Plasmodium Malariae Infection Research Articles

Assessing the burden of submicroscopic Plasmodium infections in a pre-elimination malaria setting in sub-Saharan Africa, Guinea-Bissau.

Submicroscopic Plasmodium infections can be a source of persistent malaria transmission. The aim of this study was to assess their frequency, distribution, morbidity and associated factors in a pre-elimination malaria setting in sub-Saharan Africa, Guinea-Bissau, where the Plasmodium falciparum is the predominant Plasmodium species. Dried fingerprick whole blood samples from 601 participants in the 2017 national, household-based, cross-sectional survey to estimate malaria prevalence were subjected to DNA extraction. The DNA was used in nested end-point PCR assays targeting genus- and species-specific regions of the Plasmodium 18S rRNA genes. Statistical analysis of socio-demographic, clinical and molecular data was carried out using the Statistical Package for the Social Sciences, version 29. Factors associated with submicroscopic P. falciparum infections and their magnitude were sought using Chi-square test and multiple logistic regression models, respectively. Statistically significant level was considered at P-value < 0.05. Nested PCR assays detected submicroscopic P. falciparum infections in 20.3% (95% CI = 16.8-23.8) of individuals microscopically negative for Plasmodium species in the general population and in 21.4% (95% CI = 9.9-36.5) of microscopically negative pregnant women. Submicroscopic Plasmodium malariae infections were also detected as co-infections in 3.0% individuals who were microscopically positive only for P. falciparum. Infections with other Plasmodium species were not detected. Submicroscopic P. falciparum infections were not associated with age, sex, or the presence of fever. A logistic regression model adjusted for ethnicity and health region showed that individuals from the Balanta and Bijagos ethnic groups, most of whom live in the low malaria-transmission areas of Quinara and Bissau, and the Bijagos archipelago, respectively, were less likely to have submicroscopic P. falciparum infections than individuals from the large Fula ethnic group, most of whom live in the high malaria-transmission area of Gabu. Submicroscopic P. falciparum infections were not associated with anaemia in children under 5years of age. The results obtained highlight the contribution of asymptomatic and submicroscopic P. falciparum infections to malaria transmission in high malaria-transmission areas and the need for molecular-based tools to detect submicroscopic Plasmodium species.

Poor performance of malaria rapid diagnostic tests for the detection of Plasmodium malariae among returned international travellers in China

BackgroundMalaria is a worldwide infectious disease. For countries that have achieved malaria elimination, the prevention of re-establishment due to infections in returned travellers has become important. The accurate and timely diagnosis of malaria is the key in preventing re-establishment, and malaria rapid diagnostic tests (RDTs) are frequently used due to their convenience. However, the RDT performance in Plasmodium malariae (P. malariae) infection diagnosis remains unknown.MethodsThis study analysed epidemiological features and diagnosis patterns of imported P. malariae cases from 2013 to 2020 in Jiangsu Province and evaluated the sensitivity of four parasite enzyme lactate dehydrogenase (pLDH)-targeting RDTs (Wondfo, SD BIONLINE, CareStart and BioPerfectus) and one aldolase-targeting RDT(BinaxNOW) for P. malariae detection. Furthermore, influential factors were investigated, including parasitaemia load, pLDH concentration and target gene polymorphisms.ResultsThe median duration from symptom onset to diagnosis among patients with P. malariae infection was 3 days, which was longer than that with Plasmodium falciparum (P. falciparum) infection. The RDTs had a low detection rate (39/69, 56.5%) among P. malariae cases. All tested RDT brands had poor performance in P. malariae detection. All the brands except the worst-performing SD BIOLINE, achieved 75% sensitivity only when the parasite density was higher than 5000 parasites/μL. Both pLDH and aldolase showed relatively conserved and low gene polymorphism rates.ConclusionsThe diagnosis of imported P. malariae cases was delayed. The RDTs had poor performance in P. malariae diagnosis and may threaten the prevention of malaria re-establishment from returned travellers. The improved RDTs or nucleic acid tests for P. malariae cases are urgently needed for the detection of imported cases in the future.

