Microbiology Final Exam PDF

# Microbiology Final Exam - **Size of airborne pathogens** - Droplet size: 10mm - Organisms in a droplet: 1-2 - Droplets in a sneeze: 10,000-100,000 - Droplets expelled: Talking and coughing - **Types of pathogens that survive in the air:** Gram-positive bacteria and viruses - **Cla...

# Microbiology Final Exam - **Size of airborne pathogens** - Droplet size: 10mm - Organisms in a droplet: 1-2 - Droplets in a sneeze: 10,000-100,000 - Droplets expelled: Talking and coughing - **Types of pathogens that survive in the air:** Gram-positive bacteria and viruses - **Classes of Streptococcal Diseases:** - 1. *S. pyogenes* - 2. *S. pneumoniae* - Hemolysis of _S. pyogenes_: Beta hemolytic - full cell lysis - **_S. pyogenes_ strains:** Over 60 - **Diseases caused by _S. pyogenes_** - 1. Strep throat - 2. Impetigo - 3. Rheumatic fever - 4. Strep TSS - 5. Scarlet fever - 6. Necrotizing - **Pathogenic _S. pneumoniae_:** Encapsulated form - **Serotypes of _S. pneumoniae_:** 90 - **Group A Streptococci:** GAS - _S. pyogenes_ - **Virulence Factors of GAS:** - 1. Lancefield group A - 2. Surface M protein - 3. Hyaluronidase production - 4. Streptokinase production - 5. Streptyloysin O and S production - 6. Superantigen - **Virulence Factor for _S. pyogenes_:** Surface antigen - **Virulence Factor for _S. pyogenes_:** Fimbriae (hairlike appendage) - helps protect from phagocytosis - **Antigenic Drift:** Small changes to antigen - **Antigenic Shift:** Major change to antigen - **Rheumatogenic:** Causes immune inflammation - **Hyaluronidase:** _S. pyogenes_ virulence factor - invasiveness through promotion of cell-cell contact - **Streptokinase:** _S. pyogenes_ virulence factor - dissolves blood clots and allows for further invasion - **Streptolysin O and S:** _S. pyogenes_ virulence factor - O: attacks sterols - S: leukocidin (pore forming toxin) - both attack cell membranes - **Erythrogenic Toxin:** Exotoxin capable of producing superantigen - **Superantigens:** Exotoxins excreted by GAS - capable of producing an inappropriately strong immune response - stimulates 25% T cell activity - response is large and non-specific - **Superantigen Immune Response Mechanism:** Bind to TCRs and MHCs in a non-specific manner, stimulating a high percentage (25%) of T cells - **Superantigen Effects:** Systemic reactions and shock - **Strep Throat:** Cause: _S. pyogenes_ - Unique symptoms: sore throat, enlarged tonsils, tonsillar exudate - Treatments: antibiotics - Vaccine: No - Symptoms could be due to a viral infection - **Strep Tests:** Rapid ELISA test (enzyme) - culture on BAP (blood agar plate) - hemolysis test - **Streptococcus Sequelae:** Sequelae: condition which is the result of previous infection/injury - Incomplete antibiotic treatment/ no treatment: can lead to - 1. Rheumatic fever - 2. Scarlet fever - 3. Strep TSS - 4. Glomerulonephritis: kidney inflammation/damage - **Rhematic Fever:** M antigen is similar to heart antigens - **Scarlet Fever:** Superantigens form during _streptococcus_ infection - **Erysipelas:** Cause: _S. pyogenes_ - Unique symptoms: raised, rubbery lesions, common before the invention of antibiotics - Treatments: antibiotics - Vaccine: No - **Impetigo:** Cause: _S. pyogenes_, _S. aureus_ - Unique symptoms: skin infection - Treatments: antibiotics - Vaccine: No - *S. pyogenes_ also causes otitis media and mastitis in new moms - **Necrotizing Fasciitis:** Cause: _S. pyogenes_ - Unique symptoms: deep layers of tissue are infected or eaten - Treatments: surgical removal necessary - Antibiotics don't reach fast or deep enough - Vaccine: No - **Strep Treatments:** - 1. Penicillin and derivatives - 2. Erythromycin if allergic or resistant - 3. Other antibiotics - 4. Vaccine for _S. pneumoniae_ (given to high-risk individuals) - **Diptheria:** Cause: _Corynebacterium diptheriae_ - Unique symptoms: pseudomembrane formation, myocarditis - Treatments: toxoid vaccine, antibiotics, antitoxin - Vaccine: Yes <start_of_image>- **_Corynebacterium diptheriae_:** Gram-positive club-shaped rods - **Diptheria Mechanism:** _Corynebacterium diptheriae_ causes infected cells to lodge in the throat and tonsils - **Diptheria Exotoxin:** Causes tissue destruction, formation of pseudomembrane which blocks airways - **Diptheria Vaccine:** Toxoid (inactivated toxin) - exotoxin treated with formalin (denatured toxin) - immunogenic - provokes host immune response - part of DTaP - **Diptheria Toxin:** AB exotoxin (protein) - blocks protein synthesis - **Whooping Cough:** Cause: _Bordetella pertussis_ - Unique symptoms: highly infectious, violent cough for many weeks - Treatments: antibiotic not very effective, DTaP, Tdap vaccines - Vaccine: Yes - **DTaP vs. Tdap:** Infants get DTaP and everyone else gets Tdap - DTaP has a portion of pertussis, only parts - Tdap has toxoid vaccines and booster required - **_Bordetella pertussis_:** Gram-negative short rods - **Whooping Cough Prevalence:** 50 million cases worldwide, 350,000 deaths per year, widespread - **Meningitis:** Cause: bacterial, viral, or other - Unique symptoms: headache, fever, chills, stiff neck - Treatments: bacterial uses antibiotics - Vaccine: yes - **Meningococcal Meningitis and Meningococcemia:** Cause: _Neisseria meningitidis_ - Unique symptoms: airborne transmission, general meningitis symptoms, rash/tissue death - Treatments: penicillin, chloramphenicol, and broad-range cephalosporins (start immediately) - Vaccine: yes (for meningococcal meningitis) - Meningococcemia involves infection of the blood as well - **Meningococcal Meningitis:** Nasopharynx to bloodstream - Rash forms in addition to other symptoms - Up to 90% of the population in a closed community may be carriers - Very high mortality if untreated or treatment delayed - Vaccine available - **Tuberculosis:** Cause: _Mycobacterium tuberculosis_ - Unique symptoms: destruction of lung tissue, highly contagious - Treatments: vaccine, antibiotics (isoniazid and rifampin) - Vaccine: Yes - **Tuberculosis Vaccine Type:** Attenuated bovine strain - **Tuberculosis Infection Mechanism:** Inhalation of bacteria into lungs - Infects/lives in macrophages - Formation of granulomas leading to the destruction of lung tissue - **Hansen's Disease:** Cause: _Mycobacterium leprae_ - Unique symptoms: rash and boils - Treatments: antibiotics - Vaccine: No - Infects/lives in macrophages - Direct contact or respiratory transmission - Incubation period: can be years - **MMR:** Airborne viral diseases - 1. Measles (rubeola) - 2. Mumps - 3. Rubella (German measles) - **Measles:** Airborne viral diseases - Extremely contagious - Complications: inner ear infections, pneumonia, encephalomyelitis - **Mumps:** Symptom: salivary gland swelling - Type: airborne viral disease - Complications: sterility, encephalitis - **Rubella:** Name: German measles - Type: airborne viral disease - Complications: teratogen (substance that inhibits neurological function) - **MMR Vaccine Type:** Attenuated virus - live but reduced virulence - **Chickenpox:** Cause: _Varicella zoster virus_ - Unique symptoms: systemic rash - Vaccine: yes - **_Varicella zoster virus_:** Herpes virus - Latency in nerve cells can lead to shingles - **Chickenpox Spread:** Airborne droplets and fomites - **Chickenpox Vaccine Type:** Attenuated virus - live with reduced virulence - **Colds/SARS/Influenza:** Airborne viral diseases - Colds: most common infectious disease - usually rhinovirus - etiology too complex for vaccine development - new potential for anti-rhinovirus drugs - SARS - Name: Severe acute respiratory syndrome - Epidemic: Asia - February 2003 - Mode of infection: 2 dozen countries - spread through close contact - Influenza - Transmission: transmitted through droplets - Symptoms: fever, chills, fatigue, headache, malaise - Treatment: primary disease is self-limiting (resolves without treatment) - **Common Cold/Flu