Epidemiological characteristics of Plasmodium malariae malaria in China:a malaria that should not be neglected post elimination

Background Plasmodium malariae was always neglected compared withP.falciparum andP.vivax.In the present study,we aimed to describe the epidemiology of reported cases infected withP.malariae in the past decade to raise awareness of the potential threat of this malaria parasite in China.Methods Individual data of malaria cases infected withP.malariae reported in China in the past decade were collected via the China Information System for Disease Control and Prevention and Parasitic Diseases Information Reporting Management System,to explore their epidemiological characteristics.Pearson Chi-square tests or Fisher’s Exact Test was used in the statistical analysis.Results From 2013 to 2022,a total of 581P.malariae cases were reported in China,and mainly concentrated in 20-59 years old group(P<0.001),and there was no significant trend in the number of cases reported per month.Moreover,four kinds ofP.malariae cases were classified,including 567 imported cases from 41 countries in 8 regions and distributed in 27 provinces(autonomous regions,municipalities)in China,six indigenous cases in a small outbreak in Hainan,seven recurrent cases in Guangdong and Shanghai,and one induced case in Shanghai,respectively.In addition,only 379 cases(65.2%)were diagnosed as malaria on the first visit(P<0.001),and 413 cases(71.1%)were further confirmed asP.malariae cases(P=0.002).Meanwhile,most cases sought healthcare first in the health facilities at the county and prefectural levels,but only 76.7%(161/210)and 73.7%(146/198)cases were diagnosed as malaria,and the accuracy of confirmed diagnosis as malaria cases infected withP.malariae was only 77.2%(156/202)and 69.9%(167/239)in these health facilities respectively.Conclusions Even though malaria cases infected withP.malariae didn’t account for a high proportion of reported malaria cases nationwide,the threat posed by widely distributed imported cases,a small number of indigenous cases,recurrent cases and induced case cannot be ignored in China.Therefore,it is necessary to raise awareness and improve the surveillance and response to the non-falciparum species such asP.malariae,and prevent the reestablishment of malaria transmission after elimination.

Soil-transmitted helminths and plasmodium falciparum malaria among individuals living in different agroecosystems in two rural communities in the mount Cameroon area:a cross-sectional study

Background:Soil-transmitted helminths(STHs)and Plasmodium falciparum infections remain public health problems in Cameroon.A cross-sectional study was carried out in the Mount Cameroon area to determine the prevalence and intensity of STHs and P.falciparum infections in individuals living in different agroecosystems;to assess the influence of these infections on haematological parameters;and to identify the risk factors associated with STH infections.Methods:STH and malaria parasites were detected using the Kato-Katz method and Giemsa staining of blood films,respectively.Complete blood count values were obtained using an automatic haematology analyser.Soil samples were analysed using the sucrose floatation sedimentation method.Categorical and continuous variables were compared as required and logistic regression models were used to assess the risk factors for STH infections and anaemia.Results:Of the 450 participants examined,STHs,P.falciparum and mixed co-infections were detected in 14.0,33.3 and 5.6%of participants,respectively.Significantly higher prevalences of Ascaris(18.8%)and Trichuris(7.9%)infections were observed in participants from tea plantation areas compared to those from banana and palm plantation areas,with similar trends in egg density.P.falciparum prevalence and parasite density were comparable between the different agroecosystems.The overall prevalence of anaemia was 64.2%.The prevalence of haematological manifestations such as moderate(48.0%)and severe(8.0%)anaemia,leucopenia(26.9%)and microcytosis(30.8%)was significantly higher among Plasmodium-STH co-infected participants.Soil samples from plantations showed the highest prevalences of STH eggs compared to soil samples from areas around pit toilets and public water taps.Living in a tea plantation area(OR=3.07),age(AOR=1.49)and lack of access to potable water(OR=2.25)were identified as risk factors for STH infections,while the age groups 15-25 years(OR=2.928)and 26-35 years(OR=2.832),and being female(OR=2.671)were significant risk factors for anaemia.Conclusions:STHs,malaria and anaemia are still of public health concern in plantation communities.Co-infections negatively influence haematological parameters.The tea farming agroecosystem,age and lack of access to potable water were identified as significant risk factors for STH infections.Trial registration:Not applicable.

Modelling the impact of antimalarial quality on the transmission of sulfadoxine-pyrimethamine resistance in Plasmodium falciparum

Background:The use of poor quality antimalarial medicines,including the use of nonrecommended medicines for treatment such as sulfadoxine-pyrimethamine(SP)monotherapy,undermines malaria control and elimination efforts.Furthermore,the use of subtherapeutic doses of the active ingredient(s)can theoretically promote the emergence and transmission of drug resistant parasites.Methods:We developed a deterministic compartmental model to quantify the impact of antimalarial medicine quality on the transmission of SP resistance,and validated it using sensitivity analysis and a comparison with data from Kenya collected in 2006.We modelled human and mosquito population dynamics,incorporating two Plasmodium falciparum subtypes(SP-sensitive and SP-resistant)and both poor quality and good quality(artemether-lumefantrine)antimalarial use.Findings:The model predicted that an increase in human malaria cases,and among these,an increase in the proportion of SP-resistant infections,resulted from an increase in poor quality SP antimalarial use,whether it was full-or half-dose SP monotherapy.Interpretation:Our findings suggest that an increase in poor quality antimalarial use predicts an increase in the transmission of resistance.This highlights the need for stricter control and regulation on the availability and use of poor quality antimalarial medicines,in order to offer safe and effective treatments,and work towards the eradication of malaria.

DETECTION OF PLASMODIUM FALCIPARUM LACTATE DEHYDROGENASE A PROMISING APPROACH TO QUICK DIAGNOSIS OF MALARIA

To establish a quick and applicable diagnostic method has been a major target in immunological research on malaria. Of all approaches studied, circulating antigen (CAg) detection seems to be the most promising. Scientists have encountered tough difficulties in the analysis and purification of malaria parasite antigen because of its high complexity. Studies showed that plasmadium falciparum (P.f) lactate dehydrogenase (pLDH), as a specific CAg of malaria parasite. is apparently different from that of human erythrocytes (rLDH) both in their physical and biochemical characteristics. and is very easy to be identifed. Consequently, pLDH detection has a great potential to be developed into a method for assessing parasitemia. This paper reviewed the methods for the purification. separation, identification of pLDH and the prospect of its clinical applications as an ideal detector of the presence of malaria parasite in order to speed up this research.

Effects of the configuration of a multi epitope chimeric malaria DNA vaccine on its antigenicity to mice

Objective Four B and Th cell epitopes were selected from conservative domain of Plasmodium falciparum antigens to construct two groups of chimeric malaria DNA vaccines with different configurations and their antigenicities were studied Methods The partially synthesized oligonucleotide was annealed, PCR amplified and cloned into a mammalian cell expression vector By using a pair of isocaudamers on the vector, different single copies of B epitopes were multiplied and were tenderly stringed into two groups of chimeric DNA vaccine with different configurations BALB/c mice were immunized with these DNA plasmids by either intramuscular or intradermal injections Results The antisera from the immunized mice tested by ELISA showed that only the configuration which had a single copy of universal T helper cell epitope, CS T3, located at the C terminal of the multi copy B cell epitopes induced a high antibody response The T helper cell epitope at any other position of the peptide, or the double T helper cell epitopes configured with the B cell epitopes did not enhance antibody response, and some configurations even decreased the humoral response to a B cell epitope Conclusion This study demonstrated that both combination and configuration of the epitope may affect the antigenicity of a chimeric multiple antigen