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Flashcards in Lecture 16 Deck (82):
1

types of non enveloped RNA viruses

polio virus, coxsaki virus, Hepatitis A, Rhino virus, Rota virus

2

Types of enveloped RNA viruses

influenza, measels, mumps, rubella, rabies, retro virus (HIV, HTLV)

3

What does Influenze virus cause?

flu epidemic/pandemic

4

3 serological types of influenza

A, B, C

5

Define envelop of influenza virus

has two types of spikes- hemaglutinin & Neuraminidase- the envelop protein determines type specificity

6

Other name for influenza virus

orthomyxovirus which interacts with mucin and has an 8 segmented genome

7

What is the present strain causing swine flu?

H1N1

8

Who is the influenza A virus present in?

humans- also in birds, chicken, sqine and horses-- sources for antigenic shift and pandemics

9

Who is the influenza B virus present in?

humans only!

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Transmission of influenza

air born- respiratory droplets- group A- antigenic shift every 10/11 years- group B is antigenic shift yearly

11

When does the infection of influenza occur?

in winter months; restricted respiratory tract- systemic symptoms ar not due to viremia

12

What are systemic systems of influenza due to?

due to circuating cytokines

13

What gives immunity to influenza?

IgA, IgG

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clinical features of influenza

24-48 hours-- will have fever, myalgia, sore throat, cough- sudden onset. Resolves spontaneously in 4-7 days

15

Treatment for influenza?

Zanamvir & Tamiflu- inhibits release of virus from cell- effective against A and B
Amantadin effective against A

16

What is the natural host of Measles

single serotype- humans are the natural host

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Transmission of Measles

transmission by respiratory droplets- world wide distribution-

18

What stage is Measles highly contagious in?

prodromal stage- non infectious after development of rashes- cough and sneezing spread disease

19

How often does the Measles epidemic occur?

once in 2-3 years

20

Clinical features of Measles?

fever, photophobia, runny nose and cough- red spot with white center on buccal mucosa of oral cavity

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Define development of rash in Measles

rashes develop on face and then spreads downwards- become brownish several days later

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What affect can measles have on pregnant women?

still births in pregnant women- affords life long immunity

23

Complications of measles

encephalitis- very rare
Sub acute schlerosing Pan- can develop years later but rare

24

Lab diagnosis for Measles

NONE- diagnosed on clinical grounds

25

Is there an antiviral drug for Measles?

NO

26

Prevention of Measles

live attenuated vaccine- given at 15 months or later because before then vaccine will have no effect because maternal Abs still present

27

Define Mumps

single sero type- infects URT and blood spreads to parotid gland, testes, ovaries, pancreas and sometimes meningitis

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Can you get mumps more than once?

NOPE

29

How is mumps transmitted?

through respiratory droplets- world wide distribution- peak incidence in winter

30

What percentage of children have mumps without symptoms and are therefore immune?

30%

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Clinical manifestations of Mumps

18-21 days- fever, malaise, followed by tender swelling in parotid gland- disease is benign- resolves spontaneously

32

Complications of mumps

If the disease occurs in post pubertal males, it can cause orchitis which may cause infertility

33

Medication for mumps

NONE- prevention through MMR vaccine

34

What does respiratory syncytial virus cause?

pneumonia and bronchiolitis in infants

35

What is on the surface of the virus for respiratory syncytial virus?

fusion proteins only- no hemaglutinin/neuraminidase

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natural host of respiratory syncytial virus?

humans and chimpanzees

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Transmission of respiratory syncytial virus

respiratory droplets/direct contact with nose and mouth by finger- outbreaks occur every winter world wide- everyone infected by age 3

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Clinical features of respiratory syncytial virus?

bronchiolitis, pneumonia, otitis media in young children. In adults it causes common cold

39

Treatment of respiratory syncytial virus?

Aerosolised Ribovirin in severe infections- no vaccine available

40

What does Para Influenza virus cause?

CROUP- acute laryngo tracheo bronchitis inc hildren

41

Transmission of para influenza

respiratory droplets- world wide in winter

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What do the majority of para influenza cases cause?

sub clinical infection- no antiviral drug or vaccine (self limiting)

43

What does Rubella virus cause?

