Groen, J.

Epstein-Barr virus and disease activity in multiple sclerosis (Article)

2005-01-01T00:00:00Z

OBJECTIVES: To study in relapsing-remitting (RR) multiple sclerosis (MS) whether exacerbations and brain activity as measured by magnetic resonance imaging (MRI) are associated with plasma levels of anti-Epstein Barr (EBV) antibodies and EBV DNA. METHODS: This was a prospective study with 73 RR MS patients followed for an average of 1.7 years with frequent neurological examination and blood sampling. Antibodies to various EBV proteins were measured by ELISA and plasma EBV DNA was measured by PCR. RESULTS: All MS patients had IgG antibodies to EBV (viral capsid antigen (VCA) and/or EBV nuclear antigen (EBNA)), irrespective whether samples were taken at stable disease or exacerbation. A significantly elevated percentage of the patients (48%) had antibodies against EBV antigens (early antigen, EA) that indicate active viral replication, compared with the age matched healthy controls (25%). Antibodies against a control herpesvirus, cytomegalovirus, were similar between the two groups. The percentage of EA positive individuals and EA titres did not differ between stable disease or exacerbation. Anti-VCA IgM was positive in three cases, unrelated to disease activity. Using a highly sensitive PCR on 51 samples taken at exacerbation visits, only three patients were found to have one timepoint with viraemia, and this viraemia was unrelated to disease activity. Of special note was the fact that anti-EA seropositive patients remained seropositive during follow up, with stable titres over time. We hypothesised that these patients may constitute a subgroup with higher disease activity, due to the triggering effect of a chronic attempt of the virus to reactivate. The EA positive group did not differ from the EA negative with respect to clinical disease activity or other characteristics. However, in the EA positive group, analysis with gadolinium enhanced MRI indicated more MRI disease activity. CONCLUSIONS: There was no evidence for increased clinical disease activity in the subgroup of MS patients with serological signs of EBV reactivation. However, the observation that chronic EBV reactivation may be associated with increased inflammatory activity as assessed by gadolinium enhanced MRI lesions should be reproduced in a larger and independent dataset.

Elevated levels of total and dengue virus-specific immunoglobulin E in patients with varying disease severity (Article)

2003-05-01T00:00:00Z

The kinetics of total and dengue virus-specific immunoglobulin E (IgE) were studied in serial serum samples obtained from 168 patients, 41 of whom suffered from primary dengue virus infection and 127 suffered from secondary dengue virus infection. Seventy-one patients were classified as dengue fever, 30 as dengue hemorrhagic fever, and 67 as dengue shock syndrome. A control group included single serum samples from patients with a herpes virus infection (n = 14), non-dengue febrile patients (n = 10), and healthy blood donors (n = 10). Patients with dengue virus infection had higher levels of total and dengue virus-specific IgE than non-dengue patients (P < 0.05). Patients with secondary dengue virus infections had not significantly increased levels of both total and dengue virus-specific IgE in the acute phase of disease compared to patients with primary dengue virus infections. Dengue virus-specific IgE was significantly higher in dengue hemorrhagic fever and/or dengue shock syndrome patients compared to dengue fever and non-dengue patients (P < 0.05). In conclusion, this study showed elevated total and dengue virus-specific IgE serum antibody levels in the acute stage of disease. Therefore, measurement of both total and dengue virus-specific IgE serum antibodies can be used as an additional prognostic marker in the development of severe complications in dengue virus infections. In addition, the presence and increase of dengue virus-specific IgE serum antibodies in patients with dengue virus infections is suggestive of the pathogenetic role that IgE may play in the hemostatic disorders observed in dengue hemorrhagic fever and dengue shock syndrome.

Detection of immune-complex-dissociated nonstructural-1 antigen in patients with acute dengue virus infections (Article)

2003-01-01T00:00:00Z

Accurate and timely diagnosis of dengue virus (DEN) infections is essential for the differential diagnosis of patients with febrile illness and hemorrhagic fever. In the present study, the diagnostic value of a newly developed immune-complex dissociated nonstructural-1 (NS-1) antigen dot blot immunoassay (DBI) was compared to a commercially available DEN antigen detection kit (denKEY Blue kit; Globio Co., Beverly, Mass.) and a reverse transcription-PCR (RT-PCR) kit. Serial serum or plasma samples (n = 181) obtained from 55 acute DEN-infected patients were used. In samples obtained from 32 of these 55 DEN-infected patients, viral RNA could be detected by RT-PCR. DEN antigen was detected in only 10 of these 55 patient samples by using the denKEY kit. When these samples were treated with acid to release the immune-complex-associated NS-1 antigen for detection by DBI, 43 of these 55 patients were found to be positive for DEN NS-1 antigen. In nondissociated samples, 22 of these patients were found to be positive by the DBI. In the presence of DEN-specific immunoglobulin M antibodies, both viral RNA and DEN (NS-1) antigen could be detected. The number of positive samples identified by RT-PCR and DBI from these patients with primary DEN infections varied between 28 and 78%. In secondary DEN infections, the number of samples that tested positive by the DBI after immune-complex dissociation (DIS-DBI) was 25% higher than the number of samples that tested positive by RT-PCR and was 35% higher than that determined by nondissociated antigen (NDIS-DBI) detection. We conclude that the denKEY kit has limited diagnostic value for acute DEN infections compared to the RT-PCR and the NDIS-DBI and DIS-DBI methods. We clearly demonstrate that in secondary DEN infections the dissociation of NS-1 immune complexes is essential for early diagnosis of DEN infections.

Detection of Immune-Complex Dissociated Nonstructural-1 (NS-1) Antigen in Patients with Acute Dengue Virus Infections (Article)

2003-01-01T00:00:00Z

Cross-reactive anti-galactocerebroside antibodies and Mycoplasma pneumoniae infections in the Guillain-Barré syndrome. (Article)

2002-09-01T00:00:00Z

Anti-galactocerebroside (GalC) antibodies are reported to be present in GBS patients with preceding Mycoplasma pneumoniae (MP) infection. We investigated the presence of anti-GalC reactivity in serum of a large group of GBS patients using ELISA and compared this with healthy controls and individuals with an uncomplicated MP infection. Anti-GalC antibody reactivity was present in 12% of the GBS patients. Furthermore, anti-GalC antibodies were associated with MP infections, a relatively mild form of the disease and demyelinating features. Anti-GalC antibodies cross-reacted with MP antigen. In conclusion, anti-GalC antibodies in GBS patients may be induced by molecular mimicry with MP.

Incidence and risk factors of probable dengue virus infection among Dutch travelers to Asia. (Article)

2002-06-17T00:00:00Z

We studied the incidence of dengue virus (DEN) infections in a cohort of Dutch short-term travellers to endemic areas in Asia during 1991-92. Sera were collected before and after travel. All post-travel sera were tested for DEN immunoglobulin M (IgM) [IgM capture (MAC)-enzyme-linked immunosorbent assay (ELISA)] and IgG (indirect ELISA). Probable DEN infection was defined as IgM seroconversion or a fourfold rise in IgG ratio in the absence of cross-reaction with antibody to Japanese encephalitis virus (JEV). Infections were considered clinically apparent in case of febrile illness (> 24 H) with headache, myalgia, arthralgia or rash. Probable DEN infection was found in 13 of 447 travellers (incidence rate 30/1000 person-months, 95% CI 17.4-51.6). One infection was considered secondary; no haemorrhagic fever occurred. The clinical-to-subclinical infection rate was 1:3.3. The risk of infection showed marked seasonal variation. DEN infections are frequent in travellers to endemic areas in Asia; most remain subclinical.

