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Stocker T, Ward MP, Šlapeta J. Nationwide USA re-analysis of amplicon metabarcoding targeting β-tubulin isoform-1 reveals absence of benzimidazole resistant SNPs in Ancylostoma braziliense, Ancylostoma tubaeforme and Uncinaria stenocephala. Vet Parasitol 2024; 327:110118. [PMID: 38278035 DOI: 10.1016/j.vetpar.2024.110118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/13/2024] [Accepted: 01/14/2024] [Indexed: 01/28/2024]
Abstract
Nationwide sampling by Venkatesan and colleagues (2023) described the resistance status of the canine hookworm, Ancylostoma caninum, to benzimidazoles across the USA via β-tubulin isotype-1 amplicon metabarcoding. In this study, we aimed to use the existing public amplicon metabarcoding data and mine it for the presence of β-tubulin isotype-1 sequences that belong to hookworm species other than A. caninum. Through bioinformatics analysis we assigned species to A. caninum, Ancylostoma braziliense, Ancylostoma tubaeforme and Uncinaria stenocephala. All non-A. caninum sequences contained only the benzimidazole susceptible residues of β-tubulin isotype-1. Using two β-tubulin isotype-1 metabarcoding sequence data (assay targeting 134 and 167 codons, and assay targeting 198 and 200 codons), 2.0% (6/307) and 2.9% (9/310) individual samples had hookworms other than A. caninum (A. braziliense n = 5, A. tubaeforme n = 4 and U. stenocephala n = 2), respectively. We identified one sample containing A. braziliense in each of the Northeastern region and Midwestern region, and in three samples from the Southern region. Presence of A. tubaeforme in dog faeces is considered as pseudoparasitism. There were no statistically significant regional differences for the distribution of each species, for either of the two assays independently or combined (χ2 tests, P > 0.05). Our work demonstrates the utility of the amplicon metabarcoding for the identification of species through antemortem assays, thus resolving the dilemma of assigning hookworm species based on either post-mortem or egg sizes for the identification of hookworms.
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Affiliation(s)
- Thomas Stocker
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, New South Wales 2006, Australia
| | - Michael P Ward
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, New South Wales 2006, Australia
| | - Jan Šlapeta
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, New South Wales 2006, Australia; The University of Sydney Institute for Infectious Diseases, New South Wales 2006, Australia.
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Ng'etich AI, Amoah ID, Bux F, Kumari S. Anthelmintic resistance in soil-transmitted helminths: One-Health considerations. Parasitol Res 2023; 123:62. [PMID: 38114766 PMCID: PMC10730643 DOI: 10.1007/s00436-023-08088-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 12/05/2023] [Indexed: 12/21/2023]
Abstract
The One-Health approach recognizes the intricate connection between human, animal, and environmental health, and that cooperative effort from various professionals provides comprehensive awareness and potential solutions for issues relating to the health of people, animals, and the environment. This approach has increasingly gained appeal as the standard strategy for tackling emerging infectious diseases, most of which are zoonoses. Treatment with anthelmintics (AHs) without a doubt minimizes the severe consequences of soil-transmitted helminths (STHs); however, evidence of anthelmintic resistance (AR) development to different helminths of practically every animal species and the distinct groups of AHs is overwhelming globally. In this regard, the correlation between the application of anthelmintic drugs in both human and animal populations and the consequent development of anthelmintic resistance in STHs within the context of a One-Health framework is explored. This review provides an overview of the major human and animal STHs, treatment of the STHs, AR development and drug-related factors contributing towards AR, One-Health and STHs, and an outline of some One-Health strategies that may be used in combating AR.
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Affiliation(s)
- Annette Imali Ng'etich
- Institute for Water and Wastewater Technology, Durban University of Technology (DUT), Durban, South Africa
| | - Isaac Dennis Amoah
- Institute for Water and Wastewater Technology, Durban University of Technology (DUT), Durban, South Africa
- Department of Environmental Science, University of Arizona, Tucson, AZ, USA
| | - Faizal Bux
- Institute for Water and Wastewater Technology, Durban University of Technology (DUT), Durban, South Africa
| | - Sheena Kumari
- Institute for Water and Wastewater Technology, Durban University of Technology (DUT), Durban, South Africa.