Symptoms:** - 1. Fever: rare in cold, common in flu - 2. Headache: rare in cold, common in flu - 3. Malaise: slight in cold, common and severe in flu - 4. Nasal discharge: common and high in cold, less common in flu - 5. Sore throat: common in a cold, less common in flu - 6. Vomiting or diarrhea: rare in a cold, common in children with the flu - **Influenza Virus:** RNA virus - types: A, B, and C - **Influenza A Virus:** Most important to humans - virus has segmented genome - reassortment of DNA and development of new pathogenic strains can occur - causes seasonal endemics in humans - subject to antigenic drift and shift - can lead to pandemics - major changes in antigenic proteins H and N can lead to pandemics - 8 segment genome - **Why was Spanish flu so virulent?:** avian and human strains mixed in swine - **Cytokine Storm:** Overreaction of a healthy immune system - more than 150 mediators released - occurs when exposed to a new/pathogenic invader - not well understood - **Flu Mitigation Strategies:** Surveillance of current strains at the end of each season - creation of polyvalent vaccine - **Direct Contact Diseases:** - Staphylococcal diseases - can be normal flora - *S. aureus* - Boils - Pimples - Impetigo - **_S. aureus_ Virulence Factors:** - 1. 4 hemolysins (beta hemolytic) - 2. Coagulase - 3. Leukocidin - 4. Superantigens - **Coagulase:** Fibrin clotting - protection of infection - _S. aureus_ virulence factor - **Superantigens in _S. aureus_:** Virulence factor - 1. TSS toxin - 2. Exfoliating toxin A and B - 3. Enterotoxins A-E (food poisoning) - **Scalded Skin Syndrome:** Cause: _S. aureus_ - Unique symptoms: toxin blisters skin - Treatments: IV antibiotics - Vaccine: No - **Sty:** Cause: _S. aureus_ - Unique symptoms: folliculitis at eyelid - Treatments: antibacterial ointment, moist heat, drainage - Vaccine: No - **Furuncle:** Cause: _S. aureus_ - Unique symptoms: single hair follicle inflammation - Treatments: antibacterial ointment, moist heat, drainage - Vaccine: No - **MRSA:** Cause: methicillin-resistant _S. aureus_ - Unique symptoms: open cuts/abrasions - Treatments: resists antibiotic treatment, drainage and clearing dead tissue, vancomycin, phage therapy - Vaccine: No - **Hepatitis:** Cause: viral disease - Unique symptoms: jaundice, hepatomegaly, cirrhosis - Treatments: gammaglobulins, antiviral, interferon for Hep C - Vaccine: for A and B - **Hep A, B, C:** - Type of virus: - Hep A: RNA - Hep B: DNA - Hep C: RNA - Transmission: - Hep A: Fecal-oral - Hep B: Blood - Hep C: Blood - Severity: - Hep A: Mild - Hep B: Can be severe - Hep C: Can be severe - Carrier: - Hep A: No - Hep B: Yes - Hep C: Yes - Chronic liver disease: - Hep A; No - Hep B: Yes - Hep C: Yes - Vaccine: - Hep A: Yes - Hep B: Yes - Hep C: No - **Mononucleosis:** Cause: Epstein-Barr virus - Unique symptoms: sore throat, tiredness - Treatments: rest (self-limiting), no contact sports (spleen enlargement) - Vaccine: No - **Mononucleosis Mechanism of Infection:** Epstein-Barr spreads through saliva - can incubate up to 8 weeks - virus replicates in B cells and epithelial cells of the pharynx - 50% of WBCs are lymphocytes - **Mono Test:** Monospot test (agglutination test for Ab), rapid - **Burkitt's Lymphoma:** Extremely rate in the US - linked with HIV and Epstein-Barr virus infection (mono) - other factors: chronic malaria or immunicompromisation - **Warts:** Cause: human papilloma virus (100 strains) - Genital: sexually transmitted, vaccine exists - Dermal: through abrasions - **Gonorrhea:** "The clap" - Cause: _Neisseria gonorrhea_ - Unique symptoms: drip of pus - Treatments: antibiotics - Vaccine: No - **Gonorrhea Complications:** Pelvic inflammatory disease - inflammation of the uterus - can lead to sterility - **Gonorrhea Transmission Mechanism:** Attaches to epithelial cells of the GU tract and sperm - multiplies in leukocytes - Women often asymptomatic - **_Neisseria gonorrhea_:** Gram-negative diplococci - **Non-gonococcal Urethritis:** Gonorrhea-like STC, often coincident with gonorrhea - No diplococci - caused by _chlamydia_ - tiny, spherical intracellular bacteria - watery discharge - no immunity - antibiotics - **Syphilis:** "The pox" - Cause: _Treponema pallidum_ - Unique symptoms: chancres on lips, genitals (hard, painless lesions), rashes, heart and nervous system problems - Treatments: antibiotics - Recovery does not confer immunity - Vaccine: No - Spread: body fluids (including saliva) - Human only reservoir - **_Treponema pallidum_:** Bacterial spirochete - **Stages of Syphilis:** - 1. Primary phase: 4-6 weeks, chancres on genitals and lips - 2. Primary latent phase - 3. Secondary state: can last years, rash on palms and soles, pustular rashes on tongue, cheek, gums - 4. Secondary latent phase: sometimes ends here - 5. Tertiary phase: permanent damage to cardiovascular and nervous systems, granulomas form in the nervous system and skin - **Congenital Syphilis:** Treponemas cross placenta - Hutchinson's teeth - perforated palate - saber shins - saddle nose - **Other Bacterial STDs:** - 1. Chancroid: painful lesions that bleed, common in tropical climates - 2. _Ureaplasma_ urethritis - 3. _Mycoplasma_ urethritis - **Herpes:** Cause: viral - Unique symptoms: HSV-1: cold sores, occasionally genital - HSV-2: mostly genital - Treatments: antivirals - Vaccine: No - Infected during birth - C-section prevents - **Neonatal Herpes:** Infected during birth - C-section prevents - **AIDS:** Cause: HIV - human immunodeficiency virus - 99% due to HIV-1 (HIV-2 causes milder disease) - Treatment: antivirals - Vaccine: no - Case definition: test positive for HIV and have a CD4 T cell count of <200/mm3 of whole blood or (very low) - A CD4 T cell count of >200/mm3 and the presence of opportunistic infections - Opportunistic infections: hallmark of AIDS - fingal, parasitic, bacterial, and viral infections - HHV-8: human herpes virus - often present in AIDS patients - **HIV Virus:** Type: Retrovirus - Genetic material type: RNA - Components: 2 strands of identical RNA - genome encodes just a few enzymes and REVERSE TRANCRIPTASE - surface proteins and envelope - **HIV Pathogenesis:** - 1. Initial infection of macrophage - 2. Interaction between gp120 (on surface of infected cell) of virus and CD4 and CCR5 co-receptor (present on T helper cells) - 3. After attachment, fusion of envelope, insertion of nucleocapsid with virus particles - 4. Uncoating of RNA - 5. RT in cytoplasm - 6. dsDNA to nucleus - provirus integrates with host DNA in latent state - 7. New virus made and released - **HIV Diagnosis:** ELISA screen for antibodies - PCR detects viral RNA - viral load - used in monitoring the effectiveness of treatments - **AIDS Treatment:** Reduction of viral load - HAART (highly active antiretroviral therapy) - not a cure but helps - **Azidothymidine (AZT):** NRTI (nucleoside reverse transcriptase inhibitor) - nucleoside analogs (thymine analog) - prevents DNA replication - anti metabolites - lacks 3' OH group-chain termination - drug resistance within weeks if given alone - "the cocktail" - **NNRTIs (non-nucleoside reverse transcriptase inhibitors):** Interaction with RT protein to block the catalytic site - however, a single mutation leads to resistance - **Protease Inhibitors:** Peptide analogs - bind to HIV protease which is required for viral protein processing and virus maturation - **6 Types of AIDS Antiretroviral Drugs:** - 1. Nucleoside RT inhibitors - 2. Non-nucleoside RT inhibitors - 3. Protease inhibitors - 4. Fusion inhibitors - 5. Integrase inhibitors - 6. Entry inhibitors - **Fusion Inhibitors:** Bind to viral surface protein (gp41) - inhibits fusion of envelope to CD4 host cell membrane - given to patients who are resistant to other drugs - **Integrase Inhibitors:** Block the action of integrase - enzyme that integrates viral dsDNA into host genome - blocks provirus formation - **Entry