Molecular identification of Colpodella sp. of South China tiger Panthera tigris amoyensis (Hilzheimer) in the Meihua Mountains, Fujian, China.

A three-year-old male South China tiger died in the tiger enclosure of the China Tiger Park in the Meihua Mountains on December 2018 after being bitten by a tick. This tiger presented clinical symptoms like whole-body severe jaundice, hepatosplenomegaly, kidney, and lymph node hemorrhages. The Colpodella sp.-specific 18S rRNA gene was detected using nested PCR. Interestingly, the DNA isolated from the blood of the tiger was found to be 100% similar to that of the tick by NCBI BLAST analysis. However, the DNA fragments isolated from the tiger's blood were 90.1% similar to the Colpodella sp. strain human erythrocyte parasite (HEP, MH208621) and 90.4% similar to the Colpodella sp. strain Heilongjiang (HLJ, KT364261). To investigate the species of ticks and ticks-carried Colpodella parasites in this region, the species of ticks obtained from the grasses outside the tiger enclosure and the species of Colpodella carried by ticks were identified. The DNA from ticks as well as that from the tick-borne Colpodella sp. were amplified from each tick using PCR followed by amplicon sequencing. In total 402 adult ticks samples were collected, among which 22 were positive for Colpodella sp. (5.5%), and the species were further determined by morphology, DNA sequencing and phylogenetic analyses. Interestingly, one Colpodella sp. was found to have 94.2% sequence similarities to the Colpodella sp. strain HEP (MH208621). This strain was previously reported to infect a woman in Yunnan, China. In addition, three Colpodella sp. showed 87-91% sequence similarities to the Colpodella sp. strain HLJ (KT364261), which was previously reported to infect human in Heilongjiang, China. This study disclosed the possibility of zoonotic transmission of Colpodella sp. by ticks in China. Finally, it provides a basis for urgently determining and monitoring the repertoire of ticks-borne piroplasmid pathogens, with the ultimate aim of strategic control.

Genetic and epidemic characteristics of porcine parvovirus 7 in the Fujian and Guangdong regions of southern China.

Porcine parvovirus (PPV) is the primary cause of reproductive disorders in pigs. The porcine parvovirus 7 (PPV7) subtype was first identified in the United States in 2016. In this study, PPV7 was detected in different porcine samples, including serum, feces, saliva, and milk, from 69 pig farms in the Fujian and Guangdong regions of South China, and its coinfection with porcine circovirus 2 (PCV2), porcine circovirus 3 (PCV3), and porcine reproductive and respiratory syndrome virus (PRRSV) was determined. Whole-genome sequencing, phylogenetic analysis, and recombination analysis were performed on seven isolates, with each selected isolate originating from a different farm. There was a high rate of PPV7 positivity in blood, stool, and saliva but PPV7 DNA was absent from breast milk. The findings also showed that PPV7-positive samples had a high rate of coinfection with PCV2, PCV3, and PRRSV. Real-time PCR was used to determine the viral copy numbers of PCV2, PCV3, PRRSV, and PPV7 in serum samples and to assess whether PPV7 affected PCV2, PCV3, and PRRSV viral loads. Phylogenetic analysis showed that PPV7e and PPV7f were the most prevalent and widespread subtypes in the Fujian and Guangdong regions, respectively. While the PPV7a, PPV7b, PPV7c, and PPV7f subtypes were most prevalent in Fujian Province, PPV7a-e subtypes were prevalent in Guangdong, indicating that PPV7 has rich genetic diversity in these regions. A putative recombinant strain, 21FJ09, was identified using SimPlot and the Recombination Detection Program 4 software.