Microbiology Exam 4 Flashcards
1
Q
This spirochete is contracted by direct contact with a painless, small round, and firm infectious lesion (chancre). The onset of symptoms ranges from 10-90 days and without treatment this spirochete could cause secondary sx ( widespread rash) and tertiary sx ( multi-organ).
A
- Treponema pallidum
2
Q
Syphilis
A
- Treponema pallidum
3
Q
Which spirochete causes Lyme Disease (target sign) from prolonged association with deer tick bite exposure (24+ hrs)?
A
- Borrelia burgdorferi
4
Q
What could cause a red macule, expanding rash, and neurologic or cardiac involvement (encephalitis, facial palsy, etc)?
A
- Borrelia burgdorferi
Lyme disease
5
Q
Deer ticks may cause what disease?
A
- Lyme Disease from Borrelia burgdorferi
6
Q
What spirochete transmits through contact with the urine of infected animals via contaminated water or moist soil? Causing fever, headache, myalgia, and chills leading to renal and liver failure.
A
- Leptospira interrogans
Leptospirosis
7
Q
What causes leptospirosis?
A
- Leptospira interrgoans
8
Q
GNB BTA that causes Melioidosis, especially persons with a pre-existing major illness.
A
- Burkholderia pseudomallei (B. pseudomallei)
9
Q
Endemic in Southeast Asia, N. Australia, & South Pacific.
Transmitted by direct contact with contaminated soil and surface water causing acute pulmonary infection; acute localized infection (ulcer/nodule/abscess), septicemia, multiple organ involvement. Symptoms often appear 2-4 weeks after exposure or maybe subclinical and/or delayed (years). What etiologic agent is described?
A
- Burkholderia pseudomallei (B. pseudomallei)
10
Q
Which BTA is endemic to parts of Africa, Asia, Middle East, & S. America (eradicated from N. America & Europe). Transmitted from animals to humans (rare) via contact with blood and body fluids into skin abrasions or mucosal surfaces (not environmental sources)
• Affects lungs & airways; causes septicemia, cutaneous lesions, liver, spleen, fever
• Fatality rate 95% in untreated; 50% in treated
A
- Burkholderia mallei (B. mallei)
11
Q
What infrequent pathogen causes pneumonia in immunocompromised or cystic fibrosis patients?
A
- Burkholderia cepacia
Transmission through Soil & water source – very hardy; challenging hospital control
12
Q
Which very-low-frequency etiologic agent is a GPC in chains that causes generalized necrotizing soft tissue infections, including Pelvic Inflammatory Disease; bone & joint, and other infections?
A
- Peptostreptococcus
13
Q
Anaerobic bacteria that is normal microbiota of the vagina, GI, and skin?
A
- Peptostreptococcus
GPC, chains
14
Q
Name the etiologic agent.
- Very low frequency
- Gram-negative bacilli
- Anaerobic
- Periodontal infections, skin ulcers
A
- Fusobacterium
15
Q
Lower levels of this etiologic agent in the gut may be associated with clinical disorders?
A
- Facalilbacterium
16
Q
Which etiologic agent is an abundant normal microbiota of gut, vagina, mouth and an important component of probiotics?
A
- Bifidobacterium
Gram-positive bacilli, often branched, non-sporeforming
Anaerobic
17
Q
Name the etiologic agent described.
- Gram-positive bacillus, non-sporeforming
- Anaerobic
- An abundant normal gut microbiota; may boost immune system.
A
- Facalilbacterium
18
Q
Which virus is transmitted by droplets and contact (especially hands) and by inhalation of droplets, causing cough, runny nose, generalized aches & muscle pain, fever (possible nausea & vomiting in children probably due to fever)?
- Incubation 1-2 days; symptoms 5-7 days (cough 7-14 days)
- Viral Pneumonia (about 10% of admissions) – high mortality
- Secondary Bacterial Pneumonia sometimes follows viral URT infections
A
- Influenza virus
19
Q
Which virus structure is described below?
