Multistate outbreak of human Salmonella typhimurium infections associated with aquatic frogs - United States, 2009. (1/7)

During April-July 2009, the Utah Department of Health identified five cases of Salmonella Typhimurium infection with indistinguishable pulsed-field gel electrophoresis (PFGE) patterns, predominantly among children. In August, CDC began a multistate outbreak investigation to determine the source of the infections. This report summarizes the results of this ongoing investigation, which, as of December 30, had identified 85 S. Typhimurium human isolates with the outbreak strain from 31 states. In a multistate case-control study, exposure to frogs was found to be significantly associated with illness (63% of cases versus 3% of controls; matched odds ratio [mOR] = 24.4). Among 14 case-patients who knew the type of frog, all had exposure to an exclusively aquatic frog species, the African dwarf frog. Environmental samples from aquariums containing aquatic frogs in four homes of case-patients yielded S. Typhimurium isolates matching the outbreak strain. Preliminary traceback information has indicated these frogs likely came from the same breeder in California. Reptiles (e.g., turtles) and amphibians (e.g., frogs) have long been recognized as Salmonella carriers, and three multistate outbreaks of human Salmonella infections associated with turtle contact have occurred since 2006. However, this is the first reported multistate outbreak of Salmonella infections associated with amphibians. Educational materials aimed at preventing salmonellosis from contact with reptiles should be expanded to include amphibians, such as aquatic frogs.  (+info)

Aquatic feeding in pipid frogs: the use of suction for prey capture. (2/7)

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Reversal to air-driven sound production revealed by a molecular phylogeny of tongueless frogs, family Pipidae. (3/7)

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Notes from the field: update on human Salmonella Typhimurium infections associated with aquatic frogs--United States, 2009-2011. (4/7)

CDC is collaborating with state and local public health departments in an ongoing investigation of human Salmonella Typhimurium infections associated with African dwarf frogs (ADFs). ADFs are aquatic frogs of the genus Hymenochirus commonly kept in home aquariums as pets. From April 1, 2009 to May 10, 2011, a total of 224 human infections with a unique strain of S. Typhimurium were reported from 42 states. The isolates are indistinguishable by pulsed-field gel electrophoresis and multiple-locus variable-number tandem repeat analysis. This outbreak likely includes considerably more than the 224 laboratory-confirmed cases reported to CDC; only an estimated 3% of Salmonella infections are laboratory confirmed and reported to surveillance systems. Surveillance for additional cases continues through PulseNet, the national molecular subtyping network for foodborne disease surveillance.  (+info)

The breathing pattern and the ventilatory response to aquatic and aerial hypoxia and hypercarbia in the frog Pipa carvalhoi. (5/7)

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US outbreak of human Salmonella infections associated with aquatic frogs, 2008-2011. (6/7)

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Dorsal mesoderm has a dual origin and forms by a novel mechanism in Hymenochirus, a relative of Xenopus. (7/7)

The dorsal mesoderm in the frog Hymenochirus forms by a mechanism not previously described in any other vertebrate. Unlike its close relative, Xenopus laevis, in which the mesoderm derives entirely from the deep mesenchymal cells of the marginal zone, Hymenochirus has "surface mesoderm" originating in the involuting marginal zone epithelium. Fluorescently labeled grafts show stage-specific invasion of deep axial tissue by cells originally located in the surface layer. These cells participate in normal mesoderm development. In video recordings, the labeled surface area shrinks as surface cells invade the deep layer. Furthermore, the mechanism of surface mesoderm morphogenesis differs from that described in other amphibians. Scanning electron microscopy at several neurula stages indicates that prospective somite cells do not individually detach from their epithelial neighbors to ingress into the deep layer, as seen in other amphibians; instead, their basal ends adhere to the somitic mesoderm as a coherent layer, taking on somitic morphology while still a part of the archenteron lining. This novel morphogenetic process we dub "relamination." Prospective notochord cells individually spread on the ventral surface of the notochord, gradually ingressing from their epithelial neighbors, but by a mechansism involving active pulling and spreading by their invasive basal ends rather than depending on apical constriction as do the corresponding "bottle cells" in other amphibians. Lateral endoderm migrates dorsally, replacing the relaminating surface mesoderm and fusing at the dorsal midline of the archenteron. These processes demonstrate the diversity of morphogenesis at the cellular, and presumably the molecular, level and shed light on the evolution of morphogenetic mechanisms.  (+info)