Onfectious Disease Part 2 Flashcards by joseph dizon

Transient infections

Measles
Mumps
Polio virus
West Nile virus
Viral hemorrhagic fever

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Is a leading cause of vaccine preventable death and illness worldwide

Measles or rubeola virus

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Measles is transmitted by

Respiratory droplets

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Transient infections

Measles
Cell surface receptors for the virus

All nucleated cells

CD46

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Transient infections

Measles
Cell surface receptors for the virus

Cells of immune system

SLAM or

CD150

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Transient infections

Measles
Cell surface receptors for the virus

Epithelial cells

Nectin 4

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Measles pathogenesis

Both CD46 and SLAM bind the

Viral hemagglutinin protein

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Measles pathogenesis

Viral entry
Multiply in upper respiratory epithelial
Lymphoid tissues
Replicate. In lymphatics
Blood and systemic dissemination

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Measles dissemination to many tissues

Conjunctiva
Respiratory tract
Urinary tract
Small blood vessels
Lymphatic system
CNS

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Measles with T cell mediated immunity

Rash

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Measles with malnourished children

Croup
Pneumonia
Diarrhea
Keratitis

Black measles

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Measles with Ab mediated immunity

Protects against reinfection

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Measles can cause transient but profound immuno suppression

Secondary bacterial and viral infection

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Measles

Vasodilation of skin vessels, edema, and moderate non specific mononuclear peri vascular infiltrate

Blotchy, reddish brown RASH

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Measles

Ulcerated mucosal lesions in oral cavity near opening of stensen ducts marked by necrosis, neutrophils exudate and neurovascularization

Koplik spots

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Measles

Follicular hyperplasia of lymphoid organs with multinucleated giant cells

Warthin- finkeldey cells

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Measles

Peri bronchial and intestinal mononuclear cell infiltration

Measles pneumonia

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Mumps

Characteristics

Mumps virus a member of paramyxovirus just like measles

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Mumps

Two types of surface glycoproteins

Hemagglutinin and neuramidase activity

Cell fushion and hemolytic activity

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Mumps

Pathogenesis

Inhalation of respiratory droplets
URT
Draining lymphnodes
Activated T cells
Blood
Salivary glands and other sites (CNS, testis,ovary and pancreas)

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Mumps

Desquamate on of cells, edema, and inflammation

Infects salivary gland ductal epithelial cells

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Mumps

Most common extra salivary gland complication

Aseptic meningitis

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Mumps

70% bilateral
Salivary glands are enlarged with doughy consistency, moist, glistening and reddish brown on cross section

Memos parotitis

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Mumps parotitis

Microscopic

Edematous gland interstitium
Diffuses infiltration by macrophages, lymphocytes and plasma cells
Compress acini and ducts

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Mumps Testicular swelling due to edema, mononuclear cell infiltration, and focal hemorrhages

Mumps orchid is

Mumps or hits pathogenesis

Parenchymal swelling Compromise blood supply Positive areas of infarction

Mumps Sterility due to

Scars and atrophy of the testis after resolution of infection

Mumps Parenchymal and fat necrosis with neutrophil rich inflammation

Pancreas

Mumps Peri venous demyelination and perivascular mononuclear cuffing

Mumps encephalitis

A spherical, unencapsulated RNA virus of the entero virus genus

Poliovirus

Poliovirus There are 3 major strains of polio virus included in the

Stalk formalin-fixed (killed) vaccine | Sabin oral, attenuated (live) vaccine

Poliovirus Causes poliomyelitis or inflammation of gray spinal cord also known as

Infantile paralysis

Poliovirus Pathogenesis

``` Fecal oral route Oropharynx Secreted in saliva Swallowed Multiply in lining of mucosa Viremimotor neuron of spinal cord or brain stem ```

Poliovirus Species specificity determined by amino acid residues that are present in the

Human receptor CD 155 Epithelial adhesion molecule

Poliovirus Replicates in

``` Motor neurons of the spinal cord (spinal poliomyelitis) Brain stem ( bulbar poliomyelitis) ```

Poliovirus Rare cases of poliomyelitis that occur after vaccination are caused by

