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PloS One 2024Mansonella spp. have been reported to have a wide global distribution. Despite the distribution and co-occurrence with other filarial parasites like Wuchereria...
Mansonella spp. have been reported to have a wide global distribution. Despite the distribution and co-occurrence with other filarial parasites like Wuchereria bancrofti, Onchocerca volvulus and Loa loa, it is given little attention. There are few surveillance programmes for assessing the distribution of mansonellosis, due to the associated mild to no symptoms experienced by infected people. However, addressing this infection is critical to the onchocerciasis control program as current rapid diagnostic tools targeting O. volvulus have the tendency to cross react with Mansonella species. In this study we identified and characterised M. perstans from five sites in two districts in the Volta Region of Ghana and compared them to samples from other regions. Night blood smears and filter blood blots were obtained from individuals as part of a study on lymphatic filariasis. The Giemsa-stained smears were screened by microscopy for the presence of filarial parasites. Genomic DNA was extracted from blood blots from 39 individuals that were positive for M. perstans and Nested PCR targeting the internal spacer 1 (ITS-1) was conducted. Of these, 30 were sequenced and 24 sequences were kept for further analysis. Phylogenetic analysis of 194 nucleotide positions showed no differences in the samples collected. The similarities suggests that there could be one species in this area. However, more robust studies with larger sample sizes are required to draw such conclusions. We also observed a clustering of the samples from Ghana with reference sequences from Africa and Brazil, suggesting they could be related. This study draws further attention to a neglected infection, presents the first characterisation of M. perstans in Ghana and calls for more population-based studies across different geographical zones to ascertain species variations and disease distribution.
Topics: Ghana; Mansonella; Humans; Mansonelliasis; Animals; Phylogeny; Male; Female
PubMed: 38848396
DOI: 10.1371/journal.pone.0295089 -
Frontiers in Tropical Diseases Apr 2024Mouse models of human filarial infections are not only urgently needed to investigate the biology of the nematodes and their modulation of the host's immunity, but will...
INTRODUCTION
Mouse models of human filarial infections are not only urgently needed to investigate the biology of the nematodes and their modulation of the host's immunity, but will also provide a platform to screen and test novel anti-filarial drugs. Recently, murine infection models have been stablished using immunocompromised mouse strains, whereas murine infections have not been implemented until now.
METHODS
Therefore, we aim to establish experimental infections using the immunocompromised mouse strains RAG2IL-2Rγ (lack B, T and natural killer cells), IL-4Rα/IL-5 (impaired IL-4/5 signalling and eosinophil activation) and NOD.Cg-PrkdcIl2rg l/SzJ (NOD scid gamma, NSG) BALB/c mice (lack mature lymphocytes) through subcutaneous (s.c.) or intraperitoneal (i.p.) inoculation of infective stage 3 larvae (L3) isolated from engorged vectors.
RESULTS
In total, 145 immunocompromised mice have been inoculated with 3,250 , 3,337 , and 2,720 L3 to comparatively analyse which immunocompromised mouse strain is susceptible to human filarial infections. Whereas, no and L3 could be recovered upon 2-63 days post-inoculation, a 62-66% L3 recovery rate could be achieved in the different mouse strains. Gender of mice, type of inoculation (s.c. or i.p.) or time point of analysis (2-63 days post inoculation) did not interfere with the success of L3 recovery. In addition, administration of the immune suppressants hydrocortisone, prednisolone and cyclophosphamide did not restore L3 recovery rates.
DISCUSSION
These findings show that RAG2IL-2RgBALB/c and C57BL/6, IL-4Rα/IL-5 BALB/c and NSG mice were not susceptible to and L3 inoculation using the applied methods, whereas infection could be maintained. Further studies should investigate if humanized immunocompromised mice might be susceptible to . and .
