RESUMEN
BACKGROUND: Although there is unprecedented interest in experimental human hookworm infection, details of hookworm manufacture and characterisation have been sparsely reported. In this report, we detail the production and characterisation of Necator americanus larvae for use in a recently published clinical trial. METHODS: Faeces was obtained from an experimentally infected donor. Faecal hookworm DNA was determined by quantitative PCR. Paired samples were incubated in either sterile water or sterile water mixed with antimicrobials (amphotericin and gentamicin). Coproculture was performed by modified Harada-Mori method. The harvested larvae were then processed in either sterile water or antiseptic solution. Larval yield was then calculated (larvae per gram), larval viability was determined by thermally induced motility assay and microbial burden was determined at the day of harvest, at 48 h and at 7 days. RESULTS: Twenty-eight faecal cultures were performed over 16 months. The faecal hookworm DNA content was variable over this time. There was no association of larval yield with faecal hookworm DNA content. Pre-treatment of faeces with antimicrobials did not influence larval yield. Larval motility was 85.3% (95% CI 79.3-91.3%). Incubation of larvae in antiseptics did not reduce viability at 14 days with a marginal mean of 68.6% (95% CI 59.1-78.1%) washed in water vs. 63.3% (95% CI 53.8 - 72.9%) when incubated in betadine (p = 0.38). Larvae washed in sterile water did not meet microbial bioburden criteria. Incubation in antiseptic resulted in acceptable microbial bioburden at 48 h but not at 7 days. Although the addition of gentamicin did reduce the microbial bio-burden acceptable levels, it was found to significantly lower larval motility at 7 days compared to incubation in sterile water and motility at 7 days 37.8% (95% CI 4.7-70.9%) vs. 67.3% (95% CI 35.2-99.3%, p < 0.001), respectively. CONCLUSIONS: Despite standardised culture methodologies and the use of a single donor, larval yield varied considerably between batches and had no association with faecal hookworm DNA. Larval viability decreases over time and the age of larvae at time of use are likely to be important. Microbial bioburden maybe temporarily reduced by incubation in antiseptics and has little effect on viability. Incubation of larvae in gentamicin is effective at reducing microbial bioburden but is deleterious to larval viability.
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Antiinfecciosos Locales , Infecciones por Uncinaria , Necatoriasis , Ancylostomatoidea , Animales , Antiinfecciosos Locales/uso terapéutico , Gentamicinas/farmacología , Gentamicinas/uso terapéutico , Humanos , Larva , Necator , Necator americanus , Necatoriasis/tratamiento farmacológico , AguaRESUMEN
BACKGROUND: Bacterial infections are responsible of high economic losses in aquaculture. Mexican golden trout (Oncorhynchus chrysogaster) is a threatened native trout species that has been introduced in aquaculture both for species conservation and breeding for production and for which no studies of bacterial infections have been reported. CASE PRESENTATION: Fish from juvenile stages of Mexican golden trout showed an infectious outbreak in a farm in co-culture with rainbow trout (Oncorhynchus mykiss), showing external puntiform red lesions around the mouth and caudal pedunculus resembling furuncles by Aeromonas spp. and causing an accumulated mortality of 91%. Isolation and molecular identification of bacteria from lesions and internal organs showed the presence of Aeromonas bestiarum, Aeromonas sobria, Plesiomonas shigelloides and Ichthyobodo necator isolated from a single individual. All bacterial isolates were resistant to amoxicillin-clavulanic acid and cefazoline. P. shigelloides was resistant to third generation ß-lactamics. CONCLUSIONS: This is the first report of coinfection by Aeromonas bestiarum, Aeromonas sobria, Plesiomonas shigelloides and Ichthyobodo necator in an individual of Mexican golden trout in co-culture with rainbow trout. Resistance to ß-lactams suggests the acquisition of genetic determinants from water contamination by human- or livestock-associated activities.
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Aeromonas , Coinfección , Enfermedades de los Peces , Infecciones por Bacterias Gramnegativas , Oncorhynchus mykiss , Oncorhynchus , Parásitos , Plesiomonas , Aeromonas/genética , Animales , Coinfección/veterinaria , Enfermedades de los Peces/microbiología , Infecciones por Bacterias Gramnegativas/microbiología , Infecciones por Bacterias Gramnegativas/veterinaria , Necator , Plesiomonas/genéticaRESUMEN
Various host and parasite factors interact to determine the outcome of infection. We investigated the effects of two factors on the within-host dynamics of malaria in mice: initial infectious dose and co-infection with a helminth that limits the availability of red blood cells (RBCs). Using a statistical, time-series approach to model the within-host 'epidemiology' of malaria, we found that increasing initial dose reduced the time to peak cell-to-cell parasite propagation, but also reduced its magnitude, while helminth co-infection delayed peak cell-to-cell propagation, except at the highest malaria doses. Using a mechanistic model of within-host infection dynamics, we identified dose-dependence in parameters describing host responses to malaria infection and uncovered a plausible explanation of the observed differences in single vs co-infections. Specifically, in co-infections, our model predicted a higher background death rate of RBCs. However, at the highest dose, when intraspecific competition between malaria parasites would be highest, these effects of co-infection were not observed. Such interactions between initial dose and co-infection, although difficult to predict a priori, are key to understanding variation in the severity of disease experienced by hosts and could inform studies of malaria transmission dynamics in nature, where co-infection and low doses are the norm.
