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Partners: serendipity in arbovirus research.

A review of 60 years of research on mosquito-borne arboviruses in the Western U.S.A. revealed a number of instances when serendipity influenced the development of new concepts or novel approaches to solve ecological or epidemiological problems. Eight such events were selected as examples. The need for effective mosquito traps to collect live mosquitoes to be tested for virus infection posed design problems and also led to the use of CO2 (dry ice) as a mosquito attractant. This research also led to identification of Culex tarsalis as a primary target for vector control programs in the western U.S.A. Attendance at a movie led to development of fluorescent dusts to mark mosquitoes for studies of their numbers, life tables and movements. Knowledge of vector-virus associations was used to influence state legislative action to provide funding for vector control and further discovery of vector-virus associations. Derivation of the term "Arbovirus" started as laboratory jargon and evolved into being the classification for over 500 vector-borne viruses. Sociobiological changes resulting from the use of television and air conditioning fortuitously decreased exposure of California residents to vector attack. These two changes were introduced into households in California in the early 1950s. The prime time when C. tarsalis, the primary vector of encephalitis, bites people is around sundown which also is primetime for television watching. These sociological changes are a valuable adjunct to vector control programs.

Animals↗

Immunoglobulin M antibody response to measles virus following primary and secondary vaccination and natural virus infection.

The use of IgM antibody detection for the classification of the primary and secondary measles antibody response in persons following primary and secondary vaccination and natural measles virus infection was examined. Of 32 nonimmune children receiving primary measles vaccination, 31 (97%) developed IgM antibodies, consistent with a primary antibody response. Of 21 previously vaccinated children with low levels of preexisting IgG antibodies who responded to revaccination, none developed detectable IgM antibodies, whereas 33 of 35 (94%) with no detectable preexisting IgG antibodies developed an IgM response. Of a sample of 57 measles cases with a prior history of vaccination, 55 (96%) had detectable IgM antibodies. Of these, 30 (55%) were classified as having a primary antibody response and 25 (45%) a secondary antibody response based on differences in their ratios of IgM to IgG antibodies. Differences in the severity of clinical symptoms between these 2 groups were consistent with this classification scheme. These findings suggest that 1) an IgM response follows primary measles vaccination in the immunologically naive, 2) an IgM response is absent on revaccination of those previously immunized, and 3) an IgM response may follow clinical measles virus infection independent of prior immunization status.

Adolescent↗

[Two virus strains of isolated in China are recombinant alphaviruses].

OBJECTIVE: To determine the classification, phylogenetic and genetic type of XJ-90260 and XJ-91006 viruses isolated in China. METHODS: Two pairs of specific primers were designed to amplify the NSP4 and E1-3' UTR genes of XJ-90260 and XJ-91006 viruses and the nucleotide sequences between them and with that of other Alphavirus were compared. RESULTS: The nucleotide sequences identity between XJ-90260 and XJ-91006 viruses was 100% and has showed the highest with WEE, comparing with the other 26 Alphaviruses in 3'-UTR. NSP4 gene of XJ-90260 and XJ-91006 viruses high homologous with EEE virus and E-1 gene high homologous wih SIN virus. XJ-90260 and XJ-91006 viruses belong to the B group of WEE and are closest to the Russian strain (Y62-33) by phylogenetic analysis. CONCLUSION: XJ-90260 and XJ-91006 viruses isolated in China are recombinant Alphaviruses, they belong to the same genetic type as WEE does.

Alphavirus↗

Evolutionary analysis of the picornavirus family.

An exhaustive evolutionary analysis of the picornavirus family has been carried out using the amino acid sequences of several proteins of the viruses including: the capsid proteins (1D, 1B, and 1C) situated at the 5' end of the genome and responsible for the serotype of the viruses, and the viral polymerase (3D), located at the 3' end of the genome. The evolutionary relationships found among the viruses studied support the new classification, recently suggested, in contrast to the classical one, and the existence of a new genus for the picornavirus family. In the new taxonomic organization, five genera form the picornavirus family: (1) aphthoviruses, (2) cardioviruses, (3) hepatoviruses (previously classified as enteroviruses), (4) renteroviruses (which mainly constitute a combination of the previous genera rhinovirus and enterovirus), and (5) a new genus, with a new and unique representative: the echovirus 22. Our analysis also allowed us, for the first time, to propose the most probable sequence of speciation events to have given rise to the current picornavirus family. The bootstrap procedure was used to check the reliability of the phylogenetic trees obtained. The application of the method of the statistical geometry in distance space to internal branches of the tree revealed a high degree of evolutionary "noise," which makes the resolution of some internal branching points difficult.

