Brazilian Horses from Bahia State Are Highly Infected with Sarcocystis bertrami

Sporocysts of Sarcocystis bertrami (syn. Sarcocystis fayeri) shed by dogs: Molecular analysis, morphometry and pattern of excretion

Sarcocystis bertrami (synonym: Sarcocystis fayeri) is a coccidian parasite that infects horses and donkeys in several countries. Dogs are known as definitive hosts of the parasite, however, the patent period is not well defined, and S. bertrami shed by dogs has never been confirmed by molecular methods. Here we investigated the shedding of S. bertrami by experimentally infected dogs and examined the excreted parasites by morphological and molecular tools. Three dogs of small breeds (one Yorkshire terrier and two miniature Pinschers) were acquired with ages of 30 and 60 days and were exclusively fed commercial dog food. Two dogs consumed equine muscle tissues containing cysts of S. bertrami. The third dog served as negative control and was simultaneously fed commercial dog food. The two animals that received equine tissues shed sporocysts and/or oocysts in their feces after prepatent periods of 13 and 23 days. The patent periods were 47 and 14 days. Sporocysts showed average dimensions of 14.19 µm (± 0.53) x 10.06 µm (± 0.44). The control dog did not shed sporocysts or oocysts of the parasite. Interestingly, patent periods had never been reported, and for one dog, the patent period (47 days) was longer than that reported for other Sarcocystidae parasites. PCRs to the gene 18S and to the internal transcribed spacer 1 (ITS1) of the rDNA were successfully performed with DNA extracted from sporocysts. ITS1 sequences were also obtained from the equine tissue cysts used to infect the dogs. Nucleotide sequences of cloned fragments of 18S from sporocysts, and ITS1 from both stages (tissue cysts and sporocysts) matched with S. bertrami (18S: 97.50-99.88 %; ITS1: 88.76-95.21 %), although high molecular diversity was observed with data from these loci. PCR to cox1 using sporocysts' DNA failed to amplify any product. The possibility of the existence of an additional and undescribed Sarcocystis species in the excreted sporocysts, besides S. bertrami, cannot be excluded from this experiment. To our knowledge, this is the first molecular confirmation of S. bertrami in canine feces. Sporocyst dimensions and prepatent periods observed in this study were similar to those previously described for S. bertrami and S. fayeri. In conclusion, the molecular, morphological and biological data generated here fit in previous descriptions for both S. bertrami and S. fayeri.

Diversity of Sarcocystis parasites in southeastern Baltic Sea catchment ecosystems

Currently, research on apicomplexan Sarcocystis parasites is mainly carried out by analyzing animal carcasses. However, environmental studies would not only allow faster detection of possible sources of infection but also avoid the use of animals for investigations. Therefore, in the current study, we aimed to identify tested Sarcocystis species in sediment collected from water bodies located in the southeastern Baltic countries. A total of 99 sediment samples were collected during the summer from different types of water bodies in Estonia, Latvia, Lithuania, and Poland. Species-specific nested PCR targeting cox1 gene was used for the detection of selected Sarcocystis species (S. cruzi, S. bovifelis, S. hirsuta, S. arieticanis, S. tenella, S. capracanis, S. miescheriana, and S. bertrami) infecting livestock. The results showed a statistically lower (p < 0.05) occurrence of Sarcocystis parasites in Estonia (50%) compared to three countries, where the detection rate of Sarcocystis spp. DNA was remarkably higher, ranging from 88 to 100%. Among Sarcocystis species tested, S. cruzi (83.8%) and S. arieticanis (55.6%) using cattle and sheep as their intermediate hosts were most commonly identified. The detection rates of some of the analyzed Sarcocystis species were significantly different in southeastern Baltic countries. It is discussed that the detection rates of certain Sarcocystis species depend not only on the number of animals per 1 km2 but also on various ecological factors and farming practices that differ in the amount of contact domestic animals have with predators and the potential for animals to become infected through natural water or food sources.

Sarcocystis in horses from Rio Grande do Sul, Brazil: Molecular identification of Sarcocystis bertrami and Sarcocystis neurona in muscle tissues

Horses are intermediate hosts of Sarcocystis spp. capable of forming cysts in their musculature. This study aimed to detect sarcocysts and investigate the presence of nucleic acids from Sarcocystis spp. in samples of striated muscles from horses in the State of Rio Grande do Sul, Brazil, necropsied at the Veterinary Pathology Laboratory of the Federal University of Santa Maria. A total of 108 samples were collected from 24 horses and examined through direct examination. Microscopic tissue cysts were observed in three samples: tongue (2) and esophagus (1) from two animals. Extractions were performed on the found cysts and tissues, even though sarcocystosis detection was not present. DNA samples were subjected to Nested-PCR using Tg18s primers, and the amplified products were subjected to Restriction Fragment Length Polymorphism (RFLP) using DdeI and HpaII enzymes. DNA belonging to Sarcocystis spp. was amplified in tissues from 91.7% (22/24) of the equines, and 67.6% (73/108) of the samples tested positive in the Nested-PCR reaction. The tissues with the highest detection frequency were: diaphragm 92.3% (12/13), gluteal muscle 77.2% (17/22), and esophagus 66.7% (4/6). In RFLP, Sarcocystis spp. was detected in 21 tissues from 11/22 equines, and cysts, identified through nucleotide sequencing, were determined to be S. bertrami. S. neurona was identified in 11 samples from 7/22 animals, with co-infection detected in 5/22 cases. The high detection rate indicates a concerning circulation of the protozoan, particularly the zoonotic S. bertrami found in all tissues, which are commonly exported for human consumption.