Justice Sylverken

Genome-wide association study indicates two novel resistance loci for severe malaria

Malaria causes approximately one million fatalities per year, mostly among African children. Although highlighted by the strong protective effect of the sickle-cell trait, the full impact of human genetics on resistance to the disease remains largely unexplored. Genome-wide association (GWA) studies are designed to unravel relevant genetic variants comprehensively; however, in malaria, as in other infectious diseases, these studies have been only partly successful. Here we identify two previously unknown loci associated with severe falciparum malaria in patients and controls from Ghana, West Africa. We applied the GWA approach to the diverse clinical syndromes of severe falciparum malaria, thereby targeting human genetic variants influencing any step in the complex pathogenesis of the disease. One of the loci was identified on chromosome 1q32 within the ATP2B4 gene, which encodes the main calcium pump of erythrocytes, the host cells of the pathogenic stage of malaria parasites. The second was indicated by an intergenic single nucleotide polymorphism on chromosome 16q22.2, possibly linked to a neighbouring gene encoding the tight-junction protein MARVELD3. The protein is expressed on endothelial cells and might therefore have a role in microvascular damage caused by endothelial adherence of parasitized erythrocytes. We also confirmed previous reports on protective effects of the sickle-cell trait and blood group O. Our findings underline the potential of the GWA approach to provide candidates for the development of control measures against infectious diseases in humans.

Randomized controlled trial of RTS,S/AS02D and RTS,S/AS01E malaria candidate vaccines given according to different schedules in Ghanaian children

Background The target delivery channel of RTS,S candidate malaria vaccines in malaria-endemic countries in Africa is the World Health Organisation Expanded Program on Immunization. As an Adjuvant System, age de-escalation and schedule selection step, this study assessed 3 schedules of RTS,S/AS01E and RTS,S/AS02D in infants and young children 5–17 months of age in Ghana. Methodology A Phase II, partially-blind randomized controlled study (blind to vaccine, not to schedule), of 19 months duration was conducted in two (2) centres in Ghana between August 2006 and May 2008. Subjects were allocated randomly (1∶1∶1∶1∶1∶1) to one of six study groups at each study site, each defining which vaccine should be given and by which schedule (0,1-, 0,1,2- or 0,1,7-months). For the 0,1,2-month schedule participants received RTS,S/AS01E or rabies vaccine at one center and RTS,S/AS01E or RTS,S/AS02D at the other. For the other schedules at both study sites, they received RTS,S/AS01E or RTS,S/AS02D. The primary outcome measure was the occurrence of serious adverse events until 10 months post dose 1. Results The number of serious adverse events reported across groups was balanced. One child had a simple febrile convulsion, which evolved favourably without sequelae, considered to be related to RTS,S/AS01E vaccination. Low grade reactions occurred slightly more frequently in recipients of RTS,S/AS than rabies vaccines; grade 3 reactions were infrequent. Less local reactogenicity occurred with RTS,S/AS01E than RTS,S/AS02D. Both candidate vaccines were highly immunogenic for anti-circumsporozoite and anti-Hepatitis B Virus surface antigen antibodies. Recipients of RTS,S/AS01E compared to RTS,S/AS02D had higher peak anti-circumsporozoite antibody responses for all 3 schedules. Three dose schedules were more immunogenic than 2 dose schedules. Area under the curve analyses for anti-circumsporozoite antibodies were comparable between the 0,1,2- and 0,1,7-month RTS,S/AS01E schedules. Conclusions Both candidate malaria vaccines were well tolerated. Anti-circumsporozoite responses were greater with RTS,S/AS01E than RTS,S/AS02D and when 3 rather than 2 doses were given. This study supports the selection of RTS,S/AS01E and a 3 dose schedule for further development in children and infants. Trial Registration ClinicalTrials.gov NCT00360230

Exploring the relationship between chronic undernutrition and asymptomatic malaria in Ghanaian children.

BackgroundA moderate association has been found between asymptomatic parasitaemia and undernutrition. However, additional investigation using the gold standard for asymptomatic parasitaemia confirmation, polymerase chain reaction (PCR), is needed to validate this association. Anthropometric measurements and blood samples from children less than five years of age in a rural Ghanaian community were used to determine if an association exists between chronic undernutrition and PCR-confirmed cases of asymptomatic malaria.MethodsThis was a descriptive cross-sectional study of 214 children less than five years of age from a community near Kumasi, Ghana. Blood samples and anthropometric measurements from these children were collected during physical examinations conducted in January 2007 by partners of the Barekuma Collaborative Community Development Programme.ResultsFindings from the logistic model predicting the odds of asymptomatic malaria indicate that children who experienced mild, moderate or severe stunting were not more likely to have asymptomatic malaria than children who were not stunted. Children experiencing anaemia had an increased likelihood (OR = 4.15; 95% CI: 1.92, 8.98) of asymptomatic malaria. Similarly, increased spleen size, which was measured by ultrasound, was also associated with asymptomatic malaria (OR = 2.17; 95% CI: 1.44, 3.28). Fast breathing, sex of the child, and age of the child were not significantly associated with the asymptomatic malaria.ConclusionsNo significant association between chronic undernutrition and presence of asymptomatic malaria was found. Children who experience anaemia and children who have splenomegaly are more likely to present asymptomatic malaria. Programmes aimed at addressing malaria should continue to include nutritional components, especially components that address anaemia.