The presence of Plasmodium malariae and Plasmodium knowlesi in near malaria elimination setting in western Indonesia

BackgroundIndonesia is progressing towards malaria elimination. To achieve this goal, intervention measures must be addressed to cover all Plasmodium species. Comprehensive control measures and surveillance programmes must be intensified. This study aims to determine the prevalence of microscopic and submicroscopic malaria in Langkat district, North Sumatera Province, Indonesia.MethodsA cross-sectional survey was conducted in six villages in Langkat district, North Sumatera Province in June 2019. Data were recorded using a standardized questionnaire. Finger pricked blood samples were obtained for malaria examination using rapid diagnostic test, thick and thin blood smears, and polymerase chain reaction.ResultsA total of 342 individuals were included in the study. Of them, one (0.3%) had a microscopic Plasmodium malariae infection, no positive RDT examination, and three (0.9%) were positive for P. malariae (n = 1) and Plasmodium knowlesi (n = 2). The distribution of bed net ownership was owned by 40% of the study participants. The participants had a house within a radius of 100–500 m from the forest (86.3%) and had the housing material of cement floor (56.1%), a tin roof (82.2%), wooden wall (35.7%), bamboo wall (28.1%), and brick wall (21.6%).ConclusionMalaria incidence has substantially decreased in Langkat, North Sumatera, Indonesia. However, submicroscopic infection remains in the population and may contribute to further transmission. Surveillance should include the detection of microscopic undetected parasites, to enable the achievement of malaria elimination.

An innovative three-layer strategy in response to a quartan malaria outbreak among forest goers in Hainan Island, China: a retrospective study

BackgroundAn outbreak of Plasmodiummalariae infection among forest goers in Sanya City of Hainan Island, China was reported in 2015. In response to this outbreak, an innovative three-layer strategy (TLS) targeted forest goers was adapted based on the 1-3-7 approach.Main textKey elements of TLS are: (i) The village with five malaria cases and adjacent villages were set as the first layer. All residents including forest goers were taken as the high-risk population (HRP). Active case detection (ACD) by blood smear microscopy and PCR was selected as the primary measure, and passive case detection (PCD) as complementary measure. One case was identified under TLS implementation. (ii) The township with cases (Gaofeng Town) and the nearby towns were chosen as the second layer. Only forest goers were screened by ACD, while PCD as a routine screening method. 7831 blood smears collected by ACD and PCD and tested with negative results. (iii) The city with cases (Sanya City) and others 12 counties/county-level cities were selected as the third layer. Malaria cases were monitored passively. A total of 77,555 blood slides were screened by PCD with zero positive sample. For each layer, the malaria vector mosquitoes were monitored using light traps, cattle-baited/human-bait traps.Anophelesminimus (dominant species), An.sinensis and An.dirus were captured. Vector control measures mainly include insecticide residual spraying and long-lasting insecticide nets. The capacity of clinicians, public health practitioners and laboratory technicians has been improved through training. During 2016‒2018, TLS and chemoprophylaxis were implemented in the same areas. In the first layer, all residents were monitored by ACD, and malaria chemoprophylaxis were distributed, 89.5% of forest goers were using chemoprophylaxis against malaria. The blood smears (3126 by ACD plus 1516 by PCD) were with zero positive results. Chemoprophylaxis and ACD were offered to forest goers once a year, and PCD in residents as a complementary measure in the second and third layer, 77.8% and 95.1% of forest goers received chemoprophylaxis. In each layer, vector surveillance and control of malaria and trainings for medical staff were still in place.ConclusionsTLS was effective in blocking the outbreak by P.malariae among forest goers in Hainan in malaria elimination stage. However, whether it could prevent the malaria resurgence in the post-elimination phase needs to be further assessed.Graphical

P. falciparum msp1 and msp2 genetic diversity in P. falciparum single and mixed infection with P. malariae among the asymptomatic population in Southern Benin.

Plasmodium falciparum and Plasmodium malariae infections are prevalent in malaria-endemic countries. However, very little is known about their interactions especially the effect of P. malariae on P. falciparum genetic diversity. This study aimed to assess P. falciparum genetic diversity in P. falciparum and mixed infection P. falciparum/P. malariae isolates among the asymptomatic populations in Southern Benin. Two hundred and fifty blood samples (125 of P. falciparum and 125 P. falciparum/P. malariae isolates) were analysed by a nested PCR amplification of msp1 and msp2 genes. The R033 allelic family was the most represented for the msp1 gene in mono and mixed infection isolates (99.2% vs 86.4%), while the K1 family had the lowest frequency (38.3% vs 20.4%). However, with the msp2 gene, the two allelic families displayed similar frequencies in P. falciparum isolates while the 3D7 allelic family was more represented in P. falciparum/P. malariae isolates (88.7%). Polyclonal infections were also lower (62.9%) in P. falciparum/P. malariae isolates (p<0.05). Overall, 96 individual alleles were identified (47 for msp1 and 49 for msp2) in P. falciparum isolates while a total of 50 individual alleles were identified (23 for msp1 and 27 for msp2) in P. falciparum/P. malariae isolates. The Multiplicity of Infection (MOI) was lower in P. falciparum/P. malariae isolates (p<0.05). This study revealed a lower genetic diversity of P. falciparum in P. falciparum/P. malariae isolates using msp1 and msp2 genes among the asymptomatic population in Southern Benin.