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Coinfección/parasitología , Malaria/parasitología , Necator/fisiología , Necatoriasis/parasitología , Plasmodium chabaudi/fisiología , Animales , Ratones , Ratones Endogámicos BALB CRESUMEN
Grapevine powdery mildew (GPM), caused by the fungus Erysiphe necator, is a constant threat to worldwide production of grape berries, requiring repeated use of fungicides for management. The frequent fungicide applications have resulted in resistance to commonly used quinone outside inhibitor (QoI) fungicides and the resistance is associated with single-nucleotide polymorphisms (SNPs) in the mitochondrial cytochrome b gene (cytb). In this study, we attempted to detect the most common SNP causing a glycine to alanine substitution at amino acid position 143 (i.e., G143A) in the cytb protein, to track this resistance using allele-specific TaqMan probe and digital-droplet PCR-based assays. Specificity and sensitivity of these assays showed that these two assays could discriminate SNPs and were effective on mixed samples. These diagnostic assays were implemented to survey E. necator samples collected from leaf and air samples from California and Oregon grape-growing regions. Sequencing of PCR amplicons and phenotyping of isolates also revealed that these assays accurately detected each allele (100% agreement), and there was an absolute agreement between the presence or absence of the G143A mutation and resistance to QoIs in the E. necator sampled. These results indicate that the developed diagnostic tools will help growers make informed decisions about fungicide selections and applications which, in turn, will facilitate GPM disease management and improve grape production systems.
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Ascomicetos , Fungicidas Industriales , Alelos , Animales , Ascomicetos/genética , Farmacorresistencia Fúngica/genética , Erysiphe , Granjas , Fungicidas Industriales/farmacología , Necator , QuinonasRESUMEN
BACKGROUND: The Onchocercidae is a family of filarial nematodes with several species of medical or veterinary importance. Microfilariae are found in the blood and/or the dermis and are usually diagnosed in humans by microscopy examination of a blood sample or skin biopsy. The main objectives of this study were to evaluate whether filariae DNA can be detected in faecal samples of wild non-human primates (NHPs), whether the detected parasites were closely related to those infecting humans and whether filarial DNA detection in faeces is associated with co-infections with nematodes (Oesophagostumum sp. and Necator sp.) known to cause blood loss while feeding on the host intestinal mucosa. METHODS: A total of 315 faecal samples from 6 species of NHPs from Cameroon and Gabon were analysed. PCRs targeted DNA fragments of cox1 and 12S rDNA genes, to detect the presence of filariae, and the internal transcribed spacer 2 (ITS2), to detect the presence of Oesophagostomum sp. and Necator sp. infections. RESULTS: Among the 315 samples analysed, 121 produced sequences with > 90% homology with Onchocercidae reference sequences. However, 63% of the 12S rDNA and 78% of the cox1 gene sequences were exploitable for phylogenetic analyses and the amplification of the 12S rDNA gene showed less discriminating power than the amplification of the cox1 fragment. Phylogenetic analyses showed that the cox1 sequences obtained from five chimpanzee DNA faecal samples from Gabon and two from Cameroon cluster together with Mansonella perstans with high bootstrap support. Most of the remaining sequences clustered together within the genus Mansonella, but the species could not be resolved. Among the NHP species investigated, a significant association between filarial DNA detection and Oesophagostomum sp. and Necator sp. infection was observed only in gorillas. CONCLUSIONS: To our knowledge, this is the first study reporting DNA from Mansonella spp. in faecal samples. Our results raise questions about the diversity and abundance of these parasites in wildlife, their role as sylvatic reservoirs and their potential for zoonotic transmission. Future studies should focus on detecting variants circulating in both human and NHPs, and improve the molecular information to resolve or support taxonomy classification based on morphological descriptions.
