Evaluation of seven immunoassays for detection of rotavirus in pediatric stool samples

Evaluation of the diagnostic performance of EpiTuub® Fecal Rotavirus Antigen Rapid Test Kit in Amhara National Regional State, Ethiopia: A multi-center cross-sectional study

Rotavirus is the leading cause of morbidity and mortality due to acute gastroenteritis among children under five years globally. Early diagnosis of rotavirus infection minimizes its spread and helps to determine the appropriate management of diarrhea. The aim of this study was to evaluate the performance of EpiTuub® Fecal Rotavirus Antigen Rapid Test Kit for the diagnosis of rotavirus infection among diarrheic children under five years in Ethiopian healthcare settings. A total of 537 children with diarrhea were enrolled from three referral hospitals in Amhara National Regional State, Ethiopia. The samples were tested using one-step RT-PCR and EpiTuub® Fecal Rotavirus Antigen Rapid Test Kit (KTR-917, Epitope Diagnostics, San Diego USA) in parallel. Diagnostic performance of the rapid test kit was evaluated using the one-step RT-PCR as a gold standard. The sensitivity, specificity, and predictive values of the rapid test kit were determined. Moreover, the agreement of the rapid test kit with one step RT-PCR was determined by kappa statistics and receiver operators' curve (ROC) analysis was done to assess the overall diagnostic accuracy of the rapid test kit. Fecal Rotavirus Antigen Rapid Test Kit has shown a sensitivity of 75.5% and specificity of 98.2%. The kit was also found to have 89.9% and 95.0% positive and negative predictive values, respectively. The Fecal Rotavirus Antigen Rapid Test Kit has shown a substantial agreement (78.7%, p = 0.0001) with one-step RT-PCR. The overall accuracy of the Fecal Rotavirus Antigen Rapid Test Kit was excellent with the area under the ROC curve of 86.9% (95% CI = 81.6, 92.1%) (p = .0001). Thus, Fecal Rotavirus Antigen Rapid Test is a sensitive, specific, user-friendly, rapid, and equipment-free option to be used at points of care in Ethiopian health care settings where resource is limited precluding the use of one step RT-PCR. Furthermore, the kit could be used in the evaluation and monitoring of rotavirus vaccine effectiveness in the aforementioned settings.

The importance of stool tests in diagnosis and follow-up of gastrointestinal disorders in children

Stool is not just a simple waste material. Some stool tests can be easily used in primary care in the differential diagnosis of disorders such as gastrointestinal infections, malabsorption syndromes, and inflammatory bowel diseases. Stool tests can prevent unnecessary laboratory investigations. Stool analyses include microscopic examination, chemical, immunologic, and microbiologic tests. Stool samples can be examined for leukocytes, occult blood, fat, sugars (reducing substances), pH, pancreatic enzymes, alpha-1 antitrypsin, calprotectin, and infectious causes (bacteria, viruses, and parasites). Stool should also be macroscopically checked in terms of color, consistency, quantity, shape, odor, and mucus.

Development of a new enzyme immunoassay for improved detection of rotavirus in fecal specimens of vaccinated infants

BACKGROUND

Group A rotavirus is the most common cause of acute diarrhea in young children worldwide. A simple and rapid enzyme immunoassay (EIA) has been commonly used to detect rotavirus infection and evaluate rotavirus vaccines. Currently licensed commercial EIA kits have low sensitivity. A more sensitive detection of rotavirus can improve rotavirus diagnostics and vaccine efficacy studies.

OBJECTIVE

A biotin-avidin based sandwich EIA was developed and compared with commercial EIA kits for improved detection of viral shedding in fecal samples from infants who received human rotavirus vaccine Rotarix in Mexico.

STUDY DESIGN

A monoclonal antibody (mAb: 1D4) specific to human rotavirus group antigen VP6 was prepared and used to develop a biotin-avidin based sandwich EIA. This EIA was employed to test 128 fecal samples from vaccinated infants, in comparison with two commercial EIA kits using RT-PCR as a reference.

