Arboviruses in Italy

A brief review of the arboviruses isolated In Italy is presented and discussed. Some of the Arboviruses considered in this paper are endemic in the country and are transmitted by arthropods that play actually a role of vectors, (sand flyes, hard ticks and mosquitoes); other arboviruses, sporadically isolated, are potential agents of emerging human or zoonotic diseases.     

Arboviruses and epizootic viruses

Some viral diseases are transmitted to human by arthropods (arboviroses), or by animals (zoonoses). Among more than 500 arboviruses and epizootic viruses that are classified into seven families, only a few are responsible for zoonoses or cause severe human diseases. Infected patients may show an acute disease associated with different symptoms, ranging from high fever to encephalitis, pulmonary distress, and haemorrhages. Some diseases show one or more of these symptoms and the factors responsible for severe outcomes, either linked to the virus, or to the host, or to the vector, remain poorly understood. Arboviroses and zoonoses are emerging or re-emerging diseases that need a multidisciplinary effort to control the propagation of the infectious agent and the pathogenesis in infected patients. Some viruses could be used for bioterrorism attacks. In virology, studies on the interactions of the viruses with their vectors and vertebrate hosts and on the pathophysiology of the infections will allow a better prevention of these diseases.     

Detection ofBorrelia burgdorferi sensu lato andChlamydophila psittaci in throat and cloacal swabs from birds migrating through Slovakia

We have screened 91 migratory birds representing 32 species during the autumn of 2003 for the presence of the zoonotic pathogens Borrelia and Chlamydophila. Using polymerase chain reaction (PCR), B. burgdorferi sensu stricto was detected in cloacal swabs and, in two causes, also in throat swabs in 8 individuals (8.7 %) representing 7 birds species; B. garinii and B. afzelii were not detected. C. psittaci was detected only in cloacal swabs; 6 birds (6.6 %) from four species were found to be positive. The PCR products were sequenced and the sequences were compared phylogenetically with the gene sequences of 14 Chlamydophila strains retrieved from nucleotide databases; although the sequenced DNA was only 110 bp long, all obtained sequences created a new cluster with sublines branching from a position close to the periphery of the genus. All tested samples appear distinct within the known species and were most similar to C. felis or C. abortis.     

Arboviruses of coastal south-eastern Australia

During investigations of epidemic polyarthritis at Nelson Bay, New South Wales, 12 strains of Ross River virus, the causative agent, were recovered from pools of mosquitoes. In addition, the mosquito pools yielded 9 strains of the flavivirus Edge Hill, 4 strains of a bunyavirus, Gan Gan, 1 strain of an orbivirus Tilligerry, and 1 strain of an ungrouped probable arbovirus, Yacaaba. The latter 3 viruses were found to be antigenically distinct from previously recorded arboviruses. A case of epidemic polyarthritis probably contracted at Bawley Point, approximately 400 kilometres south of Nelson Bay on the south coast of New South Wales, is recorded. Mosquitoes collected in the nearby Termeil State Forest one year later yielded a strain of Ross River virus and 5 strains of a previously undescribed ungrouped togavirus, Termeil. The extent of arboviral activity in temperate coastal areas of south-eastern Australia was unexpected.     

Arboviruses associated with human disease in Australia

Mosquito-borne arboviruses are an important public health issue in Australia. The alphaviruses Ross River and Barmah Forest virus are widespread and active annually, and cause debilitating polyarthritis. The flaviviruses Murray Valley encephalitis, Kunjin and Japanese encephalitis virus are restricted in distribution and activity but may cause life-threatening illness, and dengue viruses are active in some areas.     

我国新分离虫媒病毒的初步鉴定

1990－1994年,从新疆地区的蚊、蜱和病人血清分离了多株病毒,为了明确这些病毒的分类地位,对其中的20株病毒进行了组织培养细胞感染实验和血清学检验,对部分毒株做了动物接种实验和理化性质鉴定。结果显示：20株病毒均可使BHK－21细胞病变（1－3天）,主要表现为细胞圆宿、聚集,融合,破碎,脱落等;致Vero细胞病变为2－4天;15株病毒致C6／36细胞病变（2－4天）,5株病毒对C6／36细胞连续观察7天未见细胞病变。11株病毒对乳鼠2－4天致死,对成年鼠2－5天致死。选取6株病毒进行理化性质鉴定,4株病毒（90260、91002、91004和91028）对5－氟脱氧尿苷耐受,对乙醚和酸敏感,提示为有膜RNA病毒;一株病毒（90265）对5－氟脱氧尿苷、乙醚和酸均敏感,提示为有膜DNA病毒;另一株病毒（9059）对5－氟脱氧尿苷耐受,对乙醚和酸也耐受,提示可能为无膜RNA肠道病毒。20株病毒中,17株病毒与甲病毒、乙型脑炎病毒和布尼亚病毒的特异性免疫腹水不反应,提示这些病毒中可能不存在甲病毒、黄病毒和布尼亚病毒;3株病毒（90260、91002和91004）只与甲病毒的特异性免疫腹水反应,与乙型脑炎病毒和布尼亚病毒的不反应,提示这三株病毒为甲病毒。     

Interference Among Group A Arboviruses

Interference among group A arboviruses is described which does not involve the mediation of interferon. Interference was observed only if the interfering virus had an advantage over the challenge virus, either in time or in multiplicity of infection. Adsorption, penetration, and uncoating of challenge virus did not appear to be inhibited, but the synthesis of infectious viral ribonucleic acid of the challenge virus was significantly retarded. It was shown with temperature-sensitive viruses or mutants that the replication of viral ribonucleic acid by the interfering virus was required to establish interference. A mechanism of interference based on a competition for replication sites or substrates is compared with other possible explanations.     