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Heces/parasitología , Mansonella/genética , Mansoneliasis/veterinaria , Necator/clasificación , Oesophagostomum/clasificación , Primates/parasitología , Animales , Camerún , Ciclooxigenasa 1/genética , ADN de Helmintos/genética , Pruebas con Sangre Seca , Gabón , Genotipo , Necator/genética , Oesophagostomum/genética , FilogeniaRESUMEN
The close phylogenetic relationship between humans and nonhuman primates (NHPs) can result in a high potential for pathogen exchange. In recent decades, NHP and human interactions have become more frequent due to increasing habitat encroachment and ecotourism. Strongylid communities, which include members of several genera, are typically found in NHPs. Using optimized high-throughput sequencing for strain-level identification of primate strongylids, we studied the structure of strongylid communities in NHPs and humans co-habiting a tropical forest ecosystem in the Central African Republic. General taxonomic assignment of 85 ITS-2 haplotypes indicated that the studied primates harbour at least nine genera of strongylid nematodes, with Oesophagostomum and Necator being the most prevalent. We detected both host-specific and shared strongylid haplotypes. Skin-penetrating Necator gorillaehaplotypes were shared between humans and gorillas but Necator americanus were much more restricted to humans. Strongylid communities of local hunter-gatherers employed as trackers were more similar to those of gorillas compared to their relatives, who spent more time in villages. This was due to lower abundance of human-origin N. americanus in both gorillas and trackers. Habituated gorillas or those under habituation did not show larger overlap of strongylids with humans compared to unhabituated. We concluded that the occurrence of the human-specific strongylids in gorillas does not increase with direct contact between gorillas and humans due to the habituation. Overall, our results indicate that the degree of habitat sharing between hosts, together with mode of parasite transmission, are important factors for parasite spillover among primates.
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Variación Genética/genética , Primates/genética , Simpatría/genética , Animales , Ecosistema , Gorilla gorilla/genética , Humanos , Necator/genética , Oesophagostomum/genética , FilogeniaRESUMEN
Infection with gastrointestinal parasitic nematodes is a major cause of chronic morbidity and economic burden around the world, particularly in low-resource settings. Some parasitic nematode species, including the human-parasitic threadworm Strongyloides stercoralis and human-parasitic hookworms in the genera Ancylostoma and Necator, feature a soil-dwelling infective larval stage that seeks out hosts for infection using a variety of host-emitted sensory cues. Here, we review our current understanding of the behavioral responses of soil-dwelling infective larvae to host-emitted sensory cues, and the molecular and cellular mechanisms that mediate these responses. We also discuss the development of methods for transgenesis and CRISPR/Cas9-mediated targeted mutagenesis in Strongyloides stercoralis and the closely related rat parasite Strongyloides ratti. These methods have established S. stercoralis and S. ratti as genetic model systems for gastrointestinal parasitic nematodes and are enabling more detailed investigations into the neural mechanisms that underlie the sensory-driven behaviors of this medically and economically important class of parasites.
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Interacciones Huésped-Parásitos , Nematodos/fisiología , Infecciones por Nematodos/transmisión , Sensación , Suelo/parasitología , Ancylostoma/fisiología , Anquilostomiasis/parasitología , Anquilostomiasis/transmisión , Animales , Enfermedades Gastrointestinales/parasitología , Humanos , Larva/fisiología , Necator/fisiología , Infecciones por Nematodos/parasitología , Ratas , Strongyloides ratti/fisiología , Strongyloides stercoralis/fisiologíaRESUMEN
Soil-transmitted helminthiasis (STH) is caused by Ascaris lumbricoides (roundworm), Trichuris trichiura (whipworm), and Ancylostoma duodenale and Necator americanus (hookworms). Mebendazole is one of the recommended preventive chemotherapy agents for STH. This review summarizes the efficacy data from 29 studies with single-dose 500 mg mebendazole in STH treatment and compares the results with those of a recently conducted phase 3 study of a 500 mg mebendazole chewable tablet against A. lumbricoides and T. trichiura infections. Studies that reported efficacy results against at least one STH infection were selected from the literature and efficacy data by each STH type were abstracted and pooled. Single-dose 500 mg mebendazole treatment resulted in a cure rate of 92.6% (range: 72.5-100%) for A. lumbricoides, 27.6% (range: 8.4-100%) for T. trichiura and 25.5% (range: 2.9-91.1%) for hookworms. Egg reduction rate for A. lumbricoides was 97.9% (range: 89.8-100%), for T. trichiura it was 72.9% (range: 31.6-93.0%) and for hookworms it was 72.0% (range: -6.5% (denoting an increase in egg count) to 98.3%). Similar results were observed in the studies that were placebo-controlled. In the phase 3 study, the cure rate and egg reduction rate reported was 83.7% and 97.9%, respectively, for A. lumbricoides and 33.9% and 59.7%, respectively, for T. trichiura. In conclusion, single-dose 500 mg mebendazole showed a high cure rate against A. lumbricoides and a substantial reduction in faecal egg count for all STH types. These results are consistent with the recently conducted phase 3 study of a new 500 mg chewable mebendazole tablet.
