Sarcocystis cruzi and Neospora caninum infection in cattle from Buenos Aires, Argentina

MORÉ G.; VENTURINI L.; VENTURINI M.C.; BASSO W.; BACIGALUPE D.

Christchurch, Nueva Zelanda.

Congreso; The 20th International Conference of the World Association for the Advancement of Veterinary Parasitology ( WAAVP); 2005

Studies were conducted for the detection of infections by Sarcocystis sp and Neospora caninum in cattle from Buenos Aires, Argentina.Thirty samples of  heart, diaphragm, oesophagus and blood were taken in 2 slaughterhouses, from each of three classes of cattle (total 90 animals). Classes were, according to age: class  A  (CA) 14-16 month(m), class B (CB) 24-30 m and class C (CC)42-112. Pieces of esophagus (1 g), diaphragm (1g) and heart were dissected under stereomicroscope to find Sarcocystis sp. cysts. Each heart sample of 1g was divided into 2 pieces and cysts were counted and measured in 0.5 g . Sarcocystis sp cysts were found in all heart (90), in 71 % (64/90) esophagus and in 28 % (25/90) diaphragm samples. All cysts were identified as S. cruzi on the basis of morphological criteria. Mean number of cysts/g of heart was 62 ±56.7 for CA, 70 ± 66.6 for CB and 100 ± 85,6 for CC. Mean length of cysts was 301 ± 95 µm for CA, 387 ± 107 µm for CB and 442 ± 107 µm for CC. The other half of the heart samples were fixed in 10% neutral buffered formalin. Paraffin embedded sections were stained with hematoxylin and eosin for histopathological studies. Microscopic lesions were not observed.  Neospora caninum cysts were not found. Immunohistochemical staining for detection of N. caninum was performed with the LSAB+ System HRP using a commercial kit (DakoCytomation, USA). N. caninum was not found. Sera were tested by the Indirect Immunofluorescence test (IFAT) with S. cruzi (Sc)  bradizoites recovered by bovine heart muscle digestion and NC-1 tachyzoites of N. caninum (Nc) as antigen, separately, from 1:25 dilution. Results of IFAT were: Titer <25 25 200 800 3200 classes infection Sc Nc Sc Nc Sc Nc Sc Nc Sc Nc CA 0 14 5 12 15 4 7 0 7 0 CB 0 5 3 5 10 8 14 1 3 0 CC 0 5 0 15 15 7 13 3 2 0 Association between titers of N.caninum and S.cruzi ( x2 ) was not detected.