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Sumboh JG, Agyenkwa-Mawuli K, Schwinger E, Donkor IO, Akorli JEB, Dwomoh D, Ashong Y, Osabutey D, Ababio FO, Koram KA, Humphries D, Cappello M, Kwofie SK, Wilson MD. Investigating Environmental Determinants of Soil-Transmitted Helminths Transmission using GPS Tracking and Metagenomics Technologies. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.07.17.23292808. [PMID: 37503260 PMCID: PMC10371187 DOI: 10.1101/2023.07.17.23292808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Background The Global Health community aims to eliminate soil-transmitted helminth (STH) infections by 2030. Current preventive methods such as Mass Drug Administration, WASH practices, and health education needs to be complimented to halt transmission. We tracked the movement of hookworm-infected and non-infected persons and investigated soil factors in the places they frequented within an endemic community to further understand the role of human movement and sources of infections. Methods 59 positive and negative participants wore GPS tracking devices for 10 consecutive days and their movement data captured in real time. The data was overlaid on the community map to determine where each group differentially spent most of their time. Soil samples were collected from these identified sites and other communal places. Physical and chemical properties were determined for each sample using standard methods and helminth eggs cultured into larvae using the Baermann technique. Bivariate and multivariate analyses were used to determine associations between larvae counts and soil factors. Helminth species were identified with metagenomic sequencing and their distributions mapped to sampling sites in the community. Results The study found that there was no significant difference in the average larvae counts in soil between sites assessed by infected and non-infected participants (P=0.59). However, soil factors, such as pH, carbon and sandy-loamy texture were associated with high larvae counts (P<0.001) while nitrogen and clay content were associated with low counts(P<0.001). The dominant helminth species identified were Panagrolaimus superbus (an anhydrobiotic helminth), Parastrongyloides trichosuri (a parasite of small mammals), Trichuris trichuria (whipworm), and Ancylostoma caninum (dog hookworm). Notably, no Necator americanus was identified in any soil sample. Conclusion This study provides important insights into the association between soil factors and soil-transmitted helminths. These findings contribute to our understanding of STH epidemiology and support evidence-based decision-making for elimination strategies.
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Affiliation(s)
- Jeffrey Gabriel Sumboh
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana. Legon, Accra, Ghana
| | - Kwasi Agyenkwa-Mawuli
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana. Legon, Accra, Ghana
| | - Eyram Schwinger
- Department of Mathematics, University of Ghana. Legon, Accra, Ghana
| | - Irene Owusu Donkor
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, University of Ghana. Legon, Accra, Ghana
| | - Jewelna E. B. Akorli
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana. Legon, Accra, Ghana
| | - Duah Dwomoh
- Department of Biostatistics, School of Public Health, University of Ghana. Legon, Accra, Ghana
| | - Yvonne Ashong
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana. Legon, Accra, Ghana
| | - Dickson Osabutey
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana. Legon, Accra, Ghana
| | - Felix Owusu Ababio
- Soil Research Institute, Council for Scientific and Industrial Research, Accra, Ghana
| | - Kwadwo Ansah Koram
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, University of Ghana. Legon, Accra, Ghana
| | - Debbie Humphries
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, United States of America
| | - Michael Cappello
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, United States of America
| | - Samuel K. Kwofie
- School of Biomedical Engineering, Faculty of Engineering, University of Ghana. Legon, Accra, Ghana
| | - Michael D. Wilson
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana. Legon, Accra, Ghana
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Ballard AM, Laramee N, Haardörfer R, Freeman MC, Levy K, Caruso BA. Measurement in the study of human exposure to animal feces: A systematic review and audit. Int J Hyg Environ Health 2023; 249:114146. [PMID: 36868140 PMCID: PMC10044406 DOI: 10.1016/j.ijheh.2023.114146] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 01/31/2023] [Accepted: 02/23/2023] [Indexed: 03/05/2023]
Abstract
BACKGROUND Human exposure to animal feces is increasingly recognized as an important transmission route of enteric pathogens. Yet, there are no consistent or standardized approaches to measurement of this exposure, limiting assessment of the human health effects and scope of the issue. OBJECTIVE To inform and improve approaches to the measurement of human exposure to animal feces, we audited existing measurement in low- and middle-income countries. METHODS We systematically searched peer-reviewed and gray literature databases for studies with quantitative measures of human exposure to animal feces and we classified measures in two ways. First, using a novel conceptual model, we categorized measures into three 'Exposure Components' identified a priori (i.e., Animal, Environmental, Human Behavioral); one additional Component (Evidence of Exposure) inductively emerged. Second, using the exposure science conceptual framework, we determined where measures fell along the source-to-outcome continuum. RESULTS We identified 1,428 measures across 184 included studies. Although studies overwhelmingly included more than one single-item measure, the majority only captured one Exposure Component. For example, many studies used several single-item measures to capture the same attribute for different animals, all of which were classified as the same Component. Most measures captured information about the source (e.g. animal presence) and contaminant (e.g. animal-sourced pathogens), which are most distal from exposure on the source-to-outcome continuum. DISCUSSION We found that measurement of human exposure to animal feces is diverse and largely distal from exposure. To facilitate better assessment of the human health effects of exposure and scope of the issue, rigorous and consistent measures are needed. We recommend a list of key factors from the Animal, Environmental, and Human Behavioral Exposure Components to measure. We also propose using the exposure science conceptual framework to identify proximal measurement approaches.
