The rabies viruses of bats

In the 1930s rabies was shown to affect blood-, insect- and fruit-eating bats. We have prepared anti-nucleocapsid monoclonal antibodies (MAbs) using Mokola and bat (Lagos, Duvenhage and Denmark) rabies viruses as immunogens. With these MAbs we have examined rabies viruses from vampire, insectivorous and frugivorous bats from the Americas, Africa, Europe and the Soviet Union and have compared them with isolates from terrestrial species including man. As well as confirming the findings of others with viruses of African and American bat origin, the results revealed the presence of a second biotype in European bats and demonstrated the presence of serotype 1 as well as serotype 4 viruses in bats of the Soviet Union.     

Plasma fat-soluble vitamin and mineral concentrations in relation to diet in captive pteropodid bats.

Circulating plasma fat-soluble vitamin and mineral concentrations were compared in captive females of three species for fruit bats (Pteropus vampyrus, Pteropus hypomelanus, and Pteropus pumilus) fed the same diet. Daily total food intake averaged 28% of body weight on an as-fed basis or 7% on a dry matter basis. Dietary leftovers contained higher concentrations of phosphorus, magnesium, and zinc than the diet offered, suggesting some nutrient selectivity. Additionally, fecal mineral concentrations were two- to threefold higher than dietary concentrations of corresponding nutrients. Plasma concentrations of vitamin A (0.02-0.05 microg retinol/ml), vitamin D (1.50 ng 25-OH D3/ml; 93-108 pg 1,25 diOH D3/ml), and vitamin E (0.49-1.05 microg alpha-tocopherol/ml) were lower than in other herbivorous mammals, whereas plasma mineral concentrations were within normal mammalian ranges. These data may help assess the nutritional status of fruit bats.     

The porcine sperm reservoir in relation to the function of hyaluronan

The oviduct plays a role in successful animal reproduction not only in spermatozoa and ova transport to the fertilization site but also by affording a microenvironment for fertilization and early embryonic development. The sperm reservoir (SR) is restricted in the uterotubal junction (UTJ) and caudal isthmus. Billions of porcine spermatozoa are distributed to the female reproductive tract during/after insemination, and small amounts of them are stored for about 36–40 hours in the SR, which maintains sperm viability in the pre-ovulation period through its surface epithelium and production of fluid. The SR regulates the release of spermatozoa so that only a small population moves towards the fertilization site (ampulla) to decrease polyspermy. This review attempts to provide information about the structure and function of the porcine SR, its intraluminal content (hyaluronan, HA), and the influences of HA on porcine spermatozoa in vivo. In pigs, the spermatozoa are stored in a mucous-like fluid within the UTJ and caudal isthmus in the pre-ovulation period. The oviduct fluid contains sulfated glycosaminoglycans (GAGs) and non-sulfated GAGs, i.e., HA. It is interesting to note that HA is synthesized by hyaluronan synthase-3 (HAS-3), and its receptor, CD44, is found in the epithelium of the porcine SR site. Additionally, sperm capacitation does not occur in vivo in the SR during the pre- and peri-ovulation periods, but spermatozoa in the SR will attempt to capacitate if exposed to bicarbonate. However, capacitation in the SR will rise in the post-ovulation period, indicating the role of HA in modulating sperm capacitation after ovulation. All data support the understanding that the porcine SR ensures the viability of fertile spermatozoa and maintains the non-capacitated status during the pre-ovulation period. This basic knowledge about the SR is believed to be useful to advance sperm preparation procedures for in vitro fertilization (IVF) and improve the preservation process of porcine semen.     

The survival of some air-borne animal viruses in relation to relative humidity

The influence of relative humidity (R.H.) on the survival of the following viruses has been examined; feline herpesvirus (FHV); feline calicivirus (FCV); vesicular exanthema virus (VEV); infectious bovine rhinotracheitis virus (IBRV); parainfluenza 3 virus (PI-3 virus); vesicular stomatitis virus (VSV); equine herpesvirus type 1 (EHV-1), equine arteritis virus (EAV); equine rhinovirus (ERV-1), and African swine fever virus (ASFV). ASFV and PI-3 viruses survived well at all relative humidities when sampled 1 s after formation of an aerosol, but after storage of aerosols for 5 min both viruses were found to be sensitive to high R.H. The other lipid-containing viruses (EAV, VSV, FHV, EHV-1 and IBRV) were unstable when stored as aerosols in moist conditions. The picornavirus ERV-1 was the only virus which survived well at high R.H. but poorly on exposure to dry conditions. The caliciviruses VEV and FCV were sensitive to R.H. in the 30–70% range. When subjected to aeration, all of the lipid-containing viruses which were examined lost infectivity but non-lipid viruses, including bovine adenovirus type 1 (BAdV-1), were stable. The addition of 0.1% peptone reduced losses, probably by protecting against surface inactivation. The significance of these findings in relation to possible control measures for viral respiratory disease is discussed.     

