ABSTRACT
The occurrence of Sarcocystis species was investigated in synanthropic (Muridae) and wild (Cricetidae) rodents from Argentina. Nine species were captured (n = 356). Sarcocysts were detected in muscles of 8.7% (31/356) and 3.7% (4/106) of the rodents by histopathology and direct microscopic observation, respectively. PCR-sequencing targeting the 18S rRNA, cox1, and ITS1 regions was performed on samples with positive histopathology. Four different 18S rRNA sequences or sequence groups with high intra-group identities (99.6-100%) were detected in Mus musculus, Oxymycterus rufus, Akodon azarae, and Necromys lasiurus. Eight sequences showed 99.5-99.7% identity with S. dispersa. Thirteen sequences showed low identity (95.3-96.4%) with other Sarcocystis spp. The obtained coxI sequences (n = 9) were almost identical to each other and showed a high similarity with S. strixi (99.2-99.5%) and S. lutrae (99.1%), despite the 18S rRNA sequences from the same samples suggested the occurrence of at least two species. This suggests that coxI may not show high variability in Sarcocystis spp. that use rodents as intermediate hosts. Six ITS1 sequences were obtained, showing high identity but low coverage with several Sarcocystis spp. Multilocus sequence typing and BLAST analysis did not lead to an accurate species identification. Possible reasons are the detection of new species or the limited molecular information available from previously described Sarcocystis spp. Phylogeny suggests that the detected Sarcocystis spp. may use raptor birds or snakes as definitive hosts. This study represents the first molecular identification of Sarcocystis spp. in naturally infected rodents of the Cricetidae and Muridae families in South America.
Subject(s)
Sarcocystis , Sarcocystosis , Humans , Animals , Sarcocystosis/veterinary , Sarcocystosis/epidemiology , RNA, Ribosomal, 18S/genetics , Muridae/genetics , Arvicolinae , Argentina , PhylogenyABSTRACT
In order to optimize the survival rate of animals, the purpose of this study was to evaluate an injectable anesthesia protocol for the development of a murine model of hepatic cystic echinococcosis in female CF-1 mice. Three protocols of injectable anesthesia were evaluated during the infection of mice with Echinococcus granulosus sensu lato protoscoleces via the portal vein. The use or not of pre-anesthesia [atropine (0.4 mg/kg) and tramadol (2 mg/kg)] and the incorporation or not of yohimbine (0.5 mg/kg) (a reverser of xylazine) in mice anesthetized with ketamine/xylazine 80/8 mg/kg were evaluated. Most mice treated only with ketamine/xylazine 80/8 mg/kg did not achieve a deep surgical anesthetic plane. All mice treated with pre-anesthetic drugs achieved a deep surgical anesthetic plane after the administration of the anesthetic cocktail. Pre-anesthetic drugs application significantly reduced time induction of animals compared with those that received only anesthetic cocktail. Recovery time was significantly faster in the group that received yohimbine. Mice underwent laparotomy that did not receive yohimbine after surgery had a survival rate of 67%, whereas in the group treated with yohimbine the survival was 100 %. We recommend the protocol that applied pre-anesthetic drugs + ketamine/xylazine 80/8 mg/kg + yohimbine, as safe and reliable for the portal vein infection of mice with protoscoleces of E. granulosus sensu lato.
ABSTRACT
Several Sarcocystis spp. have carnivores as definitive host and sarcocysts are common in muscles of herbivores (intermediate host). However, sarcocysts have been found in muscles of wild and domestic carnivores suggesting they are intermediate host for some Sarcocystis spp. Here, we report mature sarcocysts in the muscles of Pampas fox (Lycalopex gymnocercus). A total of 36 free-living foxes were analyzed. Different skeletal muscles were assessed by microscopic and molecular methods. Cysts and/or DNA of Sarcocystis sp. were detected in 61.1% (22/36) foxes. Histopathology revealed the presence of sarcocysts in 52.8% (19/36) foxes. The tongue and masseter were the muscles more frequently infected. Of all the samples processed by homogenization of pooled muscles of each animal, 45.4% (10/22) evidenced muscle cysts and 68.2% (15/22) resulted positives by PCR. Individual cysts obtained from the ten positive samples in direct microscopic examination were all positive by PCR. Five amplicons from individual cysts from different samples were selected for sequencing together with four PCR products obtained from the pooled muscles. All nine sequences shared a high identity among them (99.8-100%) and showed the highest identity by BLAST (99%) with a S. svanai sequence (KM362428) from a North American dog. By transmission electron microscopy, the sarcocyst wall was thin (<1µm), had minute undulations, with tiny evaginations and without evident villar protrusions. The cyst wall type is referred as "type 1". Sarcocystis svanai infects L. gymnocercus with a high prevalence and the presence of mature sarcocysts suggests the role of the Pampas fox as natural intermediate host. The definitive host of S. svanai remains unknown.
