Molecular detection, risk factors, and phylogenetic analysis of tick-borne pathogens in dogs from northern Vietnam

@#In tropical regions, numerous tick-borne pathogens (TBPs) play a crucial role as causative agents of infectious diseases in humans and animals. Recently, the population of companion and pet dogs has significantly increased in Vietnam; however, information on the occurrence of TBPs is still limited. The objectives of this investigation were to determine the occurrence rate, risk factors, and phylogenetic characteristics of TBPs in dogs from northern Vietnam. Of 341 blood samples tested by PCR, the total infection of TBPs was 73.9% (252/341). Babesia vogeli (18SrRNA gene – 30.5%) was detected most frequently in studied dogs followed by Rickettsia spp. (OmpA gene – 27%), Anaplasma platys (groEL gene – 22%), Bartonella spp. (16SrRNA – 18.8%), Mycoplasma haemocanis (16SrRNA – 9.4%) and Hepatozoon canis (18SrRNA gene – 1.2%), respectively. All samples were negative for Ehrlichia canis and Anaplasma phagocytophylum. Co-infection was detected in 31.4% of the samples (107/341) of which, A. platys/Bartonella spp. (34/94,10%), Rickettsia spp./B. vogeli (19/94, 5.6%), and M. haemocanis/B. vogeli (19/94, 5.6%) were recorded as the three most frequent two species of co-infection types. Statistical analysis revealed a significant correlation between TBP infection and several host variables regarding age, breed, and living area in the current study. The recent findings reported herein, for the first time in Vietnam, are essential for local veterinarians when considering the appropriate approaches for diagnosing these diseases. Furthermore, this data can be used to establish control measures for future surveillance and prevention strategies against canine TBPs in Vietnam.

Construction of a recombinant vaccinia virus expressing Babesia gibsoni thrombospondin-related anonymous protein and evaluation of its immunogenicity in mice

@#Previously, we have identified a gene encoding thrombospondin-related anonymous protein of Babesia gibsoni (BgTRAP), and have shown that the antisera raised against recombinant BgTRAP expressed in Escherichia coli inhibited the growth of parasites. In the present study, a recombinant vaccinia virus expressing the BgTRAP (VV/BgTRAP) was constructed. A specific band with a molecular mass of 80 kDa, which is similar to that of native BgTRAP on the merozoites of B. gibsoni, was detected in the supernatant of VV/ BgTRAP-infected RK13 cells. Mice inoculated with VV/BgTRAP produced a specific antiBgTRAP response. The antiserum against VV/BgTRAP showed reactivity against the native BgTRAP on parasites. These results indicated that the recombinant vaccinia virus expressing BgTRAP might be a vaccine candidate against canine B. gibsoni infection.

Seroprevalence of Toxoplasma gondii infection in sheep from northern China

@#Toxoplasma gondii is an important zoonotic parasite causing significant health problems to humans and animals. In recent years, a number of investigations about the seroprevalence of T. gondii in China have been reported, but little is known on the prevalence of toxoplasmosis in sheep in northern China. In the present study, a total of 288 sheep serum samples were collected from Inner Mongolia, Heilongjiang, Jilin and Hebei provinces of northern China for T. gondii antibody survey using a latex agglutination test (LAT). Of these, 87 (30.2%) serum samples were positive for antibodies to T. gondii, and the antibody titres ranged from 1:64 to 1:1,024. Seroprevalence of T. gondii infection in sheep was 17.1% in Inner Mongolia, 33.8% in Heilongjiang, 24.6% in Jilin and 46.3% in Hebei. Age and rearing system significantly affected seropositivity. The present survey indicates antibodies to T. gondii are widely prevalent in sheep in northern China, which may cause public health problems in these provinces.

Molecular Detection of Theileria species in Cattle from Jilin Province, China

Bovine theileriosis is a tick-borne disease that is hampering the development of the domestic cattle industry in northern China. This study involved a molecular survey of bovine Theileria species in 137 blood samples from cattle in the Jilin province of China. The DNA samples were screened by species-specific 18S rRNA PCR. Results revealed that 19.7% (27/137), 17.5% (24/137) and 10.9% (15/137) were found to be infected with Theileria sinensis, Theileria orientalis, respectively. Mixed infection was found in 8.8% (12/137). The overall detection rates of Baishan, Yanji, Jilin and Liaoyuan districts was 60.0%, 17.5%, 5.3% and 0%, respectively. There is little information on the detection and distribution of bovine Theileria species in northern China. Therefore, this study provides important data for understanding the epidemiology of Theileria species and designing appropriate approaches for the diagnosis and control of bovine theileriosis in northern China.