Prevalence of non-Plasmodium falciparum species in southern districts of Brazzaville in The Republic of the Congo

BackgroundAlthough Plasmodium falciparum infection is largely documented and this parasite is the main target for malaria eradication, other Plasmodium species persist, and these require more attention in Africa. Information on the epidemiological situation of non-P. falciparum species infections is scarce in many countries, including in the Democratic Republic of the Congo (hereafter Republic of the Congo) where malaria is highly endemic. The aim of this study was to determine the prevalence and distribution of non-P. falciparum species infections in the region south of Brazzaville.MethodsA cross-sectional survey was conducted in volunteers living in rural and urban settings during the dry and rainy seasons in 2021. Socio-demographic and clinical parameters were recorded. Plasmodium infection in blood samples was detected by microscopic analysis and nested PCR (sub-microscopic analysis).ResultsOf the 773 participants enrolled in the study, 93.7% were from the rural area, of whom 97% were afebrile. The prevalence of microscopic and sub-microscopic Plasmodium spp. infection was 31.2% and 63.7%, respectively. Microscopic Plasmodium malariae infection was found in 1.3% of participants, while sub-microscopic studies detected a prevalence of 14.9% for P. malariae and 5.3% for Plasmodium ovale. The rate of co-infection of P. malariae or P. ovale with P. falciparum was 8.3% and 2.6%, respectively. Higher rates of sub-microscopic infection were reported for the urban area without seasonal fluctuation. In contrast, non-P. falciparum species infection was more pronounced in the rural area, with the associated risk of the prevalence of sub-microscopic P. malariae infection increasing during the dry season.ConclusionThere is a need to include non-P. falciparum species in malaria control programs, surveillance measures and eradication strategies in the Republic of the Congo.Graphical

Surveillance of Plasmodium malariae infection among inhabitants of rural areas in Ouidah-Kpomasse-Tori Bossito health district, Benin.

Among the Plasmodium species that infect humans, P. falciparum has been largely studied in malaria endemic areas. However, P. malariae infection is less documented among the human population. This study aimed to monitor the prevalence and distribution of P. malariae in Southern Benin. A cross-sectional survey was conducted in rural localities in the Ouidah-Kpomasse-Tori Bossito (OKT) health district in Southern Benin from June to October 2019. Socio-demographic data were collected using a questionnaire, while malaria infection data were obtained on the one hand by microscopy diagnosis and, on the other, by nested polymerase chain reaction (PCR). Based on microscopy, the prevalence of P. malariae mono-infection and coinfection of P. falciparum, P. malariae was respectively 2.3% and 1.2% in the OKT health district. This prevalence was higher (P < 0.01) than that reported by Damien et al. (2010) 10 years ago in the same study area with 0.7% and 0.3% of P. malariae and P. falciparum/P. malariae, respectively. Based on PCR analysis, P. malariae prevalence was 14.1%, including 5.2% of mono-infection and 8.9% of mixed infection with P. falciparum. Sub-microscopic Plasmodium infections were high (30.6%) and more pronounced in older participants (>20 years). The present study revealed that P. malariae increased in the OKT health district with a high prevalence of submicroscopic infection. Since our results provide valuable evidence of increasing P. malariae infection, the National Malaria Control Programs (NMCPs) must consider P. malariae when designing future measures for effective control and malaria treatment.

Neglected malaria parasites in hard-to-reach areas of Odisha, India: implications in elimination programme

BackgroundInformation on the foci of Plasmodium species infections is essential for any country heading towards elimination. Odisha, one of the malaria-endemic states of India is targeting elimination of malaria by 2030. To support decision-making regarding targeted intervention, the distribution of Plasmodium species infections was investigated in hard-to-reach areas where a special malaria elimination drive, namely Durgama Anchalare Malaria Nirakaran (DAMaN) began in 2017.MethodsA cross-sectional survey was conducted in 2228 households during July to November 2019 in six districts, to evaluate the occurrence of Plasmodium species. The species were identified by polymerase chain reaction (PCR) followed by sequencing, in case of Plasmodium ovale.ResultsOf the 3557 blood specimens tested, malaria infection was detected in 282 (7.8%) specimens by PCR. Of the total positive samples, 14.1% were P. ovale spp. and 10.3% were Plasmodium malariae infections. The majority of P. ovale spp. (75.8%) infections were mixed with either Plasmodium falciparum and/or Plasmodium vivax and found to be distributed in three geophysical regions (Northern-plateau, Central Tableland and Eastern Ghat) of the State, while P. malariae has been found in Northern-plateau and Eastern Ghat regions. Speciation revealed occurrence of both Plasmodium ovale curtisi (classic type) and Plasmodium ovale wallikeri (variant type).ConclusionsIn the present study a considerable number of P. ovale spp. and P. malariae were detected in a wide geographical areas of Odisha State, which contributes around 40% of the country’s total malaria burden. For successful elimination of malaria within the framework of national programme, P. ovale spp. along with P. malariae needs to be incorporated in surveillance system, especially when P. falciparum and P. vivax spp. are in rapid decline.

