Helminthiasis - wikipedia Helminthiasis Jump to : navigation , search This article is about the infection . For the organisms , see Helminths . Helminthiasis Synonyms helminthosis , helminthiases , helminth infection Ascaris worms ( one type of helminth ) in the small bowel of an infected person in South Africa ( X-ray image with barium as contrast medium ) Pronunciation / ˌhɛlminˈθaɪəsis / Classification and external resources Specialty infectious disease ICD - 10 B83. 9 ICD - 9 - CM 128.9 DiseasesDB 28826 MeSH D006373 ( edit on Wikidata ) Helminthiasis ( plural helminthiases ) , also known as worm infection , is any macroparasitic disease of humans and other animals in which a part of the body is infected with parasitic worms , known as helminths . There are numerous species of these parasites , which are broadly classified into tapeworms , flukes , and roundworms . They often live in the gastrointestinal tract of their hosts , but they may also burrow into other organs , where they induce physiological damage . Soil - transmitted helminthiasis and schistosomiasis are the most important helminthiases , and are among the neglected tropical diseases . This group of helmianthiases have been targeted under the joint action of the world 's leading pharmaceutical companies and non-governmental organizations through a project launched in 2012 called the London Declaration on Neglected Tropical Diseases , which aims to control or eradicate certain neglected tropical diseases by 2020 . Helminthiasis has been found to result in poor birth outcome , poor cognitive development , poor school and work performance , poor socioeconomic development , and poverty . Chronic illness , malnutrition , and anemia are further examples of secondary effects . Soil - transmitted helminthiases are responsible for parasitic infections in as much as a quarter of the human population worldwide . One well - known example of soil - transmitted helminthiases is ascariasis . Contents ( hide ) 1 Signs and symptoms 1.1 Mass and volume 1.2 Immunological response 2 Secondary effects 2.1 Immune changes 2.2 Chronic illness 2.3 Malnutrition 2.4 Anemia 2.5 Cognitive changes 3 Helminths types causing infections 3.1 Roundworm infection ( nematodiasis ) 3.2 Tapeworm infection ( cestodiasis ) 3.3 Trematode infection ( trematodiasis ) 3.4 Acanthocephala infection 4 Transmission 5 Diagnosis 6 Prevention 7 Treatment 7.1 Medications 7.2 Mass deworming 7.3 Surgery 8 Epidemiology 8.1 Neglected tropical diseases 8.2 Prevalence 8.3 Variations within communities 8.4 Disability - adjusted life years 8.5 Deaths 9 See also 10 References 11 External links Signs and symptoms ( edit ) Example clinical photo : Guinea worm infection ( dracunculiasis ) , worm coming out of the foot of an infected person . Ascaris infection : Antimesenteric splitting of the outer layers of the bowel wall due to a large amount of ascaris ( South Africa ) The signs and symptoms of helminthiasis depend on a number of factors including : the site of the infestation within the body ; the type of worm involved ; the number of worms and their volume ; the type of damage the infesting worms cause ; and , the immunological response of the body . Where the burden of parasites in the body is light , there may be no symptoms . Certain worms may cause particular constellations of symptoms . For instance , taeniasis can lead to seizures due to neurocysticercosis . Mass and volume ( edit ) In extreme cases of intestinal infestation , the mass and volume of the worms may cause the outer layers of the intestinal wall , such as the muscular layer , to tear . This may lead to peritonitis , volvulus , and gangrene of the intestine . Immunological response ( edit ) As pathogens in the body , helminths induce an immune response . Immune - mediated inflammatory changes occur in the skin , lung , liver , intestine , central nervous system , and eyes . Signs of the body 's immune response may include eosinophilia , edema , and arthritis . An example of the immune response is the hypersensitivity reaction that may lead to anaphylaxis . Another example is the migration of Ascaris larvae through the bronchi of the lungs causing asthma . Secondary effects ( edit ) Immune changes ( edit ) See also : Effects of parasitic worms on the immune system Micrograph of cut section of human appendix showing a pin worm . In humans , T helper cells and eosinophils respond to helminth infestation . Inflammation leads to encapsulation of egg deposits throughout the body . Helminths excrete into the intestine toxic substances after they feed . These substances then enter the circulatory and lymphatic systems of the host body . Chronic immune responses to helminthiasis may lead to increased susceptibility to other infections such as tuberculosis , HIV , and malaria . There is conflicting information about whether deworming reduces HIV progression and viral load and increases CD4 counts in antiretroviral naive and experienced individuals . Chronic illness ( edit ) Chronic helminthiasis may cause severe morbidity . Helminthiasis has been found to result in poor birth outcome , poor cognitive development , poor school and work performance , decreased productivity , poor socioeconomic development , and poverty . Malnutrition ( edit ) Helminthiasis may cause chronic illness through malnutrition including vitamin deficiencies , stunted growth , anemia , and protein - energy malnutrition . Worms compete directly with their hosts for nutrients , but the magnitude of this effect is likely minimal as the nutritional requirements of worms is relatively small . In pigs and humans , Ascaris has been linked to lactose intolerance and vitamin A , amino acid , and fat malabsorption . Impaired nutrient uptake may result from direct damage to the intestinal mucosal wall or from more subtle changes such as chemical imbalances and changes in gut flora . Alternatively , the worms ' release of protease inhibitors to defend against the body 's digestive processes may impair the breakdown of other nutrients . In addition , worm induced diarrhoea may shorten gut transit time , thus reducing absorption of nutrients . Malnutrition due to worms can give rise to anorexia . A study of 459 children in Zanzibar revealed spontaneous increases in appetite after deworming . Anorexia might be a result of the body 's immune response and the stress of combating infection . Specifically , some of the cytokines released in the immune response to worm infestation have been linked to anorexia in animals . Anemia ( edit ) Helminths may cause iron - deficiency anemia . This is most severe in heavy hookworm infections , as Necator americanus and Ancylostoma duodenale feed directly on the blood of their hosts . Although the daily consumption of an individual worm ( 0.02 -- 0.07 ml and 0.14 -- 0.26 ml respectively ) is small , the collective consumption under heavy infection can be clinically significantly . Intestinal whipworm may also cause anemia . Anemia has also been associated with reduced stamina for physical labor , a decline in the ability to learn new information , and apathy , irritability , and fatigue . A study of the effect of deworming and iron supplementation in 47 students from the Democratic Republic of the Congo found that the intervention improved cognitive function . Another study found that in 159 Jamaican schoolchildren , deworming led to better auditory short - term memory and scanning and retrieval of long - term memory over a period of nine - weeks . Cognitive changes ( edit ) Malnutrition due to helminths may affect cognitive function leading to low educational performance , decreased concentration and difficulty with abstract cognitive tasks . Iron deficiency in infants and preschoolers is associated with `` lower scores ... on tests of mental and motor development ... ( as well as ) increased fearfulness , inattentiveness , and decreased social responsiveness '' . Studies in the Philippines and Indonesia found a significant correlation between helminthiasis and decreased memory and fluency . Large parasite burdens , particularly severe hookworm infections , are also associated with absenteeism , under - enrollment , and attrition in school children . Helminths types causing infections ( edit ) Ascaris life cycle : Adult worms in the lumen of the small intestine ( 1 ) . The female produces eggs ( approximately 200,000 per day ) that are excreted with the feces ( 2 ) . Unfertilized eggs are harmless , but fertilized ones are infective after 18 days to several weeks ( 3 ) . Infective eggs are ingested ( 4 ) , enter the gut ( 5 ) , develop into larvae in the intestine , and penetrate the blood vessel to enter lungs , where they develop further ( 6 ) , after 10 to 14 days , penetrate the alveolar walls , ascend the bronchial tree to the throat , and are re-swallowed ( 7 ) . Upon reaching the small intestine , they develop into adult worms ( 8 ) . It takes 2 to 3 months for one complete cycle . Adult worms can live 1 to 2 years . Collage of various helminth eggs , from left to right : Trichosomoides egg , Ascaris lumbricoides with larva hatching , sample of adult roundworms , Hymenolepis nana , Schistosoma mansoni and Toxocara canis with larva hatching Of all the known helminth species , the most important helminths with respect to understanding their transmission pathways , their control , inactivation and enumeration in samples of human excreta from dried feces , faecal sludge , wastewater , and sewage sludge are : soil - transmitted helminths , including Ascaris lumbricoides ( the most common worldwide ) , Trichuris trichiura , Necator americanus , Strongyloides stercoralis and Ancylostoma duodenale Hymenolepis nana Taenia saginata Enterobius Fasciola hepatica Schistosoma mansoni Toxocara canis Toxocara cati Helminthiases are classified as follows ( the disease names end with `` - sis '' and the causative worms are in brackets ) : Roundworm infection ( nematodiasis ) ( edit ) Filariasis ( Wuchereria bancrofti , Brugia malayi infection ) Onchocerciasis ( Onchocerca volvulus infection ) Soil - transmitted helminthiasis -- this includes ascariasis ( Ascaris lumbricoides infection , trichuriasis ( Trichuris infection ) , and hookworm infection ( includes necatoriasis and Ancylostoma duodenale infection ) Trichostrongyliasis ( Trichostrongylus spp . infection ) Dracunculiasis ( guinea worm infection ) Baylisascaris ( raccoon roundworm , may be transmitted to pets livestock and humans ) Tapeworm infection ( cestodiasis ) ( edit ) Echinococcosis ( Echinococcus infection ) Hymenolepiasis ( Hymenolepis infection ) Taeniasis / cysticercosis ( Taenia infection ) Coenurosis ( T. multiceps , T. serialis , T. glomerata , and T. brauni infection ) Trematode infection ( trematodiasis ) ( edit ) Amphistomiasis ( amphistomes infection ) Clonorchiasis ( Clonorchis sinensis infection ) Fascioliasis ( Fasciola infection ) Fasciolopsiasis ( Fasciolopsis buski infection ) Opisthorchiasis ( Opisthorchis infection ) Paragonimiasis ( Paragonimus infection ) Schistosomiasis / bilharziasis ( Schistosoma infection ) Acanthocephala infection ( edit ) Moniliformis infection Transmission ( edit ) Helminths are transmitted to the final host in several ways . The most common infection is through ingestion of contaminated vegetables , drinking water , and raw or undercooked meat . Contaminated food may contain eggs of nematodes such as Ascaris , Enterobius , and Trichuris ; cestodes such as Taenia , Hymenolepis , and Echinococcus ; and treamtodes such as Fasciola . Raw or undercooked meats are the major sources of Taenia ( pork , beef and venison ) , Trichinella ( pork and bear ) , Diphyllobothrium ( fish ) , Clonorchis ( fish ) , and Paragonimus ( crustaceans ) . Schistosomes and nematodes such as hookworms ( Ancylostoma and Necator ) and Strongyloides can penetrate the skin directly . Finally , Wuchereria , Onchocerca , and Dracunculus are transmitted by mosquitoes and flies . In the developing world , the use of contaminated water is a major risk factor for infection . Infection can also take place through the practice of geophagy , which is not uncommon in parts of sub-Saharan Africa . Soil is eaten , for example , by children or pregnant women to counteract a real or perceived deficiency of minerals in their diet . Diagnosis ( edit ) Identification and quantification of helminth eggs at UNAM university in Mexico City , Mexico Specific helminths can be identified through microscopic examination of their eggs ( ova ) found in faecal samples . The number of eggs is measured in units of eggs per gram . However , it does not quantify mixed infections , and in practice , is inaccurate for quantifying the eggs of schistosomes and soil - transmitted helminths . Sophisticated tests such as serological assays , antigen