Presentation is loading. Please wait.

Presentation is loading. Please wait.

Intestinal Nematodes and Eosinophilia

Similar presentations

Presentation on theme: "Intestinal Nematodes and Eosinophilia"— Presentation transcript:

1 Intestinal Nematodes and Eosinophilia
Patricia F Walker, MD, DTM&H Medical Director, HealthPartners Center for International Health Associate Professor, Division of Infectious Disease and International Medicine University of Minnesota Healthcare in the Global Village: Serving Refugees in Indiana Indianapolis, Indiana September 25, 2009

2 Parasitic Helminths Trematodes (flukes) Cestodes (tapeworms)
Venous system: Schistosoma Biliary tract: Clonorchis, Fasciola Lung: Paragonimus Cestodes (tapeworms) Taenia saginata, Taenia solium, H. nana Nematodes (roundworm) Intestinal Blood, lymphatic, subcutaneous

3 Lecture Overview General Facts about Intestinal Nematodes 4 major intestinal nematodes: Ascaris, Trichuris, hookworm and Strongyloides Public Health Implications Lifecycle Clinical presentation Treatment Trends in Intestinal Parasitism among Refugees

4 General Facts about Intestinal Nematodes
Frequently nonspecific symptoms Often asymptomatic until worm burden becomes large Weight loss, GI discomfort Diarrhea or fever from nematodes is uncommon Polyparasitism Burden is greatest in children

5 General Facts about Intestinal Nematodes
Tropical and subtropical predominance Don’t multiply in host 2 exceptions Infection limited to life span of worm unless reinfection occurs Lifespan: 2 months – 5 years Rare Exceptions: Strongyloides, C. philippinensis: autoinfection Pinworm: self-reinfection

6 Soil Transmitted Helminths (STH) = Geohelminths
Part of development occurs in the soil Average 3 – 4 weeks in soil until infective Infection via eggs in contaminated soil (Ascaris, Trichuris) or skin penetration (hookworm) Ecology of geohelminth infection In tropical and subtropical areas, wet soil (such as that found at the edges of rice fields, rubber plantations and the surroundings of villages in areas of high rainfall) supports the maturation of hookworm larvae from eggs deposited by indiscriminate defaecation; this limits their geographical distribution. In contrast, the well-protected eggs of nematodes with a direct cycle of transmission (Ascaris lumbricoides, Trichuris trichiura) can survive in drier conditions even at freezing temperatures.

7 Soil Transmitted Helminths (STH)
Infection rates and burden of disease greatest among conditions of poverty, poor sanitation

8 Guatemalan Children With Soil–Transmitted Helminth Infections
Stunting, anemia, loss of IQ, diminished school performance Many years of lost primary schooling attributable to STH

9 Parasite Prevalence in Village of Paquila, Guatemala
100 80 60 Prevalence (%) 40 20 0 – 3 4 – 7 8 – 12 Age Class (y) Ascaris Trichuris Hookworm Strongyloides

10 Highest Worm Burdens in School-aged Children

11 Growth Curve of Child With Soil-transmitted Infection

12 Ascaris lumbricoides 1/8th the world’s population infected Largest of nematodes infecting humans Adult habitat: small intestine (jejunum) Obligatory extra-intestinal migration (eosinophilia) Lifespan: 1 – 2 years Intensity of infection greatest in children, ages 5 – 10 years

13 Ascaris infection in Haiti and Paraguay

14 Ascaris Lumbricoides Eighty-nine hookworms and 81 Ascaris. This demonstration induced many to apply for treatment (Brazil).

15 Geographic prevalence highest in warm, wet climates
Ascaris Geographic prevalence highest in warm, wet climates 1 adult female = 200,000 eggs/day

16 Pre-patency: 2 months Pneumonitis: 4 – 16 days after infection, short duration (~3 wks)

17 Löeffler Syndrome (Pneumonitis)
Transverse sections of Ascaris larvae in pulmonary alveoli 460 Transverse sections of Ascaris lumbricoides larvae in the pulmonary alveoli This post-mortem specimen shows transverse sections of larvae and eosinophilic infiltration of the alveolar walls. (Courtesy of Dr A M de Oliviera Ramos.) (H&E × 300)

18 Ascaris lumbricoides Larval phase: eosinophilia, pneumonitis Adult phase: Malnutrition, Impaired Physical Growth Mild abdominal discomfort → → Small bowel obstruction (in children, few as 60 worms) Wandering ascaris: biliary tract obstruction, cholangitis, pancreatitis, liver abscess Treatment: Albendazole x 1 dose

19 Adult Ascaris worms migrating in liver
465 Adult roundworms migrating in liver The adult worms have a marked tendency to penetrate any available hole in their vicinity and may escape through abdominal fistulae following operation. They may also lead to biliary obstruction and occupy the appendix.