Role of picornaviruses in flu-like illnesses of adults enrolled in an oseltamivir treatment study who had no evidence of influenza virus infection (Article)

2002-02-18T00:00:00Z

The primary objective of this study was to determine the role of picornavirus in flu-like episodes (temperature of > or =38.0 degrees C plus one respiratory and one constitutional symptom) among otherwise healthy adults enrolled in a placebo-controlled, double-blind, randomized oseltamivir treatment study. Combined nasal and pharyngeal swabs were collected at baseline for influenza cultures and picornavirus reverse transcription (RT)-PCR. In addition, acute- and convalescent-serum samples were obtained for serological studies of common respiratory pathogens. From a total of 719 subjects enrolled in the clinical trial within 36 h of the onset of symptoms, 475 (66%) had evidence of recent influenza A or B virus infections by means of culture and/or serological testing. Of the 244 remaining patients, 36 (15%) presented a seroconversion for at least one of the common respiratory viruses or atypical pathogens. An RT-PCR assay for the picornavirus 5" noncoding region (NCR) was positive in a subset of 15 (19%) of 78 patients with flu-like illnesses of undetermined etiology. Sequence analysis of the picornavirus 5" NCR amplicons revealed that 14 (93%) of them had greater homology to rhinoviruses, whereas 1 (7%) was related to enteroviruses. Interestingly, median total symptom scores and oral temperatures of picornavirus-positive patients (n = 15) and placebo-treated influenza virus-positive patients (n = 161) were similar over a 3-week period. We conclude that, among the influenza virus-negative preselected cases of this study, rhinoviruses were relatively frequent pathogens associated with important respiratory and systemic symptoms.

Role of picornaviruses in flu-like illnesses of adults enrolled in an oseltamivir treatment study who had no evidence of influenza virus infection (Article)

2002-01-01T00:00:00Z

Retrospective identification of three undiagnosed cases of measles encephalitis (Article)

2002-01-01T00:00:00Z

It has long been recognised that neuroinvasion may occur as a rare complication of measles. According to cases reported in the medical literature [1], measles virus (MV) can persist in the central nervous system producing chronic neurological disease without systemic viremia [2, 3]. In most industrialised countries, the introduction of live attenuated measles vaccines has resulted in the virtual disappearance of measles as a common childhood disease and strongly reduced the numbers of patients with MV-related neurological disease. However, measles did not completely disappear: occasional clinical cases are still observed due to importation of MV from endemic areas [4], and larger outbreaks continue to occur amongst clusters of unvaccinated individuals [5]. It is difficult to assess how many people are exposed to wild-type MV as a result of these cases, but the virus is only rarely considered as a possible cause of neurological symptoms.

Measles in suburban Khartoum: an epidemiological and clinical study. (Article)

2002-01-01T00:00:00Z

Clinical and epidemiological data were collected from 187 clinically diagnosed measles patients in Haj Yousif area, suburban Khartoum. Laboratory tests confirmed the diagnosis in 141 (75%) of the cases, but demonstrated that in 46 (25%) patients the clinical symptoms were not caused by an acute measles virus (MV) infection. According to their vaccination card, 59% of the laboratory-confirmed measles cases had been vaccinated for measles. Compared with non-measles rash disease cases, confirmed measles cases more often had severe illness (P < 0.0001), were dehydrated (P=0.01) at presentation and less likely to recover without complications [OR 0.19 (95% CI 0.09, 0.39)]. There was no difference in death rate (P=0.20). Underweight [weight-for-age Z score (WAZ)

Kinetics of dengue virus-specific serum immunoglobulin classes and subclasses correlate with clinical outcome of infection. (Article)

2001-12-17T00:00:00Z

The kinetics of dengue virus (DEN)-specific serum immunoglobulin classes (immunoglobulin M [IgM] and IgA) and subclasses (IgG1 to IgG4) were studied in patients suffering from dengue fever (DF), dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS). Serum samples from non-DEN febrile patients were included as controls. IgM, IgG1, and IgG3 serum antibodies were the predominant immunoglobulins throughout the course of illness in all three patient groups. In contrast, IgA antibodies were significantly higher in the acute phase in DSS patients compared to those in DF patients (P < 0.05). The levels of IgG1 differed significantly between patients with DF and those with DHF and DSS (P < 0.05). A significant difference was also found in IgG3 levels between DF patients and DHF patients (P < 0.05) but not between DF patients and DSS patients. Finally, levels of IgG4 antibodies differed significantly between DF patients and DSS patients (P < 0.05). Collectively, these data show that increased levels of DEN-specific IgA, IgG1, and IgG4 serum antibodies are risk markers for the development of DHF and DSS and that their measurement may provide valuable guidance for early therapeutic intervention. AD - Laboratory for Exotic Viral Infections, Institute of Virology, Erasmus Medical Centre Rotterdam, Rotterdam, The Netherlands.

A newly discovered human pneumovirus isolated from young children with respiratory tract disease. (Article)

2001-07-09T00:00:00Z

From 28 young children in the Netherlands, we isolated a paramyxovirus that was identified as a tentative new member of the Metapneumovirus genus based on virological data, sequence homology and gene constellation. Previously, avian pneumovirus was the sole member of this recently assigned genus, hence the provisional name for the newly discovered virus: human metapneumovirus. The clinical symptoms of the children from whom the virus was isolated were similar to those caused by human respiratory syncytial virus infection, ranging from upper respiratory tract disease to severe bronchiolitis and pneumonia. Serological studies showed that by the age of five years, virtually all children in the Netherlands have been exposed to human metapneumovirus and that the virus has been circulating in humans for at least 50 years.

Combination of reverse transcriptase PCR analysis and immunoglobulin M detection on filter paper blood samples allows diagnostic and epidemiological studies of measles. (Article)

2001-01-30T00:00:00Z

As measles control and elimination campaigns progress, laboratory confirmation of clinically diagnosed measles cases becomes increasingly important. However, in many tropical countries collection and storage of clinical specimens for this purpose are logistically complicated. In this study it is shown that blood samples spotted on filter paper are suitable for the laboratory diagnosis of measles using a combination of reverse transcriptase PCR (RT-PCR) analysis and immunoglobulin M (IgM) detection. First, it was shown that in vitro measles virus (MV)-infected cells diluted in human blood and spotted on filter paper can be detected by RT-PCR. Small amounts of infected cells remained detectable after 25 weeks of storage of the filter paper at room temperature, 4 weeks at 37 degrees C, or 2 weeks at 45 degrees C. Subsequently, this RT-PCR was applied to filter paper blood samples collected from 117 clinically diagnosed measles patients in Sudan in 1997 and 1998. Prior laboratory diagnosis had confirmed 90 cases as acute MV infections, while 27 proved to be nonmeasles rash disease cases. Positive RT-PCR signals were detected in filter paper blood samples of 43 of the 90 confirmed cases (48%) but in none of the 27 nonmeasles cases. In addition, MV-specific IgM levels measured in reconstituted filter paper samples correlated well with those measured in plasma samples. Measles diagnosis based on the combination of filter paper RT-PCR and IgM detection had a sensitivity and specificity of 99 and 96%, respectively. An advantage of this diagnostic approach is that sequencing of RT-PCR products allows phylogenetic analysis of the MV strain involved.