Mixed Plasmodium malariae Infections Were Underdetected in a Malaria Endemic Area in the Amazon Region, Brazil.

Plasmodium malariae infections are often asymptomatic and long-lasting. Mixed infections are often underdetected in areas where P. malariae, P. vivax, and P. falciparum are coendemic. In this study, we described the occurrence of these species circulating as single or mixed infections in Pará state, Brazil, in the Amazon region, with the purpose of clarifying the impact of misidentification of parasite species based only on morphological description using thick blood smear. By using real-time polymerase chain reaction based on the amplification of the mitochondrial DNA, we detected a prevalence of 46% (58/126) mixed infections with 33.3% P. malariae/P. vivax which were read as P. vivax monoinfections by microscopy detection. Our findings confirmed the high circulation of P. malariae in a malaria endemic area in the Brazilian Amazon region.

Plasmodium malariae infections as a cause of febrile disease in an area of high Plasmodium falciparum transmission intensity in Eastern Uganda

BackgroundPlasmodium falciparum is responsible for the vast majority of (severe) clinical malaria cases in most African settings. Other Plasmodium species often go undiagnosed but may still have clinical consequences.Case presentationHere, five cases of Plasmodium malariae infections from Eastern Uganda (aged 2–39 years) are presented. These infections were all initially mistaken for P. falciparum, but Plasmodium schizonts (up to 2080/µL) were identified by microscopy. Clinical signs included history of fever and mild anaemia.ConclusionThese findings highlight the importance of considering non-falciparum species as the cause of clinical malaria. In areas of intense P. falciparum transmission, where rapid diagnostic tests that detect only P. falciparum antigens are commonly used, non-falciparum malaria cases may be missed.

Epidemic situation and diagnosis of imported malaria in Jiangsu, 2015-2019

Objective To elaborate the epidemic of imported malaria in Jiangsu province from 2015 to 2019, and to prevent the importation and re-transmission of malaria, and we provide information for malaria control and elimination. Methods Data on imported malaria cases in Jiangsu Province from 2015-2019 were collected and sorted through the National Infectious Diseases Information Reporting Management System (IDIRMS) and the Parasitic Diseases Information Reporting Management System (PDIRMS). The incidence and distribution of malaria were described in Jiangsu Province from 2015 to 2019. The distribution of three dimension, diagnostic institutions and diagnostic timeliness of imported malaria cases were described and analyzed. Results From 2015 to 2019, a total of 1 439 cases were reported in Jiangsu Province, of which 1 436 were imported cases, and 3 cases were blood transfusion infection cases. The reported cases were comprised of Plasmodium falciparum (1 075, 74.7%), Plasmodium vivax (63, 4.4%), Plasmodium ovale (233, 16.2%), Plasmodium malariae (65, 4.5%), and mixed infections (3, 0.2%). Imported malaria cases mainly came from Africa (97.5%, 1 400/1 436), Asia (1.9%, 28/1 436), South America and Oceania (0.6%, 8/1 436). The cases were reported from 13 cities in Jiangsu Province. The main imported malaria cases were young men aged 35-<50 years. In January, June and October, more cases were reported than other months. And 83.2% of the cases were diagnosed by medical institutions. The percentage of cases diagnosed by disease control agencies has decreased year by year ( P <0.05). The percentage of patients with more than 9 days time interval between onset and diagnosis in 2019 was significantly lower than that in the previous four years ( P <0.01). Conclusion Malaria epidemic situation in Jiangsu Province has been stable in recent five years. Most malaria cases are imported from abroad, a small part of malaria cases are infected by blood transfusion. The interval between onset and diagnosis is shorter. Prevention of the re-transmisson of imported malaria, improving the efficiency of diagnosis and treatment, and strengthen health education are very important for malaria prevention in Jiangsu Province. 摘要:目的 分析江苏省2015—2019年输人性疟疾疫情流行特征及诊断情况,为防止疟疾输人再传播,巩固消除 疟疾成果提供科学参考。 方法 疟疾疫情资料来自国家传染病监测系统和寄生虫病防治信息管理系统,采用流行病 学研究 方法 ,描述2015—2019年江苏省疟疾发病、感染来源和病例三间分布情况,对输人性疟疾病例的诊断以及发病 到诊断的时间间隔进行分析。 结果 2015—2019年,江苏省共报告1 439例疟疾病例,其中1 436例为境外输人病例,3例为输血感染病例。1 439例疟疾病例中,恶性疟1 075例（占74.7%)、间日疟63例（占4.4%)、卵形疟233例（占 16.2%)、三日疟65例（占4.5%)、同一时间发病的混合感染病例3例（占0.2%)。境外输人性疟疾病例中,1 400例来自非 洲（占97.5%),其他来自亚洲28例（占1.9%),以及南美洲和大洋洲8例（占0.6%)。江苏省13个设区市均有疟疾病例报 告;疟疾病例以35~<50岁男性青壮年居多,每年的1、6和10月出现病例报告髙峰。82.3%的病例由医疗机构诊断,由 疾控机构诊断的病例占比逐年降低( P <0.05)。2019年发病到确诊超过9 d的病人所占比明显低于前四年( P <0.01)。 结论 近5年江苏省疟疾疫情稳定,绝大部分为境外输人性病例,存在少数输血感染;病人就诊到确诊间隔时间有所缩 短。继续做好风险人群健康宣教,提髙医疗机构诊治能力,防止发生境外输人再传播,是今后疟疾防控工作的重点。

