Emergence of a new arbovirus disease in Brazil. III. Isolation of Rocio virus from Psorophora Ferox (Humboldt, 1819)

A newly described flavivirus was responsible for a large encephalitis epidemic in S?o Paulo State, Brazil. The etiologic agent, Rocio virus, was isolated from human patients and sentinel mice. The natural history of the virus is unknown although presumed to be arthropod-borne. Rocio virus was isolated from a single pool containing 19 Psorophora ferox of 47 pools (283 specimens) of this species tested. The positive pool contained 16 deplete, 2 gravid, and 2 engorged mosquitoes. No isolations were made from 2183 pools of other species. The positive pool was collected during the year of the epidemic at the same approximate time and place where vertebrate isolations were made.     

The hamster as a secondary reservoir host of lymphocytic choriomeningitis virus.

Exposure of weaned hamsters to an environment contaminated with LCM virus shed by tolerantly infected mice led to short subclinical infections. If infection occurred in early pregnancy, the young appeared normal at birth but their tissues were highly infective. For two to three months their bites and urine were also highly infective. A viraemia did not persist long enough for successive vertical transmissions of the infection to be likely. However, the viruria persisted in most prenatally infected hamsters for at least eight months and under simulated field conditions was a potent virus source for contact infections, leading to further generations of prenatally infected young. In the absence of the natural reservoir host, such long-term carriers could have been a major factor in causing the build-up of infection in colonies of hamsters which, when purchased as household pets, led to a recent spate of human clinical infections in Germany and the U.S.A.     

A comparative study of agar overlay and standard tissue culture methods for isolation of enteroviruses.

A study was made of the isolation of enteroviruses from 62 cerebrospinal fluids and 141 autopsy specimens with standard fluid monolayer tissue culture methods and tissue cultures under agar overlay with and without added MgCl2 (0.025M). Sixteen virus isolations were made only by the overlay method, two only by the standard technique, and six by both procedures. Additional studies were carried out on 975 diagnostic specimens of various types with standard tissue culture methods and with primary rhesus kidney cells under agar overlay containing 0.025M MgCl2. Seventeen virus isolations were made only by the overlay procedure, 20 only by the standard tissue culture method, and 75 by both techniques. Since there were instances in which either the agar overlay or the standard method alone succeeded in isolating a virus, use of both types of procedures would be desirable to isolate as many enteroviruses as possible from clinical specimens.     

Epidemic Venezuelan equine encephalitis in North America in 1971: vector studies.

A major epidemic of Venezuelan equine encephalitis occurred in south Texas in the summer of 1971. More than 1500 equines died of VEE in Texas, and 110 human cases with no deaths were reported. Vector studies in south Texas and northern Tamaulipas revealed that the overall mosquito infection rates during the peak of the epidemic were about 1:100, one of the highest rates observed for a major epidemic. Mosquito infection rates of this magnitude could easily explain the intensity of VEE outbreaks in both equines and man. A total of 943 VEE virus isolations were made from mosquitoes. Eight of the 12 mosquito species found infected were implicated in the epidemic cycle of VEE for the first time. Sufficient laboratory and field evidence is available to prove that Psorophora confinnis was one of the primary vectors of VEE. The lack of laboratory evidence necessitates the use of the term "probable" primary vectors for other species apparently equally as involved on the basis of field infections; these include Aedes sollicitans, Aedes thelcter and Psorophora discolor. Eight other species from which less than 10 VEE virus isolations were made were considered auxiliary vectors. Mosquitoes of some species were tested individually; such tests showed 2-4% of the probable primary vectors to be infected. The first isolation of VEE virus of the epidemic was made from P. confinnis on June 28, 1971. Highest mosquito infection rates occurred during the week of July 5. Mosquito infection rates declined precipitously in the last 3 weeks of July 1971, signaling the end of the epidemic in the study area. One explanation for the decline was that equines, the principal epidemic hosts, were eliminated as a source of virus by death or by acquisition of natural or induced immunity. Mosquito control appeared to be effective in reducing the infected mosquito population while the immunization of equines with TC 83 VEE vaccine was accomplished. Quarantines appeared to be effective in restricting the VEE virus activity to south Texas. Undoubtedly all of the control measures contributed to stopping the epidemic. Continued VEE surveillance by various government and other agencies failed to reveal any further epidemic VEE activity in the US in 1972. Other arboviruses isolated during the VEE studies in south Texas included St. Louis encephalitis virus, and San Angelo subtype of the California Group. A virus of the Bunyamwera Group was also isolated from Palo Blanco, Tamaulipas.     