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Helmintiasis/tratamiento farmacológico , Helmintiasis/transmisión , Mebendazol/administración & dosificación , Infecciones por Nematodos/tratamiento farmacológico , Suelo/parasitología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Ancylostoma/efectos de los fármacos , Animales , Antihelmínticos/administración & dosificación , Antihelmínticos/uso terapéutico , Ascaris lumbricoides/efectos de los fármacos , Niño , Preescolar , Ensayos Clínicos Fase III como Asunto , Heces/parasitología , Helmintiasis/parasitología , Humanos , Mebendazol/uso terapéutico , Persona de Mediana Edad , Necator/efectos de los fármacos , Infecciones por Nematodos/parasitología , Recuento de Huevos de Parásitos , Ensayos Clínicos Controlados Aleatorios como Asunto , Tricuriasis/tratamiento farmacológico , Trichuris/efectos de los fármacos , Adulto JovenRESUMEN
BACKGROUND: Although a high genetic diversity of Plasmodium spp. circulating in great apes has been revealed recently due to non-invasive methods enabling detection in faecal samples, little is known about the actual mechanisms underlying the presence of Plasmodium DNA in faeces. Great apes are commonly infected by strongylid nematodes, including hookworms, which cause intestinal bleeding. The impact of strongylid infections on the detection of Plasmodium DNA in faeces was assessed in wild, western, lowland gorillas from Dzanga Sangha Protected Areas, Central African Republic and eastern chimpanzees from Kalinzu Forest Reserve, Uganda. METHODS: Fifty-one faecal samples from 22 habituated gorillas and 74 samples from 15 habituated chimpanzees were analysed using Cytochrome-b PCR assay and coprological methods. RESULTS: Overall, 26.4% of the analysed samples were positive for both Plasmodium spp. and strongylids. However, the results showed no significant impact of intensity of infections of strongylids on detection of Plasmodium DNA in gorilla and chimpanzee faeces. CONCLUSION: Bleeding caused by strongylid nematode Necator spp. cannot explain the presence of Plasmodium DNA in ape faeces.
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Enfermedades del Simio Antropoideo/epidemiología , Gorilla gorilla , Malaria/veterinaria , Pan troglodytes , Plasmodium/aislamiento & purificación , Ancylostoma/fisiología , Anquilostomiasis/parasitología , Animales , Enfermedades del Simio Antropoideo/parasitología , República Centroafricana/epidemiología , ADN Protozoario/análisis , Heces/química , Malaria/epidemiología , Malaria/parasitología , Necator/fisiología , Necatoriasis/parasitología , Uganda/epidemiologíaRESUMEN
Species composition of Necator hookworms was surveyed in (i) Ugandan chimpanzees living around farms and villages at Bulindi, (ii) Gabonese gorillas under habituation in Moukalaba-Doudou National Park (MDNP), and (iii) Gabonese villagers living adjacent to MDNP. Internal transcribed spacers (ITS) of rDNA and partial cytochrome c oxidase subunit 1 (Cox1) gene of mtDNA were analyzed from larvae obtained by coproculture. Three ITS types (I, II and III) and three Cox1 haplotype groups (A, B and C) were demonstrated. ITS type I and Cox1 haplotype group A, representing Necator americanus, were demonstrated in the hookworm larvae from Gabonese gorillas and humans, but not from Ugandan chimpanzees. Type II and haplotype groups B and C, presumably representing N. gorillae, were found in larvae from Ugandan chimpanzees and Gabonese gorillas and humans. These features were overall similar with those found previously in the Central African Republic. Meanwhile, type III was proven in a larva from a Gabonese gorilla as the first demonstration from a non-human primate. Cox1 haplotypes obtained from Ugandan chimpanzees formed a subgroup within group B, presumably reflecting dispersal and diversification processes of the apes.
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Heces/parasitología , Gorilla gorilla/parasitología , Necator/genética , Necator/fisiología , Pan troglodytes/parasitología , Animales , Enfermedades del Simio Antropoideo/parasitología , Ciclooxigenasa 1/genética , Conducta Alimentaria , Gabón , Haplotipos , Humanos , Larva/genética , Larva/crecimiento & desarrollo , Necator/aislamiento & purificación , Necator americanus/genética , Necator americanus/aislamiento & purificación , Necator americanus/fisiología , Necatoriasis/parasitología , Necatoriasis/veterinaria , Estaciones del Año , Análisis de Secuencia de ADN , UgandaRESUMEN
Hookworm infection is still prevalent in southern Thailand despite control measures. Hookworm eggs submerged for an extended period under water from rainfall or in latrines may not survive, but they may recover their ability to develop into infective larvae when exposed to atmospheric air. This study examined the survival of the hookworm eggs in stool suspension and the restoration of development capability after prolonged storage. In stool mass, eggs developed normally and yielded infective filariform larvae (FL) in 7 days. On the contrary, in 1:10 stool suspension, hookworm eggs were found to remain at the 4-8 cell stage; degenerated eggs were observed after 15 days of storage, and the number of degenerated eggs reached 80 % on day 30. Aeration of the suspension, or transferring to a Petri dish or agar plate, restored the capacity of eggs stored for up to 15 days to develop into FL; thereafter, the capacity declined sharply. Retardation of egg development under water or in stool suspension may be due to a lack of atmospheric air. Use of "night soil" from latrines as fertilizer may be one factor in maintaining hookworm transmission, as worm eggs can undergo normal development upon exposure to atmospheric air.
