-
Malaria Journal Jan 2024Malaria remains a major public health problem in the Republic of Congo, with Plasmodium falciparum being the deadliest species of Plasmodium in humans. Vector...
BACKGROUND
Malaria remains a major public health problem in the Republic of Congo, with Plasmodium falciparum being the deadliest species of Plasmodium in humans. Vector transmission of malaria is poorly studied in the country and no previous report compared rural and urban data. This study aimed to determine the Anopheles fauna and the entomological indices of malaria transmission in the rural and urban areas in the south of Brazzaville, and beyond.
METHODS
Indoor household mosquitoes capture using electric aspirator was performed in rural and urban areas during raining and dry seasons in 2021. The identification of Anopheles species was done using binocular magnifier and nested-PCR. TaqMan and nested-PCR were used to detect the Plasmodium species in the head/thorax and abdomens of Anopheles. Some entomological indices including the sporozoite infection rate, the entomological inoculation rate and the man biting rate were estimated.
RESULTS
A total of 699 Anopheles mosquitoes were collected: Anopheles gambiae sensu lato (s.l.) (90.7%), Anopheles funestus s.l. (6.9%), and Anopheles moucheti (2.4%). Three species of An. gambiae s.l. were identified including Anopheles gambiae sensu stricto (78.9%), Anopheles coluzzii (15.4%) and Anopheles arabiensis (5.7%). The overall sporozoite infection rate was 22.3% with a predominance of Plasmodium falciparum, followed by Plasmodium malariae and Plasmodium ovale. Anopheles aggressiveness rate was higher in households from rural area (1.1 bites/night) compared to that from urban area (0.8 ib/p/n). The overall entomological inoculation rate was 0.13 ib/p/n. This index was 0.17 ib/p/n and 0.092 ib/p/n in rural and in urban area, respectively, and was similar during the dry (0.18 ib/p/n) and rainy (0.14 ib/p/n) seasons.
CONCLUSION
These findings highlight that malaria transmission remains high in rural and urban area in the south of Republic of Congo despite the ongoing control efforts, thereby indicating the need for more robust interventions.
Topics: Animals; Humans; Malaria, Falciparum; Congo; Mosquito Vectors; Plasmodium; Plasmodium falciparum; Malaria; Bites and Stings; Sporozoites; Anopheles
PubMed: 38229020
DOI: 10.1186/s12936-023-04823-9 -
Malaria Journal Jan 2024Malaria remains a major public health problem in sub-Saharan Africa, particularly in Benin. The present study aims to evaluate the different Plasmodium species...
BACKGROUND
Malaria remains a major public health problem in sub-Saharan Africa, particularly in Benin. The present study aims to evaluate the different Plasmodium species transmitted by malaria vectors in the communes of Cove, Zagnanado and Ouinhi, Southern Benin.
METHODS
The study was conducted between December 2021 and October 2022 in 60 villages spread over the three study communes. Adult mosquitoes were collected from four houses in each village using human landing catches (HLCs). After morphological identification, a subsample of Anopheles gambiae, Anopheles funestus and Anopheles nili was analysed by PCR to test for their infection to the different Plasmodium species.
RESULTS
Anopheles gambiae was collected at higher frequency in all the three study communes, representing 93.5% (95% CI 92.9-94) of all collected mosquitoes (n = 10,465). In total, five molecular species were found, An. gambiae sensu stricto (s.s.) and Anopheles coluzzii of the Gambiae complex, An. funestus and Anopheles leesoni of the Funestus group, and An. nili s.s., the sole species of the Nili group. From the five molecular species, four (An. gambiae s.s., An. coluzzii, An. funestus s.s. and An. nili s.s.) were found to be infected. Plasmodium falciparum was the main Plasmodium species in the study area, followed by Plasmodium vivax and Plasmodium ovale. Only An. gambiae s.s. was infected with all three Plasmodium species, while An. coluzzii was infected with two species, P. falciparum and P. vivax.
CONCLUSIONS
Plasmodium falciparum was the only species tested for in malaria vectors in Benin, and remains the only one against which most control tools are directed. It is, therefore, necessary that particular attention be paid to secondary Plasmodium species for an efficient control of the disease. The presence of P. vivax emphasizes the need for an update of case management for malaria.
Topics: Animals; Adult; Humans; Anopheles; Malaria; Benin; Plasmodium vivax; Mosquito Vectors; Africa, Western; Malaria, Falciparum; Plasmodium falciparum; Plasmodium; Malaria, Vivax
PubMed: 38225627
DOI: 10.1186/s12936-023-04834-6 -
Acta Parasitologica Mar 2024Microscopic diagnosis of Giemsa-stained thick and thin blood films remained the gold standard laboratory method for the diagnosis of malaria. In this context, we felt it...