Rift Valley fever virus (family Bunyaviridae, genus Phlebovirus). Isolations from Diptera collected during an inter-epizootic period in Kenya.

A total of 134 876 Diptera collected in Kenya during a 3-year period were tested in 3383 pools for Rift Valley fever (RVF) virus. Nineteen pools of unengorged mosquitoes were found positive for RVF. All isolations were made from specimens collected at or near the naturally or artificially flooded grassland depressions that serve as the developmental sites for the immature stages of many mosquito species. The isolation of virus from adult male and female A. lineatopennis which had been reared from field-collected larvae and pupae suggests that transovarial transmission of the virus occurs in this species.     

Rift Valley fever virus (family Bunyaviridae, genus Phlebovirus). Isolations from Diptera collected during an inter-epizootic period in Kenya

A total of 134 876 Diptera collected in Kenya during a 3-year period were tested in 3383 pools for Rift Valley fever (RVF) virus. Nineteen pools of unengorged mosquitoes were found positive for RVF. All isolations were made from specimens collected at or near the naturally or artificially flooded grassland depressions that serve as the developmental sites for the immature stages of many mosquito species. The isolation of virus from adult male and female A. lineatopennis which had been reared from field-collected larvae and pupae suggests that transovarial transmission of the virus occurs in this species.     

人源性宫颈癌、子宫内膜癌、卵巢癌异种移植动物模型的建立

目的构建人来源的宫颈癌(cervical cancer,CC)、子宫内膜癌(endometrial cancer,EC)、卵巢癌(ovarian cancer,OC)人源性肿瘤异种移植动物模型,为研究和开发新药及个体化治疗提供实验模型。方法收集2018年2月至2019年4月新疆医科大学第一附属医院CC、EC、OC患者各5例的新鲜手术切除标本,移植至重度免疫缺陷(immunodeficiency,NOG)小鼠和非肥胖糖尿病/重症联合免疫缺陷(non-obese diabetes/severe combined immunodeficiency,NOD/SCLD)小鼠皮下,监测荷瘤小鼠体重和肿瘤体积,对长至500~1 000 mm^3大小的肿瘤进行传代移植,通过苏木精-伊红染色法(hematoxylin-eosin staining,HE)染色及免疫组化(immunohistochemistry,IHC)验证移植肿瘤组织与患者肿瘤组织的病理学一致性。结果本研究收集并移植15例CC、EC、OC肿瘤标本,成功构建CC、EC、OC PDX模型8例,建模成功率为53%。结论模型较好地保留了原发肿瘤的特征,为后续研究开发CC、EC、OC新的治疗方案、临床药物筛选以及个体化治疗提供了实验平台。     

Interim guidance for minimizing risk for human lymphocytic choriomeningitis virus infection associated with rodents

In May 2005, CDC received reports of four organ-transplant recipients with unknown illness. All were discovered to have been infected with lymphocytic choriomeningitis virus (LCMV) via a common organ donor. Epidemiologic investigation traced the source of the virus to a pet hamster purchased by the donor from a local pet store. LCMV testing of other rodents at the pet store revealed three other LCMV-infected rodents (two hamsters and a guinea pig), supplied by a single distributor (distributor A). Preliminary laboratory testing of hamsters from distributor A has identified an infection rate of approximately 3% among the animals sampled. The facility of distributor A is under quarantine until it can be documented as free of LCMV infection. This report provides background information on LCMV and interim guidance for the public on reducing risk for LCMV infection from pet rodents.     

Epidermal tissue as a primary site of replication of lymphocytic choriomeningitis virus in small experimental hosts.

When fresh urine from LCM tolerantly infected mice was applied to small areas of excoriated skin of guinea-pigs undiluted or diluted 10(-1), a high LCM infectivity developed in the local dermal tissue within 3 days and quickly spread to the lymphatic system. The skin at this site of infection became erythematous 10--12 days after infection and a few days later a rash was often seen in the hairless skin around the mammary teats. A viraemia was first detected at about 8 days after infection and persisted for at least 8 days, during which time a high infectivity titre in skin not only at the infection site but also distal to it suggested that there was a generalized active infection of the dermis. Infectivity in the tongue was simultaneously high and probably associated with erosions of the tongue tip seen a day or two later than the teat rash. In similar experiments in hamsters and rabbits, indications were again that lightly injured dermis was a primary site of virus replication. These observations should lead to the dermal route receiving greater attention as a potential route of infection of man when exposed to infectious excretions of reservoir hosts of arena-viruses.     

