Percent mortality and infection among embryo, hatchling, larval, and metamorphosis developmental stages for <i>Lithobates sylvaticus</i>, <i>L. pipiens</i>, <i>L. clamitans</i>, <i>Anaxyrus americanus</i>, <i>Pseudacris feriarum</i>, <i>Hyla chrysoscelis</i>, and <i>Scaphiopus holbrookii</i>.

<p>Similar shaded bars with unlike letters are different (<i>P</i><0.006) by logistic regression analysis; <i>n</i> = 20 per developmental stage for each species.</p

Quantity of egg masses and collection sites in Tennessee and Pennsylvania, USA.

<p>Quantity of egg masses and collection sites in Tennessee and Pennsylvania, USA.</p

Infection of individuals exposed to ranavirus directly or indirectly.

<p>Infection prevalence between individuals exposed to ranavirus inoculum (direct) or via shedding (indirect) by a paired host. Treatments were paired individuals (<i>n</i> = 20 per bar) of different ectothermic vertebrate classes (A = amphibian, R = reptile, F = fish); thus, A|F = amphibian paired with fish. Infection of indirectly exposed individuals is evidence of waterborne transmission by directly exposed individuals.</p

Poor biosecurity could lead to disease outbreaks in animal populations - Fig 4

<p>Sections of liver from a control animal (A) and from ranavirus qPCR positive animals demonstrating ranaviral disease (B-D). (B) Necrosis of hematopoietic cells (arrows) and degeneration and necrosis of hepatocytes (arrowheads) in a liver from an amphibian co-housed for 60 minutes in a container where 40% of the amphibians were infected with ranavirus. (C) Diffuse necrosis of hematopoietic cells (arrows) and hepatocytes (arrowheads) in a liver from an amphibian processed in a simulated swabbing event where 10% of the amphibians were infected with ranavirus and gloves were not changed during processing. (D) Intracytoplasmic inclusion bodies (inset) and diffuse necrosis of hematopoietic cells and hepatocytes in a liver from an amphibian processed in a simulated swabbing event where 40% of the amphibians were infected with ranavirus and gloves were not changed during processing. Hematoxylin and Eosin stain. Bar equals 50 μm.</p

Survival functions for uninfected wood frog (<i>Lithobates sylvaticus</i>) tadpoles that were processed with and without changing gloves (yes, no) at two known ranavirus infection prevalence levels (10%, 40%).

<p>Survival functions for uninfected wood frog (<i>Lithobates sylvaticus</i>) tadpoles that were processed with and without changing gloves (yes, no) at two known ranavirus infection prevalence levels (10%, 40%).</p

Poor biosecurity could lead to disease outbreaks in animal populations

<div><p>Human-mediated disease outbreaks due to poor biosecurity practices when processing animals in wild populations have been suspected. We tested whether not changing nitrile gloves between processing wood frog (<i>Lithobates sylvaticus</i>) tadpoles and co-housing individuals increased pathogen transmission and subsequent diseased-induced mortality caused by the emerging pathogen, ranavirus. We found that not changing gloves between processing infected and uninfected tadpoles resulted in transmission of ranavirus and increased the risk of mortality of uninfected tadpoles by 30X. Co-housing tadpoles for only 15 minutes with 10% of individuals infected resulted in ranavirus transmission and 50% mortality of uninfected tadpoles. More extreme mortality was observed when the co-housing infection prevalence was >10%. Our results illustrate that human-induced disease outbreaks due to poor biosecurity practices are possible in wild animal populations.</p></div

The difference in the instantaneous rate of mortality (i.e., hazard ratio) for uninfected wood frog (<i>Lithobates sylvaticus</i>) tadpoles that were processed with and without changing gloves (yes vs. no) at two known ranavirus infection prevalence levels (10 vs. 40%).

<p>The difference in the instantaneous rate of mortality (i.e., hazard ratio) for uninfected wood frog (<i>Lithobates sylvaticus</i>) tadpoles that were processed with and without changing gloves (yes vs. no) at two known ranavirus infection prevalence levels (10 vs. 40%).</p

Survival functions for uninfected wood frog (<i>Lithobates sylvaticus</i>) tadpoles that were co-housed with infected tadpoles at three known ranavirus infection prevalence levels.

<p>Survival functions for uninfected wood frog (<i>Lithobates sylvaticus</i>) tadpoles that were co-housed with infected tadpoles at three known ranavirus infection prevalence levels.</p

Cycle threshold (CT) for qPCR on swabs taken from gloves at four known ranavirus prevalence levels after infected wood frog (<i>Lithobates sylvaticus</i>) tadpoles were processed.

<p>Low CT corresponds to higher viral load; different letters above boxes indicate significant differences by ANOVA and Tukey’s post-hoc comparison test.</p

The difference in the instantaneous rate of mortality (i.e., hazard ratio) for uninfected wood frog (<i>Lithobates sylvaticus</i>) tadpoles that were processed without changing gloves at four known ranavirus infection prevalence levels.

<p>The difference in the instantaneous rate of mortality (i.e., hazard ratio) for uninfected wood frog (<i>Lithobates sylvaticus</i>) tadpoles that were processed without changing gloves at four known ranavirus infection prevalence levels.</p