Fatal Infection in a Wild Sandbar Shark (Carcharhinus plumbeus), Caused by Streptococcus agalactiae, Type Ia-ST7

Abstract

Streptococcus agalactiae is one of the most important fish pathogenic bacteria as it is responsible for epizootic mortalities in both wild and farmed species. S. agalactiae is also known as a zoonotic agent. In July 2018, a stranded wild sandbar shark (Carcharhinus plumbeus), one of the most common shark species in the Mediterranean Sea, was found moribund on the seashore next to Netanya, Israel, and died a few hours later. A post-mortem examination, histopathology, classical bacteriology and advanced molecular techniques revealed a bacterial infection caused by S. agalactiae, type Ia-ST7. Available sequences publicly accessible databases and phylogenetic analysis suggest that the S. agalactiae isolated in this case is closely related to fish and human isolates. To the best of our knowledge, this is the first description of a fatal streptococcosis in sandbar sharks.

First Isolation and Characterization of Streptococcus agalactiae From a Stranded Wild Common Dolphin (Delphinus delphis)

“…Using the Genome Comparator (GC) tool, allelic profiles of the 2,207 loci were retrieved and imported to BioNumerics 8.0 (Applied Maths) in order to generate a phylogenetic tree (Figure 3). The present isolate is almost identical with a two-SNP difference in comparison of 1,969,033 bases (96.7% genome size), to an isolate described by Morick et al (2020), collected from a moribund sandbar shark (Carcharhinus plumbeus) found on Netanya's shoreline (Israeleast Mediterranean coast) in FIGURE 1 | Gross pathology of the urinary bladder of a common dolphin (Delphinus delphis). About five ml of mucopurulent discharge was observed in the urinary bladder.…”

“…Long-term monitoring should be done, and funds should be constantly allocated to better understand the demographic and evolutionary effects of infectious diseases (Vella et al, 2021), as well as the genetic basis of susceptibility. This pathogen has been diagnosed in other marine fish (Morick et al, 2020) and now in a marine mammal in the eastern Mediterranean Sea. Possible transmission routes of this pathogen into marine mammals can include infected prey, sea bird feces and human and terrestrial animals wastes via sewage and rivers (Numberger et al, 2021).…”

Global assessment of shark strandings

“…(Carnobacteriaceae), Streptococcus spp. (Streptococcaceae) or by the ciliated protozoan Miamiensis avidus (Parauronematidae) (Carlisle et al, 2015; Dagleish et al, 2010; Martinez‐Steele et al, 2018; Morick et al, 2020; Retallack et al, 2019; Schaffer et al, 2012, 2013). The genus Carnobacterium is part of the bacterial community in some teleost and sharks, but in cases of stress‐induced immunosuppression, these bacteria can become pathogenic leading to systemic infection and subsequent morbidity and mortality (Schaffer et al, 2013).…”

“…The genus Carnobacterium is part of the bacterial community in some teleost and sharks, but in cases of stress‐induced immunosuppression, these bacteria can become pathogenic leading to systemic infection and subsequent morbidity and mortality (Schaffer et al, 2013). As for Streptococcus spp., there is one report of a fatal infection in a sandbar shark ( Carcharhinus plumbeus , Carcharhinidae) stranded in Israel (Morick et al, 2020). The post ‐ mortem examination indicated meningoencephalitis caused by S .…”

“…However, in more serious cases or for largesized species, euthanasia may be necessary, emphasizing the need for trained professionals to respond to calls, as well as veterinarians/ veterinary pathologists and other experts to perform diagnostics. Miamiensis avidus (Parauronematidae) (Carlisle et al, 2015;Dagleish et al, 2010;Martinez-Steele et al, 2018;Morick et al, 2020;Retallack et al, 2019;Schaffer et al, 2012Schaffer et al, , 2013. The genus Carnobacterium is part of the bacterial community in some teleost and sharks, but in cases of stress-induced immunosuppression, these bacteria can become pathogenic leading to systemic infection and subsequent morbidity and mortality (Schaffer et al, 2013).…”