Viruses and Their Disease – Flashcards

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Smallpox Virus
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Type: Enveloped DS DNA Virus cause by the Variola virus

Disease: Contracted through Respiratory route. Primary viremia leads to infection of macrophages. Replication occurs and secondary viremia occurs.
Symptoms: Skin rash after 9-12 days of infection. Contagious at onset of rash. progresses to papules which break in 4-6 days. 2-4 weeks for healing. Rash predominant in extremities.

Europeans have premunition

Diagnosis: Symptoms, serology

Treatment: None

Prevention: Vaccine from cow pox.
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Chicken Pox
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DS DNA virus (Herpes)
Caused by Varicella-Zoster virus
connection to shingles
Disease: Respiratory Route, infections lymphs nodes and causes viremia. Virus is shed from 1-3 days before rash appears until rash subsides (1 wk) Lodges in neural ganglia and is latent. Reactivation results in shingles.
Diagnosis: Symptoms, Serology
Treatment: Chicken pox= none Shingles= antivirals
Prevention: Vaccines available
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Herpes simplex Type 1 and Type 2
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Both are enveloped DS DNA viruses

Type 1 is transmitted via respiratory route

Type 2 is sexually transmitted

Both are latent.

Disease: Type 1 causes cold cores, keratoconjuctivitis (leading cause of acquired blindness) and encephalitis
Type 2 causes genital lesions.

Diagnosis: Symptoms, serology

Treatment: Acyclovir

Prevention: No vaccine. Watch who you kiss and have sex with
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Viral Latency
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the ability of a pathogenic virus to lie dormant within a cell. Latent viral infections are persistent but differ from chronic infection
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Clinical latency
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The incubation period where the virus is not dormant
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Episomal Latency
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exists in the cytoplasm or in the nucleus as a separate extrachormosomal structure
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Proviral Latency
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Integrates in the host genome and is considered "self"
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Epstein-Barr Virus
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Enveloped, DS DNA virus
Responsible for infections mononucleosis, transmitted by direct contact and the respiratory route.

Disease: oropharynx where it multiplies and then infects the B-calls. Incubation from 30-50 days. First symptoms are fever, headache, fatigue, malaise and sore throat. 2-4 weeks for symptoms. Can be latent and cause chronic fatigue syndrome.
College students are predisposed
EBV can cause Burkitts lymphoma in blacks and nasopharyngeal cancer in Chinese.
Diagnosis: Symptoms, Serology

Treatment: Bed rest, symptomatic relief

Prevention: good health, avoid infected peeps
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HPV
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SS DNA virus associated with plantar warts, genital lesions, oral lesions and cervical cancer.

