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Emerging Infectious Diseases Nov 2019We reviewed Giemsa-stained thick blood smears, obtained through the national malaria surveillance program in the Amazon region of Ecuador, by light microscopy for...
We reviewed Giemsa-stained thick blood smears, obtained through the national malaria surveillance program in the Amazon region of Ecuador, by light microscopy for Mansonella spp. microfilariae. Of 2,756 slides examined, 566 (20.5%) were positive. Nested PCR confirmed that the microfilariae were those of M. ozzardi nematodes, indicating that this parasite is endemic to this region.
Topics: Animals; Ecuador; Female; Geography, Medical; Humans; Male; Mansonella; Mansonelliasis; Polymerase Chain Reaction; Prevalence; Public Health Surveillance
PubMed: 31625843
DOI: 10.3201/eid2511.181964 -
PloS One 2019Vector-borne pathogens are a significant public health concern worldwide. Infections with these pathogens, some of which are emerging, are likely under-recognized due to...
BACKGROUND
Vector-borne pathogens are a significant public health concern worldwide. Infections with these pathogens, some of which are emerging, are likely under-recognized due to the lack of widely-available laboratory tests. There is an urgent need for further advancement in diagnostic modalities to detect new and known vector-borne pathogens. We evaluated the utility of metagenomic shotgun sequencing (MGS) as a pathogen agnostic approach for detecting vector-borne pathogens from human blood samples.
METHODS
Residual whole blood samples from patients with known infection with Babesia microti, Borrelia hermsii, Plasmodium falciparum, Mansonella perstans, Anaplasma phagocytophilum or Ehrlichia chaffeensis were studied. Samples underwent DNA extraction, removal of human DNA, whole genome amplification, and paired-end library preparation, followed by sequencing on Illumina HiSeq 2500. Bioinformatic analysis was performed using the Livermore Metagenomics Analysis Toolkit (LMAT), Metagenomic Phylogenetic Analysis (MetaPhlAn2), Genomic Origin Through Taxonomic CHAllenge (GOTTCHA) and Kraken 2.
RESULTS
Eight samples were included in the study (2 samples each for P. falciparum and A. phagocytophilum). An average of 27.5 million read pairs was generated per sample (range, 18.3-38.8 million) prior to removal of human reads. At least one of the analytic tools was able to detect four of six organisms at the genus level, and the organism present in five of eight specimens at the species level. Mansonella and Ehrlichia species were not detected by any of the tools; however, mitochondrial cytochrome c oxidase subunit I amino acid sequence analysis suggested the presence of M. perstans genetic material.
CONCLUSIONS
MGS is a promising tool with the potential to evolve as a non-hypothesis driven diagnostic test to detect vector-borne pathogens, including protozoa and helminths.
Topics: Animals; Disease Vectors; Genes, Mitochondrial; Humans; Infections; Metagenomics; Phylogeny; Sequence Analysis, DNA; Species Specificity
PubMed: 31577814
DOI: 10.1371/journal.pone.0222915 -
Journal of Clinical Microbiology Oct 2019The morphologic similarities of the microfilariae and their infrequency in clinical specimens in settings of endemicity present challenges to clinical laboratories in... (Review)
Review
The morphologic similarities of the microfilariae and their infrequency in clinical specimens in settings of endemicity present challenges to clinical laboratories in maintaining competence for accurate identification and differentiation. We present here a review of the primary filarial nematodes causing human infection, including an illustrated key, which we hope will improve the diagnostic capabilities of hematologists, microbiologists, medical technologists, and similarly qualified laboratorians.
Topics: Animals; Humans; Immunoassay; Life Cycle Stages; Microfilariae; Microscopy; Molecular Diagnostic Techniques; Nematode Infections; Specimen Handling
PubMed: 31340993
DOI: 10.1128/JCM.00706-19 -
Scientific Reports Jul 2019Mansonelliasis is a widespread yet neglected tropical infection of humans in Africa and South America caused by the filarial nematodes, Mansonella perstans, M. ozzardi,...
