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PubMed1978

Antibodies against arboviruses in postencephalitic and idiopathic Parkinson's disease.

Serum and CSF from patients with classic von Economo's postencephalitic Parkinson's disease, idiopathic Parkinson's disease and non-Parkinsonian neurological controls were tested for hemagglutination-inhibition antibodies to 17 arboviruses. All 35 CSF specimens from patients with idiopathic Parkinson's disease and controls were negative (ie, no inhibition of hemagglutination) with all the antigens. Of the total of 124 serums from the three study groups, 105 were also negative with all antigens tested. The only positive results were given by 19 serum specimens against one or more of group B arbovirus antigens, and/or against Batai and western equine encephalomyelitis antigens. There were no definitive differences in the distribution of these positive serum titers among controls, idiopathic Parkinson's, and postencephalitic Parkinson's cases. A causal relationship of the arboviruses tested with either the classical postencephalitic or idiopathic Parkinson's disease is not supported by the results of this study.

Antibodies, Viral↗
PubMed1998

Universal diagnostic RT-PCR protocol for arboviruses.

A selected number of PCR protocols were evaluated to determine if they could serve as a universal protocol for detecting and identifying all arboviruses. In this study, four parameters that affect the efficacy of RT-PCR (RNA extraction method, choice of reverse transcriptase, choice of DNA polymerase and thermocycling program) were evaluated in combination. The most optimal combination of those parameters employed use of silica gel membrane spin column, RAV-2 reverse transcriptase, Tth DNA polymerase, and a simple modification of a published thermocycling program. By this modified protocol, viral RNA could be amplified satisfactorily with more than 50 pairs of primers designed for diagnosis of arboviruses representing five families. The sensitivity and specificity obtained by this universal protocol were comparable to those obtained by the original protocol for each primer pair tested; and for some primers, improved sensitivity was observed. It was also found that a simple modification of a suggested protocol of a commercial RT-PCR kit could produce nearly identical results and serve as another universal protocol. With the use of a universal diagnostic reverse transcriptase-polymerase chain reaction (RT-PCR) protocol, simultaneous screening of clinical or biological specimens against a large number of RNA viruses belonging to many families can be performed more efficiently for etiologic determination in the situations complicated by the difficulty of differential diagnosis. Furthermore, such a universal protocol facilitates reducing the cost of PCR-based diagnostic operation and standardizing the qualities of PCR-based diagnosis within an institution or among collaborating institutions. A logical strategy is to conduct diagnosis in two stages by using broadly group-reactive primers in the first stage to narrow the range of possible etiologic agents and using virus-specific primers in the second stage for identification. Before such a strategy is employed, however, more group-reactive primers for a large number of arboviruses, for which no such primers currently exist, must be made available. Furthermore, the best pair or pairs of primers need to be selected for each virus for the second stage of the strategy.

Animals↗
PubMedDate not supplied

Continuous cell lines and immune ascitic fluid pools in arbovirus detection.

Successive experiments led us to use two cellular systems, MOS61 (Aedes pseudoscutellaris cells) and Vero cells, among the continuous cell lines recommended by the WHO Collaborating Center for systematic research and isolation of arboviruses. Virus detection in cell cultures is carried out with 7 mixtures containing 10 hyperimmune ascitic fluids made with the reference viruses. This technique enables the detection of 70 of the 80 arboviruses transmitted by mosquitoes in Africa and very easily detects arbovirus associations by using either monospecific or monoclonal immune ascitic fluids (dengue-1-2-3-4 and yellow fever viruses) used in the indirect immunofluorescence technique.

Aedes↗
PubMed1990

Establishment and characterization of a cell line from the mosquito Culex (Culex) theileri (Diptera: Culicidae) and its susceptibility to infection with arboviruses.