Prevalence and association between herpes simplex virus types 1 and 2-specific antibodies in attendees at a sexually transmitted disease clinic (Article)

2001-01-01T00:00:00Z

BACKGROUND: Seroprevalence of herpes simplex virus type 1 (HSV-1) and HSV-2 was determined in 1993 and 1998 in a randomly selected study group of 1024 and 654 attendees, respectively, at the sexually transmitted disease (STD) clinic of the University Hospital Rotterdam-Dijkzigt, The Netherlands. Correlations of HSV-1 and HSV-2 seropositivity were investigated. The relationship between HSV-1 and HSV-2 antibodies was also studied. METHODS: Data were collected in a cross-sectional study from February 1993 until February 1994 and from January 1998 until December 1998. Glycoprotein G (gG) HSV type specific serum IgG was determined. RESULTS: Seroprevalence of HSV-1 was 68% versus 59% (1993 versus 1998, chi(2)-test P < 0.001), of HSV-2 it was 30% versus 22% (1993 versus 1998, chi(2)-test P < 0.001). Using logistic regression analyses, HSV-1 and HSV-2 seropositivity were significantly associated with age and ethnicity in both groups. In 1993, HSV-1 seropositivity also correlated with lower level of education and female gender, whereas in 1998 it correlated with 'number of sexual partners in the past 6 months' and 'present diagnosis of STD'. In both groups, HSV-2 seropositivity was also more prevalent in females and related to sexual lifestyle variables. In an exposure-disease model, HSV-1 seropositivity was not correlated with HSV-2 seropositivity (odds ratio 1993 = 1.1, 95% CI : 0.8--1.7; odds ratio in 1998 = 1.0, 95% CI : 0.5--1.8). CONCLUSIONS: Seroprevalence of HSV-1 and HSV-2 is falling among STD clinic attendees in Rotterdam. A changing pattern of risk factors for HSV-1 seropositivity indicates increasing sexual transmission of HSV-1. Seropositivity for HSV-2 correlated with known risk factors. A previous HSV-1 infection does not reduce susceptibility to subsequent genital HSV-2 infections.

Characterisation of a recently isolated lyssavirus in frugivorous zoo bats. (Article)

2000-10-09T00:00:00Z

Summary. In July 1997 a lyssavirus was isolated in Denmark from a colony of Egyptian flying foxes (Rousettus aegyptiacus) originating from a Dutch zoo. Sequencing of a 400 nucleotides coding region of the nucleoprotein and of a major part of the G-protein ectodomain encoding region of the newly isolated virus, revealed a very high similarity with European Bat Lyssavirus subtype 1a (EBL- 1a). For characterisation of the recently isolated lyssavirus in frugivorous zoo bats, 16 frugivorous bats (Rousettus aegyptiacus) of the same colony and 80 mice were experimentally infected with the Rousettus isolate or with a well defined EBL-1a strain isolated from a Dutch insectivorous bat (Eptesicus serotinus). Inoculation viruses were titrated in mice to determine LD50‘s of both isolates. Clinical signs of inoculated bats were recorded during 6 weeks. After showing neurological signs or at the end of the experimental infection all animals were euthanized. During the experimental infection sera and various tissues of inoculated bats were collected. Immunoassays, mouse inoculation tests (MIT) and polymerase chain reaction (PCR) were employed for detection of lyssavirus specific antibodies, antigen or RNA. Five bats inoculated with the Rousettus isolate and 2 bats inoculated with the Eptesicus isolate showed neurological signs. The remaining 9 bats survived and cleared the virus; at least under the detection limit of the used assays. Despite a much higher pathogenicity of the Rousettus isolate observed in mice, LD25’s in bats were quite the same for the 2 isolates. The pathogenicity of both isolates suggested that like many other mammals, Rousettus aegyptiacus bats could be victims of lyssavirus infection besides reservoir hosts of infectious EBL1a. There was no significant difference in detecting the different lyssavirus isolates in Rousettus aegyptiacus bats.Anemployed immunoperoxidase staining (IP) method was very useful for sensitive detection and localization of lyssavirus antigen in histologic preparates.

Evaluation of two commercially available immunoassays for the detection of hantavirus antibodies in serum samples. (Article)

2000-09-01T00:00:00Z

BACKGROUND: hantaviruses are members of the family Bunyaviridae and the spectrum of clinical symptoms in humans may vary from sub-clinical to severe haemorrhagic fever with renal syndrome (HFRS) or pulmonary syndrome (HPS). Several serotypes have been described from which at least five are pathogenic to humans. Each serotype has a different animal reservoir and geographical distribution. In the acute phase of the disease the clinical diagnosis may be confirmed by serology or by polymerase-chain reaction (PCR). OBJECTIVE: to evaluate two commercially available immunoassays using sera from hantavirus suspected and non-hantavirus patients: an enzyme immunoassay (EIA) developed by MRL Diagnostics, for the detection of immunoglobulins M (IgM) and G (IgG) against several hantavirus serotypes and an indirect immunofluorescence assay (IFA) from Progen, based on slides coated with Hantaan virus (HNTV) and Puumala virus (PUUV), infected cells. STUDY DESIGN: a total of 145 serum samples were used for this study. The serum panel included serum samples from patients suspected of mild (n=91), severe (n=10) HFRS and patients with other viral infections (n=44). RESULTS: the agreement between the MRL EIA and the Progen IFA for the detection of IgM and IgG serum antibodies ranged from 87 to 91%, respectively. In the non-hantavirus group one out of 44 samples was positive by the Progen HNTV IgM IFA, none in the Progen PUUV IFA and two samples in the MRL IgM EIA, resulting in specificities of 98, 100 and 95%, respectively. The sensitivities and specificities of the MRL EIAs compared to the Progen overall PUUV and HNTV IFAs were 90 and 91% for IgM, respectively, and 96% for IgG in both immunoassays. CONCLUSIONS: the MRL EIA proved to be relatively sensitive and specific assay for the serological diagnosis of mild and severe HFRS.

Protective immunity in macaques vaccinated with a modified vaccinia virus Ankara-based measles virus vaccine in the presence of passively acquired antibodies (Article)

2000-05-02T00:00:00Z

Recombinant modified vaccinia virus Ankara (MVA), encoding the measles virus (MV) fusion (F) and hemagglutinin (H) (MVA-FH) glycoproteins, was evaluated in an MV vaccination-challenge model with macaques. Animals were vaccinated twice in the absence or presence of passively transferred MV-neutralizing macaque antibodies and challenged 1 year later intratracheally with wild-type MV. After the second vaccination with MVA-FH, all the animals developed MV-neutralizing antibodies and MV-specific T-cell responses. Although MVA-FH was slightly less effective in inducing MV-neutralizing antibodies in the absence of passively transferred antibodies than the currently used live attenuated vaccine, it proved to be more effective in the presence of such antibodies. All vaccinated animals were effectively protected from the challenge infection. These data suggest that MVA-FH should be further tested as an alternative to the current vaccine for infants with maternally acquired MV-neutralizing antibodies and for adults with waning vaccine-induced immunity.