tests , and molecular diagnosis are also available ; however , they are time - consuming , expensive and not always reliable . Prevention ( edit ) Disrupting the cycle of the worm will prevent infestation and re-infestation . Prevention of infection can largely be achieved by addressing the issues of WASH -- water , sanitation and hygiene . The reduction of open defecation is particularly called for , as is stopping the use of human waste as fertilizer . Further preventive measures include adherence to appropriate food hygiene , wearing of shoes , regular deworming of pets , and the proper disposal of their feces . Scientists are also searching for a vaccine against helminths , such as a hookworm vaccine . Treatment ( edit ) Medications ( edit ) Main article : Anthelmintic Broad - spectrum benzimidazoles ( such as albendazole and mebendazole ) are the first line treatment of intestinal roundworm and tapeworm infections . Macrocyclic lactones ( such as ivermectin ) are effective against adult and migrating larval stages of nematodes . Praziquantel is the drug of choice for schistosomiasis , taeniasis , and most types of food - borne trematodiases . Oxamniquine is also widely used in mass deworming programmes . Pyrantel is commonly used for veterinary nematodiasis . Artemisinins and derivatives are proving to be candidates as drugs of choice for trematodiasis . Mass deworming ( edit ) Main article : Mass deworming In regions where helminthiasis is common , mass deworming treatments may be performed , particularly among school - age children , who are a high - risk group . Most of these initiatives are undertaken by the World Health Organization ( WHO ) with positive outcomes in many regions . Deworming programs can improve school attendance by 25 percent . Although deworming improves the health of an individual , outcomes from mass deworming campaigns , such as reduced deaths or increases in cognitive ability , nutritional benefits , physical growth , and performance , are uncertain or not apparent . Surgery ( edit ) Example of ascariasis ( ascaris infection ) - Difficult surgical procedure in South Africa on a gangrenous piece of bowel that had to be cut out ; live ascaris worms are emerging . Piece of intestine , blocked by worms , surgically removed from a 3 - year - old boy in South Africa . If complications of helminthiasis , such as intestinal obstruction occur , emergency surgery may be required . Patients who require non-emergency surgery , for instance for removal of worms from the biliary tree , can be pre-treated with the anthelmintic drug albendazole . Epidemiology ( edit ) Areas with the highest prevalence of helminthiasis are tropical and subtropical areas including sub-Saharan Africa , central and east Asia , and the Americas . Neglected Tropical diseases ( edit ) Some types of helminthiases are classified as neglected tropical diseases . They include : Soil - transmitted helminthiases Roundworm infections such as lymphatic filariasis , dracunculiasis , and onchocerciasis Trematode infections , such as schistosomiasis , and food - borne trematodiases , including fascioliasis , clonorchiasis , opisthorchiasis , and paragonimiasis Tapeworm infections such as cysticercosis , taeniasis , and echinococcosis Prevalence ( edit ) The soil - transmitted helminths ( A. lumbricoides , T. trichiura , N. americanus , A. duodenale ) , schistosomes , and filarial worms collectively infect more than a quarter of the human population worldwide at any one time , far surpassing HIV and malaria together . Schistosomiasis is the second most prevalent parasitic disease of humans after malaria . In 2014 -- 15 , the WHO estimated that approximately 2 billion people were infected with soil - transmitted helminthiases , 249 million with schistosomiasis , 56 million people with food - borne trematodiasis , 120 million with lymphatic filariasis , 37 million people with onchocerciasis , and 1 million people with echinococcosis . Another source estimated a much higher figure of 3.5 billion infected with one or more soil - transmitted helminths . In 2014 , only 148 people were reported to have dracunculiasis because of a successful eradication campaign for that particular helminth , which is easier to eradicate than other helminths as it is transmitted only by drinking contaminated water . Because of their high mobility and lower standards of hygiene , school - age children are particularly vulnerable to helminthiasis . Most children from developing nations will have at least one infestation . Multi-species infections are very common . Variations within communities ( edit ) Even in areas of high prevalence , the frequency and severity of infection is not uniform within communities or families . A small proportion of community members harbour the majority of worms , and this depends on age . The maximum worm burden is at five to ten years of age , declining rapidly thereafter . Individual predisposition to helminthiasis for people with the same sanitation infrastructure and hygiene behavior is thought to result from differing immunocompetence , nutritional status , and genetic factors . Because individuals are predisposed to a high or a low worm burden , the burden reacquired after successful treatment is proportional to that before treatment . Disability - adjusted life years ( edit ) It is estimated that intestinal nematode infections cause 5 million disability - adjusted life years ( DALYS ) to be lost , of which hookworm infections account for more than 3 million DALYS and ascaris infections more than 1 million . There are also signs of progress : The Global Burden of Disease Study published in 2015 estimates a 46 percent ( 59 percent when age standardised ) reduction in years lived with disability ( YLD ) for the 13 - year time period from 1990 to 2013 for all intestinal / nematode infections , and even a 74 percent ( 80 percent when age standardised ) reduction in YLD from ascariasis . Deaths ( edit ) As many as 135,000 die annually from soil transmitted helminthiasis . The 1990 -- 2013 Global Burden of Disease Study estimated 5,500 direct deaths from schistosomiasis , while more than 200,000 people were estimated in 2013 to die annually from causes related to schistosomiasis . Another 20 million have severe consequences from the disease . It is the most deadly of the neglected tropical diseases . Helminth genera Common name