Mutations of the attenuated viruses to wild type forms

Poliovirus Microscopic

Neuronophagia

West Nile virus

Arthropod borne virus (arbovirus) of the flavivirus froup

West Nile virus Accidental host

Human

West Nile virus Transmission

Mosquitoes to bird or mammals | Developed prolonged viremia (major reservoir for the virus)

West Nile virus Pathogenesis

``` Mosquito bites Dendritic cells Lymphnodes Blood stream BBB Infects neurons ```

West Nile virus Essential host factor that resist neuro invasive infection

Chemokine receptor CCR5

West Nile virus Associated with symptomatic and lethal WNV infection (protective against HIV-1 infection

CCR5 32 allele

West Nile virus Microscopic

Encephalitis

Viral hemorrhagic fevers Systemic infectious caused by enveloped RNA viruses in four different genera

Arenaviridae Filoviridae Bunyaviridae Flaviviridae

Viral hemorrhagic fevers Hemorrhagic manifestations due to

Thombocytopenia or severe platelet or endothelial dysfunction

Viral hemorrhagic fevers Increased vascular permeability

Necrosis and hemorrhage in organs, | hepatocellular necrosis

Viral hemorrhagic fevers Infection stimulates cytokine release

Contribute to severe cytophatic effects or DIC

Chronic latent infections (herpesvirus infections)

Herpes simplex virus Varicella zoster virus Cytomegalovirus

Chronic latent infections The persistence of viral genomes in cells that do not produce infectious virus

Latency

Herpes viruses

Large Encapsulated Ds DNA genome

Non infectious form with periodic reactivation and shedding of infectious virus

Herpes virus

Three subgroups of herpesviruses Alpha group viruses

Herpes simplex virus 1&2 | Varicella zoster virus

Three subgroups of herpesviruses Lhymphotropic beta group viruses

CMV or HHV5 HHV6 HHV7

Three subgroups of herpesviruses Infect and produce latent infection in a variety of cell types

Lymphotropic beta group viruses

Three subgroups of herpesviruses Gamma group viruses

EBV | HHV-8/KSHV (karposi sarcoma)

Three subgroups of herpesviruses Latent infection mainly in lymphoid cells

Gamma group viruses

Produce acute and latent infection | Replicate in skin and mucous membranes at the site of entrance of the virus (Oropharynx or genitals)

HSV 1 and 2

HSV 2 infection increases the risk of HIV transmission by

Four fold

HSV2 increases the risk of HIV acquisition by

Two to three fold

HSV2

Negative keratitis Negative encephalitis in adult 70%neonatal infection Transmission is primarily genital

HSV1

``` Urogenital infections 10-30% Positive kaperatitis Positive encephalitis adult Neonatal infection 30% Transmission primarily non genital ```

HSV infected cells contain large, pink to purple intranuclear inclusions

Cowdry type A

Herpes simplex virus Due to ballooning degeneration of epidermal cells and intracellular edema

Fever blisters | Cold sores

Herpes simplex virus HSV1 Seen in children Vesicles extending to retro pharynx with cervical LAD

Gingivostomatitis

Herpes simplex virus HSV1 Swollen, erythematous lesions of the fingers or palm Infant and health care workers

Herpetic whitlow

Herpes simplex virus HSV1 and HSV2 Vesicles on the genital mucous membranes and external genitalia rapidly converted to superficial ulcerations Can be transmitted to neonates during passage of birth canal

Genital herpes

Herpes simplex virus Temporal lobes are the principle target Hemorrhagic necrosis

Herpes encephalitis

Herpes simplex virus Diagnisis

Tzanck smear

Herpes simplex virus Diagnosis Rapid result but cannot distinguish between HSV and VZV

Electron microscopy of vesicle fluid

Herpes simplex virus Diagnosis Can distinguish between HSV andVZV

Immunofluorescnence of skin scrapping

Herpes simplex virus Diagnosis Now used routinely for the diagnosis of herpes simple encephalitis

PCR

Herpes simplex virus Diagnosis HSV1&2 are among the easiest to cultivate. It usually takes only 1-5 days for a result to be available

Virus isolation

Herpes simplex virus Diagnosis Used to document the recent infection. Not useful in acute phase

Serology

Varicella-Zoster Virus Acute infection

Chickenpox

Varicella-Zoster Virus Reactivation of latent

Shingles(herpes zoster)

