The effects of pretreatment with Cyclosporin A and Docetaxel before vitrification of porcine immature oocytes on subsequent embryo development.

In the present study, we attempted to improve the developmental competence of vitrified immature porcine oocytes by the preservation of mitochondrial properties using Cyclosporin A (CsA, inhibitor of mitochondrial membrane permeability transition) and Docetaxel (stabilizer of microtubules, hence mitochondrial distribution). In Experiment 1, Mitotracker red staining revealed reduced mitochondrial activity (MA) in vitrified/warmed oocytes at 0 and 22 h of in vitro maturation (IVM) compared with fresh ones. However, by at 46 h of IVM, MA levels in vitrified oocytes were similar to those in fresh control. Treatment of oocytes with CsA or Docetaxel improved MA at 0 h and 22 h of IVM compared with non-treated vitrified oocytes. However, there were no significant differences among groups in percentages of survival, maturation and embryo development after subsequent IVM and parthenogenetic activation. Nevertheless, a pretreatment with a combination of 10 µg/mL CsA and 0.05 µM Docetaxel improved the blastocyst formation of vitrified oocytes compared with non-treatment counterparts (11.2 ± 1.6% vs 5.9 ± 1.6%, P < 0.05). In conclusion, vitrification reduced mitochondrial activity in GV-stage oocytes during 0-22 h of IVM; however, it was normalized by 46 h IVM. Docetaxel or CsA pretreatment alone did not improve development competence of vitrified oocytes. However, pretreatment with a combination of CsA and Docetaxel could improve blastocyst formation rates.

Prevalence, genotyping and risk factors of Giardia duodenalis from dogs in Vietnam.

This study was carried out to determine the prevalence, genotypes/assemblages and possible risk factors associated with Giardia duodenalis infection in dogs in central Vietnam. A total of 209 dog fecal samples, randomly collected from private owned dogs (n=105) and dogs from stores (n=104), were examined for Giardia cysts by microscopy. Positive samples were genotyped by PCR-sequence analysis of ß-giardin and triosephosphate isomerase genes markers. Risk factors were studied using a structured questionnaire and collected data were analyzed by univariate and multivariate logistic regression analyses. Results indicated that the overall infection rate was 8.6% (18/209) with the detected parasites were belonging to the non-zoonotic assemblages C and D. Age, gender and origin of animals were the main risk factors associated with G. duodenalis infection in dogs under study. Occurrence of infection was more likely in young animals compared to old ones and in females compared to males. Dogs originated from stores were more prone to Giardia infection compared to private owned counterparts.

Prevalence and first genotyping of Giardia duodenalis in beef calves in Vietnam.

Little information is available on the epidemiology of Giardia duodenalis in beef cattle from Vietnam. This study was performed to determine the prevalence and genotypes/assemblages of G. duodenalis in native beef calves younger than 6 months in the region. A total of 412 calf fecal samples, randomly selected from 99 small-scale farms located in DacLac and KhanhHoa provinces, central Vietnam, were screened for the presence of G. duodenalis cysts using the zinc-sulfate flotation method followed by iodine staining. The overall prevalence on the sample and herd levels were 13.8% (57/412) and 42.4% (42/99), respectively. Molecular analysis in the ß-giardin and triosephosphate isomerase genes demonstrated the presence of only G. duodenalis assemblage E in the animals. Since assemblage E has been rarely reported in humans, the zoonotic risk in beef calves in the region appears to be minimal.

Prevalence and Genetic Characterization of Histomonas meleagridis in Chickens in Vietnam.

This study was performed to investigate the prevalence and to characterize the genetic diversity of Histomonas meleagridis isolates in chickens in southern Vietnam. A total of 194 chickens, randomly selected from 18 backyard and 18 commercial flocks, were screened for H. meleagridis infection using both macroscopic diagnosis and an 18S rRNA gene-based PCR method. Overall, 12.9% of birds, representing 19 flocks, showed gross lesions typical for histomonosis whereas 25.3% of the birds from 29 flocks were positive by PCR assay. Following initial diagnostic approaches, H. meleagridis-positive samples were further analyzed by sequencing three different genomic loci; the 18S rRNA, alpha-actinin1, and rpb1. Thirteen samples from 12 flocks were genetically identified as H. meleagridis, demonstrating a flock and sample prevalence of 33.3% and 6.7%, respectively. There was no significant difference in prevalence between different farm types, age groups, and seasonality. Genetic analysis demonstrated minor heterogeneity of Vietnamese isolates with 99% homology to H. meleagridis sequences from the database. This is the first survey of the prevalence and genetic characterization of H. meleagridis in chickens in Vietnam.

Molecular characterization of Cryptosporidium in pigs in central Vietnam.

Little information is available on the epidemiology of Cryptosporidium in pigs in central Vietnam. The aims of this study were to investigate the prevalence and to characterize the genotype distribution of Cryptosporidium isolates in pigs in this region. A total of 193 pig fecal samples were screened for the presence of Cryptosporidium oocysts using the modified Ziehl-Neelsen staining method, and 28 (overall prevalence 14.5 %) were identified as positive by microscopic observation. Positive samples were further analyzed by polymerase chain reaction amplification and sequencing. Genetic identification based on the 18S ribosomal RNA and 70 kDa heat shock protein genes revealed that pigs in Vietnam are infected with two species/genotypes (Cryptosporidium suis and Cryptosporidium pig genotype II). This study is the first molecular characterization of Cryptosporidium in pigs in Vietnam. The presence of these host-adapted species/genotypes suggests that pigs may not pose a significant public health risk in this area. More extensive studies are necessary to ascertain the zoonotic potential of Cryptosporidium in porcine hosts in Vietnam.

