High Parasitemia Research Articles

Determining the prevalence and density of asymptomatic Plasmodium falciparum infections in low and high transmission settings in Western Kenya

Background/Objective: Malaria remains a global health burden as 2018 saw 228 million cases worldwide. Pre-elimination efforts aim to decrease disease transmission, which depends on development of asexual parasites to sexual gametocytes within the human host. To better determine the relationship between asexual parasites and gametocytes, we aim to quantify both stages within the same blood sample by developing a multiplex RT-qPCR assay. We hypothesize that gametocytemia decreases linearly with asexual parasitemia at higher parasitemias but increases at lower parasitemia to improve transmission probability. 
 
 Methods: We conducted a cross-sectional survey of healthy participants aged 0 to 92 years at four sites in Western Kenya (Ajigo, Webuye, Kipsamoite, Kapsisywa) with varying levels of transmission to determine prevalence of asymptomatic P. falciparum blood-stage infections. Parasite density was quantified by light microscopy and by quantitative PCR of genomic DNA isolated from dried blood spots using varATS primers. For varATS-positive samples, we isolated RNA from whole-blood and performed stage-specific quantification by multiplex Taqman RT-qPCR targeting PfPIESP2 (asexual), Pfs25 (female), and Pfs230p (male). 
 
 Results: Among all participants, 127 of 1355 (9.37%) were positive for asymptomatic P. falciparum infection by varATS-qPCR. Using varATS positivity as the standard, multiplex RT-qPCR targeting PfPIESP2 yielded a sensitivity of 78%. Across sites, overall parasite prevalence and gametocyte prevalence were highest in Ajigo (42.1%; 36%) followed by Webuye (10.5%; 9%) and Kipsamoite/Kapsisywa (0.873%; 0.1%). Pfs25-quantified gametocytemia decreased with decreasing varATS-quantified asexual parasitemia; however, the data poorly fit a linear model (R2 = 0.088). 
 
 Conclusions: PfPIESP2 detected 78% of varATS-positive samples, suggesting it may be poorly sensitive at detecting low-density blood-stage infections. Assay design may improve with a more sensitive gene target and further optimization. Based on quantification results, the relationship between gametocytemia and asexual parasitemia appears direct but non-linear. Further work is necessary to better model the relationship between stage-specific parasitemia levels.

Erythrocyte Binding Activity of PkDBPαII of Plasmodium knowlesi Isolated from High and Low Parasitemia Cases

Invasion of Plasmodium knowlesi merozoite into human erythrocytes involves molecular interaction between the parasite's Duffy binding protein (PkDBPαII) and the Duffy antigen receptor for chemokines on the erythrocytes. This study investigates the binding activity of human erythrocyte with PkDBPαII of P. knowlesi isolates from high and low parasitemic patients in an erythrocyte binding assay. The binding activity was determined by counting the number and measuring the size of rosettes formed in the assay. The protein PkDBPαII of P. knowlesi isolated from low parasitemia cases produced significantly higher number of rosettes with human erythrocytes than high parasitemia case isolates (65.5 ± 12.9 and 17.2 ± 5.5, respectively). Interestingly, PkDBPαII of isolates from high parasitemia cases formed significantly larger rosettes with human erythrocytes than PkDBPαII of isolates from low parasitemia cases (18,000 ± 13,000 µm2 and 1,315 ± 623 µm2, respectively).

Eugenol disrupts Plasmodium falciparum intracellular development during the erythrocytic cycle and protects against cerebral malaria

BackgroundMalaria is a parasitic disease that compromises the human host. Currently, control of the Plasmodium falciparum burden is centered on artemisinin-based combination therapies. However, decreased sensitivity to artemisinin and derivatives has been reported, therefore it is important to identify new therapeutic strategies. MethodWe used human erythrocytes infected with P. falciparum and experimental cerebral malaria (ECM) animal model to assess the potential antimalarial effect of eugenol, a component of clove bud essential oil. ResultsPlasmodium falciparum cultures treated with increasing concentrations of eugenol reduced parasitemia in a dose-dependent manner, with IC50 of 532.42 ± 29.55 μM. This effect seems to be irreversible and maintained even in the presence of high parasitemia. The prominent effect of eugenol was detected in the evolution from schizont to ring forms, inducing important morphological changes, indicating a disruption in the development of the erythrocytic cycle. Aberrant structural modification was observed by electron microscopy, showing the separation of the two nuclear membrane leaflets as well as other subcellular membranes, such as from the digestive vacuole. Importantly, in vivo studies using ECM revealed a reduction in blood parasitemia and cerebral edema when mice were treated for 6 consecutive days upon infection. ConclusionsThese data suggest a potential effect of eugenol against Plasmodium sp. with an impact on cerebral malaria. General significanceOur results provide a rational basis for the use of eugenol in therapeutic strategies to the treatment of malaria.