The mosquito Culex (Culex) theileri Theobald is probably the major vector of Rift Valley fever (RVF) virus during epizootics on the inland plateau of southern Africa. A cell line was established from the tissues of this mosquito species to facilitate laboratory studies on RVF and other arboviruses. After temperature pretreatment, egg rafts from a laboratory colony were disinfected, mechanically disrupted, and grown in preconditioned Eagles minimum essential medium supplemented with 10% fetal calf serum. The cells were characterized by their protein content, karyology, and their susceptibility to three arboviruses. Although high infectivity titers were obtained, no cytopathic effects were produced by these viruses. The cell line was shown to be free from latent viruses. These results show that this cell line may be employed fruitfully in arbovirus studies.

Animals↗
PubMed1975

Arbovirus infection of vertebrate and insect cell cultures, with special emphasis on Mokola, Obodhiang, and kotonkan viruses of the rabies serogroup.

Multiplication of rabies serogroup viruses, Obodhiang and kotonkan (two presumptive arboviruses), was induced in vertebrate cell cultures with Singh's A. albopictus cell cultures used as "helper cells" in cocultivation experiments. Plaque formation without prior in vitro adaptation was induced in Vero cell cultures with eight rabies serogroup viruses: in all five instances by cocultivation of either infected BHK-21 or A. albopictus cells with Vero cells under agar overlay and in three of eight instances by direct plaque assay of infected mouse brain suspensions. In cross-plaque reduction neutralization tests with cloned viruses that represented human pathogens, rabies, Duvenhage, and Mokola, on the one hand, and the presumptive arboviruses Obodhiang and kotonkan, on the other hand, Mokola virus shared common antigenic components with both the nonarboviruses and the arboviruses. Biologically, Mokola virus was different from the other two human pathogens, rabies and Duvenhage, in that it multiplied in both vertebrate and invertebrate cell cultures. Mokola virus thus appears to be the biologic and serologic bridging agent.

Aedes↗
PubMed1970

Preparation of noninfectious arbovirus antigens.

Noninfectious arbovirus antigens were prepared from borate-saline suspensions of infected suckling mouse brain buffered with tris(hydroxmethyl)aminomethane and treated with beta-propiolactone (BPL). The activity and stability of these antigens were enhanced by altering the buffering system, by passing the virus seed through a series of four or more continuous passages in the brains of suckling mice, or by a combination of these procedures. The titers of group A and B arbovirus antigens were comparable to titers of antigens extracted by the conventional sucroseacetone-BPL (SA-BPL) method. Antigens prepared from some ungrouped and Bunyamwera arboviruses by either the borate-saline-BPL or SA-BPL method produced inconsistent results and will require the development of more unique procedures to obtain suitable hemagglutinating antigens.

Animals↗
PubMed2004

Sucrose density gradient centrifugation and cross-flow filtration methods for the production of arbovirus antigens inactivated by binary ethylenimine.

BACKGROUND: Sucrose density gradient centrifugation and cross-flow filtration methods have been developed and standardised for the safe and reproducible production of inactivated arbovirus antigens which are appropriate for use in diagnostic serological applications. METHODS: To optimise the maximum titre of growth during the propagation of arboviruses, the multiplicity of infection and choice of cell line were investigated using stocks of Ross River virus and Barmah Forest virus grown in both mosquito and mammalian cell lines. To standardise and improve the efficacy of the inactivation of arboviral suspensions, stocks of Ross River virus, Barmah Forest virus, Japanese encephalitis virus, Murray Valley encephalitis virus and Alfuy virus were chemically inactivated using binary ethylenimine at a final concentration of 3 mM. Aliquots were then taken at hourly intervals and crude inactivation rates were determined for each virus using a plaque assay. To ensure complete inactivation, the same aliquots were each passaged 3 times in Aedes albopictus C6/36 cells and the presence of viral growth was detected using an immunofluorescent assay. For larger quantities of viral suspensions, centrifugation on an isopycnic sucrose density gradient or cross-flow filtration was used to produce concentrated, pure antigens or partially concentrated, semi-purified antigens respectively. RESULTS: The results of the propagation experiments suggested that the maximum viral titres obtained for both Ross River virus and Barmah Forest virus were affected by the incubation period and choice of cell line, rather than the use of different multiplicity of infection values. Results of the binary ethylenimine inactivation trial suggested that standardised periods of 5 or 8 hours would be suitable to ensure effective and complete inactivation for a number of different arboviral antigens. CONCLUSION: Two methods used to prepare inactivated arbovirus antigens have been standardised to minimise production failure and expenditure and to provide reagents that conform to the highest quality and safety requirements of a diagnostic serology laboratory. The antigens are suitable for use in either enzyme linked immunosorbent assays or haemagglutination inhibition assays and the optimised protocols can be directly applied to produce antigens from new or emerging arboviral pathogens.

