Bios30401 Lecture 19 PDF

Person to person diseases I Bios30401 Nov 25, 2024 Diseases-know cause, unique symptoms, treatments, vaccine or not. Exam 3 average was 88. pvaughan.youcanbook.me by Dec 6 if you want to look at your exam.  Airborne pathogens an...

Person to person diseases I Bios30401 Nov 25, 2024 Diseases-know cause, unique symptoms, treatments, vaccine or not. Exam 3 average was 88. pvaughan.youcanbook.me by Dec 6 if you want to look at your exam.  Airborne pathogens and the respiratory system FYI Each droplet 10 mm, 1-2 organisms 10,000-100,000/sneeze. Gram + and viruses survive best Also expelled while talking and coughing  Streptococcal diseases S. pyogenes Encapsulated S. pneumoniae b hemolytic Over 60 strains Strep throat, impetigo, rheumatic fever, scarlet fever, strep TSS, necrotizing S. pneumoniae Encapsulated form pathogenic 90 serotypes Pneumococcal pneumonia- high mortality rate Group A streptococci (GAS, S. pyogenes) virulence factors Lancefield group A (antigen) Surface (fimbriae) M protein helps protect from phagocytosis (antigenic drift and shift and rheumatogenic) Produce hyaluronidase-invasiveness (hyaluronic acid promotes cell-cell contact) Produce streptokinase that dissolves clots and allows further invasion Produce streptolysin O (attacks sterols) and streptolysin S (leukocidin) Superantigen - erythrogenic toxin Superantigens An antigen capable of producing an inappropriately strong immune response Stimulate abnormally high number of T cells (5-25%) Bind to TCRs and MHCs in non-specific manner Can lead to systemic reactions and shock S. pyogenes scarlet fever and streptococcal toxic shock syndrome Indistinguishable from septic shock Strep throat S. pyogenes Severe sore throat Enlarged tonsils Tonsillar exudate Similar symptoms could be due to viral infection Rapid ELISA test Culture on BAP Streptococcus sequelae Incomplete antibiotic treatment or no treatment can lead to sequelae-rheumatic fever, scarlet fever, strep TSS, glomerulonephritis Rheumatic fever – M antigen is similar to heart antigens- autoantibodies form Scarlet fever- superantigens Erysipelas (St. Anthony’s fire) Raised rubbery lesions Very common before antibiotics Post surgery and wounds High mortality Rare now and mortality low Impetigo Contagious skin infection S. pyogenes or S. aureus S. pyogenes can also be a cause of otitis media and mastitis Necrotizing fasciatis (“flesh eating”) Strep Rare strain Affects deep layers of tissue (fascia) Very rapid spread of toxins Surgical removal usually necessary because antibiotics not fast enough and not able to reach sites Strep treatments Penicillin and derivatives Erythromycin if allergic or resistant Other antibiotics Vaccine for S. pneumoniae Given to those at high risk  Diptheria Corynebacterium diptheriae Gram + club shaped rods Cells lodge in throat and tonsils Exotoxin causes tissue destruction Pseudomembrane formation Can block airway Untreated-myocarditis and other organs Treatable and preventable Toxoid vaccine Still >50,000 cases worldwide Treat with antibiotics and antitoxin Diptheria toxin AB exotoxin Blocks protein synthesis Toxoid vaccine is the exotoxin treated with formalin (denatured toxin) Immunogenic Part of (DTaP)  Whooping cough Bordatella pertussis Gram neg. short rod Highly infectious Violent cough many weeks Worldwide 50 million cases, 350,000 deaths/year Antibiotics not very effective Vaccine (DTaP), Tdap Toxoids Booster? Herd immunity needs to be improved FYI- infants get DTaP, everyone else gets Tdap (smaller amounts of diptheria and pertussis The CDC now recommends that all pregnant women receive DTaP (actually Tdap) during the third trimester of every pregnancy. All people who come in contact with infants should get a booster shot at least 2 weeks before spending time with a newborn. Meningitis Bacterial, Viral or other Inflammation of meninges (lining of nervous system) Life threatening (viral is usually less severe) Headache, fever, chills, stiff neck Bacterial meningitis is treated with antibiotics Can be caused by various bacteria Staph, strep, Haemophilus (vaccine) High mortality rate if untreated