Arboviruses Flashcards
What are the common characteristics of arboviruses
Fever + Encephalitis and/or arthritis and/or hemorrhage
arbovirus principle reservoir, vector
Vertebrate animals (usually small mammals or birds) but sometimes in epidemics, humans (though usually dead end hosts)
Mosquito is vector
Sylvatic cycle
primate reservoir, transmitted by forest mosquitos
emergence cycle
humans infected by sylavatic mosquitos, passed to urban
urban cycle
human reservoir, transmitted by urban mosquitos, sedes aegypti
clinical presentation of chikungunya
bipashic fever
small joints polyarthralgia, Bilateral
symmetric polyarthralgias of the hands and feet
chikungunya
difference between CHKV and Dengue
CHKV has arthritis and NO hemoconcentration
What are the diagnostic tests for chikungunya
Viral culture (<3 days), rtPCR (<8 days), IgM antibody (> days)
Tx chikungunya
symptomatic therapy, NSAIDs, sometimes low dose steroids
66yoM From Lima with fever, arthritis, 7 days fever HA muscle pain, then rash. DDx?
Mayaro v. Dengue v. Chik ; generally, arthritogenic alpha viruses (mayaro in this case)
23year old female from lima with 4 days of fever, chills, malaise, myagias, arthralgias, HA after travel to iquitos. No rash, bleeding, jaundice, abdominal pain, cough, SOB, GI Sx. Then non-purulent conjunctivitis
Zika Virus (flavivirus)
Zika virus transmission
mosquitos, Virus RNA in semen (sexual transmission), some transplacental and perinatal infection, blood transfusion
symptoms of zika
rash, fever, arthralgias, conjunctivitis, myalgias, headache
similarities and differences between zika, chkv, dengue
congenital zika syndrome
calcifications, atrophy, microcephaly, fontanelle closure, joint problems, strabismus
hyporeflexia, leg weakness, leg paresthesia, arm weakness, dysphagia
guillain barre in zika
how to diagnose zika
real time PCR in serum/urine <14 days; serology IgM>14th day
If a pregnant asymptomatic woman, but exposed to zika, when do you test
NAT testing for Zika 3 times during pregnancy
Lab interpretation: ZIK , Deng neg, Chik neg
likely zika
If zika, dengue, and chik are all positive
its a flavivirus infection + Chik co infection
Difference between CHIKungunya and ZIKA
Chikungunya: symptomatic fever, athralgia, rash arhtiritis (can be chronic)
ZIKA: Mild illness, low fever, pruritic rash, conjunctivitis, could be associated with GBS
What are the flaviviruses that cause hemorrhagic fever and encephalitis?
WNV
JE
St. Louis encephaltiis
Tick born encephalitis
Murray Valley enceph
Japanese encephalitis is endemic where
Asia (Japan, taiwan, korea, china; malaysia, indonesia, philippines)
Vector of JEV
Culex species
Hosts of JE Virus
Bird: viremic, reservoir and amplyfying host
Pig: Abortion, death; major amplifying host
Human: Encephalitis, non-transmitting/dead end host
Meningitis, encephalitis, acute flaccid paralysis
Japanese encephalitis
seizures, CT shows lesions in basal ganglia, acute flaccid paralysis , LP shows normal to increase protein, pleocytosis, mainly lymphs, normal glucose
Japanese encephalitis
T2 MRI with bilateral thalamic involvement-JEV Encephalitis
How do you diagnose JEV
PCR can be positive; CSF IgM
Vaccine for JE
inactivated vaccine, 2 doses 28 days apart; if exposed >1 month to rural areas during the rainy season
