Microbiology: Unit 4 review
Define prion and identify a human disease associated with a prion.
Prion are proteinaceous infectious particles that appear to lack nucleic acid (genetic material) Creutzfeldt-Jacob Disease (CJD)
Identify the four clinical phases of rabies.
Prodromal phase fever, nausea, vomiting, headache and other non specific symptoms. Furious phase first acute sign of neurological involvement including agitation, seizures, and disorientation. Spasms in the neck and pharyngeal muscle lead to severe pain upon swelling. Attempt to swallow or sight of liquid brings on hydrophobia. Dumb phase patient is not hyperactive but paralyzed, disoriented and stuporous. coma phase if left untreated will progressed to this phase. Death results from cardiac or respiratory failure.
Define lysogeny conversion and identifying several bacterial toxins produced by this process
A bacterium acquires genes from its temperate phage that code for toxins or enzymes that can cause pathology in humans. Diphtheria toxin, cholera toxin and botulism toxin are examples of lysogenic conversion.
Identified several differences in the multiplication cycle of a bacteriophage as compared to an animal virus.
Absorption Bacteriophage precise attachment of special tail fibers to cell wall. Animal virus attachment of capsid or envelope to cell surface receptors. Penetration Bacteriophage Injection of nucleic acid through cell wall, no uncoating of nucleic acid. Animal virus whole virus is engulfed and uncoated or virus surface fuses with the cell membrane, nucleic acid is released. Synthesis and assembly Bacteriophage occurs in cytoplasm. Animal virus occurs in cytoplasm and nucleus. Viral persistence Bacteriophage lysogeny Animal virus latency, chronic infection, cancer Release from host cell Bacteriophage cell lyses Animal virus lyses or budding. Cell destruction Bacteriophage immediate Animal virus immediate or delayed
Identify treatment options for herpes simplex and HPV.
Acyclovir is the most effective treatmen for Herpes simplex. HPV treatments include physical removal by freezing, cauterization, laser surgery, chemical applications of salicylic acid & podophyllin for genital warts.
Discuss the naming of the following DNA viruses: adenovirus and cytomegalovirus.
Adenoviruses named from virus originally isolated from the adenoids of young children. Cytomegaloviruses are named for their tendency to produce giant cells with nuclear and cytoplasmic inclusions
Compare antigenic shift and antigenic drift.
Antigenic shift - constant genetic change of the glycoprotein through mutation. Antigens gradually change their amino acid composition. Results in decreased ability of host memory cells to recognize them. Antigenic drift - more drastic changes. Viral genome consists of just 10 genes encoded on 8 separate RNA strands. Antigenic shift is the substration of one of these genes or strands with a gene or strand from an influenza virus originating from a different animal hosts.
Compare chronic and latent viral infection
Chronic viral infections in a chronic infection the virus is detectable in tissue samples and is multiplying at a slow rate. Symptoms usually are mild or absent. HIV and hepatitis B virus are examples. Latent viral infections virus enters a dormant stayed inside host cells and becomes inactive. Not multiplying, generally not detectable and does not cause symptoms. Virus can be reactivated and give rise to recurrent infections. Herpesviruses are examples.
Define cytopathic effects and provide several example
Cytopathic effects are virus induced damage to the cell that alters its microscope appearance. Gross changes in size or shape. Intracellular changes. Inclusion bodies are compacted masses of viruses or damaged cell organelles. Formation of syncytia fusion of multiple host cells into large cells with multiple nuclei. Cell membranes fuse together.
Identify the difference between a temperate phage and a prophage.
DNA phages called temperate phage undergo absorption and penetration into the bacterial host but are not replicated or immediately released. Viral DNA enters an inactive prophage state (latent) and is inserted into the bacterial chromosome.
Identify three initial screening tests associated with HIV and identify the test that would be used to rule out false positives.
ELISA, Latex agglutination and Rapid antibody tests. Western blot test used to rule out false positive results from previously mentioned approved test.
Identify five general phases of the multiplication cycle in animal viruses and identify major events occurring in each phase.
General phases absorption, penetration, synthesis, assembly and release. Absorbtion attachment specifically to receptor sites on the cell membrane Pentration viral envelope fuses directly with the host cell membrane the nucleocapsid will be translocated into the cytoplasm the nucleocapsid will be uncoated releasing the nucleic acid. Synthesis involves nucleic acid replication and protein production . DNA viruses are replicated and assembled in the nucleus. RNA viruses are replicated and assembled in the cytoplasm. Assembly an envelope viruses, spikes are inserted into the host cell membrane, so that they can pick up during budding (exocytosis) Released through cell lysis (non-enveloped). Released through budding (exocytosis) for envelope viruses.
Identify the DNA virus associated with the Dane particle
HBV
Discuss the latency associated with HSV-1 and HSV-2
HSV-1 enter the trigeminal nerve which inner vats the oral region. The trigeminal nerve has three branches. Ophthalmic branch (eye), maxillary branch (upper lip) and mandibular branch (lower lip) HSV-2 because latent in the lumbosacral ganglia. Recurrent infection is triggered by various stimuli. Fever, UV radiation, stress or mechanical injury will reactivate viral genes.
Identify the functions of hemaglutinin and neuramidase in the Influenza virus
Hemaglutinin binds to respiratory mucosal receptors (induce viral entry) and triggers endocytosis. Neuramidase breaks down the respiratory mucus. Keeps viruses from sticking together. Assist in fusion to and budding from the host cell.
Identify the virus that is ssDNA virus
Parvoviruses
Identify and define the progression of lesions in the smallpox virus.
Progression of the disease Macule is a flat, lesion. Papule is a elevated lesion. Vesicle is a fluid-filled lesion. Pustule is a pus filled lesion. The pustule will eventually crust over leaving nonpigmented sites with scar tissue.
Identify the RNA virus associated with Negri bodies.
Rabies
Identify the virus that is a dsRNA virus
Reovirus
Identify the route of transmission and prevention of the following DNA viruses: smallpox, HSV, chicken pox, shingles, Epstein-Barr, HBV and HPV.
Smallpox route of transmission exposure through inhalation of droplets or skin crust. Prevention focused on isolation and smallpox immunization. HSV- direct exposure to secretions containing virus. Prevention includes avoid sexual contact. Medical personnel to wear gloves. chicken pox- route of transmission respiratory droplet and contact with infectious wounds. Prevention includes varivax vaccine avoid direct contact with infectious wounds. shingles- route of transmission respiratory droplets and contact with infectious wounds. Zostavax vaccine. avoid direct contact with infectious wounds. Epstein-Barr- route of transmission is direct oral contact and contamination with saliva. Prevention avoid contact. HBV- route of transmission blood semen vaginal secretions. Prevention vaccine recombivax, energix and heptavax. HPV- route of transmission contact with wart or contaminated formite. Prevention vaccine Gardasil and cervarix.
Identify functions of the viral capsid and envelope
The outermost covering protects the nucleic acid from various enzymes and chemicals when the virus is outside of the host cell. Capsids and envelopes assist in attachment to the host cell and penetration of the nucleic acid into the host cell. Components of capsids and envelopes stimulate the production of antibodies by the immune system. Antibodies neutralize viruses and protect host cells from future infections.
Identify treatment options for influenza and HIV.
Treatment options for influenza includes zanamivir (Relenza) and Tamiflu. Treatment options for HIV is AZT (azidothymidine)
Compare viroids and prions and Identify a disease linked to each of these infectious agents.
Viriods composed of naked strand of RNA. They target plants. Examples include potato spindle tubal disease and chrysanthemum stunting. Prions derived from proteinaceous infectious particle. Primary structure is a protein; lacks DNA or RNA. Diseases are transmissible spongiform encephalopathies spread host to host by direct contact with contaminated food. Example Creutzfeldt-Jacob disease and kuru.
Discuss the naming of the following RNA viruses: coronvirus, arbovirus, picornavirus, coxsackievirus, echovirus, reovirus and rotavirus.
coronvirus- named for the resemblance of the viral spikes to a crown. arbovirus - are ARthropod-BOrne. (Transmitted by arthropods) picornavirus- named for their small size and RNA core. coxsackievirus- named after being first isolated in Coxsackie, NY. echovirus- (Enteric cytopathic human orphan virus) reovirus - respiratory enteric orphan virus rotavirus- have a wheel shaped capsid.
Identify human diseases associated with herpes simplex 1 and 2, varicella-zoster, Epstein-Barr, HHV-6, HHV-8, HBV, adenoviruses, HPV and parvoviruses (B-19).
herpes simplex 1 - fever blisters herpes simplex 2 - genital infections varicella-zoster - chickenpox and shingles Epstein-Barr - Burkitt lymphoma & Mononucleosis HHV-6- Roseola HHV-8- Kaposi sarcoma HBV- Hepatocellular carcinoma adenoviruses- ketatoconjuctivitis & infantile gastroenteritis HPV - seed wart, planter wart, flat wart, genital warts & cervical cancer parvoviruses (B-19)- Fifth disease
Identify the route of transmission and prevention of the following RNA viruses: influenza, hantavirus, measles, mumps, rabies, rubella, West Nile, yellow fever, Dengue fever, HIV, polio, hepatitis A, rhinovirus, norovirus.
influenza route of transmission inhalation of aerosol and droplets prevention flu vaccine hantavirus route of transmission spread by dried animal waste that have become airborne when rodent nest are disturbed. prevention measles route of transmission by respiratory aerosols prevention MMR vaccine. mumps route of transmission transmitted primarily through salivary and respiratory secretions prevention MMR vaccine. rabies route of transmission spread to humans by bite, scratches and droplet inhalation. Prevention vaccine human diploma cell vaccine rubella route of transmission infection through contact with respiratory secretions prevention MMR vaccine West Nile route of transmission mosquito bites prevention vector control in animal surveillance has reduced the incident yellow fever route of transmission to patterns of transmission urban cycle between humans & mosquito. Sylvan cycle between forest monkeys and mosquitoes prevention vector control in animal surveillance Dengue fever route of transmission by Aedes mosquito Prevention vector control in animal surveillance HIV route of transmission occurs mainly through sex and blood transfer Prevention abstaining from sex, monogamous relationship, education, barrier protection, avoiding IV drugs. polio route of transmission virus is transmitted on food, water, objects contaminated with feces and mechanical vector. prevention polio vaccine. hepatitis A route of transmission spread fecal-oral occasionally spread by blood or blood products Prevention immunization (Havrax or Vaqta) rhinovirus route of transmission people acquire infection from contaminated hands and formite. Lesser extent from Droplet nuclei. Prevention wash your hands. norovirus route of transmission fecal-oral route Prevention wash your hands
Identify human diseases associated with measles, coronaviruses and polio.
measles Koplik's spot, subacute sclerosing panencephalitis (SSPE) coronaviruses- SARS (Severe acute respiratory syndrome) polio- post-polio syndrome (PPS) Bulbar poliomyelitis
Identify the function of the following enzymes associated with HIV: reverse transcriptase, integrase and protease.
reverse transcriptase- converts single-stranded RNA into double-stranded DNA integrase- DNA can become inactive in the nucleus of the host cell and become integrated into host DNA. protease- block final assembly and maturation of the virus.
