EPI 390 Lecture 10Outline of Last Lecture I. Epiphyseal Plate and bone growtha. Hydroxyapatite bone tissueb. RicketsII. Osteoporosis model a. Effect of puberty on bone healthb. Effect of Menopause on bone healthc. Growth curvesd. Common sites for fragility fracturesIII. Comparing bone cellsIV. Osteoporosis preventionV. Pott’s diseaseOutline of Current Lecture Guest Lecturer: Dr. PanethI. Properties of Smallpox virusII. Transmission and ProgressionIII. History of SmallpoxIV. Attempts at Preventiona. Variolationb. VaccinationV. Smallpox in the 20th CenturyVI. Eradication CampaignVII. Recent pox concernsCurrent LectureI. Properties of Smallpox virusa. Smallpox virus is a double-stranded DNA virus of the orthopox familyb. Largest known virusc. Many related animal pox viruses, though smallpox itself is a human only disease with no animal vectorsi. Chicken pox is a herpes virus, not relatedd. It’s a stable virus; it can retain some virility outside hoste. Highly contagiousf. Incubation period is 7-17 daysThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.II. Transmission and Progressiona. Person to person via respiratory route (inhalation of droplets from coughing/talking, more rarely via aerosol)b. Direct contact is less common (w/ infected fluids or items)c. No transmission from animal reservoir (only spread from another smallpox case)i. The Prodrome phase (fever, no rash) is less contagiousii. Most contagious with rash, remain contagious until last scab is goned. First 7-17 days feel slightly ill. 2-3 days of spike in illness and then lesions start. Lesions can last a couple weeks, and cover everything (unlike chicken pox which are more mild)e. Cases of smallpox had to be reported right away – this was when we were trying to eradicate it. Public was taught to recognize symptoms so could report themf. Day 5 of symptoms (not incubation) fever starts, lesions everywhereg. Convergence of lesions (combining of 2 lesions) is a bad prognosis. Confluent smallpox has very high mortality i. 70% mortality in sheet mortality – when almost all lesions are confluent. ii. Hemorrhagic smallpox (bleeding to lesions) is almost 100% fataliii. Variola Minor – a mild strain of smallpoxh. Distinguishing feature of smallpox vs. Chicken pox: smallpox is found in the periphery, limbs, and face. Chicken pox tends to stay concentrated in chest.III. History of Smallpoxa. Long history of smallpox; it first appeared in Northeastern Africa around 10,000BCb. Many cultures had gods to worship for protection from smallpox. c. Use of smallpox in warfare – cultures that hadn’t been exposed to the disease didn’t have immunity so it was very devastating to the population. i. Smallpox was typically devastating to everyone, but other diseases like whooping cough were also a problem for those without exposure/immunity.IV. Attempts at Preventiona. Variolationi. Realized early that if you had smallpox once then wouldn’t get it again so tried to create artificial, mild cases of smallpox so that you would avoid a serious case. Would use various parts of smallpox material from infected (i.e. ground up scabs, or puss, etc.) and would administer in various waysii. China ground scabs into powder and inhaled it. India applied material to skin. Turkey dipped string into pus then would cut open arm and slide string through cut. This created “mild” case; 1-2% fatality still. iii. Lady Mary Wortley Montague tested Turkish method in London/England. Tested it on convicted murderers set to be executed. They could either beexecuted or be inoculated. If they chose inoculation and survived, they’d be pardoned. All were pardoned.b. Vaccinationi. Late 18th century: vaccination introduced1. Edward Jenner – noticed that milkmaids didn’t get smallpox (milkmaid complexion was prized b/c never had smallpox scarring). They got cowpox, a mild infection of hands gotten from cow udders. 2. Thought this might be a better way to prevent smallpox with less mortality; people vaccinated with cowpox didn’t get smallpox. 3. Cowpox: mild lesions on the hand; the infected person might get alittle ill/feverish. a. The disease is not lethal. (first indication of attenuated viruses)4. Vaccination: would create one lesion. Take a little from lesion to create lesion on next person. Would vaccinate one person to another (young person or child). Got vaccination to US by spreading lesion one person at a time; by the time they reached the US from England, the last person had been vaccinated and stillhad a lesion that could be used in US.5. Occasional outbreaks even after compulsory vaccination due to the fact that some people still avoid getting vaccinated. ii. Vaccination side effects1. Reaction at primary vaccination site – get a small pustule that last for about 2 weeks before drying up and scabbing over. Leaves scar.2. Scar was important in determining who’d actually been vaccinated. No scar might mean revaccination.3. Could NOT scratch pustule. If you scratched then rubbed your eyes, could get ocular vaccinia (non-lethal eye infection that is nasty)4. Vaccinia – mild infection over body and bad lesion at injection site5. Children with suppressed immune system could get very serious, life threatening vaccinia necrosum. 6. Those with eczema would have bad reactions in eczemic skin7. Last US case was 1948, 1966 risk of dying from vaccine was higher than risk of generating disease so stopped compulsory vaccination(only had to get it if traveling to pandemic place)8. Islands easiest place to eradicateV. Smallpox in the 20th Centurya. Imported outbreaks – travellers could be infected in countries where the virus hadn’t been eradicated and then they would bring the disease back home and infect othersi. i.e. the Engineer who went to Pakistan: vent ducts spread his disease throughout hospital. Shows how communicable smallpox was (one visitorinfected after only 15 min in hospital and went nowhere near engineer’s room)b. Fatality of smallpox from overwhelming virenia/infection (no particular organ failure, just host defense symptoms overwhelmed and worn down)VI. Eradication Campaigna. 13 yr campaign by WHO DA Henderson; very dynamic, invested team from all over world. Very enthusiastic about campaign, which was partly responsible for success. b. Another key leader: Henry Bedson (prof of virology at U of Birmingham. His father