A consecutive series of 24 patients with clinical features of primary dengue infection and 22 controls (14 patients with viral fever of unknown origin and 8 healthy subjects) were assayed for serum levels of tumour necrosis factor (TNF). The acute sera of the 24 patients with clinical dengue infection were positive for dengue virus-specific IgM antibody. Clinically, 8 had dengue fever (DF), 14 dengue haemorrhagic fever (DHF) and 2 dengue shock syndrome (DSS). All 16 patients with DHF/DSS had significantly elevated serum TNF levels but the 8 DF patients had TNF levels equivalent to that in the 22 controls. A case is made for augmented TNF production having a role for the pathophysiological changes observed in DHF/DSS and mediator modulation as a possible therapeutic approach to treatment.
Partially purified DEN3 virus was used as antigen in a sensitive dot enzyme immunoassay (DEIA) for the detection of antibodies to flavivirus antigens. We describe here the method used to prepare and optimise the antigen-bearing nitrocellulose membranes and present the results obtained from screening 20 acute phase sera from patients shown to have had recent dengue infections by the haemagglutination inhibition (HI) test. Sixteen pairs of acute and convalescent sera from dengue-negative patients had no detectable antibody to dengue virus by HI. These were shown to have no antibody detectable by DEIA. Sera positive for dengue antibodies by HI had DEIA titers ranging from 10 to several thousand times greater than the titers detected by HI.
Paired sera from 101 Malaysian children aged up to 10 years and suffering from respiratory illnesses were examined serologically for evidence of respiratory viral infections. Of these children, 32.6% showed rising antibody titres for one or more of the test agents. Respiratory syncytial virus appeared to be the main respiratory pathogen involved, followed by Mycoplasma pneumoniae, parainfluenza viruses, adenoviruses, and influenza A virus. These findings are generally similar to those reported by others in temperate and tropical countries.
Serum specimens were collected from 6 species of animals living in 9 states of Malaysia including Sabah, North Borneo in 1993. Antibodies against Japanese encephalitis (JE) virus in these sera were detected by means of hemagglutination-inhibition (HI) and neutralization (NT) tests. By HI test, 702 of 2,152 (32.6%) sera showed positive results. Higher positive rates were obtained by the NT test, in which 1,787 of 1,927 (92.7%) sera had antibodies against JE virus. All serum specimens with positive HI were confirmed as positive by the NT. Swine sera showed especially higher rates of antibody positive and higher antibody titers compared with other animals. These results suggest that JE infections are widely distributed among many animals of Malaysia, and pig is the most susceptible amplifier host for JE virus.
In 1990 the Institute for Medical Research carried out a serosurvey in the state of Kelantan to study the age stratified immune prevalence rates for measles and poliomyelitis. Our findings indicate that 981 out of 1,097 (89%) of the population screened had measles antibodies and more than 90% (366 out of 400) had antibodies to all three serotypes of poliovirus. The susceptible group for measles was infants below one year of age, of whom 53.3% (8/15) did not have measles antibody. Of 400 subjects, 125 (31.3%) who were either incompletely vaccinated or had not been vaccinated against poliomyelitis, had polio neutralizing antibodies to all three poliovirus serotypes, suggesting herd immunity in the population. No high risk age group could be identified for poliomyelitis.
An experimental oil emulsion Newcastle disease vaccine was evaluated for its efficacy in broiler chickens. A group of chickens vaccinated at one day old with a live lentogenic Newcastle disease vaccine and subsequently revaccinated at three and eight weeks old with the experimental oil emulsion vaccine showed satisfactory haemagglutination inhibition antibody response which persisted for 18 weeks. Between 90 and 100 per cent of the vaccinated chickens were protected when challenged with the velogenic viscerotropic Newcastle disease virus. Although the vaccinated chickens were protected against clinical disease, virus could be isolated from a number of birds. By day 10 to 12 after challenge all the chickens were free from Newcastle disease infection.
An epizootic of measles occurred in a group of 31 silvered leaf-monkeys (Presbytis cristatus) that had been in captivity for 4-12 months. Twenty-four of the monkeys exhibited a maculopapular rash that persisted for 6-9 days. A serous to mucopurulent nasal discharge and conjunctivitis were seen in some animals. Eight monkeys died during the epizootic; however, their deaths could not be directly attributed to measles. Serum samples from the surviving monkeys collected 1-2 months prior to, and 5 weeks after, the epizootic were examined by the complement-fixation and hemagglutination-inhibition tests for antibodies to measles virus. The preepizootic complement-fixation titers were all less than 1:4 and hemagglutination-inhibition titers, less than 1:10. The postepizootic complement-fixation titers in 21 of 23 surviving monkeys ranged from 1:8 to 1:128, and hemagglutination-inhibition titers in 22 of 23 monkeys ranged from 1:40 to 1:80 or greater.
An investigation of an outbreak of acute conjunctivitis in Kuala Lumpur from May to August 1978 was made. A total of 2,133 cases was involved, most of whom were adult Malay males of low income status from the surrounding villages and low-cost flats. The majority of cases had bilateral conjunctivitis with clear discharge. Pain and subconjunctival haemorrhage were not common and recovery, mostly without complications, occurred within 1 week. Eye scrapings and paired sera specimens were examined and the causal agent was found to be Coxsackievirus A24 (CA24).
