Ross River Virus Genetic Variants in Australia and the Pacific Islands

Abstract

Summarj. HaeHI andTaql restriclion digest profilesof cDNA to infected cell RNAor virion RNA were used as a guide lo gcnclic relationships between fouricen isolate of Ross River virus (RRV) obtained from mosquiiuescollccied in various localities in easiern Ausiralia where ihe virus '\s endemic. RRV isolates from t-iji. American Samoa, ihe Cook Islands and ihc W'allis Islands where major ouibrcaks of epidemic polyarthritis lonk place in 1979-19H0 were also examined.Among these RRV isolates we have identified three geneiic lypes (l-lil) on the hasis of differences between iheir restriction digest proHles. We estimate ihat IS-S^^o nucleoiide sequence diversity exists between genetic types. Within each genetic type strain dilTcrentiation gave rise to small but significant differences in restriction digest profiles.No clear pattern of geographic distribution of RRV genetic lypcs could bo established from the limited number of RRV isolates examined. Genetic types I. II and III, respocti\ei\. were isolated from three, three and one different mosquiio species, indicating there is no sirong association beiween geneiic type and thf species of mosquito vecior.Haelll restriction digest analysis did not detect any genetic difference between the four Pacific Island isolates, suggcstitig that a single RRV variani was involved tn ihe epidemics. Genetically, this variant was closely related to isolates of genetic type 11. Virtually identical Haelll restriction digest profiles were observed for isolates obtained at various stages of the Pacific Island epidemics, suggesting that extensive sequence evolution did not accompany Ross River virus .spread.

GENETIC ANALYSIS OF KUNJIN VIRUS ISOLATES USING HAEIII AND TAQI RESTRICTION DIGESTS OF SINGLE‐STRANDED cDNA TO VIRION RNA

“…Some of these genetic types show stable geographical associations. Faragher et al (1985b) estimated that 1 -5-5070 sequence divergence exists between genetic types of RRV. If our data are subjected to the same mathematical analysis (Nei and Li, 1979), the maximum sequence divergence which exists between any pair of KUN isolates is estimated to be less than 1%.…”

“…Comparison of the Haelll restriction digest profiles of cDNA to infected cell RNA or virion RNA has proved valuable as a guide to the genetic relationships between isolates of Ross River virus, an alphavirus (Faragher, Marshall and Dalgarno, 1985b). In initial attempts to apply this method directly to KUN, total intracellular RNA was extracted from KUN-infected cells and reverse-transcribed using random calf thymus DNA primers and [Q:32p]dCTP.…”

Arboviruses causing human disease in the Australasian zoogeographic region

“…Genomic relationships between 14 field isolates collected from different localities in eastern Australia and various South Pacific islands were investigated by restriction enzyme analysis using Hae III and Taq I restriction enzymes [66]. They fell into three genetic types on the basis of differences between their restriction profiles, with 1.5-5.0% nucleotide sequence divergence between the three types.…”

Geographic distribution and evolution of Sindbis virus in Australia.

“…Molecular epidemiological studies of another Australian alphavirus, Ross River (RR) virus, have shown that distinct genetic types of the virus are associated with geographic origin (Faragher et al, 1985 ;Lindsay et al, 1993 ;Sammels et al, 1995). Thus, this study was undertaken to better understand the genetic variation in alphaviruses and to identify potential mechanisms of spread of these viruses in Australia.…”