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MYCV-Complete-Midterm

Medical Laboratory Science (MedTech) (Our Lady of Fatima University)

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MYCOLOGY AND VIROLOGY (LECTURE)

BACHELOR OF SCIENCE IN MEDICAL LABORATORY SCIENCE
OUR LADY OF FATIMA UNIVERSITY - PAMPANGA

MIDTERM
UNIT OUTLINE ● The emergence of a new viral disease
across a very large geographic region
I. Introduction to Virology (worldwide) with prolonged
II. Respiratory Viruses human-to-human transmission is called
III. Gastrointestinal Viruses pandemic.
IV. Hepatitis Viruses ● Genetic shift and the reassortment of genes
V. Herpes Virus combines with those of another organism,
usually an animal.
LESSON I: INTRODUCTION TO VIROLOGY
○ Antigenic Shift
HISTORY ■ Major changes that result in
● Evidence of viral disease exists in ancient novel viral antigens
records, dating back to as far as 23 BC, ○ Antigenic Drift
when the Eshnunna Code of ancient ■ Minor changes that occur
Mesopotamia noted “the bite of mad dogs infrequently
to a ect disease on humans”. ● Protection from viral infection has been
● Homer, author of the Iliad, characterizes successful for some viral pathogens.
Hector as “rabid”. ● Vaccination (immunization) has proven to
● Aristotle’s work, The natural History of be a valuable tool in the control of viral
Man, written in the fourth century BC, diseases such as yellow fever and rabies
describes a “madness” in dogs that and has been instrumental in the
“causes them to become very irritable eradication of one of the most lethal
and all mammals they bite become viruses, smallpox. However, many viral
diseased.” diseases such as influenza, acquired
● What remains apparent in all these early immunodeficiency syndrome (AIDS), and
writings is that all writers realized the hepatitis continue to pose challenges in
communicable nature of something unseen. treatment, prevention, and control.
VIRUSES VIRAL STRUCTURE
● A submicroscopic, obligate intracellular Virus particles, referred to as virions, consist of two
parasite, among the smallest of all or three parts:
infectious agents, and capable of infecting ● An inner nucleic acid core, consisting of
any animal, plant, and bacterial cell either ribonucleic acid (RNA) or
● Viruses are found in every ecosystem. deoxyribonucleic acid (DNA).
Incapable of replication without a living ● A protein coat that surrounds and protects
host, animal, plant, or bacterial cell the nucleic acid (the capsid).
● Virus types are very specific, and each has ● In some of the larger viruses, a
a limited number of hosts it can infect; this lipid-containing envelope that surrounds
is referred to as viral tropism. the virus.
● Transmission of viruses from animals to ● Nucleocapsid is often used to describe the
humans still occurs, as demonstrated in the nucleic acid genome surrounded by a
more recent viral outbreak associated with symmetric protein coat.
the severe acute respiratory syndrome
(SARS), West Nile, and influenza A H5
viruses, as well as the 2009 H1N1 virus,
formerly known as the pandemic “Swine
Flu”. The influenza virus has proven to be
one of the deadliest viruses to a ect
humans; its history dates back to the 1700s
in Italy. The virus was named to indicate
disease resulting from the “influence” of
miasma (bad air).

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● Nucleic acid genome encodes the proteins Pox virus

required for viral penetration, transmission, 1. Largest virus
and replication. 2. 260x450nm in diameter
● Viral genome structure determine the
mechanism for viral replication Polio virus
○ A variety of viral genome structure ● Smallest virus
exist, including
● 25nm in diameter
1. Sense–strand RNA
2. DNA genomes ● Some enveloped viruses also contain a
● Viral capsid protects the viral genome and is matrix protein that lies between the
responsible for the tropism to specific cell envelope and the nucleocapsid. The matrix
types in naked viruses proteins have enzymatic activities or
○ Composed of repeating structural biologic functions related to infection, such
subunits referred as capsomeres as inhibition of host-cell transcription.
● Glycoprotein spikes
VIRAL TAXONOMY
○ Assist in stabilization of attachment
for the lipid envelope and for ● Viral morphology
attachment to the host cell to Three viral morphology
facilitate viral entry 1. Helical
VIRAL STRUCTURE: 2 TYPES 2. Icosahedral
3. Complex
● Method of replication, including genome
organization (whether the genome is RNA
or DNA and single- or double-stranded)
● Presence or absence of a lipid envelope
VIRAL REPLICATION
● The phrase “means of replication” refers to
the strategy the virus uses to duplicate the
viral genome
● Viruses are strict obligate intracellular
parasites that rely upon components of the
host cell to replicate and therefore are
capable of replication only within a host cell
NAKED ● The six steps of virus replication, called the
infectious cycle, proceed as follows.
● Very resistant to environmental factors
1. Attachment
because of their stability
2. Penetration
● They typically are transmitted by the
3. Uncoating
fecal-oral route
4. Macromolecular synthesis
ENVELOPE 5. Viral assembly
● Very susceptible to drying and destruction 6. Release
in the environment 1. ATTACHMENT
● This prevents exposure to the environment
● Also referred to as adsorption, is the first
and successful propagation of the viral
step of the infectious cycle
agent to another susceptible host
● It involves the recognition of a suitable
● They typically are transmitted by direct
host cell and specific binding between viral
contact, such as respiratory, sexual, or
capsid proteins (often the glycoprotein
parenteral contact
spikes) and the carbohydrate receptor of
Envelope viruses are typically more susceptible the host cell
to inactivation by:
1. High temperature 2. PENETRATION
2. Extreme pH ● Is the process by which viruses enter the
3. Chemicals host cell. One mechanism of penetration
involves fusion of the viral envelope with
the host cell membrane.

