Rumen fluke, Fischoederius elongatus (Trematoda: Gastrothylacidae): Preliminary investigation of suitable conditions for egg hatching.

Various temperatures may have different effects on the distribution of paramphistomes that cause amphistomosis in cattle, including Fischoederius elongatus. Therefore, this study aimed to investigate the effects of different temperature treatments on F. elongatus hatching, with specific identification using morphological, histological, and phylogenetic analysis. All specimens were collected from two buffalo (Bubalus bubalis) rumens in a slaughterhouse in Pathum Thani province, Thailand. F. elongatus adults were kept in phosphate buffered saline solution for egg collection. The egg specimens were incubated in tap water under four different temperature conditions: 4 °C, room temperature, 35 °C, and 55 °C. For 31 days, egg specimens of approximately 50 eggs per observation were randomly classified into three stages (undeveloped, developing (or pre-hatching), and hatched). To test the change of temperature, cold water was used for thermal shocking the egg specimens. The results indicated that rates of egg development and hatching were highest at 35 °C and significantly higher than in the other treatments (P < 0.001). In addition, statistical investigation of pre-thermal shock results also suggesting that 35 ºC may be a suitable condition for hatching F. elongatus eggs and could enhance the developing and hatching by longer periods of incubation for more than 26 days. Even changing the temperature could affect development and hatching but initial environment temperature remains an important factor. These data could be used for efficient epidemiological prediction of F. elongatus and applied in livestock management.