Core with 8 strands of RNA, Enveloped
- Lipid bilayer from previous host cell (animal specific or adapted to other types of cells)
- Contains Hemagglutinin and Neuraminidase – used for attachment and virulence
- Matrix protein (capsid)
Antigenic Types Include (A, B, C)
- Types based on surface antigens Hemagglutinin (H) and Neuraminidase (N)
- Animal strain based on original “source” of viral envelope
- Infectivity of animal virus to humans is due to adaptation to enter human cell membranes
A
- Influenza virus
20
Q
Virulence factors of this virus include:
- High rate of gene recombination and mutation – New major antigenic types & subtypes sweep the world every 2-4 years
- Surface antigen changes due to:
(a) Gene recombination – recombination of 8 strands of RNA
(b) Gene mutation – causes genetic shift and drift - Hemagglutinin and Neuraminidase are factors both of attachment and cause some symptoms
- Virulence Factors
(a) Animal-specific envelope (e.g. human strains infect humans; avian strains infects avians; swine strains)
(b) Surface antigen changes (e.g. Avian Influenza (H5N1)
(c) Adaptation of virus envelope to enter & replicate in human cell - Antiviral medications available – start treatment within 48 hours to be effective
- Vaccine
(1) Made with the most common 3 antigens
(2) Required annually to match antigenic strains moving toward USA (World Health Org., CDC, and DoD labs track location and movement of strains around the world)
A
- Influenza virus
21
Q
Which virus is the primary cause of the common cold and the most prevalent? How is this virus transmitted and is an RNA or DNA virus?
A
- Rhinovirus
- RNA
- Transmitted by inhalation of droplets and by contact (hands, eyes)
Developing vaccines is challenging.
22
Q
What are the antigenically stable influenza virus types?
A
- Types B & C
23
Q
What are the influenza virus antigenic Type A human subtypes?
A
- H1N1 (swine type adapted to human)
- H3N2
- H5N1, H7N9 (avian subtypes adapted to humans, considered dangerous)
24
Q
Name the etiologic agent that is the second most common agent of colds and second most prevalent? It causes SARs and MERS-CoV. Transmitted by inhalation of droplets and by contact (hands & eyes).
A
- Corona virus
Developing vaccines is challenging.
25
What is SARs?
- SARS (Severe Acute Respiratory Syndrome) (several thousand cases, about 30% mortality)
26
What is MERS-CoV?
- MERS-CoV (Middle East Respiratory Syndrome – Corona Virus) – severe acute respiratory illness (fever, cough, shortness of breath), several hundred persons ill & about 30% mortality since 2012 (mostly Jordan, Saudia Arabia); camels are likely source
27
What virus is aka Human Orthopneumovirus, - the primary agent in infants & young children?
- Respiratory syncytial virus (RSV)
28
Which virus antigenic groups A and B are capable of causing severe infections, immunoglobulins are not necessarily protective against future infections, and developing a vaccine for this virus is very challenging?
- Respiratory syncytial virus (RSV)
29
How is RSV transmitted?
- Transmitted by droplets and contact (especially hands and eyes) and by inhalation of droplets
30
What is croup?
- Croup refers to an infection of the upper airway, which obstructs breathing and causes a characteristic barking cough. The cough and other signs and symptoms of croup are the result of swelling around the voice box (larynx), windpipe (trachea) and bronchial tubes (bronchi).
31
Which virus causes croup, bronchitis, cold-like symptoms; especially frequent in children? Is this virus enveloped and RNA or DNA?
- Parainfluenza virus
| - Enveloped RNA virus - member of Paramyxovirus family; 4 antigenic types
32
What very prevalent RNA virus causes upper and lower respiratory tract illness in later winter and early spring?
- Common cold, bronchiolitis, pneumonia, croup
- Incubation 3-5 days with shedding for few weeks
- Affects all ages; more frequent & more severe in young children
- Human Metapneumovirus (hMPV)
33
What type of adenovirus causes Atypical pneumonia?
-Type 37
34
What types of adenovirus cause acute respiratory disease in military recruits?
- Types 4, 7
35
Which non-enveloped DNA virus is the agent of 5% to 10% of all viral infections (50% of infections before age 5)?
- Adenovirus
Causes:
- acute respiratory disease in military recurits (types 4, 7)
- Conjunctivitis
- Atypical pneumonia (type 37)
- Cold-like disease
- Gastrointestinal disease
- Croup/Bronchitis, sore throat, cystitis
Vaccine available againest types 4 and 7
36
The CMI holds this virus in check, it causes Types 1 & 2 Fever blisters, cold sores, gingivostomatitis, keratoconjunctivitis (neonates, contact lens wearer), genital lesions, meningitis (neonate). The primary lesion is more severe than subsequent, viruses hide (go latent) in nerve ganglia serving the region of the primary lesion.
- Herpes simplex (HSV), DNA, Enveloped
No adequate vaccine
37
What virus causes chickenpox and shingles (latent/recurring), hides in the nerve ganglia, and is held in check by CMI?
- Herpes zoster (HZV)
Vaccines available (chickenpox & shingles)
38
Which DNA enveloped virus is acquired via respiratory tract causing vesicle type skin lesions, moderately large, relatively few, mostly on the trunk of the body?
- Chickenpox: Herpes zoster (HZV)
Vaccines available (chickenpox & shingles)
39
What occurs when HZV remerges from hiding in the nerve ganglia, causing numerous, small, closely- spaced vesicles in the area served by the infected nerve ganglion? Virus outbreak subsides after few-to several weeks but may recur periodically.
