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PLoS Neglected Tropical Diseases Apr 2019Human hookworms (Necator americanus, Ancylostoma duodenale, and Ancylostoma ceylanicum) are intestinal blood-feeding parasites that infect ~500 million people worldwide...
BACKGROUND
Human hookworms (Necator americanus, Ancylostoma duodenale, and Ancylostoma ceylanicum) are intestinal blood-feeding parasites that infect ~500 million people worldwide and are among the leading causes of iron-deficiency anemia in the developing world. Drugs are useful against hookworm infections, but hookworms rapidly reinfect people, and the parasites can develop drug resistance. Therefore, having a hookworm vaccine would be of tremendous benefit.
METHODOLOGY/PRINCIPAL FINDINGS
We investigated the vaccine efficacy in outbred Syrian hamsters of three A. ceylanicum hookworm antigen candidates from two classes of proteins previously identified as promising vaccine candidates. These include two intestinally-enriched, putatively secreted cathepsin B cysteine proteases (AceyCP1, AceyCPL) and one small Kunitz-type protease inhibitor (AceySKPI3). Recombinant proteins were produced in Pichia pastoris, and adsorbed to Alhydrogel. Recombinant AceyCPL (rAceyCPL)/Alhydrogel and rAceySKPI3/Alhydrogel induced high serum immunoglobulin G (IgG) titers in 8/8 vaccinates, but were not protective. rAceyCP1/Alhydrogel induced intermediate serum IgG titers in ~60% of vaccinates in two different trials. rAceyCP1 serum IgG responders had highly significantly decreased hookworm burdens, fecal egg counts and clinical pathology compared to Alhydrogel controls and nonresponders. Protection was highly correlated with rAceyCP1 serum IgG titer. Antisera from rAceyCP1 serum IgG responders, but not nonresponders or rAceyCPL/Alhydrogel vaccinates, significantly reduced adult A. ceylanicum motility in vitro. Furthermore, rAceyCP1 serum IgG responders had canonical Th2-specific recall responses (IL4, IL5, IL13) in splenocytes stimulated ex vivo.
CONCLUSIONS/SIGNIFICANCE
These findings indicate that rAceyCP1 is a promising vaccine candidate and validates a genomic/transcriptomic approach to human hookworm vaccine discovery.
Topics: Amino Acid Sequence; Ancylostoma; Ancylostomiasis; Animals; Antibodies, Helminth; Antigens, Helminth; Antigens, Surface; Cysteine Proteases; Disease Models, Animal; Immunoglobulin G; Intestinal Diseases, Parasitic; Male; Mesocricetus; Recombinant Proteins; Vaccination; Vaccines; Vaccines, Synthetic
PubMed: 31009474
DOI: 10.1371/journal.pntd.0007345 -
Revista Do Instituto de Medicina... 2011The aim of this study was to determine the frequency and intensity of Ancylostoma spp. in 33 dogs and 52 cats by means of coproparasitological examinations and...
The aim of this study was to determine the frequency and intensity of Ancylostoma spp. in 33 dogs and 52 cats by means of coproparasitological examinations and parasitological necropsy, and assess the presence of contaminated feces with eggs of that parasite in public places of Andradina Municipality, São Paulo State, Brazil. Willis-Mollay and Sedimentation methods indicated Ancylostoma spp. eggs in 87.8% (29/33) dogs and 94.2% (49/52) cats. The species A. caninum and A. braziliense were found in 63.6% (21/33) and 30.3% (10/33) of dogs, respectively. Considering cats, 67.3% (35/52) were parasitized by A. braziliense, 21.1% (11/52) by A. caninum, and 9.6% (5/52) by A. tubaeforme. Forty-two canine fecal samples were collected from public environments, including 23 squares/gardens and 19 streets/sidewalks. Positive samples for Ancylostoma spp. accounted for 64.3% (27/42); squares/gardens had 60.9% (14/23) positive samples, and streets and sidewalks, 68.4% (13/19). No association was observed between the number of Ancylostoma spp parasites and age, sex and breed of the animals and also the ratio of EPG counts and the parasitic intensity observed at necropsy (p > 0.05). Based on the high occurrence of hookworm in dogs and cats in this study, the treatment with anti helminthics are needed even in those animals with negative stool tests, besides adopting control of the number of animals in public places, in order to decrease the likelihood of environmental contamination, since this parasite represents a potential hazard to human and animal health.