RESULTS

A new biotin-avidin based sandwich EIA showed specific reaction to group A rotaviruses, but not to other enteric viruses. This new EIA had a detection rate of 36.7% for rotavirus antigen shedding in fecal specimens, which was two times higher (16.4%, 18.0%) than those from two commercial EIA kits.

CONCLUSION

The new EIA had specificity and higher sensitivity than commercial kits. This new EIA has the potential to detect rotavirus at lower concentration in clinical specimens and thus should be further evaluated as a more sensitive kit for use in diagnostics and vaccine efficacy and effectiveness studies.

Development of an immunochromatographic strip for the serodiagnosis of Theileria infection in sheep

Background

Theileria uilenbergi and T. luwenshuni are tick-borne protozoan parasites, transmitted by Haemaphysalis qinghaiensis and H. longicornis, respectively. They are the main causative agents of theileriosis in small ruminants in China. The disease has resulted in severe economic losses and hindered the development of sheep and goat husbandry industry in the endemic regions.

Methods

In this study, a colloidal gold-based immunochromatographic strip (ICS) was developed for the detection of T. uilenbergi and/or T. luwenshuni infections. A recombinant T. uilenbergi immunodominant protein (rTuIP) was used as antigen for the ICS. The nitrocellulose membrane was incubated with rTuIP on the test (T) line and anti-rTuIP antiserum on the control (C) line, respectively. The rTuIP conjugated to colloidal gold particles was used as the detection system for visualization of the lines. Then the sample pad, conjugate pad, nitrocellulose membrane and absorbent pad were assembled onto a backing plate in the appropriate order.

Results

The ICS was able to detect antibodies in the sera of animals experimentally infected with T. uilenbergi from 14 to 85 days. It also reacted with the serum from T. luwenshuni infected sheep. However, there was no cross-reactivity with sera from animals infected with Babesia motasi and Anaplasma ovis. Comparison of the ICS with the rTuIP antigen based indirect enzyme-linked immunosorbent assays (ELISA) using test field samples showed good correlations with 93.1 % (81/87) sensitivity and 100 % (40/40) specificity, respectively, with an almost perfect agreement (Kappa = 0.895, P < 0.01).

Conclusion

An immunochromatographic strip test based on a recombinant T. uilenbergi immunodominant protein (rTuIP) was developed. This is a rapid test (approximately 15 min to completion) for the detection of T. uilenbergi and/or T. luwenshuni infection that is easy to perform and; delivers results that are visible to the naked eye.

Development of latex agglutination test with recombinant NcSAG1 for the rapid detection of antibodies to Neospora caninum in cattle

Neospora caninum, an apicomplexan protozoan parasite, is recognized as a major cause of abortion in cattle. Surface antigen 1 of N. caninum (NcSAG1) is an important immunodominant candidate for the development of a diagnostic reagent for neosporosis. The present study describes the development and evaluation of a latex agglutination test (LAT) with recombinant NcSAG1 (rNcSAG1) for the detection of antibodies to N. caninum in cattle. The rNcSAG1 gene was cloned in pET-28a and protein was expressed in Escherichia coli BL21 (DE3). Carboxylated latex particles were coated with rNcSAG1 and the degree of agreement between LAT and a commercial enzyme-linked immunosorbent assay (iscomELISA) was evaluated by using of 164 serum samples. Twenty-two (13.4%) and 23 (14.0%) of samples were positive for antibodies to N. caninum by LAT and ELISA respectively. Eighteen of 23 ELISA-positive samples were positive according to the LAT and a substantial agreement (κ=0.77) was found between the results of LAT and ELISA. The results indicated that the LAT with rNcSAG1 would be a rapid, simple, relatively inexpensive and suitable diagnostic test for detection of specific antibodies in N. caninum infection under field conditions. Improvement in purification of rNcSAG1 can reduce probable false positive reactions and so increase the degree of agreement between the LAT and ELISA.

