A prospective clinical study comparing 74 cases of rotavirus-associated diarrhoea and 100 cases of non-rotavirus-associated diarrhoea revealed a higher incidence of vomiting to be the only significant difference in the former. Bloody stools were seen in about 5-10%, fever in about two-thirds and respiratory symptoms in a quarter of cases regardless of aetiology. The overwhelming majority had mild dehydration of the isonatremic type. Hypokalemia was noted in a quarter of the cases in both groups.
Keywords: General Hospital Kuala Lumpur
A 12-month study was carried out on the molecular epidemiology of rotavirus in urban and suburban Malaysian children. Analysis of faecal samples from 973 hospitalized diarrhoeic children by polyacrylamide gel electrophoresis detected 268 rotaviruses (28%). All isolates were group A rotaviruses, which produced 22 electropherotypes: 16 (91.5%) with long RNA migration patterns and 6 (8.5%) with short patterns. One of the long-pattern electropherotypes was the predominant strain (71.1% of the total electropherotypes) isolated during this study. Although 3 other strains were detected sporadically over the study period, 16 others were present only during the first 7 months and 2 others were confined to the last 5 months. Long- and short-pattern electropherotypes were found to co-circulate extensively. There was a significant association of short-pattern electropherotypes with infection in older children. In addition, the prevalence of vomiting and mean duration of diarrhoea were significantly associated with different electropherotypes.
The distribution of rotavirus G (VP7) serotypes circulating in four locations in Malaysia, representing three geographical areas, was evaluated in 341 RNA-positive stool specimens obtained discontinuously between 1977 and 1988 from infants and young children under the age of five years who were hospitalized with acute gastroenteritis. A total of 306 specimens (256 stool suspensions and 50 that were adapted to growth in tissue culture) that were rotavirus positive by the confirmatory enzyme-linked immunosorbent assay (ELISA) were examined for serotype by ELISA utilizing monoclonal antibodies to rotavirus G serotype 1, 2, 3, 4, or 9. One hundred eighty (59%) of the 306 specimens could be serotyped; of these 180 specimens, 71% were serotype 4, 15% were serotype 1, 4% were serotype 2, and 4% were serotype 3. Serotype 9 rotavirus was not detected. Most (71%) of the specimens tested were obtained in 1988, when serotype 4 predominated in three locations in West Malaysia; no single serotype was predominant in a limited number of specimens from East Malaysia.
The VP4 genetic groups of 151 field strains of human rotaviruses obtained from infants and young children with diarrhea from four locations in Malaysia were analyzed. The strains were adapted to growth in tissue culture and studied further by molecular hybridization of northern blotted RNA to PCR-generated cDNA probes representing amino acids 84-180 of the KU strain VP4, 83-181 of the DS-1 strain VP4, and 83-180 of either the 1076 or K8 strain VP4, representing VP4 genetic groups 1-4 (P1A, P1B, P2, and P3), respectively. The majority (79% of the field strains hybridized with the KU VP4 genetic group 1 probe and were associated with G1, G3, G4, untypable, or mixed G serotypes. VP4 genetic group 1 (P1A) strains were the most common in all locations in Malaysia between 1978-1988. Three strains which exhibited G3 and subgroup I specificity hybridized with the K8 VP4 genetic group 4 probe. These three VP4 genetic group 4 (P3) strains were detected in two different years and locations, extending the initial detection of this VP4 genetic group (the K8 strain) in Japan to a larger geographical area of Asia.
Amongst 107 diarrheal cases studied a bacterial agent was isolated from 71 (66%) cases of which 60 (85%) were due to a single agent and the remaining 11 (15%) were of mixed infections. Enterotoxigenic Escherichia coli (ETEC) was isolated from 65 cases. Other pathogens isolated included Salmonella spp, Shigella spp and rotavirus. There was a higher isolation rate of ETEC from females and rotavirus from males. The infection rate was found to higher for the 0-2 year age group as compared to the 3-5 year age group. Amongst the ETEC isolated the STa 2 toxotype was the predominant type.