Serological evidence of hantavirus infections in Malaysia.

Hantaviruses are primarily rodent-borne and transmission is by inhalation of virus-contaminated aerosols of rodent excreta, especially urine and saliva. The genus Hantavirus, family Bunyaviridae, comprises at least 14 serotypes and the symptoms of clinical illness range from mild fever to severe hemorrhagic manifestations with renal complications. Many countries in Southeast Asia are unaware of the importance of hantavirus infections and give them low priority. Malaysia, like other countries in the region, has conducted very few studies on the epidemiology of hantaviruses - and even these were conducted in the 1980s. Using a more extensive range of hantavirus antigens, we conducted a seroprevalence study of rodents and humans and found further evidence of hantavirus infections. Moreover, the data from the antibody profiles strongly suggest the presence of different hantaviruses at the study sites.

Chikungunya infection--an emerging disease in Malaysia.

Many countries neighboring Malaysia have reported human infections by chikungunya virus, a mosquito-borne togavirus belonging to the genus Alphavirus. However, although there is serological evidence of its presence in Malaysia, chikungunya virus has not been known to be associated with clinical illness in the country. An outbreak of chikungunya virus occurred in Klang, Malaysia, between December 1998 and February 1999. The majority of the cases were in adults and the clinical presentation was similar to classical chikungunya infections. Malaysia is heavily dependent on migrant workers from countries where chikungunya is endemic. It is speculated that the virus has been re-introduced into the country through the movement of these workers.

Evaluation of WHO monoclonal antibody kit for diagnosis of acute respiratory viral infections.

In 1990 and 1991, six laboratories located in the WHO Western Pacific Region (WPR) and South East Asian Region (SEAR) were selected, based on their experience in the immunofluorescence antibody technique (IFAT), to participate in the evaluation of a WHO monoclonal antibody (Mab) kit to detect respiratory syncytial (RS) virus, influenza A virus, influenza B virus, parainfluenza virus and adenovirus. Despite differences in the initial standardization procedures, the WHO monoclonal antibodies were found to be of high quality, sensitivity and specificity when tested on clinical specimens. The constant supply of affordable high quality reagents from WHO would enable their use in clinical virological laboratories in the developing countries as well as promote the utilization of IFAT as an adjunct to cell culture isolation in the diagnosis of acute respiratory viral infections.

Detection and serotyping of dengue viruses by PCR: a simple, rapid method for the isolation of viral RNA from infected mosquito larvae.

Dengue viruses pose a considerable global public health problem with an estimated 100 million cases of illness every year. This illustrates the need for rapid and reliable diagnostic methods for proper patient management and disease control. Currently, laboratory diagnosis depends on serology or virus isolation, with both methods having certain drawbacks. Alternatively, reverse transcription and polymerase chain reaction (RT-PCR) offers the potential for the rapid, highly sensitive and specific detection of dengue viruses. Since we occasionally encounter the problem of insufficient amounts of patient serum for the direct detection of dengue viruses, a method was developed for the extraction of viral RNA after biological amplification in mosquito larvae. Using this method, 15 of 19 clinical samples tested were correctly identified using RT-PCR.

Fulminant hepatitis in dengue infection.

Eight cases of liver failure and encephalopathy were observed among twenty cases of grade 3 and grade 4 dengue hemorrhagic fever/dengue shock syndrome admitted to the Department of Pediatrics, University Hospital, Kuala Lumpur from January 1990 to December 1991. All patients with deterioriation in mental status showed a marked increase in liver enzymes (aspartate and alanine aminotransaminases) and severe coagulopathy. Six patients needed cerebral protection, including ventilation, intravenous sedation and muscle relaxants. There was one death during the period of study and one case of residual hemiparesis in a boy who had, in addition, intracerebral hemorrhage. All other survivors had complete recovery of liver and neurological function.

Problems in dengue control: a case study.

The control of dengue outbreak requires a multi-pronged effort by the various government agencies. It requires co-operation of the community in the control activities, strict adherence to existing control procedures and guidelines by health personnel, increased manpower where necessary and strengthening co-operation between various health agencies to prevent delay in instituting control measures.

Prevention and management of relapse of peptic ulcer [review, tutorial]

The dictum, "Once an ulcer, always an ulcer" is most likely true, because recent evidence suggests that peptic ulcers do not burn out. In fact, ulcer relapse and with it the potential complications become the major concern in the management of this condition. Prevention and treatment of a disease depends on the understanding of its aetiology. For peptic ulcer, however, therapeutic advances have outpaced scientific attempts to understand its cause. Even though clinicians have been therapeutically successful, there is no clear answer to the fundamental question as to why ulcers in general heal with the known therapeutic agents including H2-receptor antagonists, antacids, proton pump inhibitors, anticholinergics, site-protective agents, and cytoprotective agents. This review examines this question while at the same time outlining the present day understanding of the prevention and treatment of peptic ulcer relapse.

Unusual clinical manifestations of dengue virus infection.

Four recent cases of dengue fever with severe, unusual clinical manifestations are described. Two of these cases had features of fulminant hepatitis and encephalopathy; one of these cases was fatal. The two remaining cases showed hepatitis with renal impairment. The significance and importance of these unusual manifestations of dengue disease are discussed.

Detection of specific IgM in dengue infection.

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.

Optimum age for measles immunization in Malaysia.

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 till 3 to 5 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 6 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 6 to 8 months of age; however the peak age for the acquisition of measles infection was from 12 months to 5 years of age. Seroconversion rates following vaccination from 9 months of age, ranged from 94% to 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 9 or 10 months of age. Basing on the above results, it was concluded that the optimum age for measles immunization in Malaysia should be 11 months.

Enterovirus survey before and after poliomyelitis vaccination in Kuala Lumpur, Malaysia.

Stool samples from healthy children mainly of the low income group aged 0 to 7 years of age from five Maternal and Child Health Centres in Kuala Lumpur were obtained for isolation of enteroviruses. The specimens were collected before and after the mass vaccination given in the face of polio type 1 epidemic which started in October, 1971. The prevelance rate of enteroviruses was 11.9% (3.0% polioviruses, 8.9% non-polio enteroviruses) before the vaccination and essentially the same after. Coxsackie A viruses predominated over the other enteroviruses in the pre- and post-vaccination phases. The highest isolation rate of enteroviruses was observed in children 0 to 2 years age. No significant differences in distribution by sex, race and month were noted. A sharp fall in the prevalence rates of total enteroviruses and polioviruses was noted shortly after the mass vaccination campaign However, the rates reverted to the pre-vaccination state during the next successive years.