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Bacteriophage life cycle of the Lytic
1: Attachment occurs when a phage's tail fiber match with a receptor site on the bacterium's cell wall.2. Penetration occurs when the phage tail releases lysozyme to dissolve a portion of the cell wall. (Phage DNA is injected into the bacterial cytoplasm). DNA is transcribed & translated3:Biosynthesis is the production of new phage genomes and capsid parts.4:Maturation is the assembly of viral parts into complete virus particles.5:Release is the exit of virions from the baterium. (lysis-cell ruptures) TERM 2
Lytic vs Lysogenic
DEFINITION 2 Lytic: Active infection (5 step process)Lysogenic: Viral genome inserts into bacteria genome, known as prophage (bacteriophages participating in this cycle are known as temperate phages). It continues to replicate normally (binary fissions) each time daughter cells containing the viral genome. At sometime the bacterial cells become stressed (lack of nutrients, etc) and triggers prophage to excite itself from bacterial X and switch to lytic cycle, lysing the cells as new lambda phage are released. TERM 3
Viruses
DEFINITION 3 -Sumicroscopic and have either DNA or RNA genome. Obligate intracellular particles (cannot replicate on its own)-A small infectious agent that replicates only inside the living cells of other organisms. Viruses can infect all types of life forms, from animals and plants to bacteria and archaea.-No organelles, no cytoplasm, no cell nucIeus or nucleoid.-Contain 2: Nucleic acid core & a surrounding coat of protein TERM 4
Nucleic Acid Core
DEFINITION 4
1:Either double or single stranded, linear or cicular molecule
but may exist as segments (influenza virus). The viral
genome is folded or coiled inside.
TERM 5
Protein Coat
DEFINITION 5 2: AKA capsid, gives it shape. It is dubdivided/made of single protein units calledcapsomeres, and thecapsidwith its enclosedgenomeis referred to as a nucleocapsid-Helps is resist temp., pH and enviormental fluctuaions.-Spikes: capsid proteins help attach the virus to the host cell and facilitates in penetration of the cell.Those with only a nucleocacpsid are called "naked"- Envelope: flexible membrane surrounding nucleocapsids, it is acquired from the host cell during replication and is unique to each. -They may lose infectivity if envelope is destroyed
Virion
A completely assembles and infectious virus outside its host
cell.
TERM 7
Shape of Viruses: Helical, Isocahedral,
Both
DEFINITION 7
Helical: Have helical symmetry (Think of screw rod or
spring)Iso: Isocahedral symmetry (20 triangular faces, 12
corners)Both: helical and isocahedral have complex
symmettry. (little animal)Poxvirus: brick shape w/ filaments
also a complex virus
TERM 8
Host Range of
Virus
DEFINITION 8 Refers to what organisms (host) the virus can infect and it is based on a virus' capsid structure.-Within its host range, viruses only infect certain cell types or tissues.This limitation is tissue tropism/attraction. The virus needs specific receptor in order to invade host cell.-If a potentional host cell lacks the appropriate receptor or the virus lacks the complementary protein, the virus usually cannot bind to or infect the cell. TERM 9
Classification of
Virus
DEFINITION 9
Do not use conventional taxonomic groups.-DNA Viruses:
contain single or double stranded DNA genomes-RNA
Viruses: contain single or double stranded RNA genomes.
(+)strand RNA viruses have mRNA genomes.(-)strand RNA
viruses have RNA strands that are complementary to mRNA
TERM 10
Retroviruses
DEFINITION 10
Replicated individually through a DNA intermediate (RNA-
>DNA -> RNA) Instead of DNA->RNA->Protein. This
intermediate is formed using reverse transcriptase enzyme
that is carried within the virion.
Difference b.t. plaque and colony
Colony refers to a cluster of particular bacteria developed in
a medium.Plaque refers to a clear zone, produced by a Phage
which is formed by lysis of the bacterial cells in the medium.
TERM 17
Cancer
DEFINITION 17 Uncontrolled growth (mitosis) and spreading of cells.-Tumor:Clone of abnormal cells-Normally the body responds to a tumor by surrounding it with a capsule of connective tissue, and is noted benign.-Tumor of cells can break free from the capsule and spread into other tissues of the body (metastasis) and the tumor is noted malignant, individual now has cancer. TERM 18
Carcinogens
DEFINITION 18 Cancer causing chemicals and agents that produce cellular changes leading 60%-90% to of cancer. Ex: hydrocarbons on cigarettes, pesticydes, dyes, It's a multi-hit theory-A mix of 2-4 will cause cancer.-Oncogene: Viruses transform from normal cell to abnormal cell aka cancer. EX: Epstein-Barr Virus (cancer of the jaw), HPV (cervical cancer-we have a vaccine) TERM 19
Proto-oncogenes
DEFINITION 19
Normal genes that are theorized to reside in the DNA of a
cell. They can be transformed into oncogenes by:
radiation
chemical
carcinogens
DNA damage
viruses
TERM 20
Emerging Infectious Deseases
DEFINITION 20 The result of viruses appearing for the first time in a population or rapidly expanding their host range. Most of these viruses are not new.-Genetic recombination: can lead to "new" viruses. The virus has multiple combinations of genome segments that cause different infections.-Mutation:a change of the nucleotide sequence of the genome of the virus. They can occasionally be advantageous and create a new virus or strain of virus.
3 hypotheses for the origin of viruses
- Regressive Evolution Hypothesis:Degenerate life forms. They're derived from intracellular parasites that have lost functions and retained only the genes necessary for their parasitic way of life.2. Cellular Origins Hypothesis:Derived from fragments of cellular components and macromules that escaped from cell walls and replicated inside hosts.3. Independent Entities Hypothesis:They co- evolved with cellular organisms from self-replicating molecules present on Earth. TERM 22
Virus-Like Agents
DEFINITION 22
Sub-viral particles known as viroids. (smaller than viruses)
They are infectous RNA particles that cause diseases in
crop plants.
Not quiet viruses
Genome is 2 proteins long for quoting sequence and
cause a lot of damage
Their replication is not understood
TERM 23
TSEs
DEFINITION 23
Transmissible Spongiform Encephalopathies- Neurologic
diseases that can be transmitted to other animals of the
same species and possible to other animal species including
humans and the disease causes the formation of "sponge-
like" holes in brain tissue.Ex: mad cow disease
TERM 24
Prion
DEFINITION 24
-Discovered by Stanley Prusiner. He isolated an unusual
protein from scrapie-infected tissue (scrapie is a part of the
brain). He called the proteinaceous infectious particle a
prion.-The sequence of the protein was noted as PrP-the PrP
gene is primaraly expressed in the brain.
TERM 25
Protein only hypotheses
DEFINITION 25 -Predicts that prions are composed only protein and contain no nucleic acids-Also predicts that there are two types of prion proteins-Normal cellular prions (PrPc)are found on the surface of brain cells while abnormal prions (PrPsc) are found in scrapie, have different shape which cause TSEs.-TSEs may spread when infectous prions bind to normal prions causing the normal ones to change shape and become abnormal-Abnormal prions don't cause an immune response but death of an animal comes from the numerous nerve cell deaths
Laryngitis (inflammation of larynx)
Causative Agent: Cold virusesSigns & Symptoms: Hoarsenes,
loss of voiceTransmission: Resp. dropletsTreatment: Rest
voicePrevention/Control: Drinking plenty of water
TERM 32
Viral Infections of the Lower Respiratory Tract-
Influenza
DEFINITION 32 Influenza: Belongs to the Orthomyoxviridae famliy.-Has 8 different parts to its genomes each seperately incapsulated w/o it can't replicate of pass it on.-Contains 2 types of spikes:1. Hemagglutin (H): Helps the virion attach and penetrate to host cell2. Neuraminidase (N): Helps release virions from the host cell after replication and assembly***Every year a slighty different seasonal flu strain evolves based on changes to H and/or N spike proteins so there is a need for a new vaccine every year TERM 33
Outbreaks
DEFINITION 33
Epidemic: Regional (within our country) or specific area,
localePandemic: World-wive (Ex: Spanish Flu)*May be due to
an antigenic shift that we don't recognizeOutbreak is a term
used in epidemiology to describe an occurrence of disease
greater than would otherwise be expected at a particular
time and place.
TERM 34
3 Types of Influenza
DEFINITION 34 A: strikes ever year and causes most "flu" epidemics. Circulates in many animals (birds pigs humans like the H1N1, swine flu- pandemic. Divided into sub-types based on the Hand NB: also strikes every year but is less common than type A (only in humans not divided into subtypes)C: causes a mild respiratory illness but not epidemics, doesn't spread as well. TERM 35
Influenza can lead to..
DEFINITION 35 It becomes problematic when the virus spreads into the lungs causing pneumonia. This is especially true in infants, those 65+ years, and immunocompromised.-Guillan-Barre Syndrome: Occurs when the body mistargets the infection and instead damages its own peripheral nerve cells. -Reye Syndrome: Occurs in children who take aspirin to treat pain and fever (don't give kids aspirin!!!)
Antigenic Shift and Drift
SHIFT: Huge change in the genome. Can cause an epidemic
and usually the reason why we have outbreaks.DRIFT: Single
point mutations. Small changes to the genome.
TERM 37
Respiratory Suncytial (RS) Disease
DEFINITION 37 Caused by Respiratory syncytial virus (RSV)-Most common lower respiratory tract disease affecting infants and young children under 1 yr. similar to viral pneumnia-Transmitted by air droplets and virus-contaminated hands-Infects the bronchioles and aveoli of the lungs, causing cells to fuse together and intosyncytia-giant multinucleated cells-In adults it is seen as an influenza like syndrome with bronchitis and pneumonia in the elderly.-It is treated with Ribavirin-antiviral drug TERM 38
Parainfluenza
DEFINITION 38
Caused by human parainfluenza viruses 1 & 3-Infections are
milder than influenza and RS-Experience cold like symptoms-
Transmit through respiratory droplets and direct
contactThere is no specific therapy, but practice good hand
hygiene-(hMPV) are RSV-like viruses
TERM 39
SARS
DEFINITION 39 Severe acute respiratory syndrome is a viral respiratory disease of zoonotic origin caused by the SARS coronavirus (SARS-CoV). - Belongs to the Coronaviridae family. No effective treatment-It spreads in areas of high population through contact with an infect person or object upon which they have coughed on or sneezed, respiratory droplets- Bats are the reservoir, may be to high population of them together and their unique immune system. The civitcat is no longer it.- Long incubation period so an individual remains asymptomatic-Fever, headache, dry cough, difficulty breathing. TERM 40
Hantavirus Pulmonary Syndrome
DEFINITION 40 Cause by Hantavirus AKA Sin Nombre virus. Members of theBunyaviridae family. Seen in the 4 corners region (N.M, AZ, UT, CO) and Indian reservations-Reservoir is a deer mouse, virus shed saliva, urine and feces- The rodents have a decrease of health sanitary and hygiene-1 to 5 weeks after exposure symptoms of fatigue, fever and muscle aches begin.-Can lead to respiratory failure as lungs fill with fluid-Prevalent by eliminating rodent nests & minimizing contact-No vaccine, just supportive care
Roseola
-Caused by HHV-6. Symtoms include red rash on trunk and neck especially in infants/young children- Spread through contact with respiratory secretions or saliva.-It hides in the body until you have an immune system drop causing it to infect that person.-May reappear again if they got it when they were little.-HHV 6 belongs to a different genus of herpesviruses than HVS1-2- Prevention: no drugs yet, just avoid exposure to infected child TERM 47
Kaposi Sarcoma
(KS)
DEFINITION 47 Caused by HHV-8. (Only HHV8 and EBV are herpeviruses oncogenic agents)- Generates numerous blood cells (angiogenic). Seen in those with weakend immune system, like AIDS patients.- Symptoms:Dark lesions on skin.-Transmission: Contact, sexual and non-sexual- Treatment: Antiretroviral Therapy- Prevention/Control: Using anti-HIV medsTechinically, it's an STI. Seen on hands and feet, tumors within the blood vessels. TERM 48
Measles
DEFINITION 48 (aka Rubeola) Caused by Paramyxovirus-Tranmission occurs through respiratory droplets-Koplik spots are red patches with white grain-like centers that appear along the gum line. Cough, nasal discharge, high fever.-The red rash of measles appears about 2 days after the 2st evidence of Koplic spots. Rash covers entire body staring in hairline, eventually turning brown and fading- Prevention: MMR vaccine (Measles, Mumps, Rubella)- TERM 49
Mumps
DEFINITION 49 (aka Infectious parotitis)CausedbyParamyxovirus-Characterized by enlarged jaw caused by swollen salivary glands due to the blockage of ducts leading from the parotid glads.- Spreads through res. droplets or contact w/ contaminated objects-Orchitis: Swelling and damage to the testes in males=loss of sperm count and may cause sterility- The virus is found normally in our bodies, but most often seen in parotid glands-Treatment: MMR vaccine TERM 50
Rubella
DEFINITION 50 (aka German measles) acute mildly infectious disease-Caused by a virus of the Togaviridiae family.-Transmitted by resp. droplets or contact-Symptoms: Fever, pale-pink maculopapular rash.-Recovery is quick, but relapses can occur-Treatment: MMR vaccine- Congenital Rubella: When fetus is infected through the placenta (transplacental) leading to problems in the eye, ear, heart of the baby :(
Fifth Disease
(akaErythema infectiosum) Caused by Parvoviridae (B19)-
Spread through: Resp. droplets- Symptoms: fiery red rash on
cheeks, ears and trunk disappeaing within a few days.-The
disease is also referred to as slapped cheek syndrome,-Often
seen in children but also in adults. Their symptoms include
those similar to those of rheumatoid arthritis
TERM 52
Warts
DEFINITION 52
-Caused by Papovaviridae. Infection of HPV-Signs/Symptoms:
White or pink bening skin growth on hands and feet. Plantar
warts: soles of feet. No pain-Transmission: Contact-
Treatment: Freezing, minor surgery
TERM 53
Genital Warts
DEFINITION 53
- (aka condyloma) Its an STI. Symptoms of a highly
contagious STD caused by some types of human
papillomavirus (HPV) HPV-6 & 11- Symptoms: Small, flat,
flesh-colored bumbs anywhere in the genital region, anus.-
Transmission: Oral, vaginal, anal sex with someone w/ HPV-
Prevention: Abstaining from sexual activity, HPV vaccine
TERM 54
Cervical/Penile Cancer
DEFINITION 54
-Some strains of HPV are associated with cervical cancer.
May be transmitted to newborns-Theres a vaccine for some
HPV strains like gardacil (likely associated w/ cervical cancer)
Pap test-Caused by HPV 16 & 18.-Symptoms: Vaginal
bleeding and pelvic pain. Precancerous growth on the cervix
or peni-
TERM 55
Smallpox
DEFINITION 55 (aka Variolla=vessels) highly contagious and sometimes fatal- Caused by: Poxviridae.-Symptoms: Fever, macules (pink-red spots) that became papules (pink pimples), then fluid filled vesicles and pustules which break open and emit pus. First on the face then the bodyTransmission: Contact, droplets, fomites-Soviets found a strain and weaponized us (BIOTERRORISM)-Leave cintypitrol rash: huge disfiguring scars aka pocks.-Prevention: Vaccine, NO TREATMENT
Dengue fever- Viral Hemorrhagic Fevers*
Caused by: Dangue fever virus ( 4 types ) AKA break bone fever. flavivimosquitos: aegypti & alboptica -Symptoms: bleeding everywhere! & Dengue fever-Sudden high fever, headache, nausea, vomiting. If another of the 3 viruses enters the body causing: Dengue Hemorrhagic fever-skin hemorrhage=rash. face&extr Skin hemorrhage Dengue Shock Syndrome: Heavy bleeding, drop in blood pressure caused by (2) -Transmission of (1) is bite from mosquito (2) bite from mosquito w/ another dengue virus. No specific treatment available-Prevention: Avoiding mosquito bites in endemic areas TERM 62
Ebola/Marburg hemorrhagic fevers
DEFINITION 62 Caused by: Ebola and Marburg viruses of the Filovaridiae.-AKA "Key Lock Virus". Damages endothelial cells causing internal bleeding and hemorrhaging-Symptoms: Fever, headache, joint and muscle aches, sore throat, weakness. Internal bleeding and hemorrhaging. red eyes! hiccups-Transmission:Bite of infected fruit bat. Blood transfer of those who have it through cut, abrasion, or infected animal bite.-Treatment: No specific treatment available-Prevention: Avoiding dead animals and bats in outbreak areas-People handling their dead relatives may get this. TERM 63
Lassa Fever- Viral Hemorrhagic Fevers
DEFINITION 63 Caused by: Lassa fever virus of the Arenaviridae family- Symptoms: Severe fever, exhaustion, patchy blood-filled hemorrhagic lesions on throat-Transmission: Aerosol and direct contact with excreta from infected rodents-Treatments: Ribavirin- Prevention: Avoiding dead or infected rodents. Maintaining good home sanitary conditions.-The bush rat is the common diet for certain African natives TERM 64
Hep A- Infection of the GI Tract
DEFINITION 64 Caused by: Hepatitis A virus of the Pirconaviridae fambamSymptoms: Nausea, vomiting, low-grade fever. Enlargement of the liver and jaundice may followTransmission:Indirect through food or water contaminated by feces and raw shellfish (you ingest it and it affect your GI Tract) FECAL ORAL ROUTE -Treatment: No specific-Prevention:Hep A vaccine (3 diff types available for diff age groups. Doesn't last for a long time but, good for traveling) keep good hygiene TERM 65
Hep E- Infection of the GI Tract
DEFINITION 65
Caused by Hep E virus of the calciviridae fambam -
Symptoms: Nausea, muscle pain, low grade fever -
Transmission: Indirectly through water, Zoonosis ( FECAL
ORAL ROUTE )-Treatment: No effective treatment-
Prevention: Avoiding untreated waterNot in our notes
Viral Gastroenteritis (1 of 3)
- Caused by Rotavirus.-Symptoms: Diarrhea, nausea, vomiting, low grade fever, stomach cramping.-Transmission: Indirect through food or water. Contaminated things-Treatment: Self care, oral rehydration salt solutions-Prevention: Practicing good hygiene, avoiding shared items (2 vaccines)-Usually affects children. AKA "Winter Diarrhea"-occurs during this time (FECAL ORAL ROUTE) TERM 67
Viral Gastroenteritis (2 of 3)
DEFINITION 67
- Caused by: Norovirus-Symptoms:Nausea, vomiting, diarrhea, stomach cramping-Transmission:Indirect through food or water, person to person, fecal oral route, contact w/ infected surfaces -Treatment: Oral rehydration fluids-Prevention: praciting good hygiene, washing fruits and veggies-Common cause of non- bacterial gastroenteritis in adults. Seen in cruise ships. Highly contagious. "summer diarrhea". Dehydration is the main complication. TERM 68
Viral Gastroenteritis (3 of 3)
DEFINITION 68
3. Caused by: Enterovirus-Symptoms: Fever, mild rash, mild
URT illnesses-Transmission: indirect through food or water,
person to person-Treatment: ?-Prevention: Practicing good
hygiene , cleaning contaminated surfaces-AKA hand, foot,
mouth, disease. "24hr diarrhea"Not in notes
TERM 69
Rabies
DEFINITION 69 Caused by: Rabies Virus of the Rhabdoviridiae fambam-Symptoms: Tingling, burning, coldness at bite site,. Fever, headache, increased muscle tensions. Paralysis and hyndrophobia (fear of water) Patient becomes alert/agressive-Transmission:Bite from a rabid animal through bodily fluid-Treatment:Rabies immune globulin, rabies vaccine-Prevention: Avoiding rabid animals, thoroughly washing the bitten area, pre-exposure vaccination when needed- Has the highest mortality rate of any human disease-6 days-1yr before symptoms appear. Bite from doesnt ensure trans TERM 70
Polio
DEFINITION 70 Caused by: Poliovirus (AKA Poliomyelitis)-Symptoms: Often no signs or symptoms-Transmission: Fecal-oral route (contaminated water or food)-Treatment: Supportive treatments-Prevention: Polio vaccine, practicing good hygieneSymptoms may only be nausea, vomitting, cramps, but sometimes the virus pass through the bloodstream and localize on the meninges where they cause menengitis. And may cause paralysis.
