Zika virus infection overview: Difference between revisions
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No vaccine against Zika virus currently exists. Since the virus is primarily transmitted through mosquitoes, effective measures to avoid mosquito bites include using insect repellent, installing mosquito bed nets and window/door screens, wearing long sleeves and long pants, and removing potential breeding sites from indoor/outdoor premises. | |||
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Revision as of 18:54, 22 December 2015
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Zika virus infection Microchapters |
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Diagnosis |
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Zika virus infection overview On the Web |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Nate Michalak, B.A.
Overview
Zika fever is an illness caused by the Zika virus, a member of the family Flaviviridae. The fever and virus are named after the Ugandan forest where the virus was first isolated. The virus is commonly found in Africa but has also been found in Malaysia and Micronesia. Symptoms are similar to dengue fever, but are milder in form and usually last four to seven days. No hemorrhagic manifestations have been documented. Common symptoms include a maculopapular skin rash that starts on the face or trunk before moving to the rest of the body, conjunctivitis, joint pain, low-grade fevers and headache.
Historical Perspective
Zika virus was first isolated from a rhesus Monkey in 1947 in Uganda. The virus was first isolated from humans in 1968 in Nigeria. Since then, viral circulation and outbreaks have been documented throughout Asia and Africa. The most recent outbreak occurred in Brazil in April 2015.
Pathophysiology
Causes
Zika virus infection is cause by Zika virus, an enveloped, single stranded positive sense RNA virus. Zika virus is a type of flavivirus and primarily transmitted through mosquitoes.
Classification
The illness caused by Zika virus is usually mild with symptoms lasting from several days to a week. Severe cases requiring hospitalization are uncommon.[1] A schema for classification of Zika virus infection is yet to be developed.
Differential Diagnosis
Zika virus infection's broad ranging clinical symptoms cause it to be commonly misdiagnosed with multiple similar diseases that are also from the Flaviviridae virus family. Zika virus infection has similar clinical presentation to dengue, yellow fever, West Nile virus, and Japanese encephalitis. Performing RT-PCR laboratory testing in conjunction with plaque-reduction neutralization techniques is the primary diagnostic method to determine and confirm Zika virus infection. Zika virus infection is distinct in its milder symptoms with short length. The emerging correlation between Zika virus infection and complications that include congenital anomalies and neurological syndromes is distinctive.
Epidemiology and Demographics
In 2015, Zika virus infection outbreaks rose dramatically, particularly in Brazil as observed by the manifestation of a correlated complication, microcephaly, in infants born to mothers with Zika virus infection, an incidence of 99.7/100,000 infants. The majority of Zika virus infection cases are reported in South Africa and Tropical Asia. As of 2014, Zika Virus infection outbreaks have become prevalent in South America as well. Cases reported in other regions of the world have come from infected travelers from areas experiencing outbreaks. Zika virus infection affects all age groups, with newborn infants particularly vulnerable due to risk of transmission from the mothers upon birth.
Risk Factors
The greatest risk factor for acquiring Zika virus is traveling to endemic areas. Other less potent risk factors include blood transfusion from infected donor, sexual transmission, and perinatal transmission to a fetus from an infected mother.
Natural History, Complications & Prognosis
Patients with Zika virus infection will develop symptoms between 3 and 12 days upon contracting the disease. Symptoms will typically begin with a mild headache and progress to include a macropapular rash spread across the body within 24 hours, followed by fever, malaise, and back pain. The symptoms typically last from 4-7 days and will fade and an alleviate by the end of a week. The prognosis is excellent, with a full recovery expected with minimal hospitalization and treatment limited to symptoms. Complications can arise through Congenital and Neurological disorders as a result of Zika virus infection; prognosis may be worse in the presence of these complications.
Diagnosis
History and Symptoms
Patients infected with Zika virus typically experience mild symptoms that last several days to a week. Symptoms include acute onset of fever, maculopapular rash, arthralgia, conjunctivitis, myalgia, headache, retro-orbital pain, and nausea and vomiting. Hospitalization from this disease is rare and not deaths have been reported.
Physical Examination
Laboratory Findings
Blood serum and plasma testing is conducted to detect viral nucleic acids or virus specific IgM. Laboratory testing is the primary source when differentiating between Zika and other commonly misdiagnosed viruses.
Biopsy
Treatment
Medical Therapy
There is currently no antiviral treatment for Zika virus. Suggested therapy includes rest, fluids antipyretics and analgesics. NSAIDs should be avoided until dengue fever is ruled out as a potential diagnosis.
Surgery
Prevention
No vaccine against Zika virus currently exists. Since the virus is primarily transmitted through mosquitoes, effective measures to avoid mosquito bites include using insect repellent, installing mosquito bed nets and window/door screens, wearing long sleeves and long pants, and removing potential breeding sites from indoor/outdoor premises.