Capsid↗

Risk factors for infections in cirrhotic patients with and without hepatocellular carcinoma.

BACKGROUND: Patients with liver cirrhosis (LC) frequently have complications with bacterial infections, and these infections increase the mortality rate. However, a detailed analysis of infections associated with LC patients has not yet been performed. METHODS: We analyzed 325 patients with LC with and without hepatocellular carcinoma (HCC) who were hospitalized between 1997 and 1999. RESULTS: Infections developed in 70 (21.5%) patients and 48 (68.6%) of these developed infections during hospitalization. The mortality rate of 28.6% (20/70) in patients with infectious complications was higher than that of 12.5% (32/255) in patients without infectious complications. Forty (57.1%) of the 70 patients had infections of unknown causes; 11 (15.7%) had sepsis; 6 (8.6%) had intravenous hyperalimentation (IVH) infection; 3 (4.3%) each had spontaneous bacterial peritonitis (SBP), liver abscess, and cholecystitis; and 4 (5.7%) had other infections. Bacterial cultures of blood were prepared from 73 of the 325 patients (22.5%), and were positive in 22 of the 73 patients (30.1%). Of these 22 culture-positive patients, 11 had sepsis, 6 had IVH infection, 2 had liver abscess, 1 had cholecystitis, 1 had pneumonia, and 1 had decubitus ulcer. Gram-positive bacterial strains were detected most frequently, in 16 of the 24 strains isolated. Univariate analysis revealed significant differences between the groups with and without infectious complications with regard to hepatitis B virus infection, Child-Pugh classification, ascites, esophageal varices, survival rate, total-bilirubin (T-Bil), albumin (Alb), lactate dehydrogenase (LDH), total cholesterol (T-chol), and prothrombin time (PT). On multivariate analysis, the Alb level was selected as a significant independent factor contributing to the development of infections. CONCLUSIONS: Patients with advanced cirrhosis with low Alb levels should be carefully treated, and the administration of broad spectrum antibiotics covering gram-positive bacteria needs to be considered in the treatment of infections.

Age Distribution↗

Cetacean morbilliviruses are phylogenetically divergent.

We performed a phylogenetic comparison of porpoise morbillivirus (PMV) and dolphin morbillivirus (DMV) isolates from porpoises and dolphins respectively according to criteria adopted by the World Health Organization for the phylogenetic comparison of measles viruses. PMV and DMV were more divergent than the most distantly related measles virus strains, thus challenging the classification of PMV and DMV as two strains of a single species, cetacean morbillivirus.

Animals↗

Genomic evidence that simian virus 2 and six other simian picornaviruses represent a new genus in Picornaviridae.

Analysis of the VP1 capsid protein coding region of simian virus (SV) 2, SV16, SV18, SV42, SV44, SV45, and SV49 demonstrates that they are clearly distinct from members of the Enterovirus genus and from members of other existing picornavirus genera. To further characterize this group of viruses and to clarify their classification within the Picornaviridae, we have determined the complete genomic sequence of SV2 (8126 nucleotides). The genome was typical of members of Picornaviridae, encoding a single open reading frame. The putative polyprotein contained typical picornavirus protease cleavage sites, yielding mature proteins homologous to each of the known picornavirus proteins. SV2 contained an amino-terminal extension of the reading frame, which was analogous to the leader protein of members of the Aphthovirus, Cardiovirus, Erbovirus, Kobuvirus, and Teschovirus genera, but there was no significant amino acid homology with any of these known leader proteins. The 2A protein also aligned poorly with the 2A proteins of other picornaviruses. The deduced amino acid sequences of the SV2 structural and nonstructural proteins were related to but phylogenetically distinct from those of enteroviruses and human rhinoviruses. The major distinguishing features of SV2 were the presence of a type 2 internal ribosome entry site in the 5'-NTR, a putative leader protein encoded upstream of the structural proteins, and an unusually large 2A protein. On the basis of the molecular analysis, we propose that SV2, SV16, SV18, SV42, SV44, SV45, SV49, and porcine enterovirus 8 be classified as members of a new genus in Picornaviridae and that SV2 (strain 2383) be designated as the type strain.

