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PubMed2003

Longitudinal studies in South Indian villages on Japanese encephalitis virus infection in mosquitoes and seroconversion in goats.

Japanese encephalitis (JE) is endemic in Cuddalore district, Tamil Nadu, where Culex tritaeniorhynchus Giles was the major vector. We screened 45 100 adult female Cx. tritaeniorhynchus (902 pools) by enzyme-linked immunosorbent assay and isolated and confirmed JE virus (JEV) by using an insect bioassay system. We had 69 isolates of which 62 (90%) were identified as JEV. The average vector abundance per man hour for Cx. tritaeniorhynchus was 324.5 per month for the period June 1998-May 2000. The average minimum infection rate (MIR) per month in Cx. tritaeniorhynchus was 1.4 (range 0.0-5.6). Every year, a new batch of goats, 20 in the first year and 31 in the second year, born during the non-JE transmission period (January-June), aged <6 months and negative for haemagglutination inhibition (HI) antibodies were procured and placed in the villages as sentinels. Fortnightly, blood specimens were collected from these goats and tested for JE antibodies by HI test. Seroconversions (SCs) were recorded in 14 goats (70%) in the first year and 23 goats (74%) in the second year. JE HI antibody titres in goats were low (1:10-1:80) and these levels declined to undetectable levels in about 4 weeks following SCs. The time sequence of events indicated that four of five peaks of MIR in mosquitoes were followed 1-3 months later by peaks in the proportion of seroconverted goats. We suggest the screening of goats and cattle as a more feasible tool to stratify areas according to JE infection risk to the human population through the regular health system rather than screening mosquitoes using monoclonal antibodies, which is possible only in specialized laboratories.

Animals↗

PubMed1991

[Bilateral Leber's neuroretinitis stellata in Borrelia burgdorferi seroconversion].

We report on a 22-year-old white female with bilateral Leber's stellate neuroretinitis occurring 5 weeks after a viral-like illness. Serological tests revealed a seroconversion for Borrelia burgdorferi indicating an etiological connection. During therapy with 200 mg doxycycline daily for 2 weeks on systemically steroids the optic disc swelling and macular star figure resolved. Visual acuity improved from 0.4 to 1.0 in this time period. It is important that the ophthalmologist should consider Lyme-Borreliosis in isolated neuroretinitis, because the prognosis depends on the time when treatment is initiated.

Adult↗

PubMed1990

[Choriocapillaritis (so-called pigment epitheliitis) in Borrelia burgdorferi seroconversion].

A significant B. burgdorferi seroconversion with an IgM of 1:80 was observed in a patient complaining of loss of vision in his right eye. The finding correlated morphologically with hyperpigmentation and depigmentation in the macular region, similar to pigment epitheliitis or choriocapillaritis. In the course of the following four weeks the IgM decreased by four titer steps. The visual acuity of the patient's right eye recovered from 0.4 on admission to 1.0 on discharge. The angiogram did not reveal any pathology. Since choroidal manifestations have often been documented in patients with B. burgdorferi infections, it is recommended that serological workups be performed in such patients. Studies in larger groups of patients are necessary to establish the relevance of this case report and its significance concerning infection as a cause of choriocapillaritis.

Adult↗

PubMed1988

[Acute primary phase as an indicator of HIV-1 infection. The general symptoms and polymorphic exanthema with mouth mucosal involvement 2 to 6 weeks before seroconversion].

The initial symptoms of an HIV-1 infection were observed in four patients. The following were characteristic for the acute primary phase: (a) initial maculopapular exanthema, especially of the trunk, with occasional transition into a papulovesical appearance; (b) involvement of the oral mucosa, often of aphthous character; and (c) general malaise with fever and lymphadenopathy. The observed cutaneous changes had, on one hand, features of a Coxsackie or mononucleosis exanthema, on the other of secondary syphilis. In three patients seroconversion occurred within 2-6 weeks, the fourth failed to return for follow-up. The listed acute primary symptoms can be used as the earliest indicators of an HIV-1 infection having occurred.