PURPOSE
Microscopic diagnosis of Giemsa-stained thick and thin blood films remained the gold standard laboratory method for the diagnosis of malaria. In this context, we felt it was important to conduct this evaluation with 40 public medical biology laboratories (MBLs) in the Abidjan 1 health region that perform blood parasitology tests to improve their implementation process.
METHODS
This descriptive and analytical study took place in July 2020 and involved participating laboratories (PLs) from the public sector in Abidjan. A set of 3 blood smear slides of variable parasite densities (PDs) with assigned values (AVs) of parasite densities and assigned Plasmodium species was used. The criterion for establishing the parasite density compliance interval was assigned values of ± 25%, and the performance rates were compared to the 80% recommended by the WHO for the African region.
RESULTS
Nearly a quarter (11/40) of the participating laboratories had a compliance rate greater than 80%, including 10 with a performance of 100% for the ability to identify parasites. Regarding identifying plasmodial species, a concordance rate of 100% was obtained for slide 1 for Plasmodium falciparum, while this rate was 20% for slide 2 for Plasmodium ovale. For parasite densities < 200/µl, 87.5% of the participating laboratories (PLs) had a performance rate lower than 80%, while 95% of these PLs had a performance rate higher than 80% for parasitaemia > 2000/µl.
CONCLUSIONS
There is a need to strengthen adapted to low parasitaemia, to improve the biological confirmation of malaria in Côte d'Ivoire.
Topics: Cote d'Ivoire; Microscopy; Humans; Malaria; Health Facilities; Laboratories; Plasmodium falciparum; Public Health; Plasmodium ovale; Plasmodium
PubMed: 38225530
DOI: 10.1007/s11686-023-00754-2 -
Acta Tropica Mar 2024Combining the advantages of PCR and LAMP, we described a new technique, namely PCR-LAMP, for malaria diagnosis. The whole process of DNA amplification can be completed...
Combining the advantages of PCR and LAMP, we described a new technique, namely PCR-LAMP, for malaria diagnosis. The whole process of DNA amplification can be completed in 35 min. This hybrid amplification technique markedly improved the sensitivity of detection compared to the classic single PCR or LAMP assay alone. PCR-LAMP assay had a detection limit of 1 copy/µL for P. knowlesi and P. ovale, 0.1 copy/µL for P. vivax, P. falciparum and P. malariae, respectively. To facilitate the endpoint detection, xylenol orange was added. Positive samples were indicated in orange while negative reactions were violet. The inclusion of xylenol orange into the LAMP reaction mix significantly reduces the post-amplification workload. Without relying on the use of specific instruments, the color changes of the amplicons could be visualized directly through the naked eye. In conclusion, PCR-LAMP poses the potential to be developed as a new malaria molecular diagnosis tool.
Topics: Humans; Sensitivity and Specificity; Plasmodium; Malaria; Nucleic Acid Amplification Techniques; Malaria, Falciparum; Malaria, Vivax; Polymerase Chain Reaction; Plasmodium falciparum; Plasmodium vivax; Phenols; Sulfoxides; Molecular Diagnostic Techniques
PubMed: 38199452
DOI: 10.1016/j.actatropica.2024.107120 -
EClinicalMedicine Jan 2024Despite significant progress in malaria control over the past twenty years, malaria remains a leading cause of child morbidity and mortality in Tropical Africa. As most...
BACKGROUND
Despite significant progress in malaria control over the past twenty years, malaria remains a leading cause of child morbidity and mortality in Tropical Africa. As most patients do not consult any health facility much uncertainty persists about the true burden of the disease and the range of individual differences in susceptibility to malaria.
METHODS
Over a 25-years period, from 1990 to 2015, the inhabitants of Dielmo village, Senegal, an area of intense malaria transmission, have been monitored daily for their presence in the village and the occurrence of diseases. In case of fever thick blood films were systematically examined through microscopy for malaria parasites and patients received prompt diagnosis and treatment.
FINDINGS
We analysed data collected in 111 children and young adults monitored for at least 10 years (mean 17.3 years, maximum 25 years) enrolled either at birth (95 persons) or during the two first years of life. A total of 11,599 episodes of fever were documented, including 5268 malaria attacks. The maximum number of malaria attacks in a single person was 112. Three other persons suffered one hundred or more malaria attacks during follow-up. The minimum number of malaria attacks in a single person was 11. The mean numbers of malaria attacks in children reaching their 4th, 7th, and 10th birthdays were 23.0, 37.7, and 43.6 attacks since birth, respectively. Sixteen children (14.4%) suffered ten or more malaria attacks each year at ages 1-3 years, and six children (5.4%) each year at age 4-6 years.