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Affiliation(s)
- April M Ballard
- Gangarosa Department of Environmental Health, Emory University Rollins School of Public Health, Atlanta, GA, USA.
| | - Nicholas Laramee
- Hubert Department of Global Health, Emory University Rollins School of Public Health, Atlanta, GA, USA
| | - Regine Haardörfer
- Department of Behavioral, Social and Health Education Sciences, Emory University Rollins School of Public Health, Atlanta, GA, USA
| | - Matthew C Freeman
- Gangarosa Department of Environmental Health, Emory University Rollins School of Public Health, Atlanta, GA, USA
| | - Karen Levy
- Department of Environmental and Occupational Health Sciences, University of Washington School of Public Health, Seattle, WA, USA
| | - Bethany A Caruso
- Gangarosa Department of Environmental Health, Emory University Rollins School of Public Health, Atlanta, GA, USA; Hubert Department of Global Health, Emory University Rollins School of Public Health, Atlanta, GA, USA
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Intestinal Helminth Infections in Ghanaian Children from the Ashanti Region between 2007 and 2008—A Retrospective Cross-Sectional Real-Time PCR-Based Assessment. Trop Med Infect Dis 2022; 7:tropicalmed7110374. [DOI: 10.3390/tropicalmed7110374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 10/18/2022] [Accepted: 11/12/2022] [Indexed: 11/16/2022] Open
Abstract
In spite of ongoing eradication programs, helminth infections are still a medical issue in Ghana. For follow-up assessments on the decline of regional helminth infections, historic baseline prevalence values obtained with standardized diagnostic procedures can be helpful. In this retrospective cross-sectional study, real-time PCR targeting the nematodes Ancylostoma spp. (ITS2), Ascaris lumbricoides (ITS1), Enterobius vermicularis (ITS1), Necator americanus (ITS2), Strongyloides stercoralis (18S rRNA) and Trichuris trichiura (18S rRNA), the trematodes Schistosoma spp. (ITS2) as well as the cestodes Hymenolepis nana (ITS1), Taenia saginata (ITS1) and Taenia solium (ITS1) was applied with 2046 DNA eluates from stool samples of Ghanaian children from the Ashanti region collected between 2007 and 2008 in order to retrospectively define prevalence values. The overall prevalence was low with 3.8% (n = 77) and only 0.1% (n = 2) double infections with helminths were recorded. The three most frequently detected enteric helminth species comprised 2% S. stercoralis (n = 41), 0.8% H. nana (n = 16), and 0.7% N. americanus (n = 14), while only sporadic infection events were recorded for other helminth species comprising 0.1% E. vermicularis (n = 2), 0.1% Schistosoma spp. (n = 2), 0.1% T. saginata (n = 1) and 0.1% T. trichiura (n = 1). A. lumbricoides, Ancylostoma spp. and T. solium were not detected at all. In conclusion, the retrospective assessment suggests a low prevalence of enteric helminth infections in Ghanaian children from the Ashanti Region within the assessment period between 2007 and 2008.
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Morphologic Characterization of Strongylida Larvae from Human and Swine Coprocultures in Rural Communities in the State of Piauí, Northeastern Brazil. J Trop Med 2022; 2022:7251922. [PMID: 36051189 PMCID: PMC9427283 DOI: 10.1155/2022/7251922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 06/15/2022] [Indexed: 11/17/2022] Open
Abstract
Some helminth species belonging to the order Strongylida are parasites of the digestive tract of vertebrates, including man and domestic animals. In humans, infections with Oesophagostomum spp. and Trichostrongylus spp. may be misdiagnosed as hookworm disease on parasitological stool examination, mainly in regions where these infections are coendemic, since eggs released in hosts’ feces are morphologically similar. This study presents the morphologic characterization of Strongylida larvae recovered from humans and pigs living in close proximity, exploring putative zoonotic cycles. One hundred three humans and 27 pigs were included in low-resource rural communities in the state of Piauí, northeastern Brazil. Strongylida eggs were present in 12 (11.7%) humans and 23 (85.2%) pigs through conventional parasitological examination. Strongylida-positive fecal samples were submitted to coprocultures using the Harada–Mori technique. All 22 larvae obtained from human feces were classified as hookworms (Ancylostomatidae). From a total of 37 larvae obtained from swine, 23 (62.3%) were classified as Oesophagostomum, 6 (16.2%) were Hyostrongylus, and 4 (10.8%) were Trichostrongylus. Four larvae (10.8%) obtained from pigs were classified as Strongyloides. The morphological study of filariform larvae obtained in coprocultures is a useful and inexpensive tool in the screening of intestinal helminthiasis in a One Health approach.