Menigococcal meningitis and meningococcemia Neisseria meningitidis Gram negative diplococcus May be normal flora Airborne transmission Penicillin, chloramphenicol and broad range cephalosporins –must be started ASAP Meningococcemia or meningococcal septicemia Meningococcal meningitis Nasopharynx to bloodstream Headache, fever, chills, stiff neck-rash later ~ 90 % of population in closed community may be carriers 85% mortality if not treated (antibiotics) 15% mortality if treatment delayed Death can occur in 12-48 hrs If not death-serious disability-amputation Vaccine is available Meningitis B  Progression of Meningococcemia  Tuberculosis Mycobacterium tuberculosis Highly contagious Once 1/7 of worldwide deaths Still 14,000 cases/yr U.S., 700 deaths 10 million cases,1.4 million deaths worldwide Inhalation of bacteria into lungs. Infects/lives in macrophages granulomas Destruction of lung tissue TB-cont. Vaccine-attenuated bovine strain Not routine in US Antibiotic isoniazid (inhibits mycolic acid synthesis) and rifampin. Resistance Long term treatment  Hansen’s disease Mycobacterium leprae Infects/lives in macrophages Direct contact or respiratory transmission Not as contagious as TB Incubation can be years 750,000 new cases/yr worldwide Treat with antibiotics No vaccine Airborne Viral Diseases-MMR Measles (rubeola) 20 million cases/yr worldwide Extremely contagious Complications (relatively rare) Inner ear infections, pneumonia*, encephalomyelitis* >100,000 deaths/yr worldwide Mumps Complications (rare) Sterility, encephalitis Rubella (German measles) Complications Teratogen MMR vaccine (attenuated viruses) Airborne Viral Diseases-Chickenpox Varicella zoster virus Herpes virus Latency in nerve cells- can lead to Shingles Highly contagious Airborne droplets and fomites Systemic rash More serious disease in non-immune adults (complications - pneumonia) Immunization 1994 Attenuated virus Airborne Viral Diseases-Colds/SARS/Influenza Colds most common infectious disease Cold-usually rhinovirus (115 serotypes), also corona, adeno and others Self limiting Etiology too complex for vaccine development New potential anti-rhinovirus drugs  SARS Severe Acute Respiratory Syndrome Coronavirus-often led to pneumonia (SARS-CoV) First reports in Asia-Feb, 2003 2 dozen countries ~8100 infected-774 died, none in U.S. Spread by close contact No new cases (naturally caused) since July, 2003 2012 MERS-also coronavirus Covid19-SARS-CoV2 ~88% overall identical to SARS 75% identical in spike protein Both enter at ACE-2 receptor Influenza Transmitted thru droplets Fever, chills, fatigue, headache, achiness, malaise lasting 3-7 days. (Can be several weeks before complete recovery) 3-5 million cases and 250,000-500,000 deaths/year worldwide Primary disease is self limiting Immune to that strain Complications from secondary infections Bacterial pneumonia  Influenza RNA virus Influenza A, B and C Influenza A most important to humans Virus has segmented genome More than one strain infecting a cell can lead to re-assortment of DNA and development of new strains  Influenza A virus Antigenic drift Minor changes in surface proteins (point mutations) Can lead to epidemics Antigenic shift Re-assortment of viral genes leading to new strains Major changes in antigenic proteins H and N (hemagglutinin and neuraminidase) Can lead to pandemics  1918 Influenza pandemic The Spanish Flu I had a little bird, Its name was Enza. I opened the window, And in-flu-enza “Spanish” flu but probably started in US Kansas boot camps Spring 1918 Lasted thru 1920 Spread influenced by WWI Travel Armistice day celebrations 230 million deaths worldwide, 50% of population infected Several million Americans. 30X more than killed in war Most deadly for those 20-40 1918 Influenza pandemic Public Health Obey the laws And wear the gauze Protect your jaws From Septic Paws No social events No sales Funerals 15 min Shortages Morticians, gravediggers, coffins Health care workers  9/26/18 “Have you read about the Spanish influenza epidemic? It was everywhere in Boston and I’m sure it will be in Albany soon. It seems so strange ㅡ this summer we’ve been studying about how skilled scientists have become in controlling disease then this new one comes along and they can do nothing”. 