Resp Virus, Childhood Viruses, HPV And Gastroenteritis Flashcards
Describe Influenza
Single stranded RNA virus, ENVELOPED, SEGMENTED GENOME
Actually 3 viruses
How is influenza spread
RESPIRATORY DROPLETS ON SOILED HANDS
Why is influenza A more important?
Pandemic potential and usually more severe
Describe Influenza A
Humans AND animals infected
Outbreaks, epidemics and pandemics
Yearly antigen DRIFT
Liable for antigenic SHIFT
Describe influenza B
Usually less severe Humans only Outbreaks and epidemics Yearly antigenic drift Not liable to shift
What js the difference between colds and flu
Cold: gradual (slow) onset, little or no fever, coryza; no vaccine or treatment
Flu: rapid onset, fever, fatigue; vaccine and treatment available
What proteins are present on the surface of the influenza virus
HEMAGGLUTININ (the H in H1N1) which attaches to cell receptors
NEURAMINIDASE (N in H1N1) which frees the virus to infect other cells
What are drifts
Small changes or mutations are called drifts, these are present in both influenza A&B
Drifted viruses contribute to epidemics and deaths in vulnerable
What are shifts
Larger changes or mutations only present jn influenza A
Shifted viruses cause pandemics
Shifts are reassortments of avian and human viruses; new viruses emerge
Describe how a shift occurs
Pigs!
Pigs have receptors for both avian and human strains of influenza, pig acts as mixing vessel and shifts segments to pop out a new virus
What are potential complications of influenza
Lower respirstory tract (direct viral effect): croup, bronchiolitis(kids), primary pneumonia
Secondary bacterial infection:
Pneumonia or otitis media
And heart failure
Describe seasonal influenza vaccine
Quadrivalent- 2 type A and 2 type B
60-80% effective in healthy young adults
20-30% effective in elderly
50-60% effective in preventing hospitalization
How is influenza treated
Neuraminidase inhibitors
Osteltamivir (tami flu) h1n1 resistant
Zamamivir (inhaler) not convinient
MUST BE TREATED within 72 HOURS preferably 24 hours post infection for it to be effective
Describe respiratory syncytial virus (RSV)
A paramyxovirus
Most common cause of bronchiolitis in children
Manifests as common cold in older kids and adults
Almost all kids infected by age 4; maybbe fatal if heart and lung disease
How is RSV transmitted
Hand contact and respirstory route occasionally
How is RSV treated?
Ribavirin, requires hospitalization and is reserved for severe infection
Describe parainfluenza viruses
Pretty common; bad cold with persistent cough? Probably parainfluenza
Infection limited to nasopharynx
Approximately 2% get croup
Describe rhinovirus
A picornavirus positive strand RNA virus
Infects upper airway (common cold, sinitus, sore ear)
How are respiratory viral infections diagnosed?
Symptoms Time of year Whats in community Virus antigen detection (not rhinovirus) Molecular methods (pcr)
Describe measles
Paramyxovirus (related to mumps and rsv)
World wide occurence
Vaccine available
How is measles transmitted
AIRBORNE
After initial replication it disseminates (viremia)
What are symptoms of measles
Takes 2 weeks for rash to develop
Maculopapular rash evolves from face to trunk to extremities INCLUDING PALMS AND SOLES
FEVER AND 3 Cs: cough coryza and conjunctivitis
KOPLIK SPOTS (sugary spots near molar teeth)
What are some complications of measles
Thousands of 3rd workd kids die yearly Otitis media Pneumonia Encephalitis Death
When is measles communicative
Communicable 4 days before and 4 dats after development of rash
How is measles diagnosed
Not easy to diagnose IgM antibody levels the best option
Describe the measles vaccine
A live vaccine administered with mumps and rubella as MMR or with mumps and rubella and varicella as MMRV
Given in 2 doses now
Describe rubella
RNA togavirus
Spread by respiratory droplets or vertically (mum to baby)
Rash develops after 2-3 weeks
May be infected and not know esp young kids
What are some symptoms of rubella
Rash
Adenopathy (swollen lymph nodes)
Adults may get mild arthritis
What are some complications of rubella
Congenital rubella most severe: Cardiac abnormalities Cataracts Deafness Brain, liver, organ damage
How is rubella diagnosed
IgM antibodies
Describe erythema infectiosum
Fifth disease
Caused by PARVOVIRUS B19 INFECTION
Worldwide, common in early childhood
How is fifth disease transmitted
Respiratory droplets
Vertical (biggest worry)
What are complications of fifth disease
Slapped cheek rash sparing mouth
Lacy pink rash in extremities
May cause miscarriage or fetal abnormalities
How is fifth disease disgnosed
