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Cryptosporidium and Giardia in Sheep...

Vodovoz, Tamara.

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Cryptosporidium and Giardia in Sheep in California: Prevalence, Shedding intensity, Risk Factors and Molecular Characterization of Cryptosporidium Species.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Cryptosporidium and Giardia in Sheep in California: Prevalence, Shedding intensity, Risk Factors and Molecular Characterization of Cryptosporidium Species./
Author:	Vodovoz, Tamara.
Description:	120 p.
Notes:	Source: Dissertation Abstracts International, Volume: 74-10(E), Section: B.
Contained By:	Dissertation Abstracts International74-10B(E).
Subject:	Environmental Health. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3565407
ISBN:	9781303151361

Cryptosporidium and Giardia in Sheep in California: Prevalence, Shedding intensity, Risk Factors and Molecular Characterization of Cryptosporidium Species.
Vodovoz, Tamara.

Cryptosporidium and Giardia in Sheep in California: Prevalence, Shedding intensity, Risk Factors and Molecular Characterization of Cryptosporidium Species. - 120 p.

Source: Dissertation Abstracts International, Volume: 74-10(E), Section: B.

Thesis (Ph.D.)--University of California, Davis, 2013.

A study was conducted to investigate the prevalence, shedding intensity, and identification of risk factors associated with the presentation of Cryptosporidium and Giardia duodenalis in sheep ranches in central and northern California, USA. A total of 798 fecal samples from 372 adult ewes, 31 yearlings and 395 lambs were collected from 16 farms. At each ranch, information was collected on each individual sheep and ranch management practices as potential risk factors. Information collected included: sheep age, sex, body condition score, fecal consistency, flock size, number of ewes and lambs in flock, pasture rotation and size, lambing period, access to surface water, contact with cattle, production type, geographical location, etc. Cryptosporidium oocyst and G. duodenalis cyst were detected and numbered in feces using a direct immune-fluorescent assay. DNA was extracted, and the SSU rRNA gene was amplified by nested PCR and sequenced for phylogenetic analysis and molecular characterization of a subset of 74 Cryptosporidium positive samples. The overall prevalence of Cryptosporidium was 30.6% in lambs, 16.1% in yearlings and 3.2% in adult ewes; peak prevalence was observed in two (37.4%) and three (38.3%) month old lambs. The prevalence of G. duodenalis was 48.1% in lambs, 45.1% in yearlings and 15.2% in adult ewes; peak prevalence was observed in four (83.3%) and five (76.9%) month old lambs. Based on an estimated fecal production of 2.5% body weight per day, the environmental loading rate of Cryptosporidium oocyst was estimated to range from 0.5 x106 to 6.8 x106 for lambs, from 2.9 x104 to 4.4 x104 for yearlings, and from 0.3 x106 to 1 x106 for ewes. The environmental loading rate of G. duodenalis cysts was estimated to range from 3 x106 to 34 x106 for lambs, from 16 x10 6 to 24 x106 for yearlings, and from 3 x106 to 8.7 x106 for ewes. Statistical analysis showed that access to drink surface water, and contact with cattle significantly increased the odds of Cryptosporidium shedding in sheep of all ages. Reduced odds of shedding Cryptosporidium was observed in lambs as the number of ewes increased in the flock and in adult ewes as the pasture size increased. In addition to drinking surface water, the odds of G. duodenalis also increased in sheep that were grazing on irrigated pastures. Ewes lambing in a pasture with access to a barn, and moving the newly born lamb with the ewe mother to a new and clean pasture after lambing presented reduced odds of shedding G. duodenalis in lambs and ewes. Diarrhea was not associated with Cryptosporidium or G. duodenalis shedding in sheep. Lower body condition scores were associated with G. duodenalis shedding in adult ewes. Cryptosporidium xiaoi was the most common species found in 89.2% (66/74) positive sheep samples evaluated. A subset of 6 samples were confirmed as C. xiaoi at the actin gene level. The zoonotic C. ubiquitum was found in 8 lambs, representing 11% (8/74) of the population evaluated. Cryptosporidium ubiquitum ubiquitum sequences were identical to isolates previously reported in human and sheep infections worldwide. The low prevalence of C. ubiquitum indicate that lambs can be considered a minor source of zoonotic Cryptosporidium in California.

