Canine hookworm infections are endemic worldwide, with zoonotic transmission representing a potentially significant public health concern. This study aimed to investigate hookworm infection and identify the prevalent species from stray and shelter dogs in Guangzhou city, southern China by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) based on internal transcribed spacer (ITS) sequences. From March 2011 to July 2012, fresh faecal samples from a total of 254 dogs were obtained from five locations, namely Conghua, Baiyun, Liwan, Haizhu and Panyu, in Guangzhou. These samples were screened for the presence of hookworm eggs using light microscopy, with an overall prevalence of 29.53% being recorded. The highest prevalence of 45.28% was found in suburban dogs from Conghua compared with lower values recorded in urban dogs in Haizhu (21.43%), Baiyun (18.97%), Panyu (18.18%) and Liwan (15%). The prevalence in stray dogs was significantly higher than that in shelter dogs. PCR-RFLP analysis showed that 57.33% were detected as single hookworm infections with Ancyclostoma caninum, and 22.67% as A. ceylanicum, while 20% were mixed infections. This suggests that high prevalences of both hookworm species in stray and shelter dogs in China pose a potential risk of transmission from pet dogs to humans.
Ancylostoma caninum is a blood-feeding parasitic intestinal nematode which infects dogs, cats, and other mammals throughout the world. A highly sensitive and species-specific PCR-RFLP technique was utilised to detect the prevalence of A. caninum in cats in Guangzhou, southern China. Of the 102 fecal samples examined, the prevalence of A. caninum in cats was 95.1% and 83.3% using PCR-RFLP and microscopy, respectively. Among them, the prevalence of single hookworm infection with A. caninum was 54.90%, while mixed infections with both A. caninum and A. ceylanicum were 40.20%. Comparative analysis of three complete ITS sequences obtained from cat-derived A. caninum showed the same length (738 bp) as that of dog-derived A. caninum. However, the sequence variation range was 98.6%–100%, where only one cat isolate (M63) showed 100% sequence similarity in comparison with two dog-derived A. caninum isolates (AM850106, EU159416) in the same studied area. The phylogenetic tree revealed A. caninum derived from both cats and dogs in single cluster. Results suggest that cats could be the main host of A. caninum in China, which may cause cross-infection between dogs and cats in the same area.
This study aimed to identify the assemblages (or subassemblages) of Giardia duodenalis by using normal or nested PCR based on 4 genetic loci: glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi), β-giardin (bg), and small subunit ribosomal DNA (18S rRNA) genes. For this work, a total of 216 dogs' fecal samples were collected in Guangdong, China. The phylogenetic trees were constructed with MEGA5.2 by using the neighbor-joining method. Results showed that 9.7% (21/216) samples were found to be positive; moreover, 10 samples were single infection (7 isolates assemblage A, 2 isolates assemblage C, and 1 isolate assemblage D) and 11 samples were mixed infections where assemblage A was predominant, which was potentially zoonotic. These findings showed that most of the dogs in Guangdong were infected or mixed-infected with assemblage A, and multi-locus sequence typing could be the best selection for the genotype analysis of dog-derived Giardia isolates.
To assess the effects of abiotic factors on Argulus japonicus occurrence in freshwater ecosystem, we sampled fish, free-swimming parasites, and submerged objects from rivers, fish farms, and ponds (reservoirs and lakes) at 27 locations in Guangdong province, China, from July, 2010, to March, 2013. Friedman's test and Spearman's correlation coefficient (r) were used to investigate relationship between A. japonicus occurrence and abiotic factors in three aquatic systems. Correlation of monthly density, mean density, prevalence, abundance, and intensity of A. japonicus with water temperature, biochemical oxygen demand of 5 days, chemical oxygen demand, and ammonia were very significant, but negative relation with pH, dissolved oxygen, and total phosphorus components. Nevertheless, total nitrogen components showed an insignificant impact on A. japonicus incidence. In addition, water temperature and stability were two key factors controlling A. japonicus infestation. Our study revealed the capability of A. japonicus to inhabit and prevail in heavily polluted freshwater. Results demonstrate that A. japonicus has good adaptability to the environmental factors' stress but cannot be used as a biological indicator of environmental pollution.
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