470 Questions
What is the morphology of adenovirus?
Icosahedral, about 80-110 nm diameter
What is the genome of adenovirus?
dsDNA
How does adenovirus replicate?
In nucleus
What illnesses can adenoviruses cause?
Gastroenteritis, conjunctivitis, cystitis
How are adenoviruses mainly transmitted?
By respiratory or feco-oral contact from humans
Which specimens can be used for laboratory diagnosis of adenovirus?
Throat, eye, urine, feces
What is PCR?
A technique that amplifies a specific segment of DNA or RNA from a sample
What are the steps involved in PCR?
Denaturation, annealing, replication
What is the causative agent of measles?
Measles virus
What is the genome of rubella virus?
ssRNA
Which virus has a single-stranded, negative-sense RNA genome that encodes nine proteins?
Mumps virus
What is the name of the protein that binds to sialic acid receptors on host cells and facilitates virus attachment and entry for the mumps virus?
Hemagglutinin-neuraminidase
What is the name of the white spots inside the mouth that can indicate a measles infection?
Koplik's spot
Which virus is preventable by two doses of the mumps vaccine?
Mumps virus
What is the name of the virus that causes chickenpox?
Varicella zoster virus
How is chickenpox transmitted?
Through respiratory droplets or direct contact with an infected person
What are the initial signs and symptoms of mumps?
Muscle pain, headache, and feeling generally unwell
What is the name of the test that can diagnose mumps by testing the blister fluid or scabs?
PCR
What is a serious complication of measles that can lead to blindness?
Severe diarrhea
How can infants under one year of age gain some immunity to measles?
Through maternal antibodies
Which of the following best describes the structure of poxviruses?
Brick-shaped with a linear double-stranded DNA genome
How is smallpox virus transmitted?
Via respiratory aerosol or direct contact with virus in skin lesions
What is the pathogenicity of smallpox?
It infects the upper respiratory tract, local lymph nodes, internal organs, and then the skin
What are the symptoms of smallpox?
Fever, vomiting, and a skin rash
How is smallpox diagnosed in the laboratory?
By PCR and electron microscopy
What is the mode of replication of poxviruses?
Replication in the cytoplasm of the host cell
How is smallpox controlled?
By vaccination
What is the incubation period of smallpox?
7-17 days
Which of the following is a characteristic of smallpox skin lesions?
They are fluid-filled with a dent in the center
What is the primary site of smallpox infection?
The lungs
What is the size range of adenovirus?
80-110 nm
Which of the following illnesses can be caused by adenoviruses?
Gastroenteritis
What is the main mode of transmission of adenoviruses?
Airborne
What type of genetic material does adenovirus have?
dsDNA
What is the name of the technique that can detect the presence of pathogens and identify genetic variations?
PCR
Which of the following is a common complication of measles?
All of the above
What is the name of the virus that causes rubella?
Rubivirus
Which of the following specimens can be used for laboratory diagnosis of adenovirus?
Urine
What is the name of the enzyme that adds nucleotides to the primers during PCR?
Polymerase
What is the name of the virus that causes rubella?
Rubivirus
What is the morphology of poxviruses?
Brick-shaped
What is the primary mode of transmission of smallpox?
Respiratory aerosol
How is smallpox controlled?
By vaccination
What is the incubation period of smallpox?
7-17 days
What is the name of the test that can diagnose smallpox by detecting viral DNA?
PCR
What are the initial symptoms of smallpox?
Fever, vomiting, and sores in the mouth
What is the name of the virus that causes smallpox?
Smallpox virus
What is the mode of replication of smallpox virus?
Replication in the cytoplasm of the host cell
What is the name of the technique used to visualize poxviruses?
Electron microscopy
What is the name of the process by which smallpox virus is released from the host cell?
Budding
What is the main mode of transmission for measles?
Direct contact with mouth or nasal secretions
What is the name of the protein that facilitates virus attachment and entry for the mumps virus?
Hemagglutinin-neuraminidase (HN)
What is the name of the virus that causes chickenpox?
Varicella zoster virus (VZV)
What is the name of the test that can diagnose mumps by confirming the presence of the swollen glands?
Physical examination
What is the most common complication of measles that can lead to serious consequences such as blindness?
Encephalitis
What is the name of the glycoprotein that binds to sialic acid receptors on host cells and facilitates virus attachment and entry for the mumps virus?
Hemagglutinin-neuraminidase (HN)
What is the incubation period for chickenpox?
7-14 days
What is the name of the laboratory diagnosis method for measles that detects the presence of nucleic acid?
PCR
What is the name of the virus family that the mumps virus belongs to?
Paramyxoviridae
What is the name of the white spots inside the mouth that can indicate a measles infection?
Koplik's spot
Measles is a bacterial infection.
False
Mumps is caused by a virus with a single-stranded, negative-sense RNA genome.
True
The mumps virus has two glycoproteins: hemagglutinin-neuraminidase (HN) and fusion (F) protein.
True
Chickenpox is caused by the varicella zoster virus (VZV).
True
Chickenpox is not a highly contagious disease.
False
Measles can lead to serious complications such as ear infections, bronchitis, and miscarriage.
True
Mumps is preventable by one dose of the MMR vaccine.
False
The measles virus can be diagnosed by the presence of white spots inside the mouth called Koplik's spot.
True
PCR can be used for laboratory diagnosis of both measles and mumps.
True
Mumps can cause acute pancreatic inflammation as a complication.
True
Smallpox is caused by a group of viruses with a linear double-stranded RNA genome.
False
Poxviruses have a complex life cycle that involves replication in the nucleus of the host cell and release by exocytosis.
False
Smallpox virus can only be transmitted via respiratory aerosol.
False
Smallpox begins when the virus infects the lower respiratory tract and local lymph nodes.
False
Smallpox has an incubation period of 7-17 days and can cause fever, vomiting, sores in the mouth, and a skin rash.
True
The skin rash in smallpox turns into fluid-filled bumps without a dent in the center.
False
Smallpox can only spread between people and not through contaminated objects.
False
The laboratory diagnosis of smallpox can be done using PCR and electron microscopy.
True
Vaccination is not an effective way of controlling smallpox.
False
Poxviruses have a lipid membrane surrounding their protein core.
