Zika virus infection pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Yazan Daaboul, M.D.; Nate Michalak, B.A.; Serge Korjian M.D.; Yamuna Kondapally, M.B.B.S[2]
Overview
Zika virus is a vector-borne pathogen transmitted via the Aedes mosquito that also transmit the dengue and chikungunya viruses. Human-to-human transmission may be possible by sexual intercourse but has not been confirmed. Zika virus is thought to initially replicate in dendritic cells near the site of inoculation before spreading to lymph nodes and then the bloodstream.
Pathophysiology
Transmission
Through mosquito Bites
Zika virus is primarily transmitted to humans via the bite of an infected Aedes mosquito. These mosquitoes are also vectors for dengue and chikungunya viruses.[2][3]
From mother to child
- Infected pregnant women can transmit the Zika virus during the pregnancy or around the time of birth.[3]
- There are no reports of infants acquiring Zika virus through breastfeeding. Because of nutritional benefits, mothers are encouraged to breastfeed even in areas where Zika virus is found.
Sexual transmission
Zika virus has also been suspected to be sexually transmitted between humans.
- Asymptomatic males to their female partners
- Symptomatic female to her male partner
- Longer shedding of Zika virus in semen
- The maximum documented time of Zika virus RNA detection in semen after onset of symptoms is 188 days
Blood transfusion
- Transmission through blood transfusion is possible as Zika virus has been identified in asymptomatic donors during an ongoing outbreak.[3][4]
Laboratory exposure
- There has been one reported case laboratory-acquired Zika virus disease in United States.[3]
Pathogenesis
- Mosquito-borne Zika virus is thought to initially replicate in dendritic cells near the site of inoculation before spreading to lymph nodes and then the bloodstream.
- One study indicates that Zika virus replicates in cellular nuclei, as opposed to other flaviviruses that do so in the cytoplasm.[5]
- Virus is detectable in blood with in 3 to 4 days of symptom onset.
- The virus can be detected in blood, urine, cerebrospinal fluid, amniotic fluid, semen and saliva.
- The maximum documented time of Zika virus RNA detection in semen after onset of symptoms is 188 days.
- Zika virus can be killed by potassium permanganate, ether, temperatures >60°C, but is not effectively neutralized by 10% ethanol.[2]
Fetus
- The exact pathogenesis of Zika virus infection in fetus is not fully understood.
- It is thought that Zika virus infects the human embryonic cortical neural progenitor cells (hNPCs) which lead to disruption of cell cycle, increased cell death, and gene dysregulation.
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Gross pathology
On gross pathology the characteristic findings of Zika virus infection in neonate include:[6][7]
- Microcephaly
- Wide spread brain calcifications in the cortex and sub cortical white matter
- Ventricular enlargement secondary to cerebral atrophy
Associated Conditions
- There was a significant increase in patients with Guillain-Barré syndrome and congenital microcephaly during the 2014 Zika virus outbreak in French Polynesia and 2015 Zika virus outbreak in Brazil.
- A causal relationship between Zika virus infection and neurological/neurodevelopmental impairments in currently under investigation.[8]
References
- ↑ Zika virus transmission https://www.cdc.gov/zika/transmission/index.html(2016) Accessed on September 14,2016
- ↑ 2.0 2.1 Hayes EB (2009). "Zika virus outside Africa". Emerg Infect Dis. 15 (9): 1347–50. doi:10.3201/eid1509.090442. PMC 2819875. PMID 19788800.
- ↑ 3.0 3.1 3.2 3.3 Zika Virus Transmission. Centers for Disease Control and Prevention (June 1, 2015). http://www.cdc.gov/zika/transmission/index.html Accessed on December 17, 2015
- ↑ Musso D, Nhan T, Robin E, Roche C, Bierlaire D, Zisou K; et al. (2014). "Potential for Zika virus transmission through blood transfusion demonstrated during an outbreak in French Polynesia, November 2013 to February 2014". Euro Surveill. 19 (14). PMID 24739982.
- ↑ Buckley A, Gould EA (1988). "Detection of virus-specific antigen in the nuclei or nucleoli of cells infected with Zika or Langat virus". J Gen Virol. 69 ( Pt 8): 1913–20. doi:10.1099/0022-1317-69-8-1913. PMID 2841406.
- ↑ Sampathkumar P, Sanchez JL (2016). "Zika Virus in the Americas: A Review for Clinicians". Mayo Clin. Proc. 91 (4): 514–21. doi:10.1016/j.mayocp.2016.02.017. PMID 27046524.
- ↑ Mlakar J, Korva M, Tul N, Popović M, Poljšak-Prijatelj M, Mraz J, Kolenc M, Resman Rus K, Vesnaver Vipotnik T, Fabjan Vodušek V, Vizjak A, Pižem J, Petrovec M, Avšič Županc T (2016). "Zika Virus Associated with Microcephaly". N. Engl. J. Med. 374 (10): 951–8. doi:10.1056/NEJMoa1600651. PMID 26862926.
- ↑ Factsheet for health professionals. European Centre for Disease PRevention and Control (November 27, 2015). http://ecdc.europa.eu/en/healthtopics/zika_virus_infection/factsheet-health-professionals/Pages/factsheet_health_professionals.aspx Accessed on December 21, 2015.