Another study in 2000 using 18 Caspian seal corpses found several concurrent bacterial infections that could have contributed to the illness of the affected seals. These include "Bordetella bronchiseptica", "Streptococcus phocae", "Salmonella dublin", and "S. choleraesuis". "Corynebacterium caspium", a new bacterium, was identified in one of the seals, and poxvirus, "Atopobacter phocae", "Eimeria"- and "Sarcocystis"-like organisms, and a "Halarachne" species were identified in Caspian seals for the first time. The study also asserts that the “unusually mild” winter that preceded the die-off in 2000 could have contributed to its cause “through increased ambient air pressure and accelerated disappearance of ice cover at the breeding areas in the northern Caspian Sea.”