccine available that is specifically targeted at adults over 60 years old?
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Which of these viruses has a segmented genome?
Which of these viruses has a segmented genome?
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Which of these is the most likely to be a common symptom of a coronavirus infection, according to the information provided?
Which of these is the most likely to be a common symptom of a coronavirus infection, according to the information provided?
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Based on the characteristics of coronaviruses described in the text, which statement BEST describes their structure?
Based on the characteristics of coronaviruses described in the text, which statement BEST describes their structure?
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What is the MAIN reason inhalers are being prescribed more frequently for coronavirus-related symptoms?
What is the MAIN reason inhalers are being prescribed more frequently for coronavirus-related symptoms?
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Based on the timeline provided, which statement about the spread of coronaviruses is TRUE?
Based on the timeline provided, which statement about the spread of coronaviruses is TRUE?
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Which of the following is NOT a type of infection caused by coronaviruses, according to the information provided?
Which of the following is NOT a type of infection caused by coronaviruses, according to the information provided?
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Study Notes
RNA Viruses
- RNA viruses are a diverse group of pathogens.
- Specific examples of RNA viruses include coronaviruses (OC43, 229E, IBV), enterovirus, HAV, HCV, HEV, HIV, HTLV, and human metapneumovirus.
- Included are also influenza A and B, Measles, MERS, Mumps, Norovirus, Parainfluenza, Polio, Rhinoviruses, RSV, Rubella, SARS, SARS-CoV-2, and Rotavirus.
Learning Objectives
- The learning objectives are to describe the symptoms, diagnosis, and treatment of common RNA viruses.
Common Cold Symptoms
- Common cold symptoms include sneezing, stuffy nose, runny nose, sore throat, coughing, post-nasal drip, watery eyes, fever (rare), and chills (rare).
- Physicians should monitor symptoms and their severity, and prescribe inhalers if necessary.
- Breathing and temperature monitoring, along with careful observation for rashes, are critical in these scenarios.
Coronaviruses Background
- Coronaviruses are a family of enveloped, positive-sense, single-stranded RNA viruses.
- They have the largest genomes of all RNA viruses, approximately 30 kilobases (kb).
- Coronaviruses infect humans, other mammals, some birds, livestock, and pets.
- They account for 10-15% of upper respiratory tract infections.
Nidovirales Coronaviridae
- Nidoviruses are named for the nested subgenomic mRNAs generated during infection.
- Coronaviruses are enveloped viruses, ranging in size from 100 to 150 nanometers (nm).
- Coronaviruses contain RNA genomes.
Types of Infections from Coronaviruses
- Coronaviruses can infect the respiratory system (human OC43, 229E, avian IBV), lead to brain infections (neurotropic MHV, demyelinating), liver infections (MHV), or gastrointestinal infections (procine TGEV, avian IBV, MHV).
Human Coronaviruses: Timeline
- The common cold coronaviruses OC43, and 229E have been circulating since the 1980s.
- SARS-CoV emerged in 2002, MERS-CoV in 2012, and SARS-CoV-2 (COVID-19) emerged in 2019.
- Data related to deaths and infection fatality rates are provided for SARS-CoV, MERS-CoV, and SARS-CoV-2.
- Influenza infection rates are also included as a point of comparison.
Human Metapneumovirus
- Human metapneumovirus can cause upper and lower respiratory illnesses, affecting people of all ages but particularly young children and older adults.
- Symptoms include cough, fever, nasal congestion, and they can progress to bronchitis or pneumonia.
- There is no specific treatment, and no vaccine is currently available.
Respiratory Syncytial Virus (RSV)
- RSV usually causes mild cold-like symptoms.
- Most people recover within 1-2 weeks, but RSV can be serious in infants and older adults due to inflammation and complications arising in the airways.
- Symptoms include a runny nose, decreased appetite, coughing, sneezing, fever, and wheezing.
- Almost all children have been exposed to RSV by their second birthday.
- A vaccine (mRESVIA, mRNA) is now available for adults older than 60.
- No specific treatment is available.
Influenza
- 75-95% of influenza cases are influenza A, and the remaining 5-25% are influenza B.
- The virus affects the nose, throat, and lungs.
- Influenza can cause mild to severe illness.
- Symptoms include fever (though not everyone experiences it), cough, sore throat, runny/stuffy nose, muscle aches, headache, fatigue, and potentially vomiting and diarrhea.
- Flu patients are more susceptible to bacterial infections.
- Cytokine storm syndrome, caused by an excessive inflammatory response, can complicate respiratory failure and lead to systemic organ failure.
Influenza (Orthomyxoviridae)
- Orthomyxoviridae have segmented genomes that allow for reassortment, generating strains with different HA/NA combinations.
- This contributes to the prevalence of influenza and impacts vaccine design and effectiveness from year to year.
Influenza (Oseltamivir)
- Oseltamivir (Tamiflu) is a neuraminidase inhibitor used to treat influenza A and B.
- It prevents the production of new virus particles.
- Its use is less common now due to the development of resistance.
Rotavirus
- Rotavirus is a double-stranded RNA virus of the Reoviridae family.
- It causes symptoms like watery diarrhea, vomiting, fever, and abdominal pain.
- There is no virus-specific cure.
- A 2-dose vaccine for Rotavirus is available.
Norovirus
- Norovirus is a single-stranded RNA virus of the Caliciviridae family.
