West nile virus screening: Difference between revisions

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==Overview==
==Overview==
Universal screening for west nile virus is not recommended. As blood-related transmission of the virus has been reported, blood collection agencies have been screening all donated blood for West Nile virus since 2003 to minimize the risk of transmission. Screening of blood products is done by reverse transcription polymerase chain reaction (RT-PCR) to amplify the viral RNA usually detectable in active infection.
Universal screening for West Nile virus is not recommended. As bloodand transplant-related transmission of the virus has been reported, nucleic acid tests (NAT) may be used to screening for WNV among potential blood and solid organ donors. In blood donation, individual screening is not recommended. 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==
Universal screening for west nile virus is not recommended. Patients who are at risk for the disease and show signs of the disease may be screened. The first-line screening assay for laboratory diagnosis of human WNV infection is the IgM assay. Currently, the FDA has cleared four commercially-available test kits from different manufacturers, for  
===Screening for blood products===
detection of WNV IgM antibodies. Because the IgM and IgG ELISA tests can cross-react between flaviviruses (e.g., dengue, yellow fever), they should be viewed as screening tests only and confirmation with reverse transcription polymerase chain reaction (RT-PCR) is recommended. [http://www.cdc.gov/westnile/resources/pdfs/wnvguidelines.pdf]
Following the discovery of WNV transmission by blood transfusions, WNV blood donor screening is currently performed using nucleic acid testing (NAT). A "minipool" nucleic acid testing program (MP NAT) is currently implemented to detect WNV viremia among donors. 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>
 
 
 
===Screening for solid organ transplantation===
Although the only data on human-to-human transmission by organ transplantation is derived from reports that included decreased 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>


===Screening of blood products===
Following the discovery of WNV transmission by blood products, blood donor screening for WNV has become more common. Blood is currently screened by RT-PCR to amplify the viral RNA. Other screening methods for blood products are not recommended because WNV may only infect recipients if donors are acutely infected. A minipool nucleic acid testing program (MP-NAT) is currently implemented to detect WNV viremia among donors. Patients with positive results 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>


==References==
==References==

Revision as of 01:00, 12 September 2014

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Universal screening for West Nile virus is not recommended. As bloodand transplant-related transmission of the virus has been reported, nucleic acid tests (NAT) may be used to screening for WNV among potential blood and solid organ donors. In blood donation, individual screening is not recommended. 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 for blood products

Following the discovery of WNV transmission by blood transfusions, WNV blood donor screening is currently performed using nucleic acid testing (NAT). A "minipool" nucleic acid testing program (MP NAT) is currently implemented to detect WNV viremia among donors. 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 for solid organ transplantation

Although the only data on human-to-human transmission by organ transplantation is derived from reports that included decreased 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.


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