Isolations of African horse sickness virus from vector insects made during the 1988 epizootic in Spain

This paper describes the first isolations of African horse sickness virus (AHSV) from insects in Spain. Seven isolations of AHSV serotype 4 were made; four from Culicoides imicola a known vector of the virus elsewhere, two from mixed pools of Culicoides species not including C. imicola and one from blood engorged mosquitoes. Three further isolations of AHSV serotype 4 were also made from horses kept adjacent to the insect collecting sites. This work presents the first definitive identification of the vectors of AHSV in Spain during the 1987, 88 and 89 epizootics. Suggestions are also made concerning the significance of these findings with regard to the epidemiology of African horse sickness in Spain.     

Arbovirus surveillance in Rhode Island: assessing potential ecologic and climatic correlates

During 1995-2000, mosquitoes were collected from sites throughout Rhode Island and tested for the presence of arboviruses. Mosquito trapping was done weekly from June to October with CO2-baited light traps. In all, 186,537 mosquitoes belonging to 7 different genera were collected, of which Coquillettidia perturbans was most abundant. A total of 6,434 pools were processed for arbovirus isolation, from which 193 arboviral isolations were made. These included 109 Highlands J, 71 eastern equine encephalomyelitis, 1 California encephalitis serogroup, 2 Jamestown Canyon, 3 Cache Valley, and 9 Flanders viruses. Our isolations of Flanders virus represent the 1st reported occurrence of this virus in Rhode Island. After the 1999 sudden occurrence of the West Nile virus (WN) in the New York City area, a dead-bird surveillance program was started to test for this virus. Although no isolations of WN were made from mosquitoes, 87 virus isolations were made from a total of 330 wild birds tested. All the WN-infected birds were either American crows or blue jays. Isolation of WN from dead birds marked the 1st documented appearance of this virus in Rhode Island. Significant interannual variation of arbovirus activity in Rhode Island prompted us to examine if climate-associated factors such as rainfall and temperature correlate with virus activity. Total rainfall amounts from May to June were higher than normal in 1996 and 1998. These years showed significantly higher arbovirus activity. Deviations from normal temperature showed low correlation with arbovirus activity during the 6-year study period. Therefore, precipitation appeared to be more important than temperature in predicting arbovirus activity in Rhode Island.     

Retardation of experimental oral cancer by topical vitamin E

Forty-eight young male and female golden hamsters (Mesocricetus auratus) were divided into four groups of 12 animals each. The left buccal pouches of Group 1 and 2 animals were painted 3 times weekly with a 0.5% solution of 7,12-dimethylbenz(a)anthracene (DMBA) in heavy mineral oil for 7 weeks. At the end of this period, the left buccal pouches of Group 2 animals were painted 3 times weekly with vitamin E (DL-alpha-tocopherol, in pure form) for an additional 4 weeks. Group 3 animals were painted with vitamin E only, for 4 weeks. Group 4 animals were untreated controls. Group 2 animals demonstrated a significant delay in tumor formation in comparison with Group 1 animals. Gross observation revealed fewer and smaller tumors in the Group 2 animals; microscopic examination revealed smaller tumors with better cellular differentiation and less invasion. No tumors were observed in Group 3 and Group 4 animals. These observations were similar to those made in previous studies of oral carcinogenesis using systemic vitamin E to delay tumor formation.     

A study of the carcinogenicity of glycidol in Syrian hamsters.

The industrial chemical glycidol is a directly acting mutagen and a broadly acting carcinogen in rats. It was administered to Syrian golden hamsters (20 male and 20 female) by gavage of 12 mg twice a week for 60 weeks. The total dose per animal was 1.45 g or 20 mmol. Survival was not different from control hamsters treated with corn oil/ethyl acetate. Of the treated males, 9 had tumors and 13 of the treated females had tumors, some of which were adrenal cortex tumors seen in controls. More tumors were seen in the glycidol-treated hamsters than in controls, but the spleen was the only notable target organ and the number of animals with spleen hemangiosarcomas was small. Glycidol appeared to be less carcinogenic in hamsters than in rats or mice.     