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Ancylostomatoidea/crecimiento & desarrollo , Heces/parasitología , Infecciones por Uncinaria/parasitología , Necator/crecimiento & desarrollo , Necatoriasis/parasitología , Preservación Biológica/métodos , Ancylostomatoidea/patogenicidad , Animales , Femenino , Infecciones por Uncinaria/epidemiología , Infecciones por Uncinaria/transmisión , Humanos , Larva , Necator/patogenicidad , Necatoriasis/epidemiología , Necatoriasis/transmisión , Óvulo/crecimiento & desarrollo , Preservación Biológica/normas , Prevalencia , Suelo/parasitología , Suspensiones , Tailandia/epidemiología , Agua/parasitologíaRESUMEN
BACKGROUND: In general, studies on the diversity of strongylid nematodes in endangered host species are complicated as material obtained by non-invasive sampling methods has limited value for generic and species identification. While egg morphology barely allows assignment to family, the morphology of cultivated infective third stage larvae provides a better resolution at the generic level but cannot be used for exact species identification. Morphology-based taxonomic approaches greatly depend on the examination of adult worms that are usually not available. METHODS: Hookworm parasites in two European researchers, who participated in gorilla research in the Central African Republic, were expelled after anthelmintic treatment to the faeces, collected and morphologically examined. A male worm discharged naturally from a wild bonobo (Pan paniscus) in Congo was also examined for comparison. RESULTS: Two species of Necator were identified in researchers' faecal material: Necator americanus (Stiles, 1902) and N. gorillae Noda & Yamada, 1964; the latter species differed in having a smaller body, smaller buccal cavity and shorter spicules with spade-shaped membranes situated distally. Males of N. gorillae also possessed unusual cuticular thickenings on the dorsal side of the prebursal region of the body. These characters, shared with the male worm from the bonobo, correspond well to the description of N. gorillae described from gorillas in Congo. CONCLUSIONS: Based on the morphology of the hookworms recovered in this study and previous molecular analyses of larvae developed from both humans and western lowland gorillas (Gorilla gorilla gorilla) from this locality, we conclude that the researchers became infected with gorilla hookworms during their stay in the field. This is the first report of infection with a Necator species other than N. americanus in humans.
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Necator/aislamiento & purificación , Necatoriasis/epidemiología , Exposición Profesional , Investigadores , Adulto , Animales , República Centroafricana , Gorilla gorilla , Humanos , Necatoriasis/parasitologíaRESUMEN
BACKGROUND: Hookworms are important pathogens of humans. To date, Necator americanus is the sole, known species of the genus Necator infecting humans. In contrast, several Necator species have been described in African great apes and other primates. It has not yet been determined whether primate-originating Necator species are also parasitic in humans. METHODOLOGY/PRINCIPAL FINDINGS: The infective larvae of Necator spp. were developed using modified Harada-Mori filter-paper cultures from faeces of humans and great apes inhabiting Dzanga-Sangha Protected Areas, Central African Republic. The first and second internal transcribed spacers (ITS-1 and ITS-2) of nuclear ribosomal DNA and partial cytochrome c oxidase subunit 1 (cox1) gene of mtDNA obtained from the hookworm larvae were sequenced and compared. Three sequence types (I-III) were recognized in the ITS region, and 34 cox1 haplotypes represented three phylogenetic groups (A-C). The combinations determined were I-A, II-B, II-C, III-B and III-C. Combination I-A, corresponding to N. americanus, was demonstrated in humans and western lowland gorillas; II-B and II-C were observed in humans, western lowland gorillas and chimpanzees; III-B and III-C were found only in humans. Pairwise nucleotide difference in the cox1 haplotypes between the groups was more than 8%, while the difference within each group was less than 2.1%. CONCLUSIONS/SIGNIFICANCE: The distinctness of ITS sequence variants and high number of pairwise nucleotide differences among cox1 variants indicate the possible presence of several species of Necator in both humans and great apes. We conclude that Necator hookworms are shared by humans and great apes co-habiting the same tropical forest ecosystems.