Diagnostic investigation of emerging viruses of companion animals.

In this article, the authors are specifically concerned with the timely and accurate detection of emerging diseases of small animals that are viral in origin. Veterinarians are bound to encounter emerging viruses in their practice. The problem is unavoidable, because viruses are highly mutagenic. Even the immune response dictates the nature of virus that evolves in a host. If the clinical signs and diagnostic methods fail to correlate, the veterinarian should work with the diagnostic laboratory to solve the diagnostic puzzle.     

不同生态种群大银鱼生物特性的比较

对太湖产,天津产两个大银鱼生态群生态学特性比较结果：可数可量性状指标差异很小,属于同一品种;具有相似的生长规律,但太湖生态群的生长性能要优于天津生态群;从繁殖力指标分析,太湖生态群的繁殖力高于天津生态群,两种大银鱼生态种群具有相似的食性特征。     

Cytopathic bovine viral diarrhea viruses (BVDV): emerging pestiviruses doomed to extinction

Bovine viral diarrhea virus (BVDV), a Flaviviridae pestivirus, is arguably one of the most widespread cattle pathogens worldwide. Each of its two genotypes has two biotypes, non-cytopathic (ncp) and cytopathic (cp). Only the ncp biotype of BVDV may establish persistent infection in the fetus when infecting a dam early in gestation, a time point which predates maturity of the adaptive immune system. Such fetuses may develop and be born healthy but remain infected for life. Due to this early initiation of fetal infection and to the expression of interferon antagonistic proteins, persistently infected (PI) animals remain immunotolerant to the infecting viral strain. Although only accounting for some 1% of all animals in regions where BVDV is endemic, PI animals ensure the viral persistence in the host population. These animals may, however, develop the fatal mucosal disease, which is characterized by widespread lesions in the gastrointestinal tract. Cp BVD virus, in addition to the persisting ncp biotype, can be isolated from such animals. The cp viruses are characterized by unrestrained genome replication, and their emergence from the persisting ncp ones is due to mutations that are unique in each virus analyzed. They include recombinations with host cell mRNA, gene translocations and duplications, and point mutations. Cytopathic BVD viruses fail to establish chains of infection and are unable to cause persistent infection. Hence, these viruses illustrate a case of “viral emergence to extinction” – irrelevant for BVDV evolution, but fatal for the PI host.     

Viral networks and detection of potential zoonotic viruses in bats and rodents: A worldwide analysis

Bats and rodents are recognized to host a great diversity of viruses and several important viral zoonoses, but how this viral diversity is structured and how viruses are connected, shared and distributed among host networks is not well understood. To address this gap in knowledge, we compared the associative capacity of the host–virus networks in rodents and bats with the identification of those viruses with zoonotic potential. A virus database, detected by molecular methods, was constructed in the two taxonomic groups. We compiled 5,484 records: 825 in rodents and 4,659 in bats. We identified a total of 173 and 166 viruses, of which 53 and 40 are zoonotic viruses, in rodents and bats, respectively. Based on a network theory, a non‐directed bipartite host–virus network was built for each group. Subsequently, the networks were collapsed to represent the connections among hosts and viruses. We identified both discrete and connected communities. We observed a greater degree of connectivity in bat viruses and more discrete communities in rodents. The Coronaviridae recorded in bats have the highest values of degree, betweenness and closeness centralities. In rodents, higher degree positions were distributed homogeneously between viruses and hosts. At least in our database, a higher proportion of rodent viruses were zoonotic. Rodents should thus not be underestimated as important reservoirs of zoonotic disease. We found that viruses were more frequently shared among bats than in rodents. Network theory can reveal some macroecological patterns and identify risks that were previously unrecognized. For example, we found that parvovirus in megabats and Gbagroube virus in rodents may represent a zoonotic risk due to the proximity to humans and other zoonotic viruses. We propose that epidemiological surveillance programmes should consider the connectivity of network actors as a measure of the risks of dispersion and transmission.     

Biological properties of waterfowl-origin type A influenza viruses in chickens.