The Role of Sex in Malaria-COVID19 Coinfection and Some Associated Factors in Rivers State, Nigeria.

Objectives Data on the coinfection of malaria and COVID-19 is highly limited especially in Africa due to the novel nature of the pandemic COVID-19. Malaria and COVID-19 share striking similarities in their symptoms. A cross-sectional randomized study was conducted to investigate the role of sex in the coinfection of malaria and COVID-19 as well as some associated factors in Rivers State, Nigeria. Methods Ethical approval was obtained from the Rivers State Health and Ethics Committee before the commencement of this study, and the study was conducted at the COVID-19 Treatment Center Medical Laboratory, Rivers State, Nigeria. Intravenous blood samples from three hundred randomly selected consenting study participants were examined for Plasmodium species using Giemsa microscopy, while pretested questionnaires were used to obtain data on sex, risk factors, and symptoms. All data generated were analyzed statistically using the Chi-square test with a P < 0.05 value considered significant. Results All study participants had Plasmodium species (100% prevalence) with varying parasite loads, and P. falciparum was the only species observed. Study participants (irrespective of sex) with low and high parasitaemia had the highest and least prevalence, respectively (P > 0.05). Male study participants experienced more symptoms than females (P > 0.05) except for sore throat which had an equal value among males and females. Travel history was the only risk factor that showed significant association with sex, and males had a higher value than females (P < 0.05). Conclusion Malaria and COVID-19 are major public health issues in Nigeria; more researches on these diseases especially in epidemiology, pathology, diagnosis, treatment, and vaccine production are vital.

Prevalence, intensity and some vector dynamics of malaria in Ogbaru local government area of Anambara State, Nigeria

A study on the prevalence, intensity and some vector dynamics of malaria was carried out in Ogbaru Local Government Area of Anambra State using standard parasitological and entomological techniques for rapid assessment of malaria infection, level of parasitaemia and morphological features of mosquitoes. The results showed an overall malaria RDT prevalence of 20% and community based prevalence of 13 (16.0%) and 22(24%) for Odekpe and Ogbakuba respectively. In Odekpe, the age range (1-7 years) had the highest prevalence while in Ogbakuba the highest prevalence was the age range 7-14 years. Overall, males had lower malaria prevalence (14.0%) than females (21.0%). The intensity of malaria infection from each of the communities revealed that both high (&gt;2000 - 250000parasites/µl) and medium (&gt;500-2000 parasites/µl) parasitaemia was more in Ogbakuba community. Two hundred and thirty (230) mosquitoes were collected. One hundred and four (45%) of the total mosquito population in the study were found to be unfed with blood meal, whereas 86(37%) and 40(17%) were freshly and previously fed respectively. One hundred and forty two (61.7%) of the mosquitoes appeared gravid against 88(38%) that were non-gravid. The mosquitoes encountered were Anopheles gambiae 76(33.04%), Anopheles funestus 86(37.39%), and Culex specie 68(29.56%). Malaria transmission and possibility of an ongoing transmission of other mosquito-borne diseases among residents in the study area should necessitate design for further studies that would explore the interactions of mosquito species and the diseases they transmit in co- endemic communities as well as effective methods for their control.

A large-scale survey of Theileria orientalis infection in grazing dairy heifers in Kyushu, Japan.

The objective of the present study was to investigate the prevalence of Theileria orientalis infection and the influence of this disease on dairy grazing heifers in Kyushu by monitoring red blood cell (RBC) indexes, and to evaluate the efficacy of diminazene diaceturate treatment of T. orientalis-infected animals. A monthly epidemiological survey was conducted for Holstein heifers, which were reared from 10 to 16 months of age on a large commercial dairy farm and grazed on eight independent grasslands from April to November, 2009. During the survey, a total of 2,803 blood samples were collected from the 891 grazing heifers, in which the prevalence of T. orientalis infection was 52.4%. Compared with the heifers before infection, heifers with high parasitemia (more than 100 parasites per 104 RBC) had significantly decreased RBC indexes, such as RBC count, hemoglobin concentration, and hematocrit (P<0.05), whereas heifers with low parasitemia (less than 100 parasites per 104 RBC) had similar RBC indexes as those before infection. Treatment with diminazene diaceturate had lower efficacy in heifers with high parasitemia than those with low parasitemia (40.7% and 73.2% became negative, respectively, P<0.05). In summary, T. orientalis infection is a potentially serious problem in Kyushu, and it is important to routinely implement control programs for heifers that are grazed on grasslands in this region.