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Ecosistema , Necator/clasificación , Necator/aislamiento & purificación , Necatoriasis/parasitología , Necatoriasis/veterinaria , Árboles , Animales , República Centroafricana/epidemiología , Análisis por Conglomerados , ADN Espaciador Ribosómico/química , ADN Espaciador Ribosómico/genética , Complejo IV de Transporte de Electrones/genética , Genotipo , Humanos , Epidemiología Molecular , Datos de Secuencia Molecular , Necator/genética , Necatoriasis/epidemiología , Pan troglodytes , Filogenia , Enfermedades de los Primates/epidemiología , Enfermedades de los Primates/parasitología , Primates , Análisis de Secuencia de ADN , Homología de SecuenciaRESUMEN
BACKGROUND: Hookworm infections are still endemic in low and middle income tropical countries with greater impact on the socioeconomic and public health of the bottom billion of the world's poorest people. In this study, a real-time polymerase chain reaction (PCR) coupled with high resolution melting-curve (HRM) analysis was evaluated for an accurate, rapid and sensitive tool for species identification focusing on the five human hookworm species. METHODS: Real-time PCR coupled with HRM analysis targeting the second internal transcribed spacer (ITS-2) of nuclear ribosomal DNA as the genetic marker was used to identify and distinguish hookworm species in human samples. Unique and distinct characteristics of HRM patterns were produced for each of the five hookworm species. The melting curves were characterized by peaks of 79.24±0.05°C and 83.00±0.04°C for Necator americanus, 79.12±0.10°C for Ancylostoma duodenale, 79.40±0.10°C for Ancylostoma ceylanicum, 79.63±0.05°C for Ancylostoma caninum and 79.70±0.14°C for Ancylostoma braziliense. An evaluation of the method's sensitivity and specificity revealed that this assay was able to detect as low as 0.01 ng/µl hookworm DNA and amplification was only recorded for hookworm positive samples. CONCLUSION: The HRM assay developed in this study is a rapid and straightforward method for the diagnosis, identification and discrimination of five human hookworms. This assay is simple compared to other probe-based genotyping methods as it does not require multiplexing, DNA sequencing or post-PCR processing. Therefore, this method offers a new alternative for rapid detection of human hookworm species.
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ADN Intergénico/química , Infecciones por Uncinaria/diagnóstico , Desnaturalización de Ácido Nucleico , Ancylostoma/genética , Ancylostoma/aislamiento & purificación , Ancylostoma/patogenicidad , Animales , Cartilla de ADN/genética , ADN Intergénico/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Marcadores Genéticos/genética , Humanos , Necator/genética , Necator/aislamiento & purificación , Necator/patogenicidad , Sensibilidad y Especificidad , Factores de TiempoRESUMEN
Introducción: malaria, parasitosis intestinales y desnutrición coexisten e interactúan en los habitantes de las zonas palúdicas; se requiere conocer la magnitud de cada una de esas enfermedades. Objetivo: identificar la prevalencia de parásitos intestinales en niños (4-10 años) de Urabá y Bajo Cauca (Antioquia, Colombia) y conocer el cambio postratamiento antiparasitario intestinal específico. Metodología: en niños con paludismo, se hicieron encuestas parasitarias intestinales antes y 8 y 30 días postratamiento (albendazol + secnidazol). Se usaron coprológicos directo y por concentración, en muestra única. Resultados: el día-1, 80% mostraron algún helminto patógeno y 39%, algún protozoo patógeno; hubo helmintos y protozoos patógenos en 35%. Las prevalencias específicas el día 1 fueron: Ascaris lumbricoides 43,5%, Trichuris trichiura 68,2%, Necator americanus 37,6%, Entamoeba histolytica 15,3%, Giardia lamblia 21,2%. La intensidad parasitaria protozoaria fue siempre baja (1-2 cruces) y por helmintos fue moderada-intensa en 84% para A. lumbricoides, 83% para T. trichiura y 50% para N. americanus. Medida el día 8, la reducción neta de la prevalencia protozoaria, atribuible al tratamiento, fue: E. histolytica 50%, G. lamblia 71% (p < 0,05). Medida el día 8, la reducción neta de la intensidad de helmintos, atribuible al tratamiento, fue significativa para A. limbricoides y N. americanus. La reducción neta por el albendazol medida al día 8 fue: A. lumbricoides 91%, N. americanus 87%, T. trichiura 27%; siempre fue significativa la reducción de la cantidad de huevos (p < 0,05). Conclusión: las parasitosis intestinales en Turbo y El Bagre, en niños maláricos de 4-10 años, tienen muy alta prevalencia y constituyen un grave problema de salud pública.
