A survey of malaria among pregnant women in Brazil by researchers from the University of São Paulo (USP) has been published in Lancet Regional Health – Americas. According to the researchers, the study is the first to provide insight into autochthonous malaria in pregnancy in terms of spatial and temporal trends.
The results show that although malaria during pregnancy still represents a major public health problem in the northern region of Brazil, and in particular in the Amazon, the number of cases has halved during the period analyzed (2004-18 ). The reduction is due to the expansion of the health service network that provides diagnosis and treatment, according to the researchers, as well as the inclusion of artemisinin in the treatment regimen from 2006.
They also believe that the fall could have been even greater had it not been for the decentralization of public action in the fight against malaria throughout the territory, due to the autonomy granted to local authorities in this area, so that the municipal healthcare teams change with each new election.
“Several studies on malaria in pregnancy in Brazil have been published, but none present a comprehensive investigation of the disease, and most were conducted in specific locations or regions. This is why we set out to study the spatial and temporal patterns of malaria during pregnancy in Brazil and to epidemiologically characterize the population,” Claudio Romero Farias Marinho, last author of the article, told Agência FAPESP. Marinho is a professor at the Institute of Biomedical Sciences (ICB-USP) and head of its experimental immunoparasitology laboratory.
High risk group
Pregnant women are one of the high-risk groups for malaria, Marinho noted. The disease is caused by protozoan parasites of the genus Plasmodium transmitted by Anopheles mosquitoes. Pregnant women with malaria are at risk of severe anemia, premature delivery, miscarriage and stillbirth. The fetus may have microcephaly or intrauterine growth retardation and impaired development 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 respiratory problems in early childhood and increased susceptibility to infections, as well as an increased risk of developing chronic diseases such as diabetes and hypertension in adulthood,” Marinho said. .
These were the reasons for focusing on malaria in pregnancy in the survey conducted by Jamille DombrowskiPhD student at ICB-USP with a stock Exchange of FAPESP, in partnership with researchers from the School of Public Health (FSP-USP). The group analyzed data from 61,833 pregnant women with malaria extracted from the Ministry of Health’s epidemiological surveillance system (SIVEP-Malaria) over a 15-year period between 2004 and 2018.
The results highlighted a high incidence of malaria during pregnancy in the municipalities of Acre, Amazonas, Rondônia and Pará, all states in the northern region of Brazil. Younger women were most at risk, especially those aged 15 to 24, as the largest proportion of primigravid women (having their first pregnancy) are in this age group. Specific immunity against forms of Plasmodium inhabiting the placenta is acquired after several pregnancies and is therefore lower in primigravidae.
“It is important to note that northern primigravidae are very young and have had less exposure to the parasite, so the organism has less protection against it,” Marinho said.
The study also found evidence that the treatment regimen for these patients may not be correct, given the high percentage of primaquine reported. The drug is contraindicated during pregnancy, as it crosses the placenta and can destroy the red blood vessels of the fetus, impairing oxygen transport and possibly causing miscarriage.
The findings of the survey conducted by Marinho and his group can help the Ministry of Health formulate public policy to fight malaria and provide better care for pregnant women with the disease. It will be possible to identify areas requiring further surveillance or additional interventions, including specific strategies to protect pregnant women and their babies from the devastating consequences of malaria.
After having drawn up a complete epidemiological portrait, the researchers are now concentrating on the early diagnosis of a complication called placental malaria, characterized by an accumulation of Plasmodium– infected red blood cells in placenta and fetal membrane. This can only be detected after the baby is born, so intervention or treatment is not possible.
Dombrowski is working on a new project to identify biomarkers that can be measured quickly and inexpensively, so that their analysis can be introduced into prenatal routines.
About the São Paulo Research Foundation (FAPESP)
The São Paulo Research Foundation (FAPESP) is a public institution whose mission is to support scientific research in all areas of knowledge by granting scholarships, fellowships and grants to researchers linked to educational institutions University and Research Institute of the State of São Paulo, Brazil. FAPESP is aware that the best research can only be done by working with the best researchers at the international level. Therefore, it has partnered with funding agencies, higher education institutions, private companies and research organizations in other countries known for the quality of their research and has encouraged scientists funded by its grants to further develop their international collaboration. You can find out more about FAPESP at www.fapesp.br/en and visit the FAPESP news agency at www.agencia.fapesp.br/en to keep up to date with the latest scientific advances that FAPESP is helping to achieve through to its many programs, awards and research centers. You can also subscribe to the FAPESP press agency at http://agencia.fapesp.br/subscribe
The Lancet Regional Health – Americas
The title of the article
Mapping and characterizing areas with high levels of malaria during pregnancy in Brazil: a spatio-temporal analysis
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