Aedes↗
PubMed1975

Bertioga (Guama group) and Anhembi (Bunyamwera group), two new arboviruses isolated in São Paulo, Brazil.

Bertioga and Anhembi are two newly recognized arboviruses that were isolated in Saõ Paulo, Brazil. Bertioga was isolated from sentinel mice exposed in a forest of that name, and was shown to belong serologically to the Guama group of arboviruses. Anhembi, the second virus described, was isolated from pools of mosquitoes (Phoniomyia pilicauda and trichoprosopon pallidiventer), and from a spiny rat (Proechimys iheringi), and was shown to be a new member of the Bunyamwera group. The viruses are sensitive to sodium desoxycholate and are filterable through a millipore membrane of 450 mum pore size. Both are pathogenic for suckling mice and grow well in Vero cells, producing clear cytopathic effects. Detailed antigenic comparisons of Anhembi virus with other members of the Bunyamwera group isolated in the Americas, and of Bertioga virus with the members of the Guama group are presented. Both are believed to be new arboviruses in their groups.

Animals↗
PubMed2001

The growing threat of arbovirus transmission and outbreaks in Kenya: a review.

OBJECTIVE: To review the trend in arbovirus outbreaks and activity in Kenya in the last ten years. DATA SOURCE: Published reports of past outbreak investigations and more recent data available at the Arbovirology and Viral haemorrhagic fevers reference centre, Centre for Virus Research, Nairobi. STUDY SELECTION: Past and recent outbreaks and active transmission reports of arboviruses of medical importance in Kenya including Yellow fever (YF), Rift Valley Fever (RVF), Dengue and Crimean Congo haemorrhagic fever. SYNTHESIS: Each of the viruses was reviewed providing critical information on classification, incidence, outbreak, and activity in Kenya, mode of transmission, recognition of cases, management and control. CONCLUSION: There is increased frequency of outbreaks and detection of arbovirus activity in humans and vectors in the last ten years including re-emergence of YF virus as a public health concern in Kenya. The importance of recognition of cases and diagnosis (especially in malaria endemic areas) is critical to management and control. Effective countrywide surveillance backed by diagnostic centres is highly recommended.

Animals↗
PubMed2001

Arbovirus surveillance in South Carolina, 1996-98.

Arboviruses isolated and identified from mosquitoes in South Carolina (USA) are described, including new state records for eastern equine encephalitis virus (EEE), St. Louis encephalitis virus (SLE), Flanders virus, Tensaw virus (TEN), and a variant of Jamestown Canyon virus (JC). Mosquitoes were collected at 52 locations in 30 of 46 South Carolina counties beginning in June 1996, and ending in October 1998, and tested for arboviruses. Of 1,329 mosquito pools tested by virus isolation (85,806 mosquitoes representing 34 mosquito species or complexes), 15 pools were positive. Virus isolations included EEE from 1 pool each of Anopheles crucians complex and Culex erraticus; a variant of JC from 1 pool of An. crucians complex; a California serogroup virus from 1 pool of Aedes atlanticus/tormentor; TEN from 5 pools of An. crucians complex and 1 pool each of Culex salinarius and Psorophora ciliata; Flanders virus from 1 pool of Culiseta melanura; and Potosi virus from 1 pool each of Aedes vexans, Coquillettidia perturbans, and Psorophora columbiae. Of 300 mosquito pools tested by antigen-capture assay for EEE and SLE (14,303 mosquitoes representing 16 mosquito species or complexes), 21 were positive for EEE and I was positive for SLE. Positive EEE mosquito pools by antigen-capture assay included An. crucians complex (14 pools), Anopheles punctipennis (1 pool), Anopheles quadrimaculatus (1 pool), Cq. perturbans (4 pools), and Cs. melanura (1 pool). One pool of Cx. salinarius was positive for SLE by antigen-capture assay. Arbovirus-positive mosquito pools were identified from 12 South Carolina counties, all located in the Atlantic Coastal Plain, and from 4 of 8 Carolina bays surveyed.