True
Adenoviruses can only cause respiratory illness.
False
Adenoviruses replicate in the cytoplasm.
False
Adenoviruses can be transmitted through fecal-oral contact.
True
PCR can only detect the presence of pathogens.
False
Measles and rubella are caused by the same type of virus.
False
Rubella virus has a positive-sense RNA genome.
False
The size range of adenovirus is between 80-110 nm in diameter.
True
Poxviruses have a helical structure.
False
Smallpox is caused by a single-stranded RNA virus.
False
Mumps primarily affects the respiratory system.
False
What is the genome of adenovirus?
dsDNA
What are the possible illnesses caused by adenoviruses?
respiratory system illness, gastroenteritis, conjunctivitis, cystitis
What is the control measure for adenoviruses?
vaccine (live)
What is PCR?
a technique that amplifies a specific segment of DNA or RNA from a sample
What are the steps involved in PCR?
Denaturation, Annealing, Extension
What type of virus is rubella?
single-stranded, negative-sense, enveloped RNA virus
What are the initial symptoms of rubella?
respiratory infection
What is the size range of adenovirus?
about 80-110 nm diameter
What is the transmission mode for rubella?
respiratory contact
What are the possible complications of measles?
ear infections, bronchitis, miscarriage
What is the morphology of poxviruses?
brick-shaped
What is the genome of poxviruses?
linear double-stranded DNA
How do poxviruses replicate?
in the cytoplasm of the host cell
How is smallpox virus transmitted?
respiratory aerosol or direct contact with virus in skin lesions
What is the pathogenicity of smallpox?
begins in upper respiratory tract and local lymph nodes, infects internal organs, spreads to skin
What are the symptoms of smallpox?
incubation period of 7-17 days, fever, vomiting, mouth sores, skin rash with fluid-filled bumps and scarring
How is smallpox diagnosed in the laboratory?
PCR and electron microscopy
What is the main method of controlling smallpox?
vaccination
What is the mode of release for poxviruses?
budding or cell lysis
Are poxviruses enveloped or non-enveloped viruses?
enveloped
What is the mode of transmission of measles?
Measles is an airborne disease which spreads easily through the coughs and sneezes of infected people. It may also be spread through direct contact with mouth or nasal secretions.
What are the serious complications that can arise from a measles infection?
Measles can lead to serious complications such as ear infections, bronchitis, miscarriage, low blood platelets, blindness, and severe diarrhea.
How can measles be diagnosed in a laboratory?
Measles infection can be diagnosed by the presence of white spots inside the mouth called Koplik's spots. Additionally, detection of nucleic acid (PCR) and detection of antigen can also be used for laboratory diagnosis.
How can newborn infants acquire some immunity to measles?
Mothers who are immune to measles pass antibodies to their children, which can give newborn infants some immunity.
What is the structure of the mumps virus?
The mumps virus has a single-stranded, negative-sense RNA genome that encodes nine proteins. The virus structure consists of a helical nucleocapsid core surrounded by a lipid bilayer membrane. The membrane contains two glycoproteins: hemagglutinin-neuraminidase (HN) and fusion (F) protein.
What is the primary mode of transmission of the mumps virus?
The mumps virus is transmitted by respiratory droplets or direct contact with an infected person.
What are the symptoms of a mumps infection?
Initial signs and symptoms of mumps often include fever, muscle pain, headache, and feeling generally unwell. This is then usually followed by painful swelling of one or both parotid salivary glands.
What are the complications that may arise from a mumps infection?
Complications of mumps may include painful testicular inflammation, ovarian inflammation, acute pancreatic inflammation, and brain inflammation.
How can chickenpox be transmitted?
Chickenpox is an airborne disease which spreads easily through the coughs and sneezes of an infected person. It may also be spread from one to two days before the rash appears until all lesions have crusted over. It may also spread through contact with the blisters.
What are the initial symptoms of a chickenpox infection?
Symptoms of chickenpox begin 10-21 days after exposure and include fever, fatigue, and headaches. The disease causes a skin rash that spreads to the rest of the body.
What are the common illnesses caused by adenoviruses?
Respiratory system illness, gastroenteritis, conjunctivitis, and cystitis.
What is the technique used for amplifying a specific segment of DNA or RNA from a sample?
Polymerase chain reaction (PCR).
What are the steps involved in the PCR procedure?
Denaturation, annealing, and extension. These steps are repeated multiple times to amplify the target DNA segment.
What is the structure of poxviruses and how do they replicate?
Poxviruses have a brick-shaped morphology and a linear double-stranded DNA genome. They replicate in the cytoplasm of the host cell and are released by budding or cell lysis.
What are the symptoms of smallpox and how is it transmitted?
Smallpox has an incubation period of 7-17 days and can cause fever, vomiting, sores in the mouth, and a skin rash. The virus is transmitted via respiratory aerosol or by direct contact with virus either in the skin lesions.
What is the laboratory diagnosis for smallpox and how can it be controlled?
The laboratory diagnosis for smallpox can be done using PCR and electron microscopy. Control can be achieved through vaccination.
What is the mode of transmission for chickenpox?
Chickenpox is transmitted through coughs and sneezes of an infected person, as well as contact with the blisters.
What are the symptoms of measles?
Measles symptoms include fever, cough, cold, red eyes, and rashes. It may also lead to serious complications such as ear infections, bronchitis, miscarriage, low blood platelets, blindness, and severe diarrhea.
What are the glycoproteins responsible for facilitating virus attachment and entry for the mumps virus?
The glycoproteins responsible for facilitating virus attachment and entry for the mumps virus are hemagglutinin-neuraminidase (HN) and fusion (F) protein.
How is mumps diagnosed and confirmed?
Mumps can be diagnosed based on a physical examination which confirms the presence of swollen salivary glands, and confirmed through PCR testing.