Prevalence of serum antibodies against bloodborne and sexually transmitted agents in selected groups in Somalia. (Miscellaneous)

2000-02-01T00:00:00Z

Serological and virological characterization of clinically diagnosed cases of measles in suburban Khartoum (Article)

2000-01-01T00:00:00Z

Measles continues to be a major childhood disease in terms of global morbidity and mortality. In the main areas of its endemicity the only available means of diagnosis are based on clinical criteria: the presence of a maculopapular rash and fever accompanied by cough, coryza, and/or conjunctivitis. We have studied 38 clinically diagnosed cases of measles in Khartoum, Sudan, by means of serology, reverse transcriptase PCR (RT-PCR) on throat swabs and virus isolation from lymphocytes. On the basis of serology, 28 patients were diagnosed as having an acute measles virus (MV) infection, while in 10 cases the clinical symptoms proved to have other causes. It was shown that in cases with low serum immunoglobulin M (IgM) levels, an additional measurement of IgG or virus-neutralizing antibodies was necessary to discriminate between patients with an acute MV infection sampled during an early stage of the disease and patients who had experienced an MV infection in the more distant past. The serological laboratory diagnosis was validated by an MV-specific RT-PCR: for all confirmed measles cases tested a fragment of the correct size which hybridized with a third MV-specific primer could be amplified, while all serologically negative cases were also RT-PCR negative. MV could be isolated from 17 out of 23 of the serologically confirmed cases, demonstrating that virus isolation is less reliable as a diagnostic tool than serology or RT-PCR. This study stresses the urgent need for a rapid diagnostic field test for measles.

Protective immunity in macaques vaccinated with a modified vaccinia virus Ankara-based measles virus vaccine in the presence of passively acquired antibodies (Article)

2000-01-01T00:00:00Z

Evaluation of six immunoassays for detection of dengue virus-specific immunoglobulin M and G antibodies (Article)

2000-01-01T00:00:00Z

The performance of six commercially available immunoassay systems for the detection of dengue virus-specific immunoglobulin M (IgM) and IgG antibodies in serum was evaluated. These included two IgM and IgG enzyme immunoassays (EIA) from MRL Laboratories and PanBio, a rapid immunochromatographic test (RIT) from PanBio, immunofluorescence assays (IFA) from Progen, a dot blot assay from Genelabs, and a dipstick EIA from Integrated Diagnostics (INDX). For this study a panel of 132 serum samples, including 90 serum samples from patients with suspected dengue virus infection and 42 serum samples from patients with other viral infections, was used. In addition, serial serum samples from two monkeys experimentally immunized and challenged with dengue virus type 2 were used. Results were considered conclusive when concordant results were obtained with four of the six antibody-specific assays. Based on this definition, the calculated overall agreement for the human serum samples for the respective IgM immunoassays was 97% (128 of 132), with 34% (45 of 132) positive serum samples, 63% (83 of 132) negative samples, and 3% of samples (4 of 132) showing discordant results. The calculated overall agreement for the IgG assays was 94% (124 of 132), with 49% (65 of 132) positive, 45% (59 of 132) negative, and 6% (8 of 132) discordant results, respectively. The sensitivities of the dengue virus-specific assays evaluated varied between 71 and 100% for IgM and between 52 and 100% for IgG, with specificities of 86 to 96% and 81 to 100%, respectively. The relative sensitivities of the respective IgM assays measured with the monkey serum samples were comparable with those obtained with 12 serial serum samples from humans. Overall performance, based on the sum of the agreement, sensitivity, specificity, and Kappa statistics of the IgM and IgG immunoassays, showed that the antibody detection systems from INDX and Genelabs and the MRL and PanBio EIA are useful and reliable assays for dengue virus serodiagnosis.

Diagnostic value of dengue virus-specific IgA and IgM serum antibody detection. (Article)

1999-11-01T00:00:00Z

The diagnostic value of dengue virus (DV)-specific immunoglobulin A (IgA) serum antibody detection, by an indirect immunofluorescence assay (IFA) was evaluated. For this study, the kinetics of DV-specific IgA serum antibodies was analysed in two experimentally immunised macaques, paired samples from 35 patients suspected of a primary or secondary DV infection, paired sera from patients with high levels of IgA specific antibodies against influenza virus (n = 15), sera from patients with other viral infections (n = 40) and healthy blood donors (n = 10), which served as controls. The presence of DV-specific IgA serum antibodies in humans and in monkeys was compared with that of DV-specific IgM demonstrated in a capture enzyme-linked immunosorbent assay (ELISA). The development of DV-specific IgA and IgM antibodies in macaques proved to be similar to that observed in humans with a DV infection. In sera obtained from suspected primary DV patients during the acute phase and convalescent phase, DV-specific IgA was detected in 1/6 (17%) and 6/6 (100%), whereas IgM was detected in 4/6 (67%) and 5/6 (83%), respectively. In sera from suspected secondary DV patients during the acute phase and convalescent phase, DV-specific IgA was detected in 18/29 (62%) and 28/29 (97%), whereas IgM was detected in 20/29 (69%) and 28/29 (97%), respectively. The control group consisted of five paired serum samples from yellow fever vaccinated individuals and a patient with acute tick-borne encephalitis, 15 paired serum samples from patients with high levels of IgA antibodies specific for influenza virus and 40 serum samples from patients with specific IgM antibodies against other viruses. Ten serum samples from healthy blood donors were included. Among the control serum samples, in one patient, both DV-specific IgA and IgM antibodies were present, and in three sera DV-specific IgM antibodies could be demonstrated. These data suggest that detection of DV-specific IgA serum antibodies by IFA may have additional value for the diagnosis of DV infection.

An outbreak of West Nile fever among migrants in Kisangani, Democratic Republic of Congo. (Article)

1999-01-01T00:00:00Z

In February 1998, an outbreak of acute febrile illness was reported from the Kapalata military camp in Kisangani, the Democratic Republic of Congo. The illness was characterized by an acute onset of fever associated with severe headache, arthralgia, backache, neurologic signs, abdominal pain, and coughing. In 1 individual, hemorrhagic manifestations were observed. The neurologic signs included an altered level of consciousness, convulsions, and coma. Malaria was initially suspected, but the patients showed negative blood films and failed to respond to antimicrobial drugs. A total of 35 sera collected from the military patients in the acute phase were tested for the presence of IgM against vector-borne agents. Serum IgM antibodies against West Nile fever virus were found in 23 patients (66%), against Chikungunya virus in 12 patients (34%), against dengue virus in 1 patient (3%), and against Rickettsia typhi in 1 patient (3%). All sera were negative for IgM antibody against Rift Valley fever virus, Crimean Congo hemorrhagic fever virus, and Sindbis virus. These data suggest that infections with West Nile fever virus have been the main cause of the outbreak.

