Strep/Mono/Vectors Flashcards

Question

Streptococcus agalactiae (Group B Strep) Disease - Signs & Symptoms

Answer 1

Skin & soft tissue infections Neonatal infection during birth

Answer 2

Human herpes virus that infects B lymps Causes infectious mononucleosis, burkitt lymphoma, neoplasms of thymus/parotid gland/supraglottic larynx Can compicate cardio, ocular, respiratory, hematologic, digestive, renal & neurologic symtoms (so everything)

Answer 3

~95% world population has been exposed Herpes DNA virus that infects B lymphs Variant lymphs produced have T cell characteristics (mononucleosis from large effector CD8 Tc cell reponse against EBV infection of circulating B cells) Transmitted by oral-pharyngeal secretions touching *smooch*. Can also be trasmitted by blood transfusion or transplacental route (not common).

Answer 4

Major concern! Infectious mononucleosis postperfusion syndrome -blood transfusion from immune donor to nonimmune recipient -may be from CMV rather than EBV Maintain EBV as chronic, latent infection Low % of patients experience symptomatic reactivation

Answer 5

Asymptomatic for most infants (they ain't got no B cells lieutenant dan) Typical illness in teens Incubation 10-50 days Extreme fatigue, malaise, sore throat, fever, cervical lymphadenopathy. Splenomegaly in 50% of cases. Rare jaundice. Lasts 1-4 weeks. Significant # of patients do not manifest cassic signs (cool cool cool)

Answer 6

High leukocytes in most cases (10-20 x 10^9). 10% of patients leukopenic. Relative lymph counts 60-90% (with 5-30% of those being mono/varient lymphs) Increase in virus specific CD8+ T cells (important for life-long control of EBV disease) Serologic antibody testing for non-classic symptoms. Abs present are heterophile & EBV.

Answer 7

Broad class, may be present in low concentrations in healthy person. Titer of > 1:56 clinically significant for suspected mono. IgM appears in acute phase (IgM reacts with horse/ox/sheep RBCs, absorbed by beef RBCs, not absorbed by guinea pig kidney cells, does not react with EBV specific antigens)

Answer 8

10-20% of adults don't produce heterophile antibodies 50%+ of kids younger than 4 with mono are heterophile negative EBV serology recommended for people without classic symptoms, heterophile negative, immunosuppressed EBV infected B cells express new antigens encorded by virus Viral capsid antigen, early antigen & nuclear antigen all corresponding antibody responses -assays for IgM & IgG antibodies to these EBV antigens are available

Answer 9

produced by infected B cells & found in cytoplasm Anti-VCA IgM detectable, but low concentration, in early infection. Desappears ~2-4 months. Anti-VCA IgG detectable within 4-7 days and persis for a long time, possibly forever

Answer 10

Early antigen-diffuse (EA-D) -found in nucleus & cytoplasm of B cells -IgG type (indicative of acute infection) Early antigen-restriced (EA-R) -Found as a mass only in cytoplasm -IgG usually only seen in young children Neither consistent indicators of disease stage

Answer 11

Found in nucleus of all EBV infected cells Anti-EBNA IgG doesn't appear until patient has entered convalescence Titers gradually increase and reach plateau 3-12 months after infection Most healthy individuals with previous exposures have titers ranging from 1:10 - 1:160 Should be taked in combination with patient symptoms, history & Ab response patterns

Answer 12

No previous exposure: negative Recent acute infection: positive Past infection (convalescent): positive Reactivation of latent infecgtion: positive

Answer 13

No previous exposure: negative Recent acute infection: negative Past infection (convalescent): positive Reactivation of latent infecgtion: positive

Answer 14

Common method for EBV serology Antigen substrate slide containing EBV infected cells incubate with serum Fluorescein-conjugated antihuman IgG or IgM Cons: time consuming, difficult to interpret, prone to interference from other serum components

Answer 15

Bacterial/viral diseases transmitted by mosquitoes, ticks & fleas Travelers & military at highest risk Discovery and surveillance often done with serologic testing

Answer 16

Spirochete Borrelia burgdorferi Transmitted by Ixodes ticks. Can be carried into household on dogs & cats. White footed mouse for larval and nymphal stages. White tailed deer for adult stages.

Answer 17

Most common vector-borne illness in US (95%!). But found worldwide. NE and upper midwest.

Answer 18

After tick bite, spirochetes migrate outwardly into skin (skin lesions, erthema chronicum migrans (ECM)) 60-80% begin with flu like symptoms, evolves through stages. Bullseye rash. Most patients have ECM (50% of these patients develop secondary lesions), .25% have arthritis. Rarely, neurologic & cardiac issues.