Malaria Risk and Prevention in Asian Migrants to Angola.

The number of Asian migrants working in sub-Saharan developing countries like Angola has been increasing. Their malaria risk, prevention, and care-seeking practices have not been characterized. A cross-sectional survey was conducted in 733 Chinese and Southeast Asian migrants in Angola. Respondents were interviewed and provided blood samples. Samples were analyzed to detect Plasmodium antigen and characterize host anti-Plasmodium response. Positive samples were genotyped using the pfs47 marker. Most respondents (72%; 95% CI: 68-75) reported using bed nets, but less than 1% reported using chemoprophylaxis. Depending on the assay, 1-4% of respondents had evidence of active malaria infection. By contrast, 55% (95% CI: 52-59) were seropositive for Plasmodium antibodies. Most infections were Plasmodium falciparum, but infection and/or exposure to Plasmodium vivax and Plasmodium malariae was also detected. Seroprevalence by time in Angola showed most exposure occurred locally. One respondent had sufficiently high parasitemia for pfs47 genotyping, which showed that the infection was likely locally acquired despite recent travel to home country. Asian migrants to Angola are at substantial risk of malaria. Employers should consider enhanced malaria prevention programs, including chemoprophylaxis; embassies should encourage prevention practices. Angolan healthcare workers should be aware of high malaria exposure in Asian migrants.

Prevalence and Risk Factors of Asymptomatic Plasmodium Infection in Gondar Zuria District, Northwest Ethiopia.

BackgroundMalaria is one of the major public health problems worldwide. In Ethiopia, an increase in malaria incidence may be attributed to the presence of community-wide asymptomatic Plasmodium infection. This study aims to assess asymptomatic Plasmodium infection and associated factors in Gondar Zuria district, Northwest Ethiopia.MethodsA community-based cross-sectional study was conducted in Gondar Zuria district from May to June 2019. Angacha and Hamsafeg villages were randomly selected from Tachtseda and Hamsafeg kebeles, respectively. Fifty-three (53) households were selected using systematic random sampling to recruit a total of 251 study participants. Sociodemographic data were collected using structured questionnaires. Thin and thick blood films were prepared and examined for evidence of parasites. Data were entered and analyzed using SPSS version 23. The association between dependent (asymptomatic Plasmodium infection) and independent (sex, age group, family size and previous history of malaria) variables was explored using bivariate and multivariate logistic regression. Statistically significant association was declared at a P-value of <0.05.ResultsA total of 251 individuals were tested, of whom 53.4% were females and 33.5% were above the age of 30 years. The prevalence of asymptomatic Plasmodium infection was 12%. The highest prevalence of malaria was observed in females (6.4%) and among the age group 15–29 years (4.4%). The majority (70%) of study participants had <500 parasites/μL of blood. A high parasitemia level (ie ≥1000 parasites/μL of blood) was observed in the age group 15–29 years. Age group, bed net usage and previous history of malaria were significantly associated with asymptomatic Plasmodium infection (P<0.05).ConclusionAsymptomatic Plasmodium infection remains an important public health problem in the study area. Further studies using more sensitive diagnostic methods are required to scale up the eradication and control program of malaria.

Circulating Trypanosoma cruzi load and major cardiovascular outcomes in patients with chronic Chagas cardiomyopathy: a prospective cohort study.

To analyse the effect of parasite load assessed by quantitative reverse transcription PCR (RT-qPCR) in serum on the prognosis of patients with chronic Chagas cardiomyopathy (CCM) after a 2-year follow-up. Prospective cohort study conducted between 2015 and 2017. One hundred patients with CCM were included. Basal parasitaemia levels of Trypanosoma cruzi (T.cruzi) were measured using a quantitative polymerase chain reaction (qPCR) test. The primary composite outcome (CO) was all-cause mortality, cardiac transplantation and implantation of a left ventricular assist device. Secondary outcomes were the baseline levels of serum biomarkers and echocardiographic variables. After a 2years of follow-up, the primary CO rate was 16%. A positive qPCR was not associated with a higher risk of the CO. However, when parasitaemia was evaluated by comparing tertiles (tertile 1: undetectable parasitaemia, tertile 2: low parasitaemia and tertile 3: high parasitaemia), a higher risk of the CO (HR 3.66; 95% CI 1.11-12.21) was evidenced in tertile 2. Moreover, patients in tertile 2 had significantly higher levels of high-sensitivity troponin T and cystatin C and more frequently exhibited an ejection fraction <50%. Low parasitaemia was associated with severity markers of myocardial injury and a higher risk of the composite outcome when compared with undetectable parasitaemia. This finding could be hypothetically explained by a more vigorous immune response in patients with low parasitaemia that could decrease T.cruzi load more efficiently, but be associated with increased myocardial damage. Additional studies with a larger number of patients and cytokine measurement are required to support this hypothesis.