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Seroprevalence of toxocariasis among allergic patients in Kuwait and its association with eosinophilia. Parasite Epidemiol Control 2022; 18:e00260. [PMID: 35818473 PMCID: PMC9270249 DOI: 10.1016/j.parepi.2022.e00260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 06/21/2022] [Accepted: 06/27/2022] [Indexed: 11/23/2022] Open
Abstract
Toxocariasis is a worldwide helminthic infection which is transmitted from infected dogs and cats and has been associated with peripheral blood eosinophilia. The Centers for Disease Control and Prevention (CDC) placed toxocariasis among the top 6 parasitic diseases in the USA which are prioritized for public health action. To our knowledge, there are no reports on human toxocariasis in Kuwait or in the other Gulf Cooperation Council (GCC) countries. This study aims at investigating the seroprevalence of toxocariasis among allergic patients in Kuwait and its association with eosinophilia, age, gender, nationality, and history of direct contact with dogs or cats. From September to December 2021, the laboratory records of allergic patients referred to Al-Rashed Allergy Hospital, Kuwait were reviewed and a total of 400 serum samples were selected: 200 samples from patients with normal eosinophil count (< 500 cells/μl) and 200 samples from patients with eosinophilia (> 500 cells/μl). The sera were screened for anti-Toxocara canis IgG antibodies via antibody enzyme-linked immunosorbent assay (Ab-ELISA). The seropositive patients were asked about their history of direct contact with dogs or cats. Statistical analyses were performed using Microsoft Excel® Analysis ToolPak software. Toxocariasis seropositivity was detected in 10 out of 400 (2.5%) allergic patients. Five patients had eosinophilia while 5 had normal eosinophil count. There was no difference in mean age or gender between Toxocara-seropositive and seronegative patients (p > 0.05). The seroprevalence rate was lower-than-expected among Kuwaiti patients (2/307, 0.7%) in comparison with non-Kuwaiti patients (8/57, 14.0%) (χ2 = 33.603, df = 1, p < 0.001) who originated from endemic South/Southeast Asian countries. Seven out of 8 (87.5%) seropositive patients had a history of direct contact with cats, dogs, or both. The seroprevalence rate of toxocariasis among allergic patients in Kuwait was 2.5%. Raising awareness and early deworming treatment/prophylaxis for juvenile dogs and cats remain crucial for toxocariasis prevention.
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Liu G, Wang S, Liang W, Hornok S, Zhao S, Tan W, Liu Z, Gu X, Wang Y. Arthrostoma leucurus sp. n. (Nematoda: Ancylostomatidae), A New Hookworm Species Isolated from Asian Badger in China. Acta Parasitol 2022; 67:1447-1454. [PMID: 35870100 PMCID: PMC9399214 DOI: 10.1007/s11686-022-00587-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 06/15/2022] [Indexed: 11/30/2022]
Abstract
Purpose To date, ten validated Arthrostoma species were reported. Here, a new hookworm species was found from Asian badger (Meles leucurus). Methods Nineteen hookworms (9 males and 10 females) were collected from the small intestine of two Asian badgers in Xinjiang Uygur Autonomous Region, northwestern China. The hookworms were morphologically examined according to key taxonomic characters, such as anterior extremity direction, structures of oral opening (cutting plates or teeth), vulva location, buccal capsule anatomy (integrated or formed by articulating plates), the length of spicule and gubernaculum, number of plates of buccal capsule, and presence or absence of vulvar papillae.
Results The hookworm species from Asian badger, here named as Arthrostoma leucurus sp. n., was different from the previously described ten Arthrostoma species. The phylogenetic tree based on the cox1 gene showed that Arthrostoma leucurus sp. n. formed a separate clade, as a sister group to Ancylostoma and Uncinaria species. Conclusion Arthrostoma leucurus sp. n., the eleven validated Arthrostoma species, was identified from Asian badger in China. Supplementary Information The online version contains supplementary material available at 10.1007/s11686-022-00587-5.