Development of a Novel Cytochrome b Real-Time PCR Assay for Identification of Plasmodium malariae

This article aims to establish a novel cytochrome b real-time PCR assay using Taqman probe for identification of P. malariae and its discrimination from other Plasmodium human infecting species. The optimization of real-time PCR assay with 1X QuantiTect Probe PCR Master Mix, primers and probe used at concentrations of 0.4 μM and 0.1 μM, respectively; and 2.5 mM MgCl2, 5 μl DNA template and deionized H2O of 20 μl, was performed using a real-time PCR instrument. The developed real-time PCR assay was evaluated for the limit of detection, stability on standard panels (109-100 copies/ µl), as well as the sensitivity, specificity on control groups. The probit analysis demonstrates that the 95% detection limit was &lt;0.5 parasite/μl, both the sensitivity and specificity of the assay were 100% when evaluated on the control groups. Additionally, the assay initially evaluated on 41 clinical samples including 21 malaria samples and 20 samples of volunteer blood donors, identified 1 positive sample with P. malariae from the disease group, which shows a concordant result with nested PCR. This novel Cyt b real-time PCR assay for identifying P. malariae may also facilitate earlier discrimination of P. malariae from other Plasmodium parasites with high sensitivity.&#x0D; Keywords&#x0D; Cytochrome b, malaria parasite, plasmodium malariae, mitochondria, real-time PCR.&#x0D; References&#x0D; [1] B. Singh, C. 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Global prevalence and mortality of severe Plasmodium malariae infection: a systematic review and meta-analysis

BackgroundSevere complications among patients with Plasmodium malariae infection are rare. This is the first systematic review and meta-analysis demonstrating the global prevalence and mortality of severe P. malariae infection in humans.MethodsThe systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. All research articles published on the severity and mortality of P. malariae infection cases in humans were retrieved from three public databases: PubMed, Scopus, and ISI Web of Science. The pooled prevalence estimate and 95% confidence interval (CI) of complications in patients with P. malariae malaria was analysed using the random-effects model provided in Stata software. The pooled odds ratio (OR) and 95% CI of severe malaria for P. malariae infection and Plasmodium falciparum infection were analysed using Review Manager software.ResultsSix studies were used to estimate the pooled prevalence of severe P. malariae malaria. Out of 10,520 patients infected with P. malariae, the pooled prevalence estimate of severe P. malariae infection was 3% (95% CI 2–5%), with high heterogeneity (I2: 90.7%). Severe anaemia (3.32%), pulmonary complications (0.46%), and renal impairments (0.24%) were the most common severe complications found in patients with P. malariae infection. The pooled proportion of severe anaemia for P. malariae infection and P. falciparum infection was comparable among the four included studies (OR: 0.74, 95% CI 0.22–2.45, I2 = 98%). The pooled proportion of pulmonary complications was comparable between patients with P. malariae infection and those with P. falciparum infection among the four included studies (OR: 1.44; 95% CI 0.17–12.31, I2: 92%). For renal complications, the funnel plot showed that the pooled proportion of renal complications for P. malariae infection and P. falciparum infection was comparable among the four included studies (OR: 0.94, 95% CI 0.18–4.93, I2: 91%). The mortality rate of patients with P. malariae infection was 0.17% (18/10,502 cases).ConclusionsThis systematic review demonstrated that approximately two percent of patients with P. malariae infection developed severe complications, with a low mortality rate. Severe anaemia, pulmonary involvement, and renal impairment were the most common complications found in patients with P. malariae infection. Although a low prevalence and low mortality of P. malariae infection have been reported, patients with P. malariae infection need to be investigated for severe anaemia and, if present, treated aggressively to prevent anaemia-related death.

