Feces survey finds new viruses.
14 October 2003
The first genomic analysis of human feces
reveals
that our guts are teeming with 1,200
different viruses, more than
half of which are unknown to science.
Learning more about these viruses may lead to
new ways to manipulate the microscopic ecology of our
intestines. "They could completely change the ecology of the
gut,” says Forest Rohwer of San Diego State University,
California, who led the study.
The
vast majority of the species identified don't upset our
stomachs. Most are phages - viruses that infect and kill
bacteria. "These are some of the biggest predators of
bacteria," he says.
Up to 500 types of bacteria digest our food and
regulate our bowels' health.
What is the most
numerous intestinal bacterium?
What bacterial
“predator” did we use in lab?
Where would you go to
collect coliphage?
Capsomere TEM - rotavirus
Norwalk-like virus (rotovirus)
Outbreaks of Gastroenteritis Associated with Noroviruses
on Cruise Ships - United States, 2002
Cruise line A
cancelled a subsequent cruise and voluntarily took the
ship out of service for 1 week for aggressive cleaning
and sanitizing. No outbreaks were reported on
subsequent cruises.
Papovaviridae - dsDNA, naked virus
Warts/Cancers
Enveloped virus
Chickenpox
Infectious mononucleosis
Epstein-Barr virus
90% in
U.S. carry Epstein-Barr
Kaposi's
sarcoma
Aids patients
connective
tissue cancer
Poxviridae - dsDNA, enveloped
Cowpox,
smallpox, monkeypox
Animal
to human transmission
Edward Jenner - ill-advised experiments
Developed
the first smallpox vaccine in 1796.
Noticed
milk maids (in background) did not get smallpox,
only cowpox.
Was so
confident in his experiment he injected cowpox
fluid into a farmer’s son, later injected
infectious smallpox.
Kid did
not contract smallpox.
Hepadnaviridae - dsDNA, enveloped
Hepatitis
Blood borne pathogen
Picornaviridae - ssRNA (+), no envelope
[polio, colds, hepatitis A]
Virus
attaches to receptors on nasal cells.
Poliovirus - ancient
Pharaoh Ramses V
Paralytic Polio
Inactivated polio vaccine
(Salk)
Mass vaccination programs
Cutter incident
260 people contracted polio from a
bad batch of vaccine.
Vaccination still has many doubters.
Live’ oral polio vaccine (Sabin)
Attenuated virus =
disabled virus
Hepatitis A virus
Hepatitis transmission
Fecal/oral through uncooked
food
Hepatitis A Associated with
Consumption of Frozen Strawberries
-- Michigan, March 1997
Filoviridae - ssRNA (-), enveloped
Marburg and Ebola
Orthomyxoviridae - RNA (-),
segmented
Influenza – hemagglutinin
Retroviruses - RNA, contain
reverse transcriptase
Opposite of most
transcriptase
RNA polymerase
Makes DNA from RNA
Can still biosynthesize with
many reading errors
No “proofreading” or exo-nucleases
Changes make treatment/drug
therapy difficult
Retrovirus - HIV
Mad
Cow Disease (BSE)
• Prions are
recognized as
‘self-replicating’
proteins.
• Are inherited,
transmitted (bad
growth hormone),
and/or consumed.
• Some have been
around for some time (Kuru
from cannibalism)
• Can not be cooked
or even sterilized WHO
recommends no
consumption of infected
animals
•Creutzfeldt-Jakob Disease (CJD)-
Misfolded protein