Delayed hemolysis after treatment with parenteral artesunate in African children with severe malaria--a double-center prospective study.

BACKGROUND Parenteral artesunate is recommended as first-line therapy for severe malaria. While its efficacy is firmly established, data on safety are still incomplete. Delayed hemolysis has been described in hyperparasitemic nonimmune travelers, but it is unknown if African children are equally at risk. METHODS Children aged 6 to 120 months with severe malaria were followed up after treatment with parenteral artesunate in Lambaréné, Gabon, and Kumasi, Ghana. The primary outcome was incidence of delayed hemolysis on day 14. RESULTS In total, 72 children contributed complete data sets necessary for primary outcome assessment. Delayed hemolysis was detected in 5 children (7%), with 1 child reaching a nadir in hemoglobin of 2.8 g/dL. Patients with delayed hemolysis had higher parasite counts on admission (geometric mean parasite densities (GMPD) 306 968/µL vs 92 642/µL, P = .028) and were younger (median age: 24 months vs 43 months, P = .046) than the rest of the cohort. No correlation with sickle cell trait or glucose-6-phosphate-dehydrogenase deficiency was observed. CONCLUSIONS Delayed hemolysis is a frequent and relevant complication in hyperparasitemic African children treated with parenteral artesunate for severe malaria. Physicians should be aware of this complication and consider prolonged follow-up. CLINICAL TRIALS REGISTRATION Pan-African Clinical Trials Registry: PACTR201102000277177 (www.pactr.org).

T Cell Responses to the RTS,S/AS01E and RTS,S/AS02D Malaria Candidate Vaccines Administered According to Different Schedules to Ghanaian Children

Background The Plasmodium falciparum pre-erythrocytic stage candidate vaccine RTS,S is being developed for protection of young children against malaria in sub-Saharan Africa. RTS,S formulated with the liposome based adjuvant AS01E or the oil-in-water based adjuvant AS02D induces P. falciparum circumsporozoite (CSP) antigen-specific antibody and T cell responses which have been associated with protection in the experimental malaria challenge model in adults. Methods This study was designed to evaluate the safety and immunogenicity induced over a 19 month period by three vaccination schedules (0,1-, 0,1,2- and 0,1,7-month) of RTS,S/AS01E and RTS,S/AS02D in children aged 5–17 months in two research centers in Ghana. Control Rabies vaccine using the 0,1,2-month schedule was used in one of two study sites. Results Whole blood antigen stimulation followed by intra-cellular cytokine staining showed RTS,S/AS01E induced CSP specific CD4 T cells producing IL-2, TNF-α, and IFN-γ. Higher T cell responses were induced by a 0,1,7-month immunization schedule as compared with a 0,1- or 0,1,2-month schedule. RTS,S/AS01E induced higher CD4 T cell responses as compared to RTS,S/AS02D when given on a 0,1,7-month schedule. Conclusions These findings support further Phase III evaluation of RTS,S/AS01E. The role of immune effectors and immunization schedules on vaccine protection are currently under evaluation. Trial Registration ClinicalTrials.gov NCT00360230

Continuous positive airway pressure for children with undifferentiated respiratory distress in Ghana: an open-label, cluster, crossover trial

BACKGROUND In low-income and middle-income countries, invasive mechanical ventilation is often not available for children at risk of death from respiratory failure. We aimed to determine if continuous positive airway pressure (CPAP), a form of non-invasive ventilation, decreases all-cause mortality in children with undifferentiated respiratory distress in Ghana. METHODS This open-label, cluster, crossover trial was done in two Ghanaian non-tertiary hospitals where invasive mechanical ventilation is not routinely available. Eligible participants were children aged from 1 month to 5 years with a respiratory rate of more than 50 breaths per min in children 1-12 months old, or more than 40 breaths per min in children older than 12 months, and use of accessory muscles or nasal flaring. CPAP machines were allocated to one hospital during each study block, while the other hospital served as the control site. The initial intervention site was randomly chosen using a coin toss. 5 cm of water pressure was delivered via CPAP nasal prongs. The primary outcome measure was all-cause mortality rate at 2 weeks after enrolment in patients for whom data were available after 2 weeks. We also did post-hoc regression analysis and subgroup analysis of children by malaria status, oxygen saturation, and age. This study is registered with ClinicalTrials.gov, number NCT01839474. FINDINGS Between Jan 20, 2014, and Dec 5, 2015, 2200 children were enrolled: 1025 at the intervention site and 1175 at the control site. Final analysis included 1021 patients in the CPAP group and 1160 patients in the control group. 2 weeks after enrolment, 26 (3%) of 1021 patients in the CPAP group, and 44 (4%) of 1160 patients in the control group, had died (relative risk [RR] of mortality 0·67, 95% CI 0·42-1·08; p=0·11). In children younger than 1 year, all-cause mortality was ten (3%) of 374 patients in the CPAP group, and 24 (7%) of 359 patients in the control group (RR 0·40, 0·19-0·82; p=0·01). After adjustment for study site, time, and clinically important variables, the odds ratio for 2-week mortality in the CPAP group versus the control group was 0·4 in children aged up to 6 months, 0·5 for children aged 12 months, 0·7 for children aged 24 months, and 1·0 for those aged 36 months. 28 patients (3%) in the CPAP group and 24 patients (2%) in the control group had CPAP-related adverse events, such as vomiting, aspiration, and nasal, skin, or eye trauma. No serious adverse events were observed. INTERPRETATION In the unadjusted analysis the use of CPAP did not decrease all-cause 2-week mortality in children 1 month to 5 years of age with undifferentiated respiratory distress. After adjustment for study site, time, and clinically important variables, 2-week mortality in the CPAP group versus the control group was significantly decreased in children 1 year of age and younger. CPAP is safe and improves respiratory rate in a non-tertiary setting in a lower-middle-income country. FUNDING General Electric Foundation.