- Shingles
Vaccines available (chickenpox & shingles)
40
Name the virus that is transmitted by oral secretions, infects the B-cell, and causes infectious mononucleosis in adolescents and adults.
- Epstien-Barr virus (EBV)
Virus may be eliminated by Cell Mediated Immunity or go into latency
41
What are the symptoms of mononucleosis?
- Fever, sore throat, enlarged lymph nodes, fatigue, swelling of liver or spleen
42
What viruses cause mononucleosis?
- EBV (adolescents and adults)
| - CMV (children)
43
Baby is infected from vaginal microbiota during birthing, occasionally causes mononucleosis with microcephaly, jaundice, multiple organ involvement. Impairment of the central nervous system is associated with the development of mental/physical retardation. Rarely causes obvious illness.
- Cytomegalovirus, CMV (children)
44
Latent virus infection in immunosuppressed / immunocompromised organ transplant, malignancy, AIDS
(a) Febrile mononucleosis
(b) Multiple organ involvement (pneumonitis, hepatitis, GI ulcerations, encephalopathy)
(c) Severity of disease related to competency of cell-mediated immunity
- Cytomegalovirus
45
What virus causes epidemic diarrhea in infants and young children? Transmitted feal to oral transmission and there is a vaccine for it.
- Rotavirus, RNA
46
Which RNA non-enveloped virus causes 90% of epidemic and sporatic viral gastroenteritis? After 18-48 hours of incubation, it causes vomiting, diarrhea, cramps, and low-grade fever. The illness lasts 12-60 hours and often remits spontaneously. Transmitted by food, water, vomitus – very difficult to prevent the spread.
- Norwalk virus
47
Describe the structure of the Human Immunodeficiency Virus.
```
General characteristics (Retrovirus group)
(1) Medium sized, enveloped RNA virus
(2) Structure and composition
(a) Envelope
• Glycoprotein-41 (GP-41)
• Glycoprotein-120 (GP-120)
• Antigenically variable
(b) Capsid: Protein-24 (P-24)
(c) Core
• Two strands of RNA
• Reverse transcriptase -- an enzyme which produces a DNA copy of the genomic RNA (this is an extremely unusual approach)
(3) Two antigenic types: HIV-1 present worldwide and HIV-2 primarily found in Western Africa. (Antigenic variations within each type.)
```
48
Describe the interactions between HIV and Cells.
(1) GP-120 attaches to the CD4 marker on the cell membrane [can infect cells that do not have CD4 markers if they co-infect with another Retrovirus]. GP-41 attaches to a different protein, CXCR4.
(2) The RNA strands enter the host cell
(3) * Reverse transcriptase uses the RNA strands as a template to produce new viral DNA
(4) * The new viral DNA is incorporated into the host cell’s DNA -- remains latent for prolonged period of time
* Unusual characteristic
(5) Alters the ability of CD4 cell to produce cytokines
(6) New virions released from infected cells by budding - ultimately kills CD4 cell
d. Types of cells infected (primary): CD4 Helper T-cells; Monocytes – macrophages
49
How is HIV transmitted?
Transmission of the virus (primarily inside infected cells) [HIV virions have been isolated in all body secretions.]
(1) Intimate sexual contact
(2) Blood and blood products (e.g. transfusion, I.V. drug use, needle sticks, cuts)
(3) Perinatally -- from mother to baby
50
Where are the hot spots of infection for HIV?
- Southern Africa, Southern and Southeastern Asia
51
Describe stage one of the HIV infection.
(1) Stage I -- Primary HIV infection -- lasts about 1 to 4 months
(a) Viruses are replicated and shed at a moderate rate for a short time
• p24 antigen (capsid) may be detectable for about 2-6 weeks after infection
• Antibodies to p24
(b) Symptoms:
• "Mononucleosis-like" or "flu-like" illness. Fever, night sweats, malaise, rash, and muscle and joint pain. Lymphadenopathy may develop.
• Becomes asymptomatic after 1 to 3 weeks
52
Describe the second stage of HIV infection.
(2) Stage II -- Latent (asymptomatic) period
(a) Patients are asymptomatic -- usually lasts few to several years
(b) Viruses are replicated and shed at a low rate
(c) HIV antibodies are detectable
(d) Pathologic characteristics -- Gradual decrease in CD4 cells occurs
53
Describe stage three of the HIV infection.
Stage III -- Persistent Generalized Lymphadenopathy or AIDS Related Complex (ARC)
(a) Virus replication and shedding occurs at a high rate -- p24 antigen becomes elevated again; Antibody to p24 diminishes
(b) Pathologic characteristics -- Gradual reduction of the CD4 cell count.