Rotavirus infection in a tertiary hospital: laboratory diagnosis and impact of immunization on pediatric hospitalization

BACKGROUND AND OBJECTIVES

Rotavirus (RV) is the main etiological agent of diarrhea in childhood; its laboratory diagnosis is crucial to guide the clinical management and prevention of its spread. RV immunization was introduced in Brazilian 6-month-old children in 2006. The present study was aimed to evaluate three methodologies used for human RV detection in stool samples obtained from patients hospitalized due to gastroenteritis in a teaching hospital and report the impact of RV immunization in hospitalization by diarrhea.

METHODS

293 stool samples collected in the 2001-2008 period were analyzed by enzyme immunoassay (EIA), latex agglutination (LA) and polyacrylamide gel electrophoresis (PAGE).

RESULTS

Rotavirus was detected in 34.8% of samples by LA assay, 28.3% of samples by EIA assay and in 25.6% of samples by PAGE assay. Considering the PAGE method as gold standard, the sensitivity, specificity and accuracy of EIA were 94.6%, 94.4% and 94.5%, and to LA were 82.6%, 81.6% and 81.9%, respectively.

CONCLUSION

These results indicate that antigen detection by EIA is a rapid, sensitive and specific method, and could be used in large-scale applications for screening stool samples suspected of RV infection. This study showed decreased incidence of RV infection in hospitalized children prior to the implementation of the national immunization program against RV.

Development and laboratory evaluation of a lateral flow device (LFD) for the serodiagnosis of Theileria annulata infection

Several DNA-based and serological tests have been established for the detection of Theileria annulata infection, including polymerase chain reaction, reverse line blot and loop-mediated isothermal amplification, indirect enzyme-linked immunosorbent assay (ELISA), and competitive ELISA. In this study, we have applied knowledge from the development and application of a recombinant protein-based indirect ELISA and competitive ELISA to establish a rapid test for point-of-care diagnosis of T. annulata infection in the field to be used by the veterinarian. For the development of a lateral flow test, the recombinantly expressed T. annulata surface protein (TaSP) was applied as the test antigen and anti-TaSP antiserum as the control line. TaSP antigen conjugated to colloidal gold particles was used as the detection system for visualization at the test line for the binding of anti-TaSP antibody present in the serum of infected animals. The developed test specifically detected antibodies in the serum of animals experimentally infected with T. annulata and showed no cross-reactivity with serum from animals infected with other tested bovine pathogens (Trypanosoma brucei, Anaplasma marginale, Babesia bigemina, Babesia bovis, and Theileria parva). Testing of field samples was compared to results obtained by other serological tests, resulting in a sensitivity and specificity of 96.3% and 87.5% compared to indirect fluorescence antibody test, 98.7% and 81.8% compared to indirect ELISA, and 100% and 47.6% compared to competitive ELISA. In conclusion, a rapid test for the detection of T. annulata infection (T. annulata lateral flow device, Ta-LFD) has been developed, which is easy to perform, delivers results to be read by the naked eye within 10 min, and is suitable for the detection of infection in field samples.

Development of an immunochromatographic test to detect antibodies against recombinant Em18 for diagnosis of alveolar echinococcosis

An immunochromatographic test (ICT) for the rapid detection of antibodies to Echinococcus multilocularis was developed. The ICT showed a sensitivity of 94% and a specificity of 95.4%. High degrees of agreement were observed between the ICT and an enzyme-linked immunosorbent assay (kappa = 0.93) and between the ICT and immunoblot analysis (kappa = 0.97). It is expected that the ICT developed in this study will be useful for the serodiagnosis of alveolar echinococcosis.

Development of rapid immunochromatographic test with recombinant NcSAG1 for detection of antibodies to Neospora caninum in cattle

An immunochromatographic test (ICT) with recombinant surface antigen 1 of Neospora caninum (NcSAG1) was developed for the rapid detection of antibodies to N. caninum in cattle. The ICT was used to clearly discriminate between immunofluorescent-antibody test (IFAT)-positive bovine sera and IFAT-negative bovine sera. Serum samples collected from cattle in Yanbian, China, were examined by the ICT. Of the 96 serum samples, 23 (24.0%) were positive by the ICT, and 19 (19.8%) samples were positive by a previously developed enzyme-linked immunosorbent assay (ELISA). Eighteen of 19 ELISA-positive samples were positive according to the ICT. A good agreement was found between the results of the ICT and the ELISA. The results presented here suggest that the ICT with recombinant truncated NcSAG1 fused to glutathione S-transferase is a useful and reliable method for the detection of antibodies to N. caninum in cattle.