A study was carried out at the University Hospital, Kuala Lumpur, Malaysia to determine the age-specific prevalence of measles infection by serology and the age specific - seroconversion rates following measles vaccination. The results show that the percentage of children with passively acquired measles antibodies decreased with increasing age fill three to five months of age. From 12 months of age, the percentage of positivity increased sharply due probably to natural infection. The geometric mean antibody titre was low at birth, but from six months it started to increase. These results indicate that measles infection is common in Malaysia and a small number of children began to acquire natural measles infection from six to eight months of age; however the peak age for the acquisition of measles infection was from 12 months to five years of age. Seroconversion rates following vaccination from nine months of age, ranged from 94-99%. However, the rates and the geometric mean titre were higher among those vaccinated at 11 months of age or older compared with those vaccinated at nine or ten months of age. Based on the above results, it is concluded that the optimum age for measles immunization in Malaysia should be 11 months.
One-day-old chickens were transported from Australia to Malaysia and vaccinated orotracheally with an uninactivated vaccine prepared from avirulent Australian V4 strain of Newcastle disease virus (NDV). The vaccination regimes were as follows: group A, once, at 2 weeks old; group B, once, at 3 weeks old; group C, twice, at 2 and at 3 weeks old; group D, direct contact with groups A, B, and C; and group E, indirect contact with groups A, B, C, and D. Group F was unvaccinated controls. Challenge was with NDV virulent Ipoh AF 2240-226 strain, administered at 4 weeks old intramuscularly to 10 chickens in each group and orotracheally to 10 chickens in each group. The remaining chickens were challenged by contact with the inoculated chickens. Group mortalities following challenge were: A, 1/77; B, 1/34; C, 0/39; D, 0/45; E, 6/43; and F, 60/60.
Precipitating antibodies to an insect pathogenic RNA virus of Darna trima from East Malaysia have been found in a small percentage of human sera from several different groups of persons in West Malaysia and the United Kingdom. No associated illness was identified. The results suggest that an antigenically related virus or viruses are present in the environment that may be associated with symptomless or inapparent infections in man.
A study of Kuala Lumpur blood donors for HBsAG, anti-HBc and DNA polymeraes showed that 5.5% in the sample population was positive for HBsAG, 50.1% for anti-HBc and 10.1% for DNA polymerase activity. There was no significant difference of the HBsAG among the Malay, Chinese and Indian groups. However, a significant difference was observed for the anti-HBc and DNA polymerase activity between the Indian and the Malay/Chinese groups. Both analysis were significantly lower in the Indians but there was no significant difference between the Chinese and the Malays.
A serological study on dengue infection conducted in Singapore during the period 1982 to 1984 showed that 54.4% of the healthy population between 6 months and over 50 years of age surveyed possessed no haemagglutination-inhibition antibody to dengue type 2 virus. Children below 10 years of age showed the lowest antibody prevalence and were at the greatest risk, with 96.6% susceptible to infection, whereas virtually all adults over 40 showed evidence of prior dengue infection. The geometric mean titre showed a rising trend indicating continuing acquisition of infection in the older age groups. The seropositivity rate of dengue infection of males was twice that of females. Among the 3 major ethnic groups, no significant difference in seropositivity was noted between the Malays and Indians, but the differences between Malays and Chinese and between Indians and Chinese were statistically significant. The study confirmed that the successful implementation of the nation-wide Aedes control programme is reducing endemic dengue virus transmission in the country.
During 1984-1985, a total of 838 sera obtained from individuals of different age groups, mostly blood donors and those whose sera were received for VDRL tests and other serological investigations. The sera were titrated for complement fixing antibodies against cytomegalovirus (Ad169 strain). Three hundred and fifty two (41%) out of 838 sera showed significant antibody titre. The incidence of this virus infection varied form 26% in the age group of 11-20 years to 59% of those above 50 years of age. Geometric mean titre (GMT) was highest (22) in age groups of 11-20 years and those over 50 years indicating active viral infection in these two age groups. GMT was also significantly higher in females in all age groups except in the age group of 21-30 years and those above 50 years, indicating that active viral infection is more common in females.
Sera obtained from 3,472 persons in Malaysia, Thailand, Philippines and Indonesia were tested for the presence of antibody to adult T-cell leukemia-associated antigen by the gelatin particle agglutination test and indirect immunofluorescence. Among these, only two seropositives were identified. One was a 30-year-old male Malaysian of Indian origin. The other was a 42-year-old female Thai who resided in Bangkok. These results suggested that the infection of human T-lymphotropic virus type 1 might not be endemic in these countries.
A modification of the IgM-capture ELISA which can provide an early diagnosis for dengue infection is presented. The test is technically simple compared to HI and appears to be more sensitive. It has the advantage over HIT for the detection of specific IgM in that it is more sensitive and the reading of the result is not subjective. There is the possibility of the test being able to replace HI and HIT in the future.
A case of Newcastle disease virus infection in a female laboratory technician is reported for the first time in Malaysia. Infection was acquired by droplet infection of the eye while grinding infected chicken in the laboratory. The case was confirmed by isolation of Newcastle disease virus from an eye swab taken from the subject on the first day of clinical signs. A four-fold rise of haemagglutination-inhibition titre was shown when sera on the third day of infection and 15 days later were compared.