Hyperimmune malarial splenomegaly in a malaria-endemic area of southwest Burkina Faso: case of Bobo-Dioulasso.

INTRODUCTION: Hyperreactive malarial splenomegaly (HMS) is one of the main causes of massive splenomegaly in malaria-endemic zones. Diagnosis is often challenging in Bobo-Dioulasso. This study aimed to describe the clinical and socio-demographic profile, and the reasons for delay in the diagnosis of HMS cases recorded in the Medicine and Medical Specialties wards of Souro Sanou Teaching hospital. METHODS: A retrospective descriptive study was conducted from August 2022 by focusing on HMS cases diagnosed in the Infectious Diseases and Clinical Hematology wards of Souro Sanou Teaching Hospital. RESULTS: Overall, 65 patients met our inclusion criteria over the 12-year period. Burkinabe nationals and have been residing in Burkina Faso since their birth. 79% (79%) of the patients were seen for medical consultation with the reason for consultation being a voluminous mass in the left hypochondrium. Indigence, self-medication, and lack of information were essential elements in late diagnosis of HMS in Bobo-Dioulasso. All patients were treated with a single tablet of Artemether (80 mg) and Lumefantrine (480 mg) in the morning and evening for 3 days, followed by sulfadoxine-pyrimethamine per week. Nine months later, patients were clinically asymptomatic. CONCLUSION: This study provides a database on hyperreactive malarial splenomegaly (HMS) in the south-west region of Burkina Faso. Rapid and accurate diagnosis of the disease and appropriate use of effective antimalarial drugs would significantly reduce the burden of HMS in Sub-Saharan African countries.

Elevated Inflammation Associated with Markers of Neutrophil Function and Gastrointestinal Disruption in Pilot Study of Plasmodium fragile Co-Infection of ART-Treated SIVmac239+ Rhesus Macaques.

Human immunodeficiency virus (HIV) and malaria, caused by infection with Plasmodium spp., are endemic in similar geographical locations. As a result, there is high potential for HIV/Plasmodium co-infection, which increases the pathology of both diseases. However, the immunological mechanisms underlying the exacerbated disease pathology observed in co-infected individuals are poorly understood. Moreover, there is limited data available on the impact of Plasmodium co-infection on antiretroviral (ART)-treated HIV infection. Here, we used the rhesus macaque (RM) model to conduct a pilot study to establish a model of Plasmodium fragile co-infection during ART-treated simian immunodeficiency virus (SIV) infection, and to begin to characterize the immunopathogenic effect of co-infection in the context of ART. We observed that P. fragile co-infection resulted in parasitemia and anemia, as well as persistently detectable viral loads (VLs) and decreased absolute CD4+ T-cell counts despite daily ART treatment. Notably, P. fragile co-infection was associated with increased levels of inflammatory cytokines, including monocyte chemoattractant protein 1 (MCP-1). P. fragile co-infection was also associated with increased levels of neutrophil elastase, a plasma marker of neutrophil extracellular trap (NET) formation, but significant decreases in markers of neutrophil degranulation, potentially indicating a shift in the neutrophil functionality during co-infection. Finally, we characterized the levels of plasma markers of gastrointestinal (GI) barrier permeability and microbial translocation and observed significant correlations between indicators of GI dysfunction, clinical markers of SIV and Plasmodium infection, and neutrophil frequency and function. Taken together, these pilot data verify the utility of using the RM model to examine ART-treated SIV/P. fragile co-infection, and indicate that neutrophil-driven inflammation and GI dysfunction may underlie heightened SIV/P. fragile co-infection pathogenesis.

Not all severe malaria cases are severe: Is it time to redefine severity criteria for malaria in non-endemic regions?

