Micro E3 pt 2

Which DNA viruses are single- stranded?

Parvoviruses

Which RNA viruses are double-stranded?

Reoviruses

What three criteria divide human viruses into families?

Type of nucleic acid they carry, type of capsid, presence of an envelope

What effect on the host cells account for the pathology and loss of function associated with viral infections?

Lytic effect destroys them

Name the 2 types of persistent viral infections.

Chronic and latent

Define a chronic viral infection.

Virus is detectable in tissues samples, multiplying at a slow rate; Sx are mild or absent Ex: HIV, HBV, HCV

Define a latent viral infection.

After a lytic cyle, the virus enters a dormant pahse inside the host cells remaining inactive and typically undetectable, but can reactivate and result in recurrent infections Ex: HSV, VZV

What cancer is associated with human papillomavirus?

Cervical and penile cancer

What cancer is associated with hepatitis B & C?

Hepatic carcinoma

What cancer is associated with human herpesvirus 8?

Kaposi sarcoma

When did routine vaccination end for Smallpox?

1972

Why was the Smallpox vaccine reintroduced in 2002?

Prevent bioterrorism

What virus causes Smallpox?

Variola

Describe the clinical presentation of molluscum contagiosum.

Flesh-colored, smooth, waxy, dome-shaped papules/nodules w a central umbilication or indentation; axillae and trunk commonly affected

What is the most common patient population this molluscipoxvirus is seen in?

Children

How is Molluscum contagiosum transmitted?

Skin-to skin contact and fomites

How many viruses make up the Herpes virus family?

8 (HSV-1, HSV-2, VZV, CMV, EBV, HHV-6, HHV-7, HHV-8)

What disease is associated with HHV-6 and HHV-7?

Roseola

Why do all members of the Herpes viruses show latency and cause recurrent infection?

After entry of the viral DNA into the nucleus of the host cell, it becomes an extrachromosomal particle

Describe the primary infection of HSV1 including the location and typical patient population.

Lesions on the oropharynx (can by optic); typically occurs in early childhood – early adulthood

Describe the primary infection of HSV2 including the location and typical patient population.

Lesions on the genitalia; primary infection often occurs in ages 14-29

What is the typical transmission of HSV1 and HSV2?

Direct exposure to secretions containing the virus

Name three different medications used to treat the HSV and how soon treatment should begin.

Acyclovir, famicyclovir, valacyclovir; treat w/in 72 hours of Sx onset

Which nerve ganglia do the HSV1 and HSV2 virus enter?

HSV1 enter 5^th cranial nerve; HSV2 enters lumbosacral spinal nerve

Provide a brief review of Herpes in the newborn.

Spread during or before birth if lesions are present; Potentially fatal, can infect the CNS; C-secition may help prevent this

Describe the classic pattern of the HSV infection in a premature infant.

Cigarette burn lesions

Describe the clinical presentation of herpetic whitlow and the most common patient population you would see this in.

Usually a location infection on one finger, may become inflamed and necrotic; seen in healthcare workers in OB/GYN, dentristry, and respiratory therapy

If a patient has HSV, what would you see on a Tzanck smear?

Multinucleate cells, giant cells, and inclusion bodies w/in the nucleus

Name the 2 diseases caused by VZV and the mode of transmission.

Chicken pox and Shingles; spread via respiratory droplets and contact w/ fluid from lesions

What does VZV stand for?

Varicella-Zoster Virus

Describe the typical presentation of chicken pox.

Fever, rash, macules -> itchy vesicles that encrust and drop off, all over the body, “dew drops on a rose petal”; more common in children

Describe the typical presentation of shingles.

Vesicles localized to distinctive dermatomes, often preceded by pain; more common in pts over 60

What 2 complications can VZV cause?

Post-herpetic neuralgia and Zoster opthalmicus (EMERGENT)

What is the typical presentation of a cell infected with CMV.

Giant cells, distortion of nucleus, “owl’s eye”

What virus causes infectious mononucleosis and what is the mode of transmission?

