Not all hares die due to tularaemia

In November DWHC reported that tularaemia was found in the province of Overijssel and in the province of Limburg. Also in other parts of the Netherlands hare mortality was reported. It was questioned if the tularaemia was also the cause of death in those parts. In most cases there seems to be a different cause of death.

GMU Zenderen

At the time of the announcement of November (https://www.dwhc-dev.wp.hum.uu.nl/hazenpest-zenderen/ NL) about a hare with tularaemia in the area of the game management unit (GMU) Zenderen, three other submitted dead hares were still undiagnosed. Meanwhile it is clear that of these three hares, the first also had tularaemia, the second had the rabbit virus RHDV type-2, and the third hare had inflammations of which the causative agent couldn’t be detected (but tularaemia excluded).

Tularaemia

In 2018 tularaemia was so far found in the provinces of Utrecht (5), Overijssel (2) and Limburg (1). The positive hares from Utrecht were found dead earlier this year (February, August, and September). In former years this disease was also found in sick hares in Utrecht.

RHDV type-2

2017 was the first year in the Netherlands that rabbit virus RHDV type-2 was found in hares. This hare was from the region Aalten-Winterswijk. In addition to Gelderland, this virus was also detected in 2018 by hares from the provinces Overijssel and Noord-Brabant. RHDV type-2 belongs to the same virus group as the classic RHDV that caused mass mortality in rabbits in the 90’s. A few years ago, RHDV type-2 was first seen in wild rabbits in the Netherlands and has ever since caused death in rabbits.

EBHS

European Brown Hare Syndrome (EBHS) is caused by a virus that is closely connected to RHDV. This virus was first seen in Dutch hares in the 90’s. In former years EBHS was sporadically seen in hares that were submitted to DWHC. This year EBHS was already found in hares from the provinces of Friesland, Overijssel, and Gelderland.

Other causes of disease

In additon to these diseases there were also other causes of death, such as intestinal parasites, other bacteria, or trauma.