The replicative abilities and tissue tropism properties of 13 non-pathogenic or low-pathogenic waterfowl-origin type A influenza isolates recovered in 1986 were examined in chickens. Following intravenous challenge, reisolation of challenge virus was attempted from swabs of the luminal surfaces of the cloaca, jejunum, ileum, bursa, trachea, and air sacs and from swabs of bone marrow and liver tissues. Virus-isolation attempts were also accomplished on brain, thymus, spleen, pancreas, gonad, kidney, blood, and lung tissues. The overall frequency of influenza virus recovery for each experiment ranged from 3.1% to 49.3%. For all experiments combined, 58.3% of the kidney tissues and 62.9% of the cloacal swab samples collected on days 1 to 10 postinoculation were positive for challenge virus recovery. Virus titers up to 10(8.7) mean embryo infective dose per gram of kidney tissue were demonstrated in clinically normal chickens. Distinct biological variations and nephrotropism appear to exist among the corporate properties of virus populations making up each of the 13 waterfowl-origin type A influenza isolates.     

龙羊峡库区天然草地动态分析

利用美国陆地卫星T.M图象,对龙羊峡水库库区的天然草地进行了对比分析。结果表明,天然草地面积减少7084.09hm^2。其中减幅较大的为温性草原类和温性荒漠类,10年中分别减少了7299.27hm^2和1015.65hm^2。另外,草地盖度,牧草高度和草地产量也有下降,其中草地盖度下降5%-15%;牧草种数减少4-20种;牧草产量下降73.5-1090.05kg/hm^2。并对变化原因作了分析,提出了治理措施。     

1株H9N2亚型重组禽流感病毒的生物学特性

为研制高效特异的H9N2亚型AI疫苗,试验对利用反向基因操作技术构建的1株表面基因由A/chicken/Shanghai/10/01(H9N2)(简称SH10)提供、内部基因由12质粒系统提供的重组病毒SH/PR8的生物学特性进行了研究.结果表明,与亲本毒相比重组病毒的毒力有所下降,重组病毒在鸡胚上生长的适应性能更好,更适于作为新型疫苗株使用.     

表观健康鹅群新城疫病毒的分离及生物学特性

自江苏、山东、安徽3省不同地区的表观健康鹅群采集泄殖腔棉拭子样品,分离、鉴定新城疫病毒（NDV）,研究其生物学特性和分子流行病学特征,结果从1 108份样品中分离到11株NDV。依据鸡胚平均死亡时间（MDT）及融合蛋白（F）裂解位点氨基酸序列,判定其中6株病毒为NDV弱毒株,3株病毒为NDV中等毒力株,2株病毒为NDV强毒株。对F基因的序列测定及分析表明,6个弱毒株与La Sota株高度同源,3个中等毒力株与Texas GB株高度同源,2个强毒株则与1997年以来流行的对鹅具高度致病性的NDV有较高的同源性,只是其F蛋白信号肽序列及另外3个特征性位点的氨基酸显著不同。     

Avian influenza viruses in wild birds at the Jeziorsko reservoir in Poland in 2008-2010

During a 3-year surveillance study for avian influenza virus (AIV) infections at the Jeziorsko reservoir in central Poland, 549 oropharyngeal or cloacal swabs from 366 birds of 14 species belonging to 3 orders (Anseriformes, Charadriiformes and Gruiformes) were tested. AIV was detected in 14 birds (3.8%): Common Teals (12x), Mallard (1x) and Garganey (1x). Three potentially dangerous H5 AIV were detected in Common Teals (2x) and Garganey (1x) but all of them revealed a low pathogenic pathotype. A unique cleavage site amino acid motif PQREIR*GLF was found in one H5 isolate from a Garganey.     

松嫩平原天然肥披碱草种群生殖器官的数量性状分析

通过对混生群落肥披碱草大样本随机取样的调查与测定,定量分析了松嫩平原天然肥披碱草种群生殖器官的数量性状。统计结果表明,肥披碱草种群的穗状花序长为(15.55±2.13)cm,其生物量为(0.691 6±0.206 9)g/穗,子粒生物量为(0.527 5±0.164 1)g/穗,具有(26.63±3.35)个小穗/穗,(124.67±34.41)个小花/穗,(112.57±30.16)个子粒/穗,结实率为90.84%±6.23%。肥披碱草生殖器官各数量性状之间存在明显的变化规律,其中,小穗数/穗、小花数/穗、子粒数/穗随着穗长的增加均呈幂函数异速生长;生物量/穗随着穗长,子粒生物量/穗随着生物量/穗和小花数/穗的增加均呈线性同速生长。