PubMed: 38655273
DOI: 10.3389/fitd.2024.1293632 -
PLoS Neglected Tropical Diseases Apr 2024Filariasis, a neglected tropical disease caused by roundworms, is a significant public health concern in many tropical countries. Microscopic examination of blood...
Filariasis, a neglected tropical disease caused by roundworms, is a significant public health concern in many tropical countries. Microscopic examination of blood samples can detect and differentiate parasite species, but it is time consuming and requires expert microscopists, a resource that is not always available. In this context, artificial intelligence (AI) can assist in the diagnosis of this disease by automatically detecting and differentiating microfilariae. In line with the target product profile for lymphatic filariasis as defined by the World Health Organization, we developed an edge AI system running on a smartphone whose camera is aligned with the ocular of an optical microscope that detects and differentiates filarias species in real time without the internet connection. Our object detection algorithm that uses the Single-Shot Detection (SSD) MobileNet V2 detection model was developed with 115 cases, 85 cases with 1903 fields of view and 3342 labels for model training, and 30 cases with 484 fields of view and 873 labels for model validation before clinical validation, is able to detect microfilariae at 10x magnification and distinguishes four species of them at 40x magnification: Loa loa, Mansonella perstans, Wuchereria bancrofti, and Brugia malayi. We validated our augmented microscopy system in the clinical environment by replicating the diagnostic workflow encompassed examinations at 10x and 40x with the assistance of the AI models analyzing 18 samples with the AI running on a middle range smartphone. It achieved an overall precision of 94.14%, recall of 91.90% and F1 score of 93.01% for the screening algorithm and 95.46%, 97.81% and 96.62% for the species differentiation algorithm respectively. This innovative solution has the potential to support filariasis diagnosis and monitoring, particularly in resource-limited settings where access to expert technicians and laboratory equipment is scarce.
Topics: Artificial Intelligence; Microscopy; Humans; Animals; Filariasis; Microfilariae; Algorithms; Smartphone; Elephantiasis, Filarial
PubMed: 38630833
DOI: 10.1371/journal.pntd.0012117 -
Parasites & Vectors Mar 2024Culicoides, also known as biting midges, carry pathogens which include Mansonella perstans. Mansonella perstans is a nematode parasite implicated in a number of disease...
BACKGROUND
Culicoides, also known as biting midges, carry pathogens which include Mansonella perstans. Mansonella perstans is a nematode parasite implicated in a number of disease outcomes. Even though a high prevalence of about 75% M. perstans infection has been recorded in some communities in the middle belt of Ghana, and a wide diversity of Culicoides species has been identified, the exact Culicoides species transmitting M. perstans in Ghana has not yet been deciphered. This study therefore aimed at assessing the species diversity of Culicoides and their role in the transmission of M. perstans in the middle belt of Ghana.
METHODS
Culicoides species were sampled from 11 communities in the Asante-Akim North and Sene West districts in the middle belt of Ghana. Centre for Disease Control (CDC) UV light traps, as well as human bait (i.e. human landing catch and engorged catch) methods were used to assess the species abundance and diversity of Culicoides in the study communities in the wet and dry season. A colorimetric Loop-Mediated Isothermal Amplification (LAMP) assay was performed to assess the vector competence of the various Culicoides species.
RESULTS
A total of 4810 Culicoides from 6 species were sampled. These included Culicoides inornatipennis, C. milnei, C. schultzei, C. grahamii, C. neavei, and C. imicola. Culicoides imicola was the most abundant species (56%) followed by C. grahamii (16%). Light traps sampled the most diverse species (6 species). Human landing catch and engorged catch methods identified three anthropophilic species, C. grahamii, C. milnei, and C. inornatipennis, with C. grahamii being the most anthropophilic with a peak biting time between the hours of 5 p.m. to 6 p.m. Generally, there was relatively higher species abundance in the wet than dry season. LAMP assay identified C. grahamii as the potential vector for M. perstans transmission in the middle belt of Ghana.