Inhibitors:** CCR5 inhibitors - required for initial viral infection between HIV virion and the target cell - **HAART (highly active antiretroviral therapy):** 1 protease inhibitor or NNRTI + 2 NRTI - resistance to 3 drugs simultaneously is much less likely - monitor viral load by RT-PCR - want non-detectable viral load (<500 copies HIV/ml blood) - **AIDS Vaccine:** Preventative vaccine - many in trial but no success yet - PrEP: pre-exposure prophylaxis - **Enzootic:** Endemic to certain animal populations - **Epizootic:** Epidemic proportions, potential for human infection increases - **Rabies Reservoir:** Enzootic: raccoons, skunks, coyotes, foxes, bats, occasional domestic animals, but not in the US since we vaccinate - **Rabies Virus Type:** Rhabdovirus - minus sense ssRNA - **Rabies Virus Mechanism of Infection:** Replicates at the site of bite and travels to the central nervous system - if untreated leads to death - present in saliva - **Rabies Symptoms:** Hydrophobia (fear of swallowing), foaming at the mouth - **Rabies Incubation Period:** In dogs: 10-14 days - In humans: months - **Rabies Diagnosis:** - 1. Immunofluorescence of tissue - looking for Negri bodies in the brain postmortem - 2. RT-PCR of specimens - **Rabies Treatment:** - 1. Rabies immune globulin: purified anti-rabies antibodies (passive immunity). - 2. Vaccine: inactivated virus causes an immune response, Pasteur invented. - **Rabies Prevention:** - 1. Vaccine for those at high risk - vets, animal control officers. - 2. Vaccination of domestic animals. - 3. Vaccination of wild animals - oral vaccination bait. - **Rabies Vaccine Type:** Inactivated or attenuated virus - **3 Viral Hemorrhagic Fevers:** - 1. Hantavirus - 2. Ebola - 3. Marburg - **Viral Hemorrhagic Fever Effects:** Don't rely on humans for transmission - vascular system is damaged and death usually results from organ damage - **Hantavirus Syndromes:** - 1. Hantavirus pulmonary syndrome (HPS) - 2. Hemorrhagic fever with renal syndrome (HFRS) - caused by different strains - **Hantavirus Pulmonary Syndrome (HPS):** Acute respiratory and cardiac disease - sudden onset fever, muscle pain, thrombocytopenia, leukocytosis, pulmonary capillary leakage - a cytokine storm induced by a superantigen - drowning in your own fluids - result of hantavirus - **Hemorrhagic Fever With Renal Syndrome:** Shock and kidney failure - result of hantavirus - **Hantavirus Transmission:** From rodents through aerosolization of droppings in urine and feces - virus survives a long time in droppings - **Hantavirus Type:** Enveloped minus ssRNA strand - **Hantavirus Host:** Humans are an accidential host - **Tests for HPS:** ELISA for antibody presence - PCR for viral presence - **HPS Treatment:** No cure or vaccine - **Marburg Hemorrhagic Fever Transmission Mode:** Virus infected monkeys (reservoir in bats) - **Ebola Virus Type:** Minus sense RNA virus, filamentous - **Ebola Hemorrhagic Fever Symptoms:** Spread through fluids, fever, diarrhea, vomiting, and bleeding (internal/external) - **Ebola Treatment:** No cure or vaccine - plasma from recovered individuals - **Ebola Reservoir:** Unidentified, but a fruit bat is considered a strong possibility - **Arthropod-Transmitted Bacterial Diseases:** - 1. Rickettsia - 2. Lyme disease - 3. Plague - **Categories of Rickettsial Diseases:** - 1. Typhus - 2. Spotted fever - 3. Ehrlichiosis - **Rickettsial Bacteria:** Small intracellular bacteria, typically phagocytes - can only be grown in cells, very difficult to culture - **Organelle Related to Ricketts:** Mitochondria - **Rickettsial Host and Vector:** Mammalian host, arthropod vectors - **Types of Arthropod Rickettsial Vectors:** - 1. Lice - 2. Fleas - 3. Ticks - **Typhus Bacteria:** _Rickettsia prowazekii_ - **Typhus Regions:** Overcrowded regions, bad sanitation - **Typhus Vector:** Body lice (bite is contaminated with feces), arthropod - **Typhus Incubation Period:** 1-3 weeks - **Typhus