5' Untranslated Regions↗

Genomic characterization of pestiviruses isolated from lambs and kids in southern Italy.

A nested polymerase chain reaction was used to identify 13 pestivirus strains isolated from small ruminants in several mixed (sheep and goats) flocks of Southern Italy, and for classification as bovine viral diarrhoea virus (BVDV) type 1, BVDV type 2, and Border disease virus (BDV) genotypes. Of the nine ovine isolates, two were characterized as BVDV type 1, and seven as BVDV type 2. The four pestiviruses isolated from kids belong to BVDV type 1. None of the pestivirus strains tested could be classified as 'true' BDV (genotype 3). Although BVDV type 2 has been described in Europe rarely, the characterization of BD/90-1M strain as BVDV type 2, isolated in Italy in 1990, demonstrates that this genotype has been circulating in Italy since the 1990s.

Animals↗

Effects of social support, stress, and level of illness on caregiving of children with AIDS.

The purpose of this descriptive correlational study was to explore the relationship between social support, stressors, level of illness, and perceived caregiver burden in caregivers of children with HIV/AIDS. Instruments used were: (1) the Classification System for Human Immunodeficiency Virus (HIV) Infection in Children Under 13 Years of Age (1987), (2) the Daily Hassles Scale, (3) the Tilden Interpersonal Relationship Inventory (IPRI), (4) the Derogatis Stress Profile (DSP), and (5) the Caregiver Appraisal Scale. The sample was drawn from two medical centers in New Jersey. The 49 caregivers of children with perinatally acquired HIV were predominantly HIV-positive biological mothers of African American descent whose education ranged from 8th grade through college. One-half of the children were classified at the CDC P2 level. Descriptive statistics and stepwise multiple regression were used to analyze the data. The results of the DSP indicated subjects were slightly below the 70th percentile for anxiety, depression, hostility, and work stressors and that subjects' social support levels were in the upper end of the low support category. Stepwise regression indicated that depression and anxiety predicted 40% of the variance in caregiver burden (R2 = .399; F = 14,985; p = .000). Hostility and level of social support predicted 37% of the variance in caregiving impact (R2 = .37; F = 13.254; p = .000). Finally, social support predicted 17.5% of the variability in the caregivers' sense of caregiving competency (R2 = .175; F = 9.788; p = .003). The child's level of illness and HIV status of caregiver did not significantly predict variance in caregiving appraisal.

Acquired Immunodeficiency Syndrome↗

Urolithiasis associated with indinavir in a patient with spinal cord injury.

OBJECTIVE: To report a case of indinavir-induced urolithiasis, and the greater risk of this occurrence in individuals with spinal cord injury (SCI) who require fluid restriction for an intermittent catheterization program (ICP). METHODS: Case report. RESULTS: A 38-year-old man with a T4 ASIA A SCI (according to the American Spinal Injury Association classification scale) and human immunodeficiency virus (HIV) infection was using an ICP and taking indinavir (a protease inhibitor) as part of his antiviral regimen. Cystoscopy was performed to rule out recurrent urethral condylomata. He was found to have a bladder stone measuring 0.5 cm x 0.5 cm x 0.3 cm, which, on analysis, was composed of indinavir (100% exterior, 90% interior). The bladder stone was removed under direct visualization. The plain abdominal radiograph did not reveal any stones. CONCLUSION: Indinavir is a frequently used drug for the treatment of HIV that has the potential to induce urinary lithiasis. This is particularly problematic for individuals with SCI who are on fluid restriction and an ICP. Therefore, cystoscopy and monitoring for indinavir-induced urolithiasis should be undertaken in individuals with SCI who are taking indinavir. Considerations include switching to a different protease inhibitor or choosing an entirely new HIV drug cocktail with less potential for urolithiasis.

Adult↗

Taura syndrome of marine penaeid shrimp: characterization of the viral agent.

