Accurate laboratory testing is a critical component of dengue surveillance and control. The objective of this programme was to assess dengue diagnostic proficiency among national-level public health laboratories in the World Health Organization (WHO) Western Pacific Region.
Congenital malaria from Malaysia is reported here for the first time. It occurred in a baby boy born to a 16-year-old primigravida who contracted Plasmodium falciparum infection during pregnancy. She suffered malaria during the later stages of pregnancy and at parturition. The placenta was heavily infested with various asexual stages of P. falciparum. Gametocytes were not seen. Extensive search did not show other species. Cord blood showed very light infection with young trophozoites of P. falciparum. Serological studies using IFA technique showed specific IgG and IgM antibodies to P. falciparum in maternal cord and two early neonatal sera. These serum samples showed lower levels of IgG antibodies against P. vivax and P. malariae, but there were no specific IgM antibodies against these species. The value of specific IgM antibody in the diagnosis of congenital malaria is discussed.
An IgM dot-immunobinding assay (IgM-DIA) was developed for the diagnosis of scrub typhus infection. The whole cell antigens of Karp, Kato and Gilliam strains of Rickettsia tsutsugamushi were immobilized onto nitrocellulose paper and reacted with patients sera. The presence of IgM R. tsutsugamushi specific antibody in the patient sera could be detected by the observation of a visible brown dot on the nitrocellulose paper. The IgM-DIA has a sensitivity of 90.4% and specificity of 81.4% as compared to the indirect immunoperoxidase test. The IgM-DIA is rapid, simple, cost-effective, does not require microscope or incubator. It is recommended as a rapid screening test for the diagnosis of scrub typhus infection in the field or rural area within the hyperendemic region.
A total of 736 sera collected from cord blood babies, children and adults of both sexes and of different age groups in Malaysia were tested using indirect fluorescent antibody technique for Toxoplasma antibodies. The RH strain of Toxoplasma gondii zoites were used as antigen. One hundred and twenty five sera which were reactive at 1:64 or high titres were tested with IgM specific conjugate. Results of the present studies showed that the prevalence of Toxoplasma antibody was highest among the Malays and lowest among children than among adults. The significance of Toxoplasma specific IgM was discussed.
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.
Toxoplasmosis was found not to be an important cause of intrauterine infection in Malaysia as the rate of toxoplasma-specific IgM in 1,060 congenitally defective Malaysian children, 0 to 4 months old (0.4%) was lower than that in 405 normal children of the same age group (2.0%). A total of 8.2 intra-uterine toxoplasmic infections per 1,000 live births was detected of which one-third (2.7 per 1,000 live births) was overt, manifesting symptoms more of liver damage, than eye or brain damage. A comparison was made with the rates in U.S.A. and Europe. The role of toxoplasmosis in abortion needs to be studied.
Serum immunoglobulin G, A, M, D and E levels were determined in the forest-dwelling Orang Asli of age group 8 to 64 years. The levels are higher than observed for urban Malaysians and comparable to levels reported for populations residing in the tropics. There was no significant difference in serum levels of all the immunoglobulins studied in both sexes. The elevated serum immunoglobulins levels are discussed in terms of the nature of the immune defence developed in the Orang Asli to contend with the many parasites prevalent in their environment.
The aim of this study was to determine if knowledge of both the serum HCV RNA and serum anti core IgM antibody status enabled one to predict the histological severity in chronic hepatitis C. We studied 45 female patients with chronic hepatitis C infection. The presence or absence of IgM antibodies to HCV and HCV RNA by PCR in each patient's serum was determined. Liver biopsies performed were scored according to a modified Desmet's histological activity index. Negative HCV RNA patients had least histological change. HCV RNA positive patients who were also IgM antibody positive had lower scores than their IgM negative counterparts. The grade of histological severity is more accurately predictable from knowledge of both the HCV RNA and IgM anti HCV status of the patient.
The IgM-globulin levels were determined for 5,167 cord-sera of apparently normal infants and 281 sera of defective infants aged 4 months and younger. The significant level for IgM-globulin in neonates was found to be 20 mgm/dl (2 SD above mean of the normal) above which the level was regarded as abnormally raised. Significant levels of IgM-globulin were found in 0.2% (11/5, 167) ofnormal neonates and in 40.6% (114/281) of defective infants which is more than 200 times the normal value. Combining the normal and abnormal rates, an overall figure of 23 intrauterine infections per 1,000 live births were obtained for Malaysia. The advantages and disadvantages of the use of serum IgM-globulin elevations for the diagnosis of intrauterine infections were discussed.
