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The purpose of the research is to determine taxa of the genus Cryptosporidium species in pigs using molecular genetic methods in the north-west of the Russian Federation.Materials and methods. Fecal samples were taken from pigs of different age groups on farms of different types of incorporation that differ in climatic and geographical zones and animal keeping technologies in the Vologda Region. Microscopic research methods identified “positive” samples in which Cryptosporidium species were present; they were sorted out and deep-frozen. Then the samples were examined using the equipment of the resource center «Genomic Technologies, Proteomics and Cell Biology» of ARRIAM. The Cryptosporidium species in the fecal samples from farm animals were identified using high-throughput sequencing of 18S rRNA gene amplicon libraries obtained by a nested polymerase chain reaction (PCR) assay.Results and discussion. A primer system was designed for the nested PCR to amplify a potentially species-specific 393 bp fragment of the 18S rRNA gene. The sequence of the ILL_R2_ Zheng primer was modified with included degenerated positions to make the primer more versatile. As a result of sequencing of the libraries of 18S rRNA gene fragments obtained with the selected primers and subsequent taxonomic analysis of the nucleotide sequences, it was shown that all the studied samples included representatives of only one species, Cryptosporidium scrofarum.

The purpose of the research is to determine infection rate and oocyst isolation degree followed by identification of taxa of Cryptosporidium species in piglets of different age groups using the latest molecular genetic methods, on private farms in the Vologda Region of the North-Western Federal District of the Russian Federation.Materials and methods. These studies were performed in the Russian Federation for the first time. The research was performed on private pig farms located in the Vologda Region of the North-Western Federal District of the Russian Federation from January to September 2022. Feces were taken from piglets of different age groups, namely, sucklings under the age of 1 month, weaners (1–3 months), feeder pigs (4 months and older), as well as from milking sows. Age groups were formed taking into consideration technological parameters of keeping animals on farms. Using microscopic research methods, “positive” samples were detected in which Cryptosporidium oocysts were found, and the number of oocysts was determined. Subsequently, the samples were studied using the equipment of the resource center «Genomic Technologies, Proteomics and Cell Biology» of ARRIAM. Cryptosporidium species were identified in samples of animal feces using high-throughput sequencing of 18S rRNA gene fragment amplicon libraries as obtained by nested PCR.Results and discussion. Cryptosporidium species were identified in each studied age group both in the animal’s presenting indigestion and the animals without any clinical sign of the disease. The average cryptosporidium infection rate was 32.4% in the animals on private farms. The most infected with cryptosporidium oocysts were feeder pigs aged 4–6 months (72%). As a result of sequencing of 18S rRNA gene fragment amplicon libraries obtained using selected primers and subsequent taxonomic analysis of the resulting nucleotide sequences, it was shown that only representatives of the Cryptosporidium scrofarum species were present in all the studied samples.

Cryptosporidiosis is a widespread parasitic disease of many species of domestic and wild animals, as well as humans, which is a significant problem in the field of medicine and veterinary medicine. Farm animals, in particular piglets, are most often susceptible to this disease, but the species composition of representatives of the genus Cryptosporidium in this species of animals in the Russian Federation has remained unknown to date. For the first time in the Russian Federation, in the conditions of the north-west, on the example of the Vologda region in pig farms with industrial technology for keeping piglets using the latest molecular genetic techniques, namely, using high-throughput sequencing of amplicon libraries of fragments of the 18S rRNA gene obtained as a result of nested PCR, we have established parasitism of C. scrofarum in all age groups of the animals examined. The total invasion of livestock in pig farms was 34% (51/150). Pine piglets were invaded by Cryptosporidium in 40% of cases (12/30), the intensity of Cryptosporidium infection was predominantly strong (+ + +), occurred in 20% (6/30) of cases. The mean (+ +) and weak (+) degree of animal invasion also occurred in 3% (10/30) of cases each. In the age group of weaning piglets at the age of 1-3 months, Cryptosporidium infection was 33.3% (10/30), a strong (+ + +) degree of oocyst production dominated, it was 26.7% (8/30) versus 10% (3/30) of the average (+ +) and 3.3% (1/30) weak (+). The most invasive oocysts are Cryptosporidium of fattening piglets at the age of 4-6 months, the extensinvasion of this group was 60% (18/30). The degree of oocyst release was predominantly moderate (+ +) – 26.7% (8/30) and strong – 23.3% (7/30). In 13.3% (4/30) of cases, there was a weak (+) degree of Cryptosporidium infection . Animals older than 6 months were infected with Cryptosporidium in 20% (6/30) of cases. They also recorded an average (+ +) – 13.3% (4/30) and a strong (+ + +) – 6.7% (2/30) degree of invasion, weak (+) invasion in this age group was not detected. Sows have also been invaded by Cryptosporidium. Their infection rate was 16.7% (5/30), and the degree of cryptosporidiosis was weak (+).

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