Infections ( million per year ) Direct deaths per year Regions where common Soil transmitted helminthiasis ( STH ) ( classified as neglected tropical disease ) : Ascaris lumbricoides Roundworm 1000 to 1450 807 to 1,121 20,000 Many regions of South - east Asia , Africa , and Central and South America Trichuris trichiura Whipworm 500 604 -- 795 In moist , warm , tropical regions of Asia , Africa , Central and South America , and the Caribbean islands . Ancylostoma duodenale Hookworm 900 to 1300 576 -- 740 ( hookworm in general ) In tropical and subtropical countries ( Sub-Saharan Africa ) Necator americanus Strongyloides stercoralis Hookworm , pinworm 50 to 100 Thousands In moist rainy areas of the tropics and subtropics , in some areas of southern and eastern Europe and of the United States of America All STH together 1500 to 2000 135,000 Tropical and subtropical areas , in particular sub-Saharan Africa , the Americas , China and east Asia . Not transmitted via soil but classified as neglected tropical disease : Schistosoma mansoni Blood fluke All types of Schistosoma together : 160 to 200 ( 210 `` affected '' ) 12,000 150,000 deaths from renal failure 200,000 indirect deaths from `` causes related to '' Schistosomiasis In tropical and subtropical regions Schistosoma haematobium 112 ( in Sub-Saharan Africa alone ) Echinococcus granulosus Developing countries Not transmitted via soil and not classified as neglected tropical disease : Toxocara canis Dog roundworm 50 Many regions of South - east Asia , Africa , and Central and South America Taenia solium Pork tapeworm 50 South America , Southeast Asia , West Africa and East Africa Taenia saginata Beef tapeworm 50 ( all types of Taenia : 40 to 60 ) Hymenolepis nana Dwarf tapeworm 100 Hymenolepis diminuta Rat tapeworm Fasciola hepatica , Fascioloides magna Liver fluke 50 Largely in southern and eastern Asia but also in central and eastern Europe Fasciolopsis buski Giant intestinal fluke Dracunculus medinensis Guinea worm Nowadays negligible thanks to eradication program Formerly widespread in India , west Africa and southern Sudan Trichostrongylus orientalis Roundworm 1 -- 3 ( `` several '' ) Rural communities in Asia Other 100 Worldwide Total ( number of infections ) Approx . 3.5 billion Worldwide See also ( edit ) Kato technique References ( edit ) ^ Jump up to : `` Neglected Tropical Diseases '' . cdc.gov. 6 June 2011 . 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PMID 23813602 . Jump up ^ Kheir M.M. ; Eltoum I.A. ; Saad A.M. ; Ali M.M. ; Baraka O.Z. ; Homeida M.M. ( February 1999 ) . `` Mortality due to schistosomiasis mansoni : a field study in Sudan '' . American Journal of Tropical Medicine and Hygiene. 60 ( 2 ) : 307 -- 10 . PMID 10072156 . Jump up ^ `` Neglected Tropical Diseases '' . cdc.gov. 6 June 2011 . Retrieved 28 November 2014 . ^ Jump up to : `` Parasites -- Soil - transmitted Helminths ( STHs ) '' . Centers for Disease Control and Prevention ( CDC ) . 10 January 2013 . Retrieved 20 December 2014 . ^ Jump up to : Blanca Jiménez ( 2006 ) Irrigation in developing countries using Wastewater , International Review for Environmental Strategies , 6 ( 2 ) : 229 -- 250 . ^ Jump up to : B. Jiménez ( 2007 ) Helminth ova removal from wastewater for agriculture and aquaculture reuse . Water Sciences & Technology , 55 ( 1 -- 2 ) : 485 -- 493 . ^ Jump up to : I. Navarro , B. Jiménez , E. Cifuentes and S. Lucario ( 2009 ) Application of helminth ova infection dose curve to estimate the risks associated with biosolid application on soil , Journal of Water and Health 31 -- 44 . ^ Jump up to : Blanca Jiménez , Inés Navarro ( 2013 ) Wastewater Use in Agriculture : Public Health Considerations . Encyclopedia of Environmental Management . Ed. , Vol. IV , Dr. Sven Erik Jorgensen ( Ed . ) , DOI : 10.1081 / E-EEM - 120046689 Copyright © 2012 by Taylor & Francis . Group , New York , NY , pp 3,512 . ^ Jump up to : UN ( 2003 ) Water for People Water for Life . The United Nations World Water Development Report , UNESCOEd , Barcelona , Spain . ^ Jump up to : WHO ( 1995 ) WHO Model Prescribing Information : Drug Use in Parasitic Diseases . WHO , Geneva , Switzerland . ^ Jump up to : WHO ( 2006 ) . WHO Guidelines for the Safe Use of Wastewater , Excreta and Greywater -- Volume IV : Excreta and greywater use in agriculture . World Health Organization ( WHO ) , Geneva , Switzerland Jump up ^ `` Parasites -- Hookworm '' . Centers for Disease Control and Prevention . Retrieved 20 December 2014 . Jump up ^ Fenwick , A ( Mar 2012 ) . `` The global burden of neglected tropical diseases '' . Public health . 126 ( 3 ) : 233 -- 6 . doi : 10.1016 / j. puhe. 2011.11. 015 . PMID 22325616 . Jump up ^ Lozano , R. ; Naghavi , M. ; Foreman , K. ; Lim , S. ; Shibuya , K. ; Aboyans , V. ; Abraham , J. ; Adair , T. ; et al. ( 15 December 2012 ) . `` Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010 : a systematic analysis for the Global Burden of Disease Study 2010 '' . Lancet . 380 ( 9859 ) : 2095 -- 128 . doi : 10.1016 / S0140 - 6736 ( 12 ) 61728 - 0 . PMID 23245604 . ^ Jump up to : Luke F. Pennington and Michael H. Hsieh ( 2014 ) Immune Response to Parasitic Infections , Bentham e books , Vol 2 , pp. 93 -- 124 , ISBN 978 - 1 - 60805 - 148 - 9 Jump up ^ Elisabetta Profumo , Alessandra Ludovisi , Brigitta Buttari , Maria , Angeles Gomez Morales and Rachele Riganò ( 2014 ) Immune Response to Parasitic Infections , Bentham e books , Bentham Science Publishers , Vol 2 , pp. 69 -- 91 , ISBN 978 - 1 - 60805 - 148 - 9 Jump up ^ Eckert , J. ( 2005 ) . `` Helminths '' . In Kayser , F.H. ; Bienz , K.A. ; Eckert , J. ; Zinkernagel , R.M. Medical Microbiology . Stuttgart : Thieme . pp. 560 -- 562 . ISBN 9781588902450 . Jump up ^ `` Dracunculiasis ( guinea - worm disease ) Fact sheet N ° 359 ( Revised ) '' . World Health Organization . February 2016 . Retrieved 7 February 2016 . External links ( edit ) Information at WHO European Commission Center for Disease Control and Prevention Global Atlas of Helminth Infections Infectious diseases Parasitic disease : helminthiases B65 -- B83 120 -- 129 Flatworm / platyhelminth infection Fluke / trematode ( Trematode infection ) Blood fluke Schistosoma mansoni / japonicum / mekongi / haematobium Schistosomiasis Trichobilharzia regenti Swimmer 's itch Liver fluke Clonorchis sinensis Clonorchiasis Dicrocoelium dendriticum / Dicrocoelium hospes Dicrocoeliasis Fasciola hepatica / gigantica Fasciolosis Opisthorchis viverrini / Opisthorchis felineus Opisthorchiasis Lung fluke Paragonimus westermani / Paragonimus kellicotti Paragonimiasis Intestinal fluke Fasciolopsis buski Fasciolopsiasis Metagonimus yokagawai Metagonimiasis Heterophyes heterophyes Heterophyiasis Cestoda ( Tapeworm infection ) Cyclophyllidea Echinococcus granulosus / Echinococcus multilocularis Echinococcosis Taenia saginata / Taenia asiatica / Taenia solium ( pork ) Taeniasis / Cysticercosis Hymenolepis nana / Hymenolepis diminuta Hymenolepiasis Pseudophyllidea Diphyllobothrium latum Diphyllobothriasis Spirometra erinaceieuropaei Sparganosis Diphyllobothrium mansonoides Sparganosis Roundworm / Nematode infection Secernentea Spiruria Camallanida Dracunculus medinensis Dracunculiasis Spirurida Filarioidea ( Filariasis ) Onchocerca volvulus Onchocerciasis Loa loa Loa loa filariasis Mansonella Mansonelliasis Dirofilaria repens Dirofilaria immitis Dirofilariasis Wuchereria bancrofti / Brugia malayi / Brugia timori Lymphatic filariasis Thelazioidea Gnathostoma spinigerum / Gnathostoma hispidum Gnathostomiasis Thelazia Thelaziasis Spiruroidea Gongylonema Strongylida ( hookworm ) Hookworm infection Ancylostoma duodenale / Ancylostoma braziliense Ancylostomiasis Cutaneous larva migrans Necator americanus Necatoriasis Angiostrongylus cantonensis Angiostrongyliasis Metastrongylus Metastrongylosis Ascaridida Ascaris lumbricoides Ascariasis Anisakis Anisakiasis Toxocara canis / Toxocara cati Visceral larva migrans / Toxocariasis Baylisascaris Dioctophyme renale Dioctophymosis Parascaris equorum Rhabditida Strongyloides stercoralis Strongyloidiasis Trichostrongylus spp . Trichostrongyliasis Halicephalobus gingivalis Oxyurida Enterobius vermicularis Enterobiasis Pinworm Adenophorea Trichinella spiralis Trichinosis Trichuris trichiura ( Trichuriasis * Whipworm ) Capillaria philippinensis Intestinal capillariasis Capillaria hepatica Diseases of poverty Diseases of poverty AIDS Malaria Tuberculosis Measles Pneumonia Diarrheal diseases Neglected diseases Cholera Chagas disease African sleeping sickness Schistosomiasis Dracunculiasis River blindness Leishmaniasis Trachoma Miscellaneous Malnutrition Priority review voucher Biology portal Medicine portal Retrieved from `` https://en.wikipedia.org/w/index.php?title=Helminthiasis&oldid=836695014 '' Categories : Helminthiases Foodborne illnesses Ascaridida Neglected diseases Conditions diagnosed by stool test Intestinal infectious diseases Abdominal pain Sanitation Hidden categories : Infobox medical condition Talk Contents About Wikipedia Azərbaycanca Башҡортса Беларуская Беларуская ( тарашкевіца ) ‎ Català Deutsch Español Euskara Français हिन्दी Íslenska Italiano Қазақша Кыргызча Polski Português Русский Tagalog Українська 11 more Edit links This page was last edited on 16 April 2018 , at 09 : 41 . 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which of the following helmiths feeds on blood
Helminthiasis Synonyms helminthosis , helminthiases , helminth infection Ascaris worms ( one type of helminth ) in the small bowel of an infected person in South Africa ( X-ray image with barium as contrast medium ) Pronunciation / ˌhɛlminˈθaɪəsis / Classification and external resources Specialty infectious disease ICD - 10 B83. 9 ICD - 9 - CM 128.9 DiseasesDB 28826 MeSH D006373 ( edit on Wikidata ) Helminthiasis Synonyms helminthosis , helminthiases , helminth infection Ascaris worms ( one type of helminth ) in the small bowel of an infected person in South Africa ( X-ray image with barium as contrast medium ) Pronunciation / ˌhɛlminˈθaɪəsis / / ˌhɛlminˈθaɪəsis / / ˌhɛlminˈθaɪəsis / Classification and external resources Specialty infectious disease ICD - 10 B83. 9 ICD - 9 - CM 128.9 DiseasesDB 28826 MeSH D006373 ( edit on Wikidata ) Helminthiasis ( plural helminthiases ) , also known as worm infection , is any macroparasitic disease of humans and other animals in which a part of the body is infected with parasitic worms , known as helminths . There are numerous species of these parasites , which are broadly classified into tapeworms , flukes , and roundworms . They often live in the gastrointestinal tract of their hosts , but they may also burrow into other organs , where they induce physiological damage . Soil - transmitted helminthiasis and schistosomiasis are the most important helminthiases , and are among the neglected tropical diseases . This group of helmianthiases have been targeted under the joint action of the world 's leading pharmaceutical companies and non-governmental organizations through a project launched in 2012 called the London Declaration on Neglected Tropical Diseases , which aims to control or eradicate certain neglected tropical diseases by 2020 . Helminthiasis has been found to result in poor birth outcome , poor cognitive development , poor school and work performance , poor socioeconomic development , and poverty . Chronic illness , malnutrition , and anemia are further examples of secondary effects . Soil - transmitted helminthiases are responsible for parasitic infections in as much as a quarter of the human population worldwide . One well - known example of soil - transmitted helminthiases is ascariasis . The signs and symptoms of helminthiasis depend on a number of factors including : the site of the infestation within the body ; the type of worm involved ; the number of worms and their volume ; the type of damage the infesting worms cause ; and , the immunological response of the body . Where the burden of parasites in the body is light , there may be no symptoms . Certain worms may cause particular constellations of symptoms . For instance , taeniasis can lead to seizures due to neurocysticercosis . In extreme cases of intestinal infestation , the mass and volume of the worms may cause the outer layers of the intestinal wall , such as the muscular layer , to tear . This may lead to peritonitis , volvulus , and gangrene of the intestine . As pathogens in the body , helminths induce an immune response . Immune - mediated inflammatory changes occur in the skin , lung , liver , intestine , central nervous system , and eyes . Signs of the body 's immune response may include eosinophilia , edema , and arthritis . An example of the immune response is the hypersensitivity reaction that may lead to anaphylaxis . Another example is the migration of Ascaris larvae through the bronchi