Distinguishing Diarrheas: searching for an association between Giardia lamblia and irritable bowel s

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Distinguishing Diarrheas searching for an
association between Giardia lamblia and irritable
bowel syndrome

• Alice Penrose, MD, MPH
• Eden Wells, MD, MPH
• Allison Aiello, PhD
• Michigan Epidemiology Conference
• April 12, 2007

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GIARDIA LAMBLIA

• Tear drop-shaped, multi-flagellate, bi-nucleated
  protozoa capable of causing gastrointestinal
  illness in humans by the fecal oral route of
  infection

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GIARDIASIS

• Case Definition Detection of Giardia
  intestinalis cysts, trophozoites, or antigens by
  immunodiagnostic testing, in stool specimens,
  duodenal fluid, or small bowel tissue MMWR
  January 28, 2005

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GIARDIASIS PRESENTATION

• Incubation one to two weeks
• Onset gradual
• Symptoms nausea, vomiting, malaise, flatulence,
  bloating, cramping, mild diarrhea, steatorrhea
• Sequelae malabsorbtion, lactase deficiency,
  weight loss, fatigue, depression and rarely
  reactive arthritis or urticaria
• Diagnosis by microsope or immunoassay

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GIARDIASIS INCIDENCE

• 16,631 reported cases in the US in 2005
• CDC estimates true yearly incidence 0.15 to 0.7
• Increased incidence
• Late summer and early fall
• Northern states
• Immigrants from developing countries
• Men who have sex with men
• Children under 5 years of age
• Daycare center personnel

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IRRITABLE BOWEL SYNDROME

• Abdominal pain relieved with defecation
• Change in stool frequency
• Change in stool consistency
• Urgency of bowel movements
• Passage of mucus
• Bloating or abdominal discomfort
• 3 months of symptoms (continuous or recurrent)

Rome criteria
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PREVIOUS RESEARCH

• 2002 Gastrointestinal disorders in Guatemala and
  their relation with parasitic infections Bujanda
  et al. Annales de Medicina Interna
• 2004 Diagnostic value of limited research in
  patients with irritable bowel syndrome Martinez
  Revista de Gastroenterolgia de Mexico
• 2006 Giardia lamblia infection in patients with
  irritable bowel syndrome and dyspepsia Grazioli
  et al. World Journal of Gastroenterology
• 2002 Giardia lamblia infections become clinically
  evident by eliciting symptoms of Irritable Bowel
  Syndrome DAnchino et al. Journal of Infection

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THEORY

• Irritable bowel syndrome is positively associated
  with Giardia infection.

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Sources of Data

• Michigan Disease Surveillance System
• Blue Cross Blue Shield Prescription Data
• Office of Refugee Services

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REPORTED CASES

• Year US
  Michigan
• 2002 16,631 904
• 2003 19,195 754
• 2004 20,648 733
• 2005 16,631 786

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Number of Giardiasis cases
Age in years
Figure 2. Michigan Giardia lamblia cases by age
in 2005
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MICHIGAN GIARDIASIS CASES

• MDSS
• Male 54
• African 6
• Asian 4
• European 90
• Native lt1
• Hispanic 6

• CDC
• Male 55
• African 7
• Asian 4
• European 88
• Native lt1
• Hispanic 15

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Frequency of counties
Giardia lamblia cases per 100,000 persons
Figure 1. Frequency of Michigan counties by
Giardia lamblia incidence in 2005
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BCBS PRESCRIPTIONS

• Bentyl (dicyclomine)
• Zelnorm (tegaserod)
• Lotronex (alosetron)

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Frequency of Counties
Number of prescriptions for IBS per 1000 members
per month
Figure 3. Frequency of counties by Michigan BCBS
prescription incidence for 2005
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Figure 4. Michigan Giardia lamblia incidence
versus BCBS prescriptions for IBS
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Giardia cases per 100,000 by health jurisdiction
ZERO
0.1-4.33
4.34-8.66
8.67-13.00
13.01-21.66
21.67-30.32
39.00-43.32
MDCH, unpublished data
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County
Giardia
Population
Giardia Rate
Refugees
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SUMMARY

• Giardiasis cases were not predictive of
  prescription drug use by county in Michigan
• Refugee numbers were predictive of Giardiasis
  rates by county in Michigan

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ACKNOWLEDGEMENTS

• Brad Carlson MDSS
• Jim Collins MDSS
• Elizabeth Lewis MDSS
• Jim Rudrick Michigan Bureau of Labs
• Ann Mattson MDCH Library
• Fred Fedorowicz BCBS of Michigan
• Al Horn Office of Refugee Services