German measles - single serotype

44

Transmission of Rubella virus

respiratory droplets, placental transmission from mother to fetus

45

How often does epidemic of rubella virus occur?

every 6-9 year

46

Clinical manifestation of rubella

milder and shorter disease- causes fever, malaise, followed by rashes from face to trunk and limbs- lymph node enlargement behind ear lobe

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How often do rashes from rubella last?

3 days then disappear

48

What happens if rubella occurs while a woman is in her first trimester?

teratogenic effect in infants- heart, eye, and brain will be affected, causing cataract, deafness, mental retardation, PDA (Rubella syndrome) - these children excrete viruses for a long time

49

Shape of virus for rabies?

bullet shaped virus- single antigenic type

50

rabies hosts?

mammals, skunks, raccoons, bats and dogs

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How do humans get infected with rabies?

through animal bite- non bite transmission through respiratory aerosol from bats secretion

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How does the rabies bite affect the body?

moves from bite site to CNS: multiplies in brain tissue and then spreads through peripheral nerves to salivary glands- encephelitis in brain

53

Any immunity for rabies?

NO- because no survivors

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Clinical manifestations of rabies

infectious for 2-16 weeks- shorter time if site is near to head- prodromal symptoms, fever, anorexia, confusion, lethargy, increased salvation
within a few days goes into coma and dies

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Diagnosis of Rabies

negri bodies can be demonstrated from corneal scrapings and autopsy specimen - no antiviral drug

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Prevention of rabies

pre exposure, immunization with rabies vaccine to vets and zoo keepers

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Can a rabies vaccine be given after infection?

YES

58

How do you treat rabies bite?

wound should be cleaned and cauterized

59

If rabies symptoms develop in animal what is done?

euthanization

60

What does Polio virus cause?

poliomyelitis in children

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Host of Polio Virus?

Primates (Apes and Monkeys), man

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Discuss serotypes of Polio

3 serological types- protection requires vaccine for all three types

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Transmission of Polio

by fecal-oral route: replicated in oro-pharynx and intestinal tract

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Pathogenesis of POlio

after replication, it spreads through blood to CNS- infects motor neurons in ventral horn of spinal cord- death of neurons results in paralysis

65

Immune response for polio

intestinal IgA, humoral IgG

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Clinical features of polio?

mostly asymptomatic- only 1% of infection manifests symptoms
brief fever, patient develops flaccid paralysis of one or both limbs, motor nerve degeneration is permanent

67

For how long does patient excrete polio virus in feces?

6 months

68

Prevention of polio

2 vaccines available
killed vaccine- IPV
live vaccine- OPV
3 doses given once monthly

69

What are the 2 groups of Coxsackie virus?

A - infects skin and mucous membranes
B- infects internal organ

70

How is Coxsackie virus transmitted?

fecal-oral route

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Where does Coxsackie virus replicate?

oropharynx and GIT- common in summer

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Clinical manifestations of Group A Coxsackie virus?

Herpangina- fever, sore throat, vesicles in oral cavity; acute hemmorrhagic conjunctivitis; foot and mouth disease

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What is Foot and mouth disease?

rashed in hand, foot and ulcerations in the mouth- children

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Clinical manifestations of Group B Coxsackie virus?

Pleurodynia- fever, with severe pleuritic chest pain; myocarditis and preicarditis- fever, chest pain, CCF

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Vaccine for Coxsackie virus?

NO- and no antiviral drug

76

What does rhino virus cause?

common cold in winter months

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host of rhino virus

human and chimpanzees

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Transmission of rhino virus?

aerosol, hands, fingers and towels

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Clinical manifestations of rhino virus

sneezing, nasal discharge, sore throat, head ache and chilly sensation- lasts for a week

80

Is there a vaccine for rhino virus?

NO- can offer vitamin C in high doses, Zn gluconate lozanges

81

Transmission of rota virus?

fecal-oral route: common in children

82

Clinical features of rota virus

gastro enteritis, watery diarrhea