1. Viral Pathogens

2. Herpes viruses
Icosahedral, enveloped, complex, dsDNA virus
 Herpes simplex virus type 1 (HSV1)
 Herpes simplex virus type 2 (HSV2)
 Varicella Zoster Virus (VZV)
 Cytomegalovirus (CMV)
 Epstein-Barr Virus (EBV)
1 and 2 most common

3. Herpes Simplex Virus
type 1
•Vesicles: lips, eyes, nose
•MOT
•Saliva, contact
•80% infected (childhood)
•Highly contagious
•Treatment
•Acyclovir
•Prevention
•Avoid contact

4. Latent Herpes
• Replication at initial infection site
• Migration up neuron
• Latent in trigeminal nerve
• Replicates in nucleus of nerve cell
• Triggers: sunlight, hormones, stress, trauma,
fever
Karatitis is leading cause of blindness in the US

5. Herpes Simplex Virus
type 2
• Painful, itchy vesicles or ulcers
• MOT
• Oral, vaginal, anal sex
• 1 in 4 over 30 infected
• 50% asymptomatic
• Treatment
• Acyclovir shortens viral shedding
• Prevention
• Avoid contact
Know two treatments for herpes in general

6. Varicella Zoster Virus
• Chickenpox in children, shingles in adults
• MOT
• Respiratory route
• Prevention
• Chickenpox vaccine for children
• Zostavax against shingles in adults over 60
Maculopapular – raised red bumps
Chickenpox less dangerous before puberty
Can only get shingles after chickenpox

8. Cytomegalovirus (CMV)
• Congenital abnormalities: deafness, jaundice,
enlarged liver and spleen
• MOT
• Through placenta, breast milk
• Saliva in children
• Sexual in adults
Can also cause abortion

9. CMV
• Treatment
• Ganciclovir
• Prevention
• Screening blood transfusions and organ donors
• Safe sex

10. Epstein-Barr Virus
• Infectious mononucleosis
• 90% adults have antibodies
• Latent in B lymphocytes
• Burkitt’s lymphoma in Africa
• MOT
• Transmission in saliva
• Kissing disease
• Self-limiting: 2-3 weeks

11. http://www.hopkins-gi.org/
http://www.phoenixcme.org/
Hepatitis
• Inflammation of the liver
• Jaundice

12. • HAV
• Picornavirus
• Small RNA
• Non-enveloped, (+)ssRNA
• HBV
• Hepadnavirus, enveloped, circular DNA (mostly ds)
• Hepa- DNA
• HCV
• Flavivirus, enveloped (+)ssRNA
Hepatitis Viruses

13. HAV prevelance

14. HAV
• Asymptomatic, or fever, nausea, anorexia, vomiting,
jaundice, dark urine, pale feces
• Not chronic, no carriers, no permanent liver
damage, or cancer risk
• MOT
• Fecal-oral (oysters)
• Treatment
• Self-limiting
• Prevention
• HepA vaccine for foreign travel, personal hygiene

15. HBV
•MOT
• Blood and bodily fluids
• 10% become chronic carriers, liver cancer risk
•Treatment
• α interferon
•Prevention
• IgG
• HepB vaccine

16. HCV
•MOT
• Blood and body fluids
• 1.5% of U.S. population
• 75% become chronically infected
• Hepatocellular carcinoma
•Treatment
• α interferon
•Prevention
• No vaccine available
• Screen blood products (since 1992)

17. Human Papillomavirus
(HPV)
•Icosahedral, non-enveloped dsDNA
• Most common STD in the US (Over
80% by age 50)
• Warts (skin or genital)
• Predisposition to cervical cancer
•Prevention
• Safe sex
• Gardasil (2007) for ages 9-26

18. Influenza Virus
•Helical, enveloped, (-)ssRNA, segmented
• Influenza A, B and C
• Influenza A: Wild bird reservoir
• Shifts a lot
• Spanish flu of 1918: 50 million deaths world
wide
•MOT
•Droplet transmission
•Antigenic drift: Continuous, gradual process of
antigenic change
Orthomyxo virus

