Dengue Fever: A Potential Risk for Newborns Through Breastfeeding?
Dengue fever, a mosquito-borne illness, can have severe consequences, especially for pregnant women and their newborns. This study sheds light on a critical aspect of dengue transmission and its implications for breastfeeding practices.
What We Know and What This Study Adds
Dengue fever is primarily spread by Aedes mosquitoes, and while many cases are mild, some progress to life-threatening complications. Laboratory tests detect the virus's presence through nucleic acid, antigen, or antibodies in blood samples.
This report focuses on a patient who developed dengue fever just before giving birth. The patient's breast milk, tested within 10 days of symptom onset, showed the presence of dengue virus RNA, NS1 antigen, and IgM antibodies. Interestingly, these markers disappeared by day 22, suggesting a potential window of transmission risk via early breastfeeding.
Implications for Public Health
Breastfeeding should be avoided until at least 22 days post-onset, ensuring that the breast milk is free of viral RNA and IgM antibodies. This period also allows for confirming the infant's health and ruling out any dengue infection. Household members of pregnant women with suspected dengue symptoms should seek immediate medical attention during the dengue season to prevent further transmission.
Study Methodology and Findings
The study analyzed a patient who developed dengue fever a day before delivery. Breast milk samples were collected on days 10, 15, and 22 post-onset. Laboratory tests and whole-genome viral sequencing revealed the presence of dengue virus RNA, NS1 antigen, and IgM in the breast milk within 10 days of symptom onset. By day 15, these markers turned negative, while IgM remained positive until day 22. The viral strain was closely related to a Guangdong isolate, indicating a potential link to local transmission.
Dengue Fever and Its Impact
Dengue fever is an acute infectious disease caused by the dengue virus. While most infections are asymptomatic or mild, some progress to severe complications like dengue hemorrhagic fever and dengue shock syndrome. The subtropical climate of Guangdong Province provides an ideal breeding ground for Aedes mosquitoes, making dengue fever a persistent threat. Since the first reported case in Guangzhou in 1978, the city has become a major epidemic area in China.
Breastfeeding and Dengue Transmission
This study investigated the risk of vertical dengue virus transmission through the breast milk of a pregnant woman who developed dengue fever during late gestation. The patient, a 35-year-old Chinese woman, presented with a fever on November 21, 2024. Her family members had previously been diagnosed with dengue fever. Laboratory tests on the patient's blood and breast milk, as well as the newborn's samples, revealed the presence of dengue virus markers. The patient's breast milk tested positive for dengue virus RNA, NS1 antigen, and IgM within 10 days of symptom onset, but these markers disappeared by day 22.
Implications and Similar Findings
The study's findings suggest a potential risk of vertical transmission of dengue fever through breastfeeding during the period of detectable viral RNA in breast milk. Similar studies have reported the presence of dengue virus nucleic acid in breast milk, raising concerns about neonatal infection. While newborns infected with dengue fever in late gestation may not show severe symptoms, there is still a risk of vertical transmission. The persistence of IgM antibodies in breast milk may pose risks to neonates, as seen in cases of human immunodeficiency viruses, Zika virus, and cytomegalovirus.
Recommendations and Limitations
Based on this study's results, breastfeeding should be cautiously initiated 22 days post-onset, ensuring the absence of viral RNA and IgM in breast milk and confirming the infant's health. However, this study has limitations. The newborn was not breastfed during the study period and tested negative for the virus, so direct evidence of vertical transmission through breastfeeding could not be established. The absence of placental tissue and cord blood samples limited further investigation of transmission mechanisms. Additionally, the generalizability of these findings to a broader population is unclear, and further studies with more comprehensive sample collections are needed.
Conclusion and Takeaways
This study highlights the potential risk of viral transmission during early breastfeeding for patients infected with dengue fever in late gestation. Cautious breastfeeding after ruling out clinical symptoms of dengue infection in both mothers and infants may help prevent viral transmission and poor health outcomes. During dengue season in endemic regions, immediate medical attention and dengue NS1 antigen testing are crucial for pregnant women with suspected symptoms. Future breastfeeding guidelines should consider biomarker testing to ensure the health and safety of both mothers and infants.
