Morphologic characterization of Sarcocystis spp. histologically detected from the diaphragm and tongue of Rattus norvegicus and Rattus tanezumi
Cristina G. Cabanacan-Salibay1,2,*, Florencia G. Claveria3, Hazel Anne Luyon-Tabo1,2, Steven Paulo C. Salibay4, Augusto C. Sumalde5, Mario S. Torres1,2, Julieta Zabal-Dungca6
1Biological Sciences Department, College of Science and Computer Studies, De La Salle University, Dasmariñas, Cavite, Philippines
2Graduate Studies Department, College of Science and Computer Studies, De La Salle University, Dasmariñas, Cavite, Philippines
3Biology Department, College of Science, De La Salle University, Taft Avenue, Manila, Philippines
4Department of Biological Sciences, College of Arts and Sciences, Cavite State University, Main Campus, Indang Cavite, Philippines
5Institute of Weed Science, Entomology and Plant Pathology, College of Agriculture, University of The Philippines, Los Baños, College, Laguna, Philippines
6School of Science and Technology, Centro Escolar University, Mendiola, Manila, Philippines
Abstract
This study focused on the detection of Sarcocystis spp. in two species of rats, Rattus norvegicus and R. tanezumi collected from agricultural area in Dasmarinas, Cavite. This aimed to corroborate the presence of Sarcocystis spp. in different species of rats found in the agricultural area. Further the establishment of different Sarcocystis spp in Rattus spp. based on the parasite’s morphologic characterization is also emphasized. Sixty-nine rats (36 R. norvegicus and 33 R. tanezumi) were collected through trapping. Individual rodent autopsy for host identification was performed by determining the morphological differences and external measurements prior to dissection. Tissue samples were examined for the presence of white rice-grain sized nodules. Morphological characteristics of the cysts, particularly the size, shape, and presence of protrusions were noted. Statistical analysis using ANOVA for the significant difference on the number of infected rats per species and across muscle type was done at p≤0.05. Infection in R. tanezumi was higher (48.48%) as compared to R. norvegicus (41.67%), the difference however was not significant. Sarcocysts burden was higher in the diaphragm in both rat species. Generally, higher parasite load was observed in R. norvegicus.In both rat species, tissue cysts ranged from spindle-shaped/fusiform to globular and oval-shaped. The sarcocysts in the diaphragm were more varied. Consistently observed in the tongue were globular–shaped sarcocysts while either fusiform- and globular-shaped sarcocysts in the diaphragm. These differences suggest infection with more than one species of Sarcocystis. Hence,the presence of Sarcocystis spp. confirmed the infectivity of the parasite to Rattus spp. Moreover, the different morphologic characteristics observed on Sarcocystis prove the possibility of different species of the parasite harboring the Rattus spp.