Epstein-Barr (EBV); direct oral contact and contamination with saliva, blood transfusion, organ transplant

Describe the typical presentation of mononucleosis.

Sore throat w/ gray-white exudate, high fever, LAD, splenomegaly

What 2 cancers are associated with Epstein-Barr virus?

Burkitt’s lymphoma and Nasopharyngeal carcinoma

 Describe the pediatric presentation of Roseola infantum.

Fever followed by a pink maculopapular rash on trunk and extremities

What virus is associated with Roseola infantum?

Human Herpes Virus 6 (HHV-6) (B-lymphotropic virus)

What is the most common malignant tumor in AIDs patients and what virus is it associated with?

Kaposi sarcoma: HHV-8

Which Hepatitis virus is a DNA virus? What organ is primarily involved?

Hepatitis B virus (HBV); liver

How is HBV transmitted?

Small amounts of blood, blood products, sexually transmitted

Describe the common clinical features associated with HBV.

Mild sx, malaise, fever, chills, anorexia, abd discomfort, diarrhea; severe: jaundice, rash, glomerulonephritis

Standard screening for HBV occurs in which situations?

Blood for transfusion, semen for sperm banks, organs for transplant, routine prental testing of all pregnant women

What is the primary prevention of HBV?

Vaccination

What is a condyloma acuminata?

Skin-colored or pink lesions, range from smooth, flattened appules to verrucous papilliform; most common STI

What is a condyloma lata?

Skin-colored, moist lesions, vary is size and appearance

What lesion is associated with secondary syphilis?

Condyloma lata lesions

Which HPV types are most commonly isolated in patients with cervical cancer?

HPV 16 and HPV 18

What vaccine can protect an individual from HPV?

Gardasil 9

What virus causes erythema infectiosum?

Parvovirus B19

What is another name for erythema infectiosum?

Fifth disease

Describe the clinical presentation of Fifth disease.

Low-grade fever followed by a rash, “slapped face” appearance, lacy, maculopapular rash

What months do we usually experience epidemics of influenza?

November – April

Which influenza type is the most virulent?

Type A due to antigenic shift

What is the primary mode of transmission of influenza?

Inhalation of aerosols and droplets

What is the most common complication experienced after being infected with the influenza virus?

Secondary bacterial pneumonias

Name the two influenza glycoproteins discussed in class and their action.

Hemagglutinin: binds to host Neuraminidase: hyrolyzes respiratory mucus and assists viral budding and release

Define antigenic drift.

Gradual minor antigenic change w/in the H or N that decreases ability of host memory cells to recognize them; responsible for epidemics

Define antigenic shift.

Major antigenic change w/in H or N resulting in a new subtype, one gene is substituted w/ a gene from another flu virus; responsible for pandemics

Name the neuraminidase inhibitors used to treat influenza and how soon they should be initiated after developing influenza symptoms.

Zanamivir, Oseltamivir, Peramivir; w/in 24-30 hrs, no benefit if >48hrs

Name 4 arenavirus diseases.

Lassa fever, Argentine hemorrhagic fever, Bolivian hemorrhagic fever, Lymphocytic choriomeningitis

What are the sydromes associated with the American bunyavirus?

Hantavirus pulmonary syndrome (HPS) and Hemorrhagic fever w/ renal syndrome (HFRS)

Paramyxoviruses have glycoprotein spikes and fusion spikes. What do the fusion spikes initiate and how does this increase the virulence?

Initate the fusion of infected cells w/ neighboring cells -> syncytium or multinucleate giant cells; allows virus to pass undetected from infected cells to non-infected cells

Croup is a pediatric illness caused by the parainfluenza virus. Describe the typical clinical presentation of a child with croup.

Inspiratory stridor, tachypnea, barking seal-like cough, inflamed and narrow airway, hypoxemia

What medication can be prescribed to lessen the symptoms of croup?

Dexamethasone

Describe the typical presentation of a patient with mumps.