Acquired Immunodeficiency Syndrome↗

PubMed1982

[Seroconversion in juvenile patients and adults after diphtheria immunization].

A total of 155 persons of the Hamburg hospital personnel aged between 15 and 64 years were immunised against diphtheria. Out of 120 prevaccination seronegative persons (including very low diphtheria antitoxin titres) 92 (76.7%) reacted with seroconversion above the diphtheria protection level after the adult dosage of 7.5 IU diphtheria toxoid. Good results were still obtained with a 2.5 IU dosage. The conversion factor of 210 in the age group of 55 to 64 year old persons was sevenfold higher than in the 15 to 24 year old group. Local reactions of the mainly slight nature were seen after vaccination in 20.8%, only immunised person showed a slight increase of temperature. It is recommended to offer reimmunisation with a 7.5 IU dosage before leaving school. Selective immunisation of certain professional groups, such as hospital personnel, should be performed according to age and history, either with 7.5 or 2.5 IU of diphtheria toxoid.

Adolescent↗

PubMed1997

A case-control study of HIV seroconversion in health care workers after percutaneous exposure. Centers for Disease Control and Prevention Needlestick Surveillance Group.

BACKGROUND: The average risk of human immunodeficiency virus (HIV) infection after percutaneous exposure to HIV-infected blood is 0.3 percent, but the factors that influence this risk are not well understood. METHODS: We conducted a case-control study of health care workers with occupational, percutaneous exposure to HIV-infected blood. The case patients were those who became seropositive after exposure to HIV, as reported by national surveillance systems in France, Italy, the United Kingdom, and the United States. The controls were health care workers in a prospective surveillance project who were exposed to HIV but did not seroconvert. RESULTS: Logistic-regression analysis based on 33 case patients and 665 controls showed that significant risk factors for seroconversion were deep injury (odds ratio= 15; 95 percent confidence interval, 6.0 to 41), injury with a device that was visibly contaminated with the source patient's blood (odds ratio= 6.2; 95 percent confidence interval, 2.2 to 21), a procedure involving a needle placed in the source patient's artery or vein (odds ratio=4.3; 95 percent confidence interval, 1.7 to 12), and exposure to a source patient who died of the acquired immunodeficiency syndrome within two months afterward (odds ratio=5.6; 95 percent confidence interval, 2.0 to 16). The case patients were significantly less likely than the controls to have taken zidovudine after the exposure (odds ratio=0.19; 95 percent confidence interval, 0.06 to 0.52). CONCLUSIONS: The risk of HIV infection after percutaneous exposure increases with a larger volume of blood and, probably, a higher titer of HIV in the source patient's blood. Postexposure prophylaxis with zidovudine appears to be protective.

Analysis of Variance↗

PubMed1999

A retrospective study of seroconversion against Toxoplasma gondii during 3,000 pregnancies in Stockholm.

The incidence of Toxoplasma gondii infections in Swedish women during pregnancy is largely unknown. This retrospective pilot study was performed on consecutive sera sampled from 3,094 women at delivery during 1992-93. Specific IgG anti-toxoplasma antibodies were found in 14% (450/3,094). Serum drawn from the women during the first trimester and cord blood from their children were analysed for IgG and IgM anti-toxoplasma antibodies. A seroconversion during pregnancy was found in 4 women, whose children were followed up at 4 years of age. No signs of sequelae, either neurological or ophthalmological, were found in 3 of the children. The fourth child died at 1 year of age of a disease of different aetiology. An incidence of a primary toxoplasma infection of >1/1,000 pregnancies in this pilot study justifies a larger study.

Adolescent↗

PubMed1997

[Congenital toxoplasmosis and seroconversion at the end of pregnancy: clinical observations].