An outbreak of West Nile fever among migrants in Kisangani, Democratic Republic of Congo (Article)

1999-01-01T00:00:00Z

Comparison of two enzyme-linked immunosorbent assays and one rapid immunoblot for detection of herpes simplex virus type 2-specific serum antibodies. (Article)

1998-01-01T00:00:00Z

Comparison of two enzyme-linked immunosorbent assays and one rapid immunoblot assay for detection of herpes simplex virus type 2-specific antibodies in serum.

A case of human rabies in The Netherlands. (Letter To Editor)

1998-01-01T00:00:00Z

Comparison of two enzyme-linked immunosorbent assays and one rapid immunoblot assay for detection of herpes simplex virus type 2-specific antibodies in serum (Article)

1998-01-01T00:00:00Z

The sensitivities and specificities of three immunoassays for the detection of herpes simplex virus type 2 (HSV-2)-specific immunoglobulin G antibodies in serum, including the one-strip rapid immunoblot assay (RIBA; Chiron Corporation) and two indirect enzyme immunosorbent assays (EIA; Gull Laboratories and Centocor), were compared by testing a panel of 1,250 serum samples from individuals attending an outpatient clinic for sexually transmitted diseases. A qualitative agreement among the three assays was observed with 1,080 serum samples (86.4%); 291 of the serum samples (23.3%) were positive, 789 samples (63.1%) were negative, and 170 serum samples (13.6%) gave a discordant result. Results were considered conclusive when a concordant result was obtained with two of three assays. The sensitivities and specificities of the RIBA, the Gull EIA, and the Centocor EIA proved to be 99.2, 99.7, and 89.9% and 97.1, 96.7, and 99.3%, respectively. These results indicate that the Chiron RIBA and the Gull EIA are especially useful and reliable for the detection of HSV-2-specific antibodies in serum.

Use of recombinant nucleoproteins in enzyme-linked immunosorbent assays for detection of virus-specific immunoglobulin A (IgA) and IgG antibodies in influenza virus A- or B-infected patients (Article)

1998-01-01T00:00:00Z

The nucleoprotein genes of influenza virus A/Netherlands/018/94 (H3N2) and influenza virus B/Harbin/7/94 were cloned into the bacterial expression vector pMalC to yield highly purified recombinant influenza virus A and B nucleoproteins. With these recombinant influenza nucleoproteins, enzyme-linked immunosorbent assays (ELISAs) were developed for the detection of influenza virus A- and B-specific immunoglobulin A (IgA) and IgG serum antibodies. Serum samples were collected at consecutive time points after the onset of clinical symptoms from patients with confirmed influenza virus A or B infections. Nucleoprotein-specific IgA antibodies were detected in 41.2% of influenza virus A-infected patients and in 66. 7% of influenza virus B-infected patients on day 6 after the onset of clinical symptoms. In serum samples taken on day 21 (influenza virus A-infected patients) or day 28 (influenza virus B-infected patients), nucleoprotein-specific IgA antibodies could be detected in 58.8 and 58.3% of influenza virus A- and B-infected patients, respectively. At the same time, IgG antibody rises were detected in 88.2% of influenza virus A-infected patients and in 95.8% of influenza virus B-infected patients. On comparison, hemagglutination inhibition assays detected antibody titer rises in 81.3 and 72.7% of patients infected with influenza viruses A and B, respectively. In contrast to the detection of nucleoprotein-specific IgG antibodies or hemagglutination-inhibiting antibodies, the detection of nucleoprotein-specific IgA antibodies does not require paired serum samples and therefore can be considered an attractive alternative for the rapid serological diagnosis of influenza.

Respiratory syncytial virus specific serum antibodies in infants under six months of age: limited serological response upon infection. (Article)

1997-01-01T00:00:00Z

The decline of maternal respiratory syncytial virus (RSV) specific serum antibodies was studied in 45 children during the first 6 months of life, using a virus neutralization assay and competition ELISAs measuring fusion protein and glycoprotein specific antibodies. In all children RSV neutralizing antibodies were demonstrated at birth, with titers ranging from 33 to 1382. The calculated mean half life of these antibodies was 26 days. Furthermore, in a group of 38 children with suspected RSV infection, all younger than 6 months of age on admission, the diagnostic value of serological assays was evaluated. In 32 children RSV infection was confirmed by virus isolation, direct immune fluorescence and RT-PCR. In 7 patients of this group a significant titer rise in virus neutralization assay was demonstrated. Six additional RSV infected children could be identified by showing the presence of RSV-specific IgM or IgA serum antibodies or by showing an increase in fusion protein or glycoprotein specific antibodies. All serological tests together identified 13 (41%) of the 32 RSV infected patients. It is concluded that in children of this age group, which represent the majority of patients hospitalized with RSV infections, serological assays not only have a limited diagnostic value but are of limited value for sero-epidemiological studies.

Morbillivirus in monk seal mass mortality (Article)

1997-01-01T00:00:00Z

Letter

Acute renal failure due to Leptospirosis grippotyphosa. (Letter To Editor)

1997-01-01T00:00:00Z

Hantavirus infections in The Netherlands (Doctoral Thesis)

1996-01-10T00:00:00Z

During the Korean war between 1951-1953, an epidemic occurred among United Nations sanctioned military troops, characterized by fever, haemorrhages, shock and renal failure with a case fatality rate of up to 15%. This disease became known as Korean haemorrhagic fever [Smadel, 1951; Earle, 1954]. Despite extensive investigations at that time no etiologic agent could be identified. In the far east the oldest suggestive description of a similar disease had been made as early as 1000 years ago in a Chinese medicine book [Lee, 1982a]. During the American Civil War between 1862-1866 epidemics of "general dropsy" with renal involvement were noted among northern army troops. This disease was later called "Bright's disease" [Brown, 1916]. In Europe the first descriptions of the disease appeared in the early 1900's, after outbreaks in Russia and Scandinavia [Mayer, 1952; Myhrman, 1934; Zetterholm, 1934]. The Russians called the disease haemorrhagic nephroso-nephritis and the Scandinavians named it nephropathia epidemica (NE). During the trench-warfare of World War I in Europe, several epidemics of NE-like disease occurred among British, French and German troops. In the army medical records of the respective countries this "newly" described disease became known as "trench-nephritis", "nephrite de guerre" and "Kriegsnephritis" [Brown, 1916; Ameuille, 1916; Ullman, 1916]. In World War II several thousands of cases of "Kriegsnephritis" occurred among German troops in northern Finland [Stuhlfauth, 1943; Hortling, 1946]. Gajdusek postulated already in 1962 that all the above mentioned diseases were caused by a single agent or a closely related group of agents [Gajdusek, 1962]. In 1978, more than 25 years after the end of the Korean war, Lee and co-workers isolated the etiologic agent of Korean haemorrhagic fever, - Hantaan virus - from the lungs of Korean striped field mice (Apodemlls agrarills) [Lee et aI., 1978]. Outside Scandinavia and east Asia the first serologically confrrmed human cases of Hantaanlike virus infection were described in Belgium in 1983 [Desmyter et aI., 1983]. Subsequently, it has indeed become clear that all the above mentioned diseases are caused by closely related viruses [Gajdusek, 1982; Lee, 1989] which have now been included in the genus Hantavirus of the Bunyaviridae family. In 1983, the rodentborne viruses serologically related to Hantaan virus, all causing similar clinical symptoms, were labelled under the generic term haemorrhagic fever with renal syndrome (HFRS) [WHO, 1983].