Viruses causing gastroenteritis

Acute gastroenteritis is one of the most common diseases in humans worldwide. Viruses are recognized as important causes of this disease, particularly in children. Since the Norwalk virus was identified as a cause of gastroenteritis, the number of viral agents associated with diarrheal disease in humans has steadily increased. Rotavirus is the most common cause of severe diarrhea in children under 5 years of age. Astrovirus, calicivirus and enteric adenovirus are also important etiologic agents of acute gastroenteritis. Other viruses, such as toroviruses, coronaviruses, picobirnaviruses and pestiviruses, are increasingly being identified as causative agents of diarrhea. In recent years, the availability of diagnostic tests, mainly immunoassays or molecular biology techniques, has increased our understanding of this group of viruses. The future development of a safe and highly effective vaccine against rotavirus could prevent, at least, cases of severe diarrhea and reduce mortality from this disease.

Clinical manifestations of rotavirus infection in the neonatal intensive care unit

OBJECTIVES

This report describes clinical signs of rotavirus infection (RVI) among neonates admitted to a neonatal intensive care unit (NICU), compares these signs between term and preterm neonates and assesses the seasonal distribution of RVI in the NICU with that of the community.

METHODS

After an initial prevalence study of 28 days, a prospective longitudinal study in the NICU was conducted. During the next 48 months from December 1, 1991 to November 30, 1995, term and preterm NICU patients were evaluated daily for pre-defined deviations in their baseline gastrointestinal status. Fecal specimens of neonates who fulfilled the entry criteria were tested for rotavirus by a monoclonal antibody-based enzyme immunoassay and by immunoelectron microscopy. Demographic and outcome data for these neonates were collected. In addition data assessing RVI in the community were collected during this period.

RESULTS

The prevalence of RVI among NICU patients was 18.4%. Of 194 neonates included in the longitudinal study, 95 had RVI. Neonates with RVI differed from those without RVI with respect to frequent stooling (P = 0.0005), higher percentage of bloody mucoid stools (P = 0.003) and higher percentage of watery stools (P = 0.023). The odds of these three clinical outcomes were approximately 2.5 times higher in neonates with RVI than in neonates without RVI. Among neonates included in the study advanced necrotizing enterocolitis occurred at the same rate (15%) among those with and without RVI. Comparisons between term and preterm neonates with RVI showed that frequent stooling (P = 0.003) and watery stools (P = 0.0001) occurred more often among term neonates, whereas bloody mucoid stools (P = 0.001), abdominal distention (P = 0.03) and intestinal dilatation (P = 0.016) were more common in preterm neonates. The seasonal distribution of RVI in NICU paralleled its distribution in the community.

CONCLUSION

RVI appears prevalent in the NICU setting. An absence of watery stools in a neonate should not preclude consideration of RVI when evaluating gastrointestinal signs among neonates. The clinical spectrum of RVI differs in term and preterm infants.

Evaluation of two enzyme immunoassays for detection of human rotaviruses in fecal specimens

The two assays evaluated in this study (the Ridascreen rotavirus and the Pathfinder rotavirus) exhibited comparable sensitivities (100%) but highly divergent positive predictive values (93.74 and 57.7%, respectively) when compared on 393 specimens. This difference should be considered when using these tests on collectives with an unknown or low prevalence.

Simultaneous approach for nonculture PCR-based identification and serogroup prediction of Neisseria meningitidis

A nonculture PCR-based method to characterize Neisseria meningitidis was used to test 225 clinical specimens. PCR correctly identified and predicted the serogroups of N. meningitidis of culture-proven meningococcal diseases and confirmed this diagnosis in 35% of suspected samples. This approach could be useful when culture fails to isolate N. meningitidis.

