Trends in the patterns of IgM and IgG antibodies in febrile persons with suspected dengue in Barbados 2006-2013

OBJECTIVES: To describe the seroprevalence of dengue antibodies in febrile suspected persons and investigated for dengue in this country. DESIGN AND METHODS: This was a retrospective population based study of all febrile children and adults with probable dengue from 2006 to 2013. Persons with probable dengue were investigated for dengue IgM and IgG antibodies in the blood sample drawn between days 3 to 5 of their illness. RESULTS: Among the 8296 cases that were tested for IgM antibodies, 2605 (36.6%) cases tested positive. Of the 7227 suspected cases who were tested for IgG, 5473 (75.7%) were positive. During the study years, between 80% and 90% of persons older than 20 years had a positive IgG antibody. Among the persons younger than five years (excluding the first year), between 10% and 20% had a positive IgM titre and a negative IgG titre, between 5 and10% had a positive IgM and IgG titre, 5% had a positive IgG titre and a negative IgM titre and between 45% and 65% had a negative IgM and a negative IgG titre. Between 37% and 59% had a serological evidence of past dengue in absence of any current dengue. CONCLUSIONS: The pattern of IgG antibodies seen in this study was comparable to those seen in the countries known to be hyperendemic for dengue. Based on the pattern of antibodies, the age of infection was likely to shift down to younger age groups with the likelihood of more severe forms of dengue in the future.

Chlamydia trachomatis antibody and DNA determination in ectopic pregnancy in Trinidad

OBJECTIVE: To determine the prevalence of C. trachomatis in ectopic pregnancy by serum IgG and IgM antibody and by chlamydia DNA in endometrial, Fallopian tube and ovarian tissues. DESIGN AND METHODS: A cross-sectional study included 32 women presenting with tubal ectopic pregnancy and 94 fertile controls. Methods employed were ELISA for IgG and IgM and Polymerase Chain Reaction (PCR) and in situ hybridization (ISH) for DNA. RESULTS: Chlamydial IgG and IgM antibody detection was higher in the ectopic than the control groups (IgG, p<0.01; IgM, p<0.01). A similar finding was also noted for chlamydia DNA by PCR (p<0.05). DNA detection was also significantly higher at each site in the upper genital tract (endometrium p<0.01, Fallopian tube p<0.05, ovary p<0.05). CONCLUSION: By antibody detection, this study confirms the role played by genital tract C. trachoma infection and subsequently ectopic pregnancy, but more importantly, identifies chlamydial DNA in upper genital tract tissues. These results support allocation of resources towards screening programmes for C. trachomatis.(Au)

Estimating the time of HTLV-I infection following mother-to-child transmission in a breast-feeding population in Jamaica

Mother-to-child transmission of human T-cell lymphotrophic virus type 1 (HTLV-I) is primarily due to prolonged breast-feeding (>6 months) in the post-natal period. Most infant infections are not identifiable until 12-18 months of age by available whole virus Western blot serologic tests because of their inability to distinguish passively transferred maternal antibody from infant antibody. We investigated two methods to assess more accurately the time of infant infection. In prospectively collected serial biospecimens, HTLV-I-specific immunoglobulin (Ig) isotypes of IgM and IgA were determined by Western blot and HTLV-I proviral DNA was detected by polymerase chain reaction (PCR). IgA and IgG reactivity was assessed in periodic serum samples from 16 HTLV-I-seropositive children while IgM reactivity was observed in 100 percent of children at 24 months of age and 73 percent of children at 6-12 months of age; however, this could represent maternal and not infant antibody. Both IgA and IgM reactivity were insensitive indicators of infection, with only 50 percent of children showing reactivity at 24 months of age. PCR testing was performed in biospecimens obtained from 11 of these children. An estimated median time of infection of 11.9 months was determined by PCR, which was similar to the median time to infection determined by whole virus Western blot (12.4 months; P=0.72). PCR Tests support a median time to infection that is similar to that estimated by whole virus Western blot. (AU)

Assessment of the efficacy of an IgM-elisa and microscopic agglutination test (MAT) in the diagnosis of acute leptospirosis

In a prospective study in Barbados between 1979 and 1989, 321 cases were diagnosed in 638 patients presenting at a hospital with symptoms of leptospirosis. Initial diagnosis was based on patient history and characteristic signs and symptoms. In 92 cases (29 percent), diagnosis was confirmed by isolation of organisms from the blood, urine, or dialysate fluid; in the remaining 229 cases (71 percent) diagnosis was confirmed by serology alone. Results of an IgM-ELISA and microscopic agglutination test (MAT) in cases with isolates and in non-specificity of the tests. The sensitivity of IgM detection by ELISA was 52 percent in the first acute-phase specimen, increasing to 89 percent and 93 percent in the second acute-phase specimen, increasing specimens respectively. The specificity of the IgM-ELISA was high (> or =94 percent) in all specimens. The sensitivity of the MAT was low (30 percent) in the first acute-phase specimen, increasing to 63 percent in the second acute-phase specimen and 76 percent in the convalescent specimen. The specificity of the MAT was > or = 97 percent in all specimens. (AU)