Fever, painful swelling of one or more salivary glands (typically parotid), usually bilaterally, malaise, HA, muscle pain

What are the most common complications of the mumps?

Orchitis, epididymitis, oophoritis, aseptic menigitis, pancreatitis

How can mumps be prevented?

MMR vaccine

Measles (Rubeloa) is caused by a morbillivirus. What is another name for this infection?

Red Measles

 How is Rubeola transmitted?

Via respiratory droplets

Describe the rash associated with Rubeola.

Erythematous, maculopapular, blotchy rash appears first on the head -> trunk and extremities; spares palms and soles

What clinical finding of Rubeola is pathognomonic?

Koplik’s spots: Whitish, grayish, bluish small elevations w/ an erythatous base, typically on buccal mucosa; present 48hrs prior to the rash

How many vaccinations are needed to obtain 95% ser-conversion?

Usually 2

What is the most serious complication of Rubeola?

Subacute sclerosing panencephalitis; presents 7-10 yrs after infection

What causes RSV?

Pneumovirus

RSV typically presents in what population?

Children < 6 mo

When is the peak seasonal outbreak of RSV?

Winter and early spring

Describe the clinical presentation and symtpoms of RSV.

Fever, rhinitis, pharyngitis -> cough, wheezing, tachypnea, dyspnea

What infection does the Rhabdovirus cause?

Rabies

What are the three phases of Rhabdovirus?

Prodromal, Furious, Dumb

What S/sx are associated with the Prodromal phase of a Rabies infection.

Fever, nausea, vomiting, HA, fatigue; some pain, burning, paraesthesias at wound site

What S/sx are associated with the Furious phase of a Rabies infection.

Agitation, disorientation, seizures, twitching, spasmas in the neck and pharyngeal muscles upon swallowing, hydrophobia

What S/sx are associated with the Dumb phase of a Rabies infection.

Paralyzed, disoriented, stuporous, coma, death

Name the most common Rhabdovirus reservoirs in the US.

Bats, raccoons, skunks, foxes

What is the post- exposure prophylaxis of rabies?

Human rabies immune globin (HRIG) or vaccinations w/ human diploid cell vaccin or purified chick embryo cell vaccine

What finding during autopsy is diagnostic of rabies?

Negri bodies -collections of virions in the cytoplasm of brain cells

The Filovirus, Ebola, is one of the most virulent human pathogens that can cause severe hemorrhagic disease. Describe the progress of the disease.

Incubation 2-21 days -> nospecific sx: fever, chills, malaise -> severe diarrhea, nausea, vomiting, uveitis -> nonpruritc rash, can desquamate -> meningoencephalitis, bleeding

What is the mode of transmission of Ebola?

Person-to-person via direct contact of broken skin or unprotected mucous membranes w/ virus containing body fluids

What is the treatment for Ebola?

Inmazeb for the Zaire species; supportive care

What is the mode of transmission of MERS?

Via aerosols and droplets

What are the clinical symptoms of MERS?

Acute respiratory sx, fever, cough, SOB, sore throat, hemoptysis, myalgias, diarrhea, vomiting, abdominal pain, abn CXR; can leads to pneumona and ARDS

What is the treatment for MERS?

Supportive care

List two other names for Rubella.

Three-day measles, third exanthematous disease of childhood, German measles

What is the mode of transmission of Rubella?

Inhalation of droplets

Why is it important for pregnant women to be vaccinated for Rubella? List the possible pregnancy complications.

Can pass to the fetus: infection, intra-uterine death, spontaneous AB, congential Rubella Syndrome (malformation of major organ systems)

Describe the possible clinical presentation of an individual with Rubella.

HA, low fever, malaise, LAD, rash (fine, pink, maculopapular states on face) conjunctivitis, Forcheimer spots (on the soft palate)

What class of medications are used to treat Hepatitis C?

Direct acting antivirals (DAAs)

What is an arbovirus?

Virus that is spread by arthropod vectors (mosquitoes, ticks, flies, gnats)

List the encephalitis-causing diseases associated with ticks.

Colorado tick fever