(c) Symptoms
• Persistent generalized lymphadenopathy (PGL) -- Lymph nodes remain swollen for months with no other signs of infection. Night sweats, weight loss, diarrhea.
• Kaposi's sarcoma
• Opportunistic infections - develop when CD4 cells are less than about 300/ mm3. Oral yeast infections, Recurrent shingles, Bacterial skin infections
54
Describe stage four of the HIV infection.
(4) Stage IV -- AIDS [Acquired Immune Deficiency Syndrome] (symptomatic period)
(a) Pathology
• Significant decrease of CD4 cells (<200/mm3); moderate decrease of CD8 cells
• Antigen to p24 reappears – virus replication overwhelms antibody production
• Antibodies to HIV are ineffective
• Host is gradually unable to mount cell mediated or humoral immunity
(b) Opportunistic infections -- become more severe as CD4 count decreases
• Tuberculosis
• Pneumocystis carinii (protozoan) -- pneumonia
• Fungal infections: Histoplasmosis, Coccidioidomycosis, Cryptococcal meningitis
• Toxoplasmosis gondii (protozoan) -- brain
• Herpes simplex virus, types 1 and 2
• Cryptosporidium -- intestinal
• Cytomegalovirus -- retina, esophagus, colon
• Mycobacterium avium complex -- disseminated
(c) Central Nervous System involvement -- Dementia
55
What virus causes infection of the liver, anorexia, hepatic tenderness, jaundice, and dark urine?
- Hepatitis
56
Are hepatitis viruses taxonomically related to each other?
- No
57
Which DNA enveloped virus has the surface antigen HBsAg and what are the antigens in its core?
- Hepatitis B
- HBcAg (core antigen)
- HBeAg ( associated with high infectivity)
58
What is the earliest marker of acute infection of Hepatitis B?
- HBsAg surface antigen
| Persistence over 6 months implies chronic disease (failure to seroconvert to anti-HBs)
59
How is Hepatitis B transmitted?
(2) Epidemiology & Transmission
(a) Transmission - parenteral route most predominant mode. Contact with blood or blood products, usually via contaminated needles or syringes.
(b) High risk groups
• Intravenous drug users; male homosexuals
• Patients with multiple transfusions; Hemophiliacs; Dialysis
(c) Incubation period
• Usually 45 to 180 days
• Replicates in liver
60
An immune response that is characterized by a conversion from the absence of a specific antibody to the presence of that specific antibody.
- Seroconversion
61
When would you see this immunological marker HBeAg (core-associated “e” antigen)?
* Early indicator of acute infection, active virus replication, and most infectious period
* Persistence beyond 10 weeks indicative of progression to chronic carrier state and probable chronic liver damage
62
When would you see this immunological marker Anti-HBe (antibody to Hepatitis B “e” antigen of the core)?
* Seroconversion from HBeAg to anti-HBe usually occurs during late acute phase - suggests resolution of infection and lowering of transmissibility
* Chronic/carriers fail to seroconvert during acute phase
63
When would you see this immunological marker Anti-HBs (antibody to Hepatitis B surface antigen)?
* Appears during convalescence – indicates recovery and immunity
* Major protective antibody against HBV (also develops from vaccination)
* Failure to seroconvert indicative of chronic infection
64
Which small, lipid enveloped RNA virus is transmitted parenteral route, accounts for 15-40% of community-acquired hepatitis, increases in IV drug users and has a high co-infection with AIDs? No vaccine is available.
- Hepatitis C (HCV)
65
Which virus has the capsid marker HAAg?
- Hepatitis A
66
How is Hepatitis A transmitted?
Epidemiology
(a) Transmission -- fecal-oral route (enteric route) (primarily via food and water)
(b) High-risk groups: Institutionalized persons, Children in daycare centers, World travelers, Military, Drug addicts
67
Which Hepatitis virus replicates in both the liver and small intestine?
- Hepatitis A
68
Causes hemorrhagic fever and renal syndrome?
- Hantavirus
69
This virus is moderately frequent: Northern Asia, Europe and transmitted via inhaled rodent excreta.
- Hantavirus
| Hemorrhagic Fever with Renal Syndrome
70
Which virus is very infrequent in North America, causes pulmonary syndrome and is transmitted via inhaled rodent excreta?
- Hantavirus Pulmonary Syndrome
71
Which virus is frequent in tropical & semi-tropical areas and very infrequent in the USA, transmitted by mosquitoes? Causes fever, severe joint pain (“Breakbone Fever”), conjunctivitis, headache and hemorrhagic fever form (lower frequency) – severe illness.