of the lungs causing asthma . In humans , T helper cells and eosinophils respond to helminth infestation . Inflammation leads to encapsulation of egg deposits throughout the body . Helminths excrete into the intestine toxic substances after they feed . These substances then enter the circulatory and lymphatic systems of the host body . Chronic immune responses to helminthiasis may lead to increased susceptibility to other infections such as tuberculosis , HIV , and malaria . There is conflicting information about whether deworming reduces HIV progression and viral load and increases CD4 counts in antiretroviral naive and experienced individuals . Chronic helminthiasis may cause severe morbidity . Helminthiasis has been found to result in poor birth outcome , poor cognitive development , poor school and work performance , decreased productivity , poor socioeconomic development , and poverty . Helminthiasis may cause chronic illness through malnutrition including vitamin deficiencies , stunted growth , anemia , and protein - energy malnutrition . Worms compete directly with their hosts for nutrients , but the magnitude of this effect is likely minimal as the nutritional requirements of worms is relatively small . In pigs and humans , Ascaris has been linked to lactose intolerance and vitamin A , amino acid , and fat malabsorption . Impaired nutrient uptake may result from direct damage to the intestinal mucosal wall or from more subtle changes such as chemical imbalances and changes in gut flora . Alternatively , the worms ' release of protease inhibitors to defend against the body 's digestive processes may impair the breakdown of other nutrients . In addition , worm induced diarrhoea may shorten gut transit time , thus reducing absorption of nutrients . Malnutrition due to worms can give rise to anorexia . A study of 459 children in Zanzibar revealed spontaneous increases in appetite after deworming . Anorexia might be a result of the body 's immune response and the stress of combating infection . Specifically , some of the cytokines released in the immune response to worm infestation have been linked to anorexia in animals . Helminths may cause iron - deficiency anemia . This is most severe in heavy hookworm infections , as Necator americanus and Ancylostoma duodenale feed directly on the blood of their hosts . Although the daily consumption of an individual worm ( 0.02 -- 0.07 ml and 0.14 -- 0.26 ml respectively ) is small , the collective consumption under heavy infection can be clinically significantly . Intestinal whipworm may also cause anemia . Anemia has also been associated with reduced stamina for physical labor , a decline in the ability to learn new information , and apathy , irritability , and fatigue . A study of the effect of deworming and iron supplementation in 47 students from the Democratic Republic of the Congo found that the intervention improved cognitive function . Another study found that in 159 Jamaican schoolchildren , deworming led to better auditory short - term memory and scanning and retrieval of long - term memory over a period of nine - weeks . Malnutrition due to helminths may affect cognitive function leading to low educational performance , decreased concentration and difficulty with abstract cognitive tasks . Iron deficiency in infants and preschoolers is associated with `` lower scores ... on tests of mental and motor development ... ( as well as ) increased fearfulness , inattentiveness , and decreased social responsiveness '' . Studies in the Philippines and Indonesia found a significant correlation between helminthiasis and decreased memory and fluency . Large parasite burdens , particularly severe hookworm infections , are also associated with absenteeism , under - enrollment , and attrition in school children . Of all the known helminth species , the most important helminths with respect to understanding their transmission pathways , their control , inactivation and enumeration in samples of human excreta from dried feces , faecal sludge , wastewater , and sewage sludge are : soil - transmitted helminths , including Ascaris lumbricoides ( the most common worldwide ) , Trichuris trichiura , Necator americanus , Strongyloides stercoralis and Ancylostoma duodenale Hymenolepis nana Taenia saginata Enterobius Fasciola hepatica Schistosoma mansoni Toxocara canis Toxocara cati soil - transmitted helminths , including Ascaris lumbricoides ( the most common worldwide ) , Trichuris trichiura , Necator americanus , Strongyloides stercoralis and Ancylostoma duodenale Helminthiases are classified as follows ( the disease names end with `` - sis '' and the causative worms are in brackets ) : Filariasis ( Wuchereria bancrofti , Brugia malayi infection ) Onchocerciasis ( Onchocerca volvulus infection ) Soil - transmitted helminthiasis -- this includes ascariasis ( Ascaris lumbricoides infection , trichuriasis ( Trichuris infection ) , and hookworm infection ( includes necatoriasis and Ancylostoma duodenale infection ) Trichostrongyliasis ( Trichostrongylus spp . infection ) Dracunculiasis ( guinea worm infection ) Baylisascaris ( raccoon roundworm , may be transmitted to pets livestock and humans ) Filariasis ( Wuchereria bancrofti , Brugia malayi infection ) Onchocerciasis ( Onchocerca volvulus infection ) Soil - transmitted helminthiasis -- this includes ascariasis ( Ascaris lumbricoides infection , trichuriasis ( Trichuris infection ) , and hookworm infection ( includes necatoriasis and Ancylostoma duodenale infection ) Trichostrongyliasis ( Trichostrongylus spp . infection ) Dracunculiasis ( guinea worm infection ) Baylisascaris ( raccoon roundworm , may be transmitted to pets livestock and humans ) Echinococcosis ( Echinococcus infection ) Hymenolepiasis ( Hymenolepis infection ) Taeniasis / cysticercosis ( Taenia infection ) Coenurosis ( T. multiceps , T. serialis , T. glomerata , and T. brauni infection ) Echinococcosis ( Echinococcus infection ) Hymenolepiasis ( Hymenolepis infection ) Taeniasis / cysticercosis ( Taenia infection ) Coenurosis ( T. multiceps , T. serialis , T. glomerata , and T. brauni infection ) Amphistomiasis ( amphistomes infection ) Clonorchiasis ( Clonorchis sinensis infection ) Fascioliasis ( Fasciola infection ) Fasciolopsiasis ( Fasciolopsis buski infection ) Opisthorchiasis ( Opisthorchis infection ) Paragonimiasis ( Paragonimus infection ) Schistosomiasis / bilharziasis ( Schistosoma infection ) Amphistomiasis ( amphistomes infection ) Clonorchiasis ( Clonorchis sinensis infection ) Fascioliasis ( Fasciola infection ) Fasciolopsiasis ( Fasciolopsis buski infection ) Opisthorchiasis ( Opisthorchis infection ) Paragonimiasis ( Paragonimus infection ) Schistosomiasis / bilharziasis ( Schistosoma infection ) Moniliformis infection Helminths are transmitted to the final host in several ways . The most common infection is through ingestion of contaminated vegetables , drinking water , and raw or undercooked meat . Contaminated food may contain eggs of nematodes such as Ascaris , Enterobius , and Trichuris ; cestodes such as Taenia , Hymenolepis , and Echinococcus ; and treamtodes such as Fasciola . Raw or undercooked meats are the major sources of Taenia ( pork , beef and venison ) , Trichinella ( pork and bear ) , Diphyllobothrium ( fish ) , Clonorchis ( fish ) , and Paragonimus ( crustaceans ) . Schistosomes and nematodes such as hookworms ( Ancylostoma and Necator ) and Strongyloides can penetrate the skin directly . Finally , Wuchereria , Onchocerca , and Dracunculus are transmitted by mosquitoes and flies . In the developing world , the use of contaminated water is a major risk factor for infection . Infection can also take place through the practice of geophagy , which is not uncommon in parts of sub-Saharan Africa . Soil is eaten , for example , by children or pregnant women to counteract a real or perceived deficiency of minerals in their diet . Specific helminths can be identified through microscopic examination of their eggs ( ova ) found in faecal samples . The number of eggs is measured in units of eggs per gram . However , it does not quantify mixed infections , and in practice , is inaccurate for quantifying the eggs of schistosomes and soil - transmitted helminths . Sophisticated tests such as serological assays , antigen tests , and molecular diagnosis are also available ; however , they are time - consuming , expensive and not always reliable . Disrupting the cycle of the worm will prevent infestation and re-infestation . Prevention of infection can largely be achieved by addressing the issues of WASH -- water , sanitation and hygiene . The reduction of open defecation is particularly called for , as is stopping the use of human waste as fertilizer . Further preventive measures include adherence to appropriate food hygiene , wearing of shoes , regular deworming of pets , and the proper disposal of their feces . Scientists are also searching for a vaccine against helminths , such as a hookworm vaccine . Broad - spectrum benzimidazoles ( such as albendazole and mebendazole ) are the first line treatment of intestinal roundworm and tapeworm infections . Macrocyclic lactones ( such as ivermectin ) are effective against adult and migrating larval stages of nematodes . Praziquantel is the drug of choice for schistosomiasis , taeniasis , and most types of food - borne trematodiases . Oxamniquine is also widely used in mass deworming programmes . Pyrantel is commonly used for veterinary nematodiasis . Artemisinins and derivatives are proving to be candidates as drugs of choice for trematodiasis . In regions where helminthiasis is common , mass deworming treatments may be performed , particularly among school - age children , who are a high - risk group . Most of these initiatives are undertaken by the World Health Organization ( WHO ) with positive outcomes in many regions . Deworming programs can improve school attendance by 25 percent . Although deworming improves the health of an individual , outcomes from mass deworming campaigns , such as reduced deaths or increases in cognitive ability , nutritional benefits , physical growth , and performance , are uncertain or not apparent . If complications of helminthiasis , such as intestinal obstruction occur , emergency surgery may be required . Patients who require non-emergency surgery , for instance for removal of worms from the biliary tree , can be pre-treated with the anthelmintic drug albendazole . Areas with the highest prevalence of helminthiasis are tropical and subtropical areas including sub-Saharan Africa , central and east Asia , and the Americas . Some types of helminthiases are classified as neglected tropical diseases . They include : Soil - transmitted helminthiases Roundworm infections such as lymphatic filariasis , dracunculiasis , and onchocerciasis Trematode infections , such as schistosomiasis , and food - borne trematodiases , including fascioliasis , clonorchiasis , opisthorchiasis , and paragonimiasis Tapeworm infections such as cysticercosis , taeniasis , and echinococcosis Soil - transmitted helminthiases Roundworm infections such as lymphatic filariasis , dracunculiasis , and onchocerciasis Trematode infections , such as schistosomiasis , and food - borne trematodiases , including fascioliasis , clonorchiasis , opisthorchiasis , and paragonimiasis Tapeworm infections such as cysticercosis , taeniasis , and echinococcosis The soil - transmitted helminths ( A. lumbricoides , T. trichiura , N. americanus , A. duodenale ) , schistosomes , and filarial worms collectively infect more than a quarter of the human population worldwide at any one time , far surpassing HIV and malaria together . Schistosomiasis is the second most prevalent parasitic disease of humans after malaria . In 2014 -- 15 , the WHO estimated that approximately 2 billion people were infected with soil - transmitted helminthiases , 249 million with schistosomiasis , 56 million people with food - borne trematodiasis , 120 million with lymphatic filariasis , 37 million people with onchocerciasis , and 1 million people with echinococcosis . Another source estimated a much higher figure of 3.5 billion infected with one or more soil - transmitted helminths . In 2014 , only 148 people were reported to have dracunculiasis because of a successful eradication campaign for that particular helminth , which is easier to eradicate than other helminths as it is transmitted only by drinking contaminated water . Because of their high mobility and lower standards of hygiene , school - age children are particularly vulnerable to helminthiasis . Most children from developing nations will have at least one infestation . Multi-species infections are very common . Even in areas of high prevalence , the frequency and severity of infection is not uniform