110 normal, healthy adults were tested for antibody to hepatitis A (anti-HA) type IgG and 86 (78.2%) were found to be positive. An age-specific prevalence wasfound to be lowest in the lower agegroup and highest in the higher age-group. Out of 24 IgG positive individuals, only one was found to have type IgM. No significant difference in the incidence ofanti-HA type IgG was found between 42 patients in the Urology Unit, General Hospital, Kuala Lumpur and normal individuals (P > 0.1). 15 patients diagnosed as viral hepatitis were investigated for HA V IgG and IgM antibodies. 13 (86.7%) were positive for type IgG. Of this, only five (33%) were positive for the type IgM, suggesting that HA V is the cause of acute viral hepatitis in 33% of cases admitted to hospital as viral hepatitis.
Brucellosis is a zoonotic disease which can be transmitted by direct or indirect contact with infected animal or their products. It is an important public health problem but little is known on brucellosis in the Malaysian population. The aim of this study was to determine the presence of Brucella antibodies using commercial Brucella IgG and IgM ELISA kits (Vircell, SL, Barcelona Spain). A total of 184 sera from suspected patients were received from 16 hospitals in Malaysia over the years 2004 to 2009. Only 10 serum samples (5.4%) were positive for Brucella antibodies in which 5 showed the presence of both IgM and IgG. Most of the positive patients were occupationally involved with animals. This study suggests the seroprevalance of brucellosis among individuals who have contact with infected animals in Malaysia is low.
A commercial Dengue Duo rapid test kit was evaluated for early dengue diagnosis by detection of dengue virus NS1 antigen and immunoglobulin M (IgM)/IgG antibodies. A total of 420 patient serum samples were subjected to real-time reverse transcription-polymerase chain reaction (RT-PCR), in-house IgM capture enzyme-linked immunosorbent assay (ELISA), hemagglutination inhibition assay, and the SD Dengue Duo rapid test. Of the 320 dengue acute and convalescent sera, dengue infection was detected by either serology or RT-PCR in 300 samples (93.75%), as compared with 289 samples (90.31%) in the combined SD Duo NS1/IgM. The NS1 detection rate is inversely proportional, whereas the IgM detection rate is directly proportional to the presence of IgG antibodies. The sensitivity and specificity in diagnosing acute dengue infection in the SD Duo NS1/IgM were 88.65% and 98.75%, respectively. The assay is sensitive and highly specific. Detection of both NS1 and IgM by SD Duo gave comparable detection rate by either serology or RT-PCR.
The objective of this study was to investigate the longevity of positive dot enzyme immunosorbent assay (dot EIA) results for IgM and IgG to a Salmonella typhi outer membrane protein in Malaysian children with enteric fever. The patients were children one month to 12 years of age with clinical evidence of typhoid fever, positive blood or stool cultures for S. typhi, and/or a positive Widal test result who were admitted over a two-year period to General Hospital (Kota Bharu, Malaysia). These patients received standard inpatient treatment for enteric fever including chloramphenicol therapy for 14 days. Dot EIA tests were performed as part of clinical and laboratory assessments on admission, at two weeks, and then at 3, 6, 9, 12, 15, 18, and 21 months postdischarge. Assessment of the longevity of positive dot EIA IgM and IgG titers was done by Kaplan-Meier analysis. In 94 evaluable patients, 28% were dot EIA IgM positive but IgG negative on admission, 50% were both IgM and IgG positive, and 22% were IgM negative and IgG positive. Mean persistence of IgM dot EIA positivity was 2.6 months (95% confidence interval = 2.0-3.1 months) and that of IgG was 5.4 months (4.5-6.3 months). There were no significant differences between the three subgroups. Thus, positive IgM and IgG results determined by dot EIA within four and seven months, respectively, following documented or suspected enteric fever in a child from an endemic area should be interpreted with caution. In other clinical situations, the dot EIA remains a rapid and reliable aid to diagnosis.
Serum samples were obtained within 3 days of capture from 106 cynomolgus monkeys (Macaca fascicularis) in peninsular Malaysia. Fifty-two monkeys were trapped on the fringes of palm oil estates and 54 in dense primary jungle. Sera were tested for antibodies to hepatitis A virus (HAV) with a commercial radioimmunoassay. Twenty-four animals had detectable serum anti-HAV activity (6 of 52 from palm oil estate sites and 18 of 54 from primary jungle sites). Among monkeys at both sites, antibody prevalence was strongly correlated with animal weight: overall only four of 69 monkeys (6%) weighing less than 2.0 kg had serum anti-HAV antibodies, while 14 of 29 (48%) weighing 2.0 to 3.9 kg, and 6 of 8 (75%) weighing 4.0 kg or more, had serum anti-HAV antibodies. These data suggest that wild cynomolgus monkeys in Malaysian jungles become infected with HAV or an HAV-like virus at a rate comparable to that of humans in the same region, and raise the possibility of a sylvatic cycle for HAV.