RESUMO
Since its first description by Denis Burkitt, endemic Burkitt's lymphoma (BL), the most common childhood cancer in sub-Saharan Africa, has led scientists to search for clues to the origins of this malignancy. The discovery of Epstein-Barr virus (EBV) in BL cells over 50 years ago led to extensive sero-epidemiology studies and revealed that rather than being a virus restricted to areas where BL is endemic, EBV is ubiquitous in the world's population with an estimated greater than 90% of adults worldwide infected. A second pathogen, Plasmodium falciparum (P. falciparum) malaria is also linked to BL. In this review, we will discuss recent studies that indicate a role for P. falciparum malaria in dysregulating EBV infection, and increasing the risk for BL in children living where P. falciparum malaria transmission is high.
Desde la primera descripción por Denis Burkitt, el linfoma de Burkitt (LB) endémico -el tipo de cáncer pediátrico más común en el África subsahariana- ha guiado a los científicos a investigar este padecimiento en la búsqueda de claves para entender sus orígenes. El descubrimiento desde hace 50 años del virus de Epstein-Barr (VEB) en el LB ha conducido a extensos estudios sero-epidemiológicos y ha revelado que, más que ser un virus restringido a áreas donde el LB es endémico, el VEB es ubicuo en la población mundial, con un estimado mayor del 90% de adultos infectados a escala global. Un segundo agente patógeno se ha ligado al LB, el Plasmodium falciparum (P. falciparum) malaria. En esta revisión se discuten los estudios recientes que indican el papel de P. falciparum malaria en la desregulación de la infección por VEB y en el aumento del riego del LB en niños que viven en regiones con alta transmisión de P. falciparum malaria.
RESUMO
Objectives: Vitamin D may protect against adverse pregnancy outcomes. The prevalence of vitamin D deficiency in pregnant women in sub-Saharan Africa has not been extensively studied and no studies have examined vitamin D status at multiple time points during pregnancy and their association with birth outcomes. Methods: We examined the prevalence of vitamin D deficiency (<50 nmol/L) and insufficiency (<75 nmol/L) in women during pregnancy, and their associations with adverse perinatal outcomes in Kenya. Serum 25-hydroxyvitamin D (25(OH)D) was measured at enrollment and at three additional time points during pregnancy, at delivery, and in cord blood. Binomial and linear regression was used to examine associations between maternal vitamin D status and adverse pregnancy outcomes. Results: A total of 21% of women had vitamin D deficiency and 51% had insufficiency at enrollment. Vitamin D status improved during pregnancy; only 11% had vitamin D deficiency and 32% had insufficiency at delivery. However, 30% and 74% of the cord blood samples had vitamin D deficiency and insufficiency, respectively. Maternal vitamin D concentrations were also associated with significantly higher weight-for-age and weight-for-length Z-scores in the newborns with mean increases of 0.1 and 0.2 per 10 nmol/L serum 25-hydroxyvitamin D, respectively. Further, maternal vitamin D deficiency was associated with a 4-fold increase in the risk of stunting among the neonates (p=0.018). Conclusions: Vitamin D insufficiency is common in pregnant women in Kenya and predicts neonatal birth size. Further research is needed on methods of improving vitamin D status during pregnancy in sub-Saharan Africa.