Causes of Mortality and Disease in Rabbits and Hares: A Retrospective Study

Abstract

In this study we determined the causes of mortality and disease in a total of 325 lagomorphs (rabbits and hares) in northern Spain between 2000 and 2018. Risk factors such as the species, age, sex, time of year and origin were also considered. Clinical signs, gross and histopathological findings and ancillary test results were the basis for the final diagnoses that were reviewed to classify and identify the different disorders. A total of 26 different conditions were identified. A single cause of death or illness was detected in 267 animals. They were grouped into parasitic conditions (n= 65; 24.34%) represented by encephalitozoonosis, hepatic coccidiosis, hepatoperitoneal cysticercosis, intestinal coccidiosis, parasitic gastritis and cutaneous ectoparasitosis; bacterial diseases (n = 56; 20.97%) including pseudotuberculosis, blue breast, skin abscesses, tularemia, pneumonic pasteurellosis and staphylococcal infections; nutritional and metabolic diseases (n = 48; 17.97%) with epizootic rabbit enteropathy, hepatic steatosis and pregnancy toxemia as prominent diseases; viral infections (n= 31; 11.61%) comprising rabbit hemorrhagic disease and myxomatosis and miscellaneous causes (n = 31; 11.61%) where rabbit enteritis complex, renal conditions (nephrosis), heat stroke, and arterial bone metaplasia were included; neoplasms (n = 12; 4.49%) represented by uterine adenocarcinoma, mammary adenocarcinoma, cutaneous fibroma, intestinal lymphoma and hepatic cholangiocarcinoma; toxicoses (n = 11; 4.11%); trauma-related injuries (n = 9; 3.37%) and finally congenital diseases (n = 4; 1.49%). In 58 animals of the study, some of these conditions were presented jointly. We discuss the detection frequency, possible causes or associated factors of the different pathologies as well as the importance of the different variables considered.

Zoonotic Microsporidia in Wild Lagomorphs in Southern Spain

“…Serological evidence of E. cuniculi exposure has also been detected in wild rabbits in other European countries, with seroprevalence values ranging between 3.9% in France and 44.7% in Slovakia [16,39]. The absence of E. cuniculi infection in Iberian hares in our study is in accordance with previous observations in other hare species [37,40]. Likewise, seroprevalence values found in European brown hares ranged between 0.0% in Italy and 2.9% in the Czech Republic [14,41].…”

“…In contrast, DNA of E. hellem was confirmed in the kidneys of a free-living European brown hare with chronic interstitial nephritis [17]. In addition, E. cuniculi infections have been confirmed in kidney and brain tissues of free-living Eastern cottontail rabbits [15] as well as in farmed and pet European rabbits [37,38]. Serological evidence of E. cuniculi exposure has also been detected in wild rabbits in other European countries, with seroprevalence values ranging between 3.9% in France and 44.7% in Slovakia [16,39].…”

Antibiotic removal does not affect cecal microbiota balance and productive parameters in LP robust rabbit line

“…Finally, regarding health status of the rabbits and diarrhea presence, significant differences were observed during the second week of the growing period, when the NoABs group showed a higher percentage of diarrhea and mortality rate, probably associated with the effects of rabbit epizootic enteropathy ( 48 , 49 ). This fact could be related to pathological disorders without a microbiota impact ( 50 ). However, it would be necessary to obtain global approaches to microbiability through the omic sciences (metagenomics, metabolomics, transcriptomics, genomics and epigenomics, etc.)…”

Surveillance of heat-related illness in small animals presenting to veterinary practices in the UK between 2013-2018.

“…Rabbits should be checked more frequently in hot weather to ensure animals can be cooled as soon as possible should HRI develop ( RAWF, 2017 ). The literature relating to HRI in rabbits is mostly limited to experimental models, but young male rabbits have reportedly been found dead due to acute “heat stroke” in Spain during the spring and summer months ( Espinosa et al, 2020 ). Rabbits are known to be susceptible to HRI due to having limited functional sweat glands and limited ability to disperse excess body temperature ( Elnagar, 2010 ).…”