DOCSLIB.ORG

Heterogeneity in Transmission Parameters of Hookworm Infection Within the Baseline Data from the TUMIKIA Study in Kenya James E

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Heterogeneity in Transmission Parameters of Hookworm Infection Within the Baseline Data from the TUMIKIA Study in Kenya James E Truscott et al. Parasites Vectors (2019) 12:442 https://doi.org/10.1186/s13071-019-3686-2 Parasites & Vectors RESEARCH Open Access Heterogeneity in transmission parameters of hookworm infection within the baseline data from the TUMIKIA study in Kenya James E. Truscott1,2,3*, Alison K. Ower1,2, Marleen Werkman1,2,3, Katherine Halliday3,4, William E. Oswald3,4, Paul M. Gichuki5, Carlos Mcharo5, Simon Brooker6, Sammy M. Njenga5, Charles Mwandariwo5, Judd L. Walson1,3,7, Rachel Pullan4 and Roy Anderson1,2,3 Abstract Background: As many countries with endemic soil-transmitted helminth (STH) burdens achieve high coverage levels of mass drug administration (MDA) to treat school-aged and pre-school-aged children, understanding the detailed efects of MDA on the epidemiology of STH infections is desirable in formulating future policies for morbidity and/or transmission control. Prevalence and mean intensity of infection are characterized by heterogeneity across a region, leading to uncertainty in the impact of MDA strategies. In this paper, we analyze this heterogeneity in terms of factors that govern the transmission dynamics of the parasite in the host population. Results: Using data from the TUMIKIA study in Kenya (cluster STH prevalence range at baseline: 0–63%), we esti- mated these parameters and their variability across 120 population clusters in the study region, using a simple para- site transmission model and Gibbs-sampling Monte Carlo Markov chain techniques. We observed great heterogeneity in R0 values, with estimates ranging from 1.23 to 3.27, while k-values (which vary inversely with the degree of parasite aggregation within the human host population) range from 0.007 to 0.29 in a positive association with increasing prevalence. The main fnding of this study is the increasing trend for greater parasite aggregation as prevalence declines to low levels, refected in the low values of the negative binomial parameter k in clusters with low hookworm prevalence. Localized climatic and socioeconomic factors are investigated as potential drivers of these observed epidemiological patterns. Conclusions: Our results show that lower prevalence is associated with higher degrees of aggregation and hence prevalence alone is not a good indicator of transmission intensity. As a consequence, approaches to MDA and moni- toring and evaluation of community infection status may need to be adapted as transmission elimination is aimed for by targeted treatment approaches. Keywords: Soil-transmitted helminths, Heterogeneity, Model ftting, Parasite aggregation Background (Ascaris lumbricoides) and hookworm (Ancylostoma Soil-transmitted helminths (STH) are the most preva- duodenale and Necator americanus), but the majority of lent of the neglected tropical diseases (NTD), infect- the global health burden results from hookworm species, ing up to 1.5 billion people world-wide. Te STH group which are estimated to account for the loss of approxi- comprises whipworm (Trichuris trichiura), roundworm mately 5.2 million disability-adjusted life years [1]. Te current WHO approach is to achieve control of STH *Correspondence: [email protected] infections through programmes of mass drug adminis- 1 London Centre for Neglected Tropical Disease Research, Department tration (MDA) targeted at school-aged and pre-school- of Infectious Disease Epidemiology, Imperial College London, St Mary’s aged children as well as other high-risk groups [2]. Campus, London W2 1PG, UK Full list of author information is available at the end of the article Recently, however, there has been an increased interest © The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creat iveco mmons .org/licen ses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Truscott et al. Parasites Vectors (2019) 12:442 Page 2 of 13 in the possibility of interrupting transmission through a parasite populations cannot persist due to low mating short period of intensifed community-wide MDA. Sev- success. Treshold values are strongly dependent on the eral recent and ongoing studies are currently testing this degree of parasite aggregation and transmission intensity, hypothesis [3, 4]. as measured by R0 [16, 17]. For soil-transmitted helminths, both prevalence and Based on the models that describe parasite transmis- intensity are key epidemiological measures of community sion, we can associate observed prevalence and intensity infection status for policy and programmatic decision- levels with the parameters that quantify the transmission making. Within WHO guidelines, prevalence determines cycle of the parasite and the diagnostic techniques used whether treatment is given, at what frequency and for to measure the epidemiological quantities of prevalence how long [2, 5]. Severity of infection, as measured by and intensity of infection. By ftting the model to data on the faecal egg count of infected individuals, is used as a prevalence and intensity of infection to all clusters inde- proxy for worm load and infection-induced morbidity. pendently, we can examine the variability in parameter Te latter is a key element in cost efectiveness calcula- values to see how much can be explained by cluster-level tions [6–8]. However, within larger geographical regions, environmental and demographic correlates. Importantly, a great deal of heterogeneity