ISBN: 9781303151361Subjects--Topical Terms:

578282
Environmental Health.

Cryptosporidium and Giardia in Sheep in California: Prevalence, Shedding intensity, Risk Factors and Molecular Characterization of Cryptosporidium Species.
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245 1 0 $a Cryptosporidium and Giardia in Sheep in California: Prevalence, Shedding intensity, Risk Factors and Molecular Characterization of Cryptosporidium Species.
300 $a 120 p.
500 $a Source: Dissertation Abstracts International, Volume: 74-10(E), Section: B.
500 $a Adviser: Edward E. Atwill.
502 $a Thesis (Ph.D.)--University of California, Davis, 2013.
520 $a A study was conducted to investigate the prevalence, shedding intensity, and identification of risk factors associated with the presentation of Cryptosporidium and Giardia duodenalis in sheep ranches in central and northern California, USA. A total of 798 fecal samples from 372 adult ewes, 31 yearlings and 395 lambs were collected from 16 farms. At each ranch, information was collected on each individual sheep and ranch management practices as potential risk factors. Information collected included: sheep age, sex, body condition score, fecal consistency, flock size, number of ewes and lambs in flock, pasture rotation and size, lambing period, access to surface water, contact with cattle, production type, geographical location, etc. Cryptosporidium oocyst and G. duodenalis cyst were detected and numbered in feces using a direct immune-fluorescent assay. DNA was extracted, and the SSU rRNA gene was amplified by nested PCR and sequenced for phylogenetic analysis and molecular characterization of a subset of 74 Cryptosporidium positive samples. The overall prevalence of Cryptosporidium was 30.6% in lambs, 16.1% in yearlings and 3.2% in adult ewes; peak prevalence was observed in two (37.4%) and three (38.3%) month old lambs. The prevalence of G. duodenalis was 48.1% in lambs, 45.1% in yearlings and 15.2% in adult ewes; peak prevalence was observed in four (83.3%) and five (76.9%) month old lambs. Based on an estimated fecal production of 2.5% body weight per day, the environmental loading rate of Cryptosporidium oocyst was estimated to range from 0.5 x106 to 6.8 x106 for lambs, from 2.9 x104 to 4.4 x104 for yearlings, and from 0.3 x106 to 1 x106 for ewes. The environmental loading rate of G. duodenalis cysts was estimated to range from 3 x106 to 34 x106 for lambs, from 16 x10 6 to 24 x106 for yearlings, and from 3 x106 to 8.7 x106 for ewes. Statistical analysis showed that access to drink surface water, and contact with cattle significantly increased the odds of Cryptosporidium shedding in sheep of all ages. Reduced odds of shedding Cryptosporidium was observed in lambs as the number of ewes increased in the flock and in adult ewes as the pasture size increased. In addition to drinking surface water, the odds of G. duodenalis also increased in sheep that were grazing on irrigated pastures. Ewes lambing in a pasture with access to a barn, and moving the newly born lamb with the ewe mother to a new and clean pasture after lambing presented reduced odds of shedding G. duodenalis in lambs and ewes. Diarrhea was not associated with Cryptosporidium or G. duodenalis shedding in sheep. Lower body condition scores were associated with G. duodenalis shedding in adult ewes. Cryptosporidium xiaoi was the most common species found in 89.2% (66/74) positive sheep samples evaluated. A subset of 6 samples were confirmed as C. xiaoi at the actin gene level. The zoonotic C. ubiquitum was found in 8 lambs, representing 11% (8/74) of the population evaluated. Cryptosporidium ubiquitum ubiquitum sequences were identical to isolates previously reported in human and sheep infections worldwide. The low prevalence of C. ubiquitum indicate that lambs can be considered a minor source of zoonotic Cryptosporidium in California.
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793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3565407