Development of a predictive model for ross river virus disease in Brisbane, Australia.
(25/97)
This paper describes the development of an empirical model to forecast epidemics of Ross River virus (RRV) disease using the multivariate seasonal auto-regressive integrated moving average (SARIMA) technique in Brisbane, Australia. We obtained computerized data on notified RRV disease cases, climate, high tide, and population sizes in Brisbane for the period 1985-2001 from the Queensland Department of Health, the Australian Bureau of Meteorology, the Queensland Department of Transport, and Australian Bureau of Statistics, respectively. The SARIMA model was developed and validated by dividing the data file into two data sets: the data between January 1985 and December 2000 were used to construct a model, and those between January and December 2001 to validate it. The SARIMA models show that monthly precipitation (beta = 0.004, P = 0.031) was significantly associated with RRV transmission. However, there was no significant association between other climate variables (e.g., temperature, relative humidity, and high tides) and RRV transmission. The predictive values in the model were generally consistent with actual values (root mean square percentage error = 0.94%). Therefore, this model may have applications as a decision supportive tool in disease control and risk-management planning programs. (+info)
Spatial-temporal analysis of Ross River virus disease patterns in Queensland, Australia.
(26/97)
Ross River virus is the most common vector-borne disease in Australia, with the majority of notifications being in Queensland. This study describes a retrospective spatial analysis of Queensland Ross River virus disease notifications spanning a 10-year period. Notifications were mapped to the local government area (LGA) of the residence of the patient. Ross River virus disease outbreaks within each LGA were detected by applying a Poisson model. Estimates of the seasonal incidence rates indicated wide variation between seasons and LGAs. Positive spatial autocorrelation between LGAs experiencing outbreaks indicated that LGAs within the same region often experience outbreaks at the same time. A hierarchical cluster analysis of the outbreak data was used to group LGAs with similar temporal outbreak patterns. This analysis highlights the variability in Ross River virus disease notification rates across Queensland, and provides a robust method for identifying disease outbreaks. (+info)
Human immunodeficiency virus type 1 vectors with alphavirus envelope glycoproteins produced from stable packaging cells.
(27/97)
Alphavirus glycoproteins have broad host ranges. Human immunodeficiency virus type 1 (HIV-1) vectors pseudotyped with their glycoproteins could extend the range of tissues that can be transduced in both humans and animal models. Here, we established stable producer cell lines for HIV vectors pseudotyped with alphavirus Ross River virus (RRV) and Semliki Forest virus (SFV) glycoproteins E2E1. RRV E2E1-stable clones could routinely produce high-titer pseudotyped vectors for at least 5 months. SFV E2E1-stable clones, however, produced relatively low titers. We examined the properties of RRV E2E1-pseudotyped vectors [HIV-1(RRV)] and compared them with amphotropic murine leukemia virus Env- and vesicular stomatitis virus glycoprotein G-pseudotyped vectors. HIV-1(RRV) displayed a number of characteristics which would be advantageous in ex vivo and in vivo experiments, including resistance to inactivation by heat-labile components in fresh human sera and thermostability at 37 degrees C. Upon single-step concentration by ultracentrifugation of HIV-1(RRV), we could achieve vector stocks with titers up to 6 x 10(7) IU/ml. HIV-1(RRV) efficiently transduced cells from several different species, including murine primary dendritic cells, but failed to transduce human and murine T cells as well as human hematopoietic stem cells (HSC). These results indicate that HIV-1(RRV) could be used in a number of applications including animal model experiments and suggest that expression of RRV cellular receptors is limited or absent in certain cell types such as T cells and human HSC. (+info)
Risks for Ross River virus disease in tropical Australia.
(28/97)
BACKGROUND: There are no analytical studies of individual risks for Ross River virus (RRV) disease. Therefore, we set out to determine individual risk and protective factors for RRV disease in a high incidence area and to assess the utility of the case-control design applied for this purpose to an arbovirus disease. METHODS: We used a prospective matched case-control study of new community cases of RRV disease in the local government areas of Cairns, Mareeba, Douglas, and Atherton, in tropical Queensland, from January 1 to May 31, 1998. RESULTS: Protective measures against mosquitoes reduced the risk for disease. Mosquito coils, repellents, and citronella candles each decreased risk by at least 2-fold, with a dose-response for the number of protective measures used. Light-coloured clothing decreased risk 3-fold. Camping increased the risk 8-fold. CONCLUSIONS: These risks were substantial and statistically significant, and provide a basis for educational programs on individual protection against RRV disease in Australia. Our study demonstrates the utility of the case-control method for investigating arbovirus risks. Such a risk analysis has not been done before for RRV infection, and is infrequently reported for other arbovirus infections. (+info)
Heparin binding sites on Ross River virus revealed by electron cryo-microscopy.
(29/97)
Cell surface glycosaminoglycans play important roles in cell adhesion and viral entry. Laboratory strains of two alphaviruses, Sindbis and Semliki Forest virus, have been shown to utilize heparan sulfate as an attachment receptor, whereas Ross River virus (RRV) does not significantly interact with it. However, a single amino acid substitution at residue 218 in the RRV E2 glycoprotein adapts the virus to heparan sulfate binding and expands the host range of the virus into chicken embryo fibroblasts. Structures of the RRV mutant, E2 N218R, and its complex with heparin were determined through the use of electron cryo-microscopy and image reconstruction methods. Heparin was found to bind at the distal end of the RRV spikes, in a region of the E2 glycoprotein that has been previously implicated in cell-receptor recognition and antibody binding. (+info)
Ross River virus disease reemergence, Fiji, 2003-2004.
(30/97)
We report 2 clinically characteristic and serologically positive cases of Ross River virus infection in Canadian tourists who visited Fiji in late 2003 and early 2004. This report suggests that Ross River virus is once again circulating in Fiji, where it apparently disappeared after causing an epidemic in 1979 to 1980. (+info)
An arthritogenic alphavirus uses the alpha1beta1 integrin collagen receptor.
(31/97)
Ross River (RR) virus is an alphavirus endemic to Australia and New Guinea and is the aetiological agent of epidemic polyarthritis or RR virus disease. Here we provide evidence that RR virus uses the collagen-binding alpha1beta1 integrin as a cellular receptor. Infection could be inhibited by collagen IV and antibodies specific for the beta1 and alpha1 integrin proteins, and fibroblasts from alpha1-integrin-/- mice were less efficiently infected than wild-type fibroblasts. Soluble alpha1beta1 integrin bound immobilized RR virus, and peptides representing the alpha1beta1 integrin binding-site on collagen IV inhibited virus binding to cells. We speculate that two highly conserved regions within the cell-receptor binding domain of E2 mimic collagen and provide access to cellular collagen-binding receptors. (+info)
Environmental predictors of Ross River virus disease outbreaks in Queensland, Australia.
(32/97)
Ross River virus (RRV) disease is the most common mosquito-borne disease in Australia, with the majority of cases reported from Queensland. In this study we investigate the relationship between local RRV disease outbreaks and standardized rainfall and temperature data in Queensland. No one set of variables could be found to accurately predict RRV disease outbreaks across all of Queensland, although good predictive models could be developed for smaller regions. The variables identified as important in predicting RRV disease outbreaks differed between regions, and also between summer and autumn. This work highlights the sensitive relationship between virus prevalence, mosquito bionomics, and climate, illustrating that critical climatic factors differ depending on underlying environmental conditions. Identification of factors leading to RRV disease outbreaks will help local authorities identify periods of high risk, optimizing the provision of additional mosquito control measures. (+info)