INTERPRETATION
Long-term close monitoring shows that in highly endemic areas the malaria burden is higher than expected. Susceptibility to the disease may vary up to 10-fold, and for most children childhood is an endless history of malaria fever episodes. No other parasitic, bacterial or viral infection in human populations has such an impact on health.
FUNDING
The Pasteur Institutes of Dakar and Paris, the Institut de Recherche pour le Développement, and the French Ministry of Cooperation provided funding.
PubMed: 38188691
DOI: 10.1016/j.eclinm.2023.102379 -
Journal of Vector Borne Diseases 2023Severe malaria is a medical emergency and can lead to severe complications and death if not treated promptly and appropriately. Along with Plasmodium falciparum, P....
BACKGROUND & OBJECTIVES
Severe malaria is a medical emergency and can lead to severe complications and death if not treated promptly and appropriately. Along with Plasmodium falciparum, P. knowlesi is increasingly recognised as a significant cause of fatal and severe malaria.
METHODS
We performed a retrospective review on 54 cases of severe malaria in a district hospital in Kapit, Sarawak, from January 2018 to May 2019. The patients' demographics, clinical features, complications based on organ involvement, and treatment outcomes were examined.
RESULTS
There were 54 cases of severe malaria, with the majority being male (70%) and between the ages of 40 and 49 (26%). All patients with severe malaria were febrile or had a history of pyrexia except for one patient. P. knowlesi (81.5%) was the most common species causing severe malaria in our study, followed by P. falciparum (13%), and P. vivax (5.5%). There were no cases of severe malaria caused by P. ovale or P. malariae. Hyperparasitaemia was present in 76% of patients and the median parasitemia value at hospital admission was 33,944 parasites/μL (interquartile range: 19,920-113,285 parasites/μL). Circulatory shock was observed in 17 patients (31.5%). There were eight patients with acute renal failure and six patients with respiratory distress. One patient died as a result of severe malaria with multiorgan involvement (1.9% fatality rate).
INTERPRETATION & CONCLUSION
P. knowlesi is the most common cause of severe malaria in Kapit, Sarawak, Malaysia. Recognizing symptoms of severe malaria and prompt administration of antimalarial are critical for good clinical outcomes.
Topics: Humans; Male; Adult; Middle Aged; Female; Malaysia; Borneo; Plasmodium knowlesi; Malaria; Antimalarials; Malaria, Vivax; Malaria, Falciparum
PubMed: 38174522
DOI: 10.4103/0972-9062.374238 -
Microbiology Spectrum Feb 2024Malaria remains a global health problem, with 247 million cases and 619,000 deaths in 2021. Diagnosis of species is important for administering the appropriate...
Automatic patient-level recognition of four species on thin blood smear by a real-time detection transformer (RT-DETR) object detection algorithm: a proof-of-concept and evaluation.
Malaria remains a global health problem, with 247 million cases and 619,000 deaths in 2021. Diagnosis of species is important for administering the appropriate treatment. The gold-standard diagnosis for accurate species identification remains the thin blood smear. Nevertheless, this method is time-consuming and requires highly skilled and trained microscopists. To overcome these issues, new diagnostic tools based on deep learning are emerging. This study aimed to evaluate the performances of a real-time detection transformer (RT-DETR) object detection algorithm to discriminate species on thin blood smear images. The algorithm was trained and validated on a data set consisting in 24,720 images from 475 thin blood smears corresponding to 2,002,597 labels. Performances were calculated with a test data set of 4,508 images from 170 smears corresponding to 358,825 labels coming from six French university hospitals. At the patient level, the RT-DETR algorithm exhibited an overall accuracy of 79.4% (135/170) with a recall of 74% (40/54) and 81.9% (95/116) for negative and positive smears, respectively. Among positive smears, the global accuracy was 82.7% (91/110) with a recall of 90% (38/42), 81.8% (18/22), and 76.1% (35/46) for , and respectively. The RT-DETR model achieved a World Health Organization (WHO) competence level 2 for species identification. Besides, the RT-DETR algorithm may be run in real-time on low-cost devices such as a smartphone and could be suitable for deployment in low-resource setting areas lacking microscopy experts.IMPORTANCEMalaria remains a global health problem, with 247 million cases and 619,000 deaths in 2021. Diagnosis of species is important for administering the appropriate treatment. The gold-standard diagnosis for accurate species identification remains the thin blood smear. Nevertheless, this method is time-consuming and requires highly skilled and trained microscopists. To overcome these issues, new diagnostic tools based on deep learning are emerging. This study aimed to evaluate the performances of a real-time detection transformer (RT-DETR) object detection algorithm to discriminate species on thin blood smear images. Performances were calculated with a test data set of 4,508 images from 170 smears coming from six French university hospitals. The RT-DETR model achieved a World Health Organization (WHO) competence level 2 for species identification. Besides, the RT-DETR algorithm may be run in real-time on low-cost devices and could be suitable for deployment in low-resource setting areas.
