Wasps are the cause of an increasing mastitis problem in dairy cattle in Israel.

The German wasp Vespula germanica (Fabr.) (Hymenoptera: Vespidae) has been observed to injure dairy cows teats, causing lesions which can lead to mastitis. The number of dairy herds in Israel reported to be affected in this way has increased from five prior to 1989 to 32 from 1989 to 1993. Likewise, the geographical distribution of the colonies of these wasps has expanded from the Galilee to the northern Negev. Most cases of mastitis appeared during August and September when the wasps were most active; the predominant organism isolated was Streptococcus dysgalactiae. Apparently the wasps served as a vector in spreading S. dysgalactiae infection in the herds. More adult cows than first-calving cows were affected. The teats of the front quarters were more affected than those of the hind quarters.