BACKGROUND: The current definition of severe malaria in non-endemic areas follows WHO criteria, which mainly target children in malaria-endemic areas, potentially misclassifying cases in non-endemic regions. We assessed the performance of a modified severe malaria classification criteria within our patient cohort. METHODS: A cohort study of patients managed for malaria in a non-endemic setting (2005-2023) was analyzed. We classified patients into severe malaria (SM) using WHO 2013 criteria except for hyperparasitemia, where 2 % threshold was applied. Patients with SM were distinguished as very severe malaria (VSM) when presenting at least one of the following conditions: parasitemia >10 %, pulmonary edema, impaired consciousness, seizures, renal failure, metabolic acidosis or hyperlactatemia, shock or hypoglycemia. In patients with SM and no criteria for VSM, less severe malaria (LSM) was defined by: 2-10 % parasitemia, hyperbilirubinemia, prostration, anemia or minor bleeding. The primary composite outcome was death or the need for a life-saving intervention, as analyzed in the three comparative groups. Secondary outcome was the prevalence of co-infections. RESULTS: Among 506 patients with malaria, 176 (34.8 %) presented with SM. A total of 37 (7.3 %) patients developed a life-threatening condition, namely death (n = 4) and/or the need for life-saving interventions (n = 34). All fatalities and 33 out of the 34 life-saving interventions occurred in the VSM group. Patients in LSM group did not develop any life-threatening conditions. As to co-infections, 28 (5.5 %) patients had a community-acquired co-infection, with no differences between groups (p = 0.763). CONCLUSIONS: Severity criteria definitions would benefit from a review when assessing patients with malaria in non-endemic areas. Within the spectrum of SM, patients reclassified as LSM have a low risk of developing a life-threatening condition and present low co-infection incidence and could benefit from management out of intensive care units and a restrictive use of empirical antibiotics.

Malaria and typhoid fever co-infection: a retrospective analysis of University Hospital records in Nigeria.

BACKGROUND: Studies have long documented the presence of malaria and typhoid fever in sub-Saharan Africa (SSA). However, studies on these diseases have primarily concentrated on rural settings, neglecting the potential impact on urban areas. This knowledge gap hinders effective surveillance and intervention strategies. To bridge this gap, this study investigated the prevalence of malaria and typhoid co-infections in an urban environment. METHODS: This study, conducted at Lead City University Hospital in Ibadan, Nigeria (West Africa's largest metropolis), analysed medical records of over 3195 patients seen between April and June 2023. Descriptive statistics and chi-square tests were used to understand how these co-infections were distributed across different age and gender groups. RESULTS: The prevalence of co-infection peaked in May (9.7%), followed by June (8.9%) and April (5.7%). Notably, children aged 6-12 years exhibited the highest co-infection rate (18.5%), while those under five had the lowest (6.3%). Gender analysis indicated a slight difference, with 8.8% of females and 7.1% of males co-infected. Malaria prevalence was highest at the beginning of the rainy season and significantly decreased over time. Conversely, typhoid fever displayed the opposite trend, increasing with the rainy season. Children under five years old were most susceptible to malaria, while typhoid fever predominantly affected adults over 25 years old, with prevalence decreasing significantly with age. CONCLUSION: This study sheds light on the previously overlooked risk of malaria and typhoid co-infections in urban settings. These findings highlight the need for enhanced surveillance and targeted public health interventions, particularly for vulnerable groups like young children during peak transmission seasons.

Prevalence of Plasmodium and Soil-Transmitted Helminth Coinfection and Associated Factors among Malaria-Suspected Patients Attending Shewa Robit Health Center, North-Central Ethiopia.