Evaluation of the ImmunoCardSTAT! rotavirus assay for detection of group A rotavirus in fecal specimens

Rapid detection of group A rotavirus was performed by using ImmunoCardStat! Rotavirus (ICS-RV) (which uses immunogold-based, horizontal-flow membrane technology), two commercial enzyme immunoassays (Premier Rotaclone and TestPack Rotavirus), and electron microscopy. A total of 249 stool specimens collected from children with gastroenteritis between February and April 1997 were tested. After resolution of 19 of the 22 discordant results by reverse transcription-PCR for group A rotavirus, ICS-RV detected 125 positives while Rotaclone and TestPack detected 127 and 129 positives, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value were 94.0, 100, 100, and 93.4% for ICS-RV; 95.5, 100, 100, and 95.0% for Rotaclone; and 97.0, 96.5, 97.0, and 96.5% for TestPack. ICS-RV was sensitive and specific and was relatively simple to perform and interpret.

The rotavirus genus

Human rotaviruses, discovered nearly 20 years ago, have been proven to be major cause of paediatric diarrhoeal disease morbidity and mortality. The clinical significance of these viruses stimulated basic studies on their biology, molecular and antigenic properties and epidemiology. General features, clinical relevance, epidemiologic pattern and laboratory diagnosis of human rotavirus infections are here reviewed.

Evaluation of an automated immunodiagnostic assay, VIDAS Rotavirus, for detection of rotavirus in fecal specimens

Four hundred sixty-four fecal specimens were tested for rotavirus by three immunoassays, VIDAS Rotavirus (bioMérieux Vitek, Hazelwood, Mo.), Rotaclone (Cambridge Biotech Corporation, Worcester, Mass.), and Pathfinder Rotavirus (Sansfi Diagnostics Pasteur, Chaska, Minn.). Twenty-seven discordant specimens were evaluated by electron microscopy. The sensitivities, specificities, positive predictive values, and negative predictive values were 98, 99.3, 98.7, and 99%, respectively, for VIDAS Rotavirus; 100, 99, 98.1, and 100%, respectively, for Rotaclone; and 100, 92.4, 87.3, and 100%, respectively for Pathfinder Rotavirus.

Detection of viruses in environmental samples: suitability of commercial rotavirus and adenovirus test kits

Commercially marketed kits are now available for rapid viral assay of clinical specimens. This study was conducted to determine the suitability of these kits for use in environmental testing. Eight rotavirus kits and one enteric adenovirus kit were screened for sensitivity using simian rotavirus SA11, human rotavirus Wa, and adenovirus 41. The most sensitive rotavirus kit and the adenovirus kit were selected for further evaluation using virus-seeded and unseeded sewage samples. The selected rotavirus kit proved capable of detecting virus at the 10(1) PFU/ml level. The enteric adenovirus kit was similarly sensitive, detecting virus at the 10(1) TCID50/ml level. Neither kit was adversely affected by the presence of sewage. Kit assay revealed 3 of 30 unseeded sewage samples to be positive for rotavirus. Adenovirus positive samples were not detected among the 30 samples. These results were confirmed using electron microscopy. It was concluded that sensitive commercial kits could provide a reasonable alternative to cell culture for the presumptive testing of environmental samples.

Rotaviral diarrhea

Rotavirus poses a challenge each foaling season to farm managers and veterinarians in intensive horse breeding areas throughout the world. By understanding the epidemiology of the disease as well as characteristics of the virus, veterinarians can make sound recommendations on prevention and control of outbreaks. Even when effective prophylactic products are developed, farm management practices, including quarantine, disinfection, and hygiene, will always need to be in force to prevent any contagious disease outbreak.