Hantavirus infections in The Netherlands: epidemiology and disease. (Article)

1995-01-01T00:00:00Z

A serological survey for the prevalence of hantavirus infections in The Netherlands was carried out on > 10,000 sera, from selected human populations, and different feral and domestic animal species. Hantavirus-specific antibodies were found in about 1% of patients suspected of acute leptospirosis, 10% of patients with acute nephropathia, and in less than 0.1% haemodialysis and renal transplant patients. Among individuals with a suspected occupational risk, 6% of animal trappers, 4% of forestry workers, 2% of laboratory workers and 0.4% of farmers were seropositive. The majority of the seropositive individuals lived in rural and forested areas. The main animal reservoir of the infection was shown to be the red bank vole (Clethrionomys glareolus). Epidemiological, clinical and laboratory findings seen in serologically confirmed human cases were similar to those associated with nephropathia epidemica.

Epidemiology and laboratory diagnosis of Hantavirus (HTV) infections. (Article)

1995-01-01T00:00:00Z

Hantavirus (HTV) is recently discovered "hemorrhagic fever virus" belonging to the Bunyaviridae family, which is spread throughout the world by wild rodents and/or laboratory rats. During an epidemic in the Belgian-French Ardennes in 1993, more than 200 acute cases were recorded of the milder European form of HTV-illness, otherwise known as Nephropathia epidemica (NE). This variant may be recognized by the sudden onset of fever, acute renal failure, thrombocytopenia and sometimes by ophthalmologic complications. The symptomatology is rather aspecific and diagnosis can only be confirmed by serologic tests, of which the best option nowadays seems to be: screening by IgG EIA, followed by IgM confirmation with a mu-capture EIA test. Some of the tests described allow an evaluation of the causative serotype or even the moment of infection. Next to the "classic" serologic assays for detection of specific viral antibodies, we describe briefly our own experience with newer tests such as "high density particle agglutination" and "line immuno assay". Polymerase chain reaction for viral RNA genome typing and immunohistochemical colouring of the viral antigen in tissues seem to offer promising alternatives for the immediate future.

A macaque model for hantavirus infection. (Article)

1995-01-01T00:00:00Z

Cynomolgus macaques (Macaca fascicularis) were experimentally infected with Puumala virus (strain Hallnas), which causes nephropathia epidemica in humans in western Europe. During the first week after intratracheal inoculation, the monkeys exhibited signs of lethargy followed by mild proteinuria and microhematuria. Histopathologic changes during the first 7 weeks after infection were largely confined to abnormalities in medullary tubular cells of the kidneys, which coincided with the demonstration of viral antigen and viral RNA. The development of different classes of virus-specific plasma antibodies to the respective viral antigens were similar to those observed in humans with nephropathia epidemica. This first description of a nonhuman primate model for hantavirus infection shows that the cynomolgus macaque provides a suitable model with which to study the pathogenesis of Puumala virus infections and to evaluate new diagnostic methods, immunization strategies, and therapies.

Risk of infections transmitted by arthropods and rodents in forestry workers. (Article)

1994-06-01T00:00:00Z

One hundred and fifty-one forestry workers and 151 matched office clerks were compared as to the presence of antibodies against Borelia burgdorferi, tick-borne encephalitis virus, Puumalavirus and lymphocytic choriomeningitis virus. Their occupational risks of being infected by Borrelia was fourfold and significant, by Puumalavirus and lymphocytic choriomeningitis virus was increased but not significant. No seropositivity has been established against tick-borne encephalitis virus.

An enzyme-linked immunosorbent assay for the detection of mouse polyomavirus-specific antibodies in laboratory mice. (Article)

1994-01-01T00:00:00Z

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection and quantification of IgM and IgG serum antibodies to mouse polyomavirus (MPV). To evaluate the potential of this ELISA for the screening of laboratory rodents, serum samples from specific pathogen free (SPF) BALB/c RIVM mice, collected after experimental intraperitoneal infection with MPV, were tested by this assay. The results were compared with those obtained from the same sera in an immunofluorescence assay (IFA) and a haemagglutination inhibition assay (HIA). The ELISA proved to be the most sensitive of the 3 assays, allowing the detection of seropositive animals within 7 days post-infection and giving antibody titres that were about 4 to 8 times higher than those found in the IFA and HIA respectively. More than 5000 serum samples from non-infected specific pathogen free laboratory mice and 90 from 10 SPF N:NIH/RIVM mice experimentally infected with K-papovavirus, were negative in this assay, thus confirming the specificity of the ELISA.

Guillain-Barré syndrome associated with hantavirus infection. (Article)

1994-01-01T00:00:00Z

Letter

Class and subclass distribution of hantavirus-specific serum antibodies at different times after the onset of nephropathia epidemica. (Article)

1994-01-01T00:00:00Z

Sera from Dutch and Belgium individuals who suffered from nephropathia epidemica (NE), a mild form of haemorrhagic fever with renal syndrome (HFRS), were tested for the distribution of classes and subclasses of Hantavirus (HV)-specific antibodies at different times after the onset of the disease, with class- and subclass-specific Ig capture enzyme-linked immunosorbent assays (ELISAs). In the acute, early convalescent, and convalescent phases, predominantly specific IgA, IgM, and IgG3 antibodies were detected. Specific IgG2 antibodies were only detected at low levels in the early convalescent and convalescent phases. In the late convalescent phase specific IgG1 and IgG3 antibodies were found, whereas in the late postconvalescent phase only specific IgG1 antibodies proved to be present. Specific IgG4 antibodies were not detected in any of the respective phases. These data show that the simultaneous determination of classes and subclasses of HV specific serum antibodies allows the estimation of the time elapsed after the onset of NE.

Structural and functional studies on a unique linear neutralizing antigenic site (G5) of the rabies virus glycoprotein. (Article)

1993-01-01T00:00:00Z

The core of a unique linear neutralization epitope (G5) on the glycoprotein of rabies virus, recognized by a virus-neutralizing mouse monoclonal antibody (MAb 6-15C4), was determined by Pepscan analysis. The G5 epitope was defined as an octapeptide (LHDFRSDE). The contribution of the individual amino acids of the G5 epitope to the binding of MAb 6-15C4 was analysed with a set of synthetic peptides in which the individual amino acids had been replaced in turn by each of the other 19 naturally occurring amino acids. Five amino acids of the octapeptide proved to be essential for the binding of MAb 6-15C4. The conservation of the G5 epitope within the glycoprotein of the different rabies virus strains sequenced to date proved to be absolute at the amino acid level. Studies concerning the immunodominance of the G5 epitope were carried out by determining the presence of G5 epitope-specific serum antibodies in vaccinated human and mice, and by determining the frequency of G5 epitope-specific B lymphocytes in the blood of vaccinated humans. These studies indicated that antibodies to the G5 epitope constitute a minor population of the rabies virus-specific serum antibodies induced by rabies vaccination.

