APES Infectious Diseases (viral) - Shope

Infectious Diseases – major / historically significant / common / communicable (transmissible) disease

VIRAL



o HIV / AIDS
• number 2 epidemic disease
• can lie dormant for (long) time before becoming active


o Hepatitis (A, B, C, D, E)
• A – minor, relatively common… especially in children
• B & C – very serious
• D – very rare (often mutation of B or C)
• E – almost non-existent (has never been a case in the US)
• spread by… physical contact (with the exception of A: spread by ingestion… dirty food, putting dirty hands in mouth, etc.)


o smallpox
• now “extinct” (aside from some in a fridge in Atlanta, Moscow)
• transmitted by airborne virus
• used in combat/war
• officially announced that it was gone – 1980
• first disease for which a vaccine was developed…

o Edward Jenner
• British physician in the late 1700s
• traveled country healing people
• noticed that most girls (milkmaids) didn’t have smallpox
• they had contracted cowpox and developed immunity
• meanwhile… inoculation (smallpox: prick skin = immune?)
• Jenner heard about this
• took scrape of smallpox
• heated (weakened) sample then injected into healthy person
• 1st vaccine – 1790
• even vaccinated his own son
• “credited with saving more people than any other in history” (i)


o herpes
• about 8 strains known… HHV = “human herpes virus”
• is a retrovirus: viral DNA attaches to host DNA and becomes part of the genetic make-up of host
• HHV-1 – cold… cold sores = excess protein produced; permanent
• HHV-2 – genital herpes
• HHV-3 – chicken pox
• HHV-4 – Epstein-Barr (mononucleosis, “mono”, “kissing disease”)
• HHV-5, HHV-6, HHV-7 – cause rashes


o rabies
• one of the oldest known diseases
• no cure
• only preventative treatment soon after bite
• if not pretreated… most likely fatal: only one known survivor after the fact (and he had brain damage)


o polio
• mostly gone… few/none in the US in the last 40-50 years
• making a comeback
• devastating in US in 1940s/1950s
• nerve disease
• kills nerves “instantly” (within hours… go to bed fine, wake up paralyzed)
• ex.: FDR
• mostly children… killing or crippling
• Jonas Salk created plan to fight polio – completely “kill” (destroy all DNA) of virus before injection, not just weakening it
• still must be immunized before entering school


o cold / rhinovirus
• over 300 types
• can’t get the same type more than once
• no cure


o influenza
• zoonotic disease (we get it from animals)
• differs from year to year, depending on animal of origin
• most start in China/Asia
• current: avian flu… not yet airborne


o pneumonia
• can be bacterial or viral
• #1 killer of… people with immunological diseases (ex. AIDS), people with cancer, older people


o measles, rubella, mumps
• vaccine necessary before entering school: “MMR”
• rubella = “German measles”… mostly dangerous for pregnant women


o dengue – hemorrhagic fever
• causes bleeding… sometimes even through eyes
• very deadly
• 2 strains: 1 causes sickness, other immediately causes death


o Ebola
• causes bleeding
• very deadly
• has developed 5th strain
• not yet airborne
• mostly Africa (Zaire)


o yellow fever
• transferred via mosquito
• big problem in Central America
• vaccine was created so workers could build Panama Canal