- Dengue Virus; Dengue hemorrhagic fever
72
Which virus is moderately frequent in tropical Africa, the Amazon basin and is transmitted by mosquitoes?
- Yellow Fever Virus; hemorrhagic fever
73
This virus is moderately Frequent: Africa, SE Asia, South & Central America, transmitted by Mosquitoes and causes Dengue-like symptoms with the hemorrhagic form being rare.
- Chikungunya virus; hemorrhagic fever
74
Name the virus described below:
- Zoonotic in Africa; Infrequent in humans
- Transmitted by mosquitoes
- Rift valley fever virus (RVF); hemorrhagic fever
75
Name the virus described below:
- Infrequent: Africa, Middle East (to West China)
- Transmitted via ticks
- Congo-Crimean Hemorrhagic Fever Virus (CCHF)
76
Name the virus described below:
- Moderately Frequent: West Africa
- Transmitted via rodent excreta (urine)
- Lassa Fever Virus; hemorrhagic fever
77
Which virus causes Hemorrhagic fever that is infrequent West & Central Africa, vectors included fruit bats & bushmeat?
- Ebola Hemorrhagic Fever virus
78
How is Ebola Hemorrhagic Fever virus transmitted?
Fruit bats & bush meat -> animals, human contact
Transmission: Direct contact with blood or body fluids
• At-Risk Areas: mucosal tissue, eyes, breaks in the skin
• Aerosolization may deposit infectious droplets on at-risk tissues, but no aerosol transmission to the respiratory tract
• Superspreaders: 3% of infected persons spread the disease to 60+% of victims
79
Name the virus described below:
Contagious from the day of first symptoms or until no virus is in blood, semen harbors virus up to 3 months
(a) Sudden onset fever, intense weakness, muscle pain, headache, sore throat
(b) Vomiting, diarrhea, rash, internal & external bleeding
(c) Acute fever, Flu-like symptoms, muscle aches, rash/erythema/petechiae
(d) Hemorrhage / Capillary leakage (vascular permeability, abnormal blood clotting) Shock
Causes long-term medical effects in survivors (chronic fatigue, headache, muscle/joint pain, memory loss, eye pain/blurry/sensitivity; hearing loss)
- Ebola Hemorrhagic Fever virus
80
Which encephalitis virus is transmitted by mosquitos and semen with only 20% of infected becoming ill?
- Zika virus
81
Which encephalitis virus is transmitted by tick?
- Tick-Borne EV (TBE)
82
Describe the encephalitis virus disease.
(1) Travels bloodstream to CNS & other organs
(2) Encephalitis (inflammation of the brain) & meningitis (inflammation of the meninges membrane)
(3) Treatment is very limited or non-existent; vaccines usually non-existent
(4) Mortality rate often 20-40%
83
Which encephalitis virus if frequent, geographically effects Africa, India, Middle East, Europe, USA, peaks late summer-early fall and is neuroinvasive?
- West Nile fever virus
84
Which encephalitis virus is infrequent causes fever, rash, joint pain, conjunctivitis, headache, possibly guillain-barre syndrome, and it travels via blood to the fetus causes microcephaly? Effected Africa, Asia, S. pacific, Brazil, and the Americas.
- Zika Virus
85
Which encephalitis viruses are infrequent in North, Central, & South America?
- St Louis & La Crosse
86
Which encephalitis viruses are rare in SE USA, C. America, Northern S. America, and a BTA?
- Eastern/Western/Venezuelan encephalitis viruses
87
Which encephalitis virus is infrequent in Japan, East & SE Asia (China, Korea, India)?
- Japanese encephalitis virus
88
Where is the Tick-Borne encephalitis virus Frequent?
- Eastern and Central Europe
89
Where would I be able to find the rare Murray Valley virus?
- Australia
90
Name the virus described below:
Transmitted by virus-laden saliva of a rabid animal introduced into a bite or scratch (Most prevalent infected animals: coyotes, foxes, skunks, raccoons, bats, cats, dogs – geographical locations vary).
- Rabies virus – genus Lyssavirus, family Rhabdoviridae – RNA virus
91
Name the virus described below:
- Infects brain and affects eye, salivary glands, skin, & other organs
- Encephalomyelitis (almost always fatal once symptoms appear)
- Headache, fever, malaise; a sense of apprehension; spasms of muscles used in swallowing; delirium and convulsions
- Death often due to respiratory paralysis
- Rabies virus – genus Lyssavirus, family Rhabdoviridae – RNA virus
92
Which DNA virus causes various skin warts, sexually transmitted genital warts, possibly cervical and other cancers in males and females?
