Nematodes Ancylostoma Caninum Research Articles

Helminths of free-ranging dogs and cats in an urban natural reserve in Mexico City and their potential risk as zoonotic agents.

In the Reserva Ecológica del Pedregal of San Ángel, located in the south of Mexico City, Mexico, free-roaming dogs and cats coexist with 148 bird, 33 of mammal, 23 of reptile and seven amphibian species, that represent a remnant of the original fauna of the Mexican Plateau. The negative impact that dogs and cats have on local fauna is unobjectionable, however, the role that these introduced vertebrates play as potential transmitters of infectious diseases for native fauna and humans, is much less understood. Information about parasitic infections in native and introduced animals in this location is scarce. In order to ameliorate this lack of information, the objective of this study is to characterize the helminth fauna of the free-ranging dogs and cats of the ecological reserve. Between 2018 and 2023, 36 Felis silvestris catus and 7 Canis lupus familiaris were studied from the helminthological perspective. Endoparasites were obtained from the digestive tract and were identified to the species level using morphological and molecular evidence. Hosts were parasitized by eight species of helminths: in cats the cestodes Hydatigera taeniaeformis, Mesocestoides sp., Taenia rileyi and the nematode Toxocara cati were recorded, while in dogs, the cestode Taenia pisiformis and the nematodes Ancylostoma caninum, and Uncinaria stenocephala were found. The only species shared between cats and dogs was the cestode Dipylidium caninum. These free-ranging animals act as definitive hosts of 5 species known to have zoonotic potential; their presence in the area may generate a public and animal health problem if programs of dog and cat population control are not continued.

Cloning, sequencing and phylogenetic analysis of the small GTPase gene cdc-42 from Ancylostoma caninum

CDC-42 is a member of the Rho GTPase subfamily that is involved in many signaling pathways, including mitosis, cell polarity, cell migration and cytoskeleton remodeling. Here, we present the first characterization of a full-length cDNA encoding the small GTPase cdc-42, designated as Accdc-42, isolated from the parasitic nematode Ancylostoma caninum. The encoded protein contains 191 amino acid residues with a predicted molecular weight of 21 kDa and displays a high level of identity with the Rho-family GTPase protein CDC-42. Phylogenetic analysis revealed that Accdc-42 was most closely related to Caenorhabditis briggsae cdc-42. Comparison with selected sequences from the free-living nematode Caenorhabditis elegans, Drosophila melanogaster, Xenopus laevis, Danio rerio, Mus musculus and human genomes showed that Accdc-42 is highly conserved. AcCDC-42 demonstrates the highest identity to CDC-42 from C. briggsae (94.2%), and it also exhibits 91.6% identity to CDC-42 from C. elegans and 91.1% from Brugia malayi. Additionally, the transcript of Accdc-42 was analyzed during the different developmental stages of the worm. Accdc-42 was expressed in the L1/L2 larvae, L3 larvae and female and male adults of A. caninum.

High prevalence of intestinal infections and ectoparasites in dogs, Minas Gerais State (southeast Brazil)

In the present study, 155 dogs euthanized by the Zoonotic Disease Unit of Uberlândia in Minas Gerais State (Southeast Brazil) were autopsied. Ectoparasites were collected, and the intestinal content of dogs was systematically examined for the presence of helminthic parasites. In total, we isolated 5,155 metazoan parasites of eight species (three intestinal helminth species, five ectoparasite species). The cestode Dipylidium caninum was present in 57 dogs (36.8 %), the nematodes Ancylostoma caninum in 30 (19.4 %) and Toxocara canis in 24 (15.5 %), respectively. Among the ectoparasites, 139 (89.7 %) dogs were infested with Rhipicephalus sanguineus, 115 (74.2 %) with Ctenocephalides felis, 5 (3.2 %) with Tunga penetrans and one specimen (0.7 %) with Amblyomma cajennense, while myiasis was found in one dog (0.7 %). In logistic regression analysis, young age (adjusted odds ratio 5.74; 95 % confidence interval 1.18-27.85) and male sex (3.60; 1.24-10.40) were significantly associated with toxocariasis, and crossbreed dogs (8.20; 1.52-44.31), with dipylidiasis. Male (2.23; 1.12-4.43) and crossbreed dogs (5.17; 1.17-22.83) had also a significant higher number of concomitant parasitoses. Spatial distribution of dogs by neighbourhood identified high-risk areas. Our systematic study shows that dogs in Uberlândia carry a high number of parasites which may cause zoonotic diseases in humans; therefore, further specific evidence-based intervention measures are needed.