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Affiliation(s)
- Gang Liu
- School of Medicine, Shihezi University, Shihezi, 832002 Xinjiang Uygur Autonomous Region People’s Republic of China
- College of Animal Science and Technology, Shihezi University, Shihezi, 832002 Xinjiang Uygur Autonomous Region People’s Republic of China
- NHC Key Laboratory of Prevention and Treatment of Central Asia High Incidence Diseases, First Affiliated Hospital, School of Medicine, Shihezi University, Shihezi City, Xinjiang Uygur Autonomous Region People’s Republic of China
| | - Shiyi Wang
- School of Medicine, Shihezi University, Shihezi, 832002 Xinjiang Uygur Autonomous Region People’s Republic of China
- NHC Key Laboratory of Prevention and Treatment of Central Asia High Incidence Diseases, First Affiliated Hospital, School of Medicine, Shihezi University, Shihezi City, Xinjiang Uygur Autonomous Region People’s Republic of China
| | - Weihua Liang
- School of Medicine, Shihezi University, Shihezi, 832002 Xinjiang Uygur Autonomous Region People’s Republic of China
- NHC Key Laboratory of Prevention and Treatment of Central Asia High Incidence Diseases, First Affiliated Hospital, School of Medicine, Shihezi University, Shihezi City, Xinjiang Uygur Autonomous Region People’s Republic of China
| | - Sándor Hornok
- Department of Parasitology and Zoology, University of Veterinary Medicine, Budapest, 1078 Hungary
| | - Shanshan Zhao
- School of Medicine, Shihezi University, Shihezi, 832002 Xinjiang Uygur Autonomous Region People’s Republic of China
- NHC Key Laboratory of Prevention and Treatment of Central Asia High Incidence Diseases, First Affiliated Hospital, School of Medicine, Shihezi University, Shihezi City, Xinjiang Uygur Autonomous Region People’s Republic of China
| | - Wenbo Tan
- School of Medicine, Shihezi University, Shihezi, 832002 Xinjiang Uygur Autonomous Region People’s Republic of China
- NHC Key Laboratory of Prevention and Treatment of Central Asia High Incidence Diseases, First Affiliated Hospital, School of Medicine, Shihezi University, Shihezi City, Xinjiang Uygur Autonomous Region People’s Republic of China
| | - Zhiqiang Liu
- Institute of Veterinary Medicine, Xinjiang Academy of Animal Science, Ürümqi, Xinjiang Uygur Autonomous Region People’s Republic of China
| | - Xinli Gu
- College of Animal Science and Technology, Shihezi University, Shihezi, 832002 Xinjiang Uygur Autonomous Region People’s Republic of China
| | - Yuanzhi Wang
- School of Medicine, Shihezi University, Shihezi, 832002 Xinjiang Uygur Autonomous Region People’s Republic of China
- NHC Key Laboratory of Prevention and Treatment of Central Asia High Incidence Diseases, First Affiliated Hospital, School of Medicine, Shihezi University, Shihezi City, Xinjiang Uygur Autonomous Region People’s Republic of China
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Morley NJ. Vertebrates as uninfected disseminators of helminth eggs and larvae. ADVANCES IN PARASITOLOGY 2022; 115:45-170. [PMID: 35249663 DOI: 10.1016/bs.apar.2021.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The passive dispersal of non-mobile organisms by vertebrates (zoochory) is a common mechanism used to explain their often widespread distribution. Transport occurs either internally via the vertebrate digestive tract (endozoochory), or externally be adhering to skin, feathers or fur (ectozoochory), and its success is due to both physiological and ecological factors associated with the disseminating 'hosting' animal. Helminth eggs and larvae are generally non-mobile stages that are largely dependent on the movement of another animal, typically a host, for geographical dissemination. Studies on the zoochory of helminths by vertebrates are extensive and particularly long-standing, stretching back to the 19th century, although this literature is often overlooked when considering the biogeography of parasites. This review assesses the potential of helminths to be dispersed passively by zoochory examining evidence from both laboratory and field studies. The physiological dynamics of the vertebrate intestines and skin surface as hostile environments, as well as the characteristics of eggs and larvae which may facilitate successful transport are evaluated. The various mechanisms of helminth endo- and ectozoochory are presented and the likelihood of long-distance dispersal determined. It is concluded that zoochory is a potentially important means of disseminating parasites.
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Affiliation(s)
- Neil J Morley
- School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, United Kingdom.
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