Developments in biologicals最新文献

Sow reproductive life is influenced by lameness issues. It has been reported that up to 44 percent of sows have locomotive problems. To date, few genome scans or association studies have been conducted to look at genes controlling lameness and other gait traits. In addition to health problems associated with leg and bone disorders, the pig has been suggested to be a good model for human bone disorders. Hence, the present study examined 134 porcine genes affecting skeletal development, mineral metabolism and other candidate genes for single nucleotide polymorphism (SNP) discovery. Atotal of over 370 SNPs have been identified to date and are being mapped. These SNPs are also being investigated for their associations with gait and locomotion problems in approximately 2,000 commercial pigs scored for various leg and locomotion traits. The association analysis of 22 genes revealed that the genes CALCR, HDBP CALCA, MTHFR, OXTR, IHH, ANKH, LRCH1 and OPN were significantly associated with leg and body conformation traits which affect the health and productivity of pigs.

The imprinted gene insulin-like growth factor 2 (IGF2) carries out important functions in the development of placental mammals, during the embryonic and fetal stages and is located on bovine chromosome 29. The main aim of this study was to verify the occurrence of a polymorphism (C/T transversion) in exon 6 of the IGF2 gene in Gir and Nelore cattle, Zebu breeds of great economic importance in Brazil for dairy and beef production, respectively. A 193 bp fragment of bovine IGF2 exon 6 was amplified by PCR with specific primers for this region and digested with Mboll enzyme to analyze the polymorphic segment. In a total of 39 Gir animals (29 females and 10 males), the estimated frequencies of the C and T alleles were 0.42 and 0.58, respectively. The genotypic frequencies were 0.10 for CC, 0.26 for TT and 0.64 for CT. For 28 Nelore animals (17 females and 11 males), the estimated frequencies of the C and T alleles were 0.43 and 0.57, respectively. The genotypic frequencies were 0.18 for CC, 0.32 for TT, and 0.50 for CT. This is the first report of the occurrence of this polymorphism in these breeds. The polymorphic site can be a regulatory motif with functional significance to gene regulation of the IGF2 gene. This polymorphism could be used to investigate the allele-specific expression of the IGF2 gene, its epigenetic status, and its role in developmental, growth and reproductive traits.

Gene expression was compared between resistant and susceptible Perendale lambs that had either never been exposed to gastrointestinal nematode challenge (had a naïve immune system with respect to parasites) or had been naturally challenged on pasture with nematodes. Only a small number of genes were differentially expressed between the naive resistant and susceptible animals, but many genes were differentially expressed between the resistant and susceptible challenged animals. The differentially expressed genes were involved in a variety of biological processes, most notably the immune response, the stress response and gene regulation via chromatin remodelling. The transcriptional profiling experiments also detected gene expression differences in the Ovar-DQA1 gene between resistant and susceptible challenged animals. A null allele of this gene was demonstrated to be associated with susceptibility to gastrointestinal parasites in some, but not all populations. This allele is not thought to be causal for susceptibility.

Genetic differences in susceptibility to ticks (Rhipicephalus (Boophilus) microplus) are considerable in bovines. Here, mapping, association and gene expression approaches were employed to further advance our understanding of the molecular basis of tick resistance. A B. taurus x B. indicus F2 population was developed by Embrapa and 382 individuals were measured for parasitic load. Scanning of all chromosomes is in progress. Quantitative trait loci (QTL) for tick load were mapped to chromosomes 4, 5, 7, 10, 14, 18 and 23 out of the 20 chromosomes scanned and were dependent on the season in which the phenotype was scored. In the candidate gene approach, females from the genetic groups Nelore (NE--184), Canchim x Nelore (CN--153), Aberdeen Angus x Nelore (AN--123) and Simmental x Nelore (SN--120) were evaluated under natural infestation. Microsatellite markers close to the genes for interleukin 2 (IL2), interleukin 4 (IL4) and interferon gamma (IFNG) were analysed. Tick counts were associated with the marker for interleukin 4 (P < 0.05) in three genetic groups. Differences in cytokine mRNA levels of naive versus infested Nelore calves as well as between resistant versus susceptible cows from NE, CN and AN genetic groups were also investigated. Comparison of cytokines from infested and naïve animals showed downregulation of IL2. When resistant cows were compared to susceptible animals, IL8 was downregulated. These results reinforce the multiloci nature of tick resistance and the need to consider QTL and environment interactions.

It is intriguing to note that RABV progression is interrupted neither by destruction of the infected neuron nor by the immune response. Thus, it is likely that RABV has developed a subversive strategy to avoid functional neuron impairment, which compromises the infectious cycle. Rabies virus neuroinvasiveness results from two factors: not only does neurotropic rabies virus avoid inducing neuronal cell death, but also 'protective' T cells that migrate into the infected nervous system are killed by apoptosis or inactivated, as a result of the overexpression of immunosubversive molecules such as FasL, HLA-G or B7-H1 in the infected nervous system. This suggests that the preservation of the neuronal network and the destruction of T cells that invade the nervous system in response to the infection are crucial events for rabies virus neuroinvasion and for transmission of rabies virus to another animal. Implications of these findings for rabies treatment are discussed.