20 Ascaris causing intestinal obstruction.

21 Acute G.I. Obstruction from Ascaris

22 Interesting e mails… Sent: Monday, April 04, :32 PM To: Subject: health needs I got your address from my mother- Linda  A. I am an ELL teacher and have many students from Liberia.  I had a student complain about coughing up a long white worm as he was eating a lemon at lunch.  I sent him to the nurse at school, as he said this was the second time it has happened to him.  She sent him back to class saying there wasn't enough to tell anything at this point.  Is there anything you can suggest, or anywhere I can direct his parents? Thanks for your help! Michelle R  

23 Ascaris (roundworm): The only nematode ever coughed or vomited up

24 Whipworm: Trichuris trichiuria
Adult habitat: caecum, colorectum No extra-intestinal phase Lifespan: years 90% infections are asymptomatic Symptoms with heavy infections Intensity of infection peaks by age 10

25 Pre-patency: 2 months

26 Whipworm: Trichuris trichiuria
Clinical Features: Asymptomatic Physical Weakness, Anemia Stunted Growth, Cognitive Deficits Stool frequency (12+/day), nocturnal stooling Trichuris dysentery syndrome Trichuris colitis Rectal prolapse Treatment: Albendazole x 3 days.

27 Whipworm: Trichuriasis Colitis

28 Rectal Prolapse from Trichiuriasis

29 Whipworm Egg: 2 polar plugs

30 The Human Hookworms Necator americanus Ancylostoma duodenale

31 Hookworm: Necator americanus & Ancylostoma duodenale
One – tenth the world’s population infected Significant cause of anemia & protein malnutrition Adult habitat: small intestine Lifespan: ~ 1 year (A. duodenale) ~ years (N. americanus) Worm burdens do not decline in adult years

32 Typical Age and Intensity of Infection Relationship
100 90 80 Trichuris 70 Hookworm 60 Mean Worm Burden (%) 50 Ascaris 40 30 20 10 10 20 30 40 Mean Age (y)

33 Human Hookworm Infection
~600 million cases worldwide (rural poverty >>> urban slums) 44 million pregnant women infected Iron-deficiency anemia: Physical & Intellectual Retardation Necator americanus is the predominant hookworm species

34 Life Cycle of Hookworm Pre-patency: months - year

35 Adult worms injure their host by causing intestinal blood loss:
Hookworm-Blood Loss Adult worms injure their host by causing intestinal blood loss: Anticoagulants, Hemolysins, and Hemoglobinases 30 to 200 μL blood per day per hookworm Intestinal blood loss and Iron Deficiency Anemia

36 Adult Hookworms in Situ (1 cm)
Adult size: 0.5 ─ 1 cm Daily eggs per worm: 5 ─ 20,000 430 Adult hookworms in situ The worms are about 1 cm long and characteristically curved. They are attached by their buccal capsules to the villi of the small intestine. (Natural size)

37 Hookworm: Clinical Features:
Ground-itch –> Dry cough, wheezing (1-2 wks later) in primary infection Abdominal discomfort Progressive iron-deficiency anemia 40 – 160 worms associated with Hgb < 11 g/dL Failure to thrive, extreme fatigue IQ loss Treatment: Albendazole x 1 dose

38 Hookworm Disease Pallor and Facial Edema Anasarca

39 At-Risk Populations for Hookworm Disease
Women and Children: Low Iron Stores Children: Physical growth stunting Cognitive deficits and intellectual retardation Women of Child-bearing age Puberty Menstruation Pregnancy Increased Maternal Mortality (anemia) Low Birthweight Infant Mortality

40 School Based Deworming
In 2001, (WHO) adopted a resolution aimed at the “deworming” of 75 percent of all at-risk school-age children by 2010, Prevention and Improvements in iron, Hgb status Improved Cognition, Educational Achievement Reduction in school absenteeism Reduction in community helminth transmission of ascariasis & trichuriasis

41 Control Anti-helminthic drugs:
50 million tablets of mebendazole donated per year by Johnson & Johnson Albendazole available from GlaxoSmithKline for 2¢ per pill Currently no vaccine exists for ascariasis or trichuriasis Human Hookworm Vaccine Initiative (HHVI): Phase I trials

42 Strongyloidiasis: Strongyloides stercoralis
Worldwide prevalence: ~100 million Adult habitat: duodenum, jejunum Lifespan: unknown. Ongoing autoinfection.