Symptoms:** Fever, headache, weakness - rash everywhere, except face, palms, soles - **Typhus Untreated:** Spreads to CNS, lungs, kidneys - **Typhus Treatments:** - 1. Tetracycline - 2. Chloramphenicol - **Rocky Mountain Spotted Fever Bacteria:** _Rickettsia rickettsii_ - **Rocky Mountain Spotted Fever Vector:** Ticks (bite contaminated by feces), arthropod - **Rocky Mountain Spotted Fever Incubation Period:** 3-12 days - **Rocky Mountain Spotted Fever Symptoms:** Fever, severe headache, rash over whole body - **Rocky Mountain Spotted Fever Treatments:** - 1. Tetracycline - 2. Chloramphenicol - **Rocky Mountain Spotted Fever vs. Tyhpoid Treatments:** The same! (tetracycline and chloramphenicol) - **Ehrlichosis Bacteria:** _Ehrlichia_ - **Ehrlichiosis Hosts:** Humans, deer, rodents - **Ehrlichosis Vector:** Ticks - **Ehrlichiosis Symptoms:** Flu-like symptoms, decreased WBC (leukopenia), liver function changes, mild rash - **Lyme Disease Bacteria:** _Borrelia burgdorferi_ - **_Borrelia burgdorferi_ Type:** Lyme disease spirochete - **Lyme Disease Vector:** Ticks - **Lyme Disease Host:** Humans, deer, mice, other rodents - **Lyme Disease Symptoms:** - Acute: headache, backache, chills, fatigue - Bullseye rash: erythema migrans - Chronic: arthritis, neurological symptoms - **Erythema Migrans:** Bullseye rash that grows - associated with Lyme disease - **Chronic Lyme Disease Symptoms:** Neurological deficits can be similar to syphilis - **Lyme Disease Diagnosis:** ELISA, western blot, PCR - **Lyme Disease Prevention:** DEET, tick checks - **Lyme Disease Treatment:** Antibiotics (may need long-term treatment)- no current human vaccine - **Plague Bacteria:** _Yersinia pestis_ - **_Yersinia pestis_ Type:** Gram-negative enteric, capsule - **Plague Body Parts Affected:** Lymph nodes and eventually becomes systemic - **Plague Hosts:** Rodents, humans are accidental - **Plague Vector:** Flea - **Plague Present:** Southwest USA (endemic to wild rodents) - **6 Arthropod-Transmitted Viral Diseases:** - 1. West Nile - 2. Yellow fever - 3. Equine encephalitis - 4. Dengue fever - 5. Chikungunya - 6. Zika - **West Nile Virus Type:** Flavivirus - positive sense ssRNA - **West Nile Vector:** Mosquitos - **West Nile Host:** Humans, horses, birds - **West Nile Always Present:** Seasonal illness - **West Nile Symptoms:** Mild disease in humans (fever, headache, nausea) - complications: encephalitis or meningitis in an aged population - **West Nile Test:** ELISA for antibody production - **West Nile Treatments:** No treatment, only prevention - no vaccine for humans, yes for horses - **Yellow Fever Virus:** Positive sense ssRNA virus - **Yellow Fever Vector:** Mosquitos - **Yellow Fever Reservoir:** Monkeys - **Yellow Fever Symptoms:** Fever, nausea, vomiting (black vomit), jaundice, hemorrhagic - **Yellow Fever Treatment:** Self-limiting - vaccine available (either survive or not) - **US Biological Weapon Research:** Yellow fever virus - **Viral Encephalitis:** Inflammation of the brain - **Viral Encephalitis Vector:** Mosquito - **Types of Viral Encephalitis:** All caused by different viruses - **Most Deadly Viral Encephalitis:** EEE: Eastern equine encephalitis - **Viral Encephalitis Host:** Horses - **Viral Encephalitis Carriers:** Horses to birds as intermediate carriers, and then to humans - **Dengue Fever Symptoms:** Severe bone and joint pain, high fever, headache, malaise - **Dengue Fever Virus:** Flavivirus with 4 subtypes - since more than 1 subtype you can be infected more than once - **Dengue Fever Resolution:** No treatment, no vaccine - self-limiting - **Dengue Fever, Multiple Infections:** Second infection from different immunological types causes hemorrhagic disease and extreme immune response - **Dengue Fever Vector:** Mosquito (_Aedes aegypti_) - **Viral Diseases Caused by _A. aegypti_:** - 1. Chikungunya - 2. Zika - **Chikungunya Virus Carrier:** _A. aegypti_ mosquitos - **Chikungunya Virus Symptoms:** Fever, joint