A faecal analysis of helminth infections in wild and captive wolves, Canis lupus L., in Poland

One hundred and three samples of faeces of reared grey wolves from four locations (Stobnica Park and Zoological Gardens in Bydgoszcz, Wrocław and Cracow) and twenty-six samples of faeces from two free-roaming packs of grey wolf (Canis lupus L.) in Piła (Forest Divisions: Borne Sulinowo, Czarnobór, Jastrowo) and Zielona Góra (Forest Divisions: Torzym, Krosno Odrzańskie) were collected between 2005 and 2007. Helminth eggs were detected in 78.6% of faecal samples of reared grey wolves and in 88.4% of those of free-roaming wolves. The trematode Alaria alata (80.1%) and nematodes Eucoleus aerophilus (23.1%) and Spirocerca lupi (11.5%) were only detected from wild packs of wolves and the nematodes Ancylostoma caninum (35.9%), Trichuris vulpis (15.5%) and Toxocara canis (3.9%) were only detected from reared wolves. Differences were observed in the prevalence and composition of helminth fauna between reared and wild grey wolves and our results are compared with those from studies within Poland and elsewhere in Europe.

Immunogenicity of the recombinant ASP1r protein of A. caninum in a murine model

Background: Ancylostomiasis is a disease produced by the intestinal hematofhagous nematode Ancylostoma caninum. This parasite has as major excretion/secretion protein ASP1, which has a molecular weight of 42KDa and is encoded by a gene of 1016pb.

Identification of an anticoagulant peptide that inhibits both fXIa and fVIIa/tissue factor from the blood-feeding nematode Ancylostoma caninum

Factor VIIa-tissue factor complex (fVIIa/TF) and factor XIa (fXIa) play important roles in the initiation and amplification of coagulation, respectively. They may be good targets for the development of novel anticoagulants to treat and prevent thromboembolic disease. In this study, we cloned, expressed and identified a novel anticoagulant peptide, AcaNAP10, from the blood-feeding nematode Ancylostoma caninum. AcaNAP10 showed potent anticoagulant activity and doubled the activated partial thromboplastin and prothrombin times at estimated concentrations of 92.9 nM and 28.8 nM, respectively. AcaNAP10 demonstrated distinct mechanisms of action compared with known anticoagulants. It inhibited fXIa and fVIIa/TF with IC 50 values of 25.76 ± 1.06 nM and 123.9 ± 1.71 nM, respectively. This is the first report on an anticoagulant that can inhibit both fXIa and fVIIa/TF. This anticoagulant peptide may be an alternative molecule for the development of novel anticoagulants.

Helminth parasites of the wolfCanis lupusfrom Latvia

Thirty-four wolves were collected between 2003 and 2008 from throughout Latvia and examined for helminths. A total of 17 helminth species were recorded: the trematode Alaria alata (85.3%); the cestodes Diphyllobothrium latum (2.9%), Echinococcus granulosus (2.9%), Echinococcus multilocularis (5.9%), Mesocestoides lineatus (5.9%), Taenia crassiceps (8.8%), Taenia hydatigena (41.2%), Taenia (ovis) krabbei (8.8%), Taenia multiceps (47.1%), Taenia pisiformis (20.6%), Taenia polyacantha (11.8%), Taenia spp. (8.8%); and the nematodes Ancylostoma caninum (2.9%), Crenosoma vulpis (9.1%), Eucoleus aerophilus (36.4%), Pearsonema plica (41.4%), Trichinella spp. (69.7%), Toxocara canis (5.8%), and Uncinaria stenocephala (41.2%). Alaria alata presented the highest mean intensity (403.8). All animals were infected with at least one species of parasite, while the maximum recorded in one specimen was eight. No differences in the intensity or prevalence of any helminth species were found among the host based on age and gender, except for T. multiceps which was more prevalent in adults than in juveniles.

Intermolecular Interactions and Characterization of the Novel Factor Xa Exosite Involved in Macromolecular Recognition and Inhibition: Crystal Structure of Human Gla-domainless Factor Xa Complexed with the Anticoagulant Protein NAPc2 from the Hematophagous Nematode Ancylostoma caninum

NAPc2, an anticoagulant protein from the hematophagous nematode Ancylostoma caninum evaluated in phase-II/IIa clinical trials, inhibits the extrinsic blood coagulation pathway by a two step mechanism, initially interacting with the hitherto uncharacterized factor Xa exosite involved in macromolecular recognition and subsequently inhibiting factor VIIa ( K i = 8.4 pM) of the factor VIIa/tissue factor complex. NAPc2 is highly flexible, becoming partially ordered and undergoing significant structural changes in the C terminus upon binding to the factor Xa exosite. In the crystal structure of the ternary factor Xa/NAPc2/selectide complex, the binding interface consists of an intermolecular antiparallel β-sheet formed by the segment of the polypeptide chain consisting of residues 74–80 of NAPc2 with the residues 86–93 of factor Xa that is additional maintained by contacts between the short helical segment (residues 67–73) and a turn (residues 26–29) of NAPc2 with the short C-terminal helix of factor Xa (residues 233–243). This exosite is physiologically highly relevant for the recognition and inhibition of factor X/Xa by macromolecular substrates and provides a structural motif for the development of a new class of inhibitors for the treatment of deep vein thrombosis and angioplasty.