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● Detection of syncytia can be used to 6. RELEASE

determine the presence of virus in cell ● Release of intact virus particles occurs
cultures or stained smears of clinical after cell lysis (lytic virus) or by virus
specimens particle budding from cytoplasm
Syncytia membranes
● A method, not only provides mechanism for
internalizing the virus, but also leads to the
fusion of infected host cell to nearby host
cell
,

● Other mechanisms of viral penetration

include phagocytosis by host cells
(endocytosis) or injection of viral nucleic
acids into the host cell.
3. UNCOATING
● Occurs once the virus has been internalized
● It is the process by which the capsid is
removed
● Uncoating is necessary to release the viral
genome for delivery of the viral DNA or
GOOD TO KNOW EXAMPLE
RNA to its intracellular site of replication in
the nucleus or cytoplasm ● Enteroviruses have single-stranded RNA
genomes that synthesize additional strands
4. MACROMOLECULAR SYNTHESIS of RNA, whereas retroviruses make RNA
● Involves the production of nucleic acids molecules in a two-step process by first
and protein polymers synthesizing DNA, which subsequently is
● Viral transcription leads the synthesis of converted to RNA.
messenger Rna (mRNA), which encodes EPIDEMIOLOGY
early and late viral proteins
● Viruses are transmitted from person to
● Early proteins are nonstructural elements,
person by the respiratory, fecal-oral, and
such as enzymes, and late proteins are
sexual contact routes; by trauma or
structural components.
injection with contaminated objects or
● The mechanics of macromolecular synthesis
needles; by tissue transplants (including
varies depending on the organization of the
blood transfusion); by arthropod or animal
viral genome
bites; and during gestation (transplacental
transmission

5. VIRAL ASSEMBLY
● Is the process by which structural proteins,
genomes, and in some cases viral enzymes
are assembled into virus particles (virion)
● Envelopes are acquired during viral
“budding” from a host cell membrane
BUDDING
● Additional step if the virus has ENVELOPE
Acquisition of an envelope is the final step of viral
assembly, considering if infected by enveloped
virus

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Electron Microscope (or some Brightfield)

● Detect viruses

DNA viruses (Family)

● PolPaPaAdPoHeHe

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LESSON II: RESPIRATORY VIRUSES

FAMILY GENOME GENERA SPECIES
● Enterovirus (often associated) ● Coxsackievirus
● Parechovirus ● Echvorius, Polio virus
PICORNAVIRIDAE SSRNA
● Hepatovirus ● Hepatitis A virus
● Rhinovirus
● Coronavirus ● Mers-Cov, Sars-Cov
CORONAVIRIDAE SSRNA ● Sars-Cov-2
○ (aka Covid-19)
ORTHOMYXOVIRIDAE SSRNA ● Influenza virus ● Influenza virus A to C
● Rubulavirus ● Mumps virus
● Morbillivirus ● Measles virus
● Pneumovirus ● Parainfluenza virus
PARAMYXOVIRIDAE SSRNA ● Metapneumovirus ● Respiratory Syncytial
virus
● Human
Metapneumovirus

○ Identified individually by a serum

PICORNAVIRIDAE
neutralization test
● One of the largest families
● Naked ssRNA virion ranging from 20-30 ● Enterovirus 70
nm in size ○ Cause acute hemorrhagic
conjunctivitis
● One of the smallest virus to exist, but ○ Involvement of respiratory
belongs to one of the largest families secretions
because it has more than 280 members ● Enterovirus 72
● Mode of Transmission ○ Hepatitis A with short incubation
○ Spread via aerosol inhalation,
COXSACKIEVIRUS A
○ Fecal-oral route (polio virus), and
○ Fomites ● Genera: enterovirus A
● Treatment ● Causes hand, foot, mouth disease, also
○ Only available for Polio in the form conjunctivitis (types A5, A10, A16)
of vaccination. COXSACKIEVIRUS B
○ Salk vaccine
■ Made up of formalin- ● Aka Enterovirus B
inactivated vaccine ● Causes myocarditis and meningitis
○ Sabin vaccine POLIOVIRUS
■ Made up of attenuated
● Aka Enterovirus C
vaccine (commonly used)
● Infects GI tracts and spreads to CNS
Attenuated vaccine causing meningitis or paralysis
● Weakened version of the virus
RHINOVIRUS
● The virus is alive, but weakened just enough
to activate the immune system ● Genera: rhinovirus
● Does not cause harm or disease ● Associated with common colds
● Has 150 serotypes
CLINICAL SIGNIFICANCE Possible part of the body that is infected by
ENTEROVIRUSES Rhinovirus
● Known for causing acute non-specific Nasal epithelial cells
febrile syndrome ● Inactivate the mediators of inflammation
● Nonrespiratory caused, but somehow threat Most people experience 2-5 colds per/each year
● Almost 50% is caused by Rhinoviruses
● Enteroviruses have also been implicated in
● Because Rhinoviruses has 150 serotypes
early onset diabetes, cardiomyopathy, and
● Transmission is primarily via aerosols, but
fetal malformation
contact with secretions and fomites can
● Enteroviruses have no group antigen
also cause infection

