SD Bioline malaria antigen Pf (HRP-2/pLHD) for assessing efficacy of artemisinin combination therapy against Plasmodium falciparum in pediatric patients in the Democratic Republic of the Congo

Abstract Introduction: The emergence of Plasmodium falciparum resistance to artemisinin combination therapy (ACT) is a worrying development. It call

SD Bioline malaria antigen Pf (HRP-2/pLHD) for assessing efficacy of artemisinin combination therapy against Plasmodium falciparum in pediatric patients in the Democratic Republic of the Congo

Introduction: The emergence of Plasmodium falciparum resistance to artemisinin combination therapy (ACT) is a worrying development. It calls for close surveillance to monitor the efficacy of the drugs. The objectives of this study were to determine the performance of SD Bioline malaria AgPf(HRP-2/pLDH) 3  band Rapid Diagnostic Test (RDT) against Giemsa-stained blood smear and evaluate the suitability of this test in assessing the therapeutic efficacy of ACT in pediatric malaria patients in the Democratic Republic of the Congo (DRC). Methods: Five hundred and one patients with malaria symptoms were screened for P. falciparum in  Kinshasa, DRC. Of the 166 patients who tested positive for P. falciparum at recruitment (day 0), 103 consented to participate in this study and were followed up and retested for P. falciparum on day 3, day 7, day 14, day 21 and day 28. Results: Sensitivity and specificity of the test were significantly high on day 0 and so were their positive and negative predictive values. Higher proportions of false positive cases were observed on the HRP-2 band irrespective of patient parasite densities during the follow up but these were barely seen on the pLDH band. Some patients turned positive during follow up but pLDH readings remained consistent with bloodsmear readings. Conclusion: SD Bioline malaria AgPf(HRP-2/pLDH) RDT demonstrated high performance in DRC. Thus, the test can be employed to assess the efficacy of ACT in pediatric malaria patients and prioritize areas that require the deployment of advanced testing like polymerase chain reaction (PCR).Key words: Malaria, AgPf(HRP-2/pLDH) RDT, artemisinin combination therapy, Democratic Republic of the Cong

Relationships between environmental risk factors, parasitic infections and health outcomes in an urban African setting

The relationships between parasitic infections, environmental and living conditions, and health outcomes were studied in subdivisions of lower (LSES) and higher (HSES) socio-economic status Lubumbashi, Zaire. The two LSES subdivisions had higher prevalences of Plasmodium infection and higher rates of stunting, abdominal pain and low packed cell volume (PCV) than the HSES subdivision. The prevalence and intensity of Ascaris lumbricoides and Trichuris trichiura was not associated with socio-economic status. Maternal education was a significant predictor of A. lumbricoides intensity in both LSES and HSES subdivisions. Factors related to poor sanitation were risk factors for A. lumbricoides in LSES subdivisions, whereas a high ratio of relatives to immediate family members per household predicted high intensity infection in the HSES subdivision. The risk of stunting was higher in children with A. lumbricoides, that of wasting was higher in children with A. lumbricoides or T. trichiura whereas the risk of kwashiorkor was high with T. trichiura but very reduced in those with A. lumbricoides. The four most common clinical conditions were diarrhea, abdominal pain, fever and low PCV. Hookworm infection, T. trichiura infection, young age and residence in LSES subdivisions were determinants of diarrhea. T. trichiura infection, young age and living in a LSES subdivision were risk factors for abdominal pain. Plasmodium infection and young age were associated with fever. LSES was predictive of low PCV. No combination of parasites had antagonistic or synergistic effects on clinical indicators examined. Based on this study, it is suggested that one parasite will increase the risk of infection with another. Although maternal education should be improved in all subdivisions, attention to sanitation, crowding and diet in the LSES subdivisions, and to the role of relatives and visitors in parasite transmission in the HSES subdivision should be priorities

Parasite Specific Antibody Increase Induced by an Episode of Acute P. falciparum Uncomplicated Malaria.

There is no approved vaccine for malaria, and precisely how human antibody responses to malaria parasite components and potential vaccine molecules are developed and maintained remains poorly defined. In this study, antibody anamnestic or memory response elicited by a single episode of P. falciparum infection was investigated.This study involved 362 malaria patients aged between 6 months to 60 years, of whom 19% were early-diagnosed people living with HIV/AIDS (PLWHA). On the day malaria was diagnosed and 42 days later, blood specimens were collected. Parasite density, CD4+ cells, and antibodies specific to synthetic peptides representing antigenic regions of the P. falciparum proteins GLURP, MSP3 and HRPII were measured.On the day of malaria diagnosis, Immunoglobulin (IgG) antibodies against GLURP, MSP3 and HRP II peptides were present in the blood of 75%, 41% and 60% of patients, respectively. 42 days later, the majority of patients had boosted their serum IgG antibody more than 1.2 fold. The increase in level of IgG antibody against the peptides was not affected by parasite density at diagnosis. The median CD4+ cell counts of PLWHAs and HIV negative individuals were not statistically different, and median post-infection increases in anti-peptide IgG were similar in both groups of patients.In the majority (70%) of individuals, an infection of P. falciparum elicits at least 20% increase in level of anti-parasite IgG. This boost in anti-P. falciparum IgG is not affected by parasite density on the day of malaria diagnosis, or by HIV status