The frequency of photosensitization in a dairy cattle herd infected by Leptospires

Document Type : Scientific report


Department of Clinical Sciences, School of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran


Leptospirosis is a bacterial zoonotic disease, which can induce hepatic lesions. Photosensitization (PS)
maybe is the result of accumulation of photodynamic agents in unpigmented area of the skin exposed to
sunlight which occurred due to hepatic lesions. An outbreak of leptospirosis was occurred in a dairy cattle
herd complex with 760 dairy milking cows in March (1990). Totally, 412 cows (54.21%) showed clinical
signs including fever, systemic mastitis, haemoglobinuria, jaundice, lameness, abortion and stillbirth. The
microscopic agglutination test (MAT) was used for diagnosis of leptospirosis. The herd was infected with
Leptospira interrogans grippotyphosa, L. interrogans icterohaemorrhagiae, L. interrogans pomona, L.
interrogans canicola and L. interrogans hardjo. Only one (0.13%) cow showed PS in the unpigmented skin
dorsum. MAT showed that she was infected with L. interrogans pomona, L. interrogans hardjo and L.
interrogans icterohaemorrhagiae with titre of 1 : 3200 of antibody. In spite of the high incidence of
leptospirosis, the frequency of PS was too low.