CONCLUSIONS
For the first time, we have demonstrated that C. grahamii is the potential competent vector for M. perstans transmission in the middle belt of Ghana. It is more abundant in the rainy season and has a peak biting time between the hours of 5 and 6 p.m.
Topics: Humans; Animals; Mansonella; Ceratopogonidae; Ghana; Insect Vectors; Prevalence
PubMed: 38475862
DOI: 10.1186/s13071-024-06179-8 -
Pathogens (Basel, Switzerland) Feb 2024Biting midges belonging to the genus are tiny stout-shaped hematophagous insects and are thought to transmit the filarial nematode . Little is known about the fauna in...
Biting midges belonging to the genus are tiny stout-shaped hematophagous insects and are thought to transmit the filarial nematode . Little is known about the fauna in the rain forest belt of the Littoral Region of Cameroon. This study was designed to investigate the diversity, abundance and distribution of spp. and their role as the purported vector(s) of . Overnight light trap collections and human landing catches (HLCs) revealed eight species of with being the most abundant species followed by . Four anthropophilic species (, , and ) were determined by the HLCs with a higher abundance in the 4-6 p.m. collections. The drop trap technique and Mp419 LAMP assay confirmed to be the most efficient vector in enabling the development of the microfilarial stage to the infective larval form of . The LAMP assay also revealed that natural transmission of this nematode is fostered by and in the wild. In conclusion, was shown to be the main vector of in the rain forest belt of the Littoral Region of Cameroon.
PubMed: 38392884
DOI: 10.3390/pathogens13020146 -
Parasites & Vectors Feb 2024Nematodes of the Ascarididae, Ancylostomatidae and Onchocercidae families are parasites of human and veterinary importance causing infections with high prevalence...
BACKGROUND
Nematodes of the Ascarididae, Ancylostomatidae and Onchocercidae families are parasites of human and veterinary importance causing infections with high prevalence worldwide. Molecular tools have significantly improved the diagnosis of these helminthiases, but the selection of genetic markers for PCR or metabarcoding purposes is often challenging because of the resolution these may show.
METHODS
Nuclear 18S rRNA, internal transcribed spacers 1 (ITS-1) and 2 (ITS-2), mitochondrial gene cytochrome oxidase 1 (cox1) and mitochondrial rRNA genes 12S and 16S loci were studied for 30 species of the mentioned families. Accordingly, their phylogenetic interspecies resolution, pairwise nucleotide p-distances and sequence availability in GenBank were analyzed.
RESULTS
The 18S rRNA showed the least interspecies resolution since separate species of the Ascaris, Mansonella, Toxocara or Ancylostoma genus were intermixed in phylogenetic trees as opposed to the ITS-1, ITS-2, cox1, 12S and 16S loci. Moreover, pairwise nucleotide p-distances were significantly different in the 18S compared to the other loci, with an average of 99.1 ± 0.1%, 99.8 ± 0.1% and 98.8 ± 0.9% for the Ascarididae, Ancylostomatidae and Onchocercidae families, respectively. However, ITS-1 and ITS-2 average pairwise nucleotide p-distances in the three families ranged from 72.7% to 87.3%, and the cox1, 12S and 16S ranged from 86.4% to 90.4%. Additionally, 2491 cox1 sequences were retrieved from the 30 analyzed species in GenBank, whereas 212, 1082, 994, 428 and 143 sequences could be obtained from the 18S, ITS-1, ITS-2, 12S and 16S markers, respectively.
CONCLUSIONS
The use of the cox1 gene is recommended because of the high interspecies resolution and the large number of sequences available in databases. Importantly, confirmation of the identity of an unknown specimen should always be complemented with the careful morphological examination of worms and the analysis of other markers used for specific parasitic groups.
