Zur Klinik, Enzymaktivität und Antikörperbildung bei experimentell mit Sarkosporidien infizierten Pferden1

Brazilian Horses from Bahia State Are Highly Infected with Sarcocystis bertrami

The protozoan Sarcocystis bertrami (syn. Sarcocystis fayeri) infects horses and has dogs as definitive hosts. Herein we aimed to detect S. bertrami in Brazilian horses destined for human consumption and to determine the frequency of infection in the examined animals. Muscle fragments from 51 horses were collected in a slaughterhouse in Bahia State during three different seasons of the year. Samples from six tissues from each animal were prepared for macroscopic and microscopic evaluation, using tissue grinding, squash and histology. Sarcocystis sp. was observed in 100% of the examined horses. Selected samples were processed for transmission electron microscopy (TEM). Species identification was confirmed using a PCR targeted to the mitochondrial cytochrome c oxidase subunit 1 gene (cox1). Histological examination revealed sarcocysts with variable sizes and shapes, and dispersed within the muscle fibers. When observed by TEM, the sarcocyst wall was wavy and covered by an electrodense layer. The villar protrusions were digitiform and bent. To our knowledge, this study is the first morphological and molecular confirmation of S. bertrami in horses in Brazil and South America.

The effects of Sarcocystis miescheriana infections on blood enzymes and weight gain of stress-sensitive and stress-insensitive pigs

The effects of mild Sarcocystis miescheriana infection on blood enzymes and body weight were compared in stress-sensitive (halothane positive) and in stress-insensitive (halothane negative) pigs. Ten halothane-positive pigs (Group A) and ten halothane-negative pigs (Group C) with a mean body weight of 36 kg were each inoculated orally with 50,000 sporocysts of S. miescheriana. Twelve halothane-positive pigs (Group B) and ten halothane-negative pigs (Group D) served as non-infected controls. Five days before infection (a.i.) and 58 days post infection (p.i.) all pigs were myostress challenged (creatine kinase test). During the whole period of the experiment (3 weeks a.i. to 13 weeks p.i.) body weights were determined and blood samples taken at weekly intervals. Creatine kinase (CK), aspartate aminotransferase (ASAT) and Sarcocystis antibody titres were determined. The infection induced slightly elevated temperatures (max. 42.8 degrees C) and transient reduced food intake during the 2nd and 3rd week p.i. The CK values of the infected pigs in Groups A and C increased from Day 28 p.i. onwards, and were significantly higher than those of the pigs of the non-infected controls (Days 35-77 p.i.). The ASAT values of the infected groups (A and C) increased from Day 21 p.i. onwards, and were significantly higher than those of the non-infected controls from Days 28-77 p.i. The myostress injection at 5 days a.i. (1st CK test) resulted in significantly higher CK and ASAT values in stress-sensitive pigs.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of enzyme-linked immunosorbent assay and indirect fluorescent antibody test for the detection of IgG antibodies to Sarcocystis muris

Sarcocystis muris cystozoites were separated from host tissue after mechanical mincing and homogenization by discontinuous density gradient centrifugation using Percoll. The isolated antigen, consisting of more than 95% cystozoites, was used in an enzyme-linked immunosorbent assay (ELISA) and an indirect fluorescent antibody test (IFAT). In the ELISA, the antigen was used at a very low protein concentration of 0.44 micrograms/ml. Good reproducibility of test results was achieved with different conjugates and different reference sera when the measured optical densities were converted into an index related to a standard. From the examination of 500 sera from non-infected mice, and index of 0.300 at a serum dilution of 1:10 was determined as the threshold for a positive reaction in the ELISA. Specific antibodies were first detected between 18 and 49 days after experimental infection (dpi) with S. muris. The ELISA as well as the IFAT was highly sensitive from about 50 dpi onwards and detected antibodies up to the end of the examination period (182 dpi). However, the IFAT with unfixed antigen appeared more sensitive than the ELISA for the period of infection before 50 dpi and detected specific antibodies between 11 and 25 dpi starting with fluorescence at the apical pole of the cystozoite and resulting in bright fluorescence of the whole cystozoite from 32 or 35 dpi onwards. Both serotests showed only slight crossreactions with high titred Toxoplasma gondii sera at a serum dilution of 1:10. The activity of the antigen lasted for at least 13 months in the ELISA and for at least eight months in the IFAT.