Acquisition of naturally acquired antibody response to Plasmodium falciparum erythrocyte membrane protein 1-DBLα and differential regulation of IgG subclasses in severe and uncomplicated malaria

Objectives: To explore whether individuals infected with Plasmodium falciparum(P. falciparum) develop antibodies directed against Pf EMP1-DBLa, and to assess their IgG subclass distribution in severe and uncomplicated malaria.Methods: The anti-PfDBLα IgG and their IgG subclass distributions in plasma of severe(SM) and uncomplicated malaria(UCM) were assessed by enzyme-linked immunoabsorbent assay. The antibody profiles to P. falciparum blood stage antigens were evaluated. CD36 binding ability was determined by static receptor-binding assays.Rosette formation was performed by staining with acridine orange.Results: Significantly higher number of UCM(86.48%) than SM(57.78%) plasma contained total acquisition of specific IgG to P. falciparum antigens(P = 0.000). Similar manners were seen in response to P. falciparum DBLa with significant difference(UCM,59.46% vs SM, 40.00%; P = 0.014). Anti-PfDBLα-IgG1 and-IgG3 were the predominant subclasses. Similar percentage of UCM(31.82%) and SM(33.33%) plasma contained only IgG1, while 13.64% of UCM and 27.78% of SM plasma contained only IgG3. AntiPfDBLα-IgG1 coexpressed with more than one subclass was noted(UCM, 27.27%; SM,16.67%). Obviously, IgG1 coexpressed with IgG3(9.09%) was observed in only UCM plasma. IgG1 was coexpressed with IgG2 in UCM(9.09%) and SM(11.11%) plasma,while IgG1 was coexpressed with IgG4 only in UCM plasma(4.55%). IgG subclasses to P. falciparum antigens were distributed in a similar manner. Only the levels of IgG1, but not IgG3 were significantly higher in UCM than in SM.Conclusions: These data suggest that individuals infected with P. falciparum can develop the anti-Pf EMP1 antibodies with the major contribution of specific IgG subclasses. The balance and the levels of anti-PfDBLα IgG subclasses play a crucial role in antibody mediated protection against severe malaria.

Pattern of Uncomplicated Malaria Treatment and Antimalarial Prescription Practices among Health Workers in the Littoral Region of Cameroon: An Assessment of Ten Years Post-Malaria Treatment Policy Change

Following highly prevalent Plasmodium resistant strains to antimalarial monotherapies in malaria endemic countries, uncomplicated malaria treatment policy changed to artemisinine-based combination therapies (ACTs). After adoption of this new treatment policy in a country, sufficient care is needed to be taken to prevent occurrence of resistance to the latest drugs. As Cameroon shifted to ACT in 2004, this study aimed to assess knowledge and practices of health workers in government health facilities of the Littoral region regarding mild malaria management in health facilities as well as according to prescription qualities of ACTs in leaflets received in pharmacies. A total of 66 physicians and 16 nurses were questioned in 10 health facilities and 503 medical leaflets with ACTs prescriptions were viewed in 17 pharmacies. All medical workers questioned correctly were defined mild malaria and were aware of the antimalarial policy change in Cameroon. Overall ACTs prescription for mild malaria management in children and adult patients was 72.2% and 87.8% respectively. An important proportion of health workers prescribed antimalarial monotherapies and non recommended antimalarial for uncomplicated malaria treatment. 31.7% of participants did not systematically recommend laboratory diagnostic test before antimalarial prescription. Of leaflets viewed in pharmacies, ACTs were prescribed by physicians, nurses and laboratory technicians. Age was the only criteria for ACTs prescription. Appropriate ACTs quality prescription ranged between 81.2% and 94.4%. Of the ACTs prescribed, blisters had the highest (92.9%) appropriate quality prescription and solutions the lowest (83.3%). According to qualification of prescribers, physicians had the highest score (93.1%) of appropriate quality prescription and laboratory technicians the lowest score (28.1%). For all ACTs containing medical leaflets, concomitant medications were recorded namely antipyretic (73.9%), antibiotic (21.9%), non steroid anti-inflammatory (19.9%) or vitamins (18.1%). Data gathered indicated that although health workers were aware of uncomplicated malaria treatment policy change in Cameroon, mild malaria mismanagement was prevailing in health facilities of the Littoral region and ACTs quality prescription in medical leaflets was not optimal. Therefore, awareness is still needed among prescribers in order to prevent or at least slow the occurrence of Plasmodium resistant strains to ACTs in Cameroon.

A Comparative Study of Dihydroartemisin in Compounds in Treatment of Uncomplicated Falciparum Malaria in Kampong of Cambodia

Objective: To compare the safety and efficacy of two compounds of dihydroartemisinin(DHA) -Artekin and Artekin (T) in the treatment of uncomplicated falciparum malaria. Methods:The regimen of 8-tablet for 2 days of Artekin and Artekin (T) were applied to 100 patients with uncomplicated falciparum malaria, who were randomly divided into two groups. Each group contained 50 cases. The cure rate, the mean parasites clearance time, the mean fever clearance and side-effects were observed to assess the safety and efficacy of the compounds used. Results: The mean parasites clearance time was 31. 7±9.0 hours in the Artekin group and 32. 8±8. 8 hours in Artekin (T) group respectively; the mean fever clearance time was 12. 7±7. 2 hours in Artekin group and 16. 5±7. 9 hours in Artekin (T) group; there were no recrudescence case in both groups within the 28 days of follow-up, the cure rates in Artekin group and Artekin (T) groups were 100%. It indicated that the tolerability of both compounds were very good, the side-effects such as nausea, abdominal pain were mild and self-limited. Conclusion: The study preliminarily indicated that the DHA and PQ compounds were of high efficacy, rapid acting and low toxici-ty. Artekin is very promising as a cheap, simple, effective treatment for multi-resistance malaria in Cambodia.

How Not to Miss a Case of Malaria in Emergency Department in Malaria Non-Endemic Areas? Practical Approach &Experiences in Hong Kong

Human malaria is a life-threatening mosquito-borne protozoan parasitic infection in human involving female anopheline mosquitoes as vector for transmission. It is caused by Plasmodium species, most commonly, P. vivax, P. ovale, P. malariae and P. falciparum, and rarely P. knowlesi. Malaria remains a significant global health issue and is a medical emergency. It is also an important cause of morbidity and mortality in endemic areas, particularly in at-risk groups. In Hong Kong, where malaria is non-endemic, more than 20 cases of malaria per year have been notified in recent years. We still have chances encountering patients with malaria presented to public or private emergency departments. High index of clinical suspicious is utmost important for not missing a case of malaria. A practical approach for prompt identification of patients with severe malaria is essential, followed by appropriate initiation of appropriate effective antimalarial treatment within 24 to 48 hours of symptoms onset after blood taken for thick and thin smears for diagnosis. Vigilance with increased awareness of not falling into common diagnostic traps has to be alerted. The risk of missing any case of malaria presenting to emergency department could be largely minimized.