Topics: Age Factors; Ancylostoma; Ancylostomiasis; Animals; Brazil; Cat Diseases; Cats; Cities; Dog Diseases; Dogs; Feces; Female; Helminths; Humans; Male; Parasite Egg Count; Public Facilities
PubMed: 21915459
DOI: 10.1590/s0036-46652011000400001 -
Frontiers in Veterinary Science 2021is a zoonotic nematode which is able to affect animals and humans. Diagnosis in the definitive host and environmental detection are key to prevent its dissemination and...
is a zoonotic nematode which is able to affect animals and humans. Diagnosis in the definitive host and environmental detection are key to prevent its dissemination and achieve control. Herein, a new coprological LAMP method for the detection of (Copro-LAMPAc) DNA was developed. DNA extraction was performed using a low-cost method and a fragment of the -1 gene was used for primer design. The analytical sensitivity, evaluated with serial dilutions of genomic DNA from adult worms, was 100 fg. A specificity of 100% was obtained using genomic DNA from the host and other pathogens. The Copro-LAMPAc was evaluated using environmental canine fecal samples. When compared with gold standard optical microscopy in epidemiological studies, it proved to be more sensitive. This new LAMP assay can provide an alternative protocol for screening and identification of for epidemiological studies in endemic areas.
PubMed: 34869740
DOI: 10.3389/fvets.2021.770508 -
Revista Do Instituto de Medicina... 2014This study aims to assess the association between schistosomiasis and hookworm infection with hemoglobin levels of schoolchildren in northern Mozambique. Through a...
This study aims to assess the association between schistosomiasis and hookworm infection with hemoglobin levels of schoolchildren in northern Mozambique. Through a cross-sectional survey, 1,015 children from five to 12 years old in the provinces of Nampula, Cabo Delgado and Niassa were studied. Hookworm infection and urinary schistosomiasis were diagnosed, through Ritchie and filtration methods, with a prevalence of 31.3% and 59.1%, respectively. Hemoglobin levels were obtained with a portable photometer (Hemocue®). The average hemoglobin concentration was 10.8 ± 1.42 g/dL, and 62.1% of the children presented levels below 11.5 g/dL, of which 11.8% of the total number of children had hemoglobin levels below 9 g/dL. A multiple linear regression analysis demonstrated negative interactions between hemoglobin levels and ancylostomiasis, this being restricted to the province of Cabo Delgado (β = -0.55; p < 0.001) where an independent interaction between hemoglobin levels and urinary schistosomiasis was also observed (β = -0.35; p = 0.016). The logistical regression model indicated that hookworm infection represents a predictor of mild (OR = 1.87; 95% CI = 1.17-3.00) and moderate/severe anemia (OR = 2.71; 95% CI = 1.50 - 4.89). We concluded that, in the province of Cabo Delgado, hookworm and Schistosoma haematobium infections negatively influence hemoglobin levels in schoolchildren. Periodical deworming should be considered in the region. Health education and improvements in sanitary infrastructure could achieve long-term and sustainable reductions in soil-transmitted helminthiases and schistosomiasis prevalence rates.
Topics: Anemia; Animals; Child; Child, Preschool; Female; Hemoglobin A; Hookworm Infections; Humans; Male; Mozambique; Schistosomiasis haematobia; Severity of Illness Index
PubMed: 24879000
DOI: 10.1590/s0036-46652014000300007 -
The American Journal of Tropical... Feb 2011Polymerase chain reaction (PCR) assays for intestinal parasites are increasingly being used on fecal DNA samples for enhanced specificity and sensitivity of detection....
Polymerase chain reaction (PCR) assays for intestinal parasites are increasingly being used on fecal DNA samples for enhanced specificity and sensitivity of detection. Comparison of these tests against microscopy and copro-antigen detection has been favorable, and substitution of PCR-based assays for the ova and parasite stool examination is a foreseeable goal for the near future. One challenge is the diverse list of protozoan and helminth parasites. Several existing real-time PCR assays for the major intestinal parasites-Cryptosporidium spp., Giardia intestinalis, Entamoeba histolytica, Ancylostoma duodenale, Ascaris lumbricoides, Necator americanus, and Strongyloides stercoralis-were adapted into a high throughput protocol. The assay involves two multiplex PCR reactions, one with specific primers for the protozoa and one with specific primers for the helminths, after which PCR products are hybridized to beads linked to internal oligonucleotide probes and detected on a Luminex platform. When compared with the parent multiplex real-time PCR assays, this multiplex PCR-bead assay afforded between 83% and 100% sensitivity and specificity on a total of 319 clinical specimens. In conclusion, this multiplex PCR-bead protocol provides a sensitive diagnostic screen for a large panel of intestinal parasites.
Topics: Ancylostoma; Ancylostomiasis; Animals; Ascariasis; Ascaris lumbricoides; Child, Preschool; Cryptosporidiosis; Cryptosporidium; DNA, Protozoan; Dysentery, Amebic; Entamoeba histolytica; Entamoebiasis; Feces; Giardia lamblia; Giardiasis; Humans; Intestinal Diseases, Parasitic; Necator americanus; Necatoriasis; Polymerase Chain Reaction; Sensitivity and Specificity; Strongyloides stercoralis; Strongyloidiasis
PubMed: 21292910
DOI: 10.4269/ajtmh.2011.10-0461 -
Historia, Ciencias, Saude--Manguinhos Dec 2015The pharmacist Theodoro Peckolt was one of the most important figures in the history of the chemistry of natural Brazilian products. Like other nineteenth-century...