We report seven cases of subclinical congenital toxoplasmosis secondary to maternal primary infections. Mothers were infected between two and four weeks prior to delivery. The diagnostic criteria of congenital infections included: IgM antibody (Ab) (1 case); IgM and IgA Ab (1 case); a real IgG seroconversion in the neonatal and postnatal samples (3 cases); persistence of IgG Ab beyond 6 months post-delivery (2 cases). A treatment was initiated, including a combination of pyrimethamine + sulfadiazine (6 cases); trimethoprim + sulfamethoxazole (1 case). This retrospective study suggests that it is important to screen the non-immune pregnant women until delivery. We confirmed the usefulness of a combination of isotypes of antibodies for the accurate assessment of congenital infection. Finally, infected infants have to be treated and monitored clinically and immunologically during the first year of life.

Adult↗

PubMed2002

Hepatitis C virus seroconversion among young injection drug users: relationships and risks.

The present study examined reasons for the high incidence of hepatitis C virus (HCV) infection among young injection drug users (IDUs). IDUs <30 years old who tested negative for HCV antibody were enrolled in a prospective cohort. Risk factors for seroconversion were examined using time-dependent regression analyses: 48 of 195 IDUs seroconverted to HCV, for an incidence rate of 25.1/100 person-years (95% confidence interval, 18.7-32.9/100 person-years). Independent risk factors included sharing needles with an HCV-infected sex partner (borderline statistical significance, P=.11) or a person who was not a sex partner, sharing nonsterile drug-preparation equipment, pooling money with another IDU to buy drugs, and exchanging sex for money. Ubiquitous behaviors among young IDUs, such as the forming of injecting or sexual partnerships and consequent sharing of needles and drug preparation equipment, are risk factors for HCV. Interventions to reduce HCV transmission must recognize the importance of relationships on injecting risk.

Adolescent↗

PubMed2003

Supplementation with zinc, but not vitamin A, improves seroconversion to vibriocidal antibody in children given an oral cholera vaccine.

To investigate whether micronutrient supplementation could improve the vibriocidal antibody response of children to a killed oral cholera vaccine, 2-5-year-old children were randomly assigned to receive vitamin A and zinc (AZ group), vitamin A and a placebo (A group), zinc and a placebo (Z group), or both placebos (P group). All children received 2 doses of the vaccine. The number of children who had a > or = 4-fold increase in vibriocidal antibody was significantly greater in the AZ group than in the P group (P = .025-.028). Factorial analysis suggested that the proportion of children with a > or = 4-fold increase in vibriocidal antibody titer was significantly greater in the zinc-supplemented groups than in the groups that did not receive zinc (P = .013-.048) and that vitamin A supplementation did not have a significant effect. Thus, supplementation with zinc improves seroconversion to vibriocidal antibody and, hence, has the potential to improve the efficacy of oral cholera vaccine in children.

Administration, Oral↗

PubMed2004

Clearance of hepatitis C viremia associated with cellular immunity in the absence of seroconversion in the hepatitis C incidence and transmission in prisons study cohort.

Understanding the earliest virological and immunological events in acute hepatitis C virus (HCV) infection may provide insight into the determinants of protective immunity. Four cases of HCV viremia with subsequent viral clearance, but without biochemical hepatitis or anti-HCV seroconversion, are reported from a prospective cohort study of prison inmates. Two of the subjects who developed sustained viremia were assessed for production of interferon (IFN)- gamma, by use of the enzyme-linked immunospot (ELISPOT) method and by assessment of HCV cytotoxic T lymphocyte (CTL) activity, CD4 lymphocyte proliferative responses, HCV load, and genotype. After 2-6 months of viremia, all 4 subjects cleared serum HCV RNA. Specific cellular responses were detected in both of the subjects who were assessed, and production of IFN- gamma was demonstrated in one subject. All subjects had weak, but consistent, serological reactivity against HCV nonstructural proteins on immunoblot testing, despite repeatedly nonreactive HCV ELISA tests. These cases highlight the potential for cellular immune responses against HCV to facilitate viral clearance, responses that may model those required for effective HCV vaccination.

Adult↗

PubMed1997

Detection of infection with human immunodeficiency virus type 1 before seroconversion: correlation with clinical symptoms and outcome.