Plasmodium and soil-transmitted helminth (STH) coinfection is a major public health problem in developing countries. Its prevalence and associated factors are poorly addressed in the available research. Therefore, this study aimed to assess Plasmodium-STH coinfection prevalence and associated factors among malaria-suspected patients attending Shewa Robit Health Center, north-central Ethiopia. A cross-sectional study was conducted among 379 malaria-suspected patients attending Shewa Robit Health Center from April to May 2023. Stool and blood samples were collected from each participant. Plasmodium and STHs were detected from blood and stool samples by using blood film and the Kato-Katz method, respectively. Data were entered into Epi Info version 7 and analyzed by SPSS version 26. Descriptive statistics were used to compute Plasmodium-STH coinfection. Logistic regression was used to identify associated factors. Variables with a P-value <0.05 were considered statistically significant. Among the study participants, 27.9%, 20.3%, and 13.4% were positive for Plasmodium, STHs, and Plasmodium-STH coinfection, respectively. The prevalence of Plasmodium-Ascaris lumbricoides coinfection was high (7.6%). Unavailability of insecticide-treated bed nets (ITNs), improper use of ITNs, absence of indoor residual spraying, presence of stagnant water, and previous malaria infection were significantly associated (P <0.01) with Plasmodium infection. Being illiterate, using an unimproved latrine, having an untrimmed fingernail, and practicing open defecation were also significantly associated (P <0.03), with STH infection. Being male, illiterate, and living in rural areas were significantly associated (P <0.03) with Plasmodium-STH coinfection. The prevalence of Plasmodium-STH coinfection was high in malaria-endemic areas. Therefore, malaria-suspected cases should be checked for STH infection.

Worldwide distribution, symptoms and diagnosis of the coinfections between malaria and arboviral diseases: a systematic review.

The coinfection between malaria (ML) and arboviral diseases represents a major global public health problem, particularly in tropical and subtropical countries. Despite its relevance, this topic is still insufficiently discussed in the current literature. Here, we aimed to investigate the worldwide distribution, symptoms, and diagnosis during coinfection between ML and arboviral diseases. We conducted a systematic review following the Preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement and assessed the selection and eligibility criteria, created and diagrammed maps, and analysed major symptoms with 95% confidence intervals (CI) using prevalence ratio and effect size, also performing latent class analysis. A total of 85,485 studies were retrieved, of which 56 were included: 57.14% in Asia, 25% in Africa, 14.30% in South America, and 3.56% in Europe. A total of 746 individuals were reported to be coinfected with Plasmodium and arbovirus. Concurrent ML, Dengue (DEN), Chikungunya (CHIK), and Zika (ZIK) patients are more likely to present headache and skin rash. Regarding diagnosis, 58,253 were made, of which 38,176 were positive (ML and at least one arboviral disease). The magnitude of these pathogens' coexistence points out the pressing need for improvements in public health policies towards diagnosis and prevention of both diseases, especially in endemic areas.

Hypertension Increases Susceptibility to Experimental Malaria in Mice.

Global prevalence of hypertension is on the rise, burdening healthcare, especially in developing countries where infectious diseases, such as malaria, are also rampant. Whether hypertension could predispose or increase susceptibility to malaria, however, has not been extensively explored. Previously, we reported that hypertension is associated with abnormal red blood cell (RBC) physiology and anemia. Since RBC are target host cells for malarial parasite, Plasmodium, we hypothesized that hypertensive patients with abnormal RBC physiology are at greater risk or susceptibility to Plasmodium infection. To test this hypothesis, normotensive (BPN/3J) and hypertensive (BPH/2J) mice were characterized for their RBC physiology and subsequently infected with Plasmodium yoelii (P. yoelii), a murine-specific non-lethal strain. When compared to BPN mice, BPH mice displayed microcytic anemia with RBC highly resistant to osmotic hemolysis. Further, BPH RBC exhibited greater membrane rigidity and an altered lipid composition, as evidenced by higher levels of phospholipids and saturated fatty acid, such as stearate (C18:0), along with lower levels of polyunsaturated fatty acid like arachidonate (C20:4). Moreover, BPH mice had significantly greater circulating Ter119+ CD71+ reticulocytes, or immature RBC, prone to P. yoelii infection. Upon infection with P. yoelii, BPH mice experienced significant body weight loss accompanied by sustained parasitemia, indices of anemia, and substantial increase in systemic pro-inflammatory mediators, compared to BPN mice, indicating that BPH mice were incompetent to clear P. yoelii infection. Collectively, these data demonstrate that aberrant RBC physiology observed in hypertensive BPH mice contributes to an increased susceptibility to P. yoelii infection and malaria-associated pathology.

Aspecific binding of anti-NK1.1 antibodies on myeloid cells in an experimental model for malaria-associated acute respiratory distress syndrome.