Adenoviruses are transmitted mainly by respiratory or feco-oral contact from ______.
humans
The genome of adenovirus is
dsDNA
The size range of adenovirus is approximately
80-110 nm diameter
Measles, or rubella, is a viral infection of the
respiratory system
The laboratory diagnosis method for measles that detects the presence of nucleic acid is
PCR
Rubella virus is a single-stranded, negative-sense, enveloped
RNA virus
PCR is widely used in molecular biology, biotechnology, medicine and
forensics
The vaccine for controlling adenovirus is
live
Smallpox virus is transmitted via respiratory ______ or by direct contact with virus either in the skin lesions.
aerosol
Poxviruses have a simple life cycle that involves replication in the ______ of the host cell and release by budding or cell lysis.
cytoplasm
Smallpox begins when the virus infects the upper respiratory tract and local lymph nodes and then enters the blood (primary ______).
viremia
It can spread between people or through ______ objects.
contaminated
Smallpox has an incubation period of 7-17 days and can cause fever, vomiting, sores in the mouth, and a ______ rash.
skin
Internal organs are infected; then the virus reenters the ______ (secondary viremia) and spreads to the skin.
blood
The skin rash turns into fluid-filled bumps with a dent in the center, which then scabbed over and fell off leaving ______.
scars
Poxviruses are a group of viruses that have a brick-shaped ______ and a linear double-stranded DNA genome.
morphology
Laboratory Diagnosis: PCR and ______ microscopy.
electron
Measles is a viral infection that causes fever, cough, cold, red eyes, and ______.
rashes
Mothers who are immune to measles pass antibodies to their children, which can give newborn infants some immunity. However, these antibodies gradually lose over the first nine months of life, making infants under one year of age susceptible to infection with the ______ virus.
measles
The mumps virus is a member of the ______ family of enveloped RNA viruses.
Paramyxoviridae
The HN protein binds to ______ receptors on host cells and facilitates virus attachment and entry.
sialic acid
Chickenpox is an airborne disease which spreads easily through the coughs and sneezes of an infected person. It may be spread from one to two days before the rash appears until all lesions have ______ over.
crusted
The disease causes a skin rash that spreads to the rest of the body, with other symptoms such as fever, fatigue, and ______.
headaches
Chickenpox is a highly contagious disease caused by the initial infection with ______ virus (VZV).
varicella zoster
Diagnosis by ______ testing of the blister fluid or scabs and serological tests.
(PCR)
What is the family of poliovirus?
Picornaviridae
What is the most common route of transmission for poliovirus?
Faecal-oral route
What is the rare paralytic illness caused by poliovirus?
Poliomyelitis
What is the type of immune response against poliovirus?
IgM and IgG
What are the two forms of poliovirus vaccine?
Inactivated and attenuated
What is the name of the scientist who developed the inactivated poliovirus vaccine (IPV)?
Jonas Salk
What is the advantage of oral poliovirus vaccine (OPV)?
Can be administered orally
What happens following vaccination with oral poliovirus vaccine (OPV)?
The vaccine virus replicates in the stomach
What is the main disadvantage of Oral Poliovirus Vaccine (OPV)?
It can cause paralysis in rare cases
What is a rare but serious complication that can develop in people with immunological deficiencies who receive OPV?
Vaccine-associated paralytic polio
What is the main advantage of IPV over OPV?
It does not cause vaccination-associated polio paralysis
What is a disadvantage of IPV compared to OPV?
It decreases intestinal immunity
What is the mode of administration for IPV?
Leg or arm injection
What is the mode of transmission for adenoviruses?
Airborne droplets
What is the laboratory diagnosis for poliovirus?
Isolating the virus in cell culture or its genome using PCR
What is the mode of transmission for chickenpox?
Airborne droplets
What is the diagnostic test for smallpox that detects viral DNA?
PCR
What is the mode of transmission of enteroviruses?
Ingestion of contaminated food or water
Which of the following is NOT a category of enteroviruses?
Rhinoviruses
What is the difference between a poliovirus and a non-polio enterovirus?
Polioviruses cause more severe diseases than non-polio enteroviruses
Which virus is often associated with hand, foot, and mouth disease?
Coxsackie A virus
What are the potential severe disorders that Coxsackie B viruses can cause?
Myocarditis, meningitis, and pancreatitis
What is the primary group of people who may have serious problems when infected with non-polio enteroviruses?
Babies and young children
What is the genetic material of enteroviruses?
Single-stranded RNA
What is the difference between Coxsackie A viruses and Coxsackie B viruses?
Coxsackie A viruses are associated with hand, foot, and mouth disease, while Coxsackie B viruses are associated with fever and rash
Poliovirus is mainly found in the respiratory system.
False
Poliovirus can cause nerve system disorders.
True
There are three serotypes of poliovirus.
True
The faecal-oral route is the most common mode of transmission of poliovirus.
True
Poliovirus infection is always symptomatic.
False
Poliovirus can cause paralytic illness when it replicates in motor neurons in the CNS.
True
Both IgG and IgA play a role in preventing re-infection with poliovirus.
True
OPV is more expensive than IPV.
False
OPV can cause paralysis in rare cases
True
People with immunological deficiencies may develop vaccine-associated paralytic polio
True
Vaccine-derived polioviruses are not circulating in the population
False
IPV includes all three poliovirus serotypes
True
IPV is administered through a nasal spray
False
IPV induces a stronger protective immune response than OPV does in the majority of individuals
True
IPV decreases intestinal immunity
True
Defects in IPV immunity allow wild poliovirus to remain in the intestine and be excreted in faeces
True
IPV is more than five times the cost of OPV
True
Enteroviruses belong to the Picornaviridae family and are members of group III Baltimore (-ssRNA)
False
The enteroviruses were divided into four categories: polioviruses, Coxsackie A viruses, Coxsackie B viruses, and echoviruses
True
A Coxsackie A virus, a Coxsackie B virus, and an echovirus are all called non-polio enteroviruses
True
Most people who get non-polio enteroviruses don't get sick, or they only get a little sick
True
Enteroviruses spread through the respiratory route
False
Coxsackie viruses are often associated with human hand, foot, and mouth disease
True
Echoviruses can cause more severe disorders such as myocarditis, meningitis, and pancreatitis
True
Adenovirus can be diagnosed by laboratory methods such as PCR and virus isolation
True
What are the four categories of enteroviruses?
polioviruses, Coxsackie A viruses (CA), Coxsackie B viruses (CB), and echoviruses
What is the fecal-oral route of transmission for enteroviruses?
spread through feces of an infected person to objects, food, or water that can then be ingested by another person.
What is the association between Coxsackie viruses and hand, foot, and mouth disease?
