The Water we drink |
Clinical Microbiology |
Presented to |
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They stared aimlessly out the window for the third day as the rain poured endlessly off the roof tops and onto the ground. They couldn’t help but to wonder if it would ever stop. Off in the distance they could see the pastures, that just three days before were over filled with cattle. Today no cattle could be seen because the lower pasture looked like a lake. Later that day the sun peaked out from behind the clouds and the rain slowed to a gentle pace. Excitement filled the air as it completely stopped and they once again could resume a life outside of the four walls they had been trapped in. They saddled the horses and took a ride to survey the pastures and check on the cattle. They stopped on the hillside looking over at the herd of five hundred cattle, all of which appeared to be standing side by side on what looked like the only dry ground left on the place and momentarily watched as the recent rain water rushed into the small now overfilled creek carrying away with it the 3 days of rain … and an intruder the whole town would come to know.
The intruder in the story is a parasite called cryptosporidium and it is believed to be transmitted from animals to humans through water that has washed across feces from animals that are infected with cryptosporidiosis. The water continues winding its way from the small overfilled creek to lakes, rivers and sometimes the public drinking water system. Depending on the temperature cryptosporidium can live a couple of days to a couple of months. Amazingly one cow can release ten to fifteen thousand spores in one bowel movement, when you look at a herd of 500 that’s a lot of spores of cryptosporidium looking for a new host to multiply in. Any animal or human that drink from or come in contact with that small little creek are inevitably going to get more than they bargained for.
According to an article on the waterborne pathogens website: one in five people can become infected with as little as ten spores.(Bukhari.et) Some people can be infected by as many as thirty spores before they show any evidence of being infected with cryptosporidiosis. It all just depends on the amount of exposure and the person’s immune system.
What is cryptosporidiosis you ask? It is an infection that starts off when a Cryptosporidium parasite is introduced to humans by the feces of infected animals generally through drinking water. However many outbreaks in the United States have occurred in waterparks, community swimming pools, and day care centers.(DPXd) Cryptosporidium can also be transferred from one person to another by kissing, sexual intercourse, or handling food before washing your hands. Cryptosporidium is spread in nosocomial settings such as hospitals, nursing homes, food service industries such as restaurants and occasionally from produce fresh out of the fields.
Although Cryptosporidium cannot reproduce outside of a host it is capable of multiplying itself in the epithelial lining of the gastrointestinal or the respiratory tract of animals and humans alike. Once a spore has found a suitable host; usually by ingestion and in rare instances by inhalation. The parasites outer shell will open up, much like an envelope and release four sporozytes. The sporozytes immediately take up residency in the mucosal lining of epithelial cells in the gastrointestinal or respiratory tract. Each sporozyte begins to duplicate itself. It then begins sexual reproduction, producing microgamonts (male) and macrogamonts (Female) which join to make two different types of oocytes. Thick walled oocytes exit the host through fecal matter and in rare instances by coughing or sneezing and then continue on to find another host to begin the cycle again. The thin walled oocytes are responsible for the symptoms exhibited from being