BACKGROUND: Conventional natural killer (cNK) cells play an important role in the innate immune response by directly killing infected and malignant cells and by producing pro- and anti-inflammatory cytokines. Studies on their role in malaria and its complications have resulted in conflicting results. METHODS: Using the commonly used anti-NK1.1 depletion antibodies (PK136) in an in-house optimized experimental model for malaria-associated acute respiratory distress syndrome (MA-ARDS), the role of cNK cells was investigated. Moreover, flow cytometry was performed to characterize different NK cell populations. RESULTS: While cNK cells were found to be dispensable in the development of MA-ARDS, the appearance of a NK1.1+ cell population was observed in the lungs upon infection despite depletion with anti-NK1.1. Detailed characterization of the unknown population revealed that this population consisted of a mixture of monocytes and macrophages that bind the anti-NK1.1 antibody in an aspecific way. This aspecific binding may occur via Fcγ receptors, such as FcγR4. In contrast, in vivo depletion using anti-NK1.1 antibodies was proved to be specific for cNK cells. CONCLUSION: cNK cells are dispensable in the development of experimental MA-ARDS. Moreover, careful flow cytometric analysis, with a critical mindset in relation to potential aspecific binding despite the use of commercially available Fc blocking reagents, is critical to avoid misinterpretation of the results.

Seroprevalence study of dengue-malaria coinfection in an East-Cameroonian public hospital: A comparison between malarial and non-malarial groups.

BACKGROUNDS OBJECTIVES: Recent research in Cameroon reported several occurrences of dengue in urban settings, but concurrent dengue-malaria infection has received less attention, particularly in the East region. METHODS: A two-month cross-sectional and comparative research was performed at Bertoua Regional Hospital which included 50 malaria-positive participants and 90 non-malaria subjects. Participants were selected and provided with a questionnaire to collect sociodemographic data. Blood samples were collected and tested for dengue infection and hematological parameters were assessed. RESULTS: Dengue fever was found in 14% of malarial patients vs 66.66% of controls. Secondary dengue infection was more prevalent in malarial patients than in non-malarial patients. Gender, age, and place of residence were positively correlated to dengue seropositivity. Platelets were substantially lower (P<0.001) in the malarial group than in the non-malarial group. INTERPRETATION CONCLUSION: In the study, coinfected patients were found to be more vulnerable to dengue, emphasizing the importance of epidemiological surveillance.

Changing etiological spectrum of acute liver failure.

BACKGROUND AND OBJECTIVES: Acute liver failure (ALF) is an uncommon but potentially dramatic syndrome characterized by massive hepatic necrosis and has a very high mortality rate of 50% to 75% without liver transplantation. This study is aimed at analyzing the etiological spectrum of ALF patients and compare these with ALF mimics such as malaria, dengue fever and other tropical infectious diseases. METHODS: The study population included patients who presented with ALF and ALF mimics in a tertiary care center over two years. We retrospectively analyzed the patient case files and a comparison was made concerning the baseline demographic details, clinical profile, laboratory values and outcomes. RESULTS: Sixty-three patients were assessed, with 32 in ALF and 31 in ALF mimics group. The most common cause for ALF was hepatitis A virus (25%), followed by hepatitis B virus (18.7%), drug-induced liver injury (12.7%), autoimmune hepatitis (12.5%), hepatitis E virus (9.3%) and Wilson's disease (6.25%). In the ALF mimics group, malaria (58.06%) was the most common cause, followed by dengue fever (16.1%), leptospirosis (12.9%) and scrub typhus (12.9%). Patients in the ALF mimics group had significantly higher incidence of fever (p = 0.001), hepatosplenomegaly (p = 0.01), anemia (p = 0.02) and shorter jaundice to encephalopathy duration (p = 0.032) as compared to the ALF group, while higher transaminase levels (p = 0.03), bilirubin (p = 0.01), prothrombin time (p = 0.01), serum ammonia (p = 0.02) and mortality (p = 0.02) were observed in ALF patients. CONCLUSIONS: The most common cause for ALF was hepatitis A virus, followed by hepatitis B virus, while in ALF mimics it was malaria followed by dengue fever, in our study. Patients of ALF mimics can have similar presentation, but a high index of suspicion and awareness is required to identify the common infectious ALF mimics for early diagnosis.