Evaluation of the MRL diagnostics dengue fever virus IgM capture ELISA and the PanBio Rapid Immunochromatographic Test for diagnosis of dengue fever in Jamaica

We evaluated two new commercial dengue diagnostic tests, the MRL Diagnostics Dengue Fever Virus IgM Capture ELISA and the PanBio Rapid Immunochromatographic Test, on serum samples collected during a dengue epidemic in Jamaica. The MRL ELISA method correctly identified 96 percent (78 of 80) of the samples as dengue positive, while the PanBio test identified 100 percent (80 of 80). Both tests were 100 percent (20 samples of 20) specific.(Au)

The Guillain-Barre syndrome following dengue fever

A 44 year old female presented with fever, muscle aches, rash and a low platelet count. IgM antibody to dengue virus was positive. Two weeks later she developed a flaccid areflexic quadriparesis. Nerve conduction studies showed a predominantly demyelitinating sensory motor polyneuropathy consistent with Guillain-Barre syndrome. Despite the relatively common occurence of dengue fever, an associated polyradiculoneuropathy is distinctly uncommon.(AU)

Features of toxoplasmosis in the Caribbean - abstract

In 1995 and 1996, 7.5 percent of 321 serum samples (IgM) and 48.0 percent of 352 serujm samples (IgG) assayed for antibiotics at CAREC, were positive for exposure to Toxoplasma. IgM antibodies were not detected in the first 6 months of life, but thereafter levels rose to peak (27.3 percent) in the >6 month - 10 year age group. IgG rose from 16.7 percent in the youngest to 62 percent in the adult age group. Symptoms most commonly associated with positive IgMs were lymphadenopathy (20.8 percent) > eye disease (11.8 percent) > congenital events (7.7 percent). IgG antibodies were associated with eye diseases (53.5 percent) > congenital manifestation (50.0 percent) > missed abortions(41.0 percent) >lymphadenopathy (36.0 percent) > perinatal events (27.8 percent) > central nervous systems symptoms (21.1 percent). IgM determinants were more commonly obtained in sera from Suriname (7.7 percent) > Barbados (7.4 percent) > St. Lucia (4.2 percent). For IgGs the order was Grenada (66.7 percent) > St Lucia (61.1 percent) > St. Vincent (50.0 percent) > Barbados (47.8 percent) >Suriname (46.2 percent). (AU)

Viral specific humoral immune responses following transfusion-related transmission of human T cell lymphotropic virus type-I infection

The immunoglobulin (Ig) isotypes of antibodies to specific proteins of the human T cell lymphotropic virus type I (HTLV-I) were determined by Western blot analysis of serial specimens from six individuals who experienced HTLV-I seroconversion following blood transfusion; five remained asymptomatic carriers, while one developed HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) 32 weeks posttransfusion. Analysis of Ig isotypes demonstrated that while IgM was the most frequent early response to gag (p19, p24) and env (r21e) proteins within the first 3 months following transfusion, IgG and IgA responses could also be detected within this period. HTLV-I-specific antibody responses plateaued in all Ig isotypes, including IgM, wtihin the next 4- to 6-months period following transfusion and pesisted through the entire study period (> 4 years). Comparison of antibody profiles in Ig isotypes and IgG1 and IgG3 subclass among asymptomatic carriers and one individual who developed HAM/TSP demonstrated no evidence of isotypic prominence or IgG subclass restriction in either group. These results indicate the appearance of HTLV-I-specific IgM that persists even after the primary infection and suggest that such responses does not appear to provide an early marker of seroconversion. Further, we found no evidence of isotypic prominence or restriction of the antibody response in recipients who remained asymptomatic compared to one who developed HAM/TS.(AU)