Early (pre-seroconversion) infection with human immunodeficiency virus type 1 (HIV-1) was identified in 50 of 267 participants in the Multicenter AIDS Cohort Study. These 50 men had a positive EIA result, which detected IgM antibody (n = 35), p24 antigen, or serum HIV RNA (n = 15) at their last "seronegative" visit. At that visit, the mean CD4 lymphocyte number (890/mm3 vs. 1038/mm3) was significantly lower than in men who subsequently seroconverted but had no evidence of early infection. The decline in CD4 cells was slower and the duration of AIDS-free time longer in the 19 men who were symptomatic in comparison to the 31 asymptomatic men with early infection, but differences were not significant.

Acquired Immunodeficiency Syndrome↗

PubMed1998

Association between cytomegalovirus seroconversion and upper genital tract infection among women attending a sexually transmitted disease clinic: a prospective study.

To study relationships between acquisition of cytomegalovirus (CMV), sexual activity, and sexually transmitted diseases, 245 CMV-seronegative women were followed (median, 23 months) in a sexually transmitted disease clinic between 1980 and 1988. Thirty-six (15%) seroconverted (10%-12%/year). At entry, seroconverters were younger (P = .03), were younger at sexual debut (P = .004), and had more sex partners (P = .004) than non-seroconverters. During follow-up, seroconverters had more sex partners, had more new sex partners (P = .05 for each), and were more likely to have gonorrhea, chlamydia, or pelvic inflammatory disease. At seroconversion, Chlamydia trachomatis was isolated from cervix in 14%, versus 3% of non-seroconverters (odds ratio [OR], 4.5; 95% confidence interval [CI], 1.3-14.9). Signs of upper genital tract infection were present in 8% of seroconverters versus 2% of non-seroconverters (OR, 4.7; 95% CI, 1.0-21.8). Acquisition of CMV in these women was associated with sexual activity, sexually transmitted diseases, and signs of upper genital tract infection.

Adolescent↗

PubMed1997

Rapid disease progression without seroconversion following primary human immunodeficiency virus type 1 infection--evidence for highly susceptible human hosts.

A patient is described who rapidly progressed from primary human immunodeficiency virus (HIV) type 1 infection to death without seroconversion but with consistently high plasma viremia. His asymptomatic sex partner had been HIV-1 seropositive for >8 years prior to transmission. Analysis of viral sequences from these subjects and controls confirmed the transmission event. Although the biologic properties of the patient's virus were unremarkable, he had poor functional immune responses to HIV and an HLA haplotype associated with rapid disease progression. The disparity between immune responses and clinical course in this transmission pair, coupled with infection with an unremarkable HIV-1 isolate, underscores the crucial importance of host factors in HIV-1 pathogenesis.

Adult↗

PubMed2002

Vascular endothelial growth factor levels in serum do not increase following HIV type 1 and HHV8 seroconversion and lack correlation with AIDS-related Kaposi's sarcoma.

The utility of vascular endothelial growth factor (VEGF) concentrations in serum as a predictive marker for AIDS-KS was studied. Sera were obtained from 40 homosexual men who seroconverted for HIV-1 and HHV8 prior to or during their participation in the Amsterdam Cohort Studies (1984-2000). We designed an ELISA to detect VEGF and measured VEGF prior to either infection, at HIV-1 and HHV8 seroconversion, after both infections, at AIDS-KS diagnosis (n = 11), and in the most recently available serum sample. The geometric mean serum VEGF concentration was 81.5 pg/ml in those with AIDS-KS and 80.4 pg/ml in those with AIDS but without KS. Median serum VEGF concentrations did not differ between the time points described above. Higher VEGF concentrations in serum were observed at higher CD4(+) cell counts. Serum concentrations of VEGF were not influenced by HIV-1 or HHV8 infection or by the conditions leading to AIDS-KS. Sequential measurement of VEGF in serum is not expected to contribute to the prediction or therapeutic monitoring of AIDS-KS.