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CATEGORY OF VARIANCES
LABORATORY DIAGNOSIS
VARIANT OF CONCERN
SAMPLE
● Potential to cause enhances
● Swab must be from mouth and/or bullae
transmissibility, reduction in
located on the soles of feet or palms of
neutralization by antibodies through
hands (suggested for Coxsackievirus A)
passive or acquired immunity.
Since Coxsackievirus A causes hand, foot, and VARIANT OF INTEREST
mouth disease
● Shows specific genetic markers associated
CULTURE METHODS with changes to receptor binding, reduced
● PMK (Primary Monkey Kidney cells) neutralization of antibodies, reduced
● CPE treatment e cacy.
● Human fetal diploid fibroblast lines
SARS-CoV-2 VARIANTS
MOLECULAR METHODS
● Alpha (B.1.17) → UK (Dec. 2020)
● Nucleic amplification test of clinical ● Beta (B.1.351) → South Africa (Dec. 2020)
specimen ● Gamma (P.1) → Brazil (Jan. 2021)
● Acid test ● Delta (B.1.617.2) → India (Dec. 2020)
○ Presumptive identification for ● Omicron (B.1.1.529) → South Africa (Nov.
Enterovirus and Rhinovirus 2021)
○ Resistant = Enterovirus
○ Susceptible = Rhinovirus LABORATORY DIAGNOSIS
ELECTRON MICROSCOPY
CORONAVIRIDAE
● Enveloped ssRNA virion ranging from 25-32 SEROLOGY
kb in size ● Antigen kits
Coronaviridae → family ○ Rapid antigen tests (RAT)
● Morphology ○ Used for screening
○ Enveloped helical ○ If positive, subject for PCR testing
● 2 subfamilies ○ If negative, no need for PCR
○ Coronavirinae ■ In some cases even if
○ Torovirinae negative, if the patient is
symptomatic, PCR is still
● Mode of Transmission
needed.
○ Spread via person to person direct
contact, MOLECULAR
○ Mucus droplet, ● ELISA
○ Airborne routes (for enclosed) ● RT-PCR
● Preventive measure through vaccination is ● Western blot
available for SARS-Cov-2, social distancing
and quarantine period during incubation ORTHOMYXOVIRIDAE
period of 7-14 days.
● Enveloped ssRNA virion, known for their
CLINICAL SIGNIFICANCE matrix protein and nucleoprotein
SARS-CoV ● AKA Influenza Viruses
● Subtype classification of influenza virus is
● Hong Kong in late 2002 causing respiratory
based on surface glycoprotein (separate H
distress.
and N ag)
MERS-CoV ○ H antigen (hemagglutinin)
● Middle east in August 2013, Saudi Arabia ■ Used to bind host cells →
in 2014 causing respiratory distress. ● H1 to H16
○ N antigen (neuraminidase)
SARS-CoV-2 ■ Cleaves budding viruses from
● Wuhan, China in late 2019 causing infection cells → N1 to N9
respiratory distress. ● Mode of Transmission
○ Spread through aerosol inhalation

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with incubation period of 1 to 4 ○ Known for HN and F (fusion) antigen

days ■ Bind H and N ag
● Treatment HN and F
○ Amantadine ● Hemagglutinin neuraminidase
○ Rimantadine ● Surface antigens of Parainfluenza viruses
○ Zanamivir
○ Oseltamivir ● Mumps virus from Rubulavirus
■ Amantadine and ○ Known for its Hn and F antigens
Rimantadine developed ● Measles virus from Morbillivirus and a
resistance highly contagious agent
● Mode of Transmission
CLINICAL SIGNIFICANCE ○ Respiratory secretions
● Influenza is characterized by rapid onset of ○ Saliva droplets
malaise (pang-hihina), high fever, myalgia ○ Aerosol inhalation
(pan-lalambot), fatal viral pneumonia CLINICAL SIGNIFICANCE
● Influenza A and B
● Influenza A virus major antigenic shifts PARAINFLUENZA VIRUS
○ Influenza A virus H1N1 (Spanish flu ● Primary cause of respiratory disease in
in 1918) young children.
○ Influenza A virus H2N2 (Asian flu in ○ Croup
1957) ■ High fever, hoarse cough
○ Influenza A virus H3N2 (Hong Kong MUMPS VIRUS
flu in 1968)
○ Influenza A virus H5N1 (Avian flu in ● Acute illness producing unilateral or
1998) bilateral swelling of parotid glands (beke)
● Influenza B Vaccine available for Mumps
○ Only causes minor infection ● A vaccine e ective in controlling the
disease is available in 2 doses
LABORATORY DIAGNOSIS ● First dose: 12-15 months
SPECIMEN ● Second dose: 4, 6, 11, or 13 years old
● Nasopharyngeal swabs/washes/aspirates MEASLES VIRUS (Rubeola)
SEROLOGICAL METHOD ● Known for koplik spots in buccal mucosa
● DFA Measles
● EIA ● Highly contagious
● Optical immunoassays ● Spreads by aerosol
CULTURE METHOD ● Initial replication takes place in the
mucosal cells of the respiratory tract
● Amniotic cavity of embryonated eggs ● Measles virus then replicate in the local
● PMK lymph node and spreads systemically
● MDCK
● The best specimens are still the KOPLIK SPOTS
Nasopharyngeal swabs that should be ● Irregular red spots with a bluish-white
collected early in the course of the speck in the center, generally appeared
disease 2-3 days before the rash
● Specimen should never be frozen ● Used for diagnosis of measles virus
● Can use rapid antigen test
○ 20-30 mins before result
● Culture media are living cells since viruses
can only be replicated on living host cell