is observed in the meas- a model ftted to data in this way can then be applied to ured prevalence and intensity of STH infection. Tis may directly investigating how prevalence and intensity in the refect variations in environmental conditions such as region will evolve with time in individual clusters under temperature and humidity, diferences in social mixing diferent regimes of MDA treatment. or hygiene practices within the human host population, or the impacts of difering past MDA coverages [9, 10]. Methods Spatial heterogeneity in prevalence and intensity makes Epidemiological data it hard to predict how a region will respond to a control Te TUMIKIA trial was initiated in 2015 with the aim of or elimination intervention based on MDA or WASH evaluating school versus community-based deworming (water, sanitation and hygiene) improvements. As most on STH transmission in Kwale county, coastal Kenya [3, countries enter a stage of high MDA coverage, at least in 18]. Te study comprises three arms; namely, a control pre-school-aged and school-aged children, understand- group of annual school-based de-worming, a group with ing the efects of MDA on STH infections is a prereq- annual community-wide deworming, and a third group uisite for the evaluation of the possible interruption of with community-wide deworming biannually. Te data parasite transmission at the community level. used in this analysis comes from the baseline survey. Tis study analyses the spatial variability in hookworm In the decade prior to the baseline survey of the study, prevalence and intensity in a collection of contiguous this region received several rounds of lymphatic flariasis communities taken from the baseline of a cluster-ran- (LF) treatment (in 2003, 2005, 2008 and 2011), employ- domized trial conducted in coastal Kenya to evaluate ing diethylcarbamazine citrate (DEC, 6 mg/kg) plus treatment strategies for the soil transmitted helminths albendazole (400 mg), through the National Programme [3]. We seek to characterize the variability in the preva- for Elimination of Lymphatic Filariasis (NPELF) [19]. lence and intensity in terms of key epidemiological Furthermore, from 2012 through 2014 annual school- parameters, such as the basic reproduction number (R0) based deworming with albendazole (400 mg) occurred and the degree of parasite aggregation (as measured through a programme, run by the Kenyan Ministries of inversely by the negative binomial parameter k) in the Health and Education, to deworm all school-aged and human host population. Te analysis is based on ftting a pre-school-aged children living in high STH risk areas disease transmission mathematical model to the baseline [20]. However, there is strong anecdotal evidence that the data. Tis approach ensures that the resulting param- efective coverage levels for the prior rounds of treatment eter values refect the disease transmission processes are signifcantly lower than those ofcially recorded (per- found in endemic (or approximately endemic) parasite haps averaging 30% in reality). populations. Te baseline survey was conducted in 120 contigu- Our method puts constraints on possible parameter ous study clusters, each comprising approximately 1000 fts that are not present in purely statistical approaches to households or 5000 individuals. We used the cross-sec- analyses [11–14]. Mathematical models of macroparasite tional hookworm data from the study baseline, deter- infection predict ‘breakpoints’ in transmission created by mined using duplicate Kato-Katz slide readings from a the dioecious nature of helminths and the concomitant single stool sample. Sample sizes from clusters ranged need for both male and female parasites to be in the same from 110 to 294 individuals of all ages, selected
Load more

Recommended publications
  • Hookworm (Ancylostomiasis)
    Hookworm (ancylostomiasis) Hookworm (ancylostomiasis) rev Jan 2018 BASIC EPIDEMIOLOGY Infectious Agent Hookworm is a soil transmitted helminth. Human infections are caused by the nematode parasites Necator americanus and Ancylostoma duodenale. Transmission Transmission primarily occurs via direct contact with fecal contaminated soil. Soil becomes contaminated with eggs shed in the feces of an individual infected with hookworm. The eggs must incubate in the soil for several days before they become infectious and are able to be transmitted to another person. Oral transmission can sometimes occur from consuming improperly washed food grown or exposed to fecal contaminated soil. Transmission can also occur (rarely) between a mother and her fetus/infant via infected placental or mammary tissue. Incubation Period Eggs must incubate in the soil for 5-10 days before they mature into infectious filariform larvae that can penetrate the skin. Within the first 10 days following penetration of the skin filariform larvae will migrate to the lungs and occasionally cause respiratory symptoms. Three to five weeks after skin penetration the larvae will migrate to the intestinal tract where they will mature into an adult worm. Adult worms may live in the intestine for 1-5 years depending on the species. Communicability Human to human transmission of hookworm does NOT occur because part of the worm’s life cycle must be completed in soil before becoming infectious. However, vertical transmission of dormant filariform larvae can occur between a mother and neonate via contaminated breast milk. These dormant filariform larvae can remain within in a host for months to years. Soil contamination is perpetuated by fecal contamination from infected individuals who can shed eggs in feces for several years after infection.
