Because the health benefits of breast-feeding are well established, and the risk for WNV transmission through breast-feeding is unknown, these findings do notsuggest a change in breast-feeding recommendations. Lactating women who are ill or who are having difficulty breastfeeding for any reason, as always, are advised to consult their physicians.

Following are questions and answers developed by CDC to assist clinicians who may receive inquiries from their patients regarding WNV and breastfeeding.

Q. Can West Nile virus be transmitted through breast milk?
A. Based on a recent case in Michigan, it appears that West Nile virus can be transmitted through breast milk. A new mother in Michigan contracted West Nile virus from a blood transfusion shortly after giving birth. Laboratory analysis showed evidence of West Nile virus in her breast milk. She breastfed her infant, and three weeks later, her baby's blood tested positive for West Nile virus. Because of the infant's minimal outdoor exposure, it is unlikely that infection was acquired from a mosquito. The infant was most likely infected through breast milk. The child is healthy, and does not have symptoms of West Nile virus.

Q. Should I continue breast-feeding if I am symptomatic for West Nile virus?
A. Because the health benefits of breast-feeding are well established, and the risk for West Nile virus transmission through breast-feeding is unknown, the new findings do not suggest a change in breastfeeding recommendations. The American Academy of Pediatricians and the American Academy of Family Physicians recommend that infants be breastfed for a full year of life.

Lactating women who are ill or who are having difficulty breast-feeding for any reason, as always, should consult their physicians.

Q. Should I continue breast-feeding if I am not symptomatic for West Nile virus?
A. Yes. Because the health benefits of breast-feeding are well established, and the risk for West Nile virus transmission through breast-feeding is unknown, the new findings do not suggest a change in breastfeeding recommendations.

Q. If I am breast-feeding, should I be tested for West Nile virus?
A. No. There is no need to be tested just because you are breast-feeding.

Q. Is there any evidence that West Nile virus is transmitted from mother to child during pregnancy or during birth?
A. There is no evidence that West Nile virus can be transmitted during pregnancy or birth.

Q. Are infants at higher risk than other groups for illness with West Nile virus?
A. No. West Nile virus illnesses in children younger than 1-year-old are infrequent. During 1999-2001, no cases in children younger than one year of age were reported to CDC. Of the over 2500 total West Nile Virus cases in 2002, only four were less than one year of age. We know that one of these infants was not breast-feeding, and investigation of the other infants is underway.

Q. If I am breast-feeding, should I use insect repellent containing DEET?
A. Yes. Insect repellents help people reduce their exposure to mosquito bites that may carry potentially serious viruses such as West Nile virus, and allow them to continue to play and work outdoors. There are no reported adverse events following use of repellents containing DEET in pregnant or breast-feeding women.