PARAMYXOVIRIDAE
● Size
○ 150-300 nm
● Enveloped ssRNA virion
● Parainfluenza virus

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RESPIRATORY SYNCYTIAL VIRUS

● Causes
○ Bronchiolitis
○ Pneumonia
○ Croup among infants

LABORATORY DIAGNOSIS
SAMPLE
● Aspirated secretions and nasopharyngeal
washes for PIV
● Also we can use urine and CSF for mumps
● Nasopharyngeal swab and urine for
measles
Measles is easily diagnosed clinically
● Few request for laboratory identification
are made
● Especially if Koplik spots are visible
SEROLOGICAL METHOD
● Serum neutralization
● DFA
● EIA
● IF tests
CULTURAL METHOD
● PMK cells with distinctive spindle shaped
or multinucleated cells for measles and
Hep2 cells for RSV forming syncytia (pseudo
multinucleated)

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LESSON III: GASTROINTESTINAL VIRUSES resulting in considerable morbidity and

mortality
● Adenoviridae
● Adenovirus produces a characteristic
● Caliciviridae
grapelike cluster cytopathic e ect (CPE).
● Reoviridae
● Astroviridae Adenovirus was first isolated from adenoid tissue
● The Picornaviridae family ● Hence, named Adenoviridae or Adenovirus
○ Piccolo: italian word: small naked, ● Adenoviruses are quite stable and can be
ssRNA isolated in human embryonic kidneys and
○ Enterovirus (enteroviruses) many continuous epithelial cell lines.
○ Rhinovirus (rhinoviruses) “Isolated in human embryonic kidney”
○ Hepatovirus (hepatitis A virus) ● Because other viruses need primary
○ Parechovirus (parechoviruses) monkey kidney cells for them to be isolated
○ Aphthovirus (foot-and-mouth ● These adenoviruses can be identified but
disease viruses) not serotyped using EIA
○ Cardiovirus (cardioviruses)
● The first four groups contain important ● Serotyping is accomplished by serum
human pathogens neutralization or hemagglutination
● Poliovirus, Coxsackie, Echovirus, Enterovirus inhibition.
○ Fecal to oral CALICIVIRIDAE
ADENOVIRUSES Family Caliciviridae
Family Adenoviridae Common name Calicivirus
Common name Adenovirus Virus Noroviruses
Virus Adenovirus Nonenveloped, icosahedral capsid
Characteristics surrounding single-stranded
Double-stranded deoxyribonucleic
ribonucleic acid (ssRNA) genome
acid (dsDNA) genome; icosahedral
Characteristics Transmission Fecal-oral
capsid, naked/no envelope;
approximately 50 human serotypes Disease Nausea, vomiting, and diarrhea
Respiratory, fecal-oral, and direct Electron microscopy (EM), Reverse
Transmission transcriptase polymerase chain
contact (eye) Diagnosis
Site of latency Replication in oropharynx reaction (RT-PCR), Enzyme
immunoassay (EIA) for noroviruses
Pharyngitis, pharyngoconjunctival
fever, keratoconjunctivitis, Treatment Supportive
Disease pneumonia, hemorrhagic cystitis, Prevention Avoid contact with virus
disseminated disease, and
gastroenteritis in children 5 genera under Caliciviridae
Cell culture (HEp-2 and other Norovirus, Sapovirus, Norovirus, Lagovirus,
continuous human epithelial lines), Vesivirus
Diagnosis
enzyme immunoassay (EIA) for ● Members of the Norovirus and Sapovirus
gastroenteritis serotypes 40-41 genera are the primary cause of viral
Treatment Supportive gastroenteritis in humans
Vaccine (adenovirus serotypes 4 and ● Referred to as the human caliciviruses
Prevention
7) for military recruits (HuCV). Previously called “Norwalk-like
viruses” and “Sapporo-like viruses,” the
ADENOVIRIDAE viruses were named after their prototype
● Respiratory and gastrointestinal diseases strains
are the most common clinical ● Noroviruses are easily transmitted in
manifestations associated with adenovirus water, person to person, or in airborne
infection. droplets of vomitus. The virus persists in
● Adenovirus serotypes 40 and 41 cause water despite treatment processes.
gastroenteritis in infants and young Most common transmission → food-borne
children, and other serotypes are associated
● The incubation period is 24 to 48 hours;
with conjunctivitis and keratitis.
the onset of severe nausea, vomiting,
● A unique feature of the adenoviruses is the
diarrhea, and low-grade fever is abrupt.
ability to cause severe, acute respiratory
disease epidemics in military recruits, often

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● Electron microscopy, immune electron ● Gastroenteritis caused by rotavirus can

