Confidence

1
Confidence
2
The Hot Zone
3
General Features of Viruses 1

• Obligate Intracellular Parasites
• Very small (ultramicroscopic)
• Non-cellular
• Not Alive
• Protein Coat Capsid
• Envelopes

4
(No Transcript)
5
General Features of Viruses 2

• Utilization of Host Cell Machinery
• Host Range
• Genome
• DNA or RNA but NOT both
• Single stranded or double stranded
• Enzymes (Polymerases)

6
Virus Replication (5 Basic Steps)

1. Adsorption
2. Penetration
3. Replication
4. Maturation
5. Release

7
Viral Replication (5 basic steps)
8
Bacteriophage Multiplication Cycle

• Lytic Cycle

9
Lysogenic Cycle
Movie
10
DNA Viruses
11
RNA Viruses
12
Consequences of Infection
Cytopathic Effect (CPE) Latency Transformation
Oncogenic viruses
13
Animal Viruses------DNA

• Pox

Enveloped Large/complex virus
SMALLPOX
14
Animal Viruses------DNA

• Herpes
• latency recurrent infections
• Herpes is Forever
• Large, enveloped virus
• complications of latency recurrent infections
  become more severe with age, cancer chemotherapy,
  etc
• Among the most common serious opportunists
  among AIDS patients
• Herpes Simplex Virus

Herpes simplex virus can enter both neuronal and
skin cells but achieves latency only in neurons
15
Herpes Simplex Virus-1 Latency in trigeminal
nerve ganglion
16
Herpes Cure?

• There is no treatment that can cure herpes, but
  antiviral medications can shorten and prevent
  outbreaks during the period of time the person
  takes the medication.  In addition, daily
  suppressive therapy for symptomatic herpes can
  reduce transmission to partners. (from CDC
  fact sheet)
• Treatment parody http//www.youtube.com/watch?vj
  LBTXe1R3VE

17
Herpes Varicella-Zoster (Chicken Pox/Shingles)
Early symptoms are acute pain and redness of
dermatome followed by rash
Chickenpox
Shingles
18
Epstein-Barr Virus (EBV)

• infects lymphoid tissue salivary glands
• transmission direct oral contact
  contamination with saliva
• by mid-life 90-95 of all people are infected.
• causes mononucleosis sore throat, high fever,
  cervical lymphadenopathy
• Because of great sanitation in U.S. 70 of
  college-age Americans have never had the
  infectionso a very vulnerable population for
  mono
• Long incubation period (30-50 day incubation)
• most cases of infection are asymptomatic

19
Animal Viruses------DNA

• Parvo

Single-stranded DNA virus Very small nonenveloped
virus Important disease in domestic
animals-causes distemper in cats, enteric disease
in dogs, fatal cardiac infection in puppies
20
Parvoviruses
B19 variety causes fifth disease, (erythema
infectiosum), rash of childhood Child may have
fever rash on cheeks Severe fatal anemia can
result if pregnant woman transmits virus to fetus
slapped face rash of fifth disease. Parvovirus
B19
21
Papillomavirus
Common wart
Plantar wart
Genital wart
22
Papillomavirus

• papilloma benign, squamous epithelial growth or
  wart
• caused by 40 different strains of HPV
  (nonenveloped DNA virus)
• Common warts (seed warts) on fingers, etc
• plantar warts on soles of feet
• genital warts prevalent STD
• transmissible through direct contact or
  contaminated fomites, autoinnoculation
  (self-spread)
• Incubation 2 weeks to more than a year
• For most people the virus goes away on its own

23
Genital warts

• most common STD in US?
• over 6 M new cases each year
• 20 million carriers (U.S.) of one of the 5 types
  of HPV associated with genital warts
• strong association with cervical penile cancer
• CDC estimates sexually active people have a 50
  chance of catching HPV during a lifetime

24
HPV Vaccine

• For girls and women 9-26 years of age
• Three doses
• Initial
• 2 month booster
• 6 month booster
• For prevention onlynot a treatment

25
Animal Viruses------RNA

• Paramyxoviruses
• Measles
• Mumps

26
How Iowa Got the Mumps
How Iowa Got The Mumps

• In 2006 Iowa got the mumps. Over 2000 individuals
  got mumps infection in the first half of 2006 (in
  a normal year there are on average 5 cases per
  year)
• Probably originated
• in the UK?

