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Cryptosporidium spp., Giardia duodenalis, and Blastocystis sp. are common intestinal protozoans that infect humans and animals worldwide. A survey that assessed the prevalence, molecular characteristics, and zoonotic potential of these pathogens was conducted on a variety of dogs in Guangzhou, southern China. A total of 651 canine stool samples from household (n = 199), shelter (n = 149), breeding (n = 237), and pet market dogs (n = 66) were collected from eight districts in Guangzhou. Cryptosporidium spp., Giardia duodenalis, and Blastocystis sp. were detected by PCR amplification of the SSU rRNA gene. Giardia duodenalis-positive specimens were further assigned into assemblages using the glutamate dehydrogenase gene. Cryptosporidium spp., G. duodenalis, and Blastocystis sp. were found in 21 (3.2%), 20 (3.1%), and 35 (5.4%) samples, respectively. The overall prevalence of shelter dogs (40.28%, 60/149) was significantly higher than that of household (3.0%, 6/199), breeding (2.1%, 5/237), and pet market dogs (7.5%, 5/66) (χ 2  = 154.72, df = 3, P < 0.001). Deworming in the past 12 months had a strong protective effect on the risk of contracting parasite infections (P < 0.001). No significant differences were detected between age or sex groups (P > 0.05). Dog-specific C. canis (n = 19) and zoonotic C. parvum (n = 2) were the only two Cryptosporidium species. Sequence analysis revealed the presence of three G. duodenalis assemblages: dog-specific assemblages D (n = 14) and C (n = 5), and cat-specific F (n = 1). Zoonotic Blastocystis ST3 (n = 28) was the dominant subtype, followed by ST1 (n = 6) and ST10 (n = 1). To our knowledge, this is the first large-scale investigation on the occurrence and molecular characteristics of Blastocystis sp. in dogs in China. Our results indicated that the dogs seemed to play a negligible role as reservoirs for Cryptosporidium spp. and G. duodenalis transmission to humans, but they are potential novel suitable hosts of Blastocystis sp. A strict sentinel surveillance system of dogs should be established to minimise the zoonotic risk of spreading blastocystosis among humans and dogs.

Hookworm infection is globally prevalent among dogs and cats representing a major public health risk. Although previous studies have surveyed canine and feline hookworms in Guangzhou city, the status of these infection needs to be further explored in other regions of South China. To investigate the prevalence and zoonotic risk of canine and feline hookworms in eight cities (Guangzhou, Foshan, Shenzhen, Huizhou, Zhongshan, Shaoguan, Shantou and Chaozhou) of Guangdong province, China, we developed specific PCR methods based on ITS sequence for identifying three common hookworm species. The results showed that the prevalence of hookworms from stray dogs and cats was 20.23% (142/702) and 15.26% (47/308), respectively. The established PCR methods could identify Ancylostoma ceylanicum, A. caninum and A. tubaeforme. The mixed infections of A. caninum and A. ceylanicum were detected in stray dogs of Guangzhou and Shaoguan, with the rate of 8.3% and 21.2%, respectively. Among the stray dogs in Foshan, the infection rate of A. ceylanicum was higher than that of A. caninum. The stray cats in four of five investigated cities were infected with A. ceylanicum. The different region, age and rearing environments had an impact on the hookworm infection rates of stray dogs and cats. In conclusion, the reported higher infection rate of A. ceylanicum than other hookworm species in stray dogs and cats poses a potential risk to public health., (Copyright © 2019. Published by Elsevier B.V.)

Background: Enterocytozoon bieneusi, a common opportunistic fungal pathogen, has a wide range of hosts. Limited epidemiological data on E. bieneusi intestinal infections in companion animals (dogs and cats) in China exists. In this study, fecal samples (651 from dogs and 389 from cats) in Guangzhou city, Guangdong Province, China, were collected, and the ribosomal internal transcribed (ITS) spacer region from the DNA extracted from them was Polymerase Chain Reaction (PCR)-amplified and sequenced. Results: Based on the sequencing data, E. bieneusi was identified in the fecal samples collected from 149 (22.9%) and 79 (20.3%) dogs and cats. Of the factors investigated, poor living conditions appeared to be the major risk factor for contracting the pathogen. Eleven E. bieneusi genotypes, six known (PtEb IX, GD1, D, CD9, EbpC, I) and five novel (designated here as GD2– GD6), were found in dogs. Eight genotypes, six known (PtEb IX, GD1, D, CD9, EbpC, Type IV) and two novel (GD2 and GC1), were identified in cats. Genotype PtEb IX was most common in both dogs and cats, followed by genotype GD1. Conclusions: Although PtEb IX was the most common E. bieneusi genotype in dogs, this is the first report of this genotype dominating in cats. The same genotype distribution of the pathogen between the two different companion animals species in the same geographic area indicates that inter-species transmission is probable. The widespread existence of zoonotic E. bieneusi genotypes (D, EbpC, Type IV) in companion animals indicates that they are potential sources of environmental contamination and infections in humans. [ABSTRACT FROM AUTHOR]

To develop a Tm-shift method for detection of dog-derived Ancylostoma ceylanicum and A. caninum, three sets of primers were designed based on three SNPs (ITS71, ITS197, and ITS296) of their internal transcribed spacer 1 (ITS1) sequences. The detection effect of the Tm-shift was assessed through the stability, sensitivity, accuracy test, and clinical detection. The results showed that these three sets of primers could distinguish accurately between A. ceylanicum and A. caninum. The coefficient of variation in their Tm values on the three SNPs was 0.09% and 0.15% (ITS71), 0.18% and 0.14% (ITS197), and 0.13% and 0.07% (ITS296), respectively. The lowest detectable concentration of standard plasmids for A. ceylanicum and A. caninum was 5.33 × 10−6 ng/μL and 5.03 × 10−6 ng/μL. The Tm-shift results of ten DNA samples from the dog-derived hookworms were consistent with their known species. In the clinical detection of 50 fecal samples from stray dogs, the positive rate of hookworm detected by Tm-shift (42%) was significantly higher than that by microscopic examination (34%), and the former can identify the Ancylostoma species. It is concluded that the Tm-shift method is rapid, specific, sensitive, and suitable for the clinical detection and zoonotic risk assessment of the dog-derived hookworm. [ABSTRACT FROM AUTHOR]