pain in hands/feet, rash, muscle pain, swelling - **Chikungunya Treatment:** Self-limiting, feel better in a week - **Zika Virus Symptoms:** Similar to other viral diseases, most people won't have any symptoms or they are very mild - **Zika Virus Spread:** Mosquitos - from pregnant woman to fetus - sex with infected person - **Zika Carrier:** _A. aegypti_ mosquitos - **Arthropod-Transmitted Diseases: Protozoa:** - 1. Malaria - 2. Leishmaniasis - 3. Sleeping sickness - 4. Chagas disease - **Malaria:** "Bad air" - "Head for the hills" - **Malaria Etiology:** Spread through _Plasmodium_ species (single-cell protist, eukaryote) - **_Plasmodium_ Types:** - 1. _P. vivax_ (most common) - 2. _P. falciparum_ (most deadly) - 3. _P. ovale_ - 4. _P. malariae_ - **_Plasmodium_ Life Cycle:** Very complex - **Malaria Vector:** Mosquito - _Anopheles_ (females only) - biological vector - **Malaria Hosts:** Humans and mosquitos - **_Plasmodium_ Life Cycle:** - 1. Human infected by sporozoite form in mosquito salivary gland during bite. - 2. Cells travel to the liver and replicate, develop, and emerge from liver and infect RBCs. - 3. Development in RBCs results in death of RBCs and infection of new cells. - 4. Gametocytes released by RBCs are taken up by mosquitos during blood meal. - 5. Gametocytes develop into gamete, fuses and forms zygote. - 6. Migrate to the salivary gland for a new cycle. - **Malaria Diagnosis:** Presence of _Plasmodium_ in the blood smear. - **Malaria Treatment:** - 1. Quinine (chloroquine): first effective drug, kills merozoites. - 2. Primaquine: kills sporozoites, merozoites, and gametes. - 3. Artemisinin. - Drug resistance evolving. - **Ancient Malaria Treatment:** Previously used gin and tonics, cinchona tree - **Malaria and Sickle Cell:** Parasite cannot develop in individuals with abnormal hemoglobin or sickle cell anemia - only in heterozygous indivduals with sickle cell - **Malaria and G6PD:** G6PD deficient patients (deficient in a type of RBC) are resistant to malaria - in West Africa, some individuals have an MHC combination that _plasmodium_ cannot invade. - **Malaria Prevention:** Prophylactic drugs taken before trip (chloroquine, doxycycline, atovaquone, proguanil) - reduction of mosquito habitat - insecticides - bed nets - **Malaria Vaccine:** Approved by the WHO in 2021 - **Leishmaniasis:** Kala azar - cause: _Leishmania_ protozoa - **_Leishmania_ Life Cycle:** - 1. Sandfly (biological vector) - 2. Human - 3. _Leishmania_ promastigotes (amastigotes in human) - **Leishmaniasis Symptoms:** Skin lesions, or can invade whole body (fatal) - **_Leishmania_ Vector:** Sand flies - biological vector - **Leishmaniasis Treatment:** Drugs available, but with strong side effects - **_Leishmania_ Common:** Common to soldiers in Iraq - Baghdad boil - **African Sleeping Sickness Cause:** _Trypanosoma brucei_ - **African Sleeping Sickness Vector:** Tsetse fly - **African Sleeping Sickness Treatment:** Drugs are toxic, resistance develops - **_Trypanosoma_ Life Cycle:** - 1. Fly injects metacyclic trypomastigotes when it feeds on blood - 2. Metacyclic trypomastigotes transform into trypomastigotes and reproduce asexually in bloodstream - 3. Fly ingests trypomastigotes when it feeds on blood - 4. Parasite reproduces asexually in fly gut and migrates to salivary glands - 5. Fly injects metacyclic trypomastigotes when it feeds on blood - **African Sleeping Sickness Symptoms:** Coma, swelling of lymph nodes - **Chagas Disease Cause:** _Trypanosoma cruzi_ - **Chagas Vector:** Reduviid bug vector (kissing bug) - **Chagas Symptoms:** Initial disease often mild, but chronic disease later is fatal - causes heart problems. - **Chagas Disease Treatment:** Drugs most effective during initial infection - **_Trypanosoma cruzi_ Life Cycle:** - 1. Vector bites human and defecates on skin. - 2. Metacyclic trypomastigotes are rubbed into eye or bite. - 3. Enter cells and reproduce. - **Chagas Disease