Acquired Immunodeficiency Syndrome↗

PubMed1988

Heterophil-negative mononucleosis-like illnesses with atypical lymphocytosis in patients undergoing seroconversions to the human immunodeficiency virus.

The authors present data from four patients with acute heterophil-negative mononucleosis-like illnesses who were initially thought to have primary Epstein-Barr virus (EBV) infections but eventually were shown to be seroconverting to the human immunodeficiency virus (HIV). Widespread lymphadenopathy and blood smears indistinguishable from those typically encountered in the acute phase of infectious mononucleosis were present in all cases. There were also varying combinations of fever, sore throat, and malaise, as well as mild abnormalities of hepatic function and elevated cold agglutinins (anti-I). Anti-HIV was detected by both enzyme-linked immunosorbent assay and Western blot techniques in all cases, with increasing titers noted in two of three serially studied cases. In one patient, a dual infection with the hepatitis B virus was also documented. Diagnostic possibilities in patients with acute mononucleosis-like illnesses dominated by prominent lymphadenopathy should include primary seroconversions to HIV.

Antibodies, Heterophile↗

PubMed2001

Differences in the temporal trends of HIV seroincidence and seroprevalence among sexually transmitted disease clinic patients, 1989-1998: application of the serologic testing algorithm for recent HIV seroconversion.

The authors compared temporal trends in the prevalence and incidence of human immunodeficiency virus (HIV) infection based upon 34,866 specimens from patients who attended the San Francisco, California, municipal sexually transmitted disease clinic between 1989 and 1998. HIV infection data were collected during annual blinded HIV serologic surveys. Incidence was determined by applying a serologic testing algorithm for recent HIV seroconversion that uses both a sensitive and a less sensitive enzyme immunoassay to stored HIV positive sera. The HIV seroprevalence declined from 15.2% in 1989 to 7.2% in 1998 (odds ratio per year = 0.92, 95% confidence interval (CI): 0.91, 0.94). Among homosexual men, the HIV prevalence declined from 50.9% in 1989 to 19.9% in 1998 (odds ratio per year = 0.86, 95% CI: 0.85, 0.88). The pooled seroincidence was 1.6% and did not change significantly over time (odds ratio per year = 1.0, 95% CI: 0.98, 1.1). The pooled seroincidence among homosexual men was 6.6% per year and remained steady between 1989 and 1998 (odds ratio per year = 0.99, 95% CI: 0.92, 1.1). During a dramatic, 10-year decline in seroprevalence of HIV infection, the incidence of HIV infection remained remarkably stable.

Adult↗

PubMed2004

Poliovirus vaccination during pregnancy, maternal seroconversion to simian virus 40, and risk of childhood cancer.

Before 1963, poliovirus vaccine produced in the United States was contaminated with simian virus 40 (SV40), which causes cancer in animals. To examine whether early-life SV40 infection can cause human cancer, the authors studied 54,796 children enrolled in the US-based Collaborative Perinatal Project (CPP) in 1959-1966, 52 of whom developed cancer by their eighth birthday. Those children whose mothers had received pre-1963 poliovirus vaccine during pregnancy (22.5% of the children) had an increased incidence of neural tumors (hazard ratio = 2.6, 95% confidence interval: 1.0, 6.7; 18 cases) and hematologic malignancies (hazard ratio = 2.8, 95% confidence interval: 1.2, 6.4; 22 cases). For 50 CPP children with cancer and 200 CPP control children, the authors tested paired maternal serum samples from pregnancy for SV40 antibodies using a virus-like particle enzyme immunoassay and a plaque neutralization assay. Overall, mothers exhibited infrequent, low-level SV40 antibody reactivity, and only six case mothers seroconverted by either assay. Using the two SV40 assays, maternal SV40 seroconversion during pregnancy was not consistently related to children's case/control status or mothers' receipt of pre-1963 vaccine. The authors conclude that an increased cancer risk in CPP children whose mothers received pre-1963 poliovirus vaccine was unlikely to have been due to SV40 infection transmitted from mothers to their children.

Adult↗