microscopy, and real time PCR. occur in children of all ages but is most
These are the used diagnosis because viruses common in infants from 6 months to 3
cannot be grown in culture years old
● Rotavirus occurs more frequently in the
REOVIRIDAE winter months in temperate climates.
Family Reoviridae ● Enzyme-linked immunosorbent assay
Common name Reovirus (ELISA) and latex agglutination tests
detect the viral antigens in fecal material.
Virus Rotavirus
Segmented, double-stranded, ORBIVIRUSES & COLTIVIRUSES
Characteristics ribonucleic acid (dsRNA) genome;
Non Gastroenteritis
icosahedral capsid with no envelope
● common in animals
Fecal-oral; survives well on
Transmission ● vector-borne
inanimate objects
Gastroenteritis in infants and children ● Orbiviruses are a genus within the reovirus
Disease family.
6 months to 2 years
Enzyme immunoassay (EIA), latex ● They commonly infect insects, and many are
Detection transmit-ted by insects to vertebrates.
agglutination (LA)
Winter-spring seasonality in ● None of these viruses cause serious clinical
Epidemiology temperate climates; nosocomial disease in humans, but they may cause mild
transmission can occur easily fevers.
Supportive, especially fluid ● Serious animal pathogens include
Treatment bluetongue virus of sheep and African horse
replacement
Prevention Avoid contact with virus; vaccination sickness virus.
● Coltiviruses form another species within the
● Incubation period: 1-4 days Reoviridae.
● Rotaviruses replicate in the epithelial cells in ● Colorado tick fever virus, transmitted by
the tips of microvilli of the small intestine ticks, is able to infect humans.
● The reoviruses were first isolated from ASTROVIRIDAE
respiratory and enteric specimens and
● Exhibit a distinctive star-like morphology
therefore are referred to as
in the electron microscope
respiratory-enteric-orphan viruses
● Astroviruses cause diarrheal illness and
(reoviruses)
may be shed in extraordinarily large
The term orphan was originally included in the quantities in feces.
description of the virus as a result of absence of ● Transmitted by the fecal-oral route
the associated disease when the viruses were first ● Pediatric gastroenteritis or asymptomatic in
described → orphan viruses all ages; watery diarrhea
● Rotaviruses are naked/nonenveloped, ● Detection can be achieved with electron
double-stranded RNA viruses composed of microscopy, antigen, or RT-PCR methods.
three concentric protein shells, the outer Contain single-stranded positive sense RNA
shell, the inner shell, and the core ● 6.4 - 7.4 kb in size
● Rotavirus is now recognized as the major
causative agent of infantile severe
gastroenteritis throughout the world.
Virus Relative Medical Importance Epidemiology Diagnostic Tests
Major cause of diarrhea in EIA, LA
Rotavirus ++++
infants
Diarrhea in infants and EIA, EM (especially types
Enteric adenoviruses ++
young children 40-41)
Epidemics in children and EM, RT-PCR
Noroviruses (caliciviruses) +++
adults
Astroviruses + Diarrhea in children EM

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PICORNAVIRIDAE
Family Picornaviridae
Common name Picornaviruses
Single-stranded ribonucleic acid
Characteristics (RNA) genome; icosahedral capsid
with no envelope
● Enteroviruses
● Poliovirus (3 types)
● Coxsackie virus, group A (23
types)
Virus
● Coxsackie virus, group B (6
types)
● Echovirus (31 types)
● Enteroviruses (5 types)
Transmission Fecal-oral
Predominant virus in parentheses:
polio (poliovirus); herpangina
(coxsackie A); pleurodynia (coxsackie
B); aseptic meningitis (many
enterovirus types); hand-foot-mouth
disease (coxsackie A); pericarditis and
Disease
myocarditis (coxsackie B); acute
hemorrhagic conjunctivitis
(enterovirus 70); and fever, myalgia,
summer”flu” (many enterovirus
types), neonatal disease (echoviruses
and coxsackie viruses)
Cell culture (PMK and HDF), PCR, and
Detection
serology
Treatment Supportive, pleconaril in development

Hepatitis A virus (enterovirus type

Virus
72)
Transmission Fecal-oral
Hepatitis with short incubation,
Disease abrupt onset, and low mortality; no
carrier state
Detection Serology
Treatment Supportive
Vaccine; prevent clinical illness with
Prevention
serum immunoglobulin

Virus Rhinovirus (common cold virus)

Characteristics Approximately 100 serotypes
Transmission Contact with respiratory secretions
Disease Common cold
Cell culture (usually not clinically
Detection
necessary), RT-PCR
Treatment Supportive
Prevention Avoid contact with virus

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LESSON IV: HEPATITIS VIRUSES

FAMILY GENOME GENERA SPECIES
PICORNAVIRIDAE SSRNA ● Hepatovirus Hepatitis A virus
HEPADNAVIRIDAE dsDNA ● Orthohepadna virus Hepatitis B virus
FLAVIVIRIDAE SSRNA ● Hepacivirus Hepatitis C virus
UNCLASSIFIED SSRNA ● Deltavirus Hepatitis D virus
HERPEVIRIDAE SSRNA ● Herpevirus Hepatitis E virus

HEPATITIS A ● Serological method: Detection of IgM to

HAV
● Hepatitis: hepatic infection, liver infection
● Small, naked, icosahedral ssRNA virus In the laboratory with no molecular machine, kits
● MOT: Fecal oral route, close personal are used.
contact, ingestion of contaminated food ● Detection of IgM to HAV is the best method
● Incubation period: Sheds in feces during for the laboratory diagnosis of Hepa A virus
the incubation period of 30 days Simple kit:
● Add sample, drop reagents, then look for
● Low mortality rate and no persistence
two lines
● Does not cause chronic liver damage
● When kit is used in serology, manner of
CLINICAL SIGNIFICANCE reporting is Reactive only
● Adults can experience mild to severe ○ Not assuming if it is positive since
hepatitis with abrupt onset experiencing the kits for serology are screening
fever, chills, fatigue, malaise, aches, pains, tests only, need further confirmatory
and jaundice. ● Molecular method: Antibody detection with
RT-PCR
Serological → screening
Molecular → confirmatory (antibody detection with
RT-PCR)

