Poxviruses and Rabies

Question 1

describe poxvirus characteristics

Answer 1

DNA, double stranded, asymmetric capsid, both enveloped and uneveloped

Question 2

what characteristics of poxvirus distinguish it from other viruses?

Answer 2

it has an asymmetrical capsid and can be infectious enveloped or unenveloped

Question 3

does the virion require host RNA polymerases?

Answer 3

no, it carries its own.

poxviruses are the only viruses that carry a DNA dependent RNA polymerase with them

Question 4

where do poxviruses form their inclusion bodies?

Answer 4

cytoplasm

Question 5

what do inclusion bodies indicate

Answer 5

they indicate sites of virion or nucleocapsid assembly.

can be used to help distinguish viruses

Question 6

molluscum contagiosum

Answer 6

poxvirus transmitted by intimate cutaneous contact

causes white skin papules- bumps on the skin
much worse in immunosuppressed

resolves on its own w/ t-cell immunity

harmless

Question 7

how is molluscum contagiosum transmitted?

Answer 7

intimate cutaneous contact

Question 8

how long is the incubation period for molluscum contagiosum?

Answer 8

2-8 weeks

Question 9

why can it be difficult to diagnose molluscum contagiosum

Answer 9

grows poorly in culture

Question 10

smallpox characteristics

Answer 10

DNA, double stranded, asymmetric, both enveloped and nonenveloped

Question 11

smallpox transmission

Answer 11

respiratory

Question 12

describe smallpox infection

Answer 12

infects respiratory mucosa and lymph,

establishes viremia that attacks lungs, liver, spleen

second viremia infects skin

Question 13

what is the clinical presentation of smallpox

Answer 13

papules, vesicles, pustules.

lesions in oral mucosa are the main source of new infection

Question 14

smallpox virus vaccine

Answer 14

live- vaccinia virus

Question 15

how many serotypes of smallpox are there?

Answer 15

1

Question 16

how many other animals act as resevoirs for smallpox?

Answer 16

0- just humans

Question 17

complications of smallpox vaccinations

Answer 17

encephalitis

vaccinia necrosum- spreading necrosis at site of infection d/t t-cell immunity

eczema vaccinatum- pread of lesion in pre-exisitng eczema

generalized vaccinia- spread of lesions in the absence of eczema

heart infection

Question 18

when is the smallpox vaccination useful?

Answer 18

prior to infection or w/in 4 days of infection

Question 19

what other treatments work for small pox

Answer 19

passive immunization w/ IgG

Question 20

rhabdovirus characteristics

Answer 20

RNA, single stranded, minus strand, enveloped, helical

rabies

Question 21

rabies transmission

Answer 21

bite from infected animal

Question 22

rabies infection

Answer 22

no viremia- tropism for nervous system

replicates into salivary glands

Question 23

incubation period of rabies

Answer 23

week to months

Question 24

rabies prognosis untreated?

Answer 24

human and canines- fatal

Question 25

rabies symptoms

Answer 25

fever, anorexia

Later: hydrophobia (d/t swallowing pain), paralysis, coma, death

Question 26

rabies diagnosis

Answer 26

negri bodies- cytoplasmic inclusions in nerve cells

uses fluorescent Abs to confirm

Question 27

where are herpes inclusion bodies?

Answer 27

nucleus

Question 28

rabies vaccine

Answer 28

killed vaccine

can be given any time during the incubation period, but once CNS symptoms begin, will not stop death

Question 29

rabies treatment

Answer 29

combination of passive and active

IgG given to delay symptoms and then killed vaccine used to activate active immunity

used in all cases of unknown bites or prophylactically w/ vets

Question 30

how does transmission usually occur in the US?

Answer 30

bites from wild animals’ (bats, foxes, racoons, etc.)

dogs are not a big source (except near mexican border) b/c of vaccination requirements