- Its symptoms include diarrhea, vomiting, nausea, and stomach pain.
- There is no specific treatment or vaccine available.
Measles Virus
- Measles symptoms usually appear 10–14 days post-exposure.
- Symptoms include fever, cough, coryza (common cold-like symptoms), conjunctivitis, and a characteristic rash.
- Diagnosis is confirmed through presence of measles virus antibodies or viral RNA in respiratory samples.
Measles Complications
- Measles can complicate with various outcomes like diarrhea, pneumonia, bronchitis, and rarely, subacute sclerosing panencephalitis, and corneal ulceration.
Measles Treatment
- There's no specific treatment for measles.
- Treatment focuses on alleviating symptoms, including the use of ibuprofen, airway dilators (if necessary), and Vitamin A supplementation to reduce risk of blindness.
Human Immunodeficiency Virus (HIV)
- HIV is the etiological agent responsible for AIDS.
- AIDS was discovered in 1981.
- HIV itself was discovered in 1984.
- Globally, approximately 40 million people are living with HIV, with ~50,000 cases in Canada.
- No vaccine is available.
- There are approximately 30 drugs currently used, targeting reverse transcriptase, protease, entry, and integrase.
Acute HIV Infection
- Primary HIV infection is often not diagnosed except in high-risk individuals undergoing frequent testing.
- Late diagnosis is frequent, especially in rural areas, primarily due to the lack of symptoms.
- Even for those at high risk, stigma and a lack of trust/confidentiality can decrease testing rates.
Chronic HIV Infection
- Symptoms of chronic HIV infection/AIDS include nausea, vomiting, persistent diarrhea, rapid weight loss, rashes, sores, lesions, and persistent infections including neurological symptoms like memory loss and confusion.
Course of HIV Disease
- The course of HIV disease is visually depicted with a graph showing CD4+ T-cell counts, viral load, and anti-HIV antibody levels over time.
HIV Therapy
- Treatment approaches including nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), binding and fusion inhibitors, integrase inhibitors, and latency-reversing agents are employed.
HIV Therapy Response
- A successful response to therapy shows a decrease in viral load, an increase in CD4+ T cells, and the eventual resolution of symptoms.
HIV in 2019
- HIV is now considered a chronic, manageable condition, particularly with access to therapy.
- Despite therapy, infected individuals still experience mortality from causes similar to those in the general uninfected population.
- Elite controllers maintain low viral loads for years without antiretroviral therapy (ART).
Hepatitis C Virus (HCV)
- 70-85% of untreated HCV infections become chronic.
- Some individuals recover from the infection.
- 15-20% develop hepatocellular carcinoma.
Statistics For HCV
- Globally, approximately 71 million people are infected with HCV.
- In Canada, about 270,000 individuals are infected with HCV (this is approximately 0.8% of the population, or 2-4 per 100,000).
- Approximately 3,200 to 5,000 new HCV cases are diagnosed annually in Canada.
Routes of HCV Infection
- The most common route of infection is through the injection of contaminated drugs (60%).
- Other routes include unknown factors (10%), other healthcare settings (5%), transfusion (10%), and sexual contact (15%).
Chronic Hepatitis C
- Common symptoms of chronic HCV infection include fatigue, muscle aches, loss of appetite, weakness, and weight loss.
- Other complications include blood clotting problems and liver-specific issues such as cirrhosis, fibrosis, and hepatocellular carcinoma.
HCV Treatment
- The combination of interferon and ribavirin was the only available treatment, but it had limited efficacy and poor patient tolerance, due to variable genotype specificity.
- Protease inhibitors became available in 2011.
- Polymerase inhibitors and NS5A inhibitors are also now available.
- Current HCV treatment regimens using polymerase and NS5A cocktails have achieved cure rates approaching 95-99% in clinical trials and real-world scenarios.
HCV Treatments (Specific Drugs)
- Specific medications like SOFOSBUVIR/VELPATASVIR (EPCLUSA), DACLATASVIR (DAKLINZA), OMBITASVIR/PARITAPREVIR/RITONAVIR (TECHNIVIE), LEDIPASVIR/SOFOSBUVIR (HARVONI), and others are used for HCV treatment.
2020: Importance of Hepatitis C Virus (HCV) discovery
- 2020 marked a significant year in medicine, recognizing the discovery of HCV with the Nobel Prize in Physiology or Medicine awarded to Harvey J. Alter, Michael Houghton, and Charles M. Rice for their revolutionary work in discovering HCV.
- The Nobel Prize highlights the achievement of identifying the causative agent of HCV, which has major health implications.
Chronic HCV Importance
- HCV was discovered in 1989.
- Before 1990, blood supplies were potentially tainted with HCV.
- Currently, about 250,000 Canadians have HCV and many are unaware of their infection (40 to 70%).
- Treatment considerations include when to administer treatment and the optimal treatment strategy.
HCV Elimination Efforts in Canada
- Efforts are underway to eliminate HCV in Canada through initiatives such as the Canadian Network on Hepatitis C (CanHepC).
- These efforts aim to improve awareness, diagnosis, and treatment across Canada.
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Description
This quiz covers the diverse group of RNA viruses, including specific examples like coronaviruses and influenza. You'll learn about the symptoms, diagnosis, and treatment options for common RNA viruses and their clinical significance. Test your knowledge on the characteristics and impacts of these pathogens.