LABORATORY DIAGNOSIS
HEPATITIS B
● Specimen: Blood and stool sample
Most important hepatitis virus
Why blood sample, if route is fecal-oral:
● Enveloped, partially dsDNA virus
● When Hepa A enters the body, it will go
containing several antigens
straight to liver, specifically hepatocytes
● Since viruses need cells to replicate, and Why partially dsDNA virus:
since hepatitis viruses mainly infect the ● Hepa B virus is consist of incomplete
liver, hepatocytes or liver cells are infected. positive strand and complete negative
○ Viremia: viruses in the blood → strand in DNA
hepatocytes for replication ○ The positive strand has gaps and it
Stool sample is not fully copy of negative strand,
● Hepa A sheds (viral shedding) in the that’s why it is called partially
intestine, then the virus goes out in feces dsDNA
<

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● Several antigens:
● HBs Ag (Surface antigen) = Anti-HBs
● HBe Ag (Envelope antigen) = Anti-HBe
● HBc Ag (Core antigen) = Anti-HBc

LABORATORY DIAGNOSIS
● MOT: Sexual, perinatal, and parenteral ● Specimen: Blood sample (serum)
routes
Hepatitis B is also known as Serum Hepatitis
Perinatal
Serological methods: Markers
● Transfer of virus from mother to newborn
● HBsAg: indicates active infection, long term
Parenteral
carrier, incubation period (2 to 6 months)
● Needle prick
HbsAg: test kit, serum → reagents → two lines
● Incubation period: Ranges from 2 to 6
(reactive to virus)
months
● Anti-HBs: indicates convalescence or
CLINICAL SIGNIFICANCE immune status
● Primarily a bloodborne pathogen Test to know titer to Hepa B
Infected patients with Hepa B can have as many as ● Reference value depends on the machine
1 million infectious particles per mL of blood ● IgM anti-HBc: indicates early in the course
● 1 mL of blood = 1 million Hepa B of disease or acute infection
● Lower concentration in semen and vaginal ● IgG anti-HBc: indicates that the infection
secretions has been resolved
● Insidious onset that includes fever, ● HBeAg: indicates chronic infection and
anorexia, hepatic tenderness, and jaundice high infectivity
● Individual with chronic infection have
higher risk of liver disease
● Risk liver disease: cirrhosis, carcinoma

Hepa B AKA Serum Hepatitis

● Complete Hepatitis B virus that causes infection → Dane particle
● Hepatitis B core antigen → not a serological marker/not detected on serum, covered by envelope
○ Detected through biopsy of infected liver

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HEPATITIS C VIRUS CLINICAL SIGNIFICANCE

● Small, enveloped ssRNA virus ● Co-infection: patient is simultaneously
● MOT: Sexual, perinatal, & parenteral routes infected with HBV and HDV
● Incubation period: Ranges from 2 weeks ● Superinfection: patient has HDV due to
to 6 months chronic HBV infection
Hepatitis C → previously classified as Non-A and Co-infection → simultaneously
Non-B hepatitis Superinfection → sequentially
● Major cause of post-transfusion hepatitis
● Hepa C is mainly transmitted through Hepa D virus needs presence of Hepa B virus
exposure on contaminated blood ● It is a parenterally transmitted infection but
● Usually asymptomatic can only occur in the presence of Hepatitis
B
● Is is an incomplete virus
LABORATORY DIAGNOSIS
● Specimen: Blood sample
● Serological method: Antibody detection,
Agglutination testing
● Molecular method: RT-PCR assay

HEPATITIS E VIRUS
● Small, naked, ssRNA virus
● MOT: Fecal oral route, ingestion of
contaminated drinking water
● Incubation period: Ranges 2 to 9 weeks
Same MOT as Hepa A, but Hepa E is also called
water-borne hepatitis due to ingestion of
contaminated drinking water
CLINICAL SIGNIFICANCE
CLINICAL SIGNIFICANCE ● Acute, self-limiting disease with clinical
● Known for its non-A and non-B hepatitis symptoms similar with HAV
(NANB) ● Symptoms include fever, malaise, nausea.
● Some HCV-positive patient can become Vomiting, jaundice and dark colored urine
long-term carriers and some with chronic Since HEV is a self limiting hepatitis, it has no
infection develops cirrhosis as a major risk progression to become chronic.
factor for hepatocellular carcinoma ● Also associated with high rate of mortality
LABORATORY DIAGNOSIS in pregnant women
● Specimen: Blood sample LABORATORY DIAGNOSIS
● Serological method: Enzyme immunoassay,
● Specimen: Blood and stool sample
Immunoblot assay
● Serological method: ELISA for antibody
● Molecular method: Nucleic acid
detection
amplification testing

HEPATITIS D VIRUS
● UNCLASSIFIED
● Small, spherical ssRNA virus
● MOT: Parenteral routes, mucosal contact
among epidemic areas
● Incubation period: Ranges 2 to 8 weeks
○ (Superinfection) or 45 to 160 days
(Co-infection)

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LESSON V: HERPES VIRUS

FAMILY GENOME GENERA SPECIES
HSV-1, HSV 2/ HHV-1,
HERPESVIRIDAE dsDNA ● Simplexvirus
HHV-2
HERPESVIRIDAE dsDNA ● Varicellovirus VZV/HHV-3
HERPESVIRIDAE dsDNA ● Lymphocryptovirus EBV/HHV-4
HERPESVIRIDAE dsDNA ● Cytomegalovirus CMV/HHV-5
HERPESVIRIDAE dsDNA ● Roseolovirus HHV-6
HERPESVIRIDAE dsDNA ● Rhadinovirus KS/HHV-8

