[The incidence and seasonal dynamics of yersinioses (Y. pseudotuberculosis, Y. enterocolitica), staphylococcoses and pasteurelloses in hares from 1976 to 1982].

In the years 1976-1982, 2071 dead hares from 64 districts of the Czech Socialist Republic were examined. The diseases under study killed 400 hares (19.3%). Pseudotuberculosis which killed 210 hares (10.14%) from 46 districts of the Czech Socialist Republic (71.9%) is considered as the most important hare population regulator. The highest occurrence of diseases was recorded in 1978. Pseudotuberculosis was of seasonal nature with the highest incidence in November and December. The second most widespread disease was pasteurellosis which killed 126 hares (6.08%) from 36 districts of the Czech Socialist Republic (56.3%). This disease dominated in 1976 and occurred seasonally, the highest incidence being recorded in autumn (November), winter (January) and spring (March). The infections induced by the bacteria Yersinia enterocolitica were not very widespread and killed 32 hares (1.45%) from 20 districts of the Czech Socialist Republic (31.3%). The highest number of cases was recorded in 1977. The monthly pattern of the development of the disease had three peaks - in November, January and April. Staphylococcosis killed 32 hares (1.54%) from 14 districts in the Czech Socialist Republic (21.9%). The highest number of cases was recorded in 1976. The disease occurred throughout the year with the highest incidence in November, April and February. This seasonal dynamics correlated positively with the worsened natural conditions for hare's life and with the reduction of the natural resistance of their organisms. A particular negative influence was exerted by bad climatic and food conditions, and by the monodietary type of nutrition in the autumn fasting period. The disease occurrence was also examined in relation to the animals' age; besides the infections with the Y. enterocolitica bacteria, the diseases prevailed in the adult individuals, which was partly due to the higher proportion of adult animals among the hares investigated.