In the Amazon, breastfeeding reduced the risk of malaria in children under 2 years old

A study that followed children born between 2015 and 2016 in the city of Cruzeiro do Sul, in Acre, found an association between breastfeeding duration and the risk of infection by the Plasmodium vivax, the parasite that causes malaria. Among 435 children followed up to the second year of life, those who were breastfed for a year or more had a 79.8% lower chance of being infected.

The results, published in the Pediatric Infectious Disease Journal, were obtained as part of the “MINA study —maternal and child in Acre: birth cohort in the western Brazilian Amazon”, carried out with support from FAPESP in the region known as the Juruá Valley, which accounts for 18% of malaria cases in the country.

“In previous work, we saw that the incidence of reported malaria cases was low throughout the first year of life and increased sharply in the second year. We performed serology to identify unreported infections and saw that exposure to Plasmodium vivax was much larger than recorded. In the first year, 77% of the infections were not diagnosed and, in the first two years, at least half of the infections were not diagnosed and, therefore, were not treated with antimalarials”, says Anaclara Pincelli, first author of the study, carried out during her doctorate at Institute of Biomedical Sciences of the University of São Paulo (ICB-USP).

The work was carried out under the guidance of Marcelo Urbano Ferreira, a professor at ICB-USP.

In the first two years of life, 665 children were followed by the study, but it was only possible to collect blood samples from 435. The researchers performed serological tests for three different parasite antigens to identify the children’s exposure to the parasite. Plasmodium vivaxwhich causes malaria when inoculated by mosquito bites.

“Many cases are asymptomatic or have mild symptoms, which means that not everyone seeks medical help and is tested. In addition, the levels of the parasite in the blood may be undetectable by the microscopy test, used to diagnose the infection”, explains Marly Augusto Cardoso, professor at the Faculty of Public Health at the University of São Paulo (FSP-USP) and coordinator of the MINA Study.

The work is the first to relate breastfeeding as a protective factor against Plasmodium vivaxresponsible for 85% of malaria cases in the region.

The few studies that looked into the relationship between breastfeeding and malaria were carried out in sub-Saharan Africa, where another species of the parasite predominates, the Plasmodium falciparumcausing more severe forms of the disease.

protective breast milk

The study also detected that malaria during pregnancy was one of the main factors associated with an increased risk of malaria in the first two years of life.

As this is an endemic region for the disease, the researchers believe that continuous testing, at least in routine appointments, would be a way to better understand the impact of exposure to the disease on children.

In addition, they emphasize the importance of exclusive breastfeeding up to 6 months of life and continued for at least 2 years of age, as recommended by the World Health Organization (WHO). On average, in this population, exclusive breastfeeding occurred only up to the first 16 days of life, when other non-recommended foods were introduced.

“Our idea now is to analyze not only data on malaria up to 5 years of age, but also to verify the impact of the disease on children’s development”, concludes Cardoso.

For presenting her work at the 8th International Conference on Plasmodium vivax Research, which took place in April, Anaclara received an illustration with the results of the study as a prize in the student category.

The article Prolonged Breastfeeding and the Risk of Plasmodium vivax Infection and Clinical Malaria in Early Childhood: A Birth Cohort Study can be read at journals.lww.com/pidj/Citation/2022/10000/Prolonged_Breastfeeding_and_the_Risk_of_Plasmodium.2.aspx.