Answer 19

~4 weeks afater infection ECM or other skin eruptions, flulike symptoms, neurologic symptoms

Answer 20

Variable latent period Nervous system, heart, eyes, skin can all manifest abnormalities

Answer 21

Weeks to years later Arthritis, late neurologic complications, acrodermatitis chronica atrophicans

Answer 22

Common sign of early Lyme May be associated with long-standing infiltration of the joints by spirochetes along with local inflammatory response

Answer 23

Lyme carditis in ~8% of untreated patients within 1-2 months Lightheadedness, syncope, dyspnea, palpitations, chest pain Usually self-limited and mild course

Answer 24

~15% of untreated patients 2-8 weeks after onset Aseptic meningitis, cranial nerve palsies, peripheral radiculoneuitis, peripheral neuropathy Severe headache, mild neck stiffness Maybe chronic encephalopathy

Answer 25

Transplancental transmission possible Infant dies shortly after birth, mother acquired infection early in pregnancy with no treatment

Answer 26

Cellular immune responses begin concurrent with early clinical illness Increase in spontaneous suppressor cell activity and reduction in NK cell activity Mononuclear cell, Ag specific responsese develop during spirochete dissemination and humoral respones soon follow Serodiagnostic tests insensitive during first several weeks After 1 month, most patients have IgG antibodies - both IgM & IgG can persist for years Ab formed: cryoglobulins, immune complexes, antibodies to B. burgdorferi, anticardiolipin antibodies

Answer 27

Culter is definitive diagnosis, but rare. Usually from biopsy samples, less often from plasma or CSF. Usually based on clinical findings, history of exposure, antibody response to B. burgdorferi Might find spirochetes in a blood smear! But very transient, will be there one day, gone the next

Answer 28

CDC recommends two step process EIA or IFA, then Western blot Only positive if BOTH tests are positive

Answer 29

Verifies reactivity of antibody to surface/flagellar protein of B. burgdorferi Helpful in borderline results More definitive test later in disease

Answer 30

Standard test method Low sensitivity, lengthy processing time

Answer 31

Detects spirochetes in synovial fluid from joints, other samples Directly IDs pathogen, useful when patient is seronegative

Answer 32

Not recommended unless patied has pronouced neurological manifestations

Answer 33

How long tick was attached, probability of tick being a carrier, risk of antibiotic reactions all influence treatment decisions Antibiotics -tetracyclines (bacteriostatic unless in high doses) -amoxicillin (more effective than penicillin) -unclear if antimicrobial treatment will prevent Lyme disease

Answer 34

None really! No vaccine. Check for ticks, wear light-colored clothes, tuck socks into pants

Answer 35

First described in US in 1986 Can be fatal, needs prompt treatment! Tick-borne rickettsiae, genus Ehrlichia Ehrlichia chaffeensis - agent of human monocytic ehrlichiosis in us

Answer 36

Prevelance in low, primarily southern Mid-Atlantic & south central states during spring and summer Lone Star Tick main vector for E. chaffeensis. White tailed deer principle reservoir. In easern US, maybe white-footed mouse.

Answer 37

'Ehrlichiosis' is the general term for human granulocytic ehrlichiosis (now called anaplasmosis) and human monocytic ehrlichiosis (HME) Most patients not suspected of having rickettsial infection. Symptoms nonspecific: fever, chills, headache

Answer 38

Elementary bodies enter leukocyte by phagocytosis, multiply rapidly 3-5 days later, tightly packed elementary bodies visible Over 7-12 days, initial bodies developp into morular (mulberry) forms

Answer 39

Direct observation on Wright-Giemsa stain (rapid, inexpensive) PCR test of skin biopsy of rash or EDTA whole blood Specific immunohistochemical detection In anaplasmosis: diagnosis by seroconversion or by single titer higher than 1:80 w/ supporting systems

Answer 40

Doxycycline (no guideline for long term therapy) Prevention/reducing tick exposures

Answer 41

RMSF - tick-borne disease caused by bacterium Rickettsia rickettsii found in N & S America Transmitted by American dog tick , Rocky Mountain wood tick, brown dog tick

Answer 42

Reported since 1920 in every state except Vermont & Maine Geographic distribution tied to location of various tick species Most illness reported in June and July

Answer 43

First symptoms 2-14 days after bite, often go unnoticed Sudden onset of fever and headache, 90% have rash, some nausea & vomiting

Answer 44

If rash present: PCR on biopsy or immunohistochemical staining Ab detected within 7-10 days (85% negative during first week) IFA with 2 paired specimens with four-fold increase in titers the gold standard. First sample asap, second 2-4 weeks later both IgM & IgG remain elevated for months