Coxsackie viruses are often associated with human hand, foot, and mouth disease.
What are the possible severe disorders caused by Coxsackie viruses?
myocarditis, meningitis, and pancreatitis.
What is the cause of many non-specific viral infections?
Echoviruses
Who is at risk of serious problems from non-polio enteroviruses?
babies and people with weak immune systems
What is the family and group classification of enteroviruses?
Picornaviridae family and group IV Baltimore (+ssRNA)
What is the difference between polioviruses and non-polio enteroviruses?
Polioviruses only include the three strains of the virus that cause polio, while non-polio enteroviruses include Coxsackie A viruses (CA), Coxsackie B viruses (CB), and echoviruses.
What is poliomyelitis?
Poliomyelitis is a rare paralytic illness caused by the poliovirus that affects the nervous system and may cause short or long term paralysis.
What are the two forms of poliovirus vaccine?
The two forms of poliovirus vaccine are live attenuated (OPV) and inactivated (IPV).
Who developed the OPV vaccine?
Albert Sabin successfully developed the OPV (also known as the Sabin vaccination) in 1961.
Who developed the IPV vaccine?
Jonas Salk developed IPV and it became widely used in 1955.
What is the main mode of transmission for poliovirus?
The faecal-oral route of transmission is more prevalent than the respiratory route for the spread of poliovirus. The virus is spread by the faeces of infected people.
What are the three serotypes of poliovirus?
There are three serotypes of poliovirus, and various laboratory techniques can differentiate them.
What is the advantage of OPV vaccine?
The main advantages of OPV vaccine are that it is administered orally, is free, and can be administered by volunteers without the need for sterile injection equipment or qualified health personnel.
What is the immune response to poliovirus infection?
There is an initial specific IgM response, followed by IgG. IgG in the blood and IgA on mucosal surfaces both play a function in avoiding re-infection. However, antibodies directed against one serotype may not provide protection against the other.
What are the potential risks associated with the live attenuated vaccination virus in OPV?
It can cause paralysis in rare cases (1 in 2.7 million) and vaccine-derived polioviruses may genetically mutate and begin spreading throughout a population.
What is the method of administration for IPV?
It is administered through a leg or arm injection.
What are the advantages of IPV over OPV?
IPV induces a stronger protective immune response in the majority of individuals and there is no danger of vaccination-associated polio paralysis.
What are the disadvantages of IPV?
IPV decreases intestinal immunity, allowing wild (infectious) poliovirus to remain in the intestine and be excreted in faeces, and it is more than five times the cost of OPV.
What are the possible ways of diagnosing poliovirus?
Poliovirus can be found using an electron microscope in the throat, faeces, and occasionally cerebrospinal fluid (CSF) specimens, or by isolating the virus in cell culture or its genome using polymerase chain reaction (PCR). Patients' blood samples may be tested for IgM and IgG antibodies by ELISA.
How does IPV affect intestinal immunity?
Defects in IPV immunity allow wild (infectious) poliovirus to remain in the intestine and be excreted in faeces, which might infect other individuals again.
What is the cost difference between IPV and OPV?
IPV is more than five times the cost of OPV.
What is the possible complication that may arise in people with immunological deficiencies after receiving OPV?
They may develop vaccine-associated paralytic polio.
What is the name of the laboratory diagnosis method for determining whether a patient has paralytic poliomyelitis?
Serology may be useful in determining whether a patient has paralytic poliomyelitis, especially if the patient has not been vaccinated.
• Enteroviruses spread through the ______ route.
fecal-oral
• Coxsackie viruses are often associated with human hand, foot, and mouth disease. Additionally, Coxsackie B viruses may result in a fever, a slight rash, and mild upper respiratory tract (URT) ______.
illness
• Echoviruses are a cause of many of the ______ viral infections.
non-specific
• A Coxsackie A virus, a Coxsackie B virus, and an echovirus are all called ______ enteroviruses.
non-polio
• But these viruses may also cause more severe disorders, such as myocarditis; meningitis; and ______.
pancreatitis
• Most people who get ______ enteroviruses don't get sick, or they only get a little sick.
non-polio
• Enteroviruses are RNA viruses that belong to the ______ family and are members of group IV Baltimore (+ssRNA).
Picornaviridae
• The enteroviruses were divided into four categories, namely, polioviruses, Coxsackie A viruses (CA), Coxsackie B viruses (CB), and ______.
echoviruses
OPV may cause paralysis in rare cases (1 in 2.7 million) and people with immunological deficiencies may develop vaccine-associated paralytic ______.
polio
Rarely, the vaccination virus may genetically mutate and begin spreading throughout a population. Vaccine-derived ______ are circulating in the population.
polioviruses
IPV is administered through a leg or arm ______.
injection
Because it is a non-live vaccine, there is no danger of vaccination-associated ______ paralysis.
polio
IPV decreases intestinal ______.
immunity
Defects in IPV immunity allow wild (infectious) poliovirus to remain in the intestine and be excreted in faeces, which might infect other individuals again. IPV is more than five times the cost of ______.
OPV
Poliovirus can be found using an electron microscope in the throat, faeces, and occasionally cerebrospinal fluid (CSF) specimens, or by isolating the virus in cell culture or its genome using polymerase chain reaction (______).
PCR
A serum sample should be taken early in the illness process, and a second sample (verified) should be obtained at least three weeks ______.
later
Serology may be useful in determining whether a patient has paralytic poliomyelitis, especially if the patient has not been ______.
vaccinated
• Poliovirus primarily replicates in ______ neurons in the spinal cord, brain stem, or motor cortex
motor
• Poliovirus is mainly transmitted through the ______-oral route
faecal
• The initial immune response to poliovirus involves the production of ______ antibodies, followed by IgG
IgM
• There are ______ serotypes of poliovirus
three
• IPV was developed by ______
Jonas Salk
• Vaccination timetables for poliovirus typically include ______ doses
four
• OPV is a vaccine that can induce a ______ immune response in the intestines' mucous membrane
mucosal
• The two forms of poliovirus vaccine are live attenuated (OPV) and ______
inactivated
Pseudohyphae differ from true hyphae in that they are constricted at the septa, form branches that begin with septation, and have terminal cells smaller than other cells. True hyphae are found in ______ fungi.
