Positive-Stranded RNA Viruses vs DNA Viruses Quiz

Picornaviridae

• Coxsackie virus causes a spectrum of diseases including Herpangina, Hand Foot Mouth Disease, Hemorrhagic Conjunctivitis, Myocarditis and Pericarditis, and Aseptic Meningitis.
• Hepatitis A virus is transmitted through the fecal-oral route and primarily affects children, causing self-limited hepatitis.
• Anti-HAV IgM is the most important test for Hepatitis A diagnosis.

Caliciviridae

• Hepatitis E virus is transmitted through the fecal-oral route and has no chronic state, cirrhosis, or HCC.
• High mortality is seen in pregnant women infected with Hepatitis E virus.
• Norwalk virus causes viral gastroenteritis, with sudden onset of vomiting and diarrhea accompanied by fever and abdominal cramping.

Reoviridae

• Rotavirus is the most common cause of diarrheal disease among infants and young children.
• Nearly every child in the world is infected with rotavirus at least once by the age of five.
• Immunity develops with each infection, so subsequent infections are less severe.

Hepadnaviridae

• HBsAg indicates the presence of disease (chronic, acute, or asymptomatic carrier) and precedes the onset of symptoms and elevation of liver enzymes.
• HBcAg indicates the duration of infection and is not protective.
• Positive antibodies are seen during the "window period" of active infection.
• Cirrhosis and Hepatocellular Carcinoma are potential complications of Hepatitis B infection.
• Treatment options include Interferon-A and Lamivudine.
• Prevention is achieved through vaccination, which is the first vaccine to prevent a human cancer.

RNA Viruses

• Rotavirus, Astrovirus, Flavivirus, Paramyxovirus, Togavirus, Filovirus, Retrovirus, Coronavirus, Calicivirus, and Picornavirus are all types of RNA viruses.
• Coronavirus can cause severe hemorrhagic fever in people.

Picornaviridae

• Poliovirus replicates in motor neurons in the anterior horn of the spinal cord, causing paralysis.
• The host range is limited to primates due to the binding of the viral capsid protein to a receptor found only on primate cell membranes.
• Transmission occurs through animal bite, with animal reservoirs including dogs, cats, skunks, raccoons, and bats.

Rhabdoviridae

• Rabies virus is a bullet-shaped, enveloped virus with a helical nucleocapsid and one piece of single-stranded, negative-polarity RNA.
• Transmission occurs through animal bite, and the pathogenesis involves local multiplication, axonal transport to the CNS, and encephalitic period.
• Treatment and prevention include pre-exposure vaccination and post-exposure vaccination with immunoglobulin.

Coronavirus

• Coronavirus is an enveloped virus with a helical nucleocapsid and one piece of single-stranded, positive-polarity RNA.
• The virus has a prominent club-shaped spike, forming a "corona".
• There are four main sub-groupings of coronaviruses: alpha, beta, gamma, and delta.
• The virus binds to the ACE-2 receptor, which is highly expressed on pulmonary epithelial cells, and enters the host through endocytosis or membrane fusion.
• SARS, MERS-COV, and COVID-19 are caused by coronaviruses.

Coronavirus - COVID-19

• COVID-19 emerged in Wuhan in late 2019 and is a novel Betacoronavirus.
• The disease course varies widely, including asymptomatic infection, mild disease, moderate disease, or severe disease requiring hospitalization, oxygen therapy, intensive care, and mechanical ventilation.

DNA Viruses

• DNA viruses cannot be translated directly into proteins and must be transcribed into mRNA with subsequent translation into structural proteins and enzymes.
• Parvovirus, Adenovirus, Papillomavirus, Polyoma virus, Hepadna virus, and Poxvirus are all types of DNA viruses.

DNA Viruses - Parvovirus

• Parvovirus B19 is a virus that infects humans only.
• The most common rash associated with parvovirus B19 infection is a red rash on the face, also called a "slapped cheek" rash.
• Characteristics of parvovirus B19 include a naked virus with icosahedral symmetry, a single-stranded DNA genome, and one serotype.
• Transmission occurs through respiratory droplets and transplacental transmission.

DNA Viruses - Parvovirus

• Erythema Infectiosum (Fifth Disease/Parvovirus B19) is characterized by a bright red cheek rash (slapped cheek appearance) with fever, coryza, and sore throat.
• Prevention is achieved through vaccination.

Orthomyxoviridae

• Influenza virus has major antigens hemagglutinin (H) and neuraminidase (N).
• Transmission occurs through respiratory droplets.
• Influenza A causes worldwide epidemics (pandemics), while Influenza B causes major outbreaks and Influenza C causes mild respiratory tract infections.

Orthomyxoviridae

• Antigenic Shift (Pandemics) involves major changes based on the reassortment of segments of the genome RNA.
• Antigenic Drift (Epidemic) involves minor changes based on mutations in the genome RNA.
• Treatment options include Oseltamivir or Zanamivir.
• Prevention is achieved through yearly vaccination/immunization.

RNA Viruses - Paramyxoviridae

• Parainfluenza, RSV, Measles, and Mumps are all types of Paramyxoviruses.
• Parainfluenza primarily affects young children, causing upper and lower respiratory tract infections.