The pharmacist Theodoro Peckolt was one of the most important figures in the history of the chemistry of natural Brazilian products. Like other nineteenth-century pharmacists in Brazil, he developed formulations and sold them at his pharmacy in Rio de Janeiro, and these enjoyed great prestige in the eyes both of the public and the medical community. The article discusses the relation between the illness originally called "opilação" (ancylostomiasis, or hookworm) and nineteenth-century treatment. It focuses especially on Peckolt Pharmacy's "Doliarina and iron powder," a formulation extracted from the Ficus gomelleira rubber plant. One of the article's goals is to use modern methods to analyze Ficus gomelleira and identify the chemical composition of the drug.
Topics: Animals; Antinematodal Agents; Brazil; Ficus; History, 19th Century; Hookworm Infections; Humans; Iron; Pharmacies; Pharmacists
PubMed: 26625923
DOI: 10.1590/S0104-59702015000400012 -
Mitochondrial DNA. Part B, Resources Sep 2019The dog hookworm (Nematoda, Ancylostomatidae) is a blood-feeding intestinal parasitic nematode and can cause ancylostomiasis in humans. In this study, the complete...
The dog hookworm (Nematoda, Ancylostomatidae) is a blood-feeding intestinal parasitic nematode and can cause ancylostomiasis in humans. In this study, the complete mitochondrial genome of this anthropozoonotic hookworm was sequenced through Illumina deep sequencing technology. The whole genome was 13,721 bp in length and encoded 36 genes including 12 protein-coding genes, 22 transfer RNAs, and 2 ribosomal RNAs. Phylogeny revealed that grouped with species from Ancylostomatinae and separated from species of Bunostominae in the family Ancylostomatidae. Amongst the subfamily Ancylostomatinae, three dog-originated , regardless of isolate origins, clustered together and were more closely related to the cat hookworm and the human hookworm than to the dog/cat hookworm and the sea lion hookworm . Taken together, the cumulative mitochondrial DNA data provides insights into phylogenetic studies among Ancylostomatidae nematodes.
PubMed: 33365829
DOI: 10.1080/23802359.2019.1666048 -
International Journal For Parasitology.... Aug 2020Ancylostoma caninum is the most prevalent intestinal nematode of dogs, and has a zoonotic potential. Multiple-drug resistance (MDR) has been confirmed in a number of A....
Ancylostoma caninum is the most prevalent intestinal nematode of dogs, and has a zoonotic potential. Multiple-drug resistance (MDR) has been confirmed in a number of A. caninum isolates, including isolate Worthy 4.1F3P, against all anthelmintic drug classes approved for hookworm treatment in dogs in the United States (US). The cyclooctadepsipeptide emodepside is not registered to use in dogs in the US, but in a number of other countries/regions. The objective of this study was to evaluate the efficacy of emodepside + praziquantel, as well as three commercial products that are commonly used in the US for treatment of hookworms, against a suspected (subsequently confirmed) MDR A. caninum isolate Worthy 4.1F3P. 40 dogs infected on study day (SD) 0 with 300 third-stage larvae, were randomly allocated to one of five treatment groups with eight dogs each: pyrantel pamoate (Nemex®-2), fenbendazole (Panacur® C), milbemycin oxime (Interceptor®), emodepside + praziquantel tablets and non-treated control. Fecal egg counts (FEC) were performed on SDs 19, 20, 22, 27, 31 and 34. All treatments were administered as per label requirements on SD 24 to dogs in Groups 1 through 4. Two additional treatments were administered on SDs 25 and 26 to dogs in Group 2 as per label requirements. Dogs were necropsied on SD 34 and the digestive tract was removed/processed for worm recovery and enumeration. The geometric mean (GM) worm counts for the control group was 97.4, and for the pyrantel pamoate, fenbendazole, milbemycin oxime, and emodepside + praziquantel groups were 74.8, 72.0, 88.9, and 0.4, respectively. These yielded efficacies of 23.2%, 26.1%, and 8.8%, and 99.6%, respectively. These data support previous findings of the MDR status of Worthy 4.1F3P as treatments with pyrantel pamoate, fenbendazole and milbemycin oxime lacked efficacy. In sharp contrast, Worthy 4.1F3P was highly susceptible to treatment with emodepside + praziquantel.