Plasmodium spp. mixed infection leading to severe malaria: a systematic review and meta-analysis

Mixed Plasmodium malaria infections can lead to severe malaria. This systematic review and meta-analysis aimed to explore the prevalence of severe mixed Plasmodium malaria infection and to compare it with the prevalence of severe P. falciparum malaria mono-infection across the included studies. Original English-language research articles from PubMed, Scopus, and ISI Web of Science were identified and screened. Articles reporting the number of mixed infections and the number of severe mixed infections were used to determine the main outcome of this study, while the number of P. falciparum infections and the number of severe P. falciparum infections were used to determine the secondary outcome of this study. For the main outcome, the pooled prevalence and 95% confidence interval (CI) of severe mixed infections was analysed using STATA software version 15.0 (Stata Corp, College Station, TX, USA). For the secondary outcome, the rate of severe mixed infections compared to severe P. falciparum infections was analysed using the meta-analysis approach, and summary odds ratios (ORs) and 95% CIs were calculated. Random-effects models were used to produce the summary ORs. The Mantel–Haenszel method and calculated I2 were also reported to test whether there was heterogeneity among the included studies. Publication bias was also assessed using funnel plots. The meta-analysis of secondary outcomes was conducted using Review Manager 5.3 software (Cochrane Community). A total of 894,561 malaria patients were reported in all 16 included studies. Overall, a pooled analysis showed that 9% (2,006/35,768, 95% CI 7.0–12.0%) of patients with mixed Plasmodium infection had severe mixed infection. A meta-analysis of 14 studies demonstrated that patients with mixed Plasmodium infection (1,999/35,755) and patients with P. falciparum malaria (9,249/294,397) had an equal risk of developing severe malaria (OR 0.93, 95% CI 0.59–1.44). Both mixed infection and P. falciparum mono-infection showed a similar trend of complications in which severe anaemia, pulmonary failure, and renal impairment were the three most common complications found. However, patients with mixed infection had a higher proportion of severe anaemia and pulmonary complications than those with P. falciparum infection. Moreover, patients with mixed infection had a higher proportion of multiple organ failure than those with P. falciparum mono-infection. Mixed Plasmodium spp. infections were common but often unrecognized or underestimated, leading to severe complications among these malaria patients. Therefore, in routine clinical laboratories, using an accurate combination of diagnostic procedures to identify suspected patients with mixed infections is crucial for therapeutic decisions, prompt treatment, and effective patient management.

Probing the composition of Plasmodium species contained in malaria infections in the Eastern region of Ghana

BackgroundAsymptomatic falciparum and non-falciparum malaria infections are major challenges to malaria control interventions, as they remain a source of continual infection in the community. This becomes even more important as the debate moves towards elimination and eradication. This study sought to quantify the burden of Plasmodium malaria infection in seven communities in the Eastern Region of Ghana.MethodsThe cross-sectional study recruited 729 participants aged 85 years old and below from 7 closely linked communities. Finger pricked blood was used to prepare thick and thin blood smears as well as spot filter paper and an histidine rich protein 2 (HRP2) rapid diagnostic test kit (RDT). Genomic DNA was extracted from the filter paper dry blood spot (DBS) and used in PCR to amplify the Plasmodium 18S rRNA gene using species specific PCR.Results96.6% of the participants were identified as afebrile, with axillary temperatures below 37.5 °C. PCR identified 66% of the participants to harbor malaria parasites, with 9 P. malariae and 7 P. ovale mono-infections accounting for 2.2% and P. falciparum combined with either 36 P. malariae or 25 P. ovale infections, accounting for 13.3%. Parasite prevalence by microscopy (32%) was similar to the RDT positivity rate (33%). False positive RDT results ranged from 64.6% in children aged between 5 and 9 years to 10% in adults aged 20 years and above. No significant differences were observed in falciparum and non-falciparum parasite carriage at the community level, however young adults aged between 15 and 19 years had the highest prevalence (34.8% (16/46)) of P. falciparum and P. malariae parasite carriage whilst children aged between 5 and 9 years had the highest level (11.4% (14/123)) of P. ovale carriage.ConclusionThe high rate of misidentification of non-falciparum parasites and the total absence of detection of P. ovale by microscopy suggests that more sensitive malaria diagnostic tools including molecular assays are required to accurately determine the prevalence of carriers of non-falciparum parasites and low density P. falciparum infections, especially during national surveillance exercises. Additionally, malaria control interventions targeting the non-falciparum species P. malariae and P. ovale parasites are needed.