look like cauliflower florets

Prevention: Abstinence, vaccine called Gardasil
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Rubeola virus
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Causes measles (hard measles)
Enveloped SS RNA virus
Contracted through the respiratory route
Extremely contagious
Disease: 0-11 day incubation leading to fever, malaise, coughing, sneezing, conjuctivitis, photophobia and Koplik's spots in mouth.
2-3 days after infection, skin rash occurs on head and moves toward body
Diagnosis: Symptoms, Serology
Treatment: None
Prevention: MMR vacine
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Mumps
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Enveloped SS RNA virus
Respiratory Route
Disease: 7-25 day incubation, swelling of the parotid glands is the tell tale sign lasting about a week
May have testicular damage in 20% of males. Can kill fetus.
Diagnosis: Symptoms, serology
Treatment: None
Prevention, MMR vaccine
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Rubella
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German, or soft measels
enveloped, SS RNA virus
Respiratory Route
Disease: 2 week incubation period, 5-7 viremia, skin rash and fever occur for 2-3 days.
Diagnosis: Symptoms, Serology
Treatment: None
Prevention: MMR vaccine
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Influenza Virus
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Enveloped ss RNA virus. Specific receptors called nauraminidase and hemagglutinin.
Very rapid antigenic variation
Three types, A, B, C.
Disease: 1-2 incubation, fever malaise myalgia, sore throat, coughing, sneezing and prostration, nausea and vomiting may occur. No aspiring for kiddies, Reye's syndrome.
Diagnosis: Symptoms, Serology
Treatment: ANti-flu
Prevention: Hand washing
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Polio Virus
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non-enveloped ss RNA virus
Fecal-oral route
3 types, 1,2,3
Disease: 1-2 week incubation. May have mild fever or diarrhea. In 1%, viremia occurs leading to motor neuron infection and neck pain, fever and paralysis occur due to demyelination
Contagious: about 1 week before onset to 3-6 weeks in stool
Diagnosis: Symptoms, serology
Treatment: none
Prevention: Hygiene, Salk and Sabin.
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Rabies
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hydrophobia is the biggest indicator
SS RNA virus that is bullet shaped
transmitted by animal bites and bat poop inhalation
Disease: 1-3 month incubation, closer bite to head, shorter incubation. nearly 100% fatal in humans. Fever, malaise, and headache followed by neurological changes (mood swings, depression, mania, forgetfulness, etc)
Terminal symptoms include delirium and coma.
Diagnosis: Test offending animal for rabies.
Treatment: vaccine given after bite.
Prevention: Don't get bit
Contagious:no human to human unless you eat or bite them
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Coxsackie Virus
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non-enveloped SS RNA virus that causes hand-foot-and-mouth disease
Two serogroups of the enteric virus, A and B.
Type A causes hand-foot-and-mouth.
Symptoms include fever, sore throat and herpangina (painful blisters in mouth) and blisters on the hands or feet.
Transmitted by direct contact, fecal/oral route and respiratorally. Most are contagious within first week of infection.
Diagnosis: Symptoms, serology
Treatment: None
Prevention: none, wash hands.
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Hepatitis
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The major hepatitis infections are caused by non-enveloped SS RNA picorna virus (Hep A) or by an enveloped DS DNA hepadnavirus (Hep B)
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Hep A
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SS RNA picrona Virus
Disease:short incubation transmitted by fecal/oral route. nausea, vomitting, anorexia, prostration and fatigue. Viremia probably occurs. Symptoms gone in 1-2 weeks.
Diagnosis: Symptoms, serology
Contagious: 15-45 days before onset, 1 week during
Treatment: none
Prevention: hygiene and gamma globin prophylactic therapy. There is a vaccine.
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Hep B
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fecal/oral, respiratory, parental and sexual transmission.
long incubation period, jaundice, fever, elevated transaminases, prostration and fatigue occur. Associated with liver cancer.
Diagnosis: Symptoms, serology
Treatment: None
Contagious: whole life is they have chronic version
Prevention: Vaccines available
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Hep C
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positive stranded RNA virus spread paternally, sexually and vertically.
Diagnosis: Symptoms, Serology
Contagious: whole life
Treatment: None
Prevention: Avoid high risk behavors
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Lentiviruses
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enveloped ss RNA viruses that employ reverse transcriptase, retroviruses.
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HIV
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Human Immunodeficiency virus causing AIDS. Two subgroups, HIV 1 and HIV 2.
Disease: sexually, paternally and horizontally transmitted from mother to fetus. Poorly transmitted by saliva and casual contact. 100X more likely to transmit if other STD present
Ten year incubation. Viremia for about a month. Mimic mono. Monocytes which express CD4+ are infected. Attacks neural cells leading to AIDS dementia.
Immune system shuts down and victim is succeptiable to cancers (Kaposi's Sarcoma, Burkitt's Lymphoma.)
Diagnosis: Symptoms, serology
Treatment: nucleic acid analogs or protease inhibitors.
No vaccine
Prevention: Education, no high risk behaviors.
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Viral Oncogenesis
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all tumor-associated viruses have a DNA genome or DNA provirus.
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Proto-oncogenes
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naturally occurring genes, found in our genome or in retroviral genomes, which when activated, result in cancer
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Tumor-suppressor genes
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genes which encode proteins that inhibit expression of oncogenes.
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Promotor
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regulatory site on DNA upstream of a gene where the polymerase binds to initiate transcription.
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Gram positive
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single membrane, thichk cell wall and teichoic acids.
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Gram negative
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Inner and outer membrane, thin cell wall and lipopolysaccharide.
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Diagnosis of bacterial disease
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-Patient History
-Symptoms (pathognomonic is one specific to the infectious agent)
-Direct Examination of infected sites
-changes in normal tissues
-samples taken and placed in enriched medium
-Cultivation to check for hemolysis (beta is complete, alpha is partial, gamma is none)
-Biochemistry for metabolic functions using Bergey's Manual
-Serology
-Animal Testing (rare)
-Antibiotic sensitivity testing
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Staphylococcus aureaus
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Gram + and found everywhere, Has coagulase, is aerobic to microaerophilic. resistant to drying. Drug resistant because of beta-lactamase production.
Virulence Factors: Toxins/enzymes (catalase, coagulase, hyaluronidase, staphylokinase, etc)
Disease:food poisoning to bateremia to disseminated abscesses. Dermonecrosis and inflammation lead to pus and often carbuncles. Can onset toxic shock syndrome.
Diagnosis: Symptoms, smears, cultivation, catalase test, coagulase test, serology
Treatment: Antibiotics
Prevention: no vaccine. Transmitted by direct contact, nasal droplets, fomites, etc, so proper hygiene.
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Streptococcus pyogenes
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Gram +. Small spheres, grow poorly on solid media, considered fastidious.
Virulence Factors:
Streptokinase- dissolves blood clots
Stretodornase- Dnase
Hyaluronidase- degrades hyaluronic acid
Pyrogenic toxins A-C- cause fever and rash in scarlet fever
Hemolysins-
Streptolysin O- inactivated by O2
Streptolysin S- O2 stable
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Common tests for strep
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Bacitracin Test/Hemolysis Test
Catalse Test
Oxidase Test
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Diseases caused by group A S Pyogenes
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Erysipelas, Puerperal Fever, Sepsis, Sore Throat, Scarlet Fever, Impetigo, Acute endocarditis, Streptococcal Toxic shock syndrome, Necrotizing fasciiitis, Rheumatoid arthritis
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Diseases caused by group A S Pyogenes
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Erysipelas, Puerperal Fever, Sepsis, Sore Throat, Scarlet Fever, Impetigo, Acute endocarditis, Streptococcal Toxic shock syndrome, Necrotizing fasciiitis, Rheumatoid arthritis
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Rheumatic Fever
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1-4 weeks following respiratory infections like strep
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Glomular Nephritis
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1-4 weeks following skin infection especially M 12, 4 2, 49
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Diagnosis, treatment and prevention of Streptococcus pyogenes
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D: Symptomology, smears, culture, serology
Treat: antibiotics, penicillin G and erythromycin (inhibits protein synthase)
Prevention: No vaccines, hygiene, isolation, antisepsis, early diagnosis/treatment.
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Other Streptococci
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S. Mutans- cause of dental caries
S. pneumonia- bacterial pneumonia in children.
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Gram - diplococci
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Description: diplococci that appear kidney shaped, sharing a cytoplasm, they are small, fastidious, and possess cytochrome oxidase.
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N. meningitidis
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Causes inflammation of the meninges
Transmission: respiratory droplets, tranformation. 13 unique polysaccharide capsules.
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N meningitidis- Disease
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Disease: causes nasopharyngitis (sore throat), can cause meningococcemia (miningitidis in blood), petechial lesions, shock occu. If adreanal glands are infect, can lead to waterhouse-frederichsen syndrome (death in 2 hours)
Spinal meningitis follows meningococcemia, 85% chance of death.
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N. Meningitidis Diag, treat and prev
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Diagnosis: Symptoms, presence of gram - diplococci in smears, cultivation of oxidase and catalase positive bacteria.
Treatment: Antibiotics
Prevention: Vaccination with capsular polysaccharide