Mansonelliasis is a widespread yet neglected tropical infection of humans in Africa and South America caused by the filarial nematodes, Mansonella perstans, M. ozzardi, M. rodhaini and M. streptocerca. Clinical symptoms are non-distinct and diagnosis mainly relies on the detection of microfilariae in skin or blood. Species-specific DNA repeat sequences have been used as highly sensitive biomarkers for filarial nematodes. We have developed a bioinformatic pipeline to mine Illumina reads obtained from sequencing M. perstans and M. ozzardi genomic DNA for new repeat biomarker candidates which were used to develop loop-mediated isothermal amplification (LAMP) diagnostic tests. The M. perstans assay based on the Mp419 repeat has a limit of detection of 0.1 pg, equivalent of 1/1000 of a microfilaria, while the M. ozzardi assay based on the Mo2 repeat can detect as little as 0.01 pg. Both LAMP tests possess remarkable species-specificity as they did not amplify non-target DNAs from closely related filarial species, human or vectors. We show that both assays perform successfully on infected human samples. Additionally, we demonstrate the suitability of Mp419 to detect M. perstans infection in Culicoides midges. These new tools are field deployable and suitable for the surveillance of these understudied filarial infections.
Topics: Africa; Animals; Computer Simulation; DNA, Protozoan; Diagnostic Tests, Routine; Female; Genetic Markers; High-Throughput Nucleotide Sequencing; Humans; Male; Mansonella; Mansonelliasis; Molecular Diagnostic Techniques; Neglected Diseases; Nucleic Acid Amplification Techniques; Repetitive Sequences, Nucleic Acid; Sensitivity and Specificity; Sequence Analysis, DNA; South America
PubMed: 31311985
DOI: 10.1038/s41598-019-46550-9 -
The American Journal of Tropical... Jul 2019Treating is challenged by the low efficacy of registered antihelminthics. endobacteria provide an alternative treatment target because depletion results in... (Randomized Controlled Trial)
Randomized Controlled Trial
Treating is challenged by the low efficacy of registered antihelminthics. endobacteria provide an alternative treatment target because depletion results in amicrofilaremia in filarial infections with and infections. This open-label, randomized study sought to confirm that i) are present in in Ghana and ii) doxycycline treatment will deplete and cause a slow, sustained decline in microfilariae (MF). Two hundred and two Ghanaians with infection were randomized into early (immediate) and delayed (6 months deferred) treatment groups, given doxycycline 200 mg/day for 6 weeks, and monitored for MF and levels at baseline, 4, 12, and 24 months after the study onset (= time of randomization and start of treatment for the early group). Per protocol analysis revealed that the median MF/mL in the early group declined from 138 at baseline to 64 at month 4 and further to 0 at month 12. In the delayed group, MF load did not change from a baseline median of 97 to 102 at month 4 but declined to 42 at month 12, that is, 6 months after receiving treatment, trailing the early group as expected. By month 24, both treatment groups had reached a median MF level of 0. After treatment, were depleted from MF by ≥ 1-log drop compared with baseline levels. We conclude that in Ghana harbor that are effectively depleted by doxycycline with subsequent reduction in MF loads, most likely because of interruption of fertility of adult worms.
Topics: Adolescent; Adult; Animals; Anti-Bacterial Agents; Child; Doxycycline; Female; Ghana; Humans; Male; Mansonella; Mansonelliasis; Middle Aged; Young Adult
PubMed: 31162017
DOI: 10.4269/ajtmh.18-0491 -
Parasites & Vectors Apr 2019Culicoides (Diptera; Ceratoponidae) are tiny, stout, blood-sucking flies with a near worldwide distribution. When present, they are often considered a biting nuisance...
BACKGROUND
Culicoides (Diptera; Ceratoponidae) are tiny, stout, blood-sucking flies with a near worldwide distribution. When present, they are often considered a biting nuisance but in addition, they are involved in the transmission of pathogens to humans, domestic and wild animals. Data on Culicoides species in the South-West region of Cameroon dates back to the 1950s. Over the decades, ecological transformation due to agriculture and deforestation may have affected the population dynamics of Culicoides and therefore our study provides an update of their bio-ecology in the region. Furthermore, the role of various Culicoides species in the transmission of parasitic filariae of the genus Mansonella remains inconclusive in this region. This study was designed to address these unknown issues and expand on current scientific knowledge.
RESULTS
Eight species of Culicoides (C. bedfordi, C. inornatipennis, C. fulvithorax, C. grahamii, C. imicola, C. milnei, C. neavei and C. kumbaensis) were collected using light traps and human baits. Culicoides grahamii was the most abundant species, followed closely by C. milnei. Three species (C. milnei, C. grahamii and C. inornatipennis) were common in all observed larval development sites. Only four species (C. inornatipennis, C. fulvithorax, C. grahamii and C. milnei) were collected on humans. Anthropophilic species were more abundant (P < 0.001) in the evening (4-7 pm) when compared to the morning collections (6-9 am). After overnight fly collections using a drop trap with a human microfilaremic donor, C. milnei emerged as the potential host for transmitting Mansonella perstans. Substantial heterogeneity was observed between the trap visiting cycles of the various species (P < 0.001). The biting cycle of the main vector, C. milnei, showed two peaks (10-11 pm and 4-5 am), the highest being 10-11 pm.
