Intestinal Parasites. James Gaensbauer MD, MScPH Fellow, Pediatric Infectious Diseases University of Colorado School of Medicine November 12, 2012

Transcription

1 Intestinal Parasites James Gaensbauer MD, MScPH Fellow, Pediatric Infectious Diseases University of Colorado School of Medicine November 12, 2012

2 Outline Parasites 101 Global Burden of Disease An Evolutionary Perspective A Societal Perspective Global Public Health Response

3 Parasites 101

4 Classification of Macroparasites Protozoa--first animals Platyhelminths--flat worms Nematodes--round Acanthocephala--thorny headed Arthropods--jointed feet

5 Protozoa Platyhelminths Cestodes Trematodes Nematodes Intestinal Entamoeba Giardia Cryptosporidium Taenia (ingested larvae) Diphyllobothrium Ascaris Hookworms Strongyloides Trichuris Tissue/Blood Malaria Leishmania Naeglaria Toxoplasma Taenia/cysticercosis (ingested eggs) Echinococcus Schistosoma Fasciola Clonorchis Trichonella Druncunculus Angiostrongylus Filaria

6 Name that Egg

7 The global burden of intestinal parasitic disease

8 Adverse Effects: Soil Transmitted Helminths Ascaris Hookworm Acute Effects Pulmonary Hypersensitivity Bile duct obstruction Liver abscess Intestinal obstruction Ground Itch Abdominal Pain Chronic Effects Malabsorption Nutritional deficency Growth Retardation Congnitive delay Anemia Cognitive Delay Trichuris Trichuris Dysentery Nutritional deficiency Growth retardation Cognitive Delay

9 Burden of Intestinal Parasitic Infection Soil Transmitted Helminths Ascaris 1 billi on Hookworms 740 milli on Trichuris 795 milli on Strongyloides milli on Cestodes Taeniasis 2.5 million Cysticercosis 100 milli on (50,000 deaths/year) Protozoa Giardia 2% adult/8% children Entamoeba 50 milli on Cryptococcus >1 billi on World Health Organization, 2012; Hotez 2008, CDC 2012

10

11 Global Burden of Parasitic Disease: Disability Adjusted Life Year. DALY s by age and cause (millions) Total 0-4 yr 4-15 yr Tuberculosis Diarrheal Disease Malaria HIV/AIDS Dengue Intestinal Nematode infections World Health Organization, 2004

12 Name this egg

13 Name this egg

14 Intestinal Parasites: Evolutionary Perspective

15 Intestinal Parasites: Evolutionary Perspective

16 Immune Response to Helminth infection Parasite Killing Tissue Damage Parasite IFN-γ IL-17 IL-4 Th2 Th1 x IL-10 Immune Modulation Protective Immunity Tissue Healing

17 Challenges to Vaccine Development: Hookworm Vaccine Schneider, 2011

18 Hygiene Hypothesis Yazdanbakhsh, 2002

19 Impact of intestinal infection on immunity Viral HIV Bacterial Cholera Tuberculosis Parasitic Malaria Vaccine Immunity? Cholera vaccine BCG Tetanus Numerous Animal models

20 Name that head

21 Intestinal Parasites: Societal Perspective Intrinsic link to poverty: Lack of sanitation/infrastructure Contamination of soil Contamination of food/water supply Inadequate education/awareness

22 Neglected Tropical Diseases Soil Transmitted Helminths Schistosomiasis Lymphatic filariasis Trachoma Onchocerciasis Leishmaniasis Chagas disease Leprosy Trypanosomiasis Dracunculiasis Buruli Ulcer Cysticercosis Dengue Rabies Yaws Echinococcus Fascioliasis

23 USAID: NTD treatments

24 Name that egg

25 Global Public Health Response Development Related Interventions Improved sanitation Prevention of fecal contamination of food and water supply Hygeine Education Economic development

26 Meta-analysis of sanitation to prevent Helmenthiasis. Ziegelbauer, 2012

27 Deworming Programs Periodic Therapy Universal Targeted Selective Frequency Medication Benzimidazoles Vitamin A supplementation Monitoring QuickTime and a decompressor are needed to see this picture.

28 Deworming Programs: Effectiveness Universal impact varies Greatest improvements occur when: Hookworm is a predominant parasite and anemia is the primary outcome Iron supplementation complements deworming Treatment begins at early age Doses are given 3 times/year vs. 2 in high prevalence areas Primary intervention is Vitamin A supplementation

29 Future Directions Vaccination Technology New anti-helminth medications Outside the box strategies (eg. Wolbachia)

30 Questions