Study of rickettsioses in Slovakia. III. Experimental infection of Apodemus flavicollis Melch. by rickettsiae of the spotted fever (SF) group isolated in Slovakia.

Experimental studies of infection of Apodemus flavicollis, and for comparison of rickettsiaemia in Clethrionomys glareolus and of susceptibility and antibody formation in white mice, with rickettsiae of the SF group isolated in Slovakia, gave the following results: the species A. flavicollis reacted by the formation of antibodies on subcutaneous administration of rickettsiae, strain B, in an amount of 10(0.5) EID 50/0.25 ml, whereas the white mouse only in an amount of 10(2.5). Rickettsiae, strain B, administered in an amount of 10(3.5) EID 50/0.25 ml subcutaneously to A. flavicollis were found in smears from the liver and spleen of the inoculated animals up to the 25th day following infection, on detection by the isolation test on chick embryo yolk sacs in the spleen on day 5 and 7, in lymph nodes on day 7 and in the brain on day 15 following infection; on detection by the method of injecting suspension from the organs into the haemocoelom of ticks regularly in the spleen and liver up to the 10th day, in the brain, kidney and lymph nodes regularly up to the 15th and irregularly in the lungs also up to the 15th day, then regularly in the testes up to the 5th day and in the heart, blood and peritoneum up to the 3rd day after infection.     

ATP-bound states of GroEL captured by cryo-electron microscopy.

The chaperonin GroEL drives its protein-folding cycle by cooperatively binding ATP to one of its two rings, priming that ring to become folding-active upon GroES binding, while simultaneously discharging the previous folding chamber from the opposite ring. The GroEL-ATP structure, determined by cryo-EM and atomic structure fitting, shows that the intermediate domains rotate downward, switching their intersubunit salt bridge contacts from substrate binding to ATP binding domains. These observations, together with the effects of ATP binding to a GroEL-GroES-ADP complex, suggest structural models for the ATP-induced reduction in affinity for polypeptide and for cooperativity. The model for cooperativity, based on switching of intersubunit salt bridge interactions around the GroEL ring, may provide general insight into cooperativity in other ring complexes and molecular machines.     

The occurrence of walnut ringspot onJuglans regia L. in Slovakia

The properties of a virus causing walnut ringspot ofJuglans regia L. which had been identified by the visual examination of symptoms on leaves and fruits of walnut trees in Slovakia were studied. The virus was transmitted mechanically toChenopodium quinoa Willd.,Chenopodium amaranticolor Coste et Reyn.,Nicotiana clevelandii Gray,Phaseolus vulgaris L. cv. Bountiful. Purified virus was used for antiserum production. The thermal inactivation point of the virus lies between 48 and 50 °C and the dilution end-point between 10^-1 and 10^-2. The obtained antiserum had a titer 1:256. Virus isolates gave a positive immunological reaction with the Mircetich's antiserum against the cherry leaf roll virus obtained from walnut tree.     

Cryptosporidiosis in zoo and pet birds.

Cryptosporidiosis is recognized as a primary disease in commercially raised chickens, turkeys, and bobwhite quail. Little is known about cryptosporidial infections in zoo and pet birds, although, infections of the small intestines, proventriculus, respiratory tract, and kidneys have been reported. In the present study, we reviewed cases of cryptosporidial infections in zoo and pet birds submitted to the State Veterinary Diagnostic Laboratory, Auburn, Alabama for necropsy or histopathologic examination. We identified infections in cockatiels, white-lored euphonias, bronze mannikin finches, and Australian diamond firetailed finches. Infections in the cockatiels occurred mostly in the small intestine, but parasites were also observed in the esophageal glands, air sacs, and proventriculus of some birds. Separate cases of small intestinal and proventricular infections were identified in the white-lored euphonias. Cryptosporidial parasites were found only in the proventriculus of the bronze mannikin finches and Australian diamond firetail finches. No cases of renal cryptosporidiosis were observed. Co-pathogens or other disease conditions were present in all birds. The Cryptosporidium species responsible for causing proventricular infection in zoo and pet birds may be different from C. meleagridis and C. baileyi.     

A possible magnetic transducer in birds.

A growing body of evidence indicates that a variety of animals can sense the earth's magnetic field. The possibility that the transducer of the magnetic sense is a microscopic ferromagnet of the sort observed in certain bacteria is examined theoretically. Neither energy and response time considerations nor existing experimental evidence make such a transducer implausible.     

圈养雄性大熊猫尿中睾酮激素水平的测定

本文对圈养的两只雄性大熊猫尿中睾酮激素进行了测定与比较,结果表明该老龄大熊猫"菲菲"与壮年大熊猫"川川"在同一时期内尿中睾酮激素含量基本处于相同水平,两者没有显著差异.由此可见老龄雄性大熊猫"菲菲"仍具有繁殖能力.     

Microculture Plaque Neutralization Test for California Group Arboviruses

A microculture plaque neutralization test is described for California-group arboviruses that is as precise and quantitative as the standard test conducted in 60-mm petri dishes. It was shown that there was no significant between-panel or between-day variation in determinations and that a single pipette could be used for all serum-dilution levels within a titration without inoculum carry-over effect. The experimental protocol and statistical methods used produce 50% neutralization end points that meet the assumptions of parametric statistics. This permits the power and versatility of the analysis of variance to be exploited in testing for treatment effects in serological and immunological studies with viruses.