1) Describe an experiment of your design to build upon what was found in this st
ID: 95999 • Letter: 1
Question
1) Describe an experiment of your design to build upon what was found in this study (make sure it is clearly related to the specific findings in this article! You will lose points if it is not closely related to the topic at hand!).
2) Propose two changes you would have made to the experiments described in the article to strengthen THIS publication (these should be realistic changes to the research described, not an entirely different experiments – use that for question #1!)
MAJORARTICLE The First Association of a Primary Amebic Meningoencephalitis Death With Culturable Naegleria fowleri in Tap Water From a UsS Treated Public Drinking Water System Jennifer R. Cope, Raoult . Ratard Vincent R. Hill Theresa Sokol2 Jonathan Jake Causey2 Jonathan S. Yoder. Gayatri Mirani Bonnie Mul Kimberly A. Mukerjee,3 Jothikumar Narayanan Meggie Doucet,3 Yvonne Ovarnstrom,1 Charla N. Poole, Olugbenga A. Akingbola,3 Jana M. Ritter, Zhenggang Xiong. Alexandre J. da Silva, Dawn Roellig.1 Russell B. Van Dyke,3 Harlan Stern,3 Lihua Xiao, and Michael J. Beach Centers for Disease Control and Prevention, Atlanta, Georgia: Louisiana Department of Health and Hospitals, New Orleans and Baton Rouge, and Tulane University Health Sciences Center, New Orleans, Louisiana Background. Naegleria fowleri is a climate-sensitive, thermophilic ameba found in warm, freshwater lakes and rivers. Primary amebic meningoencephalitis (PAM), which is almost universally fatal, occurs when N. fowleri containing water enters the nose, typically during swimming, and migrates to the brain via the olfactory nerve. In August 2013, a 4-year-old boy died of meningoencephalitis of unknown etiology in a Louisiana hospital. Methods. Clinical and environmental testing and a case investigation were initiated to determine the cause of death and to identify potential exposures. Results. Based on testing of cerebrospinal fluid and brain specimens, the child was diagnosed with PAM. His only reported water exposure was tap water; in particular, tap water that was used to supply water to a lawn water slide on which the child had played extensively prior to becoming ill. Water samples were collected from both the home and the water distribution system that supplied the home and tested; N. fowleri was identified in water samples from both the home and the water distribution system. Conclusions. This case is the first reported PAM death associated with culturable N. fowleri in tap water from a US treated drinking water system. This case occurred in the context of an expanding geographic range for PAM beyond southern states, with recent case reports from Minnesota, Kansas, and Indiana. This case also highlights the role of adequate disinfection throughout drinking water distribution systems and the importance of maintaining vigilance when operating drinking water systems using source waters with elevated temperatures. Keywords. Naegleria fowleri; primary amebic meningoencephalitis; free-living ameba. Naegleria fowleri is a climate-sensitive, thermophilic, then migrates along the olfactory nerve through the free-living ameba found naturally in freshwater en cribriform plate to the brain. In the United States, up to ronments [1]. The disease, primary amebic meningoen- 8 cases are recognized each year [2].In US case patients, cephalitis (PAM), occurs when N. fowleri-containing infection occurs primarily in males and children at a water enters the nose, usually during swimming, and median age of 12 years [2]. Symptoms start an average of 5 days after exposure and are indistinguishable from those of bacterial meningitis [2]. Early on, symptoms in- clude fever, headache, nausea, and vomiting, progressing to altered mental status, seizures, and coma. Death typ- ically occurs within 5 days of symptom onset [2]. Most exposure to warm, un treated freshwater while participating in recreational water activities such as swimming and diving. Recently, Received 25 September 2014; accepted 24 December 2014: electronically pub- lished 16 January 2015 Correspondence: Jennifer R. Cope, MD, MPH, 1600 Clifton Rd NE, MS C-09, Atlanta, GA 30333 (bt9@dc.gov Clinical Infectious Diseases 2015,60(8ke36-4:2 Published by Oxford University Press on behalf of the Infectious Diseases Society of PAM cases are associated with Armerica 2015. This work is written by la) US Govemment employee(sl and is in the public domain in the US. DOl: 10.103/cid/ov07 :36 . CID 2015:60 (15 April) . Cope et alExplanation / Answer
1) Thanks to a recent study in 2014 by Denise C Zysset-Burri were pathogenicity factors from Naegleria fowleri were identified, a way more specific PCR assay than the ones performed in this paper. Samples will be grown in Nelson’s medium or PYNFH medium supplemented with liver hydrolysate (LH, PYNFH/LH medium) stimulates highly pathogenic N. fowleri. A TaqMan real-time PCR assay for Villin-1 gene will be performed as this protein is highly involved in N. fowleri pathogenicity.
2) Samples should have been kept in higher temperatures for shipping and not only at room temperature as warms stimulates N. fowleri growth. Also, the PCR assay done in this paper was is a technique developed to simultaneously detect three types of amoeba: Acanthamoeba spp., Balamuthia mandrillaris, and Naegleria fowleri, and being a TaqMan PCR the signals could have been from any of those two other amebae, thankfully a sequencing was done and two genotypes of N. fowleri were identified which supports their PCR findings. But a more specific PCR assay must be done, to detect only N. fowleri isolates that are highly pathogenic and in this way link the clinical samples with the environmental samples to prove they are the same isolates, as proposed in question one (PCR for protein villin-1)
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