Bacteraemia, Malaria, and Case Fatality Among Children Hospitalized With Fever in Dar es Salaam, Tanzania.

BackgroundFebrile illness is the commonest cause of hospitalization in children <5 years in sub-Saharan Africa, and bacterial bloodstream infections and malaria are major causes of death.MethodsFrom March 2017 to July 2018, we enrolled 2,226 children aged 0–5 years hospitalized due to fever in four major public hospitals of Dar es Salaam, namely, Amana, Temeke, and Mwananyamala Regional Hospitals and Muhimbili National Hospital. We recorded social demographic and clinical data, and we performed blood-culture and HIV-antibody testing. We used qPCR to quantify Plasmodium falciparum parasitaemia and Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) to identify bacterial isolates. Disk diffusion method was used for antimicrobial susceptibility testing.ResultsNineteen percent of the children (426/2,226) had pathogens detected from blood. Eleven percent (236/2,226) of the children had bacteraemia/fungaemia and 10% (204/2,063) had P. falciparum malaria. Ten children had concomitant malaria and bacteraemia. Gram-negative bacteria (64%) were more frequent than Gram-positive (32%) and fungi (4%). Over 50% of Gram-negative bacteria were extended-spectrum beta-lactamase (ESBL) producers and multidrug resistant. Methicillin resistant Staphylococcus aureus (MRSA) was found in 11/42 (26.2%). The most severe form of clinical malaria was associated with high parasitaemia (>four million genomes/μL) of P. falciparum in plasma. Overall, in-hospital death was 4% (89/2,146), and it was higher in children with bacteraemia (8%, 18/227) than malaria (2%, 4/194, p = 0.007). Risk factors for death were bacteraemia (p = 0.03), unconsciousness at admission (p < 0.001), and admission at a tertiary hospital (p = 0.003).ConclusionCompared to previous studies in this region, our study showed a reduction in malaria prevalence, a decrease in in-hospital mortality, and an increase in antimicrobial resistance (AMR) including ESBLs and multidrug resistance. An increase of AMR highlights the importance of continued strengthening of diagnostic capability and antimicrobial stewardship programs. We also found malaria and bacteraemia contributed equally in causing febrile illness, but bacteraemia caused higher in-hospital death. The most severe form of clinical malaria was associated with P. falciparum parasitaemia.

A modified two-color flow cytometry assay to quantify in-vitro reinvasion and determine invasion phenotypes at low Plasmodium falciparum parasitemia

Invasion of human red blood cells (RBCs) by Plasmodium parasites is a crucial yet poorly characterised phenotype. Two-color flow cytometry (2cFCM) promises to be a very sensitive and high throughput method for phenotyping parasite invasion. However, current protocols require high (~1.0%) parasitemia for assay set-up and need to be adapted for low parasitemia samples, which are becoming increasingly common in low transmission settings. Background fluorescence from nuclei-containing uninfected RBCs and high autologous reinvasion rates (merozoite invasion of donor uninfected RBCs present at 50% assay volume) are some of the limitations to the method's sensitivity to enumerate low parasitemia (<0.5%) with nucleic acid-based stains. Here, we describe modifications for plating unlabeled donor to labeled target RBCs per assay well and for gating parasitemia, that produces accurate quantifications of low reinvasion parasitemia. Plasmodium falciparum 3D7, Dd2 and field isolates at various low and high parasitemia (0.05%–2.0%) were used to set-up SyBr Green 1-based 2cFCM invasion assays. Target RBCs were labeled with CTFR proliferation dye. We show that this dye combination allowed for efficient parasite invasion into target RBCs and that a 1:3 ratio of unlabeled to labeled RBCs per assay greatly skewed autologous reinvasion (p < 0.001). Accuracy of quantifying reinvasion was limited to an assay parasitemia of 0.02% with minimal background interference. Invasion inhibition by enzymatic treatments increased averagely by 10% (p<0.05) across the entire parasitemia range. The effect was greater for samples with <0.5% parasitemia. Overall, a more sensitive method for phenotyping invasion of low P. falciparum parasitemia is described.