26
27
Influenza
28
Animal Viruses------RNA

• Orthomyxoviruses INFLUENZA
• Influenza A (circulates in many species)
• Influenza B (circulates widely only in man)
• Influenza C (mild illnessnot thought to cause
  epidemics)
• Antigenic Drift (small changes that happen
  continually over time)
• Antigenic Shift (abrupt major change in the
  virus)

29
Shift and Drift
Yearly variations in the Seasonal Flu are the
result of antigenic drift.
30
Vaccination for seasonal flu

• There are two types of vaccines
• The "flu shot" an inactivated vaccine
  (containing killed virus) that is given with a
  needle, usually in the arm.
• The nasal-spray flu vaccine a vaccine made with
  live, weakened flu viruses that do not cause the
  flu (sometimes called LAIV for live attenuated
  influenza vaccine or FluMist). LAIV (FluMist)
  is approved for use in healthy people 2-49 years
  of age who are not pregnant.
• Each vaccine contains three influenza viruses-one
  A (H3N2) virus, one regular, seasonal A (H1N1)
  virus, and one B virus. The viruses in the
  vaccine change each year based on international
  surveillance and scientists' estimations about
  which types and strains of viruses will circulate
  in a given year.
• About 2 weeks after vaccination, antibodies that
  provide protection against influenza virus
  infection develop in the body.
• Seasonal flu peaks in the U.S. in Jan and Feb

31
Influenza type A

• acute, highly contagious respiratory illness
• seasonal, pandemics
• among top 10 causes of death in US
• respiratory transmission
• binds to ciliated cells of respiratory mucosa
• causes rapid shedding of cells, stripping the
  respiratory epithelium, severe inflammation
• fever, headache, myalgia (muscle pain),
  pharyngeal pain, shortness of breath, coughing
• treatment amantadine, rimantadine, zanamivir
  oseltamivir
• annual vaccine

32
(No Transcript)
33
2009 H1N1swine flu
34
(No Transcript)
35
Animal Viruses------RNA

• Orthomyxoviruses INFLUENZA
• Is an Avian Flu pandemic on the way??

36
Avian Flu
37
Avian Flu
38
Avian Flu
39
Avian Flu

• Why would Bird Flu be a big deal?
• Pandemic viruses appear as the result of
  antigenic shift, which causes new combinations of
  proteins on the surface of the virus. If the new
  virus spreads easily from person to person a
  pandemic can result.

40
Avian Flu

• Culling of infected Poultry

41
NOVA Science NOWPandemic flu video (2006)

• http//www.pbs.org/wgbh/nova/sciencenow/3302/04.ht
  ml

42
More RNA Animal Viruses

• Togaviruses (Flavivirus subcategory)
• Dengue
• Yellow Fever
• West Nile

43
Dengue
American countries with laboratory-confirmed
hemorrhagic fever (red shaded areas), prior to
1981 and from 1981 to 1997.
Distribution of Aedes aegypti (red shaded areas)
in the Americas in 1970, at the end of the
mosquito eradication program, and in 1997
44
Dengue
45
West Nile Virus-1999-2001
46
West Nile Virus-2002
47
West Nile Virus 2004 (march 3rd)
48
West Nile Virus 2005 (Jan 11Th)
49
West Nile Virus - Life Cycle
50
Animal Viruses------RNA

• Picorna (a nonenveloped small RNA virus)
• Polio (generally fecal-oral transmission, also
  shed in throat. Spread by contact with infected
  person or drinking water)
• Hepatitis A (fecal-oral transmission)
• Foot and Mouth Disease Virus (FMDV)
  (foreign animal
  diseaseobject of extreme surveillance)