Two cases of long-lasting, sub-microscopic Plasmodium malariae infections in adults from coastal Tanzania

BackgroundMalaria is endemic in Tanzania with majority of clinical cases caused by Plasmodium falciparum. Additionally, Plasmodium malariae and Plasmodium ovale spp. are also present and clinical manifestations caused by these infections are not well described. Clinical episodes caused by P. malariae infections are often characterized by a relatively mild illness with a low number of parasites, which can persist for long periods. In this report, two cases of P. malariae infections that were identified during a clinical trial evaluating the P. falciparum malaria vaccine candidate, PfSPZ Vaccine are described. The two participants were followed up and monitored for clinical and laboratory parameters to assess vaccine safety providing the opportunity to study clinical manifestations of P. malariae over 4 months.Case presentationTwo young, healthy Tanzanian men infected with low density asexual blood stage P. malariae diagnosed by quantitative polymerase chain reaction (qPCR) are described. Retrospective analysis of collected and stored blood samples revealed that the two volunteers had constant asexual blood stage parasitaemia for more than 4 months. During the 132 days of infection, the volunteers’ vital signs, body temperature and serum biochemistry all remained within normal ranges. Haematological abnormalities, which were transiently outside normal ranges, were regarded as not clinically significant. During this time period, four consecutive evaluations of blood samples by thick blood smear microscopy conducted by an experienced microscopist were all negative, indicating the presence of low-density sub-microscopic infections.ConclusionsThe two cases of P. malariae infections presented here confirm the ability of this Plasmodium species to persist at low density in the human host for extended time periods without causing clinical symptoms. The presented data also demonstrate that clinical study sites in malaria endemic regions need to have a strong malaria diagnostic infrastructure, including the ability of capturing sub-microscopic parasitaemia and differentiation of Plasmodium species.Trial registration ClinicalTrials.gov: NCT02613520, https://clinicaltrials.gov/ct2/show/NCT02613520, Registered: November 24th 2015, Enrolment of the first participant to the trial: December 15th 2015, Trial was registered before the first participant was enrolled

Plasmodium malariae and Plasmodium ovale infections and their association with common red blood cell polymorphisms in a highly endemic area of Uganda.

Plasmodium ovale and Plasmodium malariae infections are scarcely studied in sub-Saharan Africa, where the Plasmodium falciparum species predominates. The objective of this study is to investigate the prevalence of P. ovale and P. malariae infections and their relationship with common red blood cell polymorphisms in a cohort of 509 individuals from Uganda. Three cross-sectional surveys were conducted in individuals of 1-10 and >20 y of age from the Apac district at baseline and 6 and 16 weeks after drug treatment. Malaria infections were assessed by polymerase chain reaction and genotyping was performed for the sickle-cell allele, α-thalassaemia and glucose-6-phosphate dehydrogenase. At baseline, the prevalence of infection was 7.5%, 12.6% and 57.4% for P. ovale, P. malariae and P. falciparum species, respectively. Co-infections were present in 14.1% of individuals, all including P. falciparum parasites. In children 1-5 y of age, the prevalence of P. ovale mono-infections increased significantly from 1.7% to 7.3% over time (p=0.004) while the prevalence of P. malariae and P. falciparum infections declined significantly during this study. After adjusting for confounding and multiple testing, only α-thalassaemia had a statistically significant increase in the odds of P. falciparum infections (odds ratio 1.93 [95% confidence interval 1.26 to 2.94]). Common red blood cell polymorphisms do not show strong effects on mild Plasmodium infections in this Ugandan population. To understand the extent of this result, similar studies should be carried out in other populations using larger cohorts.