    [Show full text]
  • Lecture 5: Emerging Parasitic Helminths Part 2: Tissue Nematodes
    Readings-Nematodes • Ch. 11 (pp. 290, 291-93, 295 [box 11.1], 304 [box 11.2]) • Lecture 5: Emerging Parasitic Ch.14 (p. 375, 367 [table 14.1]) Helminths part 2: Tissue Nematodes Matt Tucker, M.S., MSPH [email protected] HSC4933 Emerging Infectious Diseases HSC4933. Emerging Infectious Diseases 2 Monsters Inside Me Learning Objectives • Toxocariasis, larva migrans (Toxocara canis, dog hookworm): • Understand how visceral larval migrans, cutaneous larval migrans, and ocular larval migrans can occur Background: • Know basic attributes of tissue nematodes and be able to distinguish http://animal.discovery.com/invertebrates/monsters-inside- these nematodes from each other and also from other types of me/toxocariasis-toxocara-roundworm/ nematodes • Understand life cycles of tissue nematodes, noting similarities and Videos: http://animal.discovery.com/videos/monsters-inside- significant difference me-toxocariasis.html • Know infective stages, various hosts involved in a particular cycle • Be familiar with diagnostic criteria, epidemiology, pathogenicity, http://animal.discovery.com/videos/monsters-inside-me- &treatment toxocara-parasite.html • Identify locations in world where certain parasites exist • Note drugs (always available) that are used to treat parasites • Describe factors of tissue nematodes that can make them emerging infectious diseases • Be familiar with Dracunculiasis and status of eradication HSC4933. Emerging Infectious Diseases 3 HSC4933. Emerging Infectious Diseases 4 Lecture 5: On the Menu Problems with other hookworms • Cutaneous larva migrans or Visceral Tissue Nematodes larva migrans • Hookworms of other animals • Cutaneous Larva Migrans frequently fail to penetrate the human dermis (and beyond). • Visceral Larva Migrans – Ancylostoma braziliense (most common- in Gulf Coast and tropics), • Gnathostoma spp. Ancylostoma caninum, Ancylostoma “creeping eruption” ceylanicum, • Trichinella spiralis • They migrate through the epidermis leaving typical tracks • Dracunculus medinensis • Eosinophilic enteritis-emerging problem in Australia HSC4933.
    [Show full text]
  • Studies Show That Fecal Dx Antigen Tests Allow for Earlier Detection of More Intestinal Parasites
    Research update Studies show that Fecal Dx antigen tests allow for earlier detection of more intestinal parasites Antigen detection is commonly used today to diagnose Results heartworm and Giardia infections, and now it is available for In the 1,156 field fecal samples for the roundworm and hookworm additional parasites. IDEXX Reference Laboratories, as a leader study and the 1,000 field fecal samples for the whipworm study, in pet healthcare innovation, has developed immunoassays for egg-positive roundworm, hookworm, and whipworm results were the detection of hookworm, roundworm, and whipworm antigens noted in 23, 13, and 27 samples, respectively. In contrast, 26, 19, in feces of dogs and cats. These antigens are secreted from the and 35 samples were antigen positive for roundworm, hookworm, adult worm and are not present in their eggs, which allows for and whipworm. The T. canis ELISA detected T. cati coproantigen in detection of prepatent stages as well as the ability to overcome the feline samples. Fecal antigens detected more infections than did challenges of intermittent egg laying. Earlier detection during the fecal flotation. prepatent period will also reduce the frequency of environmental contamination with potentially infectious eggs. Roundworm Hookworm Whipworm Two recent papers describing the performance of the Fecal Dx™ antigen tests, enzyme-linked immunosorbent assays (ELISAs) Fecal flotation 23 13 27 developed by IDEXX for coproantigen detection of Trichuris vulpis, positive Ancylostoma caninum and Toxocara canis in dogs and Toxocara cati in cats, are summarized below. Fecal Dx antigen 26 19 35 • Enzyme-linked immunosorbent assay for coproantigen detection test positive of Trichuris vulpis in dogs1 • Enzyme-linked immunosorbent assays for coproantigen Table 1.