also look for brudzinski's sign for severe case.
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N gonorrhoeae
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only in humans
veneral or sexually transmitted disease, can infect any mucosal surface. First known example of HGT of human to a bacterial pathogen. No capsule, but has a polyphosphate coat
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Virulence factors of N. Gonorrhoeae
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Pilli for attachment
IgA protease- destroys IgA
Sialyltranferase- adds sialic acid to host
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Why is N. gonorrhoeae hard to control?
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Remarkable Antigenic variation
No diagnostic screening test
No effective vaccine
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N gonorrhoeae
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only in humans
veneral or sexually transmitted disease, can infect any mucosal surface. First known example of HGT of human to a bacterial pathogen. No capsule, but has a polyphosphate coat
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Diseases associated with N. Gonorrhoeae
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Gonorrhea- std in genitals or throat
Pelvic Inflammatory Disease-Infection in lover female reproductive tract spreading to upper female reproductive tract.
Disseminated gonoccal infection- bateremic spread of STD leading to inflammation of tendons and skin, skin rash, 4x more likely in women
Opthalmia neonatorum-Blindness in infants
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Disease in Males from N. Gonorrhoeae
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uncomplicated male urethritis- pus and pain on urination, overactive PMNS, resolve in several months untreated.
Can lead to sterility by moving up the urethra into the vas deferens where epididymtis leads to blockage of sperm ducts.
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Disease in Females from N. gonorrhoeae
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Urethritis can occur but more commonly its cervicitis.
Can infect the salpinges leading to salpingitis, called Pelvic Inflammatory Disease. Chronically it can lead to sterility. 1 in 100 lead to disseminated gonococcal infection by bacteremia, leading to rare encephalitis and death.
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N. Gonorrhoeae Diag, treat, prev.
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Diagnosis: Symptoms, the presence of gram neg diplococci and colutivation of oxidase positive bacteria.
Treatment: Antibiotics
Prevention: abstinence, barrier contraceptives, no vaccine
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