CLASS I: Double-stranded DNA
Orthopoxvirus
- OPV are enveloped brick-shaped viruses (350 × 270 nm) containing a double-stranded DNA genome with a size of approximately 200 kb, the ends of which are connected by covalent links
- the different OPV species cannot be distinguished by means of electron microscopy
- OPV are closely related to each other with regard to antigens and show marked homology at the genome level
- The genome of the poxviruses encodes for 150–200 different genes
- Unlike other DNA viruses, poxviruses replicate in the cytoplasm of infected cells in so-called virus factories (Guarnieri inclusion bodies)
- Originally, four different infectious virus particles were distinguished during OPV replication: intracellular mature enveloped virus particles, intracellular enveloped virus particles, cell-associated enveloped virus particles, and extracellular enveloped virus particles. Both intracellular and extracellular viruses play an important part for pathogenesis.
- Intracellular and cell-associated viruses are involved in the spreading of the virus from cell to cell, whereas viruses released from the cell enable the dissemination within the infected organism.
QUESTION 1: Which of the following can be administered to an individual infected with orthopoxvirus?
a. Human Papillomavirus Quadrivalent (Types 6, 11, 16, 18) Vaccine, Recombinant
b. Zoster Vaccine, Live, (Oka/Merck)
c. Vaccinia Immune Globulin Intravenous (Human)
d. Anthrax Vaccine Adsorbed
ANSWER: C
The only product currently available for treatment of complications of orthopox infection is vaccinia immunoglobulin (VIG), which is an isotonic sterile solution of the immunoglobulin fraction of plasma from persons vaccinated with vaccinia vaccine. It is effective for treatment of eczema vaccinatum and certain cases of progressive vaccinia.
Source: http://shelf3d.com/i/Orthopoxvirus

CLASS II: Single- stranded DNA
Human Parvovirus * Parvovirus is a small, single-stranded DNA virus * lack of a lipid envelope makes it resistant to physical inactivation with heat or detergent * The virus targets rapidly growing erythroid progenitor cells, which are found in human bone marrow, fetal liver, human umbilical cord, and peripheral blood * To become infective, the parvovirus attaches to a P antigen receptor * The virus is transmitted through exposure to infected respiratory droplets or blood products and vertically from mother to fetus * Exposure to respiratory droplets is the most common means of transmission. * The incubation period of the infection ranges from four to 14 days but can last as long as 21 days * clinical conditions associated with the infection include erythema infectiosum; arthropathy; transient aplastic crisis; chronic red cell aplasia; papular, purpuric eruptions on the hands and feet (“gloves and socks” syndrome); and hydrops fetalis

QUESTION 2: The following are possible modes of transmission of human harpovirus EXCEPT: a. blood transfusion b. bone marrow transplant c. from mother to baby via the placenta. d. intramuscular immunoglobulins
ANSWER: D.
Transmission is usually via respiratory secretions, but it can also be passed on via blood transfusion, bone marrow transplant, other blood products (but not intramuscular immunoglobulins), and from mother to baby via the placenta.
Source: http://www.patient.co.uk/doctor/parvovirus-infection
CLASS III: Double-stranded RNA
Rotavirus
- Mature virus particles are non-enveloped and possess a multilayered icosahedral protein capsid, of about 75nm in diameter, composed of an outer layer, an inner layer, and a core
- The virus genome consists of 11 segments of double-stranded RNA;
- Viral particles contain an RNA-dependent RNA polymerase and other enzymes capable of producing capped RNA transcripts
- Viral replication occurs in the cytoplasm of infected cells.
- The viruses are capable of genetic reassortment
- Virus cultivation in vitro is facilitated by treatment with proteolytic enzymes, which enhances infectivity by cleavage of the outer capsid polypeptide VP4;
- Virus particles are formed by budding into the endoplasmic reticulum and
- Mature virion particles are liberated from infected cells by cell lysis.
-signs and symptoms that appear are vomiting, watery diarrhea, abdominal pain and a fever which can last 3-8 days on average. All of which are most common in children 5 years and younger.
- The most dangerous part of the rotavirus infection is the possible dehydration. To be more specific vomiting for 2-3 days and diarrhea for 4-5 days can cause a great amount of water loss leading to a isotonic dehydration
- There can also be neurologic symptoms that occur if an electrolyte imbalance becomes severe or direct viral infection of the central nervous system occurs.
- Rotavirus has also been associated with aseptic meningitis, necrotizing enterocolitis, acute myositis, hepatic abscess, pneumonia, Kawasaki disease, SIDS and Crohn's disease."
QUESTION 3: Which of the following is not a way of treating rotavirus symptoms? a. Intake of oral rehydration solutions b. Give antibiotic c. Serve bland foods (bananas, plain pasta, crackers, or toast) d. Give acetaminophen
ANSWER: B.
Antibiotics are not capable of killing viruses