19. • Re-assortment via co-infection of two strains.
• High pandemic potential.
• Occurs approximately every 30 years.
Antigenic Shift

20. Antigenic drift vs
antigenic shift

21. Crossing the species
barrier

22. Paramyxoviruses
• Helical, enveloped, (-)ssRNA
• Measles
• Mumps
• Respiratory syncytial virus

23. Measles (Rubeola)
•MOT
• Droplet infection, highly contagious
• Koplik's spots: red lesions with
white center in mouth, followed by
raised maculopapular rash
• Humans are only reservoir
•Self-limiting, life-long immunity
•MMR vaccine

24. Mumps virus
•MOT
• Droplet transmission
• Inflammation of salivary (parotid) glands
• Swelling of jaw and neck
• Enters blood, infects testes (sterility), ovaries
• Infection of testes is called
• Orcitis??
•Self-limiting: 1 week
•Prevention
• MMR vaccine

25. Respiratory Syncytial
Virus
•Pneumonia and bronchitis in infants
•MOT
• Droplets, hand-to-nose, hand-to-
mouth
•Treatment
• Oxygen, suction of mucus or
intubation if severe
• Usually self-limiting
•No vaccine

26. Togavirus
• Icosahedral, enveloped, (+)ssRNA
• Rubella
• Eastern Equine Encephalitis (arbovirus
[transmitted by insects])

27. German Measles
(Rubella)
•Maculopapular rash starts on face
•Teratogenic effect
•Developmental malformations in fetus
•MOT
•Respiratory and transplacental
•Replication in nasopharynx and lymph nodes
•Prevention
•MMR vaccine

28. Variola
• Smallpox: complex, enveloped, dsDNA
• Respiratory droplet and fomites
• Global eradication 1977 (Somalia)
• Pustules, crust and scar
• Prevention
• Vaccine (military and research)
25-30% fatality
2 weeks before effects
Eradicated because:
-Human only reservoir
-Ring vaccination

29. Smallpox
• CFR 30-80%
• Vaccination in India and China
1000 BCE
• 1700s leading cause of death in
Europe
• Bioterrorism agent
• 1796 Jenner vaccine

31. Rabies Virus
(-)ssRNA, enveloped, rhabdovirus, helical. Bullet shaped
Just need to know basic words at the bottom

32. Rabies
 Replication at site of inoculation
 Enters and replicates in the CNS
 Spreads to brain
 2 weeks to 18 months after bite
 Symptoms of disease = 100% death
 Treatment
 Post exposure prophylaxis
 Prevention
 Vaccinate animals

33. Rabies
 Negri body (site of virus replication)
 Inclusion inside cytoplasm of neuron
 Diagnostic finding in brain tissue
Only shown after death through
biopsy

34. Rabies symptoms
 Highly variable
 Fever, anorexia, headache, myalgia
 Nausea, vomiting, hydrophobia (20-50%)
 Confusion, hallucinations, seizures, paralysis
 Coma, respiratory failure, death
 Rabid animals: aggressive behavior, excessive
salivation

35.  Canines remain the most important reservoir
world wide (Latin America, Africa, and Asia)
 Vaccination of cats and dogs in the US keeps
number low
Bats too

36. Enteroviruses
 Poliovirus: Naked, icosahedral, + strand
RNA
 Rotavirus: transient envelope, icosahedral
dsRNA

37. Poliomyelitis
 Fecal-oral (humans only)
 Replicates in intestine then spreads to CNS
 Destroys motor neurons in brain: muscle
paralysis
 In brain stem: respiratory paralysis and death
 Flaccid paralysis, especially lower limbs,
asymmetrical, muscle wasting.
Two different vaccines that were used, Salk and Sabin
Salk – Dead, intravenous, used in the US
Sabin “OPV” – Oral, intenuated, used in third world countries, more risky
In the picornavirus family

38. Polio
 1952 outbreak with 60,000 cases (3,000 deaths
in the U.S. alone), mostly Children
 Vaccine in 1955, eliminated from US in 1979
 600,000 survivors in U.S.
 1920s
 FDR - president
 Iron lung
Getting polio back then wasn’t so bad, bad hygiene meant kids got it, and it was just a
gastrointestinal bug, now with better hygiene they are getting it older and older, and it’s
much worse.

