Neglected Tropical Diseases - UT Southwestern

Global Health Pre-Trip SessionHelminthic infections seen in developing nations:Neglected Tropical Diseases!Paul M Southern, MD, DTM&H2013

Diseases to be coveredAscariasis: Ascaris lumbricoidesEchinococcosis (cystic hydatid): Echinococcus granulosusHookworm: Ancylostoma duodenale, Necator americanusLymphatic filariasis: Wuchereria bancrofti, Brugia malayi, B. timoriOnchocerciasis: Onchocerca volvulus Schistosomiasis: Schistosoma mansoni, S. haematobium, S. japonicum, S. intercalatum, S.mekongiStrongyloidiasis: Stongyloides stercoralisTaeniasis: Taenia solium, T. saginata, cysticercosisTrichuriasis: Trichuris trichiura

Diseases NOT coveredEnterobiasis (pinworm): Enterobius vermicularis Filaria (others): Loa loa, Mansonella ozzardi, M. perstans, M.streptocerca, Dirofilaria spp.Intestinal cestodes (rarer): Hymenolepis nana, H. diminuta, Dipyllidiumcaninum, Diphyllobothrium latum, agents of SparganosisIntestinal nematodes (rarer): Capillaria philippinensis, Trichostrongylusspp.Other trematodes: intestinal, liver, lungTissue nematodes: manyNot covering ANY protozoa, despite their great importance

Global Estimates of number of soiltransmittedhelminths (millions), WHO Ascariasis: 1,222 Trichuriasis: 795 Hookworm: 740 Strongyloidiasis: ~500** = incomplete data

Estimated number of DALYs lost(thousands) by cause [helminths only]* Schistosomiasis: 1,707 worldwide, 1,502 Africa Lymphatic filariasis: 5,941 worldwide, 2,263 Africa, 3,525SE Asia Onchocerciasis: 389 worldwide, 375 Africa Ascariasis: 1,851 worldwide, 915 Africa, 404 SE Asia Hookworm: 1,092 worldwide, 377 Africa, 286 SE Asia* WHO data; DALY = disability-adjusted life years

Cost-effectiveness of controlling neglectedtropical diseases (Cost per DALY averted in$US) Lymphatic filariasis: 35 – 370 (depends on region) Schistosomiasis: 10-23, or as much as 844 (depends onstrategy) Onchocerciasis: 9 Soil-transmitted helminths: 2-11 (mass school treatment)(Includes hookworm, ascariasis, whipworm)

WHO-recommended anthelminthic drugs fortreatment or preventionDiseaseIvermectinAscariasis + + - (+) - + +Hookworm+ + - - - + +Lymphatic filariasis+ - + + - - -AlbendazoleMebendazoleDiethylcarbamezinePraziquantelLevamisoleOnchocerciasis- - - + - - -Schistosomiasis- - - - + - -Trichuriasis+ + - (+) - (?) (?)Otherflukes- - - - + - -Strongyloidiasis+ (+) - + - - -Taeniasis- - - - + - -Pyrantel

Morbidity associated with soiltransmittedhelminths* Intestinal bleeding: HookwormMalabsorption syndromes: AscariasisCompetition for micronutrients: AscariasisImpaired growth: AscariasisAnorexia, reduced food intake: AscariasisDiarrhea or dysentery: TrichuriasisCognitive impairment: TrichuriasisIntestinal obstruction: Ascariasis Rectal prolapse: Trichuriasis* Montresor, et al.TRSTMH.2010;104:129-32

Taenia

Taenia solium

Taenia saginata

T. soliumT. saginata

CLASSIFICATION OF PATHOGENIC ANDCOMMENSAL HUMAN PARASITESB. TISSUE CESTODES (Larval)1. Taenia solium (cysticercoisis)2. Echinococcus granulosus (hydatid cysts)3. Echinococcus multilocularis (alveolar hydatid)4. Multiceps spp. (Taenia multiceps) “Coenurosis”, “Coenuriasis”5. Spirometra mansoni, Spirometra mansonoides, others (Sparganosis)

ECHINOCOCCOSIS(Hydatid Disease)Causative Agents:Manifestations:Diagnosis:Treatment:Echinococcus granulosusUnilocular, simple cysts, cystic hydatidEchinococcus multilocularisAlveolar, complex cystsEchinococcus oligarthrus}Echinococcus vogeli }Polycystic hydatidCysts in liver, spleen, lung, bone, kidney, muscles, brain,myocardiumClinical history and examination, imaging techniques,serological tests (ELISA, CF, IHA, arc-5 double-diffusionassay, enzyme-linked immunotransfer blot), hydatid sandin cyst at surgerySurgery, pre-and postoperative albendazole with orwithout praziquantel (scolicidal); albendazole dosage 400mg BID X 28 days, repeat if necessary; PAIR

Echinoccosis granulosus

CT Scan of Abdomen,transverseCT Scan of Abdomen, verticalView at Surgery

Surgical specimen from prior patient

Intestinal obstruction due to Ascaris lumbricoides

Hookworm Life Cycle

Larva currens

Rhabditiform larva of Strongyloides stercoralis

Strongyloides stercoralis on stoolculture plate

Taken from:

Wuchereria bancrofti microfilaria in peripheral blood

nucleitipsheath

Brugia malayi microfilaria

Brugia malayi, separation of last nuclei

Onchocerca volvulus, life cycle

Geography of epidemiology

Black fly, (Simulium damnosum)

Schistosome Map, 2006

Major Schistosomes, life cycle

Egg Schistosoma intercalatum

Schistosoma spp. epidemiology

Epidemiology of S. mansoni and S. haematobium inAfricaCote d’IvoireSenegal

Epidemiology of S. mansoni and S.haematobium in AfricaBeautiful Lake Malawi: notorious as a prime site fortransmission of schistosomiasis

S. japonicum, mekongiSimilar pathogenesis as S. mansoniMore CNS lesions in S. japonicumSalmonella bacteremic infections mayoccur with most species ofSchistosoma

S. Japonicum Asia

S. japonicum, Asia

Transmission of S. japonicum inChinaAgricultural irrigationditch

S. japonicum, S. mekongi

The End