Ebola Virus May Be Transmitted Through Breast Milk

A case study recently published in Emerging Infectious Diseases adds to a small, but disturbing collection of reports describing the transmission of Ebola virus from mother to child through breastfeeding.

Although Ebola virus infection is associated with a high mortality rate, there are those who survive infection and seem to have the virus cleared from their blood. However, this population may be at risk for transmitting the virus to others through the exchange of bodily fluids other than blood. For example, the World Health Organization (WHO) recommends testing semen for the presence of Ebola virus in male Ebola virus disease survivors.¹

Helena Nordenstedt, MD, an assistant professor in the Department of Public Health Sciences at the Karolinska Institutet in Stockholm, Sweden and the first author on the published study, described a case involving an Ebola virus-positive mother residing in Guinea and her twin infants.

The case was first noted in 2015. Both the mother and her exclusively breastfed 4-month-old twins, referred to in the report as baby 1 and baby 2, were registered as contacts, following a postmortem diagnosis of Ebola virus infection in the woman’s mother. After becoming registered, the mother and her twins were followed daily by contact tracers. Baby 1 experienced a sudden onset fever, died a few days later, and was buried without being tested for Ebola virus. Nordenstedt and colleagues stated that, "... according to the WHO case definition, baby 1 was a probable EVD case-patient."²

Shortly thereafter, the mother began to show clinical signs and symptoms of Ebola virus infection and was hospitalized. Although she was diagnosed as Ebola virus-positive, her disease course and prognosis were good and she recovered, testing negative for Ebola virus in both blood and urine roughly one month later. Baby 2 tested negative for Ebola virus at all time points.

On three occasions during her hospital stay, the mother's breast milk tested positive for Ebola virus, yet baby 2 never tested positive for Ebola virus infection. This finding prompted Nordenstedt et al to state that, "Many questions in this case remain unanswered, but our findings show the potential infectivity of breast milk for at least 26 days after EVD symptom onset and demonstrate a case in which a baby was not infected by breast milk from his EBOV-positive mother. However, it should be noted that the woman’s breast milk was never tested while she was breastfeeding baby 2."

The case reported by Nordenstedt et al adds to a very small, but suggestive, literature on the transmission of Ebola virus from mothers to infants via breastfeeding. In the 2000 outbreak in Uganda, a single case of Ebola virus infection was detected in the breast milk of a convalescent-phase patient 15 days after symptom onset.³ More recently, during the current outbreak, a mother—baby pair in Guinea both tested positive for the Ebola virus. The baby demonstrated Ebola virus disease 14 days after symptom onset in the mother; however, the mother's breast milk was Ebola virus-negative when sampled 17 days after her symptom onset.⁴

In light of their case study findings, Nordenstedt and colleagues stated, "Considering the high EVD death rate, until further evidence is found, we recommend that Ebola virus-positive women stop breastfeeding immediately and that breastfeeding not be resumed until 2 negative RT-PCR tests of the breast milk have been confirmed." Additionally, Nordenstedt et al recommended that, "The public health risk for EBOV to remain in breast milk for at least 26 days after EVD symptom onset and for breast milk to possibly be infectious after a patient has cleared the virus from the blood should also be acknowledged."

Collectively, the data from this case and the two previously reported cases should prompt serious consideration of breastfeeding cessation and milk testing in all lactating Ebola virus-positive mothers. These measures would be somewhat similar to the recommendations made by the WHO for the testing of male bodily fluids other than blood (i.e., semen).¹

William Perlman, PhD, CMPP is a former research scientist currently working as a medical/scientific content development specialist. He earned his BA in Psychology from Johns Hopkins University, his PhD in Neuroscience at UCLA, and completed three years of postdoctoral fellowship in the Neuropathology Section of the Clinical Brain Disorders Branch of the National Institute of Mental Health.

References

1. World Health Organization. Sexual and reproductive health. Interim advice on the sexual transmission of the Ebola virus disease. 2015 May 8 [cited 2016 Mar 31]. http://www.who.int/reproductivehealth/topics/rtis/ebola-virus-semen/en/
2. World Health Organization. Interim guideline: case definition recommendations for Ebola or Marburg virus diseases. 2014 Aug 9 [cited 2016 Mar 31]. http://apps.who.int/iris/bitstream/10665/146397/1/WHO_EVD_CaseDef_14.1_eng.pdf?ua=1.
3. Bausch DG, Towner JS, Dowell SF, et al. Assessment of the risk of Ebola virus transmission from bodily fluids and fomites. J Infect Dis 2007;196(Suppl 2):S142—7.
4. Moreau M, Spencer C, Gozalbes JG, et al. Lactating mothers infected with Ebola virus: EBOV RT-PCR of blood only may be insufficient. Euro Surveill 2015;20. pii: 21017.