within communities or families . A small proportion of community members harbour the majority of worms , and this depends on age . The maximum worm burden is at five to ten years of age , declining rapidly thereafter . Individual predisposition to helminthiasis for people with the same sanitation infrastructure and hygiene behavior is thought to result from differing immunocompetence , nutritional status , and genetic factors . Because individuals are predisposed to a high or a low worm burden , the burden reacquired after successful treatment is proportional to that before treatment . It is estimated that intestinal nematode infections cause 5 million disability - adjusted life years ( DALYS ) to be lost , of which hookworm infections account for more than 3 million DALYS and ascaris infections more than 1 million . There are also signs of progress : The Global Burden of Disease Study published in 2015 estimates a 46 percent ( 59 percent when age standardised ) reduction in years lived with disability ( YLD ) for the 13 - year time period from 1990 to 2013 for all intestinal / nematode infections , and even a 74 percent ( 80 percent when age standardised ) reduction in YLD from ascariasis . As many as 135,000 die annually from soil transmitted helminthiasis . The 1990 -- 2013 Global Burden of Disease Study estimated 5,500 direct deaths from schistosomiasis , while more than 200,000 people were estimated in 2013 to die annually from causes related to schistosomiasis . Another 20 million have severe consequences from the disease . It is the most deadly of the neglected tropical diseases . Helminth genera Common name Infections ( million per year ) Direct deaths per year Regions where common Soil transmitted helminthiasis ( STH ) ( classified as neglected tropical disease ) : Ascaris lumbricoides Roundworm 1000 to 1450 807 to 1,121 20,000 Many regions of South - east Asia , Africa , and Central and South America Trichuris trichiura Whipworm 500 604 -- 795 In moist , warm , tropical regions of Asia , Africa , Central and South America , and the Caribbean islands . Ancylostoma duodenale Hookworm 900 to 1300 576 -- 740 ( hookworm in general ) In tropical and subtropical countries ( Sub-Saharan Africa ) Necator americanus Strongyloides stercoralis Hookworm , pinworm 50 to 100 Thousands In moist rainy areas of the tropics and subtropics , in some areas of southern and eastern Europe and of the United States of America All STH together 1500 to 2000 135,000 Tropical and subtropical areas , in particular sub-Saharan Africa , the Americas , China and east Asia . Not transmitted via soil but classified as neglected tropical disease : Schistosoma mansoni Blood fluke All types of Schistosoma together : 160 to 200 ( 210 `` affected '' ) 12,000 150,000 deaths from renal failure 200,000 indirect deaths from `` causes related to '' Schistosomiasis In tropical and subtropical regions Schistosoma haematobium 112 ( in Sub-Saharan Africa alone ) Echinococcus granulosus Developing countries Not transmitted via soil and not classified as neglected tropical disease : Toxocara canis Dog roundworm 50 Many regions of South - east Asia , Africa , and Central and South America Taenia solium Pork tapeworm 50 South America , Southeast Asia , West Africa and East Africa Taenia saginata Beef tapeworm 50 ( all types of Taenia : 40 to 60 ) Hymenolepis nana Dwarf tapeworm 100 Hymenolepis diminuta Rat tapeworm Fasciola hepatica , Fascioloides magna Liver fluke 50 Largely in southern and eastern Asia but also in central and eastern Europe Fasciolopsis buski Giant intestinal fluke Dracunculus medinensis Guinea worm Nowadays negligible thanks to eradication program Formerly widespread in India , west Africa and southern Sudan Trichostrongylus orientalis Roundworm 1 -- 3 ( `` several '' ) Rural communities in Asia Other 100 Worldwide Total ( number of infections ) Approx . 3.5 billion Worldwide Helminth genera Common name Infections ( million per year ) Direct deaths per year Regions where common Soil transmitted helminthiasis ( STH ) ( classified as neglected tropical disease ) : Ascaris lumbricoides Roundworm 1000 to 1450 807 to 1,121 20,000 Many regions of South - east Asia , Africa , and Central and South America 807 to 1,121 Trichuris trichiura Whipworm 500 604 -- 795 In moist , warm , tropical regions of Asia , Africa , Central and South America , and the Caribbean islands . 604 -- 795 Ancylostoma duodenale Hookworm 900 to 1300 576 -- 740 ( hookworm in general ) In tropical and subtropical countries ( Sub-Saharan Africa ) 576 -- 740 ( hookworm in general ) Necator americanus Strongyloides stercoralis Hookworm , pinworm 50 to 100 Thousands In moist rainy areas of the tropics and subtropics , in some areas of southern and eastern Europe and of the United States of America All STH together 1500 to 2000 135,000 Tropical and subtropical areas , in particular sub-Saharan Africa , the Americas , China and east Asia . Not transmitted via soil but classified as neglected tropical disease : Schistosoma mansoni Blood fluke All types of Schistosoma together : 160 to 200 ( 210 `` affected '' ) 12,000 150,000 deaths from renal failure 200,000 indirect deaths from `` causes related to '' Schistosomiasis In tropical and subtropical regions ( 210 `` affected '' ) 200,000 indirect deaths from `` causes related to '' Schistosomiasis Schistosoma haematobium 112 ( in Sub-Saharan Africa alone ) Echinococcus granulosus Developing countries Not transmitted via soil and not classified as neglected tropical disease : Toxocara canis Dog roundworm 50 Many regions of South - east Asia , Africa , and Central and South America Taenia solium Pork tapeworm 50 South America , Southeast Asia , West Africa and East Africa Taenia saginata Beef tapeworm 50 ( all types of Taenia : 40 to 60 ) ( all types of Taenia : 40 to 60 ) Hymenolepis nana Dwarf tapeworm 100 Hymenolepis diminuta Rat tapeworm Fasciola hepatica , Fascioloides magna Liver fluke 50 Largely in southern and eastern Asia but also in central and eastern Europe Fasciolopsis buski Giant intestinal fluke Dracunculus medinensis Guinea worm Nowadays negligible thanks to eradication program Formerly widespread in India , west Africa and southern Sudan Trichostrongylus orientalis Roundworm 1 -- 3 ( `` several '' ) Rural communities in Asia Other 100 Worldwide Total ( number of infections ) Approx . 3.5 billion Worldwide
Necator americanus