43 Strongyloidiasis - Clinical Presentation
Asymptomatic eosinophilia Abdominal pain Dermatitis - larva currens Pulmonary infiltrates with eosinophilia Dissemination with sepsis

44 Strongyloides. by ethnicity Regions Hospital, St
Strongyloides* by ethnicity Regions Hospital, St. Paul, MN 1/1/88 - 9/1/98 Ethnicity N % Cambodian Hmong Vietnamese African Hispanic 4 2.5 Laotian Unknown % Microbiology Lab Regions Hospital * Positive stool specimens

45 Documented length of infections in years
Adapted from Hospital for Tropical Disease London, 1997

46 Pruritic Larva Currens from Strongyloides
Larva currens = autoinfection with Strongyloides filariform larvae Moves rapidly (2 ─ 10 cm/hr), lasts shorter than CLM

47 Filariform Larvae (penetrating)
Strongyloides Rhabditiform Larvae may transform to Filariform Larvae… penetrating perianal skin and bowel mucosa Rhabditiform Larvae Adult Filariform Larvae (penetrating) Copyright © 2006, 1999 by Elsevier Inc.

48 Strongyloidiasis Hyperinfection: Strongyloides stercoralis
intestinal perforation hemorrhagic pneumonia shock, sepsis, gram-negative meningitis eosinophilia may be limited

49 Vietnamese male, in US for 8 years, developed fever, rash and pneumonia after being placed on steroids for uveitis.

50 FIGURE 285-2. Eggs and larvae of common intestinal roundworms
FIGURE Eggs and larvae of common intestinal roundworms. Clockwise, beginning at upper left: Ascaris lumbricoides; Trichuris trichiura; hookworm; Enterobius vermicularis; Strongyloides stercoralis; and embryonated hookworm egg. (From DPDx, website for laboratory diagnosis of parasitic diseases of the Division of Parasitic Diseases, National Centers for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA: [


52 Good news: Pre-departure treatment for intestinal parasites in US bound refugees
Since May, 1999 CDC has implemented empiric treatment with single dose albendazole 600 mg for all refugees departing from sub Saharan Africa, and for selected groups, such as Hmong arriving from Thailand in 2005

53 Prevalence of Intestinal Parasites Among Refugees Arriving in Minnesota, pre-May 1999 (n = 4,584)
Giardia Hookworm Trichuris Ascaris Strongyloides Any helminth Multiple helminths 21.5% Percentage 10.2% 8.7% 8.2% 3.7% 3.1% 2.3% Pre Post Pre Post Pre Post Pre Post Pre Post Pre Post Pre Post Giardia Hookworm Trichuris Ascaris Strongy -loides Any helminth Multiple helminths

54 Prevalence of Intestinal Parasites Among Refugees Arriving in Minnesota, pre/post-May (n = 18,015) Giardia Hookworm Trichuris Ascaris Strongyloides Any helminth Multiple helminths 21.5% Percentage 10.2% 8.5% 8.7% 8.2% 8.4% 4.6% 3.7% 3.1% 2.3% 0.6% 0.3% 0.5% 0.6% Pre Post Pre Post Pre Post Pre Post Pre Post Pre Post Pre Post Giardia Hookworm Trichuris Ascaris Strongy -loides Any helminth Multiple helminths

55 To Review… General Truths about Nematodes
Polyparasitism Burden greatest in children except hookworm, ?Strongyloides Don’t Multiply in Host (2 exceptions) Eosinophilia = tissue invasion Larval stages or Strongyloides

56 Recommended References
TROPICAL INFECTIOUS DISEASES Principles, Pathogens, & Practice, Second Edition, 2006 Guerrant, Walker, Weller Churchill Livingstone MANSON’S TROPICAL DISEASES Twenty-first Edition, 2003 Cook & Zumla W.B. Saunders ATLAS OF TROPICAL MEDICINE & PARASITOLOGY Sixth Edition, 2007 Peters & Pasvol Mosby Elsevier RED BOOK 2006 Report of the Committee on Infectious Diseases Table Drugs for Parasitic Infections

57 Acknowledgements for Slides
Stephen Swanson, MD, DTM&H, Hennepin County Medical Center, Minneapolis Peter Hotez, MD, PhD, FAAP President, Sabin Vaccine Institute Microbiology, Immunol, & Tropical Medicine The George Washington University School of Medicine

58 Post test with answers What is the most likely worm to be coughed or vomited up?
Trichuris Hookworm Strongyloides Tapeworm Ascaris

59 Which worm infection do you ALWAYS want to treat?
Ascaris Trichuris Strongyloides Pinworm Hookworm

60 Which worm’s burden of illness increases through your late childhood and early adulthood years?
Strongyloides Hookworm Ascaris Trichuris Pinworm

61 Which worm infection is most likely to mimic colitis?
Trichuris Ascaris Strongyloides Pinworm Hookworm

62 Which Nematode is the most likely to be the cause of eosinophilia in an immigrant/refugee from Africa who has been in America x 9 months? Trichuris Strongyloides Pinworm Hookworm Ascaris

63 When is the ideal time to check Stool O & P in Returning Traveler?
IMMEDIATELY upon landing Within 1 week 1 month 2 month 6 months 1 year

Download ppt "Intestinal Nematodes and Eosinophilia"

Similar presentations

Ads by Google