Case Report: Mass death of frogs (Rana dybowskii) caused by septicemia in artificial raising farm

Abstract

Frog culture industry is not yet familiar but has much potential. Generally, in farm, the population density is higher than that of in nature and frog farm is not the exception. But when population density is high, it can easily leads to stressful condition, poor sanitation. When a disease occur, it is a primary factor that makes the population more susceptible and the results more grave. Because of severe Rhabditoidea-helminth infection and subsequent bacterial septicemia, 50∼70% of the total population had been died in a farm in Jeong-sun in Gangwon-do and Chungju in Chungcheongbuk-do from late June, 2012 to September, 2012. Diseased frogs showed ruptured lung, bloody ascites, liver discoloration, myocardium weakness, congested kidney, microcytic anemia and so on. Enterobacteriacea, Citrobacter.sp, Cupriavidus metallidurans, Acinetobacter.sp were isolated as major bacterium that had caused septicemia in frogs. Among isolated bacterium, Cupriavidus metallidurans, Ewingella americana, Shewanella aquimarina and Pseudoalteromonas sp. have not reported as potential pathogens in frogs before. It is a good example that severe helminth infection in frogs can lead to secondary infection of bacteria.

Bacterial agents isolated from cultured marsh frog (Pelophylax ridibundus, Pallas 1771)

“…Aeromonads, natural members of the aquatic environment (Austin and Austin, 2007), have been reported in previous studies in various diseases of frogs, especially in cases of red-leg sydrome (Mauel et al, 2002;Huys et al, 2003;Pasteris et al, 2006;Lee et al, 2009). Previously, Citrobacter freundii was reported in gut microbiota of American bull frogs (Miles et al, 2004), internal organs of diseased Rana dybowskii (Jeong et al, 2014) and as agent of the red-leg sydrome (Pasteris et al, 2011). In this study, the presence of Citrobacter freundii in both frog and water samples indicates, that it can be an opportunistic pathogen for P. ridibundus.…”

“…In contrast, Schadich and Cole (2010) found that A. hydrophila/ caviae was harmless to Litoria ewingii. Although lack of serious findings of red-leg syndrome, previous reported etiologic agents like A. hydrophila (Pilarski and Schocken-Iturrino, 2010;Pasteris et al, 2011;Tee and Najiah, 2011;Jeong et al, 2014;Xiaoying et al, 2015), E. tarda, Chryseobacterium indolgenes, Pseudomonas spp. (Tee and Najiah, 2011) and K. pneumoniae (Schadich and Cole, 2010) were also identified in this study.…”

“…Thus, Acinetobacter sp. (Jeong et al, 2014), A. hydrophila/caviae (Mauel et al, 2002;Huys et al, 2003), Aeromonas sp. (Amborski et al, 1983), Chryseobacterium indologenes, Citrobacter braakii, E. tarda (Tee and Najiah, 2011), Enterobacter sp., E. coli (Pasteris et al, 2009) and Pseudomonas sp.…”

“…Stressed conditions like crowding or unsanitary lead to overcome weakened immune barriers and cause disease (Mauel et al, 2002). Causative agents of bacterial diseases in many frog species, both wild (Schadich and Cole, 2010) and cultivated (Amborski et al, 1983;Mauel et al, 2002;Huys et al, 2003;Pasteris et al, 2006;Pasteris et al, 2009;Pasteris et al, 2011;Pilarski & Schocken-Iturrino, 2011;Jeong et al, 2014;Xiaoying et al, 2015), and in water samples (Pasteris et al, 2006;Hacioglu et al, 2015) have been reported previously. However, as far as literature reviews are concerned, no reports about bacterial agents of marsh frogs have been found.…”