Environmental transmission of Cryptosporidium parvum: research update

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Environmental transmission of Cryptosporidium
parvum research update

• Alex Grinberg
• Infectious Diseases and Public Health Group
• Massey University, IVABS

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• A review of some international develpments in C.
  parvum epidemiology
• Preliminary data on the molecular epidemiology of
  C. parvum in NZ

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Dillingham RA, Lima AA, Guerrant RL.
Cryptosporidiosis epidemiology and impact.
Microbes and Infection 4, 59-66, 2002.
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Simplistic C. parvum bovine-human cycling model
Difficult to quantify
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Complex C. parvum cycling model anthroponotic
C. parvum

• Mallon et al (2003), based on a simple inspection
  of an UPGMA dendrogram
• Xiao et al (2004)
• Grinberg et al 2007

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Anthroponotic (human-only) C. parvum cycling
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Grinberg et al, 2007
36 MLGs
18 MLGs
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• Results
• MLG richness difference is greater than the
  expected difference between two samples drawn
  from a non-partitioned pop., when stochastic
  sampling variation alone is operating.
• .

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Model 1 Model 2
Possible explanatory models

• Human C.parvum

Human C.parvum
Bovine C. parvum
Bovine C. parvum
Human infections caused by parasites not
originating from regional bovine reservoirs
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New Zealand C. parvum
A. Grinberg, G Widmer et al. submitted
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C. parvum in NZ

• Preliminary data based on sequencing of two
  highly polymorphic loci (GP60 and HSP70 genes)

Human
Bovine
Foal
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An important new development C. bovis

• A new Crypto species of young cattle
• Highly prevalent in calves gt 1 month of age
• Has never been identified in humans
• C. bovis DNA signature identified in one calf in
  NZ (unpublished observation)