Introduction: Malaria, intestinal parasitoses and malnutrition coexist and interact in people of malarious areas; it is required to know the magnitude of these diseases. Objective: to identify the prevalence of intestinal parasites in children (aged 4-10 years) of malarious areas of Antioquia (northwestern Colombia), and to know the changes of parasites at days 8 and 30 after specific treatment. Methodology: intestinal parasites surveys were applied before treatment (albendazole + secnidazole) and at days 8 and 30 after treatment. Examination of stools (direct and concentration) were used in single samples. Results: at day 1, 80% of the children showed some pathogenic helminth, 39% had some pathogenic protozoan, and 35% had both helminths and protozoa. Specific prevalences at day 1 were as follows: Ascaris lumbricoides 43.5%, Trichuris trichiura 68.2%, Necator americanus 37.6%, Entamoeba histolytica, 15.3%, Giardia lamblia 21.2%. The intensity of infection was slight (1-2 crosses) for protozoan parasites and it was moderateintense for helminth parasites, namely: 84% for A. lumbricoides, 83% for T. trichiura and 50% for N. americanus. The net effect on protozoan prevalence attributable to treatment, measured at day 8, was E. histolytica 50% and G. lamblia 71% (p < 0.05). The net effect on helminth burden (NEHB) attributable to treatment (between days 1 and 8) was significant for A. lumbricoides and N. americanus. The NEHB of albendazole, measured at day 8, was 91% for A. lumbricoides, 27% for T. trichiura and 87% for N. americanus. Egg reduction was always significant (p < 0.05). Conclusion: Prevalence rates of intestinal parasites in Turbo and El Bagre, in children with malaria, aged 4-10 years, are still high and constitute a severe public health problem.
Asunto(s)
Ascaris , Entamoeba , Giardia , Malaria , Necator , Niño , Strongyloides , TrichurisRESUMEN
En climas templados, yungas (zona intermedia entre valle y trópico) y trópico, prevalecen dos parásitos hematófagos: Necator americanusy Ancylostoma duodenale, responsable de una anemia crónica, que lleva a los niños a tener niveles tan bajos de Hb, que a veces sonconsiderados incompatibles con la vida; rara vez originan sangrado agudo severo.Describimos el caso de un niño, de seis meses de edad, procedente de Coroico (Nor Yungas) con disentería inicial, misma que luego secomplica con melenas y rectorragia de sangre rutilante que origina una hipovolemia severa, rayana en el choque. Sometido a exploraciónquirúrgica por persistencia del sangrado, previo gammagrafía para descartar un divertículo de Meckel, no se halla el sitio de sangradopor lo que se realiza laparotomía exploratoria y posteriormente una endoscopía, identifi cándose en duodeno foco de sangrado originadopor parásitos, que por su morfología se asume que se trate de Necator americanus. Con este diagnóstico, recibe transfusiones para suestabilizar su hipovolemia y Mebendazol, con buena evolución, remisión del sangrado de tubo digestivo, y buena tolerancia a la alimentación.El sangrado agudo por uncinarias, es excepcional, hecho que justifi ca la presentación del caso y permite realizar un recordatorio breve delos mecanismos responsables de ello...
In temperate climate, yungas (intermediate zone between valley and tropical lowland), two blood sucking parasites are prevalent: Necator americanus and Ancylostoma duodenale, responsible for chronic anaemia in children that causes extremely low Hb levels sometimesconsidered as incompatible with life; only in rare cases acute bleeding occurs.We describe the case of a six months old child stemming from Coroico (Nor Yungas) initially with dysentery that becomes complicated by melaena and rectal bleeding originating severe hypovolaemia bordering on shock. After gammagraphy in order to exclude Meckels diverticle, the child was submitted to surgical exploration, where no source of bleeding could be found, therefore an explorative laparotomy was performed and later on an endoscopy, where the source of bleeding was identifi ed in the duodenum as caused by the parasite Necator Americanus. With this diagnose, blood transfusions were administered to the child in order to stabilize the hypovolaemia and Mebendazol was given. The evolution was good, the bleeding stopped and feeding was well tolerated.Acute bleeding caused by hook worms is exceptional; therefore we present this case as a short reminder of the responsible mechanisms.
Asunto(s)
Humanos , Masculino , Lactante , Hipovolemia/cirugía , Hipovolemia/etiología , Hipovolemia/fisiopatología , Necator/clasificación , Necator/crecimiento & desarrollo , Necator/parasitologíaRESUMEN
Epidemiological studies suggest that a hookworm infection producing 50 eggs/gram of feces may protect against asthma. We conducted a dose-ranging study to identify the dose of hookworm larvae necessary to achieve 50 eggs/gram of feces for therapeutic trials of asthma. Ten healthy subjects without asthma or airway hyperresponsiveness to inhaled methacholine received 10, 25, 50, or 100 Necator americanus larvae administered double blind to an area of skin on the arm. Subjects were seen weekly for 12 weeks and were then treated with mebendazole. Skin itching at the entry site and gastrointestinal symptoms were common at higher doses. Lung function did not change. Levels of blood eosinophils and IgE increased transiently, and levels of IgG increased progressively. All doses resulted in at least 50 eggs/gram of feces in the eight subjects who completed the study. Infection with 10 N. americanus larvae is well tolerated, elicits a modest host eosinophil response, and is potentially suitable for use in preliminary clinical therapeutic trials.