10/14/18“I’d say we have the Influenza in Albany. They sent all the older nurses to the influenza wards and left the rest of the hospital up to us probationers”. 10/21/18 “Two of the girls from the Camp have died ㅡ one in New York City and one in Philadelphia. One of the girls from Boston City Hospital wrote that seven nurses and several doctors there had been taken”. Why was “Spanish” flu so virulent? Virus harvested from frozen bodies in arctic Virus sequenced H1N1 strain Both Asian flu and Spanish flu indicate avian and human strains mixing in swine “Cytokine storm” Overreaction of a healthy immune system Age group of victims Superantigen response Bird flu (H5N1), hantavirus, and SARS deaths also linked to cytokine storm  Cytokine storm >150 mediators released Usually cytokine feedback is kept in check but for some reason uncontrolled Happens when exposed to a new/pathogenic invader Not well understood Flu treatment At end of each season-surveillance of current strains in 101 countries Polyvalent vaccine (usually against 3 strains) Has prevented epidemics but not perfect (2007-2008) Strain specific and lasts a couple of years Flu treatment-shorten duration Amantadine, Rimantadine (Flumadine) inhibit viral replication Oseltamavir (Tamiflu) and zanavir (Relenza) prevent viral release  Seasonal flu vaccines 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 flu shot is approved for use in people older than 6 months, including healthy people and people with chronic medical conditions. 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. http://www.cdc.gov/Flu/protect/keyfacts.htm Influenza vaccine Before 2009, each seasonal influenza vaccine contained three influenza viruses-one A (H3N2) virus, one regular seasonal A (H1N1) virus (not the 2009 H1N1 virus), and one B virus (each requires 1 egg). 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. Swine flu 2009 (novel H1N1) US April 2009 Sequences from five different flu viruses: North American swine influenza, North American avian influenza, Human influenza, and two swine influenza viruses typically found in Asia and Europe. Re-assortment probably occurred in Mexican swine Spread very quickly to become pandemic Luckily, this virus had a relatively low mortality rate BUT… 2009 H1N1 “Study estimates 2009 pandemic deaths at up to 203,000” Nov 26, 2013 PLoS Medicine "We also found that the mortality burden of this pandemic fell most heavily on younger people and those living in certain parts of the Americas." Direct contact diseases Staphylococcal diseases S. aureus Can be normal flora Boils, pimples, impetigo Pyogenic Pneumonia, carditis, meningitis, TSS, scalded skin, food poisoning MRSA S. aureus virulence factors 4 hemolysins – b hemolytic Coagulase Fibrin clotting “protection” of infection Leukocidin Superantigens TSS toxin Exfoliating toxin A and B Enterotoxins A-E (food poisoning) Staph aureus skin infections Scalded skin syndrome Certain strains that produce a particular toxin that blisters the skin Usually< 5 years old Treat with IV antibiotics  Staph aureus skin infections Sty Folliculitis at eyelid  Staph aureus skin infections Furuncle (Boil) Single hair follicle Deeper, wider nodule Staph aureus skin infections Carbuncle More than one follicle Treatment for Staph skin infections varies Nothing Antibacterial ointment Moist heat Surgical drainage MRSA Methicillin resistant S. aureus Also additional virulence factors Infects like any other staph Resists antibiotic treatment Most commonly infects open cuts or abrasions MRSA prevention and treatment (FYI) Keep wounds covered Put barrier between you and shared equipment Wash thoroughly/shower after workouts with common equipment Any skin infection that gets really inflamed-see a doctor MD will drain and clear dead tissue (debridement) http://www.cdc.gov/mrsa/index.html MRSA At least 100,000 invasive MRSA infections/year (15% not associated with hospitals) Treatment-Vancomycin (VISA and VRSA) New antibiotics Phage therapy Maggot therapy