Role of Diagnostic Testing in Schistosomiasis Control Programs in Rural Ghana

Background: Schistosomiasis affects an estimated 200-300 million people worldwide. Construction of dams has contributed to the high prevalence of urinary schistosomiasis in Ghana. To assist rural villages downstream from the Barekese dam in schistosomiasis control programs, this study evaluated possible detection methods of schistosomiasis. Methods: A cross-sectional survey of volunteers was conducted in a rural setting of Ghana. Five hundred and thirty four (534) volunteers provided symptom information and urine samples for urinalysis. Microscopic egg count of 341 random samples was used to determine prevalence of disease and to analyze effectiveness of urinalysis and symptom information for diagnosing schistosomiasis. Results: Schistosomiasis prevalence was 41.1 % for the village. The highest prevalence was in the 10-14 age groups (71.1 %). Sensitivity and specificity for hematuria was 76.1 and 77.7 % respectively, and proteinuria was 58.2 & 68.7 % respectively. The positive predictive value was highest for hematuria (71.1 %). The highest negative predictive value was among positive proteinuria or hematuria (84.0 %). From urinary symptom information, reporting pain and dark urine yielded the highest positive predictive value (72.0 %). Reporting pain, difficulty, or dark urine yielded the highest negative predictive value (75.8 %). Discussion: The positive and negative predictive values of urine analysis and symptom information may be an inexpensive tool for diagnosing schistosomiasis in areas of high prevalence.

Aetiology of viral hepatitis among jaundiced patients presenting to a tertiary hospital in Ghana

Background Viral hepatitis continues to play significant role in causing morbidity and mortality in sub-Saharan Africa. Apart from the few population based studies available, not many have investigated the burden of these viruses in jaundiced patients. Among the few studies, hepatitis E is the least studied among jaundiced patients. This study was aimed at describing the frequency, distribution and risk of the different hepatitis viruses among jaundiced patients reporting to the second largest teaching hospital in Ghana. Methods From November, 2015 to April, 2016, a cross-sectional study was conducted among jaundiced patients attending the Komfo Anokye Teaching Hospital. Between 3–5 ml of blood was collected from each patient and screened for viral hepatitis agents using both serologic and molecular-based assays. Results In the 155 patients recruited, hepatitis B was the most prevalent [54.2% (95% CI = 46.0%–62.2%)] followed by hepatitis E [32.9% (95% CI = 25.6–40.9%)]. Most cases of hepatitis E occurred as co-infections with hepatitis B (18%), with the predominant clinical feature being hepatocellular carcinoma. Risk factor variable analysis showed middle and older aged individuals were more at risk of hepatitis B exposure whereas younger age groups (<18 years) were more at risk of hepatitis E virus infection. Conclusion Hepatitis viruses are still important in the viral aetiology of jaundice in Ghana. Hepatitis B and hepatitis E co-infections could play significant roles in causing severe disease. A more aggressive approach needs to be adopted in order to reduce the morbidity and mortality associated with hepatitis causing viruses in Ghana and other developing countries.

Respiratory Pathogens in Children 1 Month to 5 Years of Age Presenting With Undifferentiated Acute Respiratory Distress in 2 District-Level Hospitals in Ghana

Abstract Ghanaian children (2176) aged <5 years who presented with undifferentiated acute respiratory distress were tested for respiratory pathogens using a BioFire FilmArray polymerase chain reaction assay. Rhinovirus and/or enterovirus was detected in 36% of the assays, respiratory syncytial virus in 11%, and parainfluenza in 7%. Respiratory syncytial virus and metapneumovirus were detected more frequently in the rainy season than in the dry season.