perfect
Aerial hyphae extend above the agar or nutrient substrate, and their function is to support reproductive structures called ______.
conidia
Conidia are spore like asexual reproductive structures not produced by cleavage, conjugation, or free-cell formation. Conidia are only formed by the ______ fungi.
imperfect
Arthroconidia are conidia resulting from the fragmentation of ______ into individual cells.
hyphae
Phialoconidia are ______-shaped conidia that can be branched.
tube
Fungi that reproduce sexually are called ______ fungi.
perfect
A selective agar used to recover cyclohexamide-sensitive ______ is Inhibitory mold agar (IMA)
Cryptococcus
Fungal cultures are incubated at ______°C
30
The ______ method is used to transfer aerial hyphae from the colony to a microscope slide for examination
Cellophane tape
Differential agars are used to enhance pigment development, conidia production, and mold-to-yeast phase transition. Potato dextrose agar (PDA) is used to enhance ______ development
conidia
The slide culture technique uses an agar block covered by a cover slip. On the side of the agar block, fungi are grown as ______
colonies
Brain heart infusion agar with blood (BHIB) is used to grow most fungi, especially those from ______ body sites
sterile
DIRECT EXAMINATION METHODS Calcofluor white stain is a fluorochrome that stains ______ found in the cell wall of fungi.
chitin
BODY SITES AND POSSIBLE FUNGAL PATHOGENS Microsporum and Trichophyton can be found in ______.
hair
BODY SITES AND POSSIBLE FUNGAL PATHOGENS ______ can be found in the lungs.
Candida albicans, Aspergillus, Rhizopus, Penicillium, Histoplasma capsulatum, Blastomyces dermatitidis, and Coccidioides immitis
DIRECT EXAMINATION METHODS India ink can be used to reveal capsules surrounding C. neoformans found in cerebrospinal fluid (CSF). However, due to low sensitivity, direct ______ detection assays have generally replaced the India ink wet mount.
antigen
BODY SITES AND POSSIBLE FUNGAL PATHOGENS ______ can be found in the genital tract.
Candida albicans
DIRECT EXAMINATION METHODS Fungal antigen detection uses known antibodies to identify circulating fungal antigens in a patient’s serum, CSF, or ______.
urine
DIRECT EXAMINATION METHODS Potassium hydroxide (KOH) is used to dissolve non-fungal materials in skin, nail, and hair samples. Specimen is placed on a slide, a drop of 10-20% KOH is added and covered with a coverslip, left for 20 min in incubator at 37°C to digest keratin. Then examined ______.
microscopically
Mycology is the study of fungi (molds, yeasts, and ______)
mushrooms
Fungi that show both a non molds (e.g., yeast) and molds phase
dimorphic fungi
Ergosterol = Major membrane sterol. Imidazole antifungals inhibit synthesis of ______. Polyene antifungals bind more tightly to ______ than cholesterol.
ergosterol
There are two main types of . Septate ______ have cellular separation or cross-walls. Sparsely septate (formerly aseptate) ______ contain few if any cellular separations. Pseudo are a chain of cells formed by budding that resemble true ______.
hyphae
All fungi are ______ (e.g., true nucleus, 80S ribosomes, mitochondria, as are humans). Complex carbohydrate cell walls: chitin, glucan, and mannan.
eukaryotic
Saprobe: Organism capable of living on decaying organic material.
saprobe
What is mycology?
The study of fungi
What is mycosis?
A fungal infection
What is the difference between molds and yeasts?
Molds are multicellular and yeasts are single-cellular
What is the major membrane sterol in fungi?
Ergosterol
What are dimorphic fungi?
Fungi that show both a non molds (e.g., yeast) and molds phase
What is the difference between septate and sparsely septate hyphae?
Septate hyphae have cellular separation or cross-walls, while sparsely septate hyphae contain few if any cellular separations
What is a saprobe?
An organism capable of living on decaying organic material
What is the main difference between pseudohyphae and true hyphae?
True hyphae are constricted at the septa, form branches that begin with septation, and have terminal cells smaller than other cells
What is the function of aerial hyphae?
To support reproductive structures called conidia
What are conidia?
Spore-like asexual reproductive structures not produced by cleavage, conjugation, or free-cell formation
What is the difference between microconidia and macroconidia?
Microconidia are single-celled, small conidia, while macroconidia are multicellular, large conidia
What is the name for conidia resulting from the fragmentation of hyphae into individual cells?
Arthroconidia
What are the two types of spores produced through sexual reproduction?
Ascospores and basidiospores
What is the term for fungi that undergo asexual reproduction?
Imperfect fungi
What method is used to diagnose vaginitis through the viewing of fungal elements such as hyphae, conidia, and budding yeasts?
Saline wet mount
What is the purpose of adding KOH to a specimen in a KOH mount?
To dissolve non-fungal materials
What body site can India ink be used to reveal capsules surrounding C. neoformans found in cerebrospinal fluid (CSF)?
Cerebrospinal Fluid
What is the purpose of adding KOH to clear the specimen of cellular debris in a Calcofluor white stain?
To dissolve non-fungal materials
What is the purpose of fungal antigen detection?
To identify circulating fungal antigens in a patient's serum, CSF, or urine
What fungal pathogen can be found in hair samples?
Microsporum
What fungal pathogen can be found in skin samples?
Candida albicans
What fungal pathogen can be found in urine samples?
Candida albicans
What fungal pathogen can be found in the genital tract?
Candida albicans
What is the pH of Modified SDA (Emmons) and how does it compare to other media in terms of bacterial inhibition?
Neutral pH and less inhibitory for bacteria than other media
What is Sabouraud-brain heart infusion agar (SABHI) used for and how can it be made selective for dimorphic fungi?
Selective medium for dimorphic fungi; addition of cyclohexamide, chloramphenicol, and gentamicin
What is the purpose of inhibitory mold agar (IMA) and what does it contain?
Used to grow most fungal pathogens; contains cyclohexamide and gentamicin
What is the purpose of the cellophane tape method in obtaining culture material for slide preparation?
To transfer aerial hyphae from the colony to a microscope slide
What is the temperature range for incubating fungal cultures?
25-30°C
What is the purpose of differential agars in fungal culture?