- Human Papilloma Virus (HPV)
93
Name the viruses described below:
- RNA virus, small, non-enveloped; stable over wide pH and temperature range
- Multiple antigenic types, formerly known as (genus names): Coxsackie, Poliovirus, Echo, & Enterovirus
- Transmission: Fecal to oral, respiratory secretions, contact with vesicle flu
- Enteroviruses
94
Which enterovirus has various antigenic types that cause several diseases (e.g. myocarditis, pleurodynia, vesicular rash)?
- Coxsackie
95
Name the virus described below:
RNA virus
Transmitted person-to-person by contact with respiratory secretions, Highly contagious
Symptoms –cough, rhinitis, high fever, red eyes, macropapular rash (3-5 days after start of symptoms
Secondary complications (30%), esp. diarrhea, blindness, inflammation of brain, pneumonia
Vaccine effective, but many remain unvaccinated
- Measles virus
Symptoms occur about 10-12 days after exposure and last 7-10 days
Contagious from about 4 days prior to 4 days after start of symptoms or rash
96
Name the virus described below:
RNA virus: enveloped single-stranded
Transmitted person-to-person by contact with respiratory secretions, e.g. cough, sneeze, droplets on surfaces
Infection of parotid glands
Symptoms – fever, muscle pain, headache, fatigue, usually followed by swelling of parotid glands (may be confused with swelling of lymph nodes)
Symptoms occur about 16-18 days after exposure and resolve after 4-10 days
Contagious from a few days prior to about 4 days after symptoms
Complications include meningitis, pancreatitis, permanent deafness, testicular/ovarian swelling. Symptoms in adults more severe than in children
Vaccine effective, but many remain unvaccinated
Occasional outbreaks in US (few thousand per year); more frequent in developing countries
- Mumps virus
97
Name the virus described below:
DNA poxvirus
Causes mucous membrane lesions or “water warts” on the skin; most commonly on face, trunk, arms, legs
Transmitted by touching the affected skin
- Molluscum contagiosum virus (MCV)
98
Which virus causes smallpox?
- Variola major virus
99
Name the virus described below:
DNA virus
Synchronous progression: rash – macules, vesicles, pustules, scabs
(a) Begins on face, hands, forearms, and spreads to lower extremities in 7-16 days
(b) Lesions on palms of hands and soles of feet and in mouth
(2) Mortality: 30%
(3) Spread by aerosolized virus in droplets and powdered scabs
(4) Rapidly inactivated by UV light & disinfectants
c. Laboratory diagnosis
(1) Specimens
(a) Vesicles or pustules - Scrape the base of the vesicle or pustule & make a touch prep on a microscope slide.
(b) Scab lesions - Remove as many scabs as possible (place in screw-capped plastic tube)
(2) Diagnostic tests:
(a) Rule out Varicella-Zoster virus – DFA/IFA, and PCR
(b) Variola-specific tests – PCR
- Variola major virus, Smallpox
100
Name the yeast described below:
Yeast
(1) Normal flora of the mouth, throat, large intestine, vagina, skin
(2) Causes mild, opportunistic infections in patients with “mild” metabolic or hormonal disorders (e.g. diabetes, pregnancy, prolonged antibiotic treatment, chronic alcoholism) or those with more extreme moist skin conditions
(3) Can produce life-threatening infections in immunocompromised patients by invading deeper tissues
- Candida albicans
101
Etiological agent of various opportunistic infections -- Overgrowth due to reduction of normal flora resulting from antibiotics, hormones, or metabolic disorders
- Candida albicans
102
What yeast causes Thrush?
White, patchy lesions in the mouth; most common in infants
(a) Pseudomembrane covers the tongue, soft palate, buccal mucosa & other surfaces
(b) Patches of pseudomembrane often crumble & have the appearance of milk curds
- Candida albicans
103
What yeast causes onychomycosis?
- Candida albicans
- Nails become hardened, thickened, brownish and discolored
- Nail plate is striated or grooved
- Mimics tinea unguium or ringworm of the nails caused by dermatophytes
104
What Yeast causes vaginitis in diabetics and pregnant women due to chemical hormone changes?
- Candida albicans
| May resemble thrush
105
Where could you find candida Albicans?
- Cutaneous - found in axilla, groin, mammary folds, interdigital spaces -- may produce inflammation such as diaper rash
106
What about Candida albicans is Systemic – infrequent (almost all in immunocompromised or severely debilitated)?
- Bronchial and pulmonary
- Septicemia
- Meningitis
- Endocarditis
107
Name the yeast described below:
- Emerging serious global health threat (684 cases as of 14 June 2019
- Causes severe invasive infections of blood, heart, brain, eyes, bones
- Often multi-drug resistant
- Difficult to identify with standard laboratory methods, - misidentification leads to inappropriate medication
- It causes outbreaks in healthcare settings. Need to rapidly and accurately identify
- Candida auris
108
Name the Yeast described below:
- Causes severe invasive infections of blood, heart, brain, eyes, bones
- It causes outbreaks in healthcare settings. Need to rapidly and accurately identify
- Candida auris
109
Yeast with thick capsule?