Answer 45

Earlier treatment corresponds to quicker recovery. Doxycycline first line of treatment, most effective if started before 5th day of symptoms. Durations of treatment 7-14 days. IV antibiotics, prolonged hospitilization, intensive care for more sever course

Answer 46

Rare, severe, sometimes fatal Tick-borne, caused by Babesia (microscopic parasite that infects RBCs)

Answer 47

Reportable in 37 states Transmitted by I. scapularis tick. Larvae feed on white-footed mouse, nymphs and adults feed on white-tailed deer Most common in older individuals, splenectomized patients, immunocompromised

Answer 48

Incubation period 7-21 days—may take 1-8 weeks for symptoms to appear Clinical presentation is variable: ranges from asymptomatic to rapidly progressive and sometime fatal Disease can cause fever, fatigue, and hemolytic anemia lasting several days to months

Answer 49

Observation of parasites in blood (symptomatic people) Difficult to distinguish from malaria, can used PCR No test is approved for blood donors :)

Answer 50

No standardized treatments have been developed Some drugs used for malarial treatment have shown effectiveness Antibiotic therapy recommended for splenectomized or immunodeficient patients Combo of azithromycin and oral quinine Exchange transfusion for patients with high level of parasites (>10%), severe disease, or massive hemolysis Prevention requires diligence in tick infested areas

Answer 51

Chikungunya virus is transmitted through mosquito bites Outbreaks in Africa, Asia, Europe, and the Indian and Pacific Oceans U.S. cases from returning travelers

Answer 52

Symptoms begin 3-7 days after bitten by infected mosquito Fever, joint pain, headache, rash, joint swelling

Answer 53

IgM and IgG antibody testing by ELISA method IgM suggests new, active infection IgG suggests current or past infection Parallel testing of acute and convalescent together suggested

Answer 54

No vaccine! Prevent mosquito bites Treatment to relieve fever/pain only option...

Answer 55

Dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) Caused by 4 related viruses (1-4 serotypes) Transmitted by mosquitos

Answer 56

Endemic in at least 100 countries Most cases in U.S. acquired by travelers

Answer 57

Fever and Two of the following: nausea, vomiting, rash, aches and pains, leukopenia, positive tourniquet test

Answer 58

Can include any of the following: abdominal pain and tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleeding, lethargy, restlessness, liver enlargement >2 cm, lab finding of increases hct, red cell mass concurrent with rapid decrease in platelet count

Answer 59

Must include dengue symptoms with at least one of: Severe plasma leakage leading to shock (DSS) or fluid accumulations with respiratory distress; severe bleeding; severe organ involvement: Liver- AST or ALT >1000, CNS-impaired consciousness, failure of heart and other organs

Answer 60

CDC: Testing is divided into confirmatory testing and testing for probably or suspected dengue infection Probable testing (Detection on IgM anti-DENV) Suspected testing (Absence of IgM anti-DENV) Dengue infection results in long-lasting immunity with a specific serotype—crossreactive protection is shortlived (1-3 years)

Answer 61

No vaccines available—prevent mosquito bites Treatment is consistent with classification of disease

Answer 62

WNV-member of Japanese encephalitis virus group of flaviviruses Mosquito-borne pathogen Has been in the U.S. since at least summer of 1999

Answer 63

Fever, headache, fatigue, aches, sometimes a rash Can last a few days to several weeks

Answer 64

Serologic tests or virus isolation IgM antibody—7-8 days after symptom onset IgG antibody 3-4 weeks Some FDA approved ELISA kits available—need confirmation by CDC or state health lab

Answer 65

No specific treatment—mild cases resolve over time More severe cases with hospitalization—supportive treatment including IVs Prevent mosquito bites

Answer 66

Infection during pregnancy—can cause microencephaly—incomplete brain development and other severe fatal brain defects; also have eye defects, hearing defects, impaired growth Many people won’t have symptoms or only mild: fever, rash, joint pain, conjunctivitis—can last for several days to a week

Answer 67

Spread primarily by the bite of an infected Aedes spp. Mosquito Pregnant women can transmit to fetus Sexual contact Typically tropical areas; Puerto Rico and Florida High point in 2016—5168 symptomatic cases in U.S. 2018– 74 Zika cases

Answer 68

Based on person’s recent travel history, symptoms, and test results Molecular Assay -rRT-PCR for RNA performed on paired serum and urine samples Serologic Test -IgM typically develop at end of first week of illness Zika MAC-ELISA -Used for qualitative detection of IgM antibodies in serum or CSF -Has some nonspecific cross-reactivity