West nile virus screening: Difference between revisions

Jump to navigation Jump to search
m (Changes made per Mahshid's request)
 
(17 intermediate revisions by 2 users not shown)
Line 1: Line 1:
{{West nile virus}}
{{West nile virus}}
{{CMG}}
{{CMG}}; {{AE}} {{YD}}


==Overview==
==Overview==
Universal screening for WNV is not recommended. As blood and transplant-related transmissions of the virus have been reported, nucleic acid tests (NAT) may be used to screen for WNV among potential blood and solid organ donors. In blood donation, individual screening is not recommended either. Instead, a "minipool" nucleic acid testing program (MP NAT) is implemented. Positive pools warrant further investigation for individuals. Patients with positive NAT may not donate blood or solid organs for at least 120 days. Re-testing after 120 days is indicated.


==Screening==
==Screening==
Commercial kits for human serologic diagnosis of WNV infection are currently in development. Until these kits are available, the CDC-defined IgM and IgG ELISA should be the front-line tests for serum and CSF.46-48 These ELISA tests are the most sensitive screening assays available. The HI and indirect immunofluorescent antibody (IFA) test may also be used to screen samples for flavivirus antibodies.
Universal screening for WNV is not recommended. Screening is only recommended for blood and solid organ transplant donors.
[http://www.cdc.gov/ncidod/dvbid/westnile/resources/wnv-guidelines-aug-2003.pdf]


==Surveillance methods==
===Screening donor blood products===
Following the discovery of WNV transmission by blood transfusions, WNV blood donor screening is performed using nucleic acid testing (NAT). A "minipool" nucleic acid testing program (MP NAT) is currently implemented to detect WNV viremia among donors. In contrast, serological testing is not feasible for screening purposes because IgM seroconversion may be detectable approximately 5 months following infection.<ref name="OPTN">{{cite web |url=http://optn.transplant.hrsa.gov/SharedContentDocuments/West_Nile_Virus_Living_Donors.pdf |title= Identifying risk factors for West Nile virus (WNV) during evaluation of potential living donors|last1= |first1= |last2= |first2= |date=2013 |website= United Network for Organ Sharing|publisher=The Organ Procurement and Transplantation Network|accessdate=09/11/2014}}</ref> Pools with positive NAT results warrant further investigation for individual screening. Individual patients with positive NAT may not donate blood for at least 120 days.<ref name="pmid16079368">{{cite journal| author=Stramer SL, Fang CT, Foster GA, Wagner AG, Brodsky JP, Dodd RY| title=West Nile virus among blood donors in the United States, 2003 and 2004. | journal=N Engl J Med | year= 2005 | volume= 353 | issue= 5 | pages= 451-9 | pmid=16079368 | doi=10.1056/NEJMoa044333 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16079368  }} </ref><ref name="pmid16079369">{{cite journal| author=Busch MP, Caglioti S, Robertson EF, McAuley JD, Tobler LH, Kamel H et al.| title=Screening the blood supply for West Nile virus RNA by nucleic acid amplification testing. | journal=N Engl J Med | year= 2005 | volume= 353 | issue= 5 | pages= 460-7 | pmid=16079369 | doi=10.1056/NEJMoa044029 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16079369  }} </ref><ref name="pmid15819665">{{cite journal| author=Kleinman S, Glynn SA, Busch M, Todd D, Powell L, Pietrelli L et al.| title=The 2003 West Nile virus United States epidemic: the America's Blood Centers experience. | journal=Transfusion | year= 2005 | volume= 45 | issue= 4 | pages= 469-79 | pmid=15819665 | doi=10.1111/j.0041-1132.2005.04315.x | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15819665  }} </ref><ref name="OPTN">{{cite web |url=http://optn.transplant.hrsa.gov/SharedContentDocuments/West_Nile_Virus_Living_Donors.pdf |title= Identifying risk factors for West Nile virus (WNV) during evaluation of potential living donors|last1= |first1= |last2= |first2= |date=2013 |website= United Network for Organ Sharing|publisher=The Organ Procurement and Transplantation Network|accessdate=09/11/2014}}</ref>


West Nile virus can be sampled from the environment by the [[pooling]] of trapped mosquitoes, testing avian blood samples drawn from wild birds and sentinel monkeys, as well as testing brains of dead birds found by various animal control agencies and the public. Testing of the mosquito samples requires the use of [[RT-PCR]] to directly amplify and show the presence of virus in the submitted samples. When using the blood sera of wild bird and sentinel chickens, samples must be tested for the presence of West Nile virus [[antibodies]] by use of [[immunohistochemistry]] (IHC)<ref>{{cite journal | first = M | last = Jozan | coauthors = Evans R, McLean R, Hall R, Tangredi B, Reed L, Scott J | year = 2003 | month = Fall | title = Detection of West Nile virus infection in birds in the United States by blocking ELISA and immunohistochemistry | journal = Vector-borne and Zoonotic Diseases | volume = 3 | issue = 3 | pages = 99-110 | id = PMID 14511579}}</ref> or Enzyme-Linked Immunosorbent Assay (ELISA).<ref>{{cite journal | first = RA | last = Hall | coauthors = Broom AK, Hartnett AC, Howard MJ, Mackenzie JS | year = 1995 | month = Feb | title = Immunodominant epitopes on the NS1 protein of MVE and KUN viruses serve as targets for a blocking ELISA to detect virus-specific antibodies in sentinel animal serum | journal = Journal of Virological Methods | volume = 51 | issue = 2-3 | pages = 201-10 | id = PMID 7738140}}</ref>
===Screening solid organ transplant donors===
 