Anthrax vaccine efficacy in golden Syrian hamsters

The efficacy of a licensed human anthrax vaccine (anthrax vaccine adsorbed, AVA) was tested in golden Syrian hamsters against a virulent Bacillus anthracis spore challenge. Groups of golden Syrian hamsters were vaccinated at either 0 and 4 weeks or 0, 4 and 8 weeks, then challenged subcutaneously (s.c.) at 10 weeks with spores of various B. anthracis isolates. Although ELISA and toxin neutralization assays demonstrated high titers, none of the AVA-vaccinated hamsters were protected from challenge or demonstrated a significantly extended time to death compared to that of control animals. The results of the study demonstrate that the golden Syrian hamster is not an appropriate model for investigating human anthrax vaccine efficacy.     

Beta-glucan fractions from barley and oats are similarly antiatherogenic in hypercholesterolemic Syrian golden hamsters

The cholesterol-lowering activities of oats and barley are commonly attributed to the beta-glucan fractions. Although beta-glucan is present in both grains and appears to be chemically similar, the effect of source on cholesterol-lowering activity has not been evaluated. In the present study, the antiatherogenic properties of beta-glucan concentrates from oats and barley were evaluated in Syrian golden F(1)B hamsters consuming a semipurified hypercholesterolemic diet (HCD) containing cholesterol (0.15 g/100 g), hydrogenated coconut oil (20 g/100 g) and cellulose (15 g/100 g). After a 2-wk lead-in period, control hamsters were fed the HCD, whereas experimental hamsters consumed HCD formulated to include beta-glucan (2, 4, or 8 g/100 g) by addition of beta-glucan concentrate prepared from oats or barley at the expense of cellulose. Compared with control hamsters, dose-dependent decreases that were similar in magnitude in plasma total and LDL cholesterol concentrations were observed in hamsters fed beta-glucan from either source at wk 3, 6 and 9. Compared with controls, liver cholesterol concentrations were also reduced (P < 0.05) in hamsters consuming 8 g/100 g oat or barley beta-glucan. In agreement with previously proposed mechanisms, total fecal neutral sterol concentrations were significantly increased (P < 0.05) in hamsters consuming 8 g/100 g barley or oat beta-glucan. Aortic cholesterol ester concentrations were significantly reduced (P < 0.05) in hamsters fed 8 g/100 g beta-glucan from barley or oats. Although aortic total cholesterol and cholesterol ester concentrations were significantly correlated with LDL cholesterol (r = 0.565, P < 0.004 and r = 0.706, P < 0.0001, respectively), this association could explain only half of the variability. This study demonstrated that the cholesterol-lowering potency of beta-glucan is approximately identical whether its origin was oats or barley.     

Use of a zwitterionic detergent for the preparation of an influenza virus vaccine: 2. Immunogenicity of Empigen-treated virus in animals

The immunogenicity of zwitterionic detergent-disrupted influenza virus vaccine preparations, intact virus vaccine and vaccine preparations obtained by treatment of the intact virus with Triton-X 100 or cetyl trimethyl ammonium bromide (CTAB) was studied in hamsters and mice. In all experiments the intact, inactivated virus vaccine induced greater serum haemagglutination-inhibiting (HI) and neuraminidase-inhibiting (NI) antibody titres than the detergent-disrupted preparations. The serum HI antibody responses induced in hamsters and mice by Empigen-, Triton-, or CTAB-disrupted vaccines were similar, although more highly purified Empigen-disrupted preparations elicited marginally lower immune responses. In both animal species, all vaccine preparations afforded a similar degree of protection against homologous virus challenge.     