- Cryptococcus neoforms
110
Name the Yeast described below:
- Infection in human is almost always pulmonary following inhalation of this yeast; usually subclinical and transitory; may arise as a complication of other diseases in debilitated patients and become rapidly systemic or even fulminant
- Central nervous system - meningitis -- predilection (affinity) for brain and meninges (more common in AIDS patients
- Cryptococcus neoforms
111
Name the molds described below:
- Dermatophytic molds
- Cause tinea capitis ("ringworm" of scalp), tinea pedis (athlete's foot), tinea corporis, tinea cruis (jock itch), and toenail fungal infection
- Microsporum, Trichophyton, and Epidermophyton
112
Name the mold described below:
Subcutaneous mold: fungal infection involving the skin and subcutaneous tissue, generally without dissemination to the internal organs of the body.
Source - soil, wood, or vegetation -- Usually enters through trauma e.g. rose thorns, wood splinters
c. Clinical presentation
(1) Primary lesion - about three weeks after injury
(a) Begins as a small, non-tender, subcutaneous nodule
(b) Nodule ulcerates causing tissue necrosis and infection of nearby lymph channels
(2) Secondary lesions
(a) Develops multiple subcutaneous nodules along lymph channels; may ulcerate
(b) May spontaneously heal but often become chronic, especially if untreated
- Sporothrix schenckii
NOTE: Sporothrichosis is commonly called "rose gardener's disease". This disease process is an occupational hazard to farmers, nursery workers, florists, forest rangers, and mine workers.
113
Name the systemic mold pathogen described below:
Transmitted via inhalation of spores –often from bird droppings in warm, moist soil
Endemic to Ohio River and Mississippi River valleys; also occurs in Africa & Asia
Clinical disease
(1) Localized lesions in the lungs -- flu-like symptoms (cough, fever) -- ~99% of cases
(2) Organism disseminates throughout the body while inside macrophages
(a) Cell Mediated Immune response is too weak and lesions develop in major organs.
(b) Acute or chronic infection may develop (pneumonia, hepatitis, meningitis) -- usually fatal without treatment
- Histoplasma capsulatum
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Name the systemic mold pathogen:
- Transmitted via inhalation of spores; especially after dust-producing event
- Endemic to semi-arid climate areas of southwestern USA, northern Mexico, and South America -- hot, dry, alkaline soil
- Clinical presentation (San Joaquin Valley Fever, Valley Fever, Desert Fever)
(1) Causes pulmonary lesions and flu-like symptoms -- 99% of cases
(2) Disseminates to other organs (central nervous system, bone, cutaneous) when CMI is weak -- < 1% of cases. High mortality rate.
- Coccidioides immitis
115
Name the pathogen that affects immunocompromised persons, and are found worldwide:
(1) Transmission – inhalation of airborne spores
(2) Clinical presentation - Usually sinus infection, pulmonary/bronchial mass; sometimes invasive causing multi-organ disease
A. fumigatus (and other species)
Aspergillus
116
Produces Aflatoxin when growing in improperly stored (e.g. damp) nuts, grains, seeds, and other foods
(1) Transmitted by the ingestion of toxin
(2) Clinical presentation – liver damage, often severe
- A. flavus
Aspergillus
117
Name the mold that causes pneumonia in immunocompromised persons, e.g. cancer, chemotherapy, HIV/AIDS – low frequency
(1) Attacks interstitial, fibrous tissue of the lungs leading to significant hypoxia
(2) Non-productive cough, shortness of breath, night sweats, fever
(3) Risk increases when CD4 cells are less than 200 cells/uL (immunocompromised
- Pneumocystis jirovecii pneumonia (PCP)
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One of the less common molds that may grow inside buildings where moisture is present; and may produce mycotoxins and pose an increased risk of allergy and asthma.
b. “In 2004 the Institute of Medicine (IOM) found there was sufficient evidence to link indoor exposure to mold with upper respiratory tract symptoms, cough, and wheeze in otherwise healthy people; with asthma symptoms in people with asthma; and with hypersensitivity pneumonitis in individuals susceptible to that immune-mediated condition. The IOM also found limited or suggestive evidence linking indoor mold exposure and respiratory illness in otherwise healthy children.” (CDC Web site)
c. CDC recommends a common-sense approach to prevent and remove mold growth in the home.