To enhance the growth of specific fungal pathogens
What is the purpose of brain heart infusion agar with blood (BHIB) and how can it be made selective for dimorphic fungi?
Used to grow most fungi, especially those from sterile body sites; addition of cyclohexamide, chloramphenicol, and gentamicin
Pseudohyphae are not constricted at the septa
False
Aerial hyphae support reproductive structures called conidia
True
Conidia are only formed by the perfect fungi
False
Chlamydoconidia are found in yeasts, whereas similar structures are found in moulds
False
Phialoconidia are not branched
False
Oospores result from the fusion of cells from two different hyphae
True
Sabouraud dextrose agar is a nutritionally rich medium
False
Saline wet mount is primarily used to diagnose vaginitis.
True
Lactophenol cotton blue wet mount is used to view fungal elements in culture isolates.
True
KOH mount dissolves fungi and keratin.
False
Gram stain can be used to view fungal yeasts.
True
India ink wet mount is still commonly used to diagnose Cryptococcus neoformans in CSF.
False
Calcofluor white stain is not absorbed by human tissue.
True
Fungal antigen detection is not reliable in immunocompromised patients.
False
Candida spp. can be found in both blood and urine.
True
Microsporum and Trichophyton are commonly found in hair.
True
Modified SDA (Emmons) is more inhibitory for bacteria than fungi.
False
Sabouraud-brain heart infusion agar (SABHI) is a selective medium for dimorphic fungi.
False
Brain heart infusion agar with blood (BHIB) can be made selective for dimorphic fungi by the addition of cyclohexamide, chloramphenicol, and gentamicin.
True
Inhibitory mold agar (IMA) is used to recover the cyclohexamide-resistant Cryptococcus.
False
Potato dextrose agar (PDA) enhances pigment development of Trichophyton rubrum.
True
Fungal cultures are incubated at 25°C.
False
The slide culture technique uses an agar block covered by a cover slip to grow fungi colonies.
True
Systemic mycosis is a fungal infection that affects multiple organs in the body.
True
Pseudohyphae are long, branching filaments that come together to form the mycelium.
False
Molds are single-cell fungi.
False
Imidazole antifungals inhibit the synthesis of ergosterol in fungi.
True
All fungi have complex carbohydrate cell walls made of chitin, glucan, and mannan.
True
Opportunistic mycosis primarily affects immunocompromised patients.
True
Dimorphic fungi only exist in a non-mold phase.
False
What is mycology?
The study of fungi (molds, yeasts, and mushrooms).
What are the general characteristics of fungi?
Eukaryotic, have complex carbohydrate cell walls, and contain ergosterol as a major membrane sterol.
What is mycosis?
Fungal infection.
What is a systemic mycosis?
A multiorgan infection caused by fungi.
What are opportunistic mycoses?
Fungal diseases that occur primarily in immunocompromised patients.
What are dimorphic fungi?
Fungi that show both a non molds (e.g., yeast) and molds phase.
What are hyphae and what are the two main types?
Hyphae are long, branching filaments that come together to form the mycelium. The two main types are septate hyphae and sparsely septate (formerly aseptate) hyphae.
What is the advantage of Modified SDA (Emmons) over other media for fungal growth?
It has a neutral pH and better supports the growth of fungi but is less inhibitory for bacteria.
What is Sabouraud-brain heart infusion agar (SABHI) and how can it be made selective for dimorphic fungi?
It is a nonselective medium for isolation of all fungi. It contains dextrose, peptone, and brain heart infusion. It can be made selective for dimorphic fungi by the addition of cyclohexamide, chloramphenicol, and gentamicin.
What is the purpose of Brain heart infusion agar with blood (BHIB)?
It is used to grow most fungi, especially those from sterile body sites.
What is the function of Cyclohexamide, chloramphenicol, and gentamicin in BHIB?
Cyclohexamide inhibits the saprophytic fungi and chloramphenicol inhibits many gram-positive and gram-negative bacteria, whereas gentamicin inhibits primarily gram-negative bacteria.
What is the purpose of Selective agars and give an example?
They contain various antimicrobial agents that will enhance the growth of specific fungal pathogens and will inhibit bacteria and other undesired growth. Inhibitory mold agar (IMA) is an example.
What is the Tease mount method and what is its disadvantage?
It is a technique used to obtain culture material for slide preparation. A dissecting needle is used to separate a fungal colony that has been placed on a microscope slide. Using this method may cause fungus, especially conidia, to be damaged. It may take more than one attempt to obtain a sample containing whole conidia.
What is the Slide Culture Method and how does it work?
It is a technique that uses an agar block covered by a cover slip. On the side of the agar block, fungi are grown as colonies. The coverslip is removed and used for examination under the microscope. This method prevents structural damage to the fungus.
What are the two types of hyphae and their functions?
Vegetative hyphae function in food absorption and are the portion that extends below the agar surface or nutrient substrate. Aerial hyphae extend above the agar or nutrient substrate, and their function is to support reproductive structures called conidia.
What are conidia and how are they classified based on morphology?
Conidia are spore-like asexual reproductive structures not produced by cleavage, conjugation, or free-cell formation. Conidia classification is based on conidia morphologic development. Microconidia are single-celled, small conidia. Macroconidia are multicellular, large conidia.
What are the types of conidia and how are they formed?
Arthroconidia are conidia resulting from the fragmentation of hyphae into individual cells. Blastoconidia form as the result of budding. Chlamydoconidia result from terminal cells in the hyphae that enlarge and have thick walls. Poroconidia are conidia formed by being pushed through a small pore in the parent cell. Phialoconidia are tube-shaped conidia that can be branched. Annelloconidia are vase-shaped conidia; the remaining parent outer cell wall takes on a saw-toothed appearance as the conidia are released.
What is the difference between perfect and imperfect fungi?
Fungi that reproduce sexually are called 'perfect fungi.' Fungi that undergo asexual reproduction are termed 'imperfect fungi.' Imperfect fungi are the only fungal group to produce conidia.
What are the four types of spores and how are they produced?
Ascospores are spores contained in a saclike structure. Basidiospores are spores contained in a club-shaped structure. Oospores are spores resulting from the fusion of cells from two different Hyphae. Zygospores are spores resulting from the fusion of two identical hyphae.