Topics: Humans; Animals; RNA, Ribosomal, 18S; Sarcocystis; Sarcocystosis; Phylogeny; Nematoda; Nucleotides
PubMed: 38378676
DOI: 10.1186/s13071-023-06113-4 -
Current Research in Parasitology &... 2024Following the successful eradication of , there are now just three species of conventional microfilaremic human filarial parasites endemic to the Brazilian Amazon... (Review)
Review
Following the successful eradication of , there are now just three species of conventional microfilaremic human filarial parasites endemic to the Brazilian Amazon region: , and The zoonotic filarial parasite is also found in the Amazon region as are several sylvatic filarial parasites, some of which have been recorded causing zoonoses and some of which have never been recorded outside the region. is only found in the Amazonia onchocerciasis focus in the Brazilian state of Roraima where it affects the people of the Yanomami tribe living around the densely forested Venezuela border region. is by far the most common filarial parasite in Brazil and has a broad but patchy distribution throughout the western Amazon region. Recorded in the Brazilian states of Acre, Roraima, Matto Grosso, and within almost every municipality of Amazonas state, it is believed that pollution of the urban stream and river systems prevents the development of the simuliid vectors of and explains the parasite's reduced distribution within urban areas and an absence of recent reports from the state capital Manaus. Decades of WHO-led periodic ivermectin treatment of Yanomami tribe's people have resulted in the partial suppression of transmission in this focus and has also probably affected the transmission of in the region. , and very probably infections can all be treated and most likely cured with a 4-6-week treatment course of doxycycline. The Brazilian Ministry of Health does not, however, presently recommend any treatment for mansonellosis infections and thus parasitic infections outside the Amazonia focus are typically left untreated. While the long treatment courses required for doxycycline-based mansonellosis therapies preclude their use in control programmes, new fast-acting filarial drug treatments are likely to soon become available for the treatment of both onchocerciasis and mansonellosis in the Amazon region. Filarial disease management in the Brazilian Amazon is thus likely to become dramatically more viable at a time when the public health importance of these diseases is increasingly being recognized.
PubMed: 38283060
DOI: 10.1016/j.crpvbd.2023.100168 -
Balkan Medical Journal Mar 2024Anemia remains a significant public health concern in Gabon, particularly among children, adolescents, and females. Gabon is also home to two major species of filarial...
BACKGROUND
Anemia remains a significant public health concern in Gabon, particularly among children, adolescents, and females. Gabon is also home to two major species of filarial worms, and spp., which cause microfilaremia. The epidemiological nexus between hemoglobin (Hb) concentrations and microfilaremia in Gabonese first-time blood donors remains unknown.
AIMS
To understand better the epidemiological relationship between anemia and microfilaremia to improve donor selection and management protocols.
STUDY DESIGN
A retrospective cohort study.
METHODS
This study was conducted among first-time blood donors in Lambaréné between March 2018 and October 2019. Participants aged 16-65 years old and weighing a minimum of 50 kg were enrolled using standard donor selection criteria. An automatic hematological analyzer was used to quantify Hb concentrations, and microscopy techniques were used to detect the presence of microfilariae.
RESULTS
Microfilariae were found in 4.8% (35/723) of the 723 first-time blood donors from Lambaréné. Anemia was classified as mild in 35.5% (257/723) and moderate in 1% (7/723). No significant associations were found between the distribution of microfilariae and variables such as age, sex, socioprofessional classification, marital status, or residence. Blood group O donors had a higher prevalence of microfilariae (6%) than non-O donors (2.7%). However, the observed difference was not statistically significant (AOR =2.3, = 0.052). Furthermore, microfilariae were associated with increased moderate anemia (3.7% vs. 29%, AOR =15.6, = 0.003).
CONCLUSION
Our findings highlight microfilaremia as a possible etiological cause of anemia among Gabonese blood donors, emphasizing the need for further research and a potential review of donor management strategies.