Evaluation of methods for the laboratory diagnosis of malaria in Guyana

When 297 blood samples taken from patients attending a fever clinic in Georgetowm Public Hospital were examined microscopically, after thick and thin blood films had been stained with Giemsa, one hundred and forty-two (47.8 percent) were microscopically positive for malaria. After processing the patients' serum samples by the Indirect Fluourescent Antibody (IFA) technique, specific IgG and IgM antibodies were detected in 239 (81.3 percent) and 179 (60.1 percent), respectively, of the sera. Based on the microscopical findings, the IFAT gave positive and negative values of 54.4 percent and 81.8 percent (IgG), and 57.5 percent and 67.8 percent (IgM), suggesting that the IgM would be more useful than the IgG in the diagnosis of current malaria. An odds ratio analysis showed that the presence of symptoms, IgG or IgM antibodies, as well as visits to endemic regions, could be good indicators of current malaria. Age and occupation are not. The microscopical method will continue to be the gold standard - the best available criterion for the validation of our tests - for our diagnosis of acute malaria. (AU)

Dengue activity in Puerto Rico

The laboratory-based dengue surveillance program in Puerto Rico aims to provide early and precise information to public health officials on four aspects of increased dengue activity: time, location, virus stereotype, and disease severity. The Dengue Branch, San Juan Laboratories (SJL) of the National Center for Infectious Diseases, Centers for Disease Control, receives blood specimens from government clinics, public and private hospitals, and physicians' offices throughout Puerto Rico. These specimens are sent directly or collected locally and transported to SJL by personnel of the Community Hygiene Division (HAFI, for its initials in Spanish) of the Puerto Rico Health Department (PRHD). All serum specimens are tested for anti-dengue IgM to a mixture of four dengue virus antigens, by IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA). All specimens that test positive by MAC-ELISA are further evaluated with an IgG-ELISA to determine whether the infection is primary or secondary. Up to 125 early acute-phase samples per week are processed in C636 mosquito cell cultures for attempted virus isolation. In addition, sera from all patients with haemorrhagic manifestations and all patients from outside Puerto Rico and the U.S. Virgin Islands, if collected fewer than 6 days after onset of illness, are injected into Toxorhynchites mosquitoes. Dengue virus-infected cell cultures or tissues from inoculated mosquitoes (AU)

Immunological profiles in patients with chronic glomerulonephritis - abstract

The objectives of the study were to determine the humoral and cellular immunological profiles of 14 patients with chronic glomerulonephritis (CGN) who were about to be dialyzed. Fourteen healthy subjects matched for age, sex and ethnic origin served as controls. Serum IgG levels showed no significant difference in the two groups. However, serum IgA levels were elevated (p<0.01) but serum IgM levels were suppressed (p<0.001). Immune complexes (IC) were prepared by the polyethylene glycol 6,000 precipitation method and their immunoglobulin content measured. The IgG and IgM levels in IC were markedly depressed (p<0.001, p<0.001 respectively. IgG subclass determinations showed that IgG1 and IgG3 were essentially the same in patients and controls. The IgG2 level, however, was markedly elevated (p<0.02) in patients. Cellular immune responses to the rheumatogenic M41 and to the nephritogenic M55 cell membrane antigens at 3 concentrations (100, 10, 1 ug/ml) as well as to phytohaemagglutinin (PHA) a non-specific mitogen, were measured. In patients, there was depressed cellular sensitivity to the M55 antigen at all 3 concentrations (p<0.01; p§.05; p<0.05, respectively). This suppression was greatly exaggerated when cellular sensitivity to the M55 antigen at the same 3 concentrations was measured (p<0.001, p<0.001, p<0.001 respectively. Patients and controls showed no difference in their response to PHA. These results suggest that both the cellular and humoral immunological factors play a role in the pathogenesis of chronic renal disease (AU)

A serological survey for leptospiral agglutinins among patients in a Barbadian general practice - abstract

Sera from 1,419 patients who attended a Barbadian general practice for a variety of complaints between 1st April and 30th April 1988 were examined for leptospiral agglutinins by the microscopic agglutination test. Sera from patients presenting with pyrexia of unknown origin, jaundice or kidney complaints, and from those whose titre was > 1:400, were also examined by the ELISA for IgM and IgG antibodies. Only one patient was diagnosed clinically as possibly having mild leptospirosis, but three others had been recently infected and some mild cases may have been missed. Altogether, 177 of the patients (12.5 percent) were positive at titres> 1:50. These were 104 of the 739 males (14 percent) and 73 of the 680 females (11 percent) (no statistically significant difference). Seropositivity tended to increase with age (p<0.01), and the highest rates were in agricultural workers (35 percent), labourers (24 percent) and non-manual outdoor workers (19 percent). The difference in seropositivity between the various indoor and outdoor occupational groups was highly significant (p<0.005). Autumnalis (31 percent of the sero postives), Panama (15 percent), Australia (14 percent) and Pyrogenes (11 percent) were the serogroups most commonly recorded among the seropositive patients. Autumnalis predominated in each of the main occupational groups except indoor non-manual workers where Panama, Pyrogenes and Australis occurred more frequently. Ninety-five per cent of the positive titres ranged between 1:50 and 1:400. Titres tended to increase with age, but there was no obvious association between higher titres and particular occupations (AU)

