Yanfang Lan

Tibial dyschondroplasia is highly associated with suppression of tibial angiogenesis through regulating the HIF-1α/VEGF/VEGFR signaling pathway in chickens

Tibial dyschondroplasia (TD) is an intractable poultry problem that is characterized by the appearance of non-vascularized and non-mineralized cartilage masses in tibial growth plates (TGPs). However, the role of angiogenesis inhibition in the occurrence of TD remains unknown. In this study, we found that, compared to low-altitude Arbor Acres chickens (AACs), high-altitude Tibetan chickens showed higher tibial vascular distributions that were accompanied by up-regulation of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor A (VEGFA) and VEGF receptors. These observations provide insights into hypoxia-induced angiogenesis, which may be related to the absence of TD in high-altitude native Tibetan chickens. Importantly, hypoxia experiments also showed that during hypoxia, tibial angiogenesis was enhanced, which was due to pro-angiogenic factor up-regulation (including VEGFA, VEGFR1, VEGFR2, and IL-8), in AACs. Moreover, we observed that thiram-induced TD could strongly inhibit tibial angiogenesis in the hypertrophic zone through coordinated down-regulation of HIF-1α and pro-angiogenic factors, leading to a disruption in the blood supply to the TGP. Taken together, these findings reveal that the occurrence of TD is highly associated with inhibition of tibial angiogenesis through down-regulated expression of HIF-1α, VEGFA and VEGF receptors, which results in suppression of TGP development.

High altitude hypoxia as a factor that promotes tibial growth plate development in broiler chickens

Tibial dyschondroplasia (TD) is one of the most common problems in the poultry industry and leads to lameness by affecting the proximal growth plate of the tibia. However, due to the unique environmental and geographical conditions of Tibet, no case of TD has been reported in Tibetan chickens (TBCs). The present study was designed to investigate the effect of high altitude hypoxia on blood parameters and tibial growth plate development in chickens using the complete blood count, morphology, and histological examination. The results of this study showed an undesirable impact on the overall performance, body weight, and mortality of Arbor Acres chickens (AACs) exposed to a high altitude hypoxic environment. However, AACs raised under hypoxic conditions showed an elevated number of red blood cells (RBCs) and an increase in hemoglobin and hematocrit values on day 14 compared to the hypobaric normoxia group. Notably, the morphology and histology analyses showed that the size of tibial growth plates in AACs was enlarged and that the blood vessel density was also higher after exposure to the hypoxic environment for 14 days, while no such change was observed in TBCs. Altogether, our results revealed that the hypoxic environment has a potentially new role in increasing the blood vessel density of proximal tibial growth plates to strengthen and enhance the size of the growth plates, which may provide new insights for the therapeutic manipulation of hypoxia in poultry TD.

Prevalence, Associated Risk Factors, and Phylogenetic Analysis of Toxocara vitulorum Infection in Yaks on the Qinghai Tibetan Plateau, China.

Toxocara vitulorum has been rarely reported in yaks at high altitudes and remote areas of Sichuan Province of Tibetan Plateau of China. The current study was designed to investigate the prevalence, associated risk factors, and phylogenetic characteristics of T. vitulorum in yak calves on the Qinghai Tibetan plateau. Fecal samples were collected from 891 yak calves and were examined for the presence of T. vitulorum eggs by the McMaster technique. A multivariable logistic regression model was employed to explore variables potentially associated with exposure to T. vitulorum infection. T. vitulorum specimens were collected from the feces of yaks in Hongyuan of Sichuan Province, China. DNA was extracted from ascaris. After PCR amplification, the sequencing of ND1 gene was carried out and phylogenetic analyses was performed by MEGA 6.0 software. The results showed that 64 (20.1%; 95% CI 15.8–24.9%), 75 (17.2; 13.8–21.1), 29 (40.9; 29.3–53.2), and 5 (7.6; 2.5–16.8) yak calves were detected out to excrete T. vitulorum eggs in yak calve feces in Qinghai, Tibet, Sichuan, and Gansu, respectively. The present study revealed that high infection and mortality by T. vitulorum is wildly spread on the Qinghai Tibetan plateau, China by fecal examination. Geographical origin, ages, and fecal consistencies are the risk factors associated with T. vitulorum prevalence by logistic regression analysis. Molecular detection and phylogenetic analysis of ND1 gene of T. vitulorum indicated that T. vitulorum in the yak calves on the Qinghai Tibetan plateau are homologous to preveiously studies reported.

