Module 8: Influenza/Prenatal Pathogens Flashcards
What are the two antivirals approved for treatment of influenza A/B?
Zanamivir (Relenza), Oseltamivir (Tamiflu)
Therapy for primary influenza pneumonia is directed at maintaining what?
Oxygenation undertaken, aggressive reparatory/hemodynamic support
Infection of influenza for mother during pregnancy has a higher risk for __________ ____________ ______. Is there utero transfer?
Secondary bacterial pneumonia. No.
Influenza is a ______-stranded _______ virus with an ________ __________ __________. What are the 3 types?
Single, RNA, outer lipoprotein envelope. Types A, B, C.
Where are antigenic differences found on the internal structural proteins of influenza viruses?
- nucleocapsid
- matrix proteins
Influenza A viruses are further subdivided by which 2 surface antigens?
- hemagglutinin
- neuraminidase
What are some differences between influenza A, B, and C?
A: Infect people, animals, birds. Can cause epidemics & pandemics.
B: Infect humans, morbidity/mortality, less severe epidemics.
C: Mild illness, no epidemics.
Where does hemagglutinin bind to? How does an antibody inhibit it?
Binds to sialic acid to initiate infection.
Neutralizes the infectivity of virus, useful in vaccines.
What are the three functions of neuraminidase?
- binds sialic acid to release progeny virus from infected cell
- degrades protective layer of mucus in resp tract
- enhances ability of virus to infect resp tract
Describe the 2 types of antigenic changes?
- antigenic shifts: major changes on the re-assortment of segments of genome RNA
- antigenic drifts: minor changes due to mutations
Describe herd immunity.
Provided by vaccinated population, thought to prevent spread, protect non-vaccinated individuals.
What are the five herpes dsDNA enveloped viruses?
- HSV 1
- HSV 2
- VSV (varicella-zoster)
- EBV (epstein-barr)
- CMV (cytomegalovirus)
What are two distinguishing features of dsDNA viruses?
- envelop of lipid bilayer taken from host nuclear membrane
- ability to cause latent infections
What are symptoms of HSV1, how is it transmitted, and importance for pregnancy/postnatal?
Symptoms: cold sores
Transmission: indirect contact, kissing
Pregnancy: Reactivation during pregnancy, rare fetal transmission, but higher risk for postnatal infection
What are symptoms of HSV2, how is it transmitted, importance for pregnancy/postnatal?
Symptoms: Blisters on outer genital tissues
Transmission: Sex
Pregnancy: Rare fetal transmission, but high risk postnatal, treat infant with acyclovir
What is VSV and how is it transmitted?
Herpes that causes chickenpox, can later cause shingles. Transmitted by saliva or direct contact with vesicles.
Can fetal infection occur in VSV? When is it most dangerous? Which vaccination would be used for infant AFTER birth?
Yes, most dangerous <20 weeks. Varicella-zoster immune globulin (VZIG) is used to treat newborn, NO vaccination during pregnancy.
Why does shingles occur? How can it be prevented (2 methods)?
VSV is reactivated and emerges from nerve cells, usually due to reduced immunity in host.
1. Varivax for children
2. Zostavax for adults
NO vaccination during pregnancy
What are examples of reasons for HSV reactivation?
- febrile illnesses ex. common cold
- direct sunlight
- stress/trauma
- menstruation
- immunocompromised
How is EBV transmitted? What does it cause? Pregnancy implications?
Called the “kissing disease,” leads to mononucleosis. Fever, lethargy, sore throat, enlarged spleen, T cell response against B cells, B cell response against RBCs. EBV not associated with fetal infections.
What does CMV affect, what is it transmitted by? Pregnancy implications?
Infection of salivary glands and lung cells, transmitted by saliva & sex.
In utero transmission is possible - CNS disorders, deafness, rash, treatment with acyclovir.
What is hepatitis? Difference between chronic/acute?
Inflammation of liver, caused by hep virus, toxins, or drugs.
Chronic: detected by elevated liver enzymes in blood
Acute: jaundice, hepatic enlargement
What are distinguishing features of hep B? Transmission?
dsDNA enveloped, nucleocapsid core contains dsDNA, DNA polymerase, can cause chronic infection.
Transmission mainly by blood, sexual contact.
What is the likelihood of acute vs. chronic hepatitis from HBV? Mortaility?
Acute: 25% of HBV cases.
Chronic: 5-10% of HBV cases.
Mortality: Liver failure in acute, cancer, cirrhosis in chronic cases
What happens if a mother is discovered to be a carrier of hep B?
HBsAg vaccine, protect infant through antibodies. Hep B immunoglobin can be given if active infection, passes protection too.
Describe parvovirus, infection, pregnancy implications.
Small ssDNA viris, “slapped cheek” syndrome, 50% of population has had parvo.
Transmission: usually resp, can occur in utero
Pregnancy: mild illness, can rarely cause miscarriage
What is special about the structure of Hep A? Which is special about its pathology?
ssRNA, non-enveloped with a nucleocapsid. Causes 50% of acute viral hepatitis but NO chronic disease, NO carrier state, very mild.
How is Hep A transmitted, symptoms?
Fecal-oral route. Fever, dark urine, jaundice.
What are pregnancy implications for HAV?
Almost never transmitted in utero, no birth defects. IgG antibodies protect infant, vaccine available for during pregnancy.
___% of chronic state HCV leads to _____/_______. HCV represents __% of all chronic hepatitis cases.
80, cancer/liver cirrhosis, 50
HCV (can/can’t) be transferred from mother to fetus. There is a much higher chance of transmission if which disease is present? Which anti-viral cannot be used in pregnancy?
Can. HIV. Ribavirin, is a known teratogen (malformation-causer).
How is Hepatitis E transferred? Is there a chronic/carrier state? What are pregnancy implications? What is DIC?
Fecal-oral route. No. More severe acute disease in pregnant women, 20 mortality rate.
DIC = disseminated intravascular coagulation. Excessive clotting, kidney dysfunction caused by HEV causes mortality.
Is rubella enveloped? How can it be transferred, and prevented?
ssRNA, enveloped. Transferred via respiratory or through placenta. Prevented by MMR vaccine or natural infection (lifelong immunity).
Which malformations can occur due to rubella (3)?
Microcephaly, cataracts, heart defects.
What is HTLV-1 as a virus? How is it transmitted, and where is it prevalent? What implications does it have for newborns?
ssRNA, retrovirus, enveloped.
Transmitted via sex, blood, milk.
Endemic to Africa, South America, Caribbean.
Transfers through breast milk (20%), high risk for leukemia later.
What does HIV target? What implications does it have for newborns?
Kills CD4 t-cells, dendritic cells, CNS damage. 25% of infants with HIV+ mothers will have HIV.
Which 2 hepatitis viruses cause chronic infection and liver cancer?
HEP B and C