Although the only data on human-to-human transmission by organ transplantation is derived from reports that included deceased donors, transmission to recipients may still occur if donors have NAT-negative IgM-positive results. These findings suggest that clearance of the WNV from solid organs may be delayed compared to its clearance from plasma. Accordingly, screening for WNV among transplant donors is recommended using NAT. There is no evidence to demonstrate the optimal time for solid organ donation in cases of positive NAT, but re-testing after 120 days to confirm negative NAT has become common practice. Patients with negative results after 120 days may donate solid organs.<ref name="OPTN">{{cite web |url=http://optn.transplant.hrsa.gov/SharedContentDocuments/West_Nile_Virus_Living_Donors.pdf |title= Identifying risk factors for West Nile virus (WNV) during evaluation of potential living donors|last1= |first1= |last2= |first2= |date=2013 |website= United Network for Organ Sharing|publisher=The Organ Procurement and Transplantation Network|accessdate=09/11/2014}}</ref>
Dead birds, after [[necropsy]], have their various tissues tested for virus by either [[RT-PCR]] or immunohistochemistry, where virus shows up as brown stained tissue because of a substrate-[[enzyme]] reaction.


==References==
==References==
Line 21: Line 21:


[[Category:Disease]]
[[Category:Disease]]
[[Category:Infectious disease]]
 
[[Category:Neurology]]
[[Category:Neurology]]

Latest revision as of 19:28, 18 September 2017

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Yazan Daaboul, M.D.

Overview

Universal screening for WNV is not recommended. As blood and transplant-related transmissions of the virus have been reported, nucleic acid tests (NAT) may be used to screen for WNV among potential blood and solid organ donors. In blood donation, individual screening is not recommended either. Instead, a "minipool" nucleic acid testing program (MP NAT) is implemented. Positive pools warrant further investigation for individuals. Patients with positive NAT may not donate blood or solid organs for at least 120 days. Re-testing after 120 days is indicated.

Screening

Universal screening for WNV is not recommended. Screening is only recommended for blood and solid organ transplant donors.

Screening donor blood products

Following the discovery of WNV transmission by blood transfusions, WNV blood donor screening is performed using nucleic acid testing (NAT). A "minipool" nucleic acid testing program (MP NAT) is currently implemented to detect WNV viremia among donors. In contrast, serological testing is not feasible for screening purposes because IgM seroconversion may be detectable approximately 5 months following infection.[1] Pools with positive NAT results warrant further investigation for individual screening. Individual patients with positive NAT may not donate blood for at least 120 days.[2][3][4][1]

Screening solid organ transplant donors

Although the only data on human-to-human transmission by organ transplantation is derived from reports that included deceased donors, transmission to recipients may still occur if donors have NAT-negative IgM-positive results. These findings suggest that clearance of the WNV from solid organs may be delayed compared to its clearance from plasma. Accordingly, screening for WNV among transplant donors is recommended using NAT. There is no evidence to demonstrate the optimal time for solid organ donation in cases of positive NAT, but re-testing after 120 days to confirm negative NAT has become common practice. Patients with negative results after 120 days may donate solid organs.[1]

References

  1. 1.0 1.1 1.2 "Identifying risk factors for West Nile virus (WNV) during evaluation of potential living donors" (PDF). United Network for Organ Sharing. The Organ Procurement and Transplantation Network. 2013. Retrieved 09/11/2014. Check date values in: |accessdate= (help)
  2. Stramer SL, Fang CT, Foster GA, Wagner AG, Brodsky JP, Dodd RY (2005). "West Nile virus among blood donors in the United States, 2003 and 2004". N Engl J Med. 353 (5): 451–9. doi:10.1056/NEJMoa044333. PMID 16079368.
  3. Busch MP, Caglioti S, Robertson EF, McAuley JD, Tobler LH, Kamel H; et al. (2005). "Screening the blood supply for West Nile virus RNA by nucleic acid amplification testing". N Engl J Med. 353 (5): 460–7. doi:10.1056/NEJMoa044029. PMID 16079369.
  4. Kleinman S, Glynn SA, Busch M, Todd D, Powell L, Pietrelli L; et al. (2005). "The 2003 West Nile virus United States epidemic: the America's Blood Centers experience". Transfusion. 45 (4): 469–79. doi:10.1111/j.0041-1132.2005.04315.x. PMID 15819665.


Template:WS