Wednesday, 7 October 2015

Article Analysis//Cryptosporidium

Just a fair warning... for those of you that don't appreciate stories of nasty bacterial and intestinal infections. This is an article analysis on an outbreak that happened earlier this year. I cut the abstract aaaaaand the pictures. (welcome)

Cryptosporidium: Evading the Nemesis
          Airplanes, Cruise ships. College dorms, recreational pools. People, public places, and the organisms that inhabit them sometimes cry mutiny against a healthy system wreaking havoc and ultimately causing distress. Cryptosporidiom muris, or ‘Crypto’ in short, is a single celled parasite most commonly known for causing Cryptosporidiosis, a diarrheal disease.
          The causal agent of Cryptosporidiosis is a protozoan, a parasitic oocyst. Route of infection most commonly includes contaminated drinking water (such as in third-world countries with poor water supplies), extensive and unprotected contact with livestock, especially bovines, and the occasional inhalation of an oocyte through the respiratory route. Once ingested, the oocyst becomes a sporozoite (spore releasing) and cycles between asexual (trophozooite or type I meronts) or sexual (merozooite or type II) reproduction in the gastrointestinal tract. In this tract, the parasite reproduces asexually (schizogony). Sexual reproduction for the parasite differs from asexual in that gametogony produces micro and macrogamonts (male and female, respectively).  The results of this cycle are two different oocysts, thick and thin-walled. The former is often excreted while the latter preoccupies itself with further infectious duties. Because excretion is the end of a cycle, the oocysts allows for infection directly after excretion (Parasites).
          Risk factors and sources of infection are important measures in infection prevention. Common sources of the parasite include food, water, or fomites (door knobs, tables, tools etc.) which have been contaminated by feces from infected sources. Risks range from direct contact (caring for an infected individual, contact with infected animals, changing diapers) to swimming in community pools, attending playgrounds, travelling, and many others. Public pools are especially dangerous if children are defecating or voiding within the pool, and recent outbreaks have been traced to this cause (Rettner). Sources of infection include but are in no way limited to handling livestock without proper protective measures (donning of gloves and boots, hand hygiene), campers or travelers drinking questionable water, working with children, and even self- infection (fecal oral route) if an individual is not taking care to wash their hands frequently (Parasites). 
          Though symptom intensity does vary between individuals (especially those with immunosuppression and HIV/AIDS), the common symptoms are watery stool followed by dehydration, nausea, vomiting, fever, and weight loss. Most often, the small intestine is affected by the parasite, but the respiratory tract can be subjected to infection if an oocyst is inhaled. Symptoms typically last a fortnight (Parasites). Crypto can be cured by auto-recovery, that is, most healthy immune systems will regain composure after infection; it is simply a case of letting the parasite run its course, per se. A supporting measure is to constantly drink fluids to replace water loss. For pregnant women, the fluid loss can be extremely detrimental, while for babies it can prove to be fatal. Additionally, those with HIV/AIDS should take even more measures to care for their health because most Crypto symptoms will not be visible because of the already compromised immune system.
          It was the beginning of the 2015 spring semester for veterinary medicine students in Philadelphia, Pennsylvania when the school’s health center was alerted to five cases of students with some type of gastrointestinal issue. Twenty-two students had been present at a bovine obstetrics training session, and five of these same twenty-two reported symptoms of cramps, nausea, vomiting, fever, and diarrhea (the nausea and vomiting, like intermittent symptoms of malaria are caused by release of merozooites after oocyte reproduction) CITE . After further interviews and research, a total of sixteen students (including the original five) had reported the said symptoms. With this factor in the equation, specimens from the calves the students worked with were collected and tested, and results of an acid-fast stain performed with a calf intestine smear tested positive for oocysts of Cryptosporidium. Though the protocol for PPE (personal protective equipment) was in place and all twenty-two students wore gloves, it is not known how many of the students were vigilant about their outerwear and hand hygiene.              
          Concerning the student demographic, thirteen of the twenty-two were female, sixteen symptomatic cases were reported. Of the sixteen reported cases, four symptomatic students submitted specimen samples for case confirmation. Interestingly, most cases were able to be classified as strict Crypto, just because of the basis of definitions provided by the Centers for Disease Control and Prevention. These cases were very obvious. Other testing used was direct fluorescent antibody testing in which a dye stains the antigen making it visible using microscopy. This testing determined the obstetrics lab as the source of the outbreak.
          This outbreak was undoubtedly dangerous, and it could have been avoided providing the students had followed the PPE protocol. Unfortunately, many people think that washing hands after using the bathroom or touching animals is enough; there is a reason why gloves and even coveralls paired with boots were called for in this obstetrics laboratory. I think it important that students in any science field follow protective measures implicitly. This does not mean no one should ever play in public pools, have a garden, or raise calves - my family does all of these and they are very rewarding. It does, however, mean increased attentiveness to hygiene. I have had family members go through this horrible infectious experience and it is something that could have been avoided; because of this, I advocate attentive precautions.
          Most often, ‘Crypto’ appears paired with a decreased vigilance in proper hygiene and or improper handling of either specimens or animals. The oocyst or the Cryptosporidium parasite “survives various environmental pressures, as low as -7.6 [degrees]F (-22[degrees]C) for >700 hours”(Drinkard). This is fascinating, the way these parasites seem to conquer their environment in order to survive. The survival of these parasites in such variant temperatures, however, should be a signal to those dealing with animals, whether in livestock or in veterinary science, that proper protection is never not effective, Just because we do not see a parasite does not indicate that it is not there. Such gastrointestinal distress can be avoided if the correct protective and preventative measures are applied.

Drinkard, L., et al. Outbreak of cryptosporidiosis among veterinary students – Philadeplphia,
Pennsylvania. Morbidity and Mortality Weekly Report, 64(28). 773.
Parasites, Cryptosporidium: Diagnosis, risk factors, illness, symptoms, and treatment. Centers
for Disease Control and Prevention. (2015, April 2). Retrieved Sept. 21, 2015.
Rettner, R. (2015). Crypto parasite outbreaks increasing pools across the US. LiveScience.

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