Antibody detection (IgM) No vaccine
Describe Mumps
A paramyxovirus
Worldwide
Uncommon thanks to vaccine
Incubation period 2-3 weeks
How is mumps spread
Droplets and fomites contaminated by saliva
What are some complications of mumps
Parotid gland swelling (95%)
Orchitis (young men may cause sterility)
Meningitis (15%)
Encephalitis and pancreatitis
How is mumps diagnosed
Looking for viral RNA in saliva or urine (PCR)
Describe chicken pox
A member of herpes viridae family
Very very infectious
Unlike other herpes virus almost all infections are symptomatic
How is chicken pox transmitted
Airborne
How is chicken pox characterized
Fever, generalized vesicular erruption
What js the incubation period of chickenpox
11-13 days
Virus replicates in throat and spreads during secondary viremia to skin, tissue, rarely to lungs and brain
What is the typical progression of chicken pox
Macule -> papule -> vesicle -> pustule -> ulcer -> crust
What are complications of chicken pox
Pneumonia (very serious)
Disseminated infections in immuno compromised
Severe infections in newborns
CNS involvement (rare)
Bacterial superinfection from kids scratching or picking (S.Aureus/S.Pyrogenes)
How is varicella zoster infections (shingles/chickenpox) diagnosed
Clinical syndrome recognition
PCR if immuno compromised
How are varicella zoster jnfections prevented
Chicken pox vaccine (live vaccine)
Shingles vaccine: 2
Shingrex the best (2 shots)
VZ immunoglobulin: post exposure prophylaxis for congenital or immunodeficincy; given to newborns
Newborns may be given immunoglobulin and Acylovir
How are varicella zoster infections treated?
Airborne precautions in hospital (negatuve pressure room)
Acyclovir: immune compromised, varicella pneumonia or CNS infections
Describe coxsackie virus and echoviruses
Picornaviruses
Mostly summer/fall infection
Fecal oral transmission
50-80% asymptomatic
What are complications of coxsackie and echoviruses
Meningitis, myocarditis, handfoot and mouth
Describe hand foot and mouth disease
Mostly kids
Coxsackie A16
Sore throat, vesicles, fever, lesions including hand and feer
Describe human papilloma viruses
Small non enveloped icosahedral viruses
Circular doubke stranded viral DNA
More than 100 different types
How is HPV transmitted
Virus shed in cells from warty lesions on skin/mucous membranes
Infected cells multiply and form new lesions
Does HPV have viremia
No infection is limited to superficial tissue
What is skin to skin hpv
Platar warts or common warts caused by 1,2,3 and other types
What are low risk mucosal HPV infections
Low risk of cancer
HPV 6,11
Primarily associated with genital warts
What are high risk mucosal HPV infections
High risk of invasive cancer
HPV 16, 18 and others
What makes HPV potentially cancerous
Integrated gene gives rise to genomic instability causes growth of cells to become unrestricted
What cancers can be prevented by HPV vaccine
Cervical Oropharynx Anus Oral cavity Vulva Penile
How do we test for HPV?
In NS pap smear
Describe the HPV vaccine
Prevents virus replication by using virus outside and not the inside
What HPV types does the vaccine protect against
16, 18 (highest risk), 6,11 (low risk) and 5 other types
Can be given in 2 or 3 doses
Who should get the HPV vaccine
Males and females 9-26
MSM
Immunosuppressed
NOT RECCOMENDED FOR UNDER 9 AND PREGNANT MOTHERS
What are common gastroenteritis viruses
Noroviruses (MOST COMMON)
Rotaviruses
Enteric adenoviruses
Astrovirus
Describe noroviruses
Winter vomiting disease
Small RNA viruses, multiple serotypes
Adults more commonly affected
Very infectious
How are noroviruses transmitted
Fecal oral and aerosol spread
Describe rota viruses
Naked doubke stranded RNA viruses
Look like a wheel
Usually endemic, reduced with vaccine
Most severe in neonates and kids
Describe the pathogenisis of gastroenteritis viruses
Replicate in mucosal cells of the small intestine
Damage transport mechanisms
Loss of fluids and electrolytes
Little inflammation
How are enteric viruses spread
Poor hygiene and sanitation Fecal oral Contaminated water Food (filtering fish) Fomites
Desrcibe the transmission of gastroenteritis viruses
Highly trasmissible especially by convalescents; may be symptom free bht high numbers in stool for 48 hours and may shed for weeks
What are some symptoms of gastroenteritis viruses
Vomiting (esp norovirus) Occasionally fever Diarrhea Dehydration Electrolyte imbalance
Hiw are enteric viral infections diagnosed
Clinical syndrome
PCR for outbreaks
Antigen in stool (not as common)
How is viral gastroenteritis treated
Rehydration (IV elderly)
Anti motility agents
Pepto bismol
