Observation of the excretion pattern of a precocious line of Eimeria necatrix and the strengthening of immune homogeneity.

The excretion frequencies of cecal and intestinal droppings of Chinese Lingnan yellow chickens were observed for 10 consecutive days. The chickens were then orally inoculated with a precocious line of Eimeria necatrix, and the oocysts present in the cecal and intestinal droppings were separately collected and monitored using the McMaster method. The results showed that the excretion frequency of cecal droppings was significantly lower than that of intestinal droppings, and the oocysts of E. necatrix were distributed primarily in the cecal droppings. This distribution affects the homogeneity of the second and third generation of oocysts ingested by the chickens and therefore affects the immune effect observed during E. necatrix immunization. To artificially strengthen the immunologic homogeneity against E. necatrix, a method of artificially strengthening the second immunization was applied, and the immune effect was evaluated based on oocyst excretion, body weight gain, fecal scores, intestinal lesion scores and survival percentages. The results showed that no significant intestinal damage was caused by immunization reactions in the chickens. In addition, the number of excreted oocysts in the immunized chicken groups could be significantly increased, and the immunologic homogeneity of the immunized chickens could be improved by artificially strengthening the second immunization, which could in turn improve the immune protective effect.

Chlamydia felis exposure in companion dogs and cats in Lanzhou, China: a public health concern.

BACKGROUND: Chlamydiaceae is a family of obligate intracellular pathogens with a worldwide distribution in many animal species, including humans. No information exists on the prevalence of Chlamydia felis infections in cats and dogs in Lanzhou, the geographical center of China. The aim of this study was to carry out a census of cats and dogs in Lanzhou and document the seroprevalence of C. felis exposure in these companion animals. RESULTS: In this study, blood samples were collected from 485 animals (221 cats and 264 pet dogs) in Lanzhou between November 2010 and July 2011 to identify antibodies against C. felis. Thirteen of 221 (5.9%) cats and 32 of 264 (12.1%) pet dogs were positive for C. felis infection using indirect hemagglutination at a cutoff of 1:16. The seroprevalence in household and stray cats was 3.9% and 14.3%, respectively, and the difference was statistically significant (P < 0.05). Among different age groups, the seroprevalence in cats varied from 1.9 to 7.9%, and that in dogs ranged from 9.6 to 20.4%; however, the differences were not statistically significant (P > 0.05). CONCLUSIONS: This is the first report of the seroprevalence of C. felis exposure in cats and dogs in Lanzhou, northwestern China. Our results indicate that the presence of C. felis exposure in cats and dogs may pose a potential threat to human health.

Seroprevalence of Toxoplasma gondii in beef cattle and dairy cattle in northeast China.

The seroprevalence of Toxoplasma gondii in beef cattle and dairy cattle in Heilongjiang Province, northeast China, was surveyed between April 2009 and May 2011. A total of 1803 (693 beef cattle and 1110 dairy cattle) serum samples were collected from 10 administrative regions rearing beef cattle and dairy cattle, and antibodies to T. gondii were examined by indirect hemagglutination (IHA) test. The overall seroprevalence of T. gondii in beef cattle and dairy cattle was 2.6% (46/1803), and the prevalence in beef cattle (3.0%) was slightly higher than that in dairy cattle (2.3%). The prevalence of antibodies in adult animals was higher than that in calves, but the differences among the age groups were not significant (p>0.05). The seroprevalence in female (3.4%) and male (2.5%) beef cattle was not statistically significant (p>0.05). Though the prevalence in intensively reared beef cattle and dairy cattle was lower than that in semi-intensively reared animals, the difference was not statistically significant (p>0.05). The results of this survey indicated the presence of T. gondii infection in beef cattle and dairy cattle in Heilongjiang Province, the coldest province in China, which may cause economic losses to the local livestock industry, and may be a source of T. gondii infection for humans in this region.

First report of Chlamydiaceae seroprevalence in Tibetan pigs in Tibet, China.

The seroprevalence of Chlamydiaceae infection in Tibetan pigs in Tibet, China, was examined by indirect hemagglutination assay (IHA), between April, 2010, and December, 2010. A total of 71 of 427 serum samples (16.63%, 95% confidence interval [CI] 15.31-17.95] were positive for Chlamydiaceae antibodies. Forty Chlamydiaceae seropositives from 232 samples were recorded in sera from Nyingchi (17.24%, 95% CI 15.40-19.08) and 31 positives were recorded in 195 serum samples from Mainling (15.90%, 95% CI 14.02-17.78). The investigation showed that the prevalence in female animals was 17.61% (95% CI 15.22-20.00), and in male animals it was 12.72% (95% CI 11.07-14.37). The prevalence ranged from 0% to 20.61% (95% CI 17.81-23.48) among different age groups, with a higher prevalence in growing pigs (p<0.01). The results indicated that Chlamydiaceae infection was widespread in Tibetan pigs in Tibet, China, which is of public health concern in this region of the world. To our knowledge, this is the first report of Chlamydiaceae seroprevalence in Tibetan pigs in Tibet, China.