Aedes↗
PubMedDate not supplied

Studies on the occurrence and distribution of HI antibodies against some arboviruses in the serum of domestic mammals in Puglia.

The virological and serological studies previously carried out on arboviruses in Italy are reviewed. The presence of antibodies to 11 arboviruses was investigated in the serum of various domestic animals (100 horses, 107 pigs, 102 sheep, 205 goats, 100 cattle and 200 dogs) from some areas of Puglia. The techniques are described. The results, given in tables and discussed in detail, support the hypothesis that in this region also there are arboviruses circulating, particularly those of group B.

Animals↗
PubMed1975

Arboviruses isolated from mosquitos and man in Surinam.

In the capital of Surinam, and in parts of the coastal plain and the savannah belt 47 strains of arbovirus were isolated from mosquito pools and from sentinel mice. Most of the strains (51%) were of the Mucambo type. The other types were Guama, Bimiti, Una, Catu, Restan, Maru, and Kwatta. Culex portesi was found to be the principal vector of all but one (Maru) types. Other vectors found to be carriers of arboviruses were Psorophora ferox, Mansonia venezuelensis, and Aëdes serratus. The highest proportion of mosquito pools yielding arboviruses was found in the savannah belt, the lowest in the municipality of Paramaribo.

Aedes↗
PubMed1988

[Arbovirus infections on the island of Nosy-Be; serologic and entomologic findings].

Since 1977, the Pasteur Institute of madagascar has been studying, during six surveys, the arboviruses of Nosy-Be area, in the north-west of Madagascar. 47.2 p. 100 out of 271 human sera and 11.3 p. 100 out of 150 animal sera (mostly from Lemurs), tested for antibodies to 16 arboviruses by the haemagglutination inhibition test, are positive. The results show an important prevalence of Flaviviruses. West-Nile and Dengue 1 viruses were probably circulating some years before the surveys. Antibodies against Sindbis and Rift Valley Fever viruses, were found only in few subjects. Bunyamwera and Tahyna viruses are absent. The rate of positive Lemurs is weak, particularly in Lemur macaco species. Flaviviruses are the most frequent. 12262 haematophagous diptera (11965 Culicidae belonging to 40 species) were caught . Aedes aegypti and Aedes albopictus are both present. Arbovirus isolation attempts from 394 mosquito pools failed; only Mengo virus was isolated from four pools of Erethmapodites quinquevittatus and one pool of Aedes (Skusea) sp.

Animals↗
PubMed1967

Survey for antibodies to arboviruses in the sera of children in Portuguese Guinea.

This paper describes the results of a study of antibodies to several arboviruses in representative groups of children in Portuguese Guinea. The survey was conducted in late 1964 and early 1965, in conjunction with a yellow fever vaccination programme undertaken when this disease appeared in West Africa. Sera were prepared from 1103 blood specimens collected from 10-15-year-old residents in different regions of the territory and were tested against 17 different antigens by means of the haemagglutination-inhibition test. In addition, 51 sera obtained from 20-25-year-old nonresidents were tested. The results show that group B arboviruses, particularly the yellow fever virus, were active in the region. Information on the activity of arboviruses of other groups was also obtained.

Adolescent↗
PubMed1981

Use of hyperimmune mouse ascitic fluids for arbovirus differentiation by indirect immunofluorescence and conventional serology.