● All are dsDNA, icosahedral, and have ORAL HERPES:

amorphous integument surrounding capsid ● Caused by HSV-1 and HSV-2
and outer envelope ● Incubation period: 2 days to 2 weeks
● All herpes virus have corrosive malignancy ● Primary infection
and a lifelong persistence in their hosts ○ Shows on mucosal vesicle inside
● Herpes virus is latent between the active the mouth or as ulcerations that
infection may be widespread and involve the
○ Can be reactivated when exposed to buccal mucosa, posterior pharynx,
stimuli (stress, increase ca eine, gingival and palatal mucosae
sunlight exposure) (similar with acute pharyngitis)
■ Sunscreen is not e ective if ● Recurrent infection
you have herpes virus ○ Shows on the on the border of lips
○ Reactivation of herpes virus can at the junction of oral mucosa and
cause reappearance of lesions skin, with an early symptom of
● Herpes-7 is same as Herpes-6 burning or pain followed by
vesicles, ulcers and crusted lesions
HERPESVIRIDAE
PRIMARY INFECTION RECURRENT INFECTION
● Icosahedral capsid, enveloped, linear
dsDNA
● Herpesviruses can infect only primates
except for herpes B virus
Infection to human came from animal
handlers/researchers
CLINICAL SIGNIFICANCE
Before, oral herpes infection was usually caused by
● Lesions that occur on mucous membranes HSV-1 only. Due to surveys and statistics of WHO
are evidence of viral infection. and CDC, it was found out there are also oral
Laboratory (test) is not useful for herpes viruses herpes cases caused by HSV-2.
● Doctors depend on patient’s symptoms
GENITAL HERPES:
○ Ex. chicken pox is evident, no need
for lab tests ● Caused by HSV-1 and HSV-2
● Categories: primary and recurrent infection ● Incubation period: ranges from 2 to 11
○ Primary infection: First encounter days
in an infection Usually, the genital herpes infection are most
○ Recurrent infection: Latency, can commonly caused by HSV-2
lead to prolonged/lifetime infection ● Urethra is the commonly involved for
primary infection of both men and women
HERPES SIMPLEX VIRUSES / ● Primary infection
HUMAN HERPES VIRUS ○ Female: shows vesicles on the
● MOT: Spread by contact with mucosa of labia, vagina, or both,
contaminated secretions and urethra.
○ Male: shows vesicles on the shaft,

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glans, and prepuce of the penis, and layer, not deeply in the tissues, hence can
urethra. be treated easily if managed earlier.
● Recurrent infection ● Primary infection
○ Involves the primary infections but ○ Swelling of the eyelids associated
urethra is less commonly involved. with vesicles
○ Symptoms are less severe, but this ○ Destructive ulceration and
infection doubles the risk of HIV. perforation of the cornea
FEMALE GENITAL HERPES MALE GENITAL HERPES

LABORATORY DIAGNOSIS
NEONATAL HERPES: ● Specimen: Aspirates from vesicles, open
lesions, host cells from infected sites
● Caused by HSV-1 and HSV-2
○ Culture method: CPE (growth within 24
● HSV-2 is more severe than HSV-1
hours, replication)
● Most newborns (<1 month old) are infected
by mothers who are asymptomatic Culture method is best and usually preferred.
shedding the virus during primary infection ● Sample should be aspirates from vesicles or
passing in through the neonate open lesions to confirm diagnosis especially
if possible for HSV encephalitis; also
The risk of transmission is very low when the
possible for brain biopsy
mother has recurrent herpes, only increases if the
● Usually tissue culture medium → for viruses
mother has primary infection.
● Serologic method: Antigen detection panel,
● Cesarean delivery significantly reduces the
presence of monoclonal antibodies
risk of transmission
● Molecular method: Gene amplification
Interventions technique
● Cesarean delivery
● After CS, application of suppressive Cells of sample can be used for molecular method
antiviral tenity (?) at delivery decreases risk ● Especially for encephalitis
of transmission
VARICELLA-ZOSTER VIRUS
HSV ENCEPHALITIS:
● MOT: Droplet inhalation or direct contact
● Caused by hsv-1 and hsv-2 with infectious lesions
● hsv-1 (older children), hsv-2 (neonates) ● Incubation Period: 14 to 16 days (CDC)
● Associated with immunocompromised
2 di erent clinical manifestations
status, causes fatal sporadic encephalitis
1. Varicella → chicken pox
● HSV encephalitis is rare but fatal 2. Zoster → shingles
● CDC
○ 17% of patients with HSV CLINICAL SIGNIFICANCE
encephalitis dies, since brain is ● Varicella is the primary infection and
involved highly contagious that includes febrile
○ Antiviral treatment increases illness, rash, and vesicular lesions that
survival rate appears first on the head and trunk then
spreads to the limbs.
OCULAR HERPES:
● Herpes Zoster in the reactivation as the
● Caused by HSV-1 and HSV-2 virion remains latent in the dorsal root or
● Most common cause of corneal infection at the cranial nerve ganglia after primary
Corneal involvement can result to destructive infection. Known for rash, vesicular lesions
ulceration and perforation of cornea that can lead in unilateral dermatome pattern, prolonged
to blindness disabling pain that remains for months
● Usually infects the superficial epithelial

