Skin Cancer
Basal
Cell Carcinoma
Most
common - over 500,000 cases per year
Mostly in older people and fair-skinned people
Highly related to amount of sun-exposure
Usually looks
like a pearl-shaped bump with veins
Rodent
ulcer
Treatment
Removal - surgery, freezing, lazer
Rarely spreads
Squamous Cell Carcinoma
Second
most common - about 200,000 per year
Mostly in older people and fair-skinned people
Highly related to amount of sun-exposure, but also other carcinogens including
arsenic, certain viruses, tar, fuel oils, radiation
Begins as a precancerous growth - irregular pigment and shape Image
1 and Image
2
Treatment
Removal - surgery
Malignant melanoma
Rarest,
but on rise
Most likely to metastasize
May be fatal if left untreated
Highly related to amount of sun-exposure
Light-complexion, fair hair, light eyes
Severe sunburn before age 20
Family history
Multiple, unusual or congenital moles
Appearance
varies - superficial
spreading, nodular
Map
Treatment
Surgery to remove
Early diagnosis critical
Chemotherapy and radiation may be helpful after metastasis.
To reduce chance of
contracting skin cancer
Stay safe
in the sun
Minimize
sun exposure Image
Wear sunblock and apply well. Image
Viruses
Examples: chicken pox, smallpox, polio, herpes, flu (influenza), colds,
rabies, yellow fever, polio, viral pneumonia, infectious hepatitis, measles,
German measles, viral encephalitis, mononucleosis, mumps, and AIDS
Some
can be prevented with vaccines: smallpox, polio, chicken pox, flu
Immune
responses usually appear too late to prevent disease, but they are important in
preventing reinfection
Interferon
probably responsible for recovery by interacting with receptor sites on
uninfected cells
Implicated
in some cancers, leukemias, autoimmune diseases like
multiple sclerosis, rheumatoid arthritis, diabetes
Ebola hemorrhagic fever (Ebola HF)
Ebola
virus limited to parts of Africa
The
incubation period for Ebola HF ranges from 2 to 21 days.
The
onset of illness is abrupt and is characterized by fever, headache, joint and
muscle aches, sore throat, and weakness, followed by diarrhea, vomiting, and
stomach pain. A rash,
red eyes, hiccups and internal and external bleeding may be seen in some
patients.
Mortality
is high, reaching 90%. Ebola
medical team
Smallpox
mortality rate of 20 to 50
percent.
This
disease is spread by inhalation of air droplets or aerosols.
Stages
- Fever and rash appeared after an average incubation period of 12 days, with a
progression to typical vesicular and pustular lesions over 1 to 2
weeks.
smallpox vs chicken pox - image 1
and image
2.
vaccination
Bacteria
Examples:
cholera,
leprosy,
tetanus, anthrax,
Lyme
disease, bacterial pneumonia, whooping cough, syphilis, gonorrhea, bubonic
plague, (life cycle),
typhus, food poisoning.
Many
bacterial diseases spread through food or water.
Insect vectors spread diseases like typhus
Tuberculosis, known historically as consumption or wasting disease. Image
Eight million new cases each year, three million deaths. Map
Graph
(World TB incidence. Cases per 100,000; Red = >300, orange =
200-300; yellow = 100-200; green 50-100 and grey <50. Data from WHO, 2006.)
Leading
cause of death from a single infectious
agent
Eradication programs dismantled in U.S. in 1980's
Experiencing a dramatic resurgence
of the disease
Associated with prevalence of HIV
The
disease is characterized by the development of granulomas
(granular tumors) in the infected tissues.
TB is
highly contagious and
can lie dormant, apparently inside host cells where it is not easily detected,
for up to 40 years.
In 1947, the first antituberculous drugs were
discovered.
Detection:
skin
test (Tine test)
Drug
resistance
Anthrax
Caused
by Bacillus
anthracis, a bacterium that forms spores.
There
are three types of anthrax:
* skin
(cutaneous): infection
and result:
more results
* lungs
(inhalation)
* digestive
(gastrointestinal)
Anthrax
is not known to spread from one person to another.
Antibiotics
are used to treat all three types of anthrax.
Vaccination.
There is a vaccine to prevent anthrax, but it is not yet available for the
general public.
Diseases caused by Protists
Examples:
Giardia (Image) (life
cycle)
Trichomonas vaginalis
(Image)
Trypanosoma
spp. cause sleeping sickness (Image)
Plasmodium
spp. cause malaria (Life cycle)
Transmission often by vectors
African sleeping
sickness
Caused by trypanosomes (Image)
Life cycle
of the trypanosome that causes African sleeping sickness.
Vector: Tsetse fly
Generalized pain, weakness, cramps and swelling of neck lymph nodes (Winterbottom sign). Parasites
invade all organs of the body including heart and CNS. The latter leads to apathy,
mental dullness, tremors, convulsions and sleepiness, coma. There is rapid
weight loss and death a few months later from malnutrition, heart failure,
pneumonia or a parasitic infection. Map of
occurrence area.
Host reactions to the trypanosome
parasite
The number of parasites in blood
shows waves as the immune system partially overcomes the infection.
This escape from the immune response depends upon the ability to express a new surface antigen.
Treat
cattle with pesticide.
American trypanosomiasis - life
cycle Map
Malaria (Life cycle)
characterized by
fever, chills, and anemia.
Malaria
is caused by a parasite that is transmitted from one human to another by the
bite of infected Anopheles
mosquitoes. In humans, the parasites migrate to the liver where they mature and
release another form. These enter the bloodstream and infect the red blood
cells.
The
parasites multiply inside the red blood
cells, which then rupture within 48 to 72 hours, infecting more red blood
cells. The first symptoms usually occur 10 days to 4 weeks after infection,
though they can appear as early as 8 days or as long as a year later. Then the
symptoms occur in cycles of 48 to 72 hours.
The
majority of symptoms are caused by the massive release into the bloodstream,
the anemia resulting from the destruction of the red blood cells, and the
problems caused by large amounts of free hemoglobin released into the
circulation after red blood cells rupture.
* Sequential chills, fever,
and sweating
* Headache
* Nausea and vomiting
* Muscle pain
* Anemia
* Stools, bloody
* Jaundice
* Convulsion
* Coma
In
some areas of the world, mosquitoes that carry malaria have developed
resistance to insecticides, while the parasites have developed resistance to
antibiotics. Map
of malaria vectors and map
where malaria is currently found.
Falciparum malaria, one of
four different types of malaria, affects a greater proportion of the red blood
cells than the other types and is much more serious. It can be fatal within a
few hours of the first symptoms.
Anti-malarial
drugs can be prescribed to people traveling to areas where malaria is
prevalent, but must be started 2 weeks prior. Prevention
You can
find information on all diseases at the Center for Disease Control: http://www.cdc.gov/health/diseases.htm
