The indirect hemagglutination (IHA) test done with turkey red cells was applied to 173 serum samples obtained from patients and persons exposed to Wuchereria bancrofti and Brugia malayi in endemic areas of Peninsular Malaysia. A crude extract of adult worms of the rat filaria, Breinlia booliati, was used as the antigen. When a titer of 1:16 was taken as negative, positive IHA test rates in sera from microfilaria-negative persons in endemic areas, microfilaremic cases, and patients with clinical filariasis were 13%, 75%, and 80%, respectively. Results of the IHA test correlated well with results obtained with the indirect fluorescent technique.
The screening for anti-amoebic antibody among a group of donors was to obtain negative control serum samples for an on-going antigen development assay in diagnosis of amoebic liver abscess. Out of 200 samples, 125 (62.5%) were negative, whereas 44 (21.5%) had IHA titer of less than 1:128 and 31 (16.0%) of the samples had significant IHA titers of 1:128 or more, in which 2 serum samples gave titers of 1:4096.
Toxoplasmosis is a worldwide zoonosis caused by the protozoa Toxoplasma gondii which affects human and animals. Village chickens (Gallus domesticus) most commonly known as Ayam Kampung or free-range chickens, have been suggested to play a role in the epidemiology of toxoplasmosis. This study determines the presence of T. gondii in the village chicken populations in two states of Malaysia. A total of 50 serum samples from the chickens from Selangor (n=20) and Melaka (n=30) were collected and analysed using commercial serological kits. T. gondii antigen was detected in 20% (Selangor 30%; Melaka 13%) samples using ELISA test and anti-T. gondii antibody was detected in all positive ELISA samples using the indirect haemagglutination test (IHAT). Histopathological examination revealed tissue changes such as inflammation and degeneration in brain and liver of seropositive chickens. This is the first report of T. gondii infection in the village chickens in Malaysia.
A combined enzyme immunoassay (micro-ELISA) technique was established for measuring autoantibodies against thyroglobulin and thyroid microsome, involving the immuno-dot blot technique. Thyroglobulin and thyroid microsome antigens (1 g/L each) prepared from normal thyroids were spotted separately onto nitrocellulose membrane filter discs. Results by this method and those by immunofluorescence correlated well. The percentages of confirmed positives were 30% and 48% and the negatives were 58% and 46% (n = 50) for thyroglobulin and microsome, respectively. Testing these samples by gelatin agglutination gave a high percentage of false positives (up to 20%, n = 128) and hemagglutination testing yielded a high percentage of false negatives (up to 20%, n = 45). The titer of autoantibodies by the micro-ELISA technique was greater than by agglutination. This technique is highly specific and sensitive.
Interpretation of the indirect hemagglutination test (IHA) for melioidosis in endemic areas is difficult because of the presence of antibodies in apparently healthy individuals. Fifty-three out of 200 healthy blood donors in Malaysia showed positive antibody titers (> or = 1 : 40) against Burkholderia pseudomallei. Seven percent had an IHA titer of 1 : 40, 11% had an IHA titer of 1 : 80 while 8.5% had a titer > or = 1 : 160. Out of 258 sera sent for melioidosis serology, 7% of the patients had an IHA titer of 1 : 40, 9% had an IHA titer of 1 : 80 while 20% had an IHA titer of > or = 1 : 160. If a titer of > or = 1 : 80 is taken as cut off point for positivity, 29% of the patients had positive melioidosis serology. Increasing the positivity threshold may jeopardize the sensitivity of the test. A more specific and sensitive test is needed.
The relationship between the standard passive mouse protection test or serum antibody titres measured by indirect haemagglutination or enzyme-linked immunosorbent assays and active protection in buffaloes immunized with different types of haemorrhagic septicaemia bacterins was investigated. Groups of 2-3 buffaloes were immunized with the bacterins currently in use in Asia, viz., broth bacterin (BB), alum precipitated vaccine (APV) and oil adjuvant vaccine (OAV) either subcutaneously (BB, APV) or intramuscularly (OAV) and challenged subcutaneously with virulent organisms at different periods post-immunization. Although the passive mouse protection and indirect haemagglutination tests carried out with the pre-challenge sera from vaccinated buffaloes revealed no relationship with active protection in buffaloes, a relationship was observed between the ELISA antibody titres and protection. In contrast, a dose-response relationship was observed between the homologous active and passive mouse protection test.
Current diagnosis of melioidosis is based on bacterial culture and/or serology which is becoming increasingly useful. An IgM-ELISA using heat-killed whole cells of Pseudomonas pseudomallei was developed and compared with an indirect haemagglutination technique (IHAT) and an indirect immunofluorescent technique(IFAT). The IgM-ELISA using a P:N ratio of > or = 2 had a sensitivity of 91% and a specificity of 96%. All 3 assays were further used in a seroepidemiological survey amongst different groups of patients and healthy individuals. It was found that the IFAT performed better than the IHAT, detecting antibodies to P. pseudomallei in 6% of diabetics, 5% of pyrexics, 8% of pregnant women and 3% of farmers. For the same groups the IgM-ELISA detected antibodies in 1% of pyrexics, 8% of pregnant women and a further 14% of farmers. The IgM-ELISA was found to be sensitive and useful for the serological diagnosis of acute melioidosis.
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.
This article describes a case of leptospirosis in a man who returned from caving in Sarawak, Malaysia, and includes a discussion of epidemiology, pathophysiology, diagnosis, prevention, and treatment. The patient presented with symptoms of leptospirosis, which was confirmed by microhemagglutination titers. He became infected despite taking doxycycline daily for malaria prophylaxis. Leptospirosis is an important consideration in any returned traveler with fever. The spirochete spreads from animals to humans via water. Caving in tropical endemic zones may increase exposure risk due to the combination of multiple skin abrasions with immersions. Water in caves may increase infection risk because of increased water pH. Standard prophylaxis may be inadequate in cases of high-risk exposures.
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.
The indirect hemagglutination test was used to measure malaria antibody levels in residents of an endemic area of Malaysia. Blood specimens were collected at 4-week intervals for a year. Seropositivity rates increased with age and number of episodes of malaria in young children. Although antibody levels were variable, titers tended to rise with parasitemia and fall in the absence of detected parasites. In general, the serologic indices tended to reflect the parasitologic findings.
A cohort of 62 persons living in a malaria-endemic area was examined by serology and by blood film 14 times over a 56-week period. Serologic responses (indirect hemagglutination test) of the group as a whole reflected the malaria transmission as determined by blood slide examination. The serologic responses of individuals showed titer changes that were not always consistent with blood slide results. The use of chloroquine may have modified the host's immune response.
Epidemiological studies of human leptospirosis have generally been limited to countries with specialized laboratories employing the microscopic-agglutination (MA) test. The sensitized-erythrocyte-lysis (SEL) test is much simpler for routine hospital laboratories to carry out and it has been found valuable in the diagnosis of human leptospirosis. This paper reports the results of studies of the SEL test as an epidemiological tool in serological surveys.The results showed that the significant SEL titre was 1:80 and that the sensitivity of the test depended possibly on the antigen preparation and the amount of complement used. Most of the SEL antibodies were found to persist at significant titres for about 1 year after active infection, but less than half persisted longer than that. The SEL test is therefore useful for detecting recent infections and for indicating that stability of leptospirosis in an area.The endemicity of leptospirosis in West Malaysia was confirmed by the SEL test, based on the employment of 1:80 as the significant titre.