Effects of forest structure on the interaction between avian hosts, dipteran vectors and haemosporidian parasites

BackgroundForest habitats are important biodiversity refuges for a wide variety of bird species. Parasitism may modulate host species presence and abundance, and parasite effects can change according to forest management practices. Such processes are not well studied in vector-borne avian haemosporidians. We analyzed the effects of forest management on bird-dipteran-haemosporidian interactions, using seven common bird species in managed and unmanaged beech forest habitats in northeastern Germany. We assumed that forest structural heterogeneity affects parasite population parameters in avian hosts (i.e., prevalence and parasitemia), through its effect on the condition of the avian host but also through varying vector abundances.ResultsParasite prevalence was high (about 80%) and homogeneous across different beech forest categories (i.e., young, old, unmanaged) and for all bird species, except Erithacus rubecula (35%). Parasitemia varied across bird species but not across forest categories within each avian species (lowest parasitemia were found in E. rubecula, Turdus merula, and Turdus philomelos). In our study system, we found that vector abundance was not the main driver of parasite dynamics. We found that forest structure affects parasite infection probability directly and potentially host condition via available resources that have to be used either to combat infections (i.e., high parasitemia) or to maintain a good body condition.ConclusionsThe effects of each of the predictors were bird species-specific, and we found that Diptera vectors were not the foremost influence in our host-vector-parasite system. Effects of forest habitat variables indicated that for most bird species in this study, habitat regulation of infection probability was more likely (i.e., E. rubecula, Fringilla coelebs, Sylvia atricapilla), whereas for Parus major habitat characteristics impacted first individuals' body condition and subsequently the probability of infection. Our findings emphasize the need of species-specific analyses and to use continuous forest structural parameters (e.g., the proportion of gap, south facing aspect) to better understand habitat and land use effects on host-vector-parasite dynamics.

Detection of remaining Plasmodium DNA and gametocytes during follow up after curative malaria treatment among returned travellers in Norway

BackgroundPCR can be positive weeks after effective malaria treatment, potentially leading to over diagnose of recrudescence and re-infections. The DNA detected by PCR post-treatment might stem from residuals of destroyed asexual parasites, or from live gametocytes. The objective of this clinical observational study was to describe the presence of positive PCR for Plasmodium falciparum and Plasmodium vivax in follow-up samples post-treatment from returned travellers, and the proportion of positive PCR due to gametocytes.MethodsWhole blood was collected during hospitalization and outpatient routine follow-up from 13 patients with imported malaria. DNA was extracted applying QIAamp DNA Blood Mini Kit, while mRNA was collected and extracted applying PAXgene Blood RNA Tubes and Kit. All DNA samples (N = 25) were analysed with a genus-specific cytb real-time SYBR PCR, and P. falciparum DNA samples (N = 22) were also analysed with a falciparum-specific varATS real-time TaqMan PCR. All the mRNA samples (N = 18) were analysed with both a genus-specific 18S rRNA RT-PCR and a gametocyte-specific Pfs25 (P. falciparum)/Pvs25 (P. vivax) RT-PCR.ResultsLatest samples were collected at day 1 (n = 2) and from day 11–54 (n = 11) after treatment. Genus DNA cytb PCR was positive up to 49 days after effective treatment, and 18S rRNA transcripts from active P. falciparum parasites were detectable for at least 11 days. Gametocyte-specific mRNA was detected at latest only two days after treatment. Among six patients with late positive PCR for P. falciparum, four had high parasitaemia at admittance (6–30%), while two had parasitaemia < 2%. Late detection of P. vivax was not found by any of the PCR methods.ConclusionsDNA-based PCR can be positive up to at least seven weeks after curative malaria treatment, potentially leading to over-diagnose of recrudescence and re-infections. Based on the observations in this study, it is unclear if the DNA origins from residuals of destroyed parasites or live gametocytes, warranting further investigations.