    [Show full text]
  • Performance of Two Serodiagnostic Tests for Loiasis in A
    Performance of two serodiagnostic tests for loiasis in a Non-Endemic area Federico Gobbi, Dora Buonfrate, Michel Boussinesq, Cédric Chesnais, Sébastien Pion, Ronaldo Silva, Lucia Moro, Paola Rodari, Francesca Tamarozzi, Marco Biamonte, et al. To cite this version: Federico Gobbi, Dora Buonfrate, Michel Boussinesq, Cédric Chesnais, Sébastien Pion, et al.. Perfor- mance of two serodiagnostic tests for loiasis in a Non-Endemic area. PLoS Neglected Tropical Dis- eases, Public Library of Science, 2020, 14 (5), pp.e0008187. 10.1371/journal.pntd.0008187. inserm- 02911633 HAL Id: inserm-02911633 https://www.hal.inserm.fr/inserm-02911633 Submitted on 4 Aug 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. PLOS NEGLECTED TROPICAL DISEASES RESEARCH ARTICLE Performance of two serodiagnostic tests for loiasis in a Non-Endemic area 1 1 2 2 Federico GobbiID *, Dora Buonfrate , Michel Boussinesq , Cedric B. Chesnais , 2 1 1 1 3 Sebastien D. Pion , Ronaldo Silva , Lucia Moro , Paola RodariID , Francesca Tamarozzi , Marco Biamonte4, Zeno Bisoffi1,5 1 IRCCS Sacro
    [Show full text]
  • Environmental Characteristics Around the Household and Their Association with Hookworm Infection in Rural Communities from Bahir Dar, Amhara Region, Ethiopia
    RESEARCH ARTICLE Environmental characteristics around the household and their association with hookworm infection in rural communities from Bahir Dar, Amhara Region, Ethiopia Melaku Anegagrie1,2☯, SofõÂa Lanfri3,4☯, Aranzazu Amor Aramendia1,2, Carlos 3,5 2 2 4 MatõÂas ScavuzzoID , Zaida HerradorID , AgustõÂn BenitoID , Maria Victoria PeriagoID * 1 FundacioÂn Mundo Sano, Madrid, Spain, 2 National Centre for Tropical Medicine, Institute of Health Carlos III, Madrid, Spain, 3 Instituto de Altos Estudios Espaciales Mario Gulich, ComisioÂn Nacional de Actividades Espaciales, Universidad Nacional de CoÂrdoba, CoÂrdoba, Argentina, 4 FundacioÂn Mundo Sano, Buenos a1111111111 Aires, Argentina, 5 Consejo Nacional de Investigaciones CientõÂficas y TeÂcnicas (CONICET), Buenos Aires, a1111111111 Argentina a1111111111 ☯ These authors contributed equally to this work. a1111111111 * [email protected] a1111111111 Abstract OPEN ACCESS Soil-Transmitted Helminths (STH) are highly prevalent Neglected Tropical Disease in Ethio- pia, an estimated 26 million are infected. Geographic Information Systems and Remote Citation: Anegagrie M, Lanfri S, Aramendia AA, Scavuzzo CM, Herrador Z, Benito A, et al. (2021) Sensing (RS) technologies assist data mapping and analysis, and the prediction of the spa- Environmental characteristics around the tial distribution of infection in relation to environmental variables. The influence of socioeco- household and their association with hookworm nomic, environmental and soil characteristics on hookworm infection at the individual and infection in rural communities from Bahir Dar, household level is explored in order to identify spatial patterns of infection in rural villages Amhara Region, Ethiopia. PLoS Negl Trop Dis 15(6): e0009466. https://doi.org/10.1371/journal. from Zenzelema (Amhara region). Inhabitants greater than 5 years old were recruited in pntd.0009466 order to assess the presence of STH.