The causative agent of Taura syndrome (TS) was recognized in 1994 to be viral in nature and tentatively classified as belonging to either the family Picornaviridae or Nodaviridae. The work reported here has led to a more definitive classification of this new penaeid virus. Located within the cytoplasm of infected cuticular epithelial cells of penaeid shrimp, the virus is a 31 to 32 nm icosahedral particle with a buoyant density of 1.338+/-0.001 g/ml. Three major (55, 40 and 24 kDa) and one minor (58 kDa) polypeptides constitute its proteinic capsid. Its genome contains a single molecule of ssRNA, which is polyadenylated at the 3' end and approximately 9 kb in length. Based on these characteristics, we believe that TS virus should be included in the family Picornaviridae. Ecuadorian and Hawaiian TS virus isolates were found to be identical in their biophysical, biochemical and biological characteristics, and should be considered as the same virus.

Animals↗

Tumor vascularity and lens culinaris agglutinin reactive alpha-fetoprotein are predictors of long-term prognosis in patients with hepatocellular carcinoma after percutaneous ethanol injection therapy.

Percutaneous ethanol injection therapy (PEIT) is now widely used for small hepatocellular carcinoma (HCC). However, only limited information is available regarding predictors of long-term prognosis of patients with small HCC after PEIT. The relationship of pretreatment clinicopathologic and biologic factors (age, sex, virus marker, Child-Pugh classification, tumor size, number of tumor, histologic grade, tumor staining, alpha-fetoprotein level, AFP-L3%, and Ki67 labelling index) to long-term prognosis in 41 patients with HCC were studied. Over-all survival rates of patients were 73.5% in 3-year, 34.7% in 5-year, and 27.0% in 7-year. Of the 12 variables investigated, Child-Pugh classification (p = 0.0243), histologic grade (p = 0.0098), tumor staining (p = 0.0012), AFP-L3% (0.0093), and Ki67 labelling index (p = 0.0467) were significantly associated with the long-term prognosis by univariate analysis. According to the multivariate analysis using Cox's proportional hazard model with step-wise method, tumor staining (p = 0.0024) and AFP-L3% (p = 0.0137) were significantly associated with the long-term prognosis after PEIT. In conclusion, the study found that positive tumor staining of HCC and positive AFP-L3% in serum were the predictor of poor prognosis in patients with HCC after PEIT.

Aged↗

Evidence of poxvirus in dusky dolphin (Lagenorhynchus obscurus) and Burmeister's porpoise (Phocoena spinipinnis) from coastal Peru.

In 1990, 74 dusky dolphins (Lagenorhynchus obscurus) and 10 Burmeister's porpoises (Phocoena spinipinnis) were examined for the presence of hyperpigmented marks and pinhole lesions on the skin (tattoo lesions) at the fishing terminal of Pucusana, central Peru. Prevalences of tattoo lesions were 8.1% and 30% in the dolphins and porpoises, respectively. Intracytoplasmic poxviruses were demonstrated by transmission electron microscopy in ultrathin sections of three of eight samples of infected epidermis from both species. The reason for the negative results in others is unclear but may be related to stages of infection with low virus density or even incorrect classification of some lesions as genuine viral tattoos. An irregular arrangement of tubules on the outer viral membrane, similar to those in orthopoxviruses, was visible in negative contrast preparations for P. spinipinnis. This is the first record of poxvirus in porpoises (Phocoenidae) and also the first report for dusky dolphins, and generally for cetaceans of the southern hemisphere.

Animals↗

Association of a new type of cytopathogenic myxovirus with infantile croup.