What is Sabouraud dextrose agar (SDA) and what is its purpose in fungal culture and isolation?
Sabouraud dextrose agar (SDA) is a general-purpose, nutritionally poor medium mildly selective for fungi, no longer commonly used; several different formulations available. In one formulation, the agar has an acidic pH (5.6) that inhibits most bacteria.
What is the difference between pseudohyphae and true hyphae?
Pseudohyphae differ from true hyphae in that they are constricted at the septa, form branches that begin with septation, and have terminal cells smaller than other cells.
What is the purpose of a saline wet mount examination?
To view fungal elements, such as hyphae, conidia, and budding yeasts.
What is the most common use of a saline wet mount?
To diagnose vaginitis.
What is the purpose of a lactophenol cotton blue wet mount?
To stain and preserve fungal elements in culture isolates.
What is the purpose of potassium hydroxide (KOH) in direct examination methods?
To dissolve non-fungal materials in skin, nail, and hair samples.
How long is a specimen left in an incubator at 37°C for a KOH mount?
20 minutes.
What is the purpose of a Gram stain in direct examination methods?
To view yeasts.
What is revealed by an India ink wet mount?
Capsules surrounding C. neoformans found in cerebrospinal fluid (CSF).
What is calcofluor white stain used for?
To stain chitin found in the cell wall of fungi.
What is the purpose of fungal antigen detection?
To identify circulating fungal antigens in a patient’s serum, CSF, or urine.
Which of the following is a common cause of yeast infections in women and UTIs?
Candida albicans
Which method is used to identify yeast through the visualization of budding yeast in saline wet mounts and Gram stains?
Microscopic appearance
What is the temperature range for yeast growth on Sabouraud-brain heart infusion agar?
22-30°C
Which agar is used to differentiate Candida spp. by enhancing the formation of fungal elements such as hyphae, pseudohyphae, and conidia?
Cornmeal agar with Tween 80
Which species of yeast does not produce chlamydospores and typically produces long-branched pseudohyphae?
Candida tropicalis
What is the most common cause of yeast infections and UTIs in women?
Candida albicans
What is the purpose of India ink preparations in yeast identification?
To show the capsule surrounding Cryptococcus neoformans
Which yeast species will show chlamydospores with clusters of blastoconidia along the hyphae?
Candida albicans
Which agar is commonly used for yeast culturing and can also resemble Staphylococcus colonies on blood agar?
Sabouraud-brain heart infusion agar
What type of infection can yeast cause in newborns?
Meningitis
What is the difference between germ tubes and pseudohyphae?
Germ tubes are non-septate and do not constrict at their point of origin while pseudohyphae are septate and constricted at their point of origin
What is the purpose of the carbohydrate assimilation test?
To determine the aerobic utilization of carbohydrates
What is the purpose of the urease test?
To identify Cryptococcus spp.
What is the purpose of CHROMagars?
To identify several species of yeasts
What is the procedure for germ tube production?
Yeasts are incubated with serum at 37°C for up to 3 hours and examined for germ tube production
What is the negative control used for the urease test?
Candida tropicalis
What is the difference between a positive germ tube and a pseudogerm tube?
A positive germ tube has no constriction at its base while a pseudogerm tube shows constriction at the base of the germ tube
What is the medium used in the carbohydrate assimilation test?
Agar slants containing various carbohydrates
What is the difference between germ tubes and hyphae?
Germ tubes are septate and constricted at their point of origin while hyphae are non-septate and do not constrict at their point of origin
What is the procedure for the germ tube production test?
Yeasts are incubated with serum at 37°C for up to 3 hours and examined for germ tube production
Yeasts can only cause vaginitis and UTIs in women.
False
Candida albicans is the most common cause of yeast infections.
True
India ink preparations are used to differentiate Candida spp.
False
Yeast colonies on Sabouraud-brain heart infusion agar are cream-colored and smooth.
True
Cornmeal agar with Tween 80 is used to differentiate Candida spp. by enhancing the formation of fungal elements.
True
Candida tropicalis typically produces long-branched pseudohyphae.
True
Candida albicans will show chlamydospores with clusters of blastoconidia along the hyphae.
True
Yeast colonies on blood agar can resemble Staphylococcus colonies.
True
Yeast infections can cause meningitis.
True
Budding yeast can be seen in saline wet mounts and Gram stains.
True
True or false: Germ tubes are hyphae-like extensions of young yeast cells that are septate and constricted at their point of origin.
False
True or false: Pseudohyphae are non-septate and do not constrict at their point of origin.
False
True or false: Candida tropicalis is a positive control for germ tube production.
False
True or false: Carbohydrate assimilation tests determine the anaerobic utilization of carbohydrates.
False
True or false: The pH indicator bromcresol purple is used in carbohydrate assimilation tests.
True
True or false: CHROMagars allow for the identification of only one species of yeast.
False
True or false: Calcofluor white stain is a fluorochrome that stains chitin found in the cell wall of fungi.
True
True or false: Coxsackie A viruses are typically associated with hand, foot, and mouth disease.
True
True or false: Chlamydoconidia are found in both yeasts and molds.
False
True or false: PCR stands for polymerase chain reaction and is used to amplify small amounts of DNA.
True
What are some common diseases caused by yeasts in both healthy and immunosuppressed individuals?
Yeasts can cause vaginitis, urinary tract infections (UTIs), newborn infections, and meningitis.
What is the most common cause of yeast infections?
The most common cause of yeast infections is Candida albicans.
What are the methods for identifying yeasts?
Microscopic appearance and culturing are the main methods for identifying yeasts.
What does the microscopic appearance of yeasts look like under saline wet mounts and Gram stains?
Saline wet mounts and Gram stains will show budding yeast.
What type of agar is used to culture yeasts?
Yeasts are grown on Sabouraud-brain heart infusion agar at 22-30°C.
What is the purpose of cornmeal agar with Tween 80 in differentiating Candida spp.?
Cornmeal agar with Tween 80 is used to differentiate Candida spp. by enhancing the formation of fungal elements such as hyphae, pseudohyphae, and conidia.
What does Candida albicans look like on cornmeal agar?
Candida albicans will show chlamydospores with clusters of blastoconidia along the hyphae.
