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Water-borne transmission of Cryptosporidium and Giardia in Belgium and Bangladesh

Md. Amimul Ehsan (2015)
abstract
Currently more than one billion people worldwide do not have access to safe drinking water or adequate sanitation. Important water-borne diarrhoeal diseases include cryptosporidiosis and giardiosis. Both in developed and developing countries, Cryptosporidium and Giardia are important causes of diarrhoea. This thesis aimed at studying (water-borne) transmission of Cryptosporidium and Giardia in Belgium and in Bangladesh. The literature review (chapter 1) starts with introducing Cryptosporidium and Giardia, followed by an overview of their prevalence and clinical importance in both human and animals. Then the different transmission cycles of both parasites are discussed, including water-borne transmission through drinking water and recreational water. Finally, different methods for detecting and quantifying Cryptosporidium and Giardia in water are described. In chapter 2, we monitored the presence of Cryptosporidium and Giardia in four drinking water catchment sites in Belgium. An attempt was made to determine the origin of (oo)cysts applying molecular tools. No contamination was found in purified drinking water at any site. In three catchments (Zillebeke, Gavers and Dikkebus), only low numbers of (oo)cysts were recovered from raw water samples. However, raw water samples from the Blankaart catchment site were frequently contaminated with Cryptosporidium and Giardia, especially in winter and spring. C. andersoni, C. suis, C. horse genotype, C. parvum and C. hominis and Giardia duodenalis assemblage AI, AII, BIV, BIV-like and E were identified. The genotyping results suggest that agriculture may be a more important source of surface water contamination than human waste in this catchment. Continuous monitoring of treated water for the presence of Cryptosporidium and Giardia would be justified and (point) sources of surface water contamination should be identified. In chapter 3, the infection risk of Cryptosporidium and Giardia in recreational waters in Belgium was assessed in swimming pools, recreational lakes, splash parks and water fountains. The risk of Giardia infection in the swimming pools varied from 1.13x10-6 to 2.49x10-6 per swim per person. In recreational lakes the estimated infection risk varied from 2.79x10-5 to 5.74x10-5 per swim per person for Cryptosporidium and from 7.04x10-5 to 1.46 x10-4 for Giardia and for other outdoor water recreation activities the estimated infection risk was 5.71x10-6 for Cryptosporidium and 1.47x10-5 for Giardia. However, given that mainly animal-associated species/genotypes were identified and that the (oo)cyst viability was not assessed, the infection risk associated with recreational lakes may be overestimated. No Cryptosporidium was found in splash parks and water fountains, but the presence of Giardia cysts suggests a risk for human infection. In chapter 4, we assessed the zoonotic and water-borne transmission of Cryptosporidium and Giardia in rural Bangladesh. High prevalences of Cryptosporidium and Giardia were found in both calves and their handlers, but genotyping results indicated that there was no zoonotic transmission between these two host populations. During monthly sampling of two village water ponds for two years, Cryptosporidium and Giardia were detected in 14/24 and 12/24 water samples respectively. Although the presence of Cryptosporidium and Giardia in both water ponds suggests that water-borne transmission of Cryptosporidium and Giardia is possible, genotyping results from infected village inhabitants and their cattle suggested no significant direct or indirect (water-borne) transmission of Giardia between cattle and people in this area of rural Bangladesh. In chapter 5, we provided recommendations for water companies and outlined future studies on water-borne transmission both in Belgium and in Bangladesh.
Please use this url to cite or link to this publication:
author
promoter
UGent, UGent and Muzahed Uddin Ahmed
organization
year
type
dissertation
publication status
published
subject
keyword
Cryptosporidium, water-borne, Giardia, Belgium, Bangladesh
pages
193 pages
publisher
Ghent University. Faculty of Veterinary Medicine
place of publication
Merelbeke, Belgium
defense location
Merelbeke : Faculteit Diergeneeskunde (auditorium D)
defense date
2015-06-05 16:30
ISBN
9789058644268
project
FWO
language
English
UGent publication?
yes
classification
D1
copyright statement
I have transferred the copyright for this publication to the publisher
id
6536637
handle
http://hdl.handle.net/1854/LU-6536637
date created
2015-06-15 14:11:21
date last changed
2018-06-08 06:28:09
@phdthesis{6536637,
  abstract     = {Currently more than one billion people worldwide do not have access to safe drinking water or adequate sanitation. Important water-borne diarrhoeal diseases include cryptosporidiosis and giardiosis. Both in developed and developing countries, Cryptosporidium and Giardia are important causes of diarrhoea. This thesis aimed at studying (water-borne) transmission of Cryptosporidium and Giardia in Belgium and in Bangladesh.