Topics: Child; Animals; Female; Adolescent; Humans; Young Adult; Adult; Middle Aged; Aged; Microfilariae; Loiasis; Blood Donors; Gabon; Prevalence; Retrospective Studies; Anemia
PubMed: 38259115
DOI: 10.4274/balkanmedj.galenos.2023.2023-9-86 -
Current Research in Parasitology &... 2024The genus Faust, 1929 includes 29 species, mainly parasites of platyrrhine monkeys in South America and anthropoid apes in Africa. In Malaysia, () (Mullin & Orihel,...
Redescription, molecular characterisation and endosymbionts of () (Mullin & Orihel, 1972) (Spirurida: Onchocercidae) from the common treeshrew Diard & Duvaucel (Mammalia: Scandentia) in Peninsular Malaysia.
The genus Faust, 1929 includes 29 species, mainly parasites of platyrrhine monkeys in South America and anthropoid apes in Africa. In Malaysia, () (Mullin & Orihel, 1972) was described from the common treeshrew Diard & Duvaucel (Scandentia). In a recent classification of the genus , seven subgenera were proposed, with . (.) as a monotypic species in the subgenus . In this study, we collected new material of . (.) from common treeshrews in Peninsular Malaysia and redescribed the morphological features of this species. We found that . (.) differs from . () Uni et al., 2004 from sika deer (Cetartiodactyla) in Japan, with regards to morphological features and predilection sites in their respective hosts. Based on multi-locus sequence analyses, we examined the molecular phylogeny of . (.) and its genotype. Species of the genus grouped monophyletically in clade ONC5 and . (.) was placed in the most derived position within this genus. (.) was closely related to . (.) (Manson, 1897) from humans in Central and South America, and most distant from . (.) . The calculated p-distances between the 1 gene sequences for . (.) and its congeners were 13.09% for . () and 15.6-16.15% for . (.) . The molecular phylogeny of spp. thus corroborates their morphological differences. We determined that . (.) harbours endosymbionts of the supergroup F genotype, in keeping with all other species screened to date.
PubMed: 38193019
DOI: 10.1016/j.crpvbd.2023.100154 -
Parasites & Vectors Dec 2023Loiasis is endemic in the northern and western part of the Republic of Congo. Between 2004 and 2010, surveys were conducted, using the RAPLOA method, in all departments...
BACKGROUND
Loiasis is endemic in the northern and western part of the Republic of Congo. Between 2004 and 2010, surveys were conducted, using the RAPLOA method, in all departments of the Republic of Congo to assess the distribution of loiasis. Prior to 2004, only two parasitological surveys on loiasis had been conducted in Congo and mainly in the Department of Lékoumou, in the southwestern of the country. In 2019, we conducted a parasitological survey in this same department, more than 30 years after the first surveys.
METHODS
The study was conducted in 21 villages. Loa loa and Mansonella perstans microfilaremia levels were quantified using 50 µl calibrated blood smears.
RESULTS
A total of 2444 individuals were examined. The median age of the screened individuals was 43 (interquartile range: 30-57, range: 18-91) years old. The overall prevalences of L. loa and M. perstans microfilaremia were 20.0% [95% confidence intervals (CI) 18.0-21.6%] and 1.0% (95% CI 0.6-1.4%) respectively. The proportion of individuals with a microfilarial density of L. loa > 8000 mf/ml and > 30,000 mf/ml were 5.1% (95% CI 4.3-6.1%) and 1.1% (95% CI 0.8-1.7%), respectively. The overall community microfilarial load was 3.4 mf/ml.
CONCLUSIONS
Prevalences and intensities of L. loa infection remained generally stable between the late 1980s and 2019 in the Lékoumou Department. In contrast, parasitological indicators for M. perstans have declined sharply in the intervening years for an unknown reason.
Topics: Animals; Humans; Adult; Middle Aged; Mansonella; Loiasis; Mansonelliasis; Loa; Congo; Prevalence; Microfilariae
PubMed: 38071391
DOI: 10.1186/s13071-023-06056-w