Topics: Humans; Plasmodium; Malaria; Malaria, Falciparum; Algorithms; Plasmodium falciparum; Piperazines
PubMed: 38171008
DOI: 10.1128/spectrum.01440-23 -
Trends in Parasitology Mar 2024
Topics: Plasmodium ovale
PubMed: 38160179
DOI: 10.1016/j.pt.2023.12.010 -
Frontiers in Medicine 2023The lack of well-preserved material upon which to base the paleo-microbiological detection of parasites has prevented extensive documentation of past outbreaks of...
INTRODUCTION
The lack of well-preserved material upon which to base the paleo-microbiological detection of parasites has prevented extensive documentation of past outbreaks of malaria in Europe. By trapping intact erythrocytes at the time of death, dental pulp has been shown to be a suitable tissue for documenting ancient intraerythrocytic pathogens such as parasites.
METHODS
Total DNA and proteins extracted from 23 dental pulp specimens collected from individuals exhumed from the 9th to 13th century archaeological site in Mariana, Corsica, were analyzed using open-mind paleo-auto-immunohistochemistry and direct metagenomics, -targeting immunochromatography assays. All experiments incorporated appropriate negative controls.
RESULTS
Paleo-auto-immunohistochemistry revealed the presence of parasites spp. in the dental pulp of nine teeth. A further immunochromatography assay identified the presence of at least one antigen in nine individuals. The nine teeth, for which the PfHRP-2 antigen specific of was detected, were also positive using paleo-autoimmunohistochemistry and metagenomics.
CONCLUSION
Dental pulp erythrocytes proved to be suitable for the direct paleomicrobiology documentation of malaria in nine individuals buried in medieval Corsica, in agreement with historical data. This provides additional information on the millennial dynamics of spp. in the Mediterranean basin.
PubMed: 38143446
DOI: 10.3389/fmed.2023.1265964 -
Frontiers in Cellular and Infection... 2023The zoonotic malaria parasite is an important public health concern in Southeast Asia. Invasion of host erythrocytes is essential for parasite growth, and thus,...
The zoonotic malaria parasite is an important public health concern in Southeast Asia. Invasion of host erythrocytes is essential for parasite growth, and thus, understanding the repertoire of parasite proteins that enable this process is vital for identifying vaccine candidates and how some species are able to cause zoonotic infection. Merozoite surface protein 1 (MSP1) is found in all malaria parasite species and is perhaps the most well-studied as a potential vaccine candidate. While MSP1 is encoded by a single gene in , all other human infective species (, , , and ) additionally encode a divergent paralogue known as MSP1P, and little is known about its role or potential functional redundancy with MSP1. We, therefore, studied the function of merozoite surface protein 1 paralog (PkMSP1P), using both recombinant protein and CRISPR-Cas9 genome editing. The recombinant 19-kDa C-terminus of PkMSP1P (PkMSP1P-19) was shown to bind specifically to human reticulocytes. However, immunoblotting data suggested that PkMSP1P-19-induced antibodies can recognize PkMSP1-19 and vice versa, confounding our ability to separate the properties of these two proteins. Targeted disruption of the gene profoundly impacts parasite growth, demonstrating for the first time that PkMSP1P is important in growth of and likely plays a distinct role from PkMSP1. Importantly, the MSP1P KO also enabled functional characterization of the PkMSP1P-19 antibodies, revealing clear immune cross-reactivity between the two paralogues, highlighting the vital importance of genetic studies in contextualizing recombinant protein studies.
Topics: Humans; Merozoite Surface Protein 1; Plasmodium knowlesi; Malaria; Erythrocytes; Malaria, Vivax; Antibodies; Malaria, Falciparum; Recombinant Proteins; Vaccines
PubMed: 38111629
DOI: 10.3389/fcimb.2023.1314533