Pulmonary function in normal and elastase-treated hamsters exposed to a complex mixture of olefin-ozone-sulfur dioxide reaction products

An elastase-induced emphysema model was utilized to determine if hamsters with preexisting lung disease were more susceptible to lung damage from air pollutant exposure. Male golden hamsters, divided into two treatment groups, were given a single intratracheal injection of either 6 units of porcine pancreatic elastase (EMP) or buffer (CNT). After a 4-week recovery period, equal numbers of each group were exposed 23 hr/day × 28 day to filtered air (AIR) or to the complex by-products from a dark phase reaction mixture of trans-2-butene, ozone, and sulfur dioxide (MIX). Lung function measurements on the elastase-treated groups showed changes consistent with mild emphysema. There were no significant differences in lung volumes or lung compliance between the AIR- and MIX-exposed animals. However, the nitrogen washout slope decreased (P < 0.05), and the diffusing capacity for carbon monoxide increased (P < 0.05) in both the CNT and EMP hamsters exposed to the MIX. The change in diffusing capacity was greater (P < 0.05) in normal hamsters than in hamsters with emphysema, and it is hypothesized that animals with impaired lung function had a decreased ability to respond to a pulmonary insult from the mix.     

茶对二甲基苯并蒽诱发金黄色地鼠口腔癌预防作用的研究

选用二甲基苯并蒽（ Ｄ Ｍ Ｂ Ａ）诱发的金黄色地鼠口腔癌模型,研究绿茶、茶色素和混合茶对口腔癌的预防作用,并探讨其防癌机制。试验设阳性对照组（局部涂０５％ Ｄ Ｍ Ｂ Ａ,每周３次,共１５周）、３个饮茶试验组（在涂 Ｄ Ｍ Ｂ Ａ２周前开始分别饮１５％ 绿茶、０１％ 茶色素和０５％ 混合茶至１５周实验结束）和阴性对照组（仅涂丙酮）。结果表明,与阳性对照组相比,绿茶、茶色素和混合茶组对平均瘤数目的抑制率分别为４２６％ 、５０８％ 和６７２％ ,平均瘤负荷抑制率分别为７９４％ 、８８５％ 和９５５％ ;在３组中以混合茶对口腔癌的抑制效果最强。在涂 Ｄ Ｍ Ｂ Ａ 后的第６、１０和１５周,３个茶试验组中均见到口腔上皮细胞微核形成,每核银染核仁组织区（ Ａｇ Ｎ Ｏ Ｒ）颗粒数目和表皮生长因子受体（ Ｅ Ｇ Ｆ Ｒ）的表达低于阳性对照组。表明饮茶对 Ｄ Ｍ Ｂ Ａ 诱发的动物口腔癌有明显的预防作用,而茶预防 Ｄ Ｍ Ｂ Ａ 引起的粘膜细胞 Ｄ Ｎ Ａ 损伤和抑制粘膜细胞增殖可能是其预防口腔癌的重要作用机制。     

莲房原花青素对二甲基苯芘蒽诱发金黄地鼠口腔癌的预防作用

目的:研究莲房原花青素总提取物(LSPC)对二甲基苯芘蒽(DMBA)诱发金黄地鼠口腔癌的预防作用。方法:用电喷雾电离质谱分析LSPC,及用100mg/(kgbw?d)LSPC灌胃金黄地鼠或涂布地鼠颊囊,以肉眼观察颊囊粘膜、体重及死亡率变化,以实验结束后被处死动物血清中MDA、GSH-PX、T-SOD值和口腔粘膜组织常规HE染色病理观察等为指标,研究LSPC的防癌作用。结果:LSPC含量>98%,含单体、二聚体、三聚体、四聚体原花青素和原花青素二聚体棓酸单酯和三聚体棓酸单酯,分子量范围为290~1154.3。口服和涂布LSPC对DMBA诱发金黄地鼠颊囊黏膜癌变均具有预防作用,且以涂布LSPC的预防效果较佳。     

Antigenic and biologic characteristics of Venezuelan encephalitis virus strains including a possible new subtype, isolated from the Amazon region of Peru in 1971.

Nine strains of Venezuelan encephalitis (VE) virus isolated from the Amazon region of Peru in 1971 were identified as antigenic subtype I based on plaque-reduction neutralization tests with four and 20 units of antibody. A tenth strain, 71D1252, was possibly a new subtype, but was related to subtypes I and III. Hemagglutinins of each strain made from infected mouse brains had optimals pHs of 6.2 and 6.4. Nine strains were pathogenic for adult hamsters and adult mice, but strain 71D1252 inapparently infected some adult hamsters and mice inoculated peripherally. Plaques of nine strains in Vero African green monkey kidney cell cultures were intermediate in size between representative epizootic and enzootic strains, but plaques of strain 71D1252 were small like epizootic strains.