A case of severe Plasmodium ovale malaria with acute respiratory distress syndrome and splenic infarction in a male traveller presenting in Italy.

BACKGROUND: Plasmodium ovale malaria is usually considered a tropical infectious disease associated with low morbidity and mortality. However, severe disease and death have previously been reported. CASE PRESENTATION: A case of severe P. ovale malaria in a healthy Caucasian man with a triangle splenic infarction and clinical progression towards Acute Respiratory Distress Syndrome was reported despite a rapid response to oral chloroquine treatment with 24-h parasitaemia clearance. CONCLUSION: Plasmodium ovale malaria is generally considered as a benign disease, with low parasitaemia. However, severe disease and death have occasionally been reported. It is important to be aware that occasionally it can progress to serious illness and death even in immunocompetent individuals.

Uncovering HIV and malaria interactions: the latest evidence and knowledge gaps.

The geographical distribution of malaria and HIV infections widely overlap in sub-Saharan Africa, constituting a complex global health challenge. The interplay between both infections raises concerns about potential immunological, clinical, and therapeutic interactions. Both diseases have been reported to exacerbate the transmission of the other, including the possible vertical transmission of HIV in pregnant individuals with malaria. Co-infection also increases the risk of adverse outcomes such as severe malaria and death. In addition, interactions between antiretroviral and antimalarial drugs have been reported, potentially reducing the efficacy of these drugs. We review the current knowledge of the epidemiological, clinical, immunological, and therapeutic interactions of both infections. We focus on the latest available data and identify key knowledge gaps that should be addressed to guide policy makers in providing optimal HIV and malaria prevention, care, and treatment in vulnerable populations.

Status of selected biochemical and coagulation profiles and platelet count in malaria and malaria-Schistosoma mansoni co-infection among patients attending at Dembiya selected Health Institutions, Northwest Ethiopia.

Malaria and schistosomiasis are infectious diseases that cause coagulation disorders, biochemical abnormalities, and thrombocytopenia. Malaria and Schistosoma mansoni co-infection cause exacerbations of health consequences and co-morbidities.This study aimed to compare the effect of malaria and Schistosoma mansoni co-infection and malaria infection on selected biochemical and coagulation profiles, and platelet count. An institutional-based comparative cross-sectional study was conducted from March 30 to August 10, 2022. A total of 70 individuals were enrolled in the study using a convenient sampling technique. Wet mount and Kato Katz techniques were conducted to detect Schistosoma mansoni in a stool sample. Blood films were prepared for the detection of plasmodium. The data was coded and entered into EpiData version 3.1 before being analyzed with SPSS version 25. An independent t test was used during data analysis. A P-value of less than 0.05 was considered statistically significant. The mean [SD] of alanine aminotransferase, aspartate aminotransferase, creatinine, total bilirubin, and direct bilirubin in the co-infected was higher than in malaria infected participants. However, the mean of total protein and glucose in co-infected was lower than in the malaria infected participants. The mean of prothrombin time, international normalization ratio, and activated partial thromboplastin time in co-infected was significantly higher, while the platelet count was lower compared to malaria infected participants. Biochemical and coagulation profiles, and platelet count status in co-infection were changed compared to malaria infected participants. Therefore, biochemical and coagulation profiles and platelet count tests should be used to monitor and manage co-infection related complications and to reduce co-infection associated morbidity and mortality.

Navigating the terrain of neutrophil extracellular traps in severe malaria pathogenesis.

Du, Ren, et al. recently showed in a Plasmodium berghei ANKA (PbA) experimental malaria model that phosphatase of regenerating liver 2 (PRL2) regulates neutrophil extracellular traps (NETs) in severe malaria (SM)-related acute lung injury (ALI). PRL2 deficiency caused SM with ALI in a mouse model by increasing NETs in pulmonary tissue; hydroxychloroquine (HCQ) may ameliorate this.