Haemorrhagic fever with renal syndrome. (Article)

1993-01-01T00:00:00Z

Letter

Molecular and serological studies on the recent seal virus epizootics in Europe and Siberia. (Article)

1992-05-06T00:00:00Z

The virus epizootics which occurred in seals in both Europe and Siberia during 1987/1988 were caused by two different morbilliviruses, referred to as phocid distemper virus (PDV) 1 and 2, respectively. Molecular and serological studies have shown that the European virus is quite distinct from canine distemper virus (CDV), its closest relative in the morbillivirus group. Analysis of tissues obtained from infected seals from a wide geographical distribution over Northern Europe showed that the infectious agent (PDV 1) was identical in all cases. Nucleotide sequence analysis of one of the virus genes suggested that this virus has evolved away from CDV over a long time period and is most probably an enzootic virus of marine mammals. In contrast, the virus (PDV 2) which caused the deaths of many Siberian seals was indistinguishable, both serologically and at the molecular level, from CDV and must have originated from a land source.

The use of enzyme-linked immunosorbent assay systems for the serology and antigen detection in parvovirus, coronavirus and rotavirus infections in dogs in The Netherlands. (Article)

1991-01-29T00:00:00Z

Complex trapping blocking (CTB) enzyme-linked immunosorbent assays (ELISAs) and indirect ELISAs for the detection of antibodies to canine parvovirus (CPV), canine coronavirus (CCV) and rotavirus in sera of dogs were established. Double antibody sandwich ELISAs for the detection of CPV-, CCV- and rotavirus antigens in fecal samples were also developed. Both the serological and antigen-detection ELISAs were used to screen samples from dogs in The Netherlands, with or without a history of acute diarrhea. It was shown that the results of the respective serological ELISAs correlated well and that CPV was the major cause of virus-induced acute diarrhea in dogs in The Netherlands.

Identification of Hantavirus serotypes by testing of post-infection sera in immunofluorescence and enzyme-linked immunosorbent assays. (Article)

1991-01-01T00:00:00Z

Serum samples were collected from 27 individuals who had been infected with a member of the genus Hantavirus in the Netherlands or Belgium during the last 15 years. These samples were tested in an immunofluorescence assay (IFA) and two enzyme-linked immunosorbent assay (ELISA) systems, using different virus strains that represented each of the four recently proposed serotypes of this genus. The serum samples from 11 individuals who had been infected through contacts with laboratory rats showed the highest reactivities with Hantaan virus (serotype I) and SR-11 (serotype II) in the IFA and ELISA systems. The samples of 16 individuals who had probably been infected through contacts with wild rodents showed the highest reactivities with Hallnas virus (serotype III) in the IFA. All except two of these also showed the highest reactivity with Hallnas virus in the two different ELISA systems.

Different hantavirus serotypes in western Europe. (Article)

1991-01-01T00:00:00Z

Hantavirusinfecties in Nederland. (Article)

1991-01-01T00:00:00Z

Mass mortality in seals caused by a newly discovered morbillivirus. (Article)

1990-09-24T00:00:00Z

During a recent disease outbreak among harbour seals (Phoca vitulina) in the North and Baltic seas, more than 17,000 animals have died. The clinical symptoms and pathological findings were similar to those of distemper in dogs. Based on a seroepizootiological study, using a canine distemper virus (CDV) neutralization assay, it was shown that CDV or a closely related morbillivirus (phocid distemper virus-PDV) was the primary cause of the disease. The virus was isolated in cell culture from the organs of dead seals and characterized as a morbillivirus by serology (immunofluorescence neutralization and enzyme-linked immunosorbent assays) and by negative contrast electron microscopy. Experimental infection of SPF dogs resulted in the development of mild clinical signs of distemper and CDV-neutralizing antibodies. The disease was reproduced in seals by experimental inoculation of organ material from animals that had died during the outbreak. However, seals that had been vaccinated with experimental inactivated CDV vaccines were protected against this challenge. This fulfilled the last of Koch's postulates, confirming that the morbillivirus isolated from the seal organs, was the primary cause of the disease outbreak. The recent demonstration of the presence of a similar virus in Lake Baikal seals (Phoca sibirica), which infected these Siberian seals 1 year before the northwestern European seals were infected, raises new questions about the origin of this infectious disease in pinnipeds.

Evaluation of enzyme-linked immunosorbent assays based on monoclonal antibodies for the serology and antigen detection in canine parvovirus infections. (Article)

1990-01-01T00:00:00Z

An enzyme-linked immunosorbent assay (ELISA) system was developed for the detection of canine parvovirus (CPV) or CPV antigen in dog faeces and two other ELISA systems were developed for the detection of CPV-specific antibodies in dog sera. The ELISA's were based on the use of CPV-specific mouse monoclonal antibodies, which recognise different epitopes of the haemagglutinin of CPV and which also neutralise the virus. A double antibody sandwich (DAS) ELISA for the detection of CPV in dog faeces was compared with the haemagglutination (HA) test. The DAS-ELISA proved to be more specific, sensitive and easier to perform than the HA assay. An indirect ELISA and a competitive ELISA for the detection of CPV-specific antibodies in dog sera were compared with the haemagglutination inhibition (HI) test. Both ELISA systems proved to be specific and easy-to-use methods for the detection of CPV-specific antibodies. The indirect ELISA, specially, proved to be more sensitive than the HI test. The higher sensitivity and specificity of the ELISA's as compared to HA and HI tests, and their ease of use, make them suitable for routine use in the serology and diagnosis of CPV infections.

Hantavirus nephropathy in The Netherlands. (Letter To Editor)

1989-08-05T00:00:00Z

Comparison of an enzyme-linked immunosorbent assay, an immunofluorescence assay and a hemagglutination inhibition assay for detection of antibodies to K-papovavirus in mice. (Article)

1989-01-01T00:00:00Z

The sensitivity of a newly developed enzyme-linked immunosorbent assay (ELISA) for detection of antibody to K virus was compared with the sensitivities of an immunofluorescence assay (IFA) and a hemagglutination inhibition assay (HIA). Specific pathogen-free BALB/c RIVM mice, 5 weeks old, were inoculated intraperitoneally with a mouse organ suspension containing 10(4.5) TCID50 of K virus per dose. Control animals were inoculated with a control mouse organ suspension. No clinical signs were observed during the 7 weeks they were followed for the development of serum antibody. The ELISA proved to be the most sensitive of the three assays and demonstrated K virus-specific antibodies as early as 3 days after infection.