Infection dynamics of Theileria equi in carrier horses is associated with management and tick exposure

The tick-borne equine hemoparasite, Theileria equi, is endemic in many parts of the world where prevalence may be high, and most infected horses are apparently healthy but serve as life-long carriers. To determine the factors that affect T. equi dynamics, we followed parasitic loads in apparently healthy horses at four time points during one year. A total of 1094 blood samples were collected from 395 horses, along with ticks and demographic and clinical data. Infection and load of T. equi were tested by PCR and qPCR, and for the spring dataset, infection was also tested serologically by IFAT (n = 268). Theileria equi was molecularly detected in 64.8 % of the horses. The agreement between molecular and serological results was 79.8 % (K > 0.674) and positively correlated with parasitic load. Infection was associated with pale mucus membranes, lower packed cell volume and higher total solids (all P < 0.001), although these changes had only minor clinical importance. While parasitic loads in qPCR-positive samples (n = 561) were generally low (mean = 7.9−10−4% parasitized erythrocytes), younger horses showed higher loads, possibly suggesting development of immunity. Infection and parasitic load were associated with housing management and tick exposure, illustrating different patterns of exposure. Endemic stability is suggested in pasture farms with constant exposure to ticks, where parasite prevalence was high (96 %) and associated with T. equi 18S rRNA genotype D, low parasitemia and high antibody titers. Endemic instability can be suggested in case were horses are kept in paddocks (prevalence = 49 %) with intermittent exposure to ticks, where infection was associated with high parasitemia when ticks were present. A steady state is suggested in stabled horses (prevalence = 46 %), with no exposure to ticks; where infection was associated with genotype A, low parasitemia and low antibody titers. The ability to identify different risk groups within endemic areas may improve the administration of suitable treatment and control practices in an effort to reduce the risk of clinical disease.

Determinants of geospatial distribution of parasitaemia among patients infected with Plasmodium falciparum malaria in Ondo State, Southwest, Nigeria

Malaria is a disease caused by Plasmodium parasites which is transmitted by female Anopheles mosquitoes. It remains one of the most deadly diseases globally and especially in the tropical nations of the world. In the clinical setting, the level of parasitaemia is useful as one of the criteria in defining “severe Plasmodium falciparum malaria” and to monitor the effect of anti-malarial therapy. Mapping is a known vital tool in the control and elimination of malaria globally. In this study, blood samples were collected from 415 malaria infected patients in the outpatient department of 10 randomly selected government hospitals. Coordinates of the patients’ address were taken, geocoding, mapping and cartographic display were carried out. Thin and thick blood smear preparations and microscopy were conducted on the blood samples collected from outpatients attending some selected government hospitals and percentage parasitaemia were determined. Ondo North Senatorial District had the highest mean parasitaemia of 1.06% while Ondo South had the least mean parasitaemia (0.89%). The risk map revealed that majority of patients in Ondo North 26.05% (31/119) and few in Ondo Central 12.73% (21/165) senatorial district had high malaria burden with high parasitaemia (2.62 to 5.1% parasitaemia). Based on the malaria map developed, this study could be used as guide in monitoring the efficacy of antimalarial therapy and provide information for malaria control intervention in Ondo State.

Diagnostics and Spread of SARS-CoV-2 in Western Africa: An Observational Laboratory-Based Study from Benin

Background: Information on severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spread in Africa is limited by fragile surveillance systems and insufficient diagnostic capacity. Methods: We assessed the coronavirus disease-19 (COVID-19)-related diagnostic workload in Benin, Western Africa, characterized SARS-CoV-2 genomes from 12 acute cases of COVID-19, used those together with public data to estimate SARS-CoV-2 transmission dynamics in a Bayesian framework, validated a widely used diagnostic dual target RT-PCR kit donated to African countries, and conducted serological analyses in 68 sera from confirmed COVID-19 cases and from febrile patients sampled before the predicted SARS-CoV-2 introduction. Findings: We found a 15-fold increase in the monthly laboratory workload due to COVID-19. Genomic surveillance showed introductions of three distinct SARS-CoV-2 lineages. SARS-CoV-2 genome-based analyses yielded an R0 estimate of 4.4 (95% confidence interval: 2.0-7.7), suggesting intense spread of SARS-CoV-2 in Africa. RT-PCR-based tests were highly sensitive but showed variation of internal controls and between diagnostic targets. Commercially available SARS-CoV-2 ELISAs showed up to 25% false-positive results depending on antigen and antibody types, likely due to unspecific antibody responses elicited by acute malaria according to lack of SARS-CoV-2-specific neutralizing antibody responses and relatively higher parasitemia in those sera. Interpretation: We confirm an overload of the diagnostic capacity in Benin and provide baseline information on the usability of genome-based surveillance in resource-limited settings. Sero-epidemiological studies needed to assess SARS-CoV-2 spread may be put at stake by low specificity of tests in tropical settings globally. The increasing diagnostic challenges demand continuous support of national and supranational African stakeholders. Funding: This work was supported by the Deutsche Gesellschaft fur Internationale Zusammenarbeit (GIZ) GmbH. Declaration of Interests: The authors declare no conflict of interests. Ethics Approval Statement: This study was approved by the ethics committee of the Ministry of Health (Arrete 2020 No. 030/MS/DC/SGM/DNSP/CJ/SA/027SGG2020) and followed the Declaration of Helsinki. Written consent was obtained from all the patients participating in the study.

