Sickle cell trait (HbAS) and stunting in children below two years of age in an area of high malaria transmission

<p>Abstract</p> <p>Background</p> <p>While the protective effects of sickle cell trait (HbAS) against severe malaria and the resulting survival advantage are well known, the impact on the physical development in young children remains unclear. This study was aimed to investigate the relationship between HbS carriage and stunting in children below two years of age in a cohort from the Ashanti Region, Ghana.</p> <p>Methods</p> <p>1,070 children were recruited at three months of age and followed-up for 21 months with anthropometric measurements performed every three months. Incidence rate ratios with 95% confidence intervals were calculated by Poisson regression to estimate the association of β-globin genotypes with the number of malaria episodes. Odds ratios (OR) were calculated for the association between the occurrence of β-globin genotypes and/or malaria episodes and stunting. The age-dependent between-group and within-group effects for the β-globin genotypes were assessed by population-averaged models estimated by generalized estimation equation with autoregressive correlation structure.</p> <p>Results</p> <p>Analyses showed a significantly lower age-dependent risk of stunting (OR 0.56; 95% CI 0.33–0.96) in carriers of the HbAS genotype (n = 102) in comparison to those with HbAA (n = 692). This effect was restricted to children who experienced malaria episodes during the observation period suggesting that the beneficial effect of the β-globin HbS variant on the incidence of stunting is closely linked to its protection from mild malaria episodes.</p> <p>Conclusion</p> <p>The lower risk of chronic malnutrition in early childhood, mediated by protection against mild malaria episodes, may contribute to the survival advantage of HbAS carriers in areas of high malaria transmission.</p

Diagnosing Schistosomiasis by Detection of Cell-Free Parasite DNA in Human Plasma

Bilharzia (schistosomiasis) occurs in the tropics and subtropics and is one of the most important parasite diseases of humans. It is caused by flukes residing in the vessels of the gut or bladder, causing fever, pain, and bleeding. Bladder cancer or esophageal varices may follow. Diagnosis is difficult, requiring detection of parasite eggs in stool, urine, or gut/bladder biopsies. In this paper, we introduce a fundamentally new way of diagnosing bilharzia from the blood. It has been known for almost 20 years that patients with cancer have tumor-derived DNA circulating in their blood, which can be used for diagnostic purposes. During pregnancy, free DNA from the fetus can be detected in motherly blood, which can be used for diagnosing a range of fetal diseases and pregnancy-associated complications. We found that parasite DNA can be detected in the same way in the blood of patients with bilharzia. In patients with early disease, diagnosis was possible earlier than with any other test. DNA could be detected in all patients with active disease in our study. Patients after treatment had significantly lower parasite DNA concentrations and turned negative 1–2 years after treatment. Future studies should implement the method in large cohorts of patients and should define criteria for the confirmation of the success of treatment by comparing the concentration of fluke DNA before and after therapy

Eosinophilia in Returning Travelers and Migrants

INTRODUCTION: Eosinophilia in travelers returning from tropical countries is often caused by helminths. The high eosinophil counts arise particularly from tissue migration of invasive larvae. METHODS: Review of literature selected by means of a Medline search using the MeSH terms "eosinophilia" and "helminth." RESULTS: The patient’s geographic and alimentary history may suggest infection with particular parasitic worms. A targeted diagnostic approach is suggested. The physician should concentrate on the principal signs and be guided by the geographic and alimentary history. Elaborate diagnostic measures are seldom indicated. DISCUSSION: Although eosinophilia alone has low positive predictive value for a worm infection, it points clearly to helminthosis if the patient has recently returned from the tropics and the eosinophilia is new