Assessment of Culicidae collection methods for xenomonitoring lymphatic filariasis in malaria co-infection context in Burkina Faso.

BACKGROUND: Entomological surveillance of lymphatic filariasis and malaria infections play an important role in the decision-making of national programs to control, or eliminate these both diseases. In areas where both diseases prevalence is low, a large number of mosquitoes need to be sampled to determine vectors infection rate. To do this, efficient mosquito collection methods must be used. This study is part in this framework, to assess appropriate mosquito collection methods for lymphatic filariasis xenomonitoring in a coexistence context with malaria in Burkina Faso. METHODOLOGY/PRINCIPAL FINDINGS: Mosquito collections were performed between August and September 2018 in four villages (Koulpissi, Seiga, and Péribgan, Saptan), distributed in East and South-West health regions of Burkina Faso. Different collection methods were used: Human Landing Catches (HLC) executed indoor and outdoor, Window Exit-Trap, Double Net Trap (DNT) and Pyrethrum Spray Catches (PSC). Molecular analyses were performed to identify Anopheles gambiae s.l. sibling species and to detect Wuchereria bancrofti and Plasmodium falciparum infection in Anopheles mosquitoes. A total of 3 322 mosquitoes were collected among this, Anopheles gambiae s.l. was the vector caught in largest proportion (63.82%). An. gambiae s.l. sibling species molecular characterization showed that An. gambiae was the dominant specie in all villages. The Human Landing Catches (indoor and outdoor) collected the highest proportion of mosquitoes (between 61.5% and 82.79%). For the sampling vectors infected to W. bancrofti or P. falciparum, PSC, HLC and Window Exit-Trap were found the most effective collection methods. CONCLUSIONS/SIGNIFICANCE: This study revealed that HLC indoor and outdoor remained the most effective collection method. Likewise, the results showed the probability to use Window Exit-Trap and PSC collection methods to sample Anopheles infected.

Prevalence and determinants of anaemia among pregnant women in a high malaria transmission setting: a cross-sectional study in rural Burkina Faso.

Introduction: anemia, the commonest nutritional deficiency disorder among pregnant women in sub-Saharan Africa, is associated with severe peripartum complications. Its regular monitoring is necessary to timely inform clinical and preventive decision-making. The aim of this study was to assess the prevalence and determinants of anemia among pregnant women in rural areas of Burkina Faso. Methods: between August 2019 and March 2020, a cross-sectional study was conducted to collect maternal sociodemographic, gynaeco-obstetric, and medical characteristics by face-to-face interview or by review of antenatal care books. In addition, maternal malaria was diagnosed by standard microscopy and the hemoglobin levels (Hb) measured by spectrophotometry. The proportion of anaemia (Hb<11.0 g/dL), moderate (7.0

Methemoglobin levels in malaria: a systematic review and meta-analysis of its association with Plasmodium falciparum and Plasmodium vivax infections and disease severity.

Reports indicate that Plasmodium infections influence methemoglobin levels. However, findings have been inconclusive or have varied across different geographic and demographic contexts. This systematic review and meta-analysis aimed to consolidate existing data regarding the association between Plasmodium infections and alterations in methemoglobin levels related to the severity of the infection. A comprehensive literature search of several databases, including Ovid, ProQuest, Embase, Scopus, MEDLINE, and PubMed, was conducted to identify relevant studies that examined methemoglobin levels in patients with malaria. Qualitative synthesis and meta-analysis of the pooled standardized mean difference were conducted to synthesize the differences in methemoglobin levels between: (1) patients with malaria and those without malaria and (2) patients with severe malaria and those with uncomplicated malaria based on various themes including publication year, study design, study area, Plasmodium species, age group, symptomatic status, severity status, and method of malaria detection. Of the 1846 studies that were initially identified from the main databases and additional searches on Google Scholar, 10 studies met the eligibility criteria and were selected for this review. The systematic review distinctly highlighted an association between malaria and elevated methemoglobin levels, an observation consistent across diverse geographical regions and various Plasmodium species. Furthermore, the meta-analysis confirmed this by demonstrating increased methemoglobin levels in patients with malaria compared to those without malaria (P < 0.001, Hedges' g 2.32, 95% CI 1.36-3.29, I2 97.27, 8 studies). Moreover, the meta-analysis found elevated methemoglobin levels in patients with severe malaria compared to those with uncomplicated malaria (P < 0.001, Hedges' g 2.20, 95% CI 0.82-3.58, I2 96.20, 5 studies). This systematic review and meta-analysis revealed increased methemoglobin levels in patients with P. falciparum and P. vivax infections, with a notable association between elevated methemoglobin levels and severe malaria. Future research should focus on elucidating the specific mechanisms by which changes in methemoglobin levels are related to infections by P. falciparum and P. vivax, particularly in terms of severity, and how these alterations could potentially impact patient management and treatment outcomes.