Viruses producing an unusual "sponge-like" cytopathogenic change in monkey kidney tissue culture were isolated from the pharyngeal swabs of 2 of 12 infants with croup. The infants from whom the viruses were isolated and 3 additional patients developed significant increases in neutralizing or hemagglutination-inhibition and complement-fixing or all 3 varieties of antibody during convalescence. The isolated agents appeared to be similar antigenically. Fluid from infected monkey kidney tissue culture agglutinated chick erythrocytes and in lower titer human "O" red cells. Hemagglutination occurred best at 4 degrees C. and pH 8.0. Agglutination was reversed at 37 degrees C. but resuspension and sedimentation of red cells at 4 degrees C. resulted in a restitution of positive patterns. In addition, the virus was capable of partially removing receptors from the erythrocyte surface, but only when large quantities of virus were incubated with red cells for 24 hours at 37 degrees C. and small doses of hemagglutinin used to test the treated cells. RDE removed both the erythrocyte receptors and the inhibitor for hemagglutinin present in certain normal sera. Low level multiplication occurred at a slow rate in the amniotic cavity of the fertile hen' egg. Gradocol membrane filtration yielded a size of 90 to 135 mmicro. The virus was stable at -70 degrees C. but infectivity was lost after treatment with 20 per cent ether for 15 hours. The properties of the isolated viruses were consistent with those required for classification in the myxovirus group. No antigenic relationship with influenza A, A', B, and C, Newcastle or Sendai viruses was found. The viruses were distinct from mumps virus but the existence of a common antigen was suggested. The high incidence of infection with this new virus in one group of croup patients suggests that it may be at least one of the etiologic agents of this clinical syndrome, but more extensive control studies will be necessary to establish a specific etiologic association. For the present the group will be referred to as CA viruses; i.e., croup-associated viruses.

Antigens↗

AIDS classification and the military.

In 1985 the U.S. Department of Defense took action to establish regulations for the protection of national defense personnel against the AIDS epidemic. Since that time specific procedures have been carried out in each military unit to effectively handle soldiers infected with the AIDS virus. A unique six-stage classification system for monitoring disease progression of AIDS is currently used in military medical facilities around the world, and military medicine remains active in the fight against AIDS.

Acquired Immunodeficiency Syndrome↗

Ethnostatistics and the AIDS epidemic.

Ethnostatistics is the study of the social practices surrounding the construction and interpretation of statistics. This paper considers certain ethnostatistical aspects of the official statistics on AIDS cases--the monthly updated figures on AIDS cases supplied by the Department of Health and derived from the English and Scottish voluntary reporting schemes. The paper focuses on problems in the classification of cases according to the route of virus transmission, particularly where multiple risk practices may be reported. Some (but not all) classification problems can be avoided by adopting a cross-tabular format of presentation. The data on reported Scottish AIDS cases are re-analysed in order to illustrate such a cross-tabular representation. These data are the basis for a concluding statement on the difficulties in projecting future heterosexual epidemic spread.

Acquired Immunodeficiency Syndrome↗

Association of human immunodeficiency virus (HIV) load early in life with disease progression among HIV-infected infants. New York City Perinatal HIV Transmission Collaborative Study Group.

The utility of RNA virus load to predict progression of human immunodeficiency virus (HIV)-1 disease was assessed in 89 HIV-1-infected children. Of 22 virus load values during week 1 of life, 17 were below the detection threshold. Geometric mean virus load increased to approximately 7 x 10(5) copies/mL by week 4, was sustained throughout the first 6 months of life, and then declined to 1.6 x 10(5) copies/mL during the third year. Samples from week 1 of life had little predictive value, but virus load during days 7-30 strongly predicted progression to CDC-3 classification or death (P = .024; risk ratio = 1.6), and virus load during months 2-3 predicted progression to CDC-C or death within the first 6 months of life (P = .002, risk ratio = 11). Virus load was highly associated with imminent vulnerability to CDC-C or death (P = .002) during the first 18 months of life. Except for values from the first week of life, virus load at any age through 18 months is strongly associated with risk of HIV disease progression.

Child, Preschool↗

Phylogenetic classification of human papillomaviruses: correlation with clinical manifestations.

Human papillomaviruses (HPVs) are a heterogeneous group of small dsDNA viruses which cause a variety of proliferative epithelial lesions at specific anatomical sites. Although more than 65 different virus types have been cloned and characterized, no uniform classification system exists. In order to classify HPV DNA types, phylogenetic trees were constructed based on nucleotide sequence alignments using parsimony and distance matrix algorithms. The resulting phylogenetic trees provide a classification of the HPVs into specific groups encompassing the known tissue tropism and oncogenic potential of each HPV type. The implications of a phylogenetic taxonomy on the diagnostic detection of HPVs and the concept of different HPV species are discussed.

Algorithms↗