    [Show full text]
  • Ancylostoma Ceylanicum
    Wei et al. Parasites & Vectors (2016) 9:518 DOI 10.1186/s13071-016-1795-8 RESEARCH Open Access The hookworm Ancylostoma ceylanicum intestinal transcriptome provides a platform for selecting drug and vaccine candidates Junfei Wei1, Ashish Damania1, Xin Gao2, Zhuyun Liu1, Rojelio Mejia1, Makedonka Mitreva2,3, Ulrich Strych1, Maria Elena Bottazzi1,4, Peter J. Hotez1,4 and Bin Zhan1* Abstract Background: The intestine of hookworms contains enzymes and proteins involved in the blood-feeding process of the parasite and is therefore a promising source of possible vaccine antigens. One such antigen, the hemoglobin-digesting intestinal aspartic protease known as Na-APR-1 from the human hookworm Necator americanus, is currently a lead candidate antigen in clinical trials, as is Na-GST-1 a heme-detoxifying glutathione S-transferase. Methods: In order to discover additional hookworm vaccine antigens, messenger RNA was obtained from the intestine of male hookworms, Ancylostoma ceylanicum, maintained in hamsters. RNA-seq was performed using Illumina high-throughput sequencing technology. The genes expressed in the hookworm intestine were compared with those expressed in the whole worm and those genes overexpressed in the parasite intestine transcriptome were further analyzed. Results: Among the lead transcripts identified were genes encoding for proteolytic enzymes including an A. ceylanicum APR-1, but the most common proteases were cysteine-, serine-, and metallo-proteases. Also in abundance were specific transporters of key breakdown metabolites, including amino acids, glucose, lipids, ions and water; detoxifying and heme-binding glutathione S-transferases; a family of cysteine-rich/antigen 5/pathogenesis-related 1 proteins (CAP) previously found in high abundance in parasitic nematodes; C-type lectins; and heat shock proteins.
    [Show full text]
  • Prevalence, Risk Factors, and Geographical Distribution of Zoonotic Pathogens Carried by Peri-Urban Wild Dogs
    Prevalence, risk factors, and geographical distribution of zoonotic pathogens carried by peri-urban wild dogs Lana Claire Harriott BSc (Hons I) A thesis submitted for the degree of Doctor of Philosophy at The University of Queensland in 2017 School of Veterinary Science Abstract Established wildlife populations within peri-urban and urban environments provide an opportunity for the spread of zoonotic pathogens to and from human-associated environments. Wild dogs, including dingoes (Canis lupus dingo), feral domestic dogs (Canis lupus familiaris), and their cross breeds (hybrids) are common across the Australian mainland, and hybrid populations are particularly frequent within peri-urban environments. Previous studies have shown that wild dogs carry zoonotic pathogens of public health significance, however, data relating to peri-urban wild dogs has been limited to a few studies with a small geographical range and / or small sample size. To address the potential public health implications of peri-urban wild dogs, information regarding pathogen diversity, prevalence, risk factors and geographical distribution are required. To investigate the diversity and prevalence of zoonotic pathogens in peri-urban wild dogs, a cross sectional survey was undertaken. Utilising council management programs and private trappers, 201 wild dogs were collected for necropsy. Analysis of faecal and blood samples indicated that helminth parasites were common, detected within 79.6 5.4 % of wild dogs tested, however bacterial pathogens were much less prevalent. Echinococcus granulosus was the most prevalent parasite detected by necropsy, (prevalence 50.7 6.9 %). Hookworms were found to comprise the second most common pathogen of zoonotic significance with an overall prevalence of 28.8% ( 7.1%).
