Seroprevalence of Chlamydia Infection in Pigs from Intensive Farms in Southern China

Seroprevalence of Chlamydia abortus and Brucella spp. and risk factors for Chlamydia abortus in pigs from China

Chlamydiosis and brucellosis induced abortions have resulted in significant economic losses in the global livestock industry. Although there have been numerous reports on these two diseases in ruminants in China, limited information is available regarding the prevalence of Chlamydia abortus (C. abortus) and Brucella spp. infection in pigs. This study aimed to investigate the prevalence of C. abortus and Brucella spp. infections in pig serum using serology and to identify potential risk factors. In total, 2816 serum samples were collected from 12 provinces in China. The presence of C. abortus antibodies was determined using an enzyme-linked immunosorbent assay (ELISA), while the presence of Brucella spp. antibodies was examined using the Rose Bengal Plate Test (RBPT) and the Standard Agglutination Test (SAT). The seroprevalences of C. abortus and Brucella spp. were 8.38 % (236/2816) and 0.11 % (3/2816), respectively. Geographical location, season, and age were found to be risk factors associated with C. abortus infection in pig herds in China (p<0.01), and the seropositive rate for C. abortus in sow herds was strongly associated with the occurrence of abortion (p<0.01). Overall, in China, pigs exhibit a higher seroprevalence of C. abortus, whereas the prevalence of Brucella is limited. This study represents the first comprehensive survey of C. abortus and Brucella spp. in pig herds in China that established potential risk factors and provided data for the prevention and control of intraspecies and interspecies transmission of C. abortus to humans.

Detection of Insertions/Deletions Within SIRT1, SIRT2 and SIRT3 Genes and Their Associations with Body Measurement Traits in Cattle

Growth traits are complex quantitative traits controlled by numerous candidate genes, and they can be well-evaluated using body measurement traits. As the members of the nicotinamide adenine dinucleotide-dependent family of histone deacetylases, class I sirtuin genes (including SIRT1, SIRT2 and SIRT3) play crucial roles in regulating lipid metabolism, cellular growth and metabolism, suggesting that they are potential candidate genes affecting body measurement traits in animals. Hence, the objective of this work aimed to detect novel insertions/deletions (indels) of SIRT1, SIRT2 and SIRT3 genes in 955 cattle belonging to five breeds, as well as to evaluate their effects on body measurement traits. Herein, the novel 12-bp indel of SIRT1 gene, the 7-bp indel of SIRT2 gene and the 26-bp indel of SIRT3 gene were firstly reported, respectively. The association analysis indicated that the indels within SIRT1 and SIRT2 genes were significantly associated with body measurement traits such as body weight, chest circumference, height at hip cross, hip width, body height, etc. (P < 0.05 or P < 0.01). Therefore, based on these findings, the two novel indel variants within bovine SIRT1 and SIRT2 genes could be considered as potential molecular markers for growth traits in cattle selection practices and breeding.

First Report of Chlamydia Seroprevalence in Farmed Wild Boars in China

Chlamydia is Gram-negative obligate bacterium, which can cause human diseases worldwide and has huge economic impact on animals. It is yet to know whether farmed wild boars are infected with Chlamydia in China. To assess risk factors of Chlamydia infection in farmed wild boars in China, from April 2015 to February 2016, a total of 837 serum samples of farmed wild boars were collected in Jilin province, northeastern China, and antibodies against Chlamydia were examined by the indirect hemagglutination assay. The investigation showed that antibodies to Chlamydia were detected in 332 (39.67%, 95% CI 33.36-42.98) of 837 serum samples of farmed wild boars, seroprevalence ranged from 33.71% to 44.42% among different regions and the differences were statistically significant by SPSS analysis (p = 0.0248). These results indicated that Chlamydia is highly prevalent in farmed wild boars in Jilin province, northeastern China, and may pose a potential risk for human health. To our knowledge, this is the first report of Chlamydia seroprevalence in farmed wild boars in China, which provided baseline data for preventing and controlling Chlamydia infection in wild boars in China.

Chlamydia prevalence in Polish pig herds

Chlamydiae are frequently encountered intracellular Gram-negative bacteria. In pigs, these bacteria in combination with other pathogens contribute to the induction of a multi-aetiological syndrome. One of the major characteristics of Chlamydia spp. is their ability to cause prolonged, often subclinical infections. While the economic consequences of Chlamydia spp. infections in pig farms are not fully established, we know that reproductive disorders and other syndromes correlated with Chlamydia infection can lead to financial loss as a result of a reduction in pork production. Additionally, Chlamydia spp. presents a potential zoonotic hazard, therefore determining the prevalence of Chlamydia in pig populations is critical. In the present study 97 pig herds from Poland were involved. To determine the prevalence of Chlamydia PCR and CFT tests were used. In total 797 vaginal samples, 797 conjunctival samples, and 235 serum samples were collected and tested. The study took place from 2011 to 2014. We found Chlamydia spp. present in 71·2% of all tested farms. The percentage of animals testing positive on any given farm varied from 20% to 100%.