Insulin signalling in RBC is responsible for growth stimulation of malaria parasite in diabetes patients

A cross-talk between diabetes and malaria within-host is well established. Diabetes is associated with modulation of the immune system, impairment of the healing process and to disturb the host metabolism to contribute towards propagation of parasite infection. Glucose metabolism in host is maintained by insulin and RBC has 2000 insulin receptor present on plasma membrane. These receptors are robust to relay down-stream signaling in RBCs but role of intracellular signaling in parasite growth is not been explored. The malaria parasite treated with insulin (100 ng/ml) is giving stimulation in parasite growth. The effect is lasting for several generations resulting into high parasitemia. Insulin signaling is phosphorylating protein in infected RBCs and level is high in parasite RBCs compared to uninfected RBCs. It is phosphorylating Spectrin-(α/β), Band-4.2, Ankyrin and the other proteins of RBC cytoskeleton. It in-turn induces enhanced glucose uptake inside infected RBCs. There is a high level of infection of normal RBCs by merozoites. In summary, insulin and glucose metabolism plays a crucial role in parasite propagation, disease severity and need consideration while treating patients.

Pregnancy outcomes and risk of placental malaria after artemisinin-based and quinine-based treatment for uncomplicated falciparum malaria in pregnancy: a WorldWide Antimalarial Resistance Network systematic review and individual patient data meta-analysis

BackgroundMalaria in pregnancy, including asymptomatic infection, has a detrimental impact on foetal development. Individual patient data (IPD) meta-analysis was conducted to compare the association between antimalarial treatments and adverse pregnancy outcomes, including placental malaria, accompanied with the gestational age at diagnosis of uncomplicated falciparum malaria infection.MethodsA systematic review and one-stage IPD meta-analysis of studies assessing the efficacy of artemisinin-based and quinine-based treatments for patent microscopic uncomplicated falciparum malaria infection (hereinafter uncomplicated falciparum malaria) in pregnancy was conducted. The risks of stillbirth (pregnancy loss at ≥ 28.0 weeks of gestation), moderate to late preterm birth (PTB, live birth between 32.0 and < 37.0 weeks), small for gestational age (SGA, birthweight of < 10th percentile), and placental malaria (defined as deposition of malaria pigment in the placenta with or without parasites) after different treatments of uncomplicated falciparum malaria were assessed by mixed-effects logistic regression, using artemether-lumefantrine, the most used antimalarial, as the reference standard. Registration PROSPERO: CRD42018104013.ResultsOf the 22 eligible studies (n = 5015), IPD from16 studies were shared, representing 95.0% (n = 4765) of the women enrolled in literature. Malaria treatment in this pooled analysis mostly occurred in the second (68.4%, 3064/4501) or third trimester (31.6%, 1421/4501), with gestational age confirmed by ultrasound in 91.5% (4120/4503). Quinine (n = 184) and five commonly used artemisinin-based combination therapies (ACTs) were included: artemether-lumefantrine (n = 1087), artesunate-amodiaquine (n = 775), artesunate-mefloquine (n = 965), and dihydroartemisinin-piperaquine (n = 837). The overall pooled proportion of stillbirth was 1.1% (84/4361), PTB 10.0% (619/4131), SGA 32.3% (1007/3707), and placental malaria 80.1% (2543/3035), and there were no significant differences of considered outcomes by ACT. Higher parasitaemia before treatment was associated with a higher risk of SGA (adjusted odds ratio [aOR] 1.14 per 10-fold increase, 95% confidence interval [CI] 1.03 to 1.26, p = 0.009) and deposition of malaria pigment in the placenta (aOR 1.67 per 10-fold increase, 95% CI 1.42 to 1.96, p < 0.001).ConclusionsThe risks of stillbirth, PTB, SGA, and placental malaria were not different between the commonly used ACTs. The risk of SGA was high among pregnant women infected with falciparum malaria despite treatment with highly effective drugs. Reduction of malaria-associated adverse birth outcomes requires effective prevention in pregnant women.

