8/7/2019 Lab Report Shellfish

1/3

Polytechnic University of the Philippines

College of Science, Department of Biology

Sta. Mesa, Manila

Mary Grace Abracia

BS Biology 4-2

Detection of Cryptosporidium sp. and Giardia sp. fromCommercial Bivalve Shellfish ( Perna viridis)

I. Introduction

Cryptosporidium spp. aremonoxenous protozoan parasitesthat cause gastrointestinaldiseases in humans and animals.Shellfish harvesting areas canbecome contaminated by theinfectious stage of the parasite andhumans are therefore at risk of infection either by consumption of shellfish, or by taking part inrecreational activities in theseareas.

Transmission of Cryptosporidium spp. occursmainly by ingestion of oocystseither by fecal-oral contact orthrough contaminated food ordrinking water. Localized epidemicsof food-borne cryptosporidiosishave been associated withuncooked sausage, offal, raw milk,apple cider, or foodstuffs, butwaterborne transmission seems toplay a more prominent role and isimplicated in most outbreaks of human cryptosporidiosis. Thepresence of Cryptosporidiumoocysts in drinking water supplies

has been well documented since1984, and waterborne epidemics of cryptosporidiosis have beenreported frequently in the UnitedStates, United Kingdom, and Japan,among other countries. Thepotential for water contaminationby cryptosporidial oocysts is high inareas where dumping of rawsewage is a common practice . Inaddition, the presence of waterborne Cryptosporidium spp.oocysts of animal origin needs tobe considered, since a singleneonatal ruminant can shed up to1010 oocysts during the course of infection . The presence of oocystsin river waters may also be asource of contamination of themarine environment. Riverspolluted by anthropogenic andlivestock fecal discharges could

play a major role in contaminationby oocysts of shellfish in estuariesand coastal environments.

The study was conducted todetermine the potential role of mussels ( Perna viridis ) asreservoirs of Cryptosporidium spp.

8/7/2019 Lab Report Shellfish

2/3

8/7/2019 Lab Report Shellfish

3/3

1 4.96 2.38 1.31 6.692 4.9 2.2 1.68 5.263 5.9 2.62 1.9 10.154 5.06 2.4 1.7 9.045 4.96 2.3 1.6 8.04

6 5.1 2.38 1.7 7.917 5 2.2 1.7 4.78 5 2.4 1.69 5.759 5.1 2.3 1.8 6.15

10 5.36 2.38 1.7 6.69Avera

ge5.134 2.356 1.678 7.038

*L-length: W- width, H-height; WT-Weight

IV. ConclusionThe mussle in the area of themarket of Sta.Mesa was notinfected of the parasiteCryptosporidium spp. and Giardiasp.

References

Gmez-Couso, H., F. Freire-Santos,C. F. L.

Amar, K. A. Grant, K. Williamson,M. E.

Ares-Mazs and J. McLauchlin2003.

Detection of Cryptosporidiumand

Giardia in molluscan shellfish by

multiplexed nested-PCR

Norling, P., and N. Kautsky 2007.Patches of

the mussel Mytilus sp. areislands of

high biodiversity in subtidalsediment

habitats in the Baltic Sea

Shields, J.M, E.R. Gleim, and M.J.Beach

2005. Prevalence of Cryptosporidium

spp. and Giardia intestinalis in

Swimming Pools, Atlanta,Georgia