Condition	Pathogen	Vector	Clinical presentation	Diagnosis	Treatment options	Prevention
Chikungunya	Chikungunya virus	Aedes mosquito	Fever (abrupt onset, remitting recurring), shaking chills, immobilizing arthralgias (especially in small joints), rash (initial flushing develops into a maculopapular rash on the trunk and limbs), myalgias, pharyngitis Generally self-limited but may have long-term sequelae Laboratory: leukopenia with relative lymphocytosis (often normal); thrombocytopenia	Clinical: severe arthralgias, largely indistinguishable from dengue Serologic and molecular diagnostics are available Positive findings on viral culture of serum; may not be detectable in first two weeks of illness	Acute supportive care: analgesics, antipyretics Chronic arthralgias: nonsteroidal anti-inflammatory drugs, corticosteroids; chloroquine (Aralen) and hydroxychloroquine (Plaquenil) in refractory cases	No vaccine available Mosquito control and avoidance* Nationally notifiable disease†
Dengue	Dengue virus	Aedes mosquito	Fever (abrupt onset), severe myalgias and bone pain, rash, mild bleeding (positive tourniquet test result); can progress, after defervescence, to capillary leak syndrome and severe bleeding diathesis (dengue hemorrhagic fever or dengue shock syndrome); potentially fatal, but this is rare if well managed Laboratory: leukopenia, thrombocytopenia, mild transaminitis	Clinical: severe myalgias and arthralgias; characteristic erythematous and confluent rash on limbs with patches of unaffected skin Serologic testing is available but may cross-react with other Flaviviridae Antigenic and molecular diagnostics are not widely available	Supportive care: analgesics, antipyretics (aspirin and nonsteroidal anti-inflammatory drugs should be avoided), aggressive but judicious fluid resuscitation, blood product replacement	No vaccine available in the United States (newly available in Mexico) Mosquito control and avoidance* Nationally notifiable disease†
West Nile virus infection	West Nile virus	Culex, Ochlerotatus, Culiseta, and Aedes mosquitoes	Fever (acute onset), headache, malaise, myalgias, arthralgias, retro-orbital pain; often nausea, vomiting, diarrhea, brief rash; rarely central nervous system involvement (mostly in older persons) leading to acute flaccid paralysis (like polio), typically with meningoencephalitis; the neuroinvasive form may be fatal Laboratory: pleocytosis in patients with central nervous system disease (initially neutrophilic and subsequently lymphocytic); elevated cerebrospinal fluid protein; may have hyponatremia	Clinical: self-limited, nonspecific flulike illness; a maculopapular eruption with defervescence is typical Serologic testing is available but may cross-react with other Flaviviridae; may not be detectable in first week of illness Antigenic, molecular, and culture methods lack sensitivity	Supportive care: analgesics, antipyretics	No vaccine available Mosquito control and avoidance* Blood donor screening Nationally notifiable disease†
Zika virus infection	Zika virus	Aedes species mosquito [corrected]	Fever, rash, myalgias, arthralgias, headache, conjunctivitis; generally self-limited If a pregnant woman is infected, there is a risk of fetal microcephaly and malformations Laboratory: nonspecific	Clinical: nonspecific viral syndrome Serology is available, but may cross-react with other Flaviviridae; molecular testing is also available Viral culture has low sensitivity Real-time reverse transcriptase polymerase chain reaction testing of urine is recommended if symptoms began less than 14 days earlier	Supportive care: analgesics, antipyretics (not aspirin)	No vaccine available (in phase I trials) Mosquito control and avoidance* Nationally notifiable disease† Use of condoms may decrease the risk of sexual transmission