    [Show full text]
  • PARASITIC WORMS FOUND in STOMACH WHILE DOING UPPER GASTRO- IJCRR Section: Healthcare INTESTINAL ENDOSCOPY and STUDY Sci
    Research Article PARASITIC WORMS FOUND IN STOMACH WHILE DOING UPPER GASTRO- IJCRR Section: Healthcare INTESTINAL ENDOSCOPY AND STUDY Sci. Journal Impact Factor 4.016 OF THE DIFFERENCES BETWEEN ADULT HOOKWORMS AND LARVA OF ANISAKIS SIMPLEX INFECTING STOMACH Govindarajalu Ganesan Associate Professor, Department of General Surgery, Aarupadai Veedu Medical College and Hospital, Puducherry- 607402, India. ABSTRACT Objective: To diagnose parasitic worms found in stomach while doing upper gastro-intestinal endoscopy in our patients. There have not been many studies in India which discuss about the presence and the type of parasitic worms present in stomach while doing upper gastro-intestinal endoscopy. Hence this present study was carried out to study about the presence and the type of parasitic worms present in stomach while doing upper gastro-intestinal endoscopy in our institute. Methods: A study of 707 patients who had undergone upper gastro-intestinal endoscopy for a period of two years and eight months from May 2009 to December 2011 was carried out in our institute. In each of the 707 patients, the stomach was carefully examined to find out the presence of parasitic worms. The results were found as given below. Results: Of the 707 patients, one patient was found to have hookworm in stomach instead of its usual site in duodenum while doing upper gastro-intestinal endoscopy. Conclusion: Hence upper gastro-intestinal endoscopy is a very useful investigation to diagnose parasitic infection like hook- worm infection of stomach . Hence it is extremely important to carefully look for the presence of parasitic worms like hookworms in stomach while doing upper gastro-intestinal endoscopy.
    [Show full text]
  • Ancylostomiasis (Hookworm Disease)
    EAZWV Transmissible Disease Fact Sheet Sheet No. 104 ANCYLOSTOMIASIS (HOOKWORM DISEASE) ANIMAL TRANS- CLINICAL FATAL TREATMENT PREVENTION GROUP MISSION SIGNS DISEASE ? & CONTROL AFFECTED Percutaneous- rarely In houses Pongidae, ly Larva migrans Mebendazol Cercopitheci (in man also symptoms, dae, perorally via dyspnea, in zoos Cebidae. breast milk). diarrhea. Fact sheet compiled by Last update Manfred Brack, formerly German Primate Center, 22.11..2008 Göttingen/Germany. Susceptible animal groups Gorilla gorilla,Pan troglodytes, Hylobates sp.,Papio sp.,Macaca mulatta,Cercopithecus mona : A.duodenale ; Cebus capucinus, Ateles sp.,Erythrocebus patas, Cercopithecus mona : Necator americanus. Causative organism Ancylostoma duodenale, Necator americanus (Nematoda, Strongylina: Ancylostomatidae). Zoonotic potential Yes. Distribution A.duodenale : world-wide, predominantly in tropical/subtropical S.E.Asia and America; N.americanus : tropical and subtropical rain forests. Transmission Percutaneously by filariform ( 3 rd stage) larvae. Incubation period Clinical symptoms Pot belly syndrome, apnea, cutaneous larva migrans, persistent diarrhea, in man also anemia. Post mortem findings Not reported in nonhuman primates. Diagnosis Ovodiagnosis ( cave: ancylostomatid eggs may be confused with the very similar oesophagostomid eggs!), followed by fecoculture of filariform larvae (Harada-Mori technique). Material required for laboratory analysis Relevant diagnostic laboratories Treatment Mebendazole (2 x 15 mg / kg or 10 x 3 mg / kg). Ivermectin is almost
    [Show full text]
  • Anisakiosis and Pseudoterranovosis
    National Wildlife Health Center Anisakiosis and Pseudoterranovosis Circular 1393 U.S. Department of the Interior U.S. Geological Survey 1 2 3 4 5 6 7 8 Cover: 1. Common seal, by Andreas Trepte, CC BY-SA 2.5; 2. Herring catch, National Oceanic and Atmospheric Administration; 3. Larval Pseudoterranova sp. in muscle of an American plaice, by Dr. Lena Measures; 4. Salmon sashimi, by Blu3d, Lilyu, GFDL CC BY-SA3.0; 5. Beluga whale, by Jofre Ferrer, CC BY-NC-ND 2.0; 6. Dolphin, National Aeronautics and Space Administration; 7. Squid, National Oceanic and Atmospheric Administration; 8. Krill, by Oystein Paulsen, CC BY-SA 3.0. Anisakiosis and Pseudoterranovosis By Lena N. Measures Edited by Rachel C. Abbott and Charles van Riper, III USGS National Wildlife Health Center Circular 1393 U.S. Department of the Interior U.S. Geological Survey ii U.S. Department of the Interior SALLY JEWELL, Secretary U.S. Geological Survey Suzette M. Kimball, Acting Director U.S. Geological Survey, Reston, Virginia: 2014 For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit http://www.usgs.gov or call 1–888–ASK–USGS For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit http://store.usgs.gov Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text.
