Modified use of methylene blue in the tissue compression technique to detect sarcocysts in meat-producing animals

- Our study demonstrated methylene blue stained tissue compression technique was able to detect three-fold more sarcocysts in comparison to the unstained tissue compression preparation.
- Methylene blue stained tissue compression technique is as sensitive as the standard molecular technique in diagnosing sarcocystosis.
- Methylene blue stained tissue compression technique is rapid and inexpensive compared to the molecular technique.

Sarcocystosis in meat-producing animals is a major cause of reduced productivity in many countries, especially those that rely on agriculture. Although several diagnostic methods are available to detect sarcocystosis, many are too time-consuming for routine use in abattoirs and meat inspection centers, where large numbers of samples need to be tested. This study aimed to compare the sensitivity of the methylene blue tissue preparation, unstained tissue preparation and nested PCR in the detection of sarcocysts in tissue samples. Approximately three-fold more sarcocysts were detected in methylene blue-stained tissue compared to unstained controls (McNemar's test: P < 0.01). Test sensitivity was comparable to that of the gold standard for sarcocyst detection, nested polymerase chain reaction. These results suggest that methylene blue can be used in tissue compression as a rapid, safe, and inexpensive technique for the detection of ruminant sarcocystosis in abattoirs.