Distemper virus in Baikal seals (Letter To Editor)

1989-01-01T00:00:00Z

Comparison of immunofluorescence and enzyme-linked immunosorbent assays for the serology of hantavirus infections. (Article)

1989-01-01T00:00:00Z

Three enzyme-linked immunosorbent assay (ELISA) systems based upon different principles were developed for the serology of Hantaan virus infections and compared with an indirect immunofluorescence assay (IFA). The indirect IFA was carried out with gamma-irradiated Hantaan virus-infected and uninfected Vero E6 cells fixed with ethanol (-70 degrees C) or acetone (20 degrees C) on drop slides and a FITC-coupled sheep anti-human Ig preparation. Atypical staining in the IFA was avoided by using ethanol (-70 degrees C) instead of acetone (20 degrees C) fixation. In the first ELISA ('cell-assay'), Hantaan virus-infected or uninfected Vero E6 cells were used as antigens, which after gamma-irradiation were seeded into microtiter ELISA strips. Serial dilutions of human sera were incubated and specific antibodies were demonstrated with a horseradish peroxidase (HRPO)-conjugated sheep anti-human Ig preparation. In the second ELISA ('competition-assay') an affinity-purified human Ig preparation was used as a capture antibody for Hantaan virus antigen. After incubation of serial dilutions of human sera with this coat, the reactivity of the affinity purified anti-Hantaan virus Ig coupled to HRPO was determined. In the third ELISA ('complex trapping blocking [CTB]-assay') the same capture antibody was used to react with a mixture of the antigen and serial dilutions of human sera. The reactivity with the same HRPO conjugate was then determined. The results obtained in the respective assay systems with sera from people at risk or suspected of Hantaan virus infection coincided well. The CTB-ELISA proved to be faster and more sensitive than both the other ELISA systems, without giving more non-specific reactions: it detected almost all the IFA positive samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Morbillivirus infections in European seals before 1988. (Article)

1989-01-01T00:00:00Z

Wederom een geval van hantavirusinfectie in Nederland. (Miscellaneous)

1989-01-01T00:00:00Z

In a serological survey among Dutch patients suspected of leptospirosis, using a recently developed enzyme-linked immunosorbent assay, a patient was traced with a high antibody titre to Hantaan virus. No anti-leptospira antibodies were detected in this 27-year-old man. Shortly before he had been admitted to the hospital with progressive dyspnoea and coughing, accompanied with high fever. An interstitial pneumonia was diagnosed. He subsequently developed a progressive renal failure with proteinuria and polyuria. Later a liver failure accompanied with thrombocytopenia, anaemia and coagulation disturbances occurred. Before an aetiological diagnosis was made, the patient was treated with erythromycin. The patient eventually recovered completely. Based on the clinical symptoms and the positive serology, it was concluded that the disease diagnosed had probably been caused by a Hantaan virus infection. The diagnostic value of Hantaan virus serology in patients with similar symptoms is stressed.

Vaccination of harbour seals (Phoca vitulina) against phocid distemper with two different inactivated canine distemper virus (CDV) vaccines. (Article)

1989-01-01T00:00:00Z

Two inactivated canine distemper virus (CDV) vaccines--an adjuvanted whole inactivated virus and a subunit ISCOM preparation--were tested for their ability to induce protective immunity in harbour seals (Phoca vitulina) against phocid distemper, a disease that recently killed greater than 17,000 harbour seals in the North and Baltic seas, and was shown to be caused by infection with a newly discovered morbillivirus, which is antigenically closely related to CDV. Four CDV seronegative harbour seals were vaccinated three times with the whole-virus vaccine, two with the ISCOM subunit vaccine and two were sham-vaccinated with an antigen-free preparation. Ten days after the last vaccination, when all six vaccinated animals had developed CDV neutralizing antibody titres ranging from 300 to 3000, all eight animals were challenged by the oculonasal and the peritoneal routes, with an organ suspension from dead seals. None of the six vaccinated animals developed clinical signs. The two sham-vaccinated seals died on days 14 and 18, respectively, after having shown a body temperature rise, respiratory symptoms and weight loss. In organs from both dead animals morbillivirus antigen was demonstrated with an enzyme-linked immunosorbent assay and an immunofluorescence assay. One of these two animals had developed a low titre of CDV-specific antibodies just before death. These data clearly indicate that seals can be protected from fatal challenge with the phocid distemper virus (PDV), by vaccination with certain inactivated CDV vaccines. They also reconfirm that infection with PDV should be considered the primary cause of the recent epizootic in seals.

Different morbilliviruses in European and Siberian seals. (Article)

1989-01-01T00:00:00Z

Canine distemper virus in seals (Letter To Editor)

1988-01-01T00:00:00Z

Een uitbraak van 'hondeziekte' bij zeehonden (2). (Article)

1988-01-01T00:00:00Z

Serological findings which had showed that the primary cause of the recent outbreak of serious disease of seals in the seas of North-Western Europe, is infection with canine distemper virus, were confirmed by in vivo and in vitro isolation of the virus from seals which had died at different locations during the outbreak. The virus which proved to be pathogenic for dogs, was characterised as canine distemper virus on the basis of immunofluorescence, virus neutralisation and electron microscopical studies.

Purification of infectious canine parvovirus from cell culture by affinity chromatography with monoclonal antibodies. (Article)

1987-01-01T00:00:00Z

Immuno affinity chromatography with virus neutralizing monoclonal antibodies, directed to the haemagglutinating protein of canine parvovirus (CPV) was used to purify and concentrate CPV from infected cell culture. The procedure was monitored by testing the respective fractions in an infectivity titration system, in an ELISA, in a haemagglutination assay and by negative contrast electron microscopy to quantify CPV or CPV antigen. The degree of purification was further estimated by testing the fractions for total protein content in a colorimetric method, for bovine serum albumin content in an ELISA and by SDS-PAGE. Over 99% of the contaminating proteins proved to be removed, and 20% or 70-90% of infectious CPV or CPV antigen, respectively, was recovered.

Selective inhibitory effects of (S)-9-(3-hydroxy-2-phosphonyl-methoxypropyl)adenine and 1-(2'-deoxy-2'-fluoro-ß-D-arabinofuranosyl)-5-iodouracil on seal herpesvirus (Phocid herpesvirus 1) infection in vitro. (Article)

1987-01-01T00:00:00Z

From a selection of 25 antiviral compounds with specific anti-herpes activity or broad-spectrum antiviral properties, two compounds, namely (S)-9-(3-hydroxy-2-phosphonyl-methoxypropyl)adenine and 1-(2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl)-5-iodouracil, appeared particularly effective in inhibiting the cytopathogenicity of seal herpesvirus (phocid herpesvirus 1).

The isolation and partial characterization of a highly pathogenic herpesvirus from the harbor seal (Phoca vitulina). (Article)

1985-01-01T00:00:00Z

This report describes the first isolation and partial characterization of a herpesvirus from the harbor seal (Phoca vitulina). The virus was isolated during a disease outbreak in a group of young seals nursed in a seal orphanage in The Netherlands. Almost half of the seals died with symptoms of acute pneumonia and focal hepatitis and the virus was isolated of organs of most of the dead animals. Seven out of ten seals of which paired serum samples were obtained showed seroconversion in a virus neutralization test during this outbreak. The virus was tentatively characterized as a herpesvirus (seal herpesvirus: SeHV or phocid herpesvirus 1) on the basis of its characteristic morphology in electron microscopy, buoyant density in sucrose, sensitivity to ether and heat treatment and its antigenic relationship with other probable members of the Alphaherpesvirinae subfamily. The virus caused cytopathic changes within 24 hours after inoculation in seal kidney cells, consisting of a focal rounding of cells and syncytium formation. No cytopathic changes were observed in the cells of nine other mammalian species tested.