Massive Mortality of Common Carp (Cyprinus carpio carpio) in the St. Lawrence River in 2001: Diagnostic Investigation and Experimental Induction of Lymphocytic Encephalitis

Abstract

A massive fish kill affecting exclusively common carp (Cyprinus carpio carpio) in the St. Lawrence River, Québec, Canada, during the summer of 2001 was investigated by use of laboratory diagnostic methods and by an attempt to experimentally induce the disease. The ultimate causes of mortality were opportunistic bacterial infections with Aeromonas hydrophila and Flavobacterium sp. secondary to immunosuppression induced by physiologic (i.e., spawning) and environmental (i.e., high temperatures and low water levels) stressors, and possibly enhanced by an infection causing lymphocytic encephalitis observed in 9 of 18 (50%) fish examined. Experimental induction of disease was attempted in captured wild carp by administration of crude and filtered (particulate <0.22 microm) inocula prepared from a homogenate of tissues from carp affected by the natural outbreak. Although significant clinical disease or mortality was not induced by experimental challenge, lymphocytic encephalitis similar to the one observed in naturally affected carp was induced in four of seven (57%) fish administered crude inoculum and four of seven (57%) fish administered filtered inoculum. None of the control fish inoculated with sterile phosphate-buffered saline (n = 6) were affected by encephalitis. The cause of the encephalitis observed in carp from the natural outbreak and in experimentally inoculated fish could not be determined by use of virus isolation and transmission electron microscopy.

Characterization of an Actin-targeting ADP-ribosyltransferase from Aeromonas hydrophila

“…A pathogenic organism found ubiquitously in aquatic environments such as A. hydrophila could readily become a serious human health concern, in addition to its known reputation as a problem in the fish industry (51). Information gleaned from the aftermath of hurricane Katrina (52) and studies of drinking water distribution systems (53) further emphasizes that the health threats of A. hydrophila are real.…”

Hematological responses of tambaqui Colossoma macropomum (Serrassalmidae) fed with diets supplemented with essential oil from Mentha piperita (Lamiaceae) and challenged with Aeromonas hydrophila

“…Aeromonas hydrophila is among the pathogenic bacteria that have been correlated with high levels of fish mortality, on fish farms throughout the world over the last decade, thus resulting in huge economic losses (Monette et al 2006). This bacterium is frequently associated with hemorrhagic septicemia, fin erosion and abdominal cavity distension, among other pathological conditions (Paniagua et al 1990;Joseph and Carnahan 1994;Silva et al 2012).…”

Aeromonas spp. simultaneously harbouring blaCTX-M-15, blaSHV-12, blaPER-1 and blaFOX-2, in wild-growing Mediterranean mussel (Mytilus galloprovincialis) from Adriatic Sea, Croatia

“…Some members, such as Aeromonas hydrophila, Aeromonas veronii and, in particular, Aeromonas salmonicida, are causative agents of fish diseases that can lead to great economical losses in fishing industry (Janda and Abbott, 2010;Monette et al, 2006). In humans, aeromonads are opportunistic pathogens responsible for a variety of clinical syndromes, from gastroenteritis to life-threatening conditions such as septicemia and meningitis (Lamy et al, 2009).…”