Survey of rotavirus infection in a dairy herd: comparison between polyacrylamide gel electrophoresis and two commercial tests

A survey of rotavirus infection in a dairy herd with a history of neonatal diarrhoea was carried out. Faecal samples taken from 15 cows before and after calving as well as faeces taken from their calves daily from birth to two weeks of life were tested for rotavirus by polyacrylamide gel electrophoresis (PAGE) and compared with an ELISA and a latex agglutination commercial test. Rotavirus excretion was not detected in faeces from cows around parturition by any of the three tests. However, all of their calves shed rotaviruses during the observation period. The onset of rotavirus excretion determined by PAGE ranged from day 2 to day 8 of life (day 4.8 +/- 1.8 on average) and lasted for 4 to 7 days (5.3 +/- 1.1 days on average). Chi-square test showed a significant association (P = 0.0001) between the presence of rotavirus and the altered consistency of calves faeces. All the three tests showed similar results (overall agreement 92.5%) but discrepancies were detected mainly at the beginning or at the end of the rotavirus excretion period. Results obtained with both commercial kits closely paralleled each other and parameters other than sensitivity, specificity, diagnostic accuracy or predictive values have to be considered as selection criteria.

Comparison of polyacrylamide gel electrophoresis, an enzyme-linked-immunosorbent assay, and an agglutination test for the direct identification of bovine rotavirus from feces and coelectrophoresis of viral RNAs

The dsRNA concentrated polyacrylamide gel electrophoresis (CPAGE) detected rotavirus directly from 19% of 77 stool specimens from diarrheic calves. A commercial enzyme-linked immunosorbent assay (ELISA) detected 25%, latex agglutination test, 23%, and polyacrylamide gel electrophoresis (PAGE), 19%. Establishing CPAGE as the "standard," the commercial ELISA and the latex agglutination test both had higher sensitivity (84%) than PAGE (79%). However, PAGE produced the highest specificity (100%), followed by agglutination (88%) and ELISA (84%). The commercial ELISA had a slightly higher sensitivity than agglutination, PAGE, and CPAGE, but the ELISA specificity was generally lower. The latex agglutination test had a lower sensitivity than ELISA, but specificity was higher. Agglutination had similar negative predictive values (94%), compared with agglutination and PAGe, but had the lowest positive predictive value (a measure of accuracy) (70%). Agreement with CPAGE was highest for PAGE (94.8%), followed by agglutination (87%) and ELISA (84.4%). The calculated percentages of total disagreement with all other tests indicated that ELISA differed from the other rotavirus detection assays in 10.4% of the cases, agglutination in 7.8%, PAGE in 2.6%, and CPAGE in 1.3%. The 2 PAGE assays allowed the detection of atypical rotaviruses from feces based on the characteristic "super-short" migration pattern of the 11 genomic segments of rotaviruses and of other members of the Reoviridae.

Choice of reference assay for the detection of rotavirus in fecal specimens: electron microscopy versus enzyme immunoassay

Two previously demonstrated sensitive and specific enzyme immunoassays (EIAs) for rotavirus, one using polyclonal and monoclonal antisera (TestPack Rotavirus [TPK]; Abbott Laboratories) and the other using only monoclonal anti-rotavirus antibodies (Rotaclone [RTC]; Cambridge BioScience Corporation), were evaluated as potential reference assays for rotavirus testing in comparison with direct negative-staining electron microscopy (EM), the current laboratory standard. Two hundred and seven stool samples collected consecutively during the winter of 1989 from children with acute diarrhea admitted to a ward for infants from 0 to 2 years of age were tested by the EIAs and by EM. TPK specimens were read visually; RTC results were read spectrophotometrically. Specimens with discordant EIA and EM results were further evaluated by a fluorescent focus assay. Specimens positive by EM and those negative by EM but positive by fluorescent focus assay were considered to be positive for rotavirus. Of the 207 stools tested, 35 (17%) were positive for rotavirus by these criteria. EM had a sensitivity of only 80%. Specificities were 100% for RTC and EM and 89% for TPK. These findings indicate that EM, although very specific, is relatively insensitive compared with a highly sensitive monoclonal antibody-based EIA. An EIA with high sensitivity and specificity, such as RTC, is a more appropriate reference standard for rotavirus testing.

