Rotavirus detection and characterisation in outbreaks of gastroenteritis in aged-care facilities.
BACKGROUND
Although rotavirus is a major cause of gastroenteritis in children, its role in adult gastroenteritis and the sensitivity of different methods for its detection in specimens collected from adults are less well understood.


OBJECTIVE
(1) To examine the frequency and seasonality of rotavirus-associated gastroenteritis outbreaks in aged-care facilities in Victoria, Australia. (2) To determine rotavirus type in these outbreaks. (3) To determine whether other enteropathogenic agents are present in specimens from these outbreaks. (4) To examine the sensitivity of different methods (electron microscopy (EM), reverse transcription-polymerase chain reaction (RT-PCR), enzyme immunoassay (EIA) and latex agglutination (LA)) for the detection of rotavirus in specimens from adults.


METHODS
Specimens from gastroenteritis outbreaks in aged-care facilities forwarded to this laboratory for the years 1997-2000 were tested for enteropathogenic agents by various methods. Epidemiological, clinical and seasonal data from the rotavirus-positive outbreaks were analysed.


RESULTS
Rotavirus was detected by EM in 18 out of 29 individuals associated with seven out of 53 (13%) gastroenteritis outbreaks in aged-care facilities; norovirus was detected in 22 outbreaks (42%) and astrovirus in one outbreak (2%). No mixed viral infection was found in any outbreak. All rotaviruses were typed as Group A by RT-PCR. The rotaviruses in the seven outbreaks were G-typed as follows: G2 (three outbreaks), G4 (two outbreaks), G1 (one outbreak) and G9 (one outbreak). The rotavirus-associated outbreaks were concentrated in mid-winter to mid-spring. The relative sensitivities of the Group A rotavirus detection methods (for the 29 specimens tested) were EM (18), first-round RT-PCR (11), second-round PCR (19), EIA-visual (19), EIA-photometric (19) and LA (13).


CONCLUSIONS
In Victoria, Australia, outbreaks of gastroenteritis associated with rotavirus are quite common in aged-care facilities. They involve Group A rotavirus and have a winter/spring seasonality. G-types G1, G2, G4 and G9 were all detected. EIA, second-round PCR and EM proved sensitive methods for rotavirus detection whereas first-round RT-PCR and LA did not.
Marshall
John
J
Victorian Infectious Diseases Reference Laboratory, 10 Wreckyn Street, North Melbourne, Vic 3051, Australia. john.marshall@mh.org.au
Botes
Jeannie
J
Gorrie
Glenda
G
Boardman
Claire
C
Gregory
Joy
J
Griffith
Julia
J
Hogg
Geoffrey
G
Dimitriadis
Anna
A
Catton
Michael
M
Bishop
Ruth
R
D000368:Aged; D000369:Aged, 80 and over; D004196:Disease Outbreaks; D004797:Enzyme-Linked Immunosorbent Assay; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology; D006707:Homes for the Aged; D006801:Humans; D007124:Immunoenzyme Techniques; D007841:Latex Fixation Tests; D009735:Nursing Homes; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012401:Rotavirus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D012400:Rotavirus Infections / Q000453:epidemiology / Q000821:virology; D012621:Seasons; D012680:Sensitivity and Specificity; D014739:Victoria / Q000453:epidemiology