Prevalence and distribution of human malarial infection in district Multan, Punjab, Pakistan

Abstract The present study was undertaken during 2015-17 with the objective to provide data of malarial infections in human population based on incidences in twenty different localities of district Multan, Punjab, Pakistan. The blood slides of suspected patients were studied to identify the malarial parasites. Slide positivity was found to be 1478 (39.20%) out of 3770 and Plasmodium vivax infection was 905 (61.23%), Plasmodium falciparum 425 (28.75%) and mixed species (P. vivax and P. falciparum) 148 (10.01%) were identified. In the month of December, 150 cases (73.25%) of P. vivax infection counted to be the highest, whereas, 42 cases (58.33%) of P. vivax in the month of September were recorded. The P. falciparum infection remained highest in the month of August with 58 cases (25.66%) and lowest in the month of May with 24 (23.76%). Similarly infection of mixed species remained highest 30 (13.27%) in August and lowest 7 (7.60%) in the month of February. Infection in male was highest 850 (57.51%) and female was lowest 628 (42.48%). No incidence of Plasmodium ovale and Plasmodium malariae infection was to be observed in this study. The results of present research work concluded that P. vivax and P. falciparum are serious health hazards which can ultimately lead to serious cerebral malaria problems. However, no association was found between age group, sex and type of infection. Therefore, it can be concluded that the incidence of any type of infection may happened from person to person of any age group and in any sex. Keywords: Incidence; Infection; Multan; Mixed species; Plasmodium falciparum; Plasmodium vivax http://dx.doi.org/10.19045/bspab.2019.80029

Geographical and temporal trends and seasonal relapse in Plasmodium ovale spp. and Plasmodium malariae infections imported to the UK between 1987 and 2015

BackgroundPlasmodium ovale spp. and P. malariae cause illness in endemic regions and returning travellers. Far less is known about these species than P. falciparum and P. vivax.MethodsThe UK national surveillance data, collected 1987 to 2015, were collated with the International Passenger Survey and climatic data to determine geographical, temporal and seasonal trends of imported P. ovale spp. and P. malariae infection.ResultsOf 52,242 notified cases of malaria, 6.04% (3157) were caused by P. ovale spp. and 1.61% (841) by P. malariae; mortality was 0.03% (1) and 0.12% (1), respectively. Almost all travellers acquired infection in West or East Africa. Infection rate per travel episode fell fivefold during the study period. The median latency of P. malariae and P. ovale spp. was 18 and 76 days, respectively; delayed presentation occurred with both species. The latency of P. ovale spp. infection imported from West Africa was significantly shorter in those arriving in the UK during the West African peak malarial season compared to those arriving outside it (44 days vs 94 days, p < 0.0001), implying that relapse synchronises with the period of high malarial transmission. This trend was not seen in P. ovale spp. imported from East Africa nor in P. malariae.ConclusionIn West Africa, where malaria transmission is highly seasonal, P. ovale spp. may have evolved to relapse during the malarial high transmission season. This has public health implications. Deaths are very rare, supporting current guidelines emphasising outpatient treatment. However, late presentations do occur.

Analysis of the trend of malaria prevalence in Ataye, North Shoa, Ethiopia between 2013 and 2017

BackgroundMalaria is one of the major public health problems worldwide. In Ethiopia, there is a significant decline in disease burden; however, the overall trend of malaria prevalence is not studied or well-documented in different localities. Hence, the initiation of this study was to analyse the 5-year trends of malaria prevalence in Ataye, North Shoa, Ethiopia.MethodsA retrospective laboratory record review was conducted in Ataye Hospital, North-Shoa, Ethiopia. Malaria data reported from 2013 to 2017 were carefully reviewed from January to March 2018.ResultsA total of 31,810 blood films were prepared and examined from malaria-suspected patients at Ataye District Hospital from 2013 to 2017. Of the examined blood films, 2670 (8.4%) were microscopically confirmed malaria cases. The trend of malaria prevalence in the present study seems non- fluctuating. Plasmodium falciparum and Plasmodium vivax accounted for 2087 (78.2%) and 557 (20.9%) cases, respectively. From total positive cases, 1.0% of cases were mixed P. falciparum/P. vivax infections, and that no Plasmodium malariae and Plasmodium ovale infections were found by malaria microscopists. Malaria cases were higher in males 1584 (5.0%) than females 1086 (3.4%). With regard to age groups, higher numbers of malaria cases were observed in age group 15–45 years old. Malaria cases were high in spring (September to December), which is a peak malaria transmission period in Ethiopia.ConclusionMalaria is still among the major public health problems in the country. P. falciparum is the dominant species in the study area followed by P. vivax. Enhancing malaria detection and speciation skill of laboratory personnel and scaling up malaria control and prevention activities are very crucial to significantly reduce the burden of malaria in the study area.