title: Mass mortality of adult male subantarctic fur seals: are alien mice the culprits?
abstract: BACKGROUND
  Mass mortalities of marine mammals due to infectious agents are increasingly reported. However, in contrast to previous die-offs, which were indiscriminate with respect to sex and age, here we report a land-based mass mortality of Subantarctic fur seals with apparent exclusivity to adult males. An infectious agent with a male-predilection is the most plausible explanation for this die-off. Although pathogens with gender-biased transmission and pathologies are unusual, rodents are known sources of male-biased infectious agents and the invasive Mus musculus house mouse, occurs in seal rookeries.
  
  
  RESULTS
  Molecular screening for male-biased pathogens in this potential rodent reservoir host revealed the absence of Cardiovirus and Leptospirosis genomes in heart and kidney samples, respectively, but identified a novel Streptococcus species with 30% prevalence in mouse kidneys.
  
  
  CONCLUSIONS
  Inter-species transmission through environmental contamination with this novel bacterium, whose congenerics display male-bias and have links to infirmity in seals and terrestrial mammals (including humans), highlights the need to further evaluate disease risks posed by alien invasive mice to native species, on this and other islands.
authors.affiliation: Mammal Research Institute, Department of Zoology & Entomology, University of Pretoria, Pretoria, South Africa. pjndebruyn@zoology.up.ac.za
authors.forename: P J Nico
authors.initials: PJ
authors.lastname: de Bruyn
authors.forename: Armanda D S
authors.initials: AD
authors.lastname: Bastos
authors.forename: Candice
authors.initials: C
authors.lastname: Eadie
authors.forename: Cheryl A
authors.initials: CA
authors.lastname: Tosh
authors.forename: Marthán N
authors.initials: MN
authors.lastname: Bester
mesh_terms: D000818:Animals; D017943:Cardiovirus / Q000235:genetics; D053476:Extinction, Biological; D005260:Female; D046069:Fur Seals / Q000502:physiology*; D007668:Kidney / Q000382:microbiology; D007922:Leptospirosis / Q000235:genetics; D008297:Male; D051379:Mice; D015995:Prevalence; D012737:Sex Factors; D013045:Species Specificity; D013290:Streptococcal Infections / Q000175:diagnosis / Q000382:microbiology; D013291:Streptococcus / Q000235:genetics / Q000378:metabolism