A survey of malaria among pregnant women in Brazil by researchers from the University of São Paulo (USP) was published in Lancet Regional Health—American. According to the researchers, the study is the first to provide insight into indigenous malaria in pregnancy in terms of spatial and temporal trends.
The findings show that although malaria pregnancy is still a serious public health problem in the northern region of Brazil, and especially in the Amazon, the number of cases has halved during the analyzed period (2004-18). The reduction was due to the expansion of the network of medical services that provide diagnosis and treatment, according to the researchers, as well as the inclusion of artemisinin in the therapeutic scheme since 2006.
They also believe that the decline could have been even greater had it not been for the decentralization of public malaria control across the country due to the autonomy given to local authorities in this area, so that municipal health teams change with each new election.
“Several studies of malaria in pregnancy in Brazil have been published, but none of them provide a comprehensive overview of the disease, and most of them were conducted in specific locations or regions. That’s why we decided to investigate the spatial and temporal patterns of malaria during pregnancy in Brazil, and to epidemiologically characterize the population,” said Claudio Romero Farias Marinho, last author of the paper, Agência FAPESP. Marinho is a professor at the Institute of Biomedical Sciences (ICB-USP) and head his experimental immunoparasitological laboratory.
High risk group
Pregnant women are one of the high risk groups from malaria, said Mourinho. The disease is caused by protozoan parasites of the genus Plasmodium, which are transmitted by Anopheles mosquitoes. Pregnant women with malaria are at risk of severe anemia, premature birth, miscarriage, and stillbirth. The fetus may have microcephaly or intrauterine growth retardation and developmental disorders after birth.
“Studies have shown that malaria affects brain development and function, causing cognitive and neurological deficits that can lead to cerebral palsy and epilepsy. It is also associated with breathing problems in infancy and increased susceptibility to infections, as well as an increased risk of developing chronic diseases such as diabetes and hypertension in adulthood,” said Mourinho.
These were the reasons for focusing on malaria in pregnancy in a survey conducted by Jamil Dombrowski, Ph.D. candidate at ICB-USP with a FAPESP scholarship in partnership with researchers from the School of Public Health (FSP-USP). The team analyzed data for 61,833 people pregnant women with malaria extracted from the system of epidemiological surveillance of the Ministry of Health (SIVEP-Malaria) for a 15-year period between 2004 and 2018.
The results showed a high incidence of malaria during pregnancy in the municipalities of Accra, Amazonas, Randonia and Paro, all states in the northern region of Brazil. Younger women, especially those aged 15 to 24, were at greatest risk, as this age group accounts for the highest proportion of primiparous (first-time) women. Specific immunity against forms of Plasmodium that live in the placenta is acquired after several pregnancies and is therefore lower in first-time pregnant women.
“It is important to note that the progenitors in the north are very young and have been less exposed to the parasite, so the body has less protection against it,” Marinho said.
The study also found evidence that the therapeutic regimen for these patients may be incorrect, given the high percentage of reported attrition. The drug is contraindicated during pregnancy, as it crosses the placenta and can destroy the red blood vessels in the fetus, impairing oxygen transport and potentially causing miscarriage.
The results of the survey Marinho and his group can help the Ministry of Health to formulate state policy control malaria and offer better care to pregnant women with the disease. It will be possible to identify areas that require more surveillance or additional interventions, including specific strategies to protect pregnant women and their babies from the devastating effects of malaria.
Having created a complete epidemiological portrait, researchers are now focusing on the early diagnosis of a complication known as placental malaria, which is characterized by the accumulation of Plasmodium-infected red blood cells in the placenta and amniotic membranes. It can only be detected after the baby is born, so no intervention or treatment is possible.
Dombrowski is working on a new project to identify biomarkers that can be measured quickly and affordably so that their analysis can be incorporated into prenatal procedures.
Antibodies help identify women protected from placental malaria
Additional information:
Jamil Gregorio Dombrovsky and others. Mapping and characterization of areas with high rates of malaria during pregnancy in Brazil: a spatiotemporal analysis, The Lancet Regional Health—America (2022). DOI: 10.1016/j.lana.2022.100285
Citation: Researchers map malaria incidence during pregnancy in Brazil (2022, August 16) Retrieved August 16, 2022, from https://medicalxpress.com/news/2022-08-incidence-malaria-pregnancy-brazil.html
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