The structure and evolution of Penelope in the virilis species group of Drosophila: an ancient lineage of retroelements.

The Penelope element is the key element responsible for mobilization of other transposable elements in the course of hybrid dysgenesis in Drosophila virilis. Penelope has an unusually complex, highly variable organization in all studied species of the virlis group. Thc BRIDGE1 element from the fish Fugu rubripes is homologous to Penelope, and database searches detected additional homologous sequences among Expressed Sequence Tags from the flatworm Schistosoma mansonii and the nematode Ancylostoma caninum. Phylogenetic analysis shows that the reverse transcriptase of the Penelope group does not belong to any of the characterized major retroelement lineages, but apparently represents a novel branch of non-LTR retroelements. Sequence profile analysis results in the prediction that the C-terminal domain of the Penelope polyprotein is an active endonuclease related to intron-encoded endonucleases and the bacterial repair endonuclease UvrC, which could function as an integrase. No retroelements containing a predicted endonuclease of this family have been described previously. Phylogenetic analysis of Penelope copies isolated from several species of the virilis group reveals two subfamilies of Penelope elements, one of which includes full-length copies whose nucleotide sequences are almost identical, whereas the other one consists of highly diverged defective copies. Phylogenetic analysis of Penelope suggests both vertical transmission of the element and probable horizontal transfers. These findings support the notion that Penelope invasions occurred repeatedly in the evolution of the virilis group.

Inherent flexibility in a potent inhibitor of blood coagulation, recombinant nematode anticoagulant protein c2.

Nematode anticoagulant proteins (NAPs) from the hematophagous nematode Ancylostoma caninum inhibit blood coagulation with picomolar inhibition constants, and have been targeted as novel pharmaceutical agents. NAP5 and NAP6 inhibit factor Xa by binding to its active site, whereas NAPc2 binds to factor Xa at a different, as yet unidentified, site and the resultant binary complex inhibits the tissue factor-factor VIIa complex. We have undertaken NMR studies of NAPc2, including the calculation of a solution structure, and found that the protein is folded, with five disulfide bonds, but is extremely flexible, especially in the acidic loop. The Halpha secondary shifts and 3JHNHalpha coupling constants indicate the presence of some beta structure and a short helix, but the intervening loops are highly conformationally heterogeneous. Heteronuclear NOE measurements showed the presence of large amplitude motions on a subnanosecond timescale at the N-terminus and C-terminus and in the substrate-binding loop, indicating that the conformational heterogeneity observed in the NMR structures is due to flexibility of the polypeptide chain in these regions. Flexibility may well be an important factor in the physiological function of NAPc2, because it must interact with other proteins in the inhibition of blood coagulation. We suggest that this inhibitor is likely to become structured on binding to factor Xa, because the inhibition of the tissue factor-factor VIIa complex requires both NAPc2 and factor Xa.

Developmental Arrest and Pregnancy-Induced Transmammary Transmission of Ancylostoma caninum Larvae in the Murine Model

Pregnancy is associated with reactivation of latent infections of many protozoal and helminthic parasites. To facilitate in vivo studies on the process of transmammary transmission of hookworm infection to nursing newborns, we established an experimental model of infection of BALB/c mice with infective larvae of the canine nematode Ancylostoma caninum. To establish latency with a significant reservoir of tissue larvae and achieve acceptable pregnancy success rates, mice were subcutaneously infected at day 5 postimpregnation; similar larval distribution profiles were observed at the end of the gestational period for bred compared to correspondingly infected unbred animals. No larvae were detected in fetuses or neonatal pups. Significant numbers of larvae were not detected in mammary tissue during the periparturient or postpartum lactational periods although about 8% of a dam's reservoir of tissue larvae was transferred to her nursing pups; this suggests that larvae reaching the mammary glands are rapidly transmitted through the milk sinuses, as was documented by histopathological analyses. Comparison of BALB/c with C57BL/6 mice that typically display divergent immune responses to infection showed no difference in tissue larval burden or in numbers transferred to pups. A hypothesis for the molecular mechanism of larval reactivation and transmission is discussed.