Genomics and molecular genetics of Clonorchis sinensis: current status and perspectives.

Clonorchiasis caused by Clonorchis sinensis is an important foodborne parasitosis of humans and animals, and is predominantly a hepatobiliary disease. Globally, nearly 35 million people were infected with C. sinensis, with approximately 15 million being in China. Patients would chronically present fatigue, jaundice, abdominal discomfort, along with the increased risk of developing into a form of cholangiocarcinoma that is fatal to humans. Treatment of clonorchiasis by praziquantel has been very successful, but this is dependent on early accurate diagnosis and correct species identification. The present article reviews the current status of knowledge in genomics and functional genomics of C. sinensis, and summarizes the main DNA-based techniques for the specific diagnosis of C. sinensis infection and studies of genetic variation in C. sinensis, and provides perspectives for future studies. The advances in genomics and molecular genetics of C. sinensis shed new sight on our understanding of population structure of C. sinensis as well as the prevention and control of clonorchiasis.

First report of genotyping of Toxoplasma gondii isolates from wild birds in China.

Toxoplasma gondii is an important cosmopolitan opportunistic protozoan parasite, which threatens the health of human beings and animals. Genetic characterization of isolates from South America has revealed high genetic diversity. In contrast, isolates from North America and Europe were highly clonal, with 3 major lineages known as the Types I, II, and III. However, limited information on T. gondii genotypes has been reported in The People's Republic of China. Here we conducted a survey to determine genetic diversity of this parasite in wild birds of China. In total, tissues from breast muscle of 178 wild birds, including 98 common pheasants ( Phasianus colchicus ), 35 tree sparrows ( Passer montanus ), 22 house sparrows ( Passer domesticus ), 20 saxaul sparrows ( Passer ammodendri ), and 1 cinnamon sparrow ( Passer rutilans ), were tested for T. gondii infection, 4 of which were found to be positive for the T. gondii B1 gene by PCR amplification. These positive DNA samples were typed at 10 genetic markers, including 9 nuclear loci, i.e., SAG1, 5'- and 3'-SAG2, alternative SAG2, SAG3, GRA6, L358, PK1, c22-8, c29-2, and an apicoplast locus Apico. Of these, 3 isolates were genotyped with complete data for all loci, and 2 genotypes (Type I and Type II variant) were identified. This is the first report of genetic typing of T. gondii isolates from wild birds from different regions in China. The results suggest that the Type I and II variant strains are circulating in wild birds in China, and these birds are potential reservoirs for T. gondii transmission.

First report of Toxoplasma gondii infection in market-sold adult chickens, ducks and pigeons in northwest China.

BACKGROUND: Toxoplasma gondii infection is a global concern, affecting a wide range of warm-blooded animals and humans worldwide, including poultry. Domestic and companion birds are considered to play an important role in the transmission of T. gondii to humans and other animals. However, little information on T. gondii infection in domestic birds in Lanzhou, northwest China was available. Therefore, this study was performed to determine the seroprevalence of T. gondii infection in domestic birds in Lanzhou, northwest China. METHODS: In the present study, the seroprevalence of T. gondii antibodies in 413 (305 caged and 108 free-range) adult chickens, 334 (111 caged and 223 free-range) adult ducks and 312 adult pigeons in Lanzhou, northwest China, were examined using the modified agglutination test (MAT). RESULTS: 30 (7.26%) chickens, 38 (11.38%) ducks and 37 (11.86%) pigeons were found to be positive for T. gondii antibodies at the cut-off of 1:5. The prevalences in caged and free-range chickens were 6.23% and 10.19% respectively, however, statistical analysis showed that the difference was not significant (P > 0.05). The seroprevalences in caged and free-range ducks were 6.31% and 13.90% respectively, but the difference was not statistically significant (P > 0.05). CONCLUSIONS: The results of the present survey indicated the presence of T. gondii infection in adult chickens, ducks and pigeons sold for meat in poultry markets in Lanzhou, northwest China, which poses a potential risk for T. gondii infection in humans and other animals in this region. This is the first seroprevalence study of T. gondii infection in domestic birds in this region.

First report of Toxoplasma gondii prevalence in Tibetan pigs in Tibet, China.

Toxoplasma gondii infection is widely prevalent in humans and animals, including pigs throughout the world. In this study, the seroprevalence of T. gondii infection in Tibetan pigs in China was investigated for the first time. A total of 427 serum samples were collected from Tibetan pigs in Nyingchi prefecture, Tibet, between April and December 2010, and were assayed for antibodies to T. gondii using the modified agglutination test (MAT). Ninety-seven (22.72%) pigs were found to be positive with MAT titers of 1:25 or higher. Slaughter pigs had the highest seroprevalence, compared with seroprevalence in fattening pigs, growing pigs, or piglets, although the difference was not statistically significant (p≥0.05). The results of the present survey indicate that T. gondii is highly prevalent in Tibetan pigs in Tibet, which poses a significant public health concern in this unique region of the world.