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Kapag nagkabulutong, possible na magkabulutong hepatosplenomegaly, microcephaly,

ulit but instead of chicken pox, tawag na ay chorioretinitis, and may lead to mental
shingles. retardation, deafness and intellectual
impairment
LABORATORY DIAGNOSIS
● Specimen: Sterile body fluid (bu y coat),
urine, respiratory secretions
Urine sample is the most common specimen for
Cytomegalovirus
● Serology is not useful for CMV
● Culture method: CPE (growth for 3 weeks),
LABORATORY DIAGNOSIS human diploid fibroblast cell lines
● Specimen: Blood, fresh lesion sample ● Molecular method: PCR method
● Culture method: CPE shows changes within
3-7 days, grows on Vero cells EPSTEIN-BARR VIRUS
Cytopathic e ect (CPE) Causes infectious mononucleosis
● Wait for 3-7 days then look for the changes ● AKA Kissing disease
in negative control in tissue culture ● MOT: Sexual contact, direct contact with
● Serological method: Fluorescent-labeled infected body fluid
monoclonal antibodies (confirmatory test) ● Incubation period: Ranges from 2 weeks
● Molecular method: PCR assay to 2 months
CLINICAL SIGNIFICANCE
CYTOMEGALOVIRUS
● Known for causing Infectious
● MOT: Sheds in blood, saliva, tears, urine,
Mononucleosis and associated with
stool, breast milk, and can be transmitted
Burkitt’s lymphoma, Hodgkin diseases,
sexually
and Nasopharyngeal carcinoma
● Transmitted sexually via semen, cervical
Severity of Epstein-barr virus can lead to
and vaginal secretions through the blood
thrombocytopenia, hemolytic anemia, Reye’s
and blood products
syndrome, encephalitis, and other neurologic
syndrome.
● Signs and symptoms
○ Sore throat
○ Fever
○ Lymphadenopathy
○ Hepatomegaly
○ Splenomegaly
○ General malaise that resolves in few
weeks
CLINICAL SIGNIFICANCE LABORATORY DIAGNOSIS
● Most common congenital infection, known ● Specimen: Blood sample
for its infectious mononucleosis-like ● Culture method: Requires B-lymphocyte
illness. isolation
When immunocompromised hosts are infected
● Why B-lymphocyte isolation:
(children, post-transplant patients, HIV patients), it
○ Because Epstein-Barr virus is under
can be life threatening since CMV is a systemic
genus Lymphocryptovirus
disease (infects the organs like lungs, liver,
● Viral culture for EBV require human
intestinal tract, retina and CNS)
B-lymphocyte which is beyond the
● Best observed during the first 2 weeks of
capabilities of most clinical (urology)
life
laboratories
● When passed to a child, they can have
○ Instead of culture, they will just
mental retardation, deafness, or intellectual
undergo serological method
impairment.
● Congenital infection shows petechiae,

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● Serological method: Paul-Bunnel ● Usually cannot be detected after 6 months

Heterophile AB screening ● Patients have elevated IgG and IgA,
○ Anti-VCA: antibodies against the Anti-EA/D antibodies
viral capsid antigen:
■ IgM 4 weeks. IgG lifetime ○ Anti-EA/R: antibody to early
Anti-VCA restricted antigen:
● IgM occurs early in the infection ■ >2 years, Burkitt’s Lymphoma
● Disappears for about 4 weeks Anti-EA/R
● IgG is lifetime present ● Antibodies appear on acute phase and
disappears as soon as after Anti-EA/D
○ Anti-EA: antibody to early antigen: ● Can persist up to 2 years, and lifelong to
■ IgG <6 months some patients
Anti-EA ● Remain elevated when patient have
● Acute phase, current, or recent infection Burkitt’s lymphoma
● Anti-EA IgG usually cannot be detected in
serum after 6 months ○ Anti-EBNA: antibody to EBV nuclear
antigen:
○ Anti-EA/D: antibody to early di use ■ 6-12 months
antigen: Anti-EBNA
■ IgM >6 months ● Appears late
Anti-EA/D ● Occurs 1 month after infection
● Appear on 5th phase ● Titer peaks at 6-12 months (late reaction)
● Presence indicate current or recent
● Molecular method: qPCR
infections

sixth childhood rash. Infection is known by

HUMAN HERPESVIRUS 6
acute and febrile; maculopapular rash that
● MOT: Salivary contact, inhalation of appears as the fever resolves.
respiratory droplets from and close contact
Itchy rashes, not raised.
infected individual
● Allergy-like in the whole body, common to
● Incubation period: Ranges from 1 to 2
children
weeks
● Associated with progressive multifocal
2 variants for Herpesvirus 6 leukoencephalopathy and multiple sclerosis
1. Variant A
2. Variant B
○ Not distinguishable serologically
○ Usually, Variant B causes human
herpesvirus 6
● Nor herpesvirus 7 because it is the same as
herpesvirus 6
CLINICAL SIGNIFICANCE LABORATORY DIAGNOSIS
● Associated with childhood disease roseola ● Culture method: Most sensitive with
infantum (flower-like), exanthum subitem, lymphocyte cell culture
and sixth disease, reflecting its role as the ● Molecular method: PCR assay

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HUMAN HERPESVIRUS 8
● MOT: Sexual contact
CLINICAL SIGNIFICANCE
● Known for causing kaposi
sarcoma-associated herpesvirus that
shows development of primary e usion
lymphomas and multicentric castleman
disease
Kaposi Sarcoma
● Rare type of cancer that a ect the skin,
lymph nodes, and mucus membranes
LABORATORY DIAGNOSIS
● Sample: Tissues, blood, bone marrow
aspirate, saliva, semen
● Molecular method: PCR assay, in-site
hybridization
KAPOSI SARCOMA

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