Vector is the mosquito, Aedes aegyptiin urban type, A. hemogogusin jungle type. Man is only reservoir in urban type, monkeys in jungle type. Increasing problem is Africa and S. America; could reappear in US
Sx:Malaise and jaundice
Si:
Icterus; tender liver; fever >105°F (40.5°C); minimal tachycardia
r/o salmonella, gram-negative shock, psittacosis, and Q fever
Hepatic or renal failure, myocarditis
r/o malaria; leptospirosis; viral hepatitis; typhus; ebola virus
r/o DENGUE (Nejm 2005;353:924; Jama 1997;277:1546), mosquito-transmitted febrile illness often with exanthematous rash, low wbc and platelet counts; usually benign course, possibly helped by vaccination vs Japanese encephalitis (Nejm 1988;319:808)
Lab:
Chem:Elevated LFTs
Path:Liver bx shows viral hepatitis picture but more irregular necrosis and Councilman bodies which are questionably distinguishable from Mallory's bodies
Serol:IgM antibodies
Rx:
Prevent by spraying to kill mosquitos if >5-10% homes have Aedes.
Vaccine, live virus; effective in 1 wk; use in endemic areas, eg, South America and Africa; 0.5 cc sc; lasts 10+ yr; egg base (Ann IM 1969;71:365); available at special distribution centers in US; reports of hepatitis, encephalitis, anaphylaxis, multisystem organ failure and death after live virus vaccination in 3/100,000 (Lancet 2001;358:91, 98, 121); killed virus vaccine risks lower and immunity greater (Nejm 2011;364:1326)