40. Rotavirus
 Most common cause of gastroenteritis in
children
 600,000 world wide die (children under 5)
 50,000 hospitalized/year in U.S.
 MOT
 Fecal/oral
 Prevention
 2006 Rota Teq

41. Norwalk Virus
 Icosahedral, ssRNA, naked
 Outbreaks of gastroenteritis in schools, camps and
cruise ships
 Very contagious: ID50 of 10 virions
 50% of all food-borne outbreaks
 Can survive wide temp ranges and up to 10ppm (parts/mil)
chlorine
 Nausea, vomiting, diarrhea
 MOT
 Fecal-oral
 Self-limiting 12-24 hours
Two bucket disease

42. Viruses that cause colds
(200 types)
 Adenovirus
 Coronavirus (also causative agent of SARS)
 Rhinovirus (most common cause)
 Droplet and hand transmission
 Mild upper respiratory symptoms
 Self-limiting (can last up to two weeks)

43. Progression of a runny
nose
 Clear mucus: to clear the virus from nose
and sinus
 White or yellow: white blood cells due to
immune response
 Green: bacteria that are NF come back

44. Arboviruses
 Arthropod-borne viruses (mainly mosquito)
 Life cycle is typically bird-mosquito-bird
 Certain conditions lead to spillover into humans
 Eastern Equine Encephalitis
 West Nile virus
 St. Louis Encephalitis

45. Encephalitis
 Fever, headache, nausea, vomiting
 Confusion, stupor, coma
 WNV: most asymptomatic or recover
 SLE and EEE high mortality rate and morbidity
 No human vaccine
 Prevention is mosquito control

47. Dengue
 A leading cause of death in the tropics
 100 million infected annually
 Four serotypes: no cross protection
 Worse off after getting one kind of serotype then getting
another kind
 No vaccine
 Break bone fever
 Joint pain
 Dengue hemorrhagic fever

48. Yellow Fever
• Flavivirus, +strand RNA virus
• Two cycles of YF
• Yellowing of skin, bleeding
• from nose eyes and mouth
• Historical impacts
• U.S. epidemics
• Haiti
• Panama canal

49. Ebola
 - strand RNA virus belonging to family Filoviridae
 Severe, often fatal disease – hemorrhagic fever
 Sporadic outbreaks since 1976
 CFR (Case Fatality Rate): 90%
 Natural reservoir: fruit bat
 Many cultural barriers exist to prevention of spread
 Burial rituals
 Reuse of needles
 Rural conditions with inadequate supplies

50. Hantavirus
 - strand RNA virus, segmented,
 Family: Bunyaviridae
 Rodent urine and droppings
 Headache, fever, shortness of breath, non-
productive cough
Hanta virus is a distant cousin of Ebola virus,
but is found worldwide. The virus is spread by
human contact with rodent waste.
Dangerous respiratory illness develops.
Effective treatment is not yet available and
over 50% of cases end in fatality

51. HIV
 Lentivirus, Retrovirus, ssRNA, envelope
 Reverse transcriptase
 Glycoprotein spikes attach to CD4 receptors
on helper T cells and some macrophages
 Body fluids, and blood. Sex, needles,
transplacental, breast milk
 Active and latent infection
Secondary infection: T cells are debilitated
HIV can hide in T cells and go undetected.

52. Organization of HIV-1
Virion
Just need to know spikes are glycoprotein

53. How HIV evades host
immune system
• Integration into host DNA
• Mutation: 1 million variants in early stage
and 100 million in end stage