Poxvirus/Rabies

Question 0

Transmission of molluscum contagiosum

Answer 0

Intimate cutaneous contact

Question 1

Structure of poxvirus

Answer 1

“double-stranded DNA, protein, and lipid. They have the largest nucleic acid content of all animal viruses. The virion contains a RNA polymerase (DNA dependent RNA polymerase–“Poxviruses are the only DNA viruses that have a gene for their own RNA polymerase.”).”
“large and brick-shaped”
“Enveloped, or unenveloped (stable to unfavorable conditions like drying)”—both infectious and have antibodies against each.
“form inclusion bodies in the “””"”cytoplasm.”

Question 2

Clinical symptoms of molluscum contagiosum

Answer 2

“incubation period of 2 to 8 weeks pearly white papules appear. The disease is self-limiting (but this may take months or years).”
Difficult diagnosis
Severe in immunosuppression

Question 3

Transmission of smallpox

Answer 3

“via the respiratory route. Initial mild upper respiratory infection with growth in mucosa and lymph nodes”

Question 4

Clinical symptoms of smallpox

Answer 4

First viremia, infects lungs, liver, spleen
Second viremia, infects skin
“Clinical presentation is papules, vesicles, pustules. Lesions in the oral mucosa are main source of new infections which result from inhalation of aerosols. Dried virus in pustule crusts is also infectious.”

Question 5

Prevention of smallpox

Answer 5

“Smallpox has been eradicated by immunization with the live vaccine”

“The ring vaccination strategy worked for smallpox because post-exposure vaccination (given within 4 days after exposure) is effective. There are no non-human reservoirs. There is a single serotype.”

Question 6

Complications of smallpox vaccination

Answer 6

“encephalitis: Possibly more common after primary vaccination and possibly more frequent in adults.”
“Vaccinia necrosum (progressive vaccinia); spreading necrosis at the vaccination site. Result of a defect in cell-mediated immunity”
“Eczema vaccinatum: spread of lesion in pre-existing eczema (inflammation of the skin).”
Myo/pericarditis
Passive immunization with anti-vaccinia abs can help.

Question 7

Structure of rhabdovirus

Answer 7

“The virion is enveloped, bullet shaped, medium sized.”

“helical nucleocapsid contains a single molecule of minus-stranded RNA. The virion contains an RNA-dependent-RNA

Question 8

Transmission rhabdovirus

Answer 8

“the bite of an infected animal that has virus in its saliva”
Does not require viremia
“tropism of rabies virus is directed to nerve cells.”
Viral growth in salivary gland, and CNS (unprovoked attack)
Incubation is long (weeks to months)—allows for immunization after infection
Infection in humans and dogs is always nearly fatal

Question 9

Clinical symptoms of rhabdovirus

Answer 9

“initial symptoms are nonspecific: fever and anorexia. Later symptoms include hydophobia (fear of water due to extreme pain from swallowing). Rabies is actually known as “hydrophobia” in most parts of the world. CNS defects from virus destruction of the neurons accelerates and result in coma or paralysis, which are almost always followed by death.”

Question 10

Diagnosis of rabies

Answer 10

“Diagnosis of rabies depends on histological demonstration of Negri bodies (cytoplasmic inclusions) in nerve cells”

Question 11

Prevention of rabies

Answer 11

“The vaccine is given in 5 doses in several months after exposure. The rabies vaccine is a KILLED vaccine (made in diploid cells and then inactivated).”–“highly immunogenic and completely safe.”
“Prophylactic immunization is recommended for residents of areas where rabies is common, veterinarians, or others at risk”
“Most current rabies cases in the USA have been traced to virus from bats”