Scoring systems for prediction of malaria and dengue fever in non-endemic areas among travellers arriving from tropical and subtropical areas.

BACKGROUND: Fever is a common symptom among travellers returning from tropical/subtropical areas to Europe, and promptly distinguishing severe illnesses from self-limiting febrile syndromes is important but can be challenging due to non-specific clinical presentation. METHODS: A cross-sectional study enrolled adults and children who sought care during 2015-2020 at Karolinska University Hospital, Stockholm, Sweden with fever within 2 months after returning from travel to a tropical/subtropical area. Data on symptoms and laboratory parameters were prospectively and retrospectively collected. Two separate scoring systems for malaria and dengue were developed based on backward elimination regressions. RESULTS: In total, 2113 adults (18-94 years) and 202 children (1-17 years) were included, with 112 (4.8%) confirmed malaria by blood thick smear and 90 (3.9%) PCR/serology dengue-positive cases. Malaria was more likely in a patient who had visited sub-Saharan Africa and presented with combination of thrombocytopenia, anaemia and fever ≥39.5°C. Leucopenia, muscle pain and rash after travelling to Asia or South/Latin America indicated high probability of dengue. Two scoring systems with points between 0 and 7 for prediction of malaria or dengue were created based on the above predictors. Scores ≥3 indicated >80% sensitivity and specificity for malaria and >90% specificity for dengue in children and adults (area under the curve (AUC) for dengue: 0.92 in adults (95% CI 0.90 to 0.95) and 0.95 in children (95% CI 0.88 to 1.0); AUC for malaria: 0.93 in adults (95% CI 0.91 to 0.96) and 0.88 in children (95% CI 0.78 to 0.99)). Internal validation of optimism and overfitting was managed with bootstrap. CONCLUSION: The presented scoring systems provide novel tools for structured assessment of patients with tropical fever in a non-endemic area and highlight clinical signs associated with a potential severe aetiology to direct the need for microbial investigation.

Clinical description of dengue and chikungunya virus infections amongst acute febrile patients in a malaria endemic area of Mfou, the Centre region of Cameroon.

This study aims to determine the frequency and clinical manifestations of dengue and chikungunya viral infections in the district hospital of Mfou, Centre region of Cameroon where malaria is endemic. Blood samples were collected from suspected cases and tested for Plasmodium parasites and for the molecular detection of viral RNAs (dengue, zika and chikungunya viruses) using TRIOPLEX qPCR. A total of 108 patients were clinically suspected among which 25 % were male and 50 % were less than 15.5 years old. Of these 14.8 % (16/108) and 2.8 % (3/108) had acute dengue and chikungunya fevers respectively. Co-infection with malaria was reported in 56.3 % (9/16) of Dengue cases and 33.3 % (1/3) of chikungunya cases. Clinical profiling further revealed that nausea and vomiting show a significant difference in dengue infected individuals to those of non-infected individuals (P = 0.027). The presence of dengue fever and chikungunya fever and the absence of specific clinical manifestations highlight the need to strengthen surveillance of acute febrile infections for a better estimation of the burden of arboviruses.