The cross-reactivity of 22 arbovirus species (alphaviruses; tick- and mosquito-borne flaviviruses; and selected bunyaviruses) was tested with monovalent immune mouse ascitic fluids by indirect immunofluorescence (IIF) in comparison with classical serological reactions (virus neutralization -- VN; haemagglutination inhibition -- HI; and complement fixation -- CF -- reactions). Known relationships within the virus groups studied were confirmed. As to the differentiation limits, the VN test was followed by IIF. Evaluation of the ratio of heterologous to homologous antibody activities showed that with the exception of antigenically closely related arboviruses (Western equine encephalomyelitis -- Sindbis; Japanese encephalitis -- Murray Valley encephalitis; dengue viruses; California -- Tahyna), most arboviruses within the antigenic complexes tested could be relatively reliably differentiated by IIF.

Alphavirus↗
PubMed1996

Arbovirus titer variation in field-collected mosquitoes.

Patterns in the distribution of titers in arbovirus-positive mosquito pools were examined. Virus isolation records from the Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, from 1974 through 1993 were used to estimate virus titers in field-collected pools. Pools were classified as either low titer (< or = 3.0 log10 plaque-forming units [PFU]/ml) or high titer (> 3.0 log10 PFU/ml). The proportion of virus-positive pools that had high titers varied among the different domestic arboviruses, within viruses among field sites and years, and within viruses among mosquito species tested. Alphaviruses produced a greater proportion of pools with high titers than did the flaviviruses. Variation in the proportion of pools with high titers among sites and years suggested variation in mosquito and/or virus strains. Variation in the proportion of pools with high titers among mosquito species indicated species-specific differences in vectorial capacity. The results show that information about the titer of virus in mosquito pools can complement other parameters, such as the minimum infection rate, currently used in mosquito-based arbovirus surveillance programs.

Animals↗
PubMed1998

Probability model on the use of sentinel animal monitoring for arbovirus.

We specify the relations among the major parameters involved in using sentinel animals to monitor arbovirus transmission. By using probability models, first we demonstrate that vector density, infection rate, incubation period of sentinel animals, the number of sentinel animals used, and blood sampling frequency could directly affect the observed seroconversion rates and the comparison of these rates. Second, we evaluate the reliability of using sentinel animals to monitor arbovirus transmission under various conditions. On the basis of the model, we propose some measures for enhancing the reliability of using sentinel animals to monitor arbovirus. Third, we present a formula for estimating the number of sentinel animals used for a study designed to compare seroconversion rates. Fourth, we derive a necessary condition for deciding the blood sample frequency of sentinel animals. Fifth, we develop a formula that could be used to obtain the vector infection rate by using seroconversion data. Finally, we evaluate the epidemiology consequences of heterogeneous exposure of human hosts to vectors by theoretical modeling.

Animals↗
PubMed1964

STUDIES OF ARBOVIRUSES IN WESTERN AUSTRALIA. SEROLOGICAL EPIDEMIOLOGY.

In order to obtain information on the occurrence of arboviruses in Western Australia, sera from white persons and Australian aborigines and from animals were subjected to antibody estimations with selected viruses as a prelude to virus isolations. The serological evidence shows the presence of group A and group B arboviruses but significant differences in antibody distribution between the two groups. Antibodies to group A viruses, particularly to the Malayan mosquito virus AMM 2354, are present in both the aboriginal and the white populations over the entire territory. Neutralizing antibody to another group A virus, AMM 2021, isolated in Malaya, is found in much lower prevalence, while antibodies to the newly isolated Queensland group A virus, MRM 39, are found only in the Kimberley area. No avian group A antibodies were detected. The prevalence of group B antibodies is high in the northern part of the State and almost non-existent in the central areas. The results indicate the presence of more than one group B virus and the absence of dengue neutralizing antibody in the Australian aborigine. A unique situation exists in central Australia, where all aboriginal sera have group A antibody but none has group B antibody.

Animals↗