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Antígenos Helmínticos/inmunología , Asma/prevención & control , Necator/fisiología , Recuento de Huevos de Parásitos , Adulto , Animales , Asma/parasitología , Asma/terapia , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Evaluación de Medicamentos , Humanos , Larva/metabolismo , Recuento de Leucocitos , Persona de Mediana Edad , Necator/inmunología , Necatoriasis/fisiopatología , Resultado del TratamientoRESUMEN
Schistosoma japonicum has been related to anemia, but the mechanisms mediating this relationship remain unresolved. The primary objective of this study was to assess the role of occult blood loss in mediating S. japonicum-associated anemia after adjusting for age, sex, socioeconomic status (SES), and other helminth infections. The secondary objective was to identify intensity categories of risk for occult blood loss for Trichuris and hookworm after adjustment for the presence of other helminth infections. The role of occult blood loss in mediating S. japonicum-associated anemia was studied cross-sectionally in 729 individuals 8-30 years old in Leyte, The Philippines. Three stool specimens were examined in duplicate for helminth eggs. Hemoglobin, fecal occult blood loss, and anemia were measured and related to the presence and intensity of helminths. Multivariate models were made to adjust for confounding by other helminths and SES. In multivariate models, hemoglobin significantly decreased with increasing infection intensity of S. japonicum, hookworm, and T. trichuria (P < 0.0031, P < 0.0001, and P < 0.0001, respectively). Individuals with higher intensities S. japonicum and T. trichuria were significantly more likely to be fecal occult positive (odds ratio [OR] = 3.54; P = 0.008 and OR = 2.68; P = 0.013, respectively), although this was not true for individuals with hookworm. Additionally, individuals with higher intensities of S. japonicum, hookworm, and T. trichuria were all more likely to be anemic (OR = 3.7, P = 0.0002; OR = 5.3, P = 0.0003; and OR = 1.6, P = 0.021, respectively). It is likely that occult blood loss plays a role only at heavier intensity S. japonicum infections and some other mechanism, such as anemia of inflammation, may be contributing to anemia.
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Anemia Ferropénica/epidemiología , Esquistosomiasis Japónica/epidemiología , Adolescente , Adulto , Anemia Ferropénica/etiología , Anemia Ferropénica/parasitología , Animales , Ascaris/aislamiento & purificación , Niño , Estudios Transversales , Enfermedades Endémicas , Heces/parasitología , Femenino , Helmintiasis/complicaciones , Helmintiasis/epidemiología , Helmintiasis/parasitología , Humanos , Masculino , Necator/aislamiento & purificación , Sangre Oculta , Filipinas/epidemiología , Prevalencia , Factores de Riesgo , Schistosoma japonicum/aislamiento & purificación , Esquistosomiasis Japónica/complicaciones , Esquistosomiasis Japónica/parasitología , Factores Socioeconómicos , Trichuris/aislamiento & purificaciónAsunto(s)
Infecciones por Uncinaria , Adolescente , Adulto , Anciano , Ancylostoma/crecimiento & desarrollo , Animales , Antihelmínticos/uso terapéutico , Bencimidazoles/uso terapéutico , Niño , Preescolar , Costo de Enfermedad , Emigración e Inmigración , Femenino , Infecciones por Uncinaria/epidemiología , Infecciones por Uncinaria/fisiopatología , Infecciones por Uncinaria/prevención & control , Humanos , Lactante , Larva Migrans , Estadios del Ciclo de Vida , Masculino , Persona de Mediana Edad , Necator/crecimiento & desarrollo , Instituciones Académicas , ViajeRESUMEN
Hookworm is an important intestinal parasite infection with high prevalence in tropical countries. In addition to iron deficiency anaemia, the human hookworm appears to have evolved a number of complementary strategies to overcome the host's haemostatic processes. These include the inhibition of blood coagulation, platelet aggregation and mediator release, and the secretion of fibrinogenolytic enzymes. In this work, we studied the platelets in the subjects with detection of hookworm infection from screening stool examination comparing to those without. One hundred subjects were included, studied for stool parasite and platelet parameters. Of our 100 subjects, hookworms were identified in stools of six cases, giving an infection rate equal to 6%. The platelet parameters of the subjects showed a statistically significant lowering of mean platelet volume (MPV) in the subjects with hookworm infection. Also, we detected a non-significant lower platelet count in subjects with hookworm infections. Of interest, the alteration in platelet size, identified by platelet parameters, has never been documented in the literature. This observation might be a pathological process or might be an accidental finding in our study.