The literature review (chapter 1) starts with introducing Cryptosporidium and Giardia, followed by an overview of their prevalence and clinical importance in both human and animals. Then the different transmission cycles of both parasites are discussed, including water-borne transmission through drinking water and recreational water. Finally, different methods for detecting and quantifying Cryptosporidium and Giardia in water are described.
In chapter 2, we monitored the presence of Cryptosporidium and Giardia in four drinking water catchment sites in Belgium. An attempt was made to determine the origin of (oo)cysts applying molecular tools. No contamination was found in purified drinking water at any site. In three catchments (Zillebeke, Gavers and Dikkebus), only low numbers of (oo)cysts were recovered from raw water samples. However, raw water samples from the Blankaart catchment site were frequently contaminated with Cryptosporidium and Giardia, especially in winter and spring. C. andersoni, C. suis, C. horse genotype, C. parvum and C. hominis and Giardia duodenalis assemblage AI, AII, BIV, BIV-like and E were identified. The genotyping results suggest that agriculture may be a more important source of surface water contamination than human waste in this catchment. Continuous monitoring of treated water for the presence of Cryptosporidium and Giardia would be justified and (point) sources of surface water contamination should be identified.
In chapter 3, the infection risk of Cryptosporidium and Giardia in recreational waters in Belgium was assessed in swimming pools, recreational lakes, splash parks and water fountains. The risk of Giardia infection in the swimming pools varied from 1.13x10-6 to 2.49x10-6 per swim per person. In recreational lakes the estimated infection risk varied from 2.79x10-5 to 5.74x10-5 per swim per person for Cryptosporidium and from 7.04x10-5 to 1.46 x10-4 for Giardia and for other outdoor water recreation activities the estimated infection risk was 5.71x10-6 for Cryptosporidium and 1.47x10-5 for Giardia. However, given that mainly animal-associated species/genotypes were identified and that the (oo)cyst viability was not assessed, the infection risk associated with recreational lakes may be overestimated. No Cryptosporidium was found in splash parks and water fountains, but the presence of Giardia cysts suggests a risk for human infection.
In chapter 4, we assessed the zoonotic and water-borne transmission of Cryptosporidium and Giardia in rural Bangladesh. High prevalences of Cryptosporidium and Giardia were found in both calves and their handlers, but genotyping results indicated that there was no zoonotic transmission between these two host populations. During monthly sampling of two village water ponds for two years, Cryptosporidium and Giardia were detected in 14/24 and 12/24 water samples respectively. Although the presence of Cryptosporidium and Giardia in both water ponds suggests that water-borne transmission of Cryptosporidium and Giardia is possible, genotyping results from infected village inhabitants and their cattle suggested no significant direct or indirect (water-borne) transmission of Giardia between cattle and people in this area of rural Bangladesh.
In chapter 5, we provided recommendations for water companies and outlined future studies on water-borne transmission both in Belgium and in Bangladesh.},
  author       = {Ehsan, Md. Amimul},
  isbn         = {9789058644268},
  keyword      = {Cryptosporidium,water-borne,Giardia,Belgium,Bangladesh},
  language     = {eng},
  pages        = {193},
  publisher    = {Ghent University. Faculty of Veterinary Medicine},
  school       = {Ghent University},
  title        = {Water-borne transmission of Cryptosporidium and Giardia in Belgium and Bangladesh},
  year         = {2015},
}

Chicago
Ehsan, Md. Amimul. 2015. “Water-borne Transmission of Cryptosporidium and Giardia in Belgium and Bangladesh”. Merelbeke, Belgium: Ghent University. Faculty of Veterinary Medicine.
APA
Ehsan, M. A. (2015). Water-borne transmission of Cryptosporidium and Giardia in Belgium and Bangladesh. Ghent University. Faculty of Veterinary Medicine, Merelbeke, Belgium.
Vancouver
1.
Ehsan MA. Water-borne transmission of Cryptosporidium and Giardia in Belgium and Bangladesh. [Merelbeke, Belgium]: Ghent University. Faculty of Veterinary Medicine; 2015.
MLA
Ehsan, Md. Amimul. “Water-borne Transmission of Cryptosporidium and Giardia in Belgium and Bangladesh.” 2015 : n. pag. Print.