and Autoimmunity:** In chronic stage, little or no detection of parasite - lesions on the heart, and heart transplant is the only cure - protozoa is similar to the heart muscle antigenically - autoimmune response - **Lymphatic Filariasis:** Elephantiasis - helminths carried by arthropods - legs extremely swollen - Fr. Tom from ND had a grant to assist in Haiti - **Lymphatic Filariasis Development:** Parasitic worms (threadlike nematodes) have larvae (microfilariae) that enter host by bite of mosquito (blood meal) - mature and mate in bloodstream - migrate to lymph nodes - make nests in lymph nodes that block drainage - **Lymphatic Filariasis Treatment:** Once it occurs, it cannot be reversed - male hydrocoel can be surgically repaired - anti-worm drugs (mectizan) are given in yearly large doses and can help kill adult female worms - prevention of secondary infections - yearly mectizan - drugs in salt - bed nets - **Loaisis:** Worms transmitted by arthropods - _Loa loa_ worm transmitted by deer flies - adult worms live in the eyes - microfilaria in blood during the day - **River Blindness:** Roundworm-microfilaria transmitted by blackflies - worms invade eye and blood vessels become fibrous - almost all over 40 blind - children help the elderly - **Soil Borne Diseases - Fungi: Types:** - 1. Yeast (single cell) - 2. Molds (mycelia - important pathogens of plants) - **Types of Fungal Diseases:** - 1. Hypersensitivity (allergy) - 2. Mycotoxins (some release dangerous toxins) - 3. Mycoses (fungal infection on or in the body, problem for the immunocompromised) - **2 Types of Fungal Skin Diseases:** - 1. Candidiasis (_Candida albicans_) - thrush, vaginitis, nails - 2. Madura foot (soil organisms, including fungi) - **Other Fungal Infections:** - 1. Athlete's foot - 2. Fungal eye infection - 3. Ringworm - **Fungal Disease Treatment:** Topical to limit toxicity (target fungal cell wall and chitin) - **Cells in Fungi:** Eukaryotes - **Fungi Targets:** Unique sterol-ergosterol-azoles - **Tetanus Bacteria:** _Clostridium tetani_ - **_Clostridium tetani_:** Obligate anaerobic, endospore forming, gram-positive rods found in soil - **Tetanus Mechanism:** Potent toxin - soil contaminated wound (deep puncture) - **Tetanus Treatment:** Anti-toxin and antibiotics - **Tetanus Prevention:** Vaccine - **Common Source of Tetanus Infection:** Water - **Potable Water:** Fit for human consumption - drinking water - **Water Contamination:** Feces - *E. coli* is the indicator organism - **Coliform Bacteria:** Facultative aerobic gram-negative and non-spore forming rods - ferment lactose with gas - most are enteric bacteria - **Types of Coliform Bacteria:** - 1. *E. coli* - 2. _Klebsiella pneumoniae_ - 3. _Enterobacter_ - **Coliform Test:** Water through a filter of known pore size - filter on EMP plate (selective and differential for coliform bacteria) - if bacteria ferment lactose, it will turn shiny green - **Water in Developed Countries:** Very little waterborne disease - **Water in Developing Countries:** Waterborne diseases are a major problem - **Primary Sewage Treatment:** Physical removal: screens, skimmers, sedimentation - **Secondary Sewage Treatment:** Biological removal: uses bacteria to decompose organic waste - **Tertiary Sewage Treatment:** Chemical and physical: sand/charcoal filters then chlorine or UV light - **Activated Sludge Floc:** Bacteria in sludge from sewage (zooglea ramigera) - forms polysaccharide slime layer - **Septic Tanks:** Microbes decompose sludge that accumulates - still must be pumped - gravel and soil do final filtration - precipitation of insoluble particles by addition of alum - **Water Purification Through Flocculation:** Precipitation of insoluble particles by addition of alum - **Water Purification Through Filtration:** Through sand or charcoal: removes most microorganisms - **Water Purity Check:** Coliform test - **Bacterial Traveler's Diarrhea:** Waterborne disease - caused by