Prevalence and molecular characterization of Cryptosporidium in ostriches (Struthio camelus) on a farm in central Vietnam.

This study was performed to determine the prevalence and molecular characterization of Cryptosporidium in ostriches on a farm in Khanh Hoa province, central Vietnam. A total of 464 ostrich fecal samples were examined Cryptosporidium oocysts using the modified Ziehl-Neelsen staining method, and 110 (overall prevalence 23.7%) were identified as positive by microscopy. Prevalence of Cryptosporidium in animals of <45 days, 45-60 days, 61-90 days, 91 days-12 months and >12 months was 23.5% (16/68), 33.3% (22/66), 35.2% (68/193), 0 and 5.8% (4/69), respectively (p<0.05). The majority of positive samples scored as the 3+ level of intensity of infection were from 61 to 90 days ostriches. Molecular analysis in the 18S ribosomal RNA, 70 kDa heat shock protein and actin genes demonstrated the presence of only Cryptosporidium avian genotype II in ostriches in central Vietnam.

Molecular characterization of Cryptosporidium in native beef calves in central Vietnam.

The aims of this study were to investigate the prevalence of Cryptosporidium and to characterize the genotype distribution of Cryptosporidium isolates in native beef calves 2-6 months old in Dac Lac province, central Vietnam. The presence of Cryptosporidium oocysts was determined using the modified Ziehl-Neelsen staining method. The overall prevalence on the sample and herd levels were 18.9% (44/232) and 50% (20/40), respectively. Genotyping based on PCR and sequence analysis of the 18 S rRNA gene revealed occurrence of the two nonzoonotic species Cryptosporidium ryanae and Cryptosporidium bovis, with the former as a dominant species in the animals. The absence of the zoonotic species Cryptosporidium parvum in calves examined suggests that the native beef calves 2-6 months old in the study area are unlikely to contribute to human cryptosporidiosis transmission.

Prevalence of Fasciola in cattle and of its intermediate host Lymnaea snails in central Vietnam.

The aims of this study were to investigate the prevalence of natural Fasciola infections in both the definitive hosts (cattle) and the intermediate hosts (Lymnaea snails) in central Vietnam. A total of 1,075 fecal samples, randomly collected from cattle in Binh Dinh, Khanh Hoa, and Phu Yen provinces, were examined for Fasciola eggs by a sedimentation method. The overall prevalence of Fasciola was 45.3 %. A subset of the animals (235) was also screened for antibodies against Fasciola by an enzyme-linked immunosorbent assay. Overall, 46.3 % of these animals were shedding Fasciola eggs while 87.2 % were Fasciola seropositive. A lower prevalence of Fasciola was observed in calves ≤ 2 years of age (37.6 %) compared to that in cattle >2 years of age (53.7 %) (p < 0.05). The prevalence in the rainy season (50.8 %) was significantly different to that in the dry season (38.1 %) (p < 0.05). Of the 3.269 Lymnaea viridis and 1.128 Lymnaea swinhoei examined, 31 (0.95 %) and seven (0.62 %), respectively, were found to be infected with Fasciola. This appears to be the first epidemiological survey of the prevalence of Fasciola in cattle and snails in these three provinces in central Vietnam.

Prevalence and risk factors associated with Cryptosporidium oocysts shedding in pigs in Central Vietnam.

We investigated the prevalence and risk factors associated with Cryptosporidium oocysts shedding in pigs in Central Vietnam. A total of 740 single fecal samples collected from diarrheic and non-diarrheic pigs on 89 farms were screened by the modified Ziehl-Neelsen staining method. Prevalence at the animal and the farm levels were 18.1% (134/740) and 71.9% (64/89), respectively. Risk factors for the infection were identified using univariate and multivariate logistic regression analysis. The results revealed that age, sanitary condition and topography were significantly associated with oocyst shedding (P<0.05). Pre-weaned piglets were at the highest risk for infection, followed by post-weaners, sows and finishing pigs. Good sanitary conditions showed positive effects in decreasing oocysts shedding. Topographically, Cryptosporidium was more common in mountainous zone than that in coastal delta zone. There was an association between the occurrence of diarrhea and the level of Cryptosporidium oocyst excretion within infected pigs. This is the first epidemiological investigation of prevalence and risk factors of Cryptosporidium in pigs in Vietnam.

Prevalence and first genetic identification of Cryptosporidium spp. in cattle in central Viet Nam.

We investigated the prevalence of Cryptosporidium infection in relation to age and clinical status in cattle in the central region of Viet Nam. A total of 266 fecal samples from diarrheic and non-diarrheic cattle were examined by the modified Ziehl-Neelsen staining method. Prevalence of Cryptosporidium parvum type infections, those of the Cryptosporidium andersoni type, and mixed infection of both types was 33.5% (89/266), 5.6% (15/266), and 3.4% (9/266), respectively. The infection rate of 44.3% (35/79) of C. parvum in calves less than 6 months old was significantly higher than that of 28.9% (54/187) in cattle greater than 6 months old (P<0.01). Although no C. andersoni oocysts were detected in calves less than 3 months old, no significant difference was observed between the age groups in the prevalence of C. andersoni infection and mixed infection. The percentage of diarrheic and non-diarrheic cattle identified to be shedding C. parvum oocysts was 46.5% (74/159) and 14.0% (15/107), respectively (P<0.0001). The risk of diarrhea was 1.7 times greater in C. parvum-infected calves than in their non-infected counterparts. DNA sequences of 18S rRNA genes of C. parvum type and C. andersoni type indicated that they were C. parvum bovine genotype and C. andersoni, respectively. This is the first genetic identification of C. parvum bovine genotype and C. andersoni from cattle in Viet Nam.