Cryptosporidium in Drinking Water
Racheal Nell
Title: Cryptosporidium spp. in Drinking Water: Samples from rural sites in Switzerland
Introduction: Cryptosporidium is a coccidian parasite that infects the intestine of warm blooded
animals and humans. Crypto's life cycle first starts in contaminated matter, Crypto then feeds off
of the fecal matter and waits for the next host. They can survive several months without a host, a
host is infected orally threw direct fecal contact or contaminated food and water. Once they are
directly put into the stomach. Most parasites would be killed by the toxic acids found in
mammal’s stomachs but Crypto's niche of having a protective double layer oocysts around it.
Crypto is then passes through the stomach into the intestine. In the intestine Crypto latches on to
the intestinal lining and the new Crypto sporozoites is released. The sporozoites then invade the
epithelial cells and start to reproduce asexually or sexually within the cell. Once the epithelial
cell is full of sporozoites the cell wall breaks and they are released into the intestine. They then
try to reattach themselves to the lining or is released from the host and the cycle continues.
When infected the host will experience symptoms 1-14 days after being infected. severe
diarrhea, dehydration, cramps, fever and nausea are some of the common symptoms that lead
into weight loss and in some extreme cases death.
Reason for research: In 1995 a Cryptosporidium outbreak occurred in Milwaukee Japan,
infecting 15,000-400,000 people. Soon after this outbreak multiple investigations developed to
find the source of the contamination. It was concluded that the source of the infection was from
drinking water that was contaminated with fecal material. Nowadays, we have developed
regulations to keep Crypto under control reducing the infection rate to 1 for every 10,000. In
Switzerland, the drinking water distribution system include and extra treatment to insure the
water in Crypto free. However, in the rural areas of Switzerland the water is often in contact with
grazing animal's excrement and feces. The water is rarely treated but depended on for
consumption, the aim of this study was to see what the risk of infection would be through
consumption of the rural drinking water.
Method & Materials: Three samples of water (100mL) was taken from three different locations
of rural areas, site A- Alpine Village, Site B- Alpine Camp and Site C Mittelland town in
Switzerland at three different times. The samples were then transferred to a lab and tested for
Cryptosporidium spp and E.coli. For detection of the Crypto, the oocysts were stained with
specific surface antibodies and then looked at one by one through fluorescence microscopy. The
oocysts were then suspended my lysed open for DNA extraction. The DNA extraction was then
used for PCR and sequencing of the PCR products for further genotyping. The PCR products
were then put through sequence alignments for phylogenic analysis.
Results: The 18SrRNA gene of Crypto sp. was collected from a water sample at site A and
deposited into GenBank. At Site A, all three samples were contaminated with both Crypto and
E.coli. At site B the samples varied and had the highest concentration of oocyst after a heavy
rainfall. At Site C only one sample had an elevated oocyst concentration.
Discussion/Conclusion: After the experiment it was determined that the concentrations of the
oocyst present in the total water samples could be the direct source of the outbreak in the
children. They found a direct correlation with the amount of E.coli and Crypto, the greater
concentration of E.coli increased the concentration of Crypto oocsyt. Verifying that the
contamination could be coming from the fecal matter from all of the cattle and land animals.
When the heavy rain fell they noticed a great increase of concentration of oocyst, the soil better
infiltrates the manure during the heavy rainfall but on dry land the manure stays on the surface of
the soil.
Bibliography: http://www.ncbi.nlm.nih.gov/pubmed/23037557