    [Show full text]
  • Helminth and Arthropod Parasites of Grizzly and Black Bears in Montana and Adjacent Areas
    Third International Conference on Bears Paper 45 Helminth and Arthropod Parasites of Grizzly and Black Bears in Montana and Adjacent Areas DAVID E. WORLEY J. CARL FOX JOHN B. WINTERS RICHARDH. JACOBSON Veterinary Research Laboratory, Montana State University, Bozeman, Montana 59715 and KENNETH R. GREER (Montana Department of Fish and Game). 608 South Grand, Bozeman, Montana 59715 INTRODUCTION Parasites of free-ranging grizzly and black bears in North America have been investigated periodically since the early part of the present century. The emphasis in many of these studies was on the role of bears as potential sources of parasites transmissible to man such as the trichina worm, Trichinella spiralis (Maynard & Pauls 1962, Harbottle et al. 1971,Wand & Lyman 1972) and the broad fish tapeworm (Vergeer 1930. Rush 1932, Skinker 1931,1932). Other work has been confined primarily to taxonomic surveys or descriptive studies of parasitism in wild bears (Horstman 1949, Olsen 1968, Choquette et al. 1969). Little of the literature has been concerned with the potential influences of parasitism on the health of bear populations in the environment. The present study was designed with this objective in mind. MATERIALSAND METHODS Entire carcasses or selected organs or tissues from grizzly and black bears were obtained from a variety of sources, including National Park Service personnel in Yellowstone and Glacier National Parks, Fish and Wildlife service predator control agents, Montana Fish and Game Department biolo- gists, and hunters. The area surveyed included approximately the western third of Montana and Yellowstone National Park. Most bears were necropsied within 48 hours after death except for the examination for T.
    [Show full text]
  • Developing Vaccines to Combat Hookworm Infection and Intestinal Schistosomiasis
    REVIEWS Developing vaccines to combat hookworm infection and intestinal schistosomiasis Peter J. Hotez*, Jeffrey M. Bethony*‡, David J. Diemert*‡, Mark Pearson§ and Alex Loukas§ Abstract | Hookworm infection and schistosomiasis rank among the most important health problems in developing countries. Both cause anaemia and malnutrition, and schistosomiasis also results in substantial intestinal, liver and genitourinary pathology. In sub-Saharan Africa and Brazil, co-infections with the hookworm, Necator americanus, and the intestinal schistosome, Schistosoma mansoni, are common. The development of vaccines for these infections could substantially reduce the global disability associated with these helminthiases. New genomic, proteomic, immunological and X-ray crystallographic data have led to the discovery of several promising candidate vaccine antigens. Here, we describe recent progress in this field and the rationale for vaccine development. In terms of their global health impact on children and that combat hookworm and schistosomiasis, with an pregnant women, as well as on adults engaged in subsist- emphasis on disease caused by Necator americanus, the ence farming, human hookworm infection (known as major hookworm of humans, and Schistosoma mansoni, ‘hookworm’) and schistosomiasis are two of the most the primary cause of intestinal schistosomiasis. common and important human infections1,2. Together, their disease burdens exceed those of all other neglected Global distribution and pathobiology tropical diseases3–6. They also trap the world’s poorest Hookworms are roundworm parasites that belong to people in poverty because of their deleterious effects the phylum Nematoda. They share phylogenetic simi- on child development and economic productivity7–9. larities with the free-living nematode Caenorhabditis Until recently, the importance of these conditions as elegans and with the parasitic nematodes Nippostrongylus global health and economic problems had been under- brasiliensis and Heligmosomoides polygyrus, which are appreciated.
    [Show full text]