- Stachybotrys chartarum
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List of Respiratory viruses:
- Corona virus (SARS, MERS-CoV)
- RSV
- Parainfluenza virus (croup, bronchitis)
- hMPV (bronchiolitis, croup, pneumonia)
- Adenovirus (Acute Respiratory Disease, Atypical pneumonia, croup, bronchitis)
120
List of skin wart or nodule producing diseases.
- HPV (skin and genital warts)
- Molluscum contagiosum virus, mucous membrane lesions (water warts)
- Sporothrix schenckii mold (lesion, subcutaneous nodules)
- Herpes simplex (genital lesions)
121
Common disease causes in children.
- RSV
- Parainfluenza virus
- hMPV (more severe in young children)
- Cytomegalovirus (CMV)
- Rotavirus (diarrhea in infants and young children)
- Hepatitis A (children in daycares fecal to oral route)
122
Fungi that produce toxin.
- Stachybotrys chartarum (mycotoxins)
| - A. flavus (aflatoxin)
123
List of GN bacteria mentioned.
- Burkholdria (GNB)
| - Fusobacterium (GNB)
124
List of GP bacteria.
- Peptostreptococus (GPC, chains)
- Bifidobacterium (GPB)
- Faecalibacterium (GPB)
125
List of NSF bacteria mentioned.
- Faecalibacterium
| - Bifidobacterium
126
List of Anaerobic bacteria.
- Bifidobacterium
- Faecalibacterium
- Fusobacterium
- Peptostreptococus
127
List of spirochetes.
- Treponema pallidum
- Borrelia burgdorferi
- Leptospira interrogans
128
Two organisms of different species living together
- Symbiosis
129
Symbiotic relationship in which one organism is benefited and the other is neither benefited nor harmed
- Commensalism
130
Symbiotic relationship in which both organisms are benefited
- Mutualism
131
Symbiotic relationship in which one organism, the parasite, is metabolically dependent on the other organism (host) and gains all the benefit. The host is adversely affected.
- Parasitism
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Normally free living organism, but may become an opportunistic parasite
- Facultative parasite
133
Cannot survive in a free-living state
- Obligate parasite
134
Establishes itself in a host in which it does not normally live.
- Incidental parasite
135
A parasite living inside the host
- Endoparasite
136
A parasite living on the external
| surface of the host
- Ectoparasite
137
Any living organism, animal or plant that harbors or nourishes another organism
- Host
138
The host that harbors the adult or sexually reproducing stages of a parasite
- Definitive host
139
That host which harbors the immature, larval, or asexually reproducing forms of a parasite
- Intermediate host
140
A host which replaces man in the life cycle of the parasite
- Reservoir host
141
A host that serves as a transport host in which the parasitic forms undergo no development, but passes on to the final host
- Paratenic host
142
The process of a parasite’s growth, development and reproduction, which proceeds in one or more different host depending on the species of parasites.
- Life cycle
143
A stage when a parasite can invade a human body and live in it.
- Infective stage
144
The entrance in which the parasite invades the human body.
- Infective route
145
How the parasite invades the human body.
- Infective mode
146
A carrier, usually an arthropod, which transmits an infective form of the parasite from host to another
- Vector
147
A reinfection in which the host is its own source of infection from a source already present in the body
- Autoinfection
148
Through host tissues, skin or mucous membranes
(a) Remains on or within the epidermis or subcutaneous tissues
(b) Penetrates to other host organs or tissues
- Active penetration route of infection
149
Oral (nasopharyngeal) in food, water or aerosols, etc.
(a) Remains in gastrointestinal tract
(b) Internal migration to other host organs or systems
(c) Migration through other host systems and return to gastrointestinal sites
- Ingestion route of infection
150
Through host tissues by vector or agent
(a) Arthropod-borne: By mouth parts, salivary glands, or waste products
(b) Transfusion: Present in donor blood at time of transfusion
- Injection route of infection
151
Transmission of parasites across the placental barrier from mother to fetus
- Congenital route of infection
152
Forms of Parasites Studied:
1. Adult
2. Larva
3. Egg/Ova
4. Trophozoite
5. Cysts
153
Liquid and diarrheic specimens: Should be examined within _____ from time of passage (type of specimen where trophozoites may be found)
- 30 minutes
154
Formed specimens: Can be delayed for _____ or longer, but should be examined on the same day of submission
- several hours
155
What test is described below?
Used to detect parasites, protozoa and helminths, in the upper part if the small intestine
Do not eat 12 hours prior to testing
The end of the string is taped to your cheek or neck
A capsule containing the remainder of the string is swallowed
The capsule will dissolve and move into your stomach were the string will unravel
Usually the patient relaxes for about four hours
The string gathers materials from the stomach and upper intestines
After the allotted time, the string will be pulled back up through the throat, placed in a container and sent to the lab
Remove mucous from string and examine by wet mount technique
- Enterotest - String test