Rabies is endemic in Iran. It is the most important zoonotic disease in the country. Based on studies undertaken during the past few decades, there is evidence that the main reservoir for rabies is wolves. The incidence of rabies in humans and animals is increasing each year. In 2006, more than 130,000 people received post-exposure prophylaxis. Similar figures apply regarding preventive vaccination in animals. Official data suggest that the majority of human exposures are due to biting episodes caused by dogs. However, investigations performed by this team showed that in many cases wolves were responsible for rabies transmission to humans. Because of the potential feasibility of oral rabies vaccination, this team has proposed a pilot study to evaluate the use of an oral rabies vaccine for vaccination of wildlife to control rabies in Iran.

Translocation has been used successfully by wildlife professionals to enhance or reintroduce populations of rare or extirpated wildlife, provide hunting or wildlife viewing opportunities, farm wild game, and reduce local human-wildlife conflicts. However, accidental and intentional translocations may have multiple unintended negative consequences, including increased stress and mortality of relocated animals, negative impacts on resident animals at release sites, increased conflicts with human interests, and the spread of diseases. Many wildlife professionals now question the practice of translocation, particularly in light of the need to contain or eliminate high profile, economically important wildlife diseases and because using this technique may jeopardize international wildlife disease management initiatives to control rabies in raccoons, coyotes, and foxes in North America. Incidents have been documented where specific rabies variants (Texas gray fox, canine variant in coyotes, and raccoon) have been moved well beyond their current range as a result of translocation, including the emergence of raccoon rabies in the eastern United States. Here, we review and discuss the substantial challenges of curtailing translocation in the USA, focusing on movement of animals by the public, nuisance wildlife control operators, and wildlife rehabilitators.

This study evaluated rabies epidemiology in Far EastAsia. Questionnaires were sent by the OIE to Far East Asian countries and eight questionnaires were returned. Data were collected from these returns, as well as from recent publications, to gather information regarding rabies epidemiology in these countries. More than 29,000 human deaths were reported in 2006 in Far East Asia, representing more than 50% of all human rabies cases around the globe. There are only a few countries or regions from which no human rabies was reported in 2006 such as Japan, Singapore, South Korea, Malaysia, Hong Kong, and Taiwan. In many of these rabies endemic countries, the number of human rabies cases has not changed much during the past decade. The only country with a steady decline is Thailand, where the number of cases has decreased from around 200 to about 20 cases per year. The most dramatic changes were observed in China. Human rabies cases declined from around 5,000 cases per year in the 1980s to about 160 in the mid-1990s. However, these trends have since been reversed. A steady increase has been reported over the past 10 years with more than 3,200 cases reported in 2006. Although there are many factors that contribute to the epidemic or endemic nature of rabies in these countries, the single most important factor is the failure to immunize domestic dogs, which transmit rabies to humans. Dog vaccination is at or below 5% in many of these countries, and cannot stop the transmission of rabies from dogs to dogs, thus to humans. It is thus most importantforthese countries to initiate mass vaccination campaigns in dog populations in order to stop the occurrence of human rabies in Far East Asia.

In 2004, a teenager survived bat-associated rabies through the Milwaukee protocol (MP). This survivor and another patient with dog-associated rabies were found to have developed deficiencies of tetrahydrobiopterin (BH4) and associated neurotransmitters. BH4 is also essential for neuronal nitric oxide synthase (nNOS), so rabies is predicted to cause constriction of cerebral arteries. We assume that rabies virus, which almost exclusively targets neurons, would disproportionately affect cerebral over systemic perfusion by disrupting nNOS and lead to generalised cerebral artery spasm. Cranial artery vasospasm, therefore, was actively sought in two rabies patients, with the intention to specifically treat with BH4 and L-arginine when necessary. Flow velocities and resistive (RI) or pulsatility indices (PI) of middle cerebral arteries (MCA) were obtained by transcranial doppler ultrasound (TCD). A survival analysis of 8 attempts at the MP is presented. Of these, two cases are reported here. The first case is one child with bat-associated rabies who developed severe bilateral MCAspasm on hospital day (HD)-10 that responded to very low dose (0.2 mcg/kg/min) nitroprusside. The second case, a child with dog-associated rabies, developed spasm of MCA on HD-6 that responded to 6 mg/kg/day BH4. A second spasm with high RI (without cerebral oedema or increased intracranial pressure) responded to 20 mg/kg/day BH4 and 0.5 g/kg/dose L-arginine. Review of the TCD of the first child showed a similar second spasm seven days after first episode. Cerebral artery vasospasm occurred in the two children with rabies, but was clinically silent by standard monitoring. Spasm responded to drugs directed at the NOS pathway. Animal models for treatment of rabies are sorely needed to evaluate therapy.

A five year study (1995-1999) was conducted in Northern India to investigate epidemiological aspects of rabies in domestic animals. For this purpose, brain tissue samples were collected from rabies suspect animals including 231 dogs, 79 buffaloes, 46 cattle and 28 wild species. Out of the 384 rabies suspected cases, 56% were positive for rabies by fluorescent antibody test (FAT), the mouse inoculation test (MIT) and histopathological techniques. Variations in clinical signs of rabies were recorded for individual animals with significant differences observed between dogs and bovines with respect to hypersalivation, paralysis, recognition of owners and aggression. Likewise, differences in the clinical course of disease between cows and buffaloes regarding hypersalivation and micturition were observed. Rabies incidence was highest among adult male dogs and indicated a seasonal pattern with more rabies cases during certain months of the year (January to April, and August to November). Its impact on cow/buffalo rabies is discussed. Accumulated history records revealed that 78% of owned rabid dogs were not prophylactically vaccinated against rabies.