Topics: Ancylostomatoidea; Ancylostomiasis; Animals; Anthelmintics; Depsipeptides; Dog Diseases; Dogs; Drug Combinations; Drug Resistance, Multiple; Hookworm Infections; Intestines; Macrolides; Praziquantel; Pyrantel; Treatment Outcome
PubMed: 32403053
DOI: 10.1016/j.ijpddr.2020.04.003 -
PLoS Neglected Tropical Diseases 2012Hookworm infections are an important cause of (severe) anemia and iron deficiency in children in the tropics. Type of hookworm species (Ancylostoma duodenale or Necator...
BACKGROUND
Hookworm infections are an important cause of (severe) anemia and iron deficiency in children in the tropics. Type of hookworm species (Ancylostoma duodenale or Necator americanus) and infection load are considered associated with disease burden, although these parameters are rarely assessed due to limitations of currently used diagnostic methods. Using multiplex real-time PCR, we evaluated hookworm species-specific prevalence, infection load and their contribution towards severe anemia and iron deficiency in pre-school children in Malawi.
METHODOLOGY AND FINDINGS
A. duodenale and N. americanus DNA loads were determined in 830 fecal samples of pre-school children participating in a case control study investigating severe anemia. Using multiplex real-time PCR, hookworm infections were found in 34.1% of the severely anemic cases and in 27.0% of the non-severely anemic controls (p<0.05) whereas a 5.6% hookworm prevalence was detected by microscopy. Prevalence of A. duodenale and N. americanus was 26.1% and 4.9% respectively. Moderate and high load A. duodenale infections were positively associated with severe anemia (adjusted odds ratio: 2.49 (95%CI 1.16-5.33) and 9.04 (95%CI 2.52-32.47) respectively). Iron deficiency (assessed through bone marrow examination) was positively associated with intensity of A. duodenale infection (adjusted odds ratio: 3.63 (95%CI 1.18-11.20); 16.98 (95%CI 3.88-74.35) and 44.91 (95%CI 5.23-385.77) for low, moderate and high load respectively).
CONCLUSIONS/SIGNIFICANCE
This is the first report assessing the association of hookworm load and species differentiation with severe anemia and bone marrow iron deficiency. By revealing a much higher than expected prevalence of A. duodenale and its significant and load-dependent association with severe anemia and iron deficiency in pre-school children in Malawi, we demonstrated the need for quantitative and species-specific screening of hookworm infections. Multiplex real-time PCR is a powerful diagnostic tool for public health research to combat (severe) anemia and iron deficiency in children living in resource poor settings.
Topics: Ancylostoma; Ancylostomiasis; Anemia; Animals; Child, Preschool; Female; Humans; Infant; Iron Deficiencies; Malawi; Male; Multiplex Polymerase Chain Reaction; Necator americanus; Parasite Load; Prevalence; Real-Time Polymerase Chain Reaction
PubMed: 22514750
DOI: 10.1371/journal.pntd.0001555 -
Invertebrate Neuroscience : IN Sep 2019Parasitic nematode infections are treated using anthelmintic drugs, some of which target nicotinic acetylcholine receptors (nAChRs) located in different parasite...
Parasitic nematode infections are treated using anthelmintic drugs, some of which target nicotinic acetylcholine receptors (nAChRs) located in different parasite tissues. The limited arsenal of anthelmintic agents and the prevalence of drug resistance imply that future defense against parasitic infections will depend on the discovery of novel targets and therapeutics. Previous studies have suggested that Ascaris suum ACR-16 nAChRs are a suitable target for the development of antinematodal drugs. In this study, we characterized the pharmacology of the Ancylostoma caninum ACR-16 receptor using two-electrode voltage-clamp electrophysiology. This technique allowed us to study the effects of cholinergic agonists and antagonists on the nematode nAChRs expressed in Xenopus laevis oocytes. Aca-ACR-16 was not sensitive to many of the existing cholinomimetic anthelmintics (levamisole, oxantel, pyrantel, and tribendimidine). 3-Bromocytisine was the most potent agonist (> 130% of the control acetylcholine current) on the Aca-ACR-16 nAChR but, unlike Asu-ACR-16, oxantel did not activate the receptor. The mean time constants of desensitization for agonists on Aca-ACR-16 were longer than the rates observed in Asu-ACR-16. In contrast to Asu-ACR-16, the A. caninum receptor was completely inhibited by DHβE and moderately inhibited by α-BTX. In conclusion, we have successfully reconstituted a fully functional homomeric nAChR, ACR-16, from A. caninum, a model for human hookworm infections. The pharmacology of the receptor is distinct from levamisole-sensitive nematode receptors. The ACR-16 homologue also displayed some pharmacological differences from Asu-ACR-16. Hence, A. caninum ACR-16 may be a valid target site for the development of anthelmintics against hookworm infections.
Topics: Ancylostoma; Ancylostomiasis; Animals; Anthelmintics; Cholinergic Agents; Helminth Proteins; Receptors, Nicotinic
PubMed: 31486912
DOI: 10.1007/s10158-019-0231-0