What is the typical appearance of Candida tropicalis on cornmeal agar?
Candida tropicalis typically produces long-branched pseudohyphae. Blastoconidia are produced singly or in short chains. This species does not produce chlamydospores.
What is the purpose of India ink preparations in identifying yeasts?
India ink preparations are used to show the capsule surrounding Cryptococcus neoformans.
What do yeast colonies look like on Sabouraud-brain heart infusion agar?
Yeasts will form cream-colored, mucoid to smooth colonies within several days.
What are germ tubes and how do they differ from pseudohyphae?
Germ tubes are hyphae-like extensions of young yeast cells that are non-septate and do not constrict at their point of origin. Pseudohyphae look like germ tubes but are septate and constricted at their point of origin.
What is the procedure for germ tube production and which yeast is positive for germ tube production?
Yeast cells are incubated with serum at 37°C for up to 3 hours and examined for germ tube production. Candida albicans is positive for germ tube production.
What is the purpose of the carbohydrate assimilation test and how is it performed?
The carbohydrate assimilation test determines the aerobic utilization of carbohydrates by inoculating agar slants containing various carbohydrates with yeast suspended in saline. The medium contains the pH indicator bromcresol purple, and the tubes are incubated at room temperature and read after 14 days. The use of the carbohydrates results in the formation of yellow colonies.
What is the urease test used for and which yeast is used for the negative control?
The urease test is used to identify Cryptococcus spp., which are urease positive. C. albicans is used for the negative control.
What are CHROMagars and how do they aid in yeast identification?
CHROMagars are media that allow for the identification of several species of yeasts by containing a variety of substrates. The ability to metabolize different substrates results in the production of colonies of different colors.
What is the difference between Candida albicans and Candida tropicalis in terms of germ tube production?
C. albicans is positive for germ tube production, while C. tropicalis is used for the negative control but some strains can produce germ tubes if incubated over 3 hours.
What is the characteristic appearance of a positive germ tube?
A positive germ tube has no constriction at its base.
What is the characteristic appearance of a pseudogerm tube?
A pseudogerm tube shows constriction at the base of the germ tube.
What is the main difference between germ tubes and hyphae?
Germ tubes are hyphae-like extensions of young yeast cells that are non-septate and do not constrict at their point of origin, while hyphae are filaments of cells that have septa and may constrict at their point of origin.
What is the difference between a germ tube and a pseudohypha in terms of septation and constriction?
Germ tubes are non-septate and do not constrict at their point of origin, while pseudohyphae are septate and constricted at their point of origin.
Yeasts are common causes of ______ and urinary tract infections (UTIs) in Women and can cause a number of other diseases in healthy and immunosuppressed individuals.
vaginitis
The most common cause of yeast infections is ______ albicans.
Candida
Saline wet mounts and Gram stains will show ______ yeast.
budding
Yeasts will form cream-colored, mucoid to smooth colonies within several days on ______ agar.
Sabouraud-brain heart infusion
Cornmeal agar with Tween 80 is used to differentiate Candida spp. by enhancing the formation of fungal elements such as hyphae, pseudohyphae, and ______.
conidia
Candida albicans will show ______ with clusters of blastoconidia along the hyphae.
chlamydospores
Candida tropicalis typically produces long-branched ______.
pseudohyphae
Yeasts can cause ______ infections and meningitis in newborns.
newborn
India ink preparations are used to show the capsule surrounding ______ neoformans.
Cryptococcus
On ______ agar, yeast colonies can resemble Staphylococcus colonies.
blood
Germ tubes are hyphae like extensions of young yeast cells showing parallel sides, are non - septate (showing no cell wall division), and will not constrict at their point of origin. Pseudohyphae look like germ tubes but are ______ and constricted at their point of origin.
septate
Yeasts are incubated with serum at 37°C for up to 3 hours and examined for ______ production.
germ tube
C. albicans is positive for ______ production.
germ tube
Assimilation tests determine the aerobic utilization of ______.
carbohydrates
Agar slants containing various carbohydrates are inoculated with yeast suspended in ______.
saline
The tubes are incubated at ______ temperature and read 14 days.
room
A positive urease is indicated by a ______ to purple color.
pink
CHROMagars allow for the identification of several species of ______.
yeasts
The media contain a variety of ______.
substrates
The ability to metabolize different substrates results in the production of colonies of different ______.
colors
What is the most prevalent yeast isolate and the causal agent of candidiasis?
Candida albicans
Where is Candida albicans a natural component of the flora?
Both respiratory/gastrointestinal and female genital tracts
What is the most common source of Candida infections in newborns?
Exogenous infections
Which Candida species is commonly found in soil, water, and the digestive, urinary, and respiratory tracts?
Candida tropicalis
What are some common risk factors for Candida infections?
Burns, wounds, diabetes, antibiotic medication, pregnancy, and immunological disorders
Which type of candidiasis affects the oral cavity?
Thrush
What types of infections can Candida albicans cause?
Meningitis, UTIs, and heart and lung infections
Which agar is commonly used to culture Candida albicans?
Sabouraud agar
What is the most common cause of Candida infections in adults?
Endogenous infections
Which Candida species is commonly found in food such as dairy and beer?
Candida krusei
What is the characteristic appearance of yeast cells when stained with Gram stain?
Round and irregular in size
Which Candida species is positive for germ tube and can form chlamydospores?
C. dubliniensis
Which of the following is a possible complication of cryptococcosis in immunocompromised patients?
Systemic infections and meningitis
What is the mode of transmission of Cryptococcus neoformans?
Inhalation of bird droppings or contaminated materials
Which Trichosporon species is associated with human hair infection white piedra and systemic disease referred to as trichosporonosis?
T. beigelii
What is the characteristic appearance of Trichosporon species on lactophenol cotton blue preparation?
Hyaline hyphae with blastoconidia and arthroconidia
Which of the following is a characteristic of Rhodotorula that distinguishes it from Cryptococcus?
Inositol negative
What is the usual habitat of Rhodotorula?
Moist environments such as on shower curtains and toothbrushes
What is the biochemical characteristic of Trichosporon species?
Positive for nitrate reduction
What test can be performed on CSF and serum specimens for the direct detection of cryptococcal antigen?
Direct antigen test for cryptococcal antigen
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