51
Polio

• Polio (poliomyelitis) mainly affects children
  under five years of age.
• One in 200 infections leads to irreversible
  paralysis (usually in the legs). Among those
  paralysed, 5 to 10 die when their breathing
  muscles become immobilized.
• Polio cases have decreased by over 99 since
  1988, from an estimated 350,000 cases then, to
  2000 reported cases in 2006. The reduction is
  the result of the global effort to eradicate the
  disease.
• In 2008, only four countries in the world remain
  polio-endemic, (Afghanistan, India, Nigeria and
  Pakistan).
• An inactivated polio vaccine rather than the
  oral modified live vaccine is used in the US
  today.

52
FMDV
UK 2001 outbreak 2030 cases. 6 million animals
were culled (4.9 million sheep, 0.7 million
cattle and 0.4 million pigs), which resulted in
losses of some 3.1 billion to agriculture. A
lesser outbreak occurred in 2007 but importation
of UK meat and dairy products were banned by many
countries.
53
Ebola Virus a Filovirus (RNA virus)
Ebola is a virus-caused disease limited to parts
of Africa. Within a week, a raised rash, often
hemorrhagic (bleeding), spreads over the body.
Bleeding from the mucous membranes is typical
causing bleeding from the mouth, nose, eyes and
rectum.
54
Hanta Virus a Bunyavirus (RNA virus)
Hanta virus is found worldwide (including the
US). The virus is spread by human contact with
rodent waste. Dangerous respiratory illness
(Hantavirus Pulmonary Syndrome) develops.
Effective treatment is not yet available and over
50 of cases end in fatality.
55
Coronavirus

• Coronaviruses
• SARS (severe acute respiratory syndrome)
• 2003 Outbreak
• 8,098 people worldwide became ill, 774 died.
  Spread to 30 countries before the outbreak was
  contained.

56
SARS
57
Coronavirus

• Coronaviruses
• SARS (severe acute respiratory syndrome)
• Global Spread
• Feb 21,2003 infected medical doctor from
  Guangdong Province spent a night at a Hong Kong
  hotel. 12 people staying at or visiting that
  floor of the hotel became infected.
• These travelers then dispersed the disease to
  other countries worldwide

58
SARS Dispersal
Superspreaders 144 of Singapores 206 cases
linked to contact with just 5 individuals
59
Palm civets (SARS reservoir??)
Did the SARS epidemic start in Guangdong
Province, China as a civet meal?
Masked Palm Civet at market
Water rat at a market
60
Cost of SARS
61
Rabies

• Rhabdoviruses RABIES
• Only 1 or 2 human cases per year
• Iowa 1951 then not again until 2002

62
Rabies

• Rhabdoviruses RABIES

63
Rabies

• Rhabdoviruses RABIES

64
HIV ( a retrovirus)

• Worsening Epidemic in Africa
• 25 million Africans have HIV
• Africa has 11.6 million AIDS orphans.
• At the end of 2007, women accounted for 50 of
  all adults living with HIV worldwide, and for 59
  in sub-Saharan Africa
• United Nations warns that the next two decades
  could see 89 million new cases
• Up to 10 of the continents population

65
HIV Worldwide
Global trends
The number of people living with HIV has risen
from around 8 million in 1990 to 33 million
today, and is still growing. Around 67 of people
living with HIV are in sub-Saharan Africa.
66
HIV
67
Opportunistic infections
68
Viroids
Cadang cadang viroid
Tomato plants - and for Potato spindle tuber
viroid
69
Prions

• Scrapie
• Mad Cow Disease
• Bovine Spongiform Encephalopathy (BSE)
• Creutzfeldt-Jakob Disease
• Chronic Wasting Disease (deer and elk)

70
Prion CWD

• Chronic Wasting Disease

Chronic Wasting Disease Among Free-Ranging
Cervids by County,United States, January 2007
71
CWD in Iowa???

• 2006-2007 season over 4,000 deer tested-none
  positive
• Since 2002 over 20,000 deer tested without a
  positive

2006-2007 tested deer