CONCLUSIONS
The Culicoides fauna of the South-West region of Cameroon has not changed significantly since the 1950s. Culicoides milnei was demonstrated to be the major vector of M. perstans in this part of Cameroon. It is essentially a nocturnal species which peaks in abundance between 10 and 11 pm.
Topics: Animals; Biodiversity; Cameroon; Ceratopogonidae; Female; Humans; Insect Vectors; Male; Mansonella; Mansonelliasis
PubMed: 30975194
DOI: 10.1186/s13071-019-3432-9 -
The American Journal of Tropical... Apr 2019Infections due to and are common yet elusive neglected filariases. Parasitological cure after treatment is very difficult to assess, as adult parasites are not... (Observational Study)
Observational Study
Infections due to and are common yet elusive neglected filariases. Parasitological cure after treatment is very difficult to assess, as adult parasites are not accessible. Therefore, outside transmission areas, patients require a long follow-up period to ascertain the therapeutic outcome, which is impractical for non-sedentary populations such as migrants. We studied the change over time of microfilaremia, eosinophil counts, and antifilarial antibodies tested with a commercial ELISA test (Bordier Affinity Products, Crissier, Switzerland), in a retrospective cohort of patients with confirmed and infections, to evaluate the role of serology in clinical practice. After treatment, all 22 eligible patients diagnosed in our center between 2015 and 2017 reached amicrofilaremia, with microfilarial counts decreasing sharply within 2 months. Paralleling eosinophil counts, antibodies decreased in all patients, 36% of whom reached sero-reversion or near-sero-reversion in < 20 months. These findings suggest that positive serology is not just residual from a past infection, and may be used for diagnosis even when microfilaremia is negative or cannot be performed. Interestingly, antibodies and eosinophil counts increased following some, but not all, re-treatment courses. If the rise in these parameters reflects death of macrofilariae, caution is required in interpreting high eosinophil counts and antibody titers shortly after treatment, as these may reflect no need for further treatment. To optimize patients' management, it is now pivotal to ascertain the interval between treatment and macrofilarial death and therefore whether re-treatments are required for complete clearance of parasites.
Topics: Adolescent; Adult; Animals; Antibodies, Helminth; Enzyme-Linked Immunosorbent Assay; Eosinophils; Female; Filaricides; Follow-Up Studies; Humans; Italy; Leukocyte Count; Loa; Loiasis; Longitudinal Studies; Male; Mansonella; Mansonelliasis; Microfilariae; Middle Aged; Retrospective Studies; Young Adult
PubMed: 30693861
DOI: 10.4269/ajtmh.18-0693 -
Clinical and Experimental Immunology Apr 2019Mansonella perstans (Mp) filariasis is present in large populations in sub-Saharan Africa, and to what extent patent Mp infection modulates the expression of immunity in...