Changes in Liver Function Enzymes in Plasmodium falciparum Infected Malaria Patients in Ajeromi General Hospital, Lagos, Nigeria

Objective: This study is to determine the changes in liver function enzymes in P. falciparum-infected patients in Ajeromi ifelodun area of Lagos, Nigeria by examining changes in some liver enzymes: Aspartate Transaminase (AST), Alanine Transaminase (ALT) and Alkaline phosphatase (ALP) obtained from newly diagnosed cases of malarial infection yet to be treated.&#x0D; Study Design: Seventy (70) human subjects comprising of 50 P. falciparum malarial infected and 20 non-infected (control) subjects between 10-60 years were selected for this study. Malaria positive subjects were divided into three groups based on the number of parasite per μl. Those that had parasitaemia below 10,000 parasites per μl were considered a mild infection, those that had parasitaemia above 10,000 parasites per μl were considered severe infections and those with parasitaemia below 1,000 parasites per μl were considered a low infection. RDT test and microscopy was carried out to ascertain the presence of P.falciparum. They were grouped based on age group, sex and level of parasitaemia.&#x0D; Materials and Methods: Blood samples were collected for the determination of P. falciparum, level of parasitaemia and liver function enzymes Aspartate Transaminase (AST), Alanine Transaminase (ALT) and Alkaline Phosphatase (ALP). P. falciparum was determined by Rapid Diagnostic Test (RDT) and microscopy.&#x0D; Results: There was a significant increase (P &lt; 0.001) in the mean level of serum Aspartate Transaminase (AST), Alanine Transaminase (ALT) and a significant decrease in the mean level of alkaline phosphatase (ALP) in the P. falciparum-infected patients compared to the control subjects. AST level was found to be significantly higher (P&lt;0.001) among age group (51- above) in the P. falciparum patients and significantly lower among age group (10-20) in the control subjects when compared to other age groups.&#x0D; ALT level was significantly higher (P &lt; 0.001) among age group (51- above) in the P. falciparum patients and significantly lower among age group (41-50) in the control subjects when compared to other age groups. ALP level was significantly higher (P &lt; 0.001) among age group (41-50) in the P. falciparum patients and significantly lower among age group (10-20) in the control subjects when compared to other age groups. AST and ALT were found to be significantly higher (P &lt; 0.001) in the high parasitaemia group when compared to the low and moderate parasitaemia group and they were also significantly higher in the moderate parasitaemia group than in the low parasitaemia group.ALP was significantly higher (P &lt; 0.001) in the moderate parasitaemia group when compared to the low and high parasitaemia group and they were only marginally lower in the high than in the low parasitaemia group.&#x0D; Conclusion: There was an elevated level of liver function enzymes in the P. falciparum patients than in the control subjects. This study shows that high parasitaemic patients are at greater risk of hepatic damage than the low parasitaemic group, hence early diagnosis and treatment of malaria are highly encouraged.

Alterations of cardiac and renal biomarkers in horses naturally infected with theileria equi

Equine theileriosis due to Theileria equi is probably the most widespread and pathogenic disease of equines, which comes with major cardiac and renal complications. This study was undertaken to investigate the biomarkers of cardiac and renal functions in horses infected with T. equi and determine the association between these parameters and the level of parasitemia. Giemsa-stained blood smears from 300 horses with ages of 3–4 years old were examined for detection of T. equi on erythrocytes. Moreover, multiplex PCR was employed for confirmation of the diagnosis in the 28 positive cases. Based on the rate of red blood cell infection, the infected animals were subdivided into horses with low (n = 9), moderate (n = 13) and high (n = 6) parasitemia. The concentrations of urea, creatinine, cystatin-C, cardiac troponin I (cTn-I), homocysteine (Hcy), myocardial fractions of creatine kinase (CK-MB) and d-dimer were determined in control (healthy) horses (n = 20) and the infected animals. The results revealed that both the renal (urea, creatinine and cystatin-C) and the cardiac (cTn-I, Hcy, CK-MB and d-dimer) biomarkers increased in a parasitemia burden-dependent pattern. However, urea, creatinine, cTn-I and d-dimer levels were not significantly influenced in the horses infected with low rate (<1 %) of parasitemia (p> 0.05). Moreover, all of the biomarkers were significantly and positively associated with the parasitemia (R2> 0.5). In conclusion, T. equi infection was related to cardiac and renal complications evidenced by increase in the levels of biomarkers and evaluation of these indices may have promise for early diagnosis of the complications.