Comparison of three enzyme immunoassays to tissue culture for the diagnosis of rotavirus gastroenteritis in infants and young children

Three enzyme immunoassays (EIAs), Rotazyme II, IDL, and Pathfinder, were evaluated for rotavirus detection in stool and rectal swab specimens from children with symptomatic gastroenteritis and compared with virus isolation in primary African green monkey kidney cells. Of 125 specimens tested, 49 were rotavirus positive by tissue culture isolation; of these 49, 40 were positive by Rotazyme II, 43 were positive by IDL, and 46 were positive by Pathfinder EIAs. As compared with tissue culture isolation, the Rotazyme II, IDL, and Pathfinder EIAs had sensitivities of 82, 88, and 94%, specificities of 90, 99, and 95%, and overall agreements of 86, 94, and 94%, respectively.

Incidence and diagnosis of rotavirus infection in neonates: results of two studies

The present study investigates the incidence of human rotavirus excretion in neonates of two hospitals. From April 1, 1983 to March 31, 1984, rotaviruses were detected with Rotazyme in the feces of 57 (15%) of 383 neonates at the Department of Pediatrics, University of Berne, in a total in 71 (5.2%) of the 1369 stool samples tested. Of the 57 neonates with Rotazyme-positive stool samples, 53 (93%) were asymptomatic. The problems of the specificity of Rotazyme in neonatal feces and the possibility of rapid testing on neonatology wards are discussed. In a prospective study carried out in April 1986 at the "Schweizerische Pflegerinnenschule in Zurich", rotaviruses were detected with genome gel electrophoresis in the feces of 15 (63%) of 24 risk neonates in the premature baby ward and in 36 (46%) of 79 neonates from the infant nursery, in a total in 63 (34%) of the 188 stool samples tested. In this rotavirus outbreak all rotaviruses detected showed the same band pattern, and therefore had an identical electrophorotype. Symptoms and hospital hygiene aspects of this outbreak will be dealt with in subsequent papers.

Detection of rotavirus by hybridization with a nonradioactive synthetic DNA probe and comparison with commercial enzyme immunoassays and silver-stained polyacrylamide gels

Three enzyme-linked immunosorbent assays (ELISAs) (rotavirus enzyme immunoassay [EIA; International Diagnostic Laboratories], Pathfinder [Kallestad Laboratories], and Rotaclone [Cambridge Bioscience, Inc.]) and hybridization of viral RNA with a nonradioactive, synthetic oligonucleotide DNA probe (SNAP; Molecular Biosystems, Inc.) were compared with silver-stained polyacrylamide gel electrophoresis (PAGE) of viral RNA for the detection of rotavirus in fecal specimens. Hybridization was performed following column purification of the viral RNA. Of 286 specimens analyzed by PAGE, SNAP, rotavirus EIA, Pathfinder, and Rotaclone, 88 were positive by PAGE. All 88 specimens were also positive by the other four assays. Nine specimens that were positive by one or more of the assays were positive by blocking ELISAs but were negative by PAGE. If these nine specimens were considered to be true positives, the final sensitivities and specificities were as follows: PAGE, 91 and 100%; SNAP, 94 and 97%; rotavirus EIA, 96 and 97%; Pathfinder, 100 and 94%; and Rotaclone, 96 and 97%, respectively.

Multicentre evaluation of a new commercial latex agglutination test using a monoclonal antibody for rotavirus detection

A new commercial latex-agglutination test using a monoclonal antibody for detection of rotavirus (Slidex Rota-Kit 2) was compared with three other tests (Slidex Rota-Kit, Rotalex, Rotazyme II) using immunoelectron microscopy and a monoclonal enzyme immunoassay as reference tests. Slidex Rota-Kit 2 was more sensitive and specific than the other tests, and would thus appear to be a practical and accurate rotavirus assay for use in routine laboratory work.

Comparison of five enzyme immunoassays, electron microscopy, and latex agglutination for detection of rotavirus in fecal specimens

Five different enzyme immunoassays, electron microscopy, and latex agglutination (Slidex; bioMerieux) were compared for the rapid detection of human rotavirus in fecal specimens. The enzyme immunoassay using rotavirus polyclonal antiserