Lec 5: Diseases of the 21st Century Flashcards
(258 cards)
1
Q
What is the smallest known infective agent?
A
Virus
2
Q
What are the characteristics of a virus? (5)
A
- Does not have a cellular organization
- Contains only one type of nucleic acid
- Obligate intracellular parasite
- Lacks enzymes necessary for protein and nucleic acid synthesis
- Unaffected by antibacterial antibiotics
3
Q
What term refers to extracellular infectious virus particle?
A
Virion
4
Q
What is the size of viruses? (compared to bacteria)
A
Much smaller than bacteria
5
Q
Why are viruses referred to as Filterable and Ultramicroscopic?
A
▪ Filterable viruses since they can pass through filters unlike bacteria
▪ Ultramicroscopic, as they were too small to be seen under the light microscope
6
Q
A virus cannot be categorized as prokaryote or eukaryote because it does not have a?
A
cellular organization
7
Q
What do you call a virus outside the host cell which can’t do anything and is dormant and inactive?
A
Virion
8
Q
A virus could be RNA or DNA but not?
A
not both
9
Q
When can a virus be activated or when does it leave the dormant state?
A
When it interacts with a host cell
10
Q
What is the capability of a virus to target/infect a host cell?
A
Host Tropism
11
Q
When a virus gets inside body it does not infect directly, what does it do?
A
it chooses a certain host cell
12
Q
What are the target host cells of HIV and HBV?
A
HIV - CD4 T cells
HBV - Hepatocytes in liver
13
Q
When talking about the morphology of the virus, what must you consider?
A
The size and the shape
14
Q
What is the unit of measurement of virion size and how does it compare to a bacteria?
A
unit of measurement of virion size is nanometers
- viruses are much smaller than bacteria (micrometers)
15
Q
What makes the filterbale viruses a disadvantage in the medical setting?
A
BSC don’t have the ability to filter them through the hepa filter
16
Q
Viruses are Ultramicroscopic, as they were too small to be seen under the light microscope. This is true except for what type of virus?
A
except for the LARGEST DNA VIRUS: Poxvirus if stained properly
- for the rest you can use the ELECTRON MICROSCOPE
17
Q
What is the smallest and largest DNA virus?
A
Smallest: Parvovirus
Largest: Poxvirus
18
Q
What is the smallest and largest RNA virus?
A
Smallest: Picornnavirus
Largest: Paramyxovirus
19
Q
What are the four shapes of a virus?
A
- Helical (or cylindrical)
- Isometric
- Enveloped
- Head and tail
20
Q
What virus shape is typical among many plant viruses such as tobacco mosaic virus or TMV?
A
Helical
21
Q
What is the shape of your poliovirus and herpes virus?
A
Isometric or icosahedral
22
Q
What is the characteristic of an enveloped shape of a virus?
A
it has glycoprotein spikes that protrude on the plasma membrane
23
Q
what shape of the virus have membranes derived from the host cell that surrounds the capsid such as hiv and coronavirus?
A
Enveloped
24
Q
Identify
Viruses with this shape in fact bacteria and have a head-like icosahedral viruses and a tail-shaped like helical viruses. What’s an example of this?
A
Head and tail
ex: Bacteriophage
25
What is the shape of your human rhinovirus or HRV 14?
Isometric or Icosahedral
26
What is the difference between enveloped and non-enveloped virus structure?
Enveloped
- has glycoprotein spikes
- Has Genome, capsid, nucleocapsid, spikes, tegument, envelop
Non-enveloped
- naked
- do not have glycoprotein spikes
- Only has GENOME, CAPSID, and NUCLEOCAPSID
27
What structure of the virus is also called the nucleic acid core which could either be RNA or DNA but not both?
Genome
28
what refers to the protein layers covering the genome of a virus?
capsid
29
What refers the terms used to describe the combination of genome and capsid as a structure of a virus?
Nucleocapsid
30
In an envelope virus, what must be present in order for the virus to infect a host cell?
Glycoprotein spikes or Peplomers
31
# Identify
This refers the matrix separating envelop from nucleocapsid
Tegument
32
what is the external glycoprotein or lipid that is covering the nucleocapsid taken from the host?
Envelop
33
what structure of a virus is where the spikes protrude?
Envelop
34
Which type of virus is more resistant to changes in environment?
Naked virus
35
The naked virus is more resistant to extreme environmental conditions like?
pH, dryness, heat, simple disinfectant
36
What are examples of naked viruses?
Norovirus, Enterovirus, Adenovirus, Rhinovirus
37
Why are naked viruses considered more virulent?
more virulent because they cause POST-CELL LYSIS: once done replicating and go to other cells, the cell where they replicated will die
38
How are naked viruses and envelope viruses transmitted?
Naked: by fecal-oral route
Enveloped: by respiratory inhalation, sexual or parenteral contact, or perinatal contact
39
What happens to enveloped virus when they go out of the host cell?
They die
40
what are the functions of peplomers?
1. Mediate attachment
2. Attach to receptors
3. Enzymatic activity
4. Major antigens: for protective immunity of the virus
41
what are the functions of capsid?
1. Protection
2. Binding sites
3. Facilitates assembly and packaging of viral genetic information
4. Vehicle transmission
5. Host defense
6. Provides structural symmetry to the virus particle (shape of the virus)
42
What type of genome does HIV have?
RNA
43
What viral glycoproteins are found in the envelope of the HIV structure and what is/are their function?
- gp120 and gp41(knob-like)
- function: for host cell attachment
44
What protein protects the 2 ssRNA strands in the HIV structure?
p24 or the CORE PROTEIN
45
What are the 3 enzymes found inside the p24 or the Core protein that protects the ssRNA strands of an HIV virus?
1. p10 (protease)
2. p32 (integrase)
3. p64 (reverse transcriptase)
46
What enzyme inside the HIV virus integrates the double stranded DNA, that resulted from the uncoating of genetic material, to the host material? (reason why the virus can order around the host cell)
p32 or integrase
47
What is the most important enzyme found only in HIV?
p64 or reverse transcriptase
48
# Identify
Without this, there is no way for host cell to follow the instructions of the virus - dli ka replicate ang virus of HIV
p64 or reverse transcriptase
49
What is the function of the p64 enzyme in HIV?
transcribes viral RNA to a double-stranded DNA - conversion of viral genomic RNA to double-stranded DNA
50
HIV belongs to what genus and family?
Belongs to the genus ***Lentiviridae*** of the virus family ***Retroviridae***
51
What virus is described as a spherical particle, 100-120 nm in diameter?
HIV
52
What is the #1 cause of death for people (bet. 20-35 yrs. old)?
HIV - 1
53
How is HIV-1 transmitted?
transmitted thru:
- unprotected sex
- contaminated blood or blood products
- contaminated needles, or perinatal
54
HIV-1 is isolated from?
- mononuclear cells,
- plasma,
- semen,
- cervical/ vaginal secretions,
- saliva (barrels since its hypotonic and has salivary enzymes)
- tears,
- urine,
- breast milk,
- CSF,
- lymph nodes,
- brain, and
- bone marrow.
55
How is vertical transmission of HIV-1 possible?
- from mother to child in utero
- during delivery
- breastmilk
56
HIV-2 is transmitted through?
- blood products
- sexual contact, or
- from mothers to infants
57
Majority of HIV cases are transmitted through?
Intimate sexual contact (either vaginal or anal intercourse)
58
In the US, the largest number of cases is the result of ___________. But 85% of HIV is attributed to _____________
- 85% of HIV is attributed to heterosexual contact
- in US, the largest number of cases is the result of homosexual contact
59
What can increase the likelihood of transmission of HIV?
Presence of other sexually transmitted
diseases such as syphilis, gonorrhea, or
genital herpes
60
In male to male, if sex is rough, integrity of rectum is violated - abrasions can be a portal of entry of the virus. for vaginal intercourse - cervix is thin and prone to abrasions; and foreskin for males. Why do abrasions cause infection aside from being a portal of entry?
If there is abrasion - there will be disruption of the protective mucus membrane and increase in immune activation in the genital area (when body detects foreign antigen - the immune system attack and create antibodies)
61
PARENTERAL EXPOSURE TO
INFECTED BLOOD OR BODY FLUIDS happens when there is?
- Sharing of contaminated needles by IV drug users
- Blood transfusion or the use of clotting factors by hemophiliacs
- Occupational injuries with needle sticks or other sharp objects
- Mucous membrane contact in healthcare workers exposed to infectious fluids
- Transplantation of infected tissues
62
Perinatal transmission of HIV has been markedly decreased through?
- HIV screening during pregnancy
- Administration of antiretroviral drugs to HIV positive pregnant women and their newborn babies
- Use of infant formula by HIV-infected mothers
63
How is HIV attachment to a susceptible host cell mediated?
Mediated through the host-cell CD4 antigen
(receptor for HIV) by binding the gp120 and gp41 on the outer envelope of the virus
64
What are the main target cells of HIV?
T helper cells (CD4)
65
What other cells have CD4 molecules?
- monocytes,
- macrophages,
- dendritic cells,
- Langerhans cells,
- microglial cells of the brain
66
What is required for HIV to enter the host cell?
Requires chemokine receptors that promote fusion of HIV envelope with the plasma cell membrane
67
What are the chemokine receptors required for the fusion of HIV envelope wiith the plasma cell membrane?
- CXCR4 for T lymphocytes
- CCR5 for macrophag
68
What happens during the uncoating of viral particle in HIV transmission?
- Exposed viral genome acted upon by RT producing cDNA from the viral RNA
- cDNA is incorporated to the host cell’s genome known as provirus
- Viral DNA is transcribed into genomic RNA and mRNA (transported to the cytoplasm)–
- Translation of mRNA occurs, with production of viral proteins and assembly of viral particles
69
How does the HIV virus replicates to other host cells?
virus leaves the host cell after replication through acquiring an envelope if mufuse ang viral particle pagawas sa host cell and then it will infect another host cell
70
The signs and symptoms of HIV are characterized by?
a progressive decline of the immune system
71
What are the 3 stages of the clinical symptoms of HIV?
1. Primary/Acute/Early Infection
2. Clinical latency
3. Final stage (AIDS)
72
What symptom stage in HIV is characterized by a rapid burst of viral replication and high levels of circulating virus in blood (viremia)?
Primary/Acute/Early
Infection
73
When does an HIV patient experience HIV beginning to disseminate to the lymphoid organs like the spleen and bone marrow?
| symptomatic stage
Primary/Acute/Early Infection
74
What are the flu-like symptoms exhibitted by the patient during Primary/acute/Early infection of HIV and when do these appear?
patient exhibits flu-like symptoms:
- fever,
- lymphadenopathy,
- sore throat,
- arthralgia,
- myalgia (body malaise),
- fatigue,
- rash, and
- weight loss
symptoms appear 3-6 weeks after initial infection - resolved within a few days to few weeks - so you feel healthy again
75
T or F. Some patients are asymptomatic during the primary/acute/early infection
T
76
What symptomatic stage in HIV infection is characterized by a decrease in viral loads of blood, disappearance of viremia, virus will be cleared in the circulation?
Clinical Latency
77
In what symptomatic stage of HIV is when symptoms Suddenly disappear but the virus is still present in the plasma in lower levels and more so in lymphoid organs?
Clinical Latency
78
What is the time period of Clinical latency as a symptomatic stage in hiv infection?
period latency can vary widely but has a median length of 10 years - but if treated early then extend to at least 20 yrs or more
79
What symptomatic stage in HIV infection is characterized by profound immunosuppression and resurgence of viremia?
Final stage (AIDS)
80
What clinical symptom of HIV is chracterized by the presence of life-threatening infections and malignancy and neurological symptoms - resulting in the ability of virus to infect microglial cells in brain?
Final Stage AIDS
81
what is the hallmark of HIV infection?
severe T-cell depletion; result of presence of opportunistic infections and malignancies
82
In hiv infection, how would you know if there is severe depletion of CD4 T cells?
- to know how severe the depletion is - perform CD4 T cell enumeration test (count is less than 200 cells/microliter - SEVERE)
83
What symptoms does HIV infection show in these parts?
- Lymph node
- Respiratory system
- Muscle
- Joints
- Head/Brain
- Skin
- Digestive system
- Nail
- Body mass
- Lymph node (swelling)
- Respiratory system (dry cough, pneumonia, sore throat)
- Muscle (pain)
- Joints (pain)
- Head/Brain (headache and difficulty concentrating)
- Skin (rashes, fever, night sweats)
- Digestive system (nausea, vomiting, ,diarrhea)
- Nail (thickening and curving)
- Body mass (weight losss and fatigue)
84
what is the specific purpose of treatment in HIV infection?
PUPOSE: not to cure but to decrease viral load and slow down replication of virus inside the body
85
What are the general treatment methods imposed into HIV patients?
▪Involves supportive care of the infection and malignancies
▪ Administration of antiretroviral drugs
86
T or F. When treating an HIV infection, it is recommended to only use one antiretroviral drug
F. - Acc to Stevens, it would be more efficient if we use 2 or more combination of ARVs
Treatment with multiple drugs is more effective in killing HIV than treatment with a single drug
87
What is an example of an ARV and what is its goal?
**HAART** (highly active antiretroviral therapy)
▪ Goal of HAART: to reduce the patient’s HIV viral load and boosting patient’s level of
immunocompetence
88
Can HIV patients develop resistance to ARVs?
YES - some patients di na ma extend ang lifespan because nidevelop nag resistance to the ARVs
89
What laboratory tests can be done to assess HIV infection?
1. CD4 T-cell Enumeration
2. HIV Antibody Detection
- Screening tests (ELISA)
- Rapid tests (test kits)
3. Confirmatory Test (Western Blot) or Immunoblot
4. Nucleic Acid Testing (NAT)
5. Cultivation of Viruses
90
What laboratory test is used routinely to monitor the effectiveness of ARV therapy?
CD4 T-cell enumeration
91
CD4 T-cell enumeration for HIV patients is recommended to be performed every how many months? and why?
Recommended to be performed every 3-6 months
- to guide physicians in determining when antiviral therapy should be initiated
- whether a change in therapy is necessary
- and if prophylactic drugs for certain opportunistic infections should be administered
92
What is the Ideal screening test for HIV antibodies in laboratories that perform large-volume batch test?
Screening test (ELISA)
HIV Antibody Detection
93
What does a screening test imply about an HIV patient?
meaning not 100% sure that you have HIV - need to progress to CONFIRMATORY TESTING
94
What are the drawbacks of HIV Antibody Detection specifically screening tests like ELISA?
- Require complex instrumentation and skilled personnel with technical expertise
- Typically have a turn-around time of a few days
- Sample: Serum
95
What is the Standard screening method for HIV detection?
ELISA (Enzyme-Linked Immunosorbent Assay)
96
What should be done in ELISA test when a sample yields a positive result? If two out
of the three specimens are reactive?
- When a sample yields a positive result, it should be retested in duplicate by the same ELISA test.
- If two out of the three specimens are reactive, then the results must be confirmed by a more specific method, usually Western blot.
97
What HIV Antibody Detection method is Ideal for use in resource-limited settings in
developing nations and Highly sensitive, simple to perform, and provide results in less than 30 minutes?
Rapid tests (test kits)
98
What samples and principle is/are used in rapid test kits for HIV antibody detection?
**Samples:** serum, plasma, whole blood, and oral fluid
**Principle:** lateral flow or flow-through
immunoassays that produce colorimetric (red bands) reaction
99
Aside from NAT, what is another confirmatory test done for HIV detection and what does a negative, positive, or indeterminate result imply?
**Western blot or Immunoblot**
- **Negative**: if either no bands are present or if none of the bands present correspond to the molecular weights of any of the known viral proteins.
- **Positive:** if at least 2 of 3 bands are present: p24, gp41, and gp120/gp160
- **Indeterminate:** Presence of
the characteristic bands but do not meet the criteria for a positive test result
100
Is the HIV virus detected immediately after sexual intercouse? What can the patient do if he/she is suspecting his/her partner?
The virus during replication is not detected dayon within 24 hrs after sexual intercourse because some undergo an incubation period or window period
- Patient pede mutake ug prophylaxis: medication given to person para di mupadayon ug daghan/sulod ang virus sa host cell
101
What is the standard confirmatory test for HIV according to San Lazaro Hospital?
Nucleic Acid Testing (NAT)
102
# Identify
This refers to Amplification methods that increase the number of HIV RNA copies in test samples to detectable levels
Viral Load Assays
103
What is required in the cultivation of HIV?
Requires susceptible host cells capable of replicating them and a BSL 3 or 4
104
What are the 3 methods of HIV cultivation?
3 methods:
- animal inoculation (monkey or mice)
- embryonated eggs (hen egg)
- cell culture
105
What airborne virus can spread through small droplets of saliva like coughing and sneezing belongs to the family Coronaviridae?
SEVERE ACUTE RESPIRATORY SYNDROME
106
When did SARS first appear?
First appeared in November 2022 in the Guangdong province of Southern China
- Feb 21, Metropole Hotel 9th floor; symptomatic; infected 12 guests
Other info:
▪ Feb. 2003- reported cases were observed in mainland China, Hongkong, Singapore, Taiwan, and Canada.
▪ WHO issued global alert in March 2003 considering SARS as a worldwide threat
▪ 8,000 SARS cases reported in 32 countries
107
The first few infected patients from China flew to to other countries like?
Vietnam, Singapore, Canada, Ireland, US
108
During the start of the SARS spread, Some patients became seriously ill and died of respiratory distress syndrome. What was the mortality rate?
Mortality rate 5% (much higher in susceptible populations)
NO EFFECTIVE ANTIVIRAL DRUGS
109
What Family of RNA viruses have crown-like spikes on their surface?
CORONA VIRUSES
110
What are the Three highly pathogenic and
deadly human coronaviruses?
▪ SARS-CoV (2003)
▪ MERS-CoV (Middle East Respiratory syndrome)
▪ SARS-CoV-2 (CoViD)
111
Why are corona viruses generally considered highly infectious?
because high levels of virus
found in sputum --> blood --> feces
112
What cornavirus is transmitted through Close person-to person contact through inhalation of air droplets or by contacting with contaminated surfaces of devices?
SARS-CoV
113
What coronavirus is transmitted through human to human transmission occurred in close contacts(direct contact and spread by droplets)?
SARS-CoV-2
114
What coronavirus is transmitted through
* Contact with infected dromedary camels
* Human-to-human transmission
* Contact with stool, vomitus, urine, serum, and CSF of patients infected
MERS-CoV
115
How is SARS generally transmitted? (3 ways)
***Transmission: close person-to-person contact***
**1. Respiratory droplets**
* coughing, sneezing
* droplets propelled up to 3 feet
* deposited on mucous membranes (mouth, nose, and eyes) of persons nearby
**2. Contaminated hands**
**3. Mechanical vectors** (door handles, towels, etc.)
116
How long can SARS survive in the environment and what are the incubation periods of each type of SARS?
**Virus can survive 3 hours in the environment**
Incubation period:
❑ SARS-CoV: 4 days
❑ SARS-CoV-2: 2-14 days
❑ MERS-CoV: 5.2 days
117
What are the symptoms of SARS and what specific organ does it target?
SARS - targets the lungs
Symptoms:
- coughing
- Fever (38 or more)
- flu-like symptoms such as joint pain and malaise
- headache
- sore throat
- shortness of breath and diffuclty of breathing due to pneumonia
- low white cell count
118
Why do SARS patients experience leukopenia?
LEUKOPENIA is brought about by the body creating antibodies that target WBCs, immune system forms immune complexes that target WBC
- patient prone to infection
119
The LETHAL FORCE OF SARS or symptoms generally follows a clinical pattern (2 stages). what are these?
**1. Stage 1**:
- Flu-like symptoms (fever, fatigue, headache, chills, myalgia, malaise, anorexia) begin 2-7 days after incubation (4) and last for 3-7 days
**2. Stage 2:**
- Progressing of stage 1;
- characterized by lower respiratory tract phase (drying cough, dyspnea, progressive hypoxemia, respiratory failure, some require mechanical ventilator)
120
SARS symptoms start with Starts with _______(4)
▪ At ____ days, ______ occurs: _____ (3)
▪ Severity of SARS is _________
▪ Virus causes ____ damage
Starts with **chills, fever, mild respiratory symptoms, and diarrhea**
▪ At **3-7 days**, **lower respiratory tract** infection occurs: **cough, shortness of breath, and evidence of pneumonia**
▪ Severity of SARS is **variable**
▪ Virus causes **lung damage**
121
What symptom of SARS is characterized by accumulation of fluid in alveolar sacs?
pneumonia
122
SARS causes lung damage because the lungs become what?
Lungs harden or **calcify**, it cannot expand then maglisod ginhawa;
123
What is the usual cause of death of SARS patient and what factors dictate the extent of which they can recover?
- USUAL CAUSE OF DEATH: **respiratory distress**
**RECOVERY**
- depends on person's immune system
- patients aged 40 and above are more susceptible and prone to infection
124
What are the 3 major effect of SARS virus (Pathology)?
1. Virus causes damage to capillaries and cells lining the alveoli (air sacs)
2. Impaired formation of surfactant
3. Leakage of protein-rich fluid into alveoli
125
What lubricates the alveoli, preventing its walls to tick during breathing?
Surfactant
126
What is the protein-rich fluid that leaks into the alveoli caused by SARS virus and how does it affect gas exchange?
**Fibrinogen**
- a clotting protein usually found in the blood
- its leakage creates a clot which coats the surface of the air passages preventing the diffusion of gases (O2 and CO2) between air passages and the pulmonary capillary
127
What is the main reason why some patients die from SARS virus?
RESPIRATORY DISEASE SYNDROME
128
What is the specific term used to refer to build up of fluid in the alveolar sac?
Inflammatory exudation (in alveoli and interstitial spaces)
129
What are the clinical features of SARS in terms of Lung Pathology?
- Inflammatory exudation in alveoli and interstitial spaces = **fluid in lungs**
- Monocytic and lymphocytic infiltration of lung tissue = **immune cells in lungs**
- Hyperplasia of alveolar epithelial cells/fibrous tissue = **excessive proliferation of cells**
- Fibrosis of lung tissue =**excessive fibrinogen causes hardening lungs**
130
Hyperplasia of alveolar epithelial cells/fibrous tissue due to SARS leads to?
excessive proliferation cells (immune cells)
131
What immune cells are present in the lungs when a patient has SARS?
- monocytes
- lymphocytes
body's response to the pathogen; since it is a virus then lymphocytes are active; increase in number
132
Fibrosis (calcification) of lung tissue can lead to death caused by?
Respiratoruy distres syndrome
133
What is the most important question for the future of eradicating SARS?
whether SARS can be eliminated or eradicated from its new human host.
134
In Eradicating SARS, WHO mandates 3 precise requirements to be met:
1. Use of vaccines
2. Easy to use diagnostic tools
3. Chain of human-to-human transmission must be broken
135
The easy to use diagnostic tools for eradication of SARS must be/have? (describe)
**sufficient sensitivity and specificity** to detect levels of infection that can lead to transmission of disease
136
What is essential to the life cycle of the causative agent of SARS or any other viruses? what complicates the eradication of these viruses?
Infection of humans
Existence of an animal reservoir complicates the eradication
137
What must the control and intervention for SARS be in order to achieve eradication at a global level? What are the current control measures avaibale for SARS?
- To achieve eradication at a global level - the control and intervention must be **safe, simple, and affordable**
- **CURRENT CONTROL MEASURES for SARS**: case detection and isolation, tracing and follow up of contact, and quarantine are effective but time-expensive
138
The 2002-2003 epidemic of SARS is probably the most thoroughly studied example of?
an animal virus “jumping” into humans
139
Epidemiological investigations suggest an animal origin of the SARS virus. What are these animals?
- Virological and serological studies indicated that **masked palm civets** together with 2 other wildlife animals were infected with SARS-CoV
- recently the **horseshoe bat** has been identified as a natural reservoir of SARS-like Coronaviruses
140
What determines which species of cells the SARS virus can infect?
**SARS viral glycoprotein** (spike protein on viral surface) determines which species of cells the virus can infect
141
How does SARS infect a cell?
- Spike protein (on virus) binds **transmembrane ACE protein** on human cell surface
- Proof that the transmembrane ACE protein on cell surfaces is the **receptor for SARS** virus binding
- addition of soluble ACE protein or addition of anti-ACE antibodies prevents the SARS virus from binding
142
What prevents the SARS virus from binding to the cell surface?
- absence of soluble ACE protein or anti-ACE antibodies prevents the SARS virus from binding
143
WHY HAVE WE NOT SEEN REOCCURRING SARS EPIDEMICS FROM 2003 TO 2019?
- The S protein of SARS-CoV is composed of 1255 amino acids and it's responsible for the viral attachment and entry into the host cell. **Mutations in the viral spikes of the virus** can lead to changes in the conformation of the spikes resulting to the viruses inability to attach to the host cell receptor **(POOR FIT)**
144
Describe the mutations that occured in the SARS virus spike proteins in 2002-03 and 03-04
**In 2002-2003: PERFECT FIT** between viral spike protein and human cell receptor protein
**In 2003-2004**: 2 amino acids mutated, **POOR FIT**
145
What are the LESSONS FROM SARS
(APPLICABLE TO ANY NEWLY EMERGING
INFECTIOUS RESPIRATORY DISEASE)?
- Only **one individual** is required for an outbreak
- The SARS virus is sufficiently transmissible to cause a very large **epidemic if unchecked.**
- The **(unsuspected SARS patients carriers)** will be the greatest challenge in medicine if SARS cannot be eradicated
146
What term refers to individuals who harbor the SARS virus but do not show symptoms of the infection - they can freely transmit the infection without the knowledge of the person?
Carriers
147
What was the suspected origin of SARS outbreak in 2003?
CIVET (Masked civet)
- suspected as the origin of SARS outbreak in 2003
- confirmed as the direct origin of mild symptoms SARS cases in 2004
- bats were also known as reservoirs of zoonotic viruses including rabies and EBOLA
148
Where and when did the first US SARS vaccine trial opened?
FIRST U.S. SARS VACCINE TRIAL OPENS AT NIH (National Institutes of Health) MONDAY, DECEMBER 13, 2004
149
Researchers from NIH have used the SARS corona virus to develop two different types of
vaccines that are now in human clinical
trials. What are these?
1. Inactivated virus
2. SARS spike DNA (gold) inserted into DNA plasmid
150
What type of SARS vaccine in human clincal trials is less virulent since it is a weakened form of the virus and results to the immune system creating antibodies to SARS virus surface proteins?
Inactivated virus
151
What type of SARS vaccine in human clinical trials creates immunity through:
- Plasmid gets into human cells
- Cell will transcribe the SARS virus spike DNA into mRNA into protein
- Body will produce immune response to viral spike protein
SARS spike DNA (gold) inserted into DNA plasmid
152
What are some prevention measures for SARS virus?
a. **Genetically engineered antibodies** which are effective in blocking the virus.
b. Public health officials established **infection-control measures:** those infected must be isolated in their homes or in hospitals
c. Caregivers follow **strict procedures**
d. WHO issued **travel advisories**
153
Influenza virus belong to what family?
Orthomyxoviridae
154
What is the genome and shape of an Influenza virus?
RNA type and enveloped
155
What influenza types cause seasonal epidemics of disease/flu season?
Influenza A and B
156
What virus is the only one known to cause flu pandemic?
Influenza A
157
What virus generally causes mild illness, not thought to cause human epidemics?
Inluenza B
158
What are the 2 important glycoproteins found in Influenza viruses?
hemagglutinin (H or
HA - triangular) and neuraminidase (N or NA - mushroom shape)
159
Influenza viruses are divided into subtypes based on what?
based on the 2 proteins on the surface of the virus
160
What do you call the rod shaped spikes that play crucial role in the early stage of viral infection of Influenza and is responsible for binding the virus to the cell surface receptor, it mediates liberation of the viral genome into the cytoplasm through membrane fusion?
Hemagglutinin
161
What facilitates the release of mature virions from infected cells and assists viral movement through mucus to adjacent cells of Inlfuenza viruses?
Neuraminidase
162
How many major subtypes do Influenza viruses with Hemagglutinins have?
18 major subtypes
163
How many major subtypes do Influenza viruses with Neuraminidase have?
11 major subtypes
164
What disease is caused by two main types of human flu viruses: Influenza A and Influenza B. The virus affects the upper respiratory organs?
Human flu
165
166
What is the mode of transmission of human flu?
- Person to person contact with respiratory droplets produced when the patient coughs or sneezes
- Contaminated hands with influenza virus
167
What are the signs and symptoms of the Human Flu?
- High fever,
- body aches,
- headache,
- severe malaise,
- dry cough,
- sore throat, and
- runny nose
168
What flu is also known as bird flu caused by Type A Influenza seen in seabirds, shorebirds, and other wild fowl, and does not normally infect humans but have SPORADIC human infections occuring?
Avian flu
169
What virus killed 6 people out of 18 sick in 1997, Hongkong with the variant H5N1?
Avian Flu
170
What variant of the avian flu caused death in Europe/Easter USA in 2003-2004?
H7
171
Why do you need to specifiy the variant of Influenza virus?
- SPECIFY the variant because the 2 glycoproteins have many subtypes
172
What disease can be spread when wild birds contaminate ponds and fields with fecal droppings containing the virus?
Avian flu
173
Avian flue infects though what organ/body systems?
Respiratory and nervous
174
What are the symptoms of Avian flu?
SYMPTOMS similar to flu infections like fever, - cough
- sore throat, and
- muscle aaches
- pneumonia,
- kidney failure, and
- other related complications may also arise
175
How does backyard poultry spread bird flu to people?
1. Direct contact
2. Contaminated surfaces
3. Bird flu virus in the Air (in droplets or dust)
176
You can get bird flu through direct contact or exposure to what?
- saliva
- mucus
- feces from infected birds
177
What is the respiratory disease of pigs caused by type A influenza virus (H1N1) that regularly causes outbreaks of influenza in pigs?
Swine Flu
178
What variant of influenza is found in swine flu?
Influenza A (H1N1)
179
Symptoms of this disease include fever, depression, coughing (barking), discharge from nose or eyes, sneezing, breathing difficulties, eye redness, and going off feed. What is this disease?
Swine flu
180
What is something unique about influenza in terms of their genetic make up?
- Antigenic Drift
- Antigenic Shift
181
What do youca ll the process where INFLUENZA A and B alter hemagglutinins and neuraminidase antigens that are found on their plasma membrane, resulting in a production of an anti-genetically different virus annually?
Antigenic Drift
182
What makes the formulation of a vaccine for Influenza A challenging?
Influenza A undergoes seasonal antigenic drift every year - makes formulation of effective vaccine challenging
183
Antigenic Drift of inluenze results to?
minor antigenic change that causes local outbreaks of influenza every 1-3 yrs
184
# Identify
This process involves a change in the viral genome and only occurs with influenza A viruses; results in a major antigenic change, which causes periodic worldwide outbreaks. This occurs when a circulating influenza A strain acquires a novel subtype which occurs when 2 different strains simultaneously infect a single host
Antigenic Shift
185
During viral replication, what happens to the segmented genome of the influenza virus?
It may reassort, mixing segments from the different strains during the infection, resulting in a unique antigenic combination (ANTIGENIC SHIFT)
186
What influenza dieseases with reassortment of their genes have been the cause of several pandemics throughout history and what acts as their vessel for reassortment?
**AVIAN INFLUENZA** and **HUMAN INFLUENZA** reassortment of genes have been the cause of several pandemics throughout history; often, the **swine** acts as the vessel for these reassortment events (they can infect and replicate in the swine respiratory epithelium)
187
When can a pandemic occur?
A pandemic can occur if **virus is able to sustain human-to-human transmission**. It is a virulent human influenza virus that causes a global outbreak of serious illness in which there is little natural immunity and has sustained person-to-person transmission; it often results in high rates of human mortality with social and economic consequences
188
What are the prevention measures of Influenza?
a. Destruction of infected birds
b. Isolation of those infected
c. Antiviral and vaccines to protect people
d. Proper cooking of food
OTHER WAYS
- washing and drying our hands
- covering mouth and nose when sneezing
- use disposable tissues and throw properly
- stay at home when not feeling well
- avoid close contact with sick people
- avoid touching eyes, nose, or mouth - these are portals of entry
189
# Identify
This term refers to the destruction of infected birds as a prevention measure of Influenza
Culling
190
What is the best way to prevent influenza?
**ANTIVIRAL AND VACCINES**
- annual vaccination is recommended since it goes away over time; it is less effective in older people but it reduces complications and death
191
What should you do when cooking in order to kill influenza virus?
Increase temp and properly cook the food (ex: poultry products)
192
What term is used to refer to the deliberate release of viruses, bacteria, or other germs (agents) used to cause illness or death to humans or animals?
Bioterrorism attack
193
What are the agents of bioterrorism?
a. Typically found in nature
b. Spread: thru air, water, or food
194
What method is used in bioterrorism in order to increase the microorganism's resistance to current medicines or to increase their ability to spread in the environment?
GENETIC MODIFICATION/ENGINEERING
195
What is an example of a virus that can be spread from person to person? Virus that cannot be spread from person to person?
- **Smallpox**: spread from person to person
- some like **Anthrax**: cannot be spread from person to person
196
The microscopic spores of Anthrax could be placed in what materials?
powders, sprays, food, and water
197
What are the other names for Anthrax?
- Woolsorters Disease
- RAgpicker's Disease
198
What serious disease is caused by Bacillus anthracis, a bacterium that forms spores?
Anthrax
199
T or F. Anthrax is caused by a gram negative bacilli
F. gram positive
200
What possible disease could be acquired from handling contaminated animal fibers, hides, and other animal products?
Anthrax
201
What is the most suitable environment of the Bacillus anthracis?
- optimal growth temp is 37 deg C; unable to grow above 43 deg C
- survive best in soil with rich organic matter with high calcium levels and slightly alkaline pH
202
IN anthrax, what is a spore?
A spore is a cell that is dormant (asleep) but may come to life with the right conditions.
- spores become resistant to harsh environmental conditions such as heat, dehydration, pH, desiccation, chemicals, and irradiation
203
HOW DO YOU GET ANTHRAX?
- from animals
- from bioweapons
204
Anthrax is not known to spread from one person to another so how is it acquired?
Human infection thru:
- handling products from infected animals or by
- breathing spores from infected animal products (like wool)
- eating undercooked meat from infected animals (GASTROINTESTINAL ANTHRAX)
205
How did Anthrax spread as a bioweapon in US?
United States in 2001, spread through the postal system by sending letters with powder containing anthrax. This caused 22 cases of anthrax infection & some fatalities
206
What are the types of anthrax?
There are four types of anthrax:
1. skin (cutaneous)
2. digestive (gastrointestinal)
3. lungs (inhalational)
4. injectional
207
What type of anthrax - emerged more recently and is recognized as an additional form of clinical infection as a result from direct injection of spores into tissues during the administration of drugs of abuse
- common among IV drug abusers?
Injectional Anthrax
208
What is the symptom seen in cutaneous anthrax?
black eschar
209
What is the most common naturally occurring type, comes from handling contaminated animal product - such as meat, wool, or hides?
Cutaneous anthrax
210
Black eschar begins as a small bump that progresses into a larger blister in ____days. About ____% of untreated cases can result in death
Black eschar begins as a small bump that progresses into a larger blister in **1-2 days**. About **5-20%** of untreated cases can result in death
211
What anthrax can occur when eating raw or undercooked contaminated meat? What are its initial signs?
Gastrointestinal (“stomach”) anthrax
- Initial signs are:
- nausea,
- loss of appetite,
- vomiting, and fever
- followed by severe abdominal pain,
- vomiting blood, and
- severe diarrhea.
212
What type of anthrax is very rare and does not have documented cases in the 20th century in the US but death results in 25-60% of the cases?
Gastrointestinal anthrax
213
Inhalational anthrax can occur when inhaling as few as _____ anthrax spores—perhaps in a single deep breath.
5000 - 6000 anthrax spores
214
What are the initial symptoms of Inhalational anthrax?
- Initial symptoms resemble common cold or flu
- progresses to Severe breathing problems and shock
215
What type of anthrax - If left untreated, the death rate may exceed 99%
- even when treated aggressively in a state-of-the-art hospital center, once severe symptoms take place, 45-80% of patients could die?
Inhalational anthrax
216
What form of anthrax can be harnessed as a bioweapon?
airborne form
217
How does Anthrax attack the respiratory system?
**1. Sneaking in anthrax spores**
- inhaled into the lungs
**2. Beating the defense **
- WBC attack the spores; futile since only a few are killed
**3. Growing**
- Spores collect in the lymph nodes and develop; vaccinated are able to defeat infection at this point
**4. Striking**
- toxins released spread via the lymphatic system
- poison caused internal bleeding and tissue organ dmg.
- Antibiotics will not save victim once poision hasa circulated
218
What type of anthrax is Characterized by soft tissue infection associated with “skin popping” or other forms of injection drug use and results into the direct injection of the spores to the tissues?
Injectional anthrax
219
What type of anthrax is associated with necrotizing fasciitis, organ failure, shock, coma, and meninigitis?
Injectional anthrax
220
What is the difference between cutaneous anthrax and injectional anthrax?
Difference with cutaneous anthrax: no formation
of black eschar
221
What are the functions of toxins from Anthrax?
- once released it will circulate all throughout the body and the person might die from severe
**1. Protective antigen** - forms channel in membranes allowing 2 factors to enter target cell
**2. Edema factor** - adenylate cyclase which leads to an impairment of host defenses
**3. Lethal factor** - protease causing the lysis of macrophages
222
When anthrax enters the body, where do they usually go?
they usually go to the lymph nodes, aside from the lungs - where they develop and release their toxins
223
What is used to treat all 3 types of anthrax and when can this be given?
Antibiotics
- given prevention after exposure (prophylaxis)
- treatment after infection
224
What is given as a treatment for a person exposed to anthrax but is not yet sick?
PROPHYLAXIS
- penicillin
- levofloxacin,
- Doxycycline,
- Ciprofloxacin,
- combined with Anthrax vaccine to prevent anthrax infection
225
How long does the treatment after infection of anthrax lasts?
Treatment is usually a 60-day course of antibiotics. Success depends on the type of anthrax and how soon treatment begins.
226
# Identify
A severe, often fatal, form of food poisoning characterized by pronounced neurotoxic effects
Botulism
227
What is the causative agent for Botulism?
Clostridium botulinum - Strictly anaerobic gram-positive bacillus
228
What are the unique characteristics of Clostridium botulinum?
- Produces spores which are oval, subterminal, and bulging
- Produces botulinum toxin
229
What is the function of th ebotulinum toxin?
- Blocks the release of acetylcholine (neurotransmitter) from the nerve terminals of neuromuscular junctions
- Leads to descending paralysis ending in death by respiratory paralysis
230
What are the 3 types of botulism?
1. Food-borne botulism
2. Wound botulism
3. Infant botulism
231
What type of botulism is due to ingestion of preformed toxin
▪ Source: preserved, canned food, or vacuum packed food without adequate sterilization?
Food-borne botulism
232
What are the symptoms of Food-borne botulism?
Symptoms: begin 18-36 hours after ingestion of food
▪ Nausea, vomiting, thirst, double vision,
difficulty swallowing, speaking, and breathing
▪ Muscular weakness, blurred vision, and death
233
What are the symtpms of wound botulism?
Symptoms are those of foodborne botulism
except for gastrointestinal components (patient does not experience vomiting)
234
What type of botulims occurs when Spores are ingested in food, get established in the
gut and there produce the toxin? What population does it typically affect?
Infant botulism
- Typically affects infants younger than 1 year
235
In infant botulism, what is the most common food source contaminated with botulinum spores?
Honey (esp. unpasteurized honey)
236
What is the characteristic of an infected infant of botulism?
- Characterized by acute flaccid paralysis in infants
- Baby appears ‘floppy’ (floppy child syndrome)
237
In the laboratory diagnosis of botulism, what specimens can be used as a source of the bacteria?
- Feces,
- food,
- vomitus,
- gastric fluid,
- serum,
- environmental samples and
- occasionally wound exudates
238
In laboratory diagnosis of botulism, what are the culture materials that can be used?
- Specimen inoculated on Egg-yolk Agar (EYA),
- blood agar,
- CMB (Clostridium botulinum isolation) agar
THEY PRODUCE COLONIES RESEMBLING C. botulinum
239
In laboratory diagnosis of botulism, how is the toxin demonstrated?
**Demonstration of toxin: through mouse bioassay**
- mouse is injected with the toxin and dies rapidly,
- so in infants toxin is usually found in stool, however other methods can also be used for the detection of the bacteria:
240
How/where can you detect the toxins of botulinum?
- in infants toxin is usually found in stool, however other methods can also be used for the detection of the bacteria:
- Brain scans
- Spinal fluid examination
- nerve conduction tests
241
All laboratory diagnosis tests for botulism must be done where specifically?
In reference laboratories
242
What is the treatment for Botulism?
1. Elimination of the organism from the GI tract through judicious use of gastric lavage and metronidazole or penicillin therapy.
2. Use of polyvalent antitoxin to neutralize unfixed toxin
3. Adequate ventilatory support
OTHER TREATMENTS
- prophylaxis
- proper canning and preservation of food
- for children younger than 1 yr, they should not eat honey
- prophylactic dose of polyvalent antitoxin is given intramuscularly to all persons who have eaten food suspected of causing botulinum
- active immunization for lab staff who have come in direct contact with patients infected with botulism
243
# Identify
This is An acute contagious disease caused by variola virus, a member of the genus Orthopoxvirus, in the Poxviridae family
Smallpox
244
When was the last known case of smallpox in US? And how was it completely eradicated?
last known case was in US in 1949 - it was completely eradicated because of worldwide vaccination programs
245
When was the first vaccine for smallpox created and when did WHO declare the eradication of the virus?
- first vaccine was created in 1758, but disease continued to kill people
- by 1980, WHO declared that smallpox have been eradicated,
246
Who created the first method for vaccination against smallpox?
EDWARD JENNER: created a method for vaccination against smallpox virus called VARIOLATION
247
What do you all the method of vaccination of Edward Jenner in which people with no smallpox were exposed to materials from a smallpox source or POSTULES by scratching the material on their arm or inhaling through their nose
- after this people develop symptoms such as fever and rash but fewer people died from variolation than if they had acquired smallpox naturally
VARIOLATION
248
Smallpox virus is most stable at what conditions? and they spread most efficiently by? less efficiently by?
- Most stable at low temperatures and low humidity
- Spread most efficiently by means of inhalation and
- less efficiently by means of direct contact with scabs or pustular material from skin lesion
249
What period of smallpox signs and symptoms is indicated?
- Exposure to the virus during which people do not have any symptoms and may feel fine
- 7-17 days
- not contagious
Incubation Period
(virus replicates inside the body)
250
What are the first symptoms of smallpox and in what period does this occur?
First symptoms
- fever
- malaise
- head and body aches
- vomiting
INITIAL SYMPTOMS (PRODOME) period
251
What period in smallpox signs and symptoms is indicated?
- 2-4 days
- Sometimes contagious
- fever is high (101-104 F)
Initial symptoms (Prodrome)
252
What period in smallpox signs and symptoms is indicated?
- Most contagious
- 4 days
- large virus into mouth and throat spread
**Early rash**
- rash emerges first as small red spots on the tongue and in the mouth
253
Laboratory diagnosis of Smallpox can be done through?
1. Direct Detection
2. Electron Microscopy
3. Immunofluorescence
4. PCR
5. Use of Serological tests
254
How is direct detection of smallpox done as a lab diagnosis?
- Culture of veiscular fluid
- Culture pustular fluid
- Culture of the scab
255
How is direct detection done through the use of electron microscopy for the identification of Smallpox?
- Sample: vesicle fluid
- viewed under electron microscope
256
How is immunofluorescence done for lab diagnosis of smallpox?
Sample: skin scraping from infected individual
257
How is PCR used in the lab diagnosis of smallpox?
**virus isolation:** since virus is dormant outside, it needs to be inoculated inside a host cell for replication and development
258
How are srological tests done in the lab diagnosis of smallpox?
**Use of SEROLOGICAL TEST **for the identification of the antigen or the virus or the detection of the anti-variola immunoglobulins or the antibodies that develop 2 weeks after infection;
- so this is used to document if the person is suffering from a recent infection;
- the virus is identified from a panel of monoclonal and polyclonal antibodies for the diagnosis of variola virus