Varicella-Zoster Virus Spread by

Respiratory aerosols

Varicella-Zoster Virus Like HSV

Infects mucous membrane | Evades immune response and establishes latency in sensory ganglia

Varicella-Zoster Virus Unlike HSV

Aerosols Hematogenously Widespread vascular lesions

Varicella-Zoster Virus Chickenpox Rash occurs approximately

2 weeks after respiratory infection

Varicella-Zoster Virus Chickenpox Lesions

Multiple Centrifugally Dew drop on a rose petal like HSV

Varicella-Zoster Virus Shingles Occurs when

Latent VZV in the dorsal root ganglia is reactivated and infects sensory nerves that carry it to one or more dermatomes

Varicella-Zoster Virus Shingles Lesions

Intense itching Burning Sharp pain Because of radiculoneuritis

Varicella-Zoster Virus Shingles Geniculate nucleus may be involved causing facial paralysis

Ramsay hunt syndrome

Cytomegalovirus Latently infects monocytes and their BM progenitors and can be reactivate when

Cellular immunity is depressed

Cytomegalovirus Cause asymptomatic or mononucleosis like infection in healthy individual but

Devastating in neonates and immunocompromised patients

Cytomegalovirus Virus is spread in most secretions, particularly

Saliva Urine Vaginal secretions Semen

Cytomegalovirus Most common opportunistic viral pathogen in

AIDS

Cytomegalovirus Modes of transmission

Transplacental Neonatal transmission via cervical or vaginal Transmission via saliva Latrogenic transmission

Cytomegalovirus Can infect dendritic cells and impair antigen processing and the ability of dendritic cells to stimulate

T lymphocytes

Cytomegalovirus Eludes immune response by

Down modulating MHC 1&2 Producing homologous of TNF receptor Activate and evade NK cells

Cytomegalovirus Produce enlargement of infected cells

Cytomegaly

Cytomegalovirus Large inclusion body within the nucleus surrounded by clear hale

Owl's eye

Cytomegalovirus Cytomegalic inclusion disease

Congenital infections

Cytomegalovirus Infection acquired during passage through the birth canal or from breast milk

Perinatal infection

Cytomegalovirus Fever, atypical lymphocytes Lymphadenopathy Hepatitis

Cytomegalovirus mononucleosis

Hepatitis B virus Member of the

Hepadnavirus family

Hepatitis B virus A DNA virus transmitted percutaneously

Sexually | Perinatally

Hepatitis B virus A etiologic agent of

Serum hepatitis

Includes viruses implicated in the causation of human cancer

EBV HOV HBVC HTLV1

Epstein Barr virus Also known as

Human herpes virus 4 | Member of herpes virus family

Epstein Barr virus Transmitted by

Close human contact, frequently with saliva during kissing

Epstein Barr virus Benign, appearance of atypical T lymphocytes in blood (mononucleosis cells)

Infectious mononucleosis

Epstein Barr virus Associated with developmant of

Hairy leukoplakia Burkitt lymphoma Nasopharyngeal carcinoma

Epstein Barr virus Infects cell types that express the receptor for complement C3d component_______ certain _______ and ________

CR2 CD21 Epithelial cells B lymphocytes

Epstein Barr virus Binds EB genome to host cell chromosome

EBNA1

Epstein Barr virus Drives B cell activation and proliferation

LMP1

Epstein Barr virus Promotes B cell activation and replication

EBNA2

Epstein Barr virus Inhibits macrophages and DCs and suppress antiviral T cell responses

Produce homologue of IL-10

Epstein Barr virus Pathogenesis Activated B cells disseminate in the circulation secrete antibodies with several specificities

Heterophile anti sheep red blood cell

Epstein Barr virus Atypical lymphocytes

CD8 + CTLs and | CD16 + natural killer cells

Epstein Barr virus Reactive proliferation of T cells largely centered in lymphoid tissues

LAD | Splenomegaly

Epstein Barr virus Diagnosis depends on

Lymphocytosis Monospot test ( + heterophile antibody) Specific antibodies for EB antigens

Four types of viral infection

Acute or transient infections Chronic latent infections Chronic productive infections Transforming infections

Onfectious Disease Part 2 Flashcards

(114 cards)