High-resolution genetic linkage mapping, high-temperature tolerance and growth-related quantitative trait locus (QTL) identification in Marsupenaeus japonicus

The Kuruma prawn, Marsupenaeus japonicus, is one of the most promising marine invertebrates in the industry in Asia, Europe and Australia. However, the increasing global temperatures result in considerable economic losses in M. japonicus farming. In the present study, to select genetically improved animals for the sustainable development of the Kuruma prawn industry, a high-resolution genetic linkage map and quantitative trait locus (QTL) identification were performed using the RAD technology. The maternal map contained 5849 SNP markers and spanned 3127.23 cM, with an average marker interval of 0.535 cM. Instead, the paternal map contained 3927 SNP markers and spanned 3326.19 cM, with an average marker interval of 0.847 cM. The consensus map contained 9289 SNP markers and spanned 3610.90 cM, with an average marker interval of 0.388 cM and coverage of 99.06 % of the genome. The markers were grouped into 41 linkage groups in the maps. Significantly, negative correlation was detected between high-temperature tolerance (UTT) and body weight (BW). The QTL mapping revealed 129 significant QTL loci for UTT and four significant QTL loci for BW at the genome-wide significance threshold. Among these QTLs, 129 overlapped with linked SNPs, and the remaining four were located in regions between contiguous SNPs. They explained the total phenotypic variance ranging from 8.9 to 12.4 %. Because of a significantly negative correlation between growth and high-temperature tolerance, we demonstrate that this high-resolution linkage map and QTLs would be useful for further marker-assisted selection in the genetic improvement of M. japonicus.

Seroprevalence and genotype of Chlamydia in pet parrots in China

Parrots are one of the most popular pet birds in China, and can harbour Chlamydia which has significance for human and animal health. We investigated, by indirect haemagglutination assay, the seroprevalence of Chlamydia infection in four species of parrots, namely budgerigars (Melopsittacus undulatus), lovebirds (Agapornis sp.), cockatiels (Nymphicus hollandicus) and Alexandrine parakeets (Psittacula eupatria) that were collected from Weifang and Beijing cities, North China and explored the association between potential risk factors and chlamydial seropositivity. We further determined the genotype of Chlamydia in 21 fresh faecal samples based on the ompA sequence by reconstruction of phylogenetic relationships. Of the 311 parrots examined, 35·37% (95% confidence interval 30·06–40·68) were seropositive, and species, gender, age, season and geographical location were identified as risk factors. Two PCR-positive samples represented Chlamydia psittaci genotype A. The occurrence of C. psittaci genotype A in the droppings of two pet parrots in China suggests potential environmental contamination with Chlamydiaceae and may raise a public health concern.

Seroprevalence of Chlamydophila abortus infection in yaks (Bos grunniens) in Qinghai, China

Chlamydophila abortus is an important amphixenosis which in a wide range of animals, associated with reproductive disorders in yaks. In order to assess the prevalence of this infection in yaks in Qinghai, China, a cross-sectional study was carried out, and a total of 674 serum samples were collected from June to October 2012 in six counties, and antibodies to C. abortus were examined by indirect hemagglutination (IHA) test. The overall seroprevalence of C. abortus in yaks was 17.66 % (119/674), and the seroprevalence of antibodies to C. abortus in yaks ranged from 11.82 to 28.43 % among the six different areas, and the difference was statistically significant (P < 0.05). The seropositivity of C. abortus infection in different age groups varied from 16.33 to 18.49 %, and prevalence in yaks of ≥3 year (18.49 %) was slightly higher than that in yaks of <3 year, but the differences among the age groups were not statistically significant (P > 0.05). The seroprevalence of C. abortus infection in male yak (16.8 %) was slightly lower than that in females (17.85 %), and the difference was not statistically significant (P > 0.05). So far, this is the first systematic and comprehensive investigation of C. abortus infectionin in yaks in this area.

Seroprevalence of Chlamydia infection in pigs in Jiangxi province, south-eastern China

Chlamydia are Gram-negative obligate bacteria that cause a wide range of diseases in humans and animals. To assess the risk of zoonosis posed by pigs, a total of 920 serum samples were collected from pigs in 11 administrative cities in Jiangxi province, south-eastern China, and the seroprevalence of Chlamydia antibodies was investigated by an indirect haemagglutination assay. The pathogen-specific antibodies were detected in 539 (58.59 %) pigs with seroprevalence ranging from 33.33 % (Jingdezhen) to 90.91 % (Pingxiang) among different cities (P<0.05). The highest prevalence was found in pregnant sows (80.89 %, 127/157), followed by breeding boars (79.37 %, 50/63), suckling sows (77.01 %, 67/87), fattening pigs (69.32 %, 61/88) and non-pregnant sows (62.5 %, 180/288). Piglets had the lowest prevalence of 22.78 % (54/237). The seroprevalence of Chlamydia infection among different categories of pigs was also significantly different (P<0.05). These results indicate that Chlamydia is highly prevalent in pigs in Jiangxi province and our results indicate that the presence of Chlamydia exposure in pigs may pose a potential threat to human health.

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.

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.

Seroprevalence of chlamydial infection in dairy cattle in Guangzhou, southern China

Chlamydia spp. are obligate intracellular gram-negative bacteria that cause a wide range of significant diseases in humans and animals worldwide, resulting in significant economic losses. Chlamydial infection in cattle has been reported in many countries including China. However, there has been no survey of chlamydial infection of dairy cattle in Guangzhou, southern China. The objective of the present investigation was to examine the chlamydial seroprevalence in dairy cattle in Guangzhou, subtropical southern China by using an indirect hemagglutination assay (IHA). The overall seroprevalence of chlamydial infection in dairy cattle was 7.25% (29/400). Greater than or equal to eight-yr-old dairy cattle had the highest seroprevalence (10.34%), followed by those that were ≥ 6 years old or < 7 years old dairy cattle (10.20%), although there were no statistically significant differences among different groups (P > 0.05). Dairy cattle with 5 pregnancies had the highest seroprevalence (10.81%). These results indicate that chlamydial infection was present in dairy cattle in Guangzhou, subtropical southern China, and integrated strategies and measures should be executed to control and prevent chlamydial infection and disease outbreak in the study region.