Last update Oct. 31, 2020

Maternal West Nile Fever (WNF)

Very Low Risk

Safe. Compatible. Minimal risk for breastfeeding and infant.

Infection caused by the Western Nile Virus (WNV), which is an flavivirus transmitted by mosquito bite.
Reservoir: birds. Vector: mosquitoes from the genus Culex. Host: horses and humans.
The disease has an incubation period from 5 to 15 days and usually appears asymptomatic (80% of cases) or with mild flu symptoms. Less than 1% of affected patients develop meningoencephalitis and other serious features. (AAP 2018, p888).

There has been a possible documented case of transmission through breastfeeding (positive RNA and specific IgM antibodies in the milk with positive plasma IgM antibody in the infant), but the child remained asymptomatic (CDC 2002).

Among six breastfed infants whose mothers were diagnosed as positively infected, who subsequently had serologic tests for West Nile virus that were negative, only one of them exhibited a slight skin rash (Hinckley 2007).

Because the health advantages of breast feeding are considered greater than the potential risk of transmission, experts and expert committees recommend breastfeeding even in areas where there is the presence of Zika virus recommends that mothers with possible or confirmed WNV infection or exposure continue to breast feed, even from endemic areas (AAP 2018 p119, Lawrence 2016 p469 & 790, Hayes 2005).

Suggestions made at e-lactancia are done by APILAM team of health professionals, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it. The pharmaceutical industry contraindicates breastfeeding, mistakenly and without scientific reasons, in most of the drug data sheets.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

Your contribution is essential for this service to continue to exist. We need the generosity of people like you who believe in the benefits of breastfeeding.

Thank you for helping to protect and promote breastfeeding.

José María Paricio, founder of e-lactancia.

Other names

Maternal West Nile Fever (WNF) is also known as


Maternal West Nile Fever (WNF) belongs to this group or family:


  1. Van de Perre P, Molès JP, Nagot N, Tuaillon E, Ceccaldi PE, Goga A, Prendergast AJ, Rollins N. Revisiting Koch's postulate to determine the plausibility of viral transmission by human milk. Pediatr Allergy Immunol. 2021 Jul;32(5):835-842. Abstract Full text (link to original source)
  2. AAP. American Academy of Pediatrics. Red Book: 2018–2021. Report of the Committee on Infectious Diseases. American Academy of Pediatrics. Kimberlin DW, Brady MT, Jackson MA Long SS, eds. Red Book: 2018–2021 Report of the Committee on Infectious Diseases. 31st ed. Itasca, IL: American Academy of Pediatrics; 2018.
  3. Lawrence RA, Lawrence RM. Breastfeeding. A guide for the medical profession. Eighth Edition. Philadelphia: Elsevier; 2016
  4. Garcia-Loygorri MC, De Luis D, Torreblanca B, March GA, Bachiller MR, Eiros JM. La leche materna como vehículo de transmisión de virus. [Beast Milk as vehicle of transmission of virus]. Nutr Hosp. 2015 Abstract Full text (link to original source) Full text (in our servers)
  5. Lawrence RM. Circumstances when breastfeeding is contraindicated. Pediatr Clin North Am. 2013 Feb;60(1):295-318. Abstract
  6. Hinckley AF, O'Leary DR, Hayes EB. Transmission of West Nile virus through human breast milk seems to be rare. Pediatrics. 2007 Abstract
  7. Hayes EB, Komar N, Nasci RS, Montgomery SP, O'Leary DR, Campbell GL. Epidemiology and transmission dynamics of West Nile virus disease. Emerg Infect Dis. 2005 Abstract Full text (link to original source) Full text (in our servers)
  8. Hayes EB, O'Leary DR. West Nile virus infection: a pediatric perspective. Pediatrics. 2004 Abstract
  9. Centers for Disease Control and Prevention (CDC). Possible West Nile virus transmission to an infant through breast-feeding--Michigan, 2002. MMWR Morb Mortal Wkly Rep. 2002 Abstract Full text (link to original source) Full text (in our servers)

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