Tolio: Foot Rot in Grand Canyon River Runners.

Treating skin disorders in wilderness settings is often challenging. In this report we describe common skin conditions affecting the feet of river runners on the Colorado River in Grand Canyon National Park. These conditions are frequently referred to by river runners with a catchall term, "tolio." Several skin disorders have been identified as components of tolio, with the most prevalent currently being pitted keratolysis. We present a case of pitted keratolysis in a river guide occurring during a multiday river trip, where treatment can be difficult. Prevention is often more important.

Phylogenetic Analysis of Francisella tularensis Group A.II Isolates from 5 Patients with Tularemia, Arizona, USA, 2015-2017.

We examined 5 tularemia cases in Arizona, USA, during 2015-2017. All were caused by Francisella tularensis group A.II. Genetically similar isolates were found across large spatial and temporal distances, suggesting that group A.II strains are dispersed across long distances by wind and exhibit low replication rates in the environment.

Where Are the Ticks? Solving the Mystery of a Tickborne Relapsing Fever Outbreak at a Youth Camp.

During the summer of 2014 an outbreak of tickborne relapsing fever (TBRF) occurred in a group of high school students and staff at a youth camp, which was reported to Coconino County Public Health Services District. Six confirmed and five probable cases of TBRF occurred. During the environmental investigation two rodents tested positive for TBRF, but the vector, soft ticks, could not be found in their "normal" habitat. Ticks were finally located in areas not typical for soft ticks.

Norovirus Outbreaks Among Colorado River Rafters in the Grand Canyon, Summer 2012.

OBJECTIVE: To investigate the incidence and causative agent of the recurrent outbreaks of acute gastrointestinal illness (AGI) among different rafting groups on the Colorado River in the Grand Canyon National Park during the 2012 summer season. METHODS: Confidential illness reports were completed by all individuals with symptoms of AGI, and samples of fecal matter and vomitus, surface swabs of rafting equipment, and environmental swabs at stops along the hiking corridor were collected and tested for the presence of norovirus using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). RESULTS: During the active outbreak period between May 9 and July 9, 2012, 97 rafters (1.4%) from 10 trips (2.9% of all trips) declared AGI symptoms. AGI incidence within the 10 infected trips varied from 6% to 88%. Outbreaks occurred in 3 distinct temporal clusters that involved 2 different genogroups of norovirus. All available toilet fecal samples (5 samples) were positive for norovirus RNA: 1 with genogroup I (GI) and 4 with GII. The vomitus sample tested positive for GI. None of the fomite samples from rafting equipment or from the hiking corridors were confirmed for norovirus. CONCLUSIONS: The results suggest that norovirus may have been introduced by ill or asymptomatic individuals actively shedding the virus in their vomitus or feces, and spread within, or between, river trips by different modes of transmission. This study reinforces the importance of appropriate guidance and practice regarding norovirus prevention and the necessity of postoutbreak containment in relatively isolated groups of individuals.

Outbreak of norovirus illness in a college summer camp: impact of cleaning on occurrence of norovirus on fomites.

During the summer of 2005 an outbreak of norovirus acute gastroenteritis occurred in a residential college summer camp and was reported to the local health department. The outbreak spread rapidly to several other groups concurrently sharing the same facilities. During the investigation, fomites were sampled at different times in dorm rooms and tested for norovirus. The number of norovirus-positive rooms increased after the first room cleaning, from 40% to 73%. After the initial cleaning, the staff was instructed on proper cleaning and disinfection procedures and provided with disposable disinfecting wipes to reduce cross contamination, and the number of norovirus-positive rooms decreased to 30%. These findings reinforce the need for appropriate cleaning and disinfection procedures during a norovirus outbreak.

Genetic Analysis of Norovirus Strains that Caused Gastroenteritis Outbreaks Among River Rafters in the Grand Canyon, Arizona.

Toilet solid waste samples collected from five outbreaks among rafters in the Grand Canyon were subjected to sequencing analysis of norovirus partial capsid gene. The results revealed that a GI.3 strain was associated with one outbreak, whereas the other outbreaks were caused by GII.5 whose sequences shared >98.9% homology.

An analysis of water quality in the Colorado River, 2003-04; an investigation into recurring outbreaks of norovirus among rafters.

BACKGROUND: Every year over 22 000 people raft the Colorado River through the Grand Canyon in Arizona. Since 1994, over 400 rafters in 6 separate outbreaks have become ill with norovirus while rafting this stretch of the river. OBJECTIVES: To assess potential causes of these outbreaks, Colorado River water, water from nearby wastewater treatment plants, and a drinking water source were sampled and tested for norovirus and other water quality indicators. METHODS: Colorado River water was collected and sampled during the 2004 rafting season. Water from wastewater treatment plants near the Lee's Ferry launch site and drinking water from the Lee's Ferry launch site were also examined during the 2003 and 2004 rafting seasons. Stool samples from ill rafters and composite stool samples from onboard toilet-cans were tested for the presence of norovirus during the 2003 and 2004 outbreaks. Parameters examined included the following: norovirus by reverse transcriptase- polymerase chain reaction, coliforms, Escherichia coli, temperature, turbidity, and pH. RESULTS: No norovirus was detected in the Colorado River during the 2004 field sampling. Norovirus was detected in the Glen Canyon Dam Wastewater Treatment Plant on one occasion in 2004. Drinking water from the Lee's Ferry launch site was negative for norovirus in 2003, and Colorado River water from the Lee's Ferry launch site was negative for norovirus in 2004. In 2003, 3 of 10 stool samples from ill rafters or onboard toilet-cans were positive for norovirus. Neither of 2 stool samples collected in 2004 was positive for norovirus. CONCLUSIONS: Colorado River water tested during nonoutbreak periods was negative for norovirus, indicating that there is not an ongoing high level of norovirus contamination in the river. No source or sources of contamination could be identified from the testing. Potential sources of norovirus outbreaks among rafters include drinking contaminated river water, consuming contaminated foodstuff, rafter importation of the virus and subsequent person-to-person spread, and contaminated fomites, campsites, or equipment. It is likely outbreaks are the result of more than one source of norovirus, and the exact source remains unknown for several outbreaks.

Role of fomite contamination during an outbreak of norovirus on houseboats.

An outbreak of suspected norovirus gastroenteritis among three consecutive groups of houseboaters on a large recreational lake in Arizona was investigated to assess the role of fomite contamination, and to provide recommendations for prevention of future outbreaks. Interior boat surfaces were sampled for norovirus using transport swabs. Onboard toilet reservoirs were swabbed as a surrogate for stool samples from ill participants, since none were available, and onboard potable water supplies were sampled for norovirus. All samples were analyzed using RT-PCR with primers specific for human norovirus. Widespread fomite contamination was documented in the houseboats; 83% (5/6) of bathroom surface samples, 40% (2/5) of kitchen surface samples, and 100% (3/3) of doorknob samples were positive for the presence of norovirus. Samples of onboard potable water supplies were all negative. One of the participants on the first boating trip arrived already displaying symptoms of gastrointestinal illness prior to boarding the boat. This investigation demonstrates the potential role of widespread fomite contamination in outbreaks in confined spaces. To prevent or minimize future outbreaks in confined spaces, the adoption of practices such as surface disinfection and the utilization of methods to identify and exclude those with gastroenteritis from trips or activities in confined spaces, where others may become infected, are recommended.