Mansonella perstans (Mp) filariasis is present in large populations in sub-Saharan Africa, and to what extent patent Mp infection modulates the expression of immunity in patients, notably their cellular cytokine and chemokine response profile, remains not well known. We studied the spontaneous and inducible cellular production of chemokines (C-X-C motif) ligand 9 (CXCL9) [monokine induced by interferon (IFN)-γ (MIG)], CXCL-10 [inducible protein (IP)-10], chemokine (C-C motif) ligand 24 (CCL24) (eotaxin-2), CCL22 [macrophage-derived chemokine (MDC)], CCL13 [monocyte chemotactic protein-4 (MCP-4)], CCL18 [pulmonary and activation-regulated chemokine (PARC)], CCL17 [thymus- and activation-regulated chemokine (TARC)] and interleukin (IL)-27 in mansonelliasis patients (Mp-PAT) and mansonelliasis-free controls (CTRL). Freshly isolated peripheral mononuclear blood cells (PBMC) were stimulated with helminth, protozoan and bacterial antigens and mitogen [phytohaemagglutinin (PHA)]. PBMC from Mp-PAT produced spontaneously (without antigen stimulation) significantly higher levels of eotaxin-2, IL-27, IL-8, MCP-4 and MDC than cells from CTRL, while IFN-γ-IP-10 was lower in Mp-PAT. Helminth antigens activated IL-27 and MCP-4 only in CTRL, while Ascaris antigen, Onchocerca antigen, Schistosoma antigen, Entamoeba antigen, Streptococcus antigen, Mycobacteria antigen and PHA stimulated MIG release in CTRL and Mp-PAT. Notably, Entamoeba antigen and PHA strongly depressed (P < 0·0001) eotaxin-2 (CCL24) production in both study groups. Multiple regression analyses disclosed in Mp-PAT and CTRL dissimilar cellular chemokine and cytokine production levels being higher in Mp-PAT for CCL24, IL-27, IL-8, MCP-4, MDC and PARC (for all P < 0·0001), at baseline (P < 0·0001), in response to Entamoeba histolytica strain HM1 antigen (EhAg) (P < 0·0001), Onchocerca volvulus adult worm-derived antigen (OvAg) (P = 0·005), PHA (P < 0·0001) and purified protein derivative (PPD) (P < 0·0001) stimulation. In Mp-PAT with hookworm co-infection, the cellular chemokine production of CXCL10 (IP-10) was diminished. In summary, the chemokine and cytokine responses in Mp-PAT were in general not depressed, PBMC from Mp-PAT produced spontaneously and selectively inducible inflammatory and regulatory chemokines and cytokines at higher levels than CTRL and such diverse and distinctive reactivity supports that patent M. perstans infection will not polarize innate and adaptive cellular immune responsiveness in patients.
Topics: Adaptive Immunity; Africa South of the Sahara; Animals; Antigens, Bacterial; Antigens, Helminth; Cells, Cultured; Chemokines; Cytokines; Filariasis; Humans; Immunity, Innate; Interleukin-27; Leukocytes, Mononuclear; Mansonella; Mansonelliasis
PubMed: 30561772
DOI: 10.1111/cei.13251 -
New Microbes and New Infections Nov 2018Human mansonellosis is caused by and the three main filarial species in the genus Despite accumulating evidence of a high prevalence in endemic areas, there is... (Review)
Review
Human mansonellosis is caused by and the three main filarial species in the genus Despite accumulating evidence of a high prevalence in endemic areas, there is currently no filariasis control programme targeting mansonellosis. The health-related impact on people living with these filariae remains unknown, and evidences regarding treatment strategies are scarce. Like other neglected diseases, it mainly affects poor populations living in tropical and subtropical climates. Mansonellosis can be considered one of the most neglected tropical infectious diseases. The objective of this literature review was to draw attention to the gap of knowledge regarding spp. taxonomy, the transmission of these arthropod-borne filariasis and the health outcomes of people living with mansonellosis.
PubMed: 30402239
DOI: 10.1016/j.nmni.2018.08.016 -
Research and Reports in Tropical... 2018Mansonellosis is a filarial disease caused by three species of filarial (nematode) parasites (, , and ) that use humans as their main definitive hosts. These parasites... (Review)
Review
Mansonellosis is a filarial disease caused by three species of filarial (nematode) parasites (, , and ) that use humans as their main definitive hosts. These parasites are transmitted from person to person by bloodsucking females from two families of flies (Diptera). Biting midges (Ceratopogonidae) transmit all three species of , but blackflies (Simuliidae) are also known to play a role in the transmission of in parts of Latin America. and are endemic in western, eastern, and central Africa, and is also present in the neotropical region from equatorial Brazil to the Caribbean coast. has a patchy distribution in Latin America and the Caribbean. Mansonellosis infections are thought to have little pathogenicity and to be almost always asymptomatic, but occasionally causing itching, joint pains, enlarged lymph glands, and vague abdominal symptoms. In Brazil, infections are also associated with corneal lesions. Diagnosis is usually performed by detecting microfilariae in peripheral blood or skin without any periodicity. There is no standard treatment at present for mansonellosis. The combination therapy of diethylcarbamazine plus mebendazole for microfilaremia is presently one of the most widely used, but the use of ivermectin has also been proven to be very effective against microfilariae. Recently, doxycycline has shown excellent efficacy and safety when used as an antimicrobial against endosymbiotic bacteria harbored by some strains of and . Diethylcarbamazine and ivermectin have been used effectively to treat infection. There are at present no estimates of the disease burden caused by mansonellosis, and thus its importance to many global health professionals and policy makers is presently limited to how it can interfere with diagnostic tools used in modern filarial disease control and elimination programs aimed at other species of filariae.
PubMed: 30050351
DOI: 10.2147/RRTM.S125750