Immunoglobulin and C3 levels in maternal and cord blood in Jamaica

IgG, IgM, IgA and C3 were estimated by radial immunodiffusion (RID) in one hundred paired maternal and cord blood samples. The mean maternal IgG, and IgM, and IgA were 2112 mg/dl, 118 mg/dl and 251 mg/dl, respectively, while in corresponding infants, the mean levels were 2194 mg/dl, 36 mg/dl and 19 mg/dl. Mean cord serum C3 levels was 113 mg/dl, approximately half the maternal level (203 mg/dl). Variation in the gestational age, birth weight, duration of labour and maternal pre-eclamptic toxaemia did not significantly affect the immunoglobulin levels. Seven out of 36 (16 percent) cord blood with IgM level greater than 36 mg/dl showed either fourfold rise or high antibody titres against one of the TORCH (toxoplasma, rubella, cytomegalovirus and herpes simplex virus) agents. Screening of cord serum for IgM levels can be of particular value in detection of newborn infants with clinically apparent or inapparent intrauterine infections (AU)

Immunoglobulin and C3 levels in normal human amniotic fluid

Forty-one amniotic fluid samples were tested by single radial immunodiffusion, using Hyland plates for the demonstration of IgG, IgA, IgD, IgM and C3. All of the immunoglobulins except IgM could be detected throughout gestation. There was a tendency to increase during mid-pregnancy and thereafter to decrease toward term. IgM was detected in only 5 samples (12.2 percent) obtained at term. The literature is reviewed with particular emphasis on IgD, IgM and C3 in amniotic fluid (AU)

Serum immunoglobulin levels in children with homozygous sickle cell disease

Serum immunoglobulin levels (IgA, IgG, and IgM) have been assayed in a representative sample of children (aged 1-7 years) with homozygous sickle cell disease and in age/sex-matched control children with a normal haemoglobin genotype, followed from birth in a prospective cohort study. In SS disease, significant elevation of IgA occurred from the age of two years and of IgG from the age of six years. IgM levels were not significantly different in the two genotypes. The mechanisms contributing to these changes in immunoglobulins are currently unclear as is their clinical significance.(AU)

The development and use of an antibody capture radioimmunoassay for specific IgM to a human parvovirus-like agent

An IgM-antibody capture radioimmunoassay (MACRIA) was developed for detection of IgM antibody specific for the human parvovirus-like agent B19. Diagnosis of infection with this agent by either antigen detection or antibody seroconversion had been made by counter-current immunoelectrophoresis (CIE) in 18 cases of aplastic crisis occurring in children with homozygous sickle-cell desease. The MACRIA described here gave positive results in 17 of 18 cases; in the remaining case only an acute specimen taken from the patient during viraemia and late convalescent specimens taken 184 and 247 days after onset of illness were avaliable. The test was used to investigate 20 further cases of aplastic crisis in which neither viral antigen nor antibody seroconversion could be detected by CIE. Detection of virus-specific IgM permitted diagnosis of infection with this parvovirus-like agent in 17 of these cases. In the remaining three cases only single serum specimens taken late in convalescence, 82, days or more after the onset of symptoms, were available. In addition to these 34 cases of aplastic crisis in which primary infection with this agent was diagnosed by MACRIA, seven cases of apparent 'silent' infection detected by CIE were investigated. The test permitted the discrimination between primary infection and re-exposure to the virus in six of these patients. The use of this assay has added a considerable weight of evidence implicating primary infection with this parvovirus-like agent as an important cause of aplasic crisis in children with sickle-cell disease. Furthermore, MACRIA permits diagnosis of infection when only single serum specimens taken up to ten weeks after infection are available. Thus the use of this test will significantly facilitate the investigation of other clinical syndromes of presumptive infective infectious aetiology (AU)

Infantile cortical hyperostosis with raised immumoglobulins

Two cases of infantile cortical hyperostosis are reported. Both had raised immunoglobulins. Particularly remarkable were the IgA and IgM levels, a finding infrequently reported (AU)

Immunological studies in Schistosoma mansoni infection in St. Lucia

An investigation was made of the immunological status of matched groups of patients with Schictosoma mansoni infection in St. Lucia, one group with hepatosplenic disease and the other with only intestinal disease. No impairment of humoral or cellular immunity was detected in either group. IgG and IgM levels were above normal range and were higher in the patients with intestinal disease, but only the difference between groups in IgG level was statistically significant. In their reaction to specific schistisome antigens and ability to develop delayed hypersensitivity, the groups were about equal. (AU)