Seroprevalence of Toxoplasma gondii infection in Tibetan sheep in Tibet, China.

In the present investigation, the seroprevalence of Toxoplasma gondii antibodies in 455 Tibetan sheep in Tibet, China, was examined using an indirect hemagglutination test. Of these, 26 (5.7%) Tibetan sheep were seropositive at the cut-off of 1:64 serum dilution. The seroprevalence ranged from 2.2% to 8.9% among Tibetan sheep of <1-yr-old, 1-3-yr-old, and >3-yr-old, but the differences among the age groups were not significant (P > 0.05). The prevalence in male Tibetan sheep (2.8%) was lower than that in female Tibetan sheep (6.6%), but the difference was not statistically significant (P > 0.05). The results of this survey indicated the presence of T. gondii infection in Tibetan sheep, which may cause economic losses to the local livestock industry and which poses a potential threat to human health in this area.

Seroprevalence of Toxoplasma gondii infection in household and stray cats in Lanzhou, northwest China.

BACKGROUND: Toxoplasma gondii is an important protozoan parasite infecting humans and almost all warm-blooded animals. As the only definitive host, cats play a crucial role in the transmission of T. gondii infection by shedding parasite oocysts in their feces. However, little information on T. gondii infection in cats was available in Lanzhou, northwest China. This study was performed to determine the seroprevalence of T. gondii infection in household and stray cats in Lanzhou, northwest China. RESULTS: A total of 221 (179 households and 42 strays) blood samples were collected from clinically healthy cats admitted to several pet hospitals located in Lanzhou City, between November 2010 and July 2011 for the serological detection of T. gondii infection. The majority (207) of these cats represented Chinese Lihua cats. 47 of 221 (21.3%) examined cats were seropositive for T. gondii infection using the modified agglutination test (MAT) at the cut-off of 1:25. The seroprevalence in household and stray cats was assessed to be 15.6% and 45.2%, respectively, and the difference was statistically significant (P <0.05). The seroprevalence ranged from 15.1% to 25.8% among different age groups, but the differences were not statistically significant (P >0.05). Studies showed that there was no relationship between seroprevalence and the gender (P >0.05). CONCLUSIONS: The present survey indicated the high seroprevalence of T. gondii in cats in Lanzhou, northwest China, which poses a threat to animal and human health. Therefore, measures should be taken to control and prevent toxoplasmosis of cats in this area.

Seroprevalence of Toxoplasma gondii infection in pet dogs in Lanzhou, Northwest China.

BACKGROUND: In recent years, surveys of Toxoplasma gondii infection in dogs have been reported worldwide, including China. However, little is known about the prevalence of T. gondii in pet dogs in Northwest China. In the present study, the prevalence of T. gondii in pet dogs in Lanzhou, China was investigated using the modified agglutination test (MAT). RESULTS: In this survey, antibodies to T. gondii were found in 28 of 259 (10.81%) pet dogs, with MAT titers of 1:20 in 14 dogs, 1:40 in nine, 1:80 in four, and 1:160 or higher in one dog. The prevalence ranged from 6.67% to 16.67% among dogs of different ages, with low rates in young pet dogs, and high rates in older pet dogs. The seroprevalence in dogs >3 years old was higher than that in dogs ≤1 years old, but the difference was not statistically significant (P >0.05). The seroprevalence in male dogs was 12.50% (17 of 136), and in female dogs it was 8.94% (11 of 123), but the difference was not statistically significant (P >0.05). CONCLUSIONS: A high prevalence of T. gondii infection was found in pet dogs in Lanzhou, Northwest China, which has implications for public health in this region. In order to reduce the risk of exposure to T. gondii, further measures and essential control strategies should be carried out rationally in this region.

Seroprevalence of Toxoplasma gondii in rats in southern China.

Toxoplasma gondii is widely distributed in humans and other animals, including wild rats throughout the world, but little is known of the prevalence of T. gondii in rats in China. The seroprevalence of T. gondii in rats ( Rattus norvegicus and Rattus flavipectus ) was investigated in Guangzhou, southern China, between November 2009 and January 2010. In total, 217 rat serum samples were collected; antibodies to T. gondii were detected by the modified agglutination test (MAT), and 7 (3.2%) were found positive (titers ≥ 1:40). The seroprevalence was higher (3.4%) in R. norvegicus than in R. flavipectus (3.0%), but the difference was not statistically significant (P > 0.05). All 7 positive rats were female; no T. gondii antibodies were detected in males. This is the first extensive survey of T. gondii infection in rats in southern China, and the results have public health implications in this region.