Epidemiologic Survey of Japanese Encephalitis Virus Infection, Tibet, China, 2015.

We investigated Japanese encephalitis virus (JEV) prevalence in high-altitude regions of Tibet, China, by using standard assays to test mosquitoes, pigs, and humans. Results confirmed that JEV has spread to these areas. Disease prevention and control strategies should be used along with surveillance to limit spread of JEV in high-altitude regions of Tibet.

Prevalence of three Oesophagostomum spp. from Tibetan Pigs analyzed by Genetic Markers of nad1, cox3 and ITS1

Parasitic nematodes of Oesophagostomum spp., commonly known as ‘nodular worms’ are one of the most widely distributed and prevalent emerging zoonotic nematodes. However, little is known about the prevalence and gene characteristics of those parasites in Tibetan pigs. Therefore, a study was carried out to investigate the prevalence, isolation and identification of Oesophagostomum spp from Tibetan pigs by genetic markers of nad1, cox3 and ITS1 for the first time. The results revealed that the infection rate of O. dentatum and O. quadrispinulatum by genetic markers of nad1 was 81.13%; 35 (66.04%); the O. dentatum and O. quadrispinulatum by genetic markers cox3 was 66.04%, and O. dentatum and O. stephanostomum by genetic markers ITS1 was found to be 77.36%. Interestingly, the O. stephanostomum specie was identified and isolated from 90.48% stomach and 69.23% colon samples by genetic markers of ITS1. The present study, for the first time has described the presence and genetic characterization of Oesophagostomun spp of O. dentatum, O. quadrispinulatum and especially O. stephanostomum in Tibetan pigs from the high and remote Tibetan plateau. A public concern should be raised in terms of economical losses and severe public health problem.

Seroprevalence of Toxoplasma gondii infection in zoo and domestic animals in Jiangxi Province, China

Toxoplasma gondii is a zoonotic protozoan parasite that infects a wide range of warm-blooded animals throughout the world. In the present study, antibodies to T. gondii were determined using a commercial indirect hemagglutination (IHA) test in wild animals in a zoo. Three of 11 giraffes (Giraffa camelopardalis) (27%), 1 of 5 wolves (Canis lupus laniger) (20%), 1 of 6 hippopotamuses (Hippopotamus amphibious) (17%), and 2 of 9 tundra swans (Cygnus columbianus) (22%) were found to be positive. No antibodies were detected in leopards (Panthera pardus), wild geese (Anser cygnoides), and Eastern grey kangaroos (Macropus giganteus). Domestic species from 13 counties of Jiangxi Province, China were also investigated by an indirect hemagglutination (IHA) test. Thirty-five of 340 goats (10%), 94 of 560 water buffaloes (17%), and 4 of 35 cattle (11%) were found to be seropositive. This is the first report of T. gondii infection in animals kept in zoos and domestic animals in this province.

Seroprevalence of Toxoplasma gondii Infection in Wild Boars, Wild Rabbits, and Wild Chickens in Hubei Province, China

Toxoplasma gondii causes serious infection worldwide in humans and animals. In this study, the seroepidemiology of toxoplasmosis was investigated in wild boars (Sus scrofa) (n=377), wild rabbits (cape hare, Lapus capensis) (n=331), and wild chickens (red junglefwol, Gallus gallus) (n=571) in 4 forested and country sided area of Hubei province of China. For this, blood samples were collected and tested by indirect hemagglutination test (IHA). The seroprevalence was found to be 7.2%, 5.1%, and 12.6% in wild boars, rabbits, and chickens, respectively, with significant differences among these species. The prevalence of T. gondii infection in male and female wild boars was found to be 7.9% and 6.5% (P<0.01), in male and female rabbits was 5.6% and 4.9% (P<0.01), and in male and female chickens was 17.1% and 7.7% (P<0.01), respectively, with significant differences between 2 genders of chickens (P<0.01). The findings of this study may help in planning of the prevention measures against T. gondii infection in wild animals in this area.

Epidemiological Survey and Phylogenetic Characterization of Cysticercus tenuicollis Isolated from Tibetan Pigs in Tibet, China

Cysticercus tenuicollis, commonly known as “water bell,” is a larva of Taenia hydatigena, which is the most significant parasite of pigs. However, until now very few information is available regarding the prevalence and genetic characterization of the Cysticercus tenuicollis in Tibetan pigs. Therefore, the aim of this study was to investigate the prevalence and phylogenetic analysis of Cysticercus tenuicollis in Tibetan pigs. For this purpose, the COX2 gene of Cysticercus tenuicollis was amplified and sequenced for the first time in Tibetan pigs. The overall prevalence of Cysticercus tenuicollis was 43.93% in Tibetan pigs, with further distribution of 42.86% in 2014 and 45.35% in 2015. In Tibetan male and female pigs, the prevalence of Cysticercus tenuicollis was 43.39% and 44.56%, respectively. The prevalence of Cysticercus tenuicollis in different growing stages (juveniles, subadults, and adults) varied from 30.20% to 63.79%. The phylogenetic analysis of the Cysticercus tenuicollis isolates showed very close resemblance to 16 reference strains, isolates from Gansu, Hunan, and Sichuan provinces of China. To the best of our knowledge, this is the first report on the prevalence and genetic characterization of Cysticercus tenuicollis derived from Tibetan pigs. The data of present study provides baseline information for controlling cysticerci infections in pigs in Tibetan Plateau, China.

Seroprevalence and risk factors associated with hepatitis E virus infections among people and pigs in Tibet, China

Hepatitis E virus (HEV), the causative agent of hepatitis E, is an important public health problem throughout the world. There is little information available on the autochthonous HEV infection in highland inhabitants (Tibet, average elevation >3000m) of China. Therefore, we conducted a cross-sectional survey to determine the sero-prevalence of Hepatitis E and association of different risk factors in local people and pigs in Tibet, China. For this purpose, serum samples were collected from 600 local volunteers and 453 Tibetan pigs from July 2014 to August 2015. All the samples were examined for the presence of anti-HEV IgG antibodies by using enzyme-linked immunosorbent assay (ELISA). While socio-demographic and behavioral characteristics were also obtained through questionnaire. The present survey found a close relationship among the HEV of Tibetan people and pigs. The prevalence of anti-HEV IgG was detected 39.33% (236/600) and 42.38% (192/453) in local people and pigs, respectively. There was a significance association of different age groups, ethnic groups, people having contact with pigs or consuming uncooked meat, and gender of Tibetan pigs. Our findings confirmed the presence of autochthonous HEV among people and pigs in Tibet, China. Therefore, effective measures should be taken to prevent and control HEV infection in Tibet, China.

Effect of the acute heat stress on serum endotoxin concentration and the expression of TLR4 mRNA in liver of Arbor Acres broiler chickens

This study was undertaken to investigate the relationship between gut-derived endotoxin and the Toll-like receptor 4 (TLR4) expression in the liver of broilers under acute heat stress (AHS). For this purpose, 120 Arbor Acres chicks were randomised into two groups: control temperature group (CT group, 22 ± 1°C) and high temperature group (HT group, 38 ± 1°C). The chicks received AHS at Day 28 and their small intestine, liver and blood samples were collected after 2 h, 5 h and 10 h to examine the histopathology, biochemical parameters, endotoxin concentrations and TLR4 expression. The results showed that damaged intestinal villi and severe congestion of the hepatic sinusoids were observed, especially after 10 h of AHS in the HT group. In addition, the levels of alanine transferase, aspartate transaminase, and direct bilirubin, except alkaline phosphataseafter were significantly elevated (P < 0.05) and total bilirubin (P < 0.01) and albumin (P < 0.05) were decreased after 10 h of AHS as compared with the CT group, which are associated with liver function. Moreover, the mRNA expression of TLR4 in the liver was noticeably upregulated (P < 0.05) during AHS with significantly increased in endotoxin concentration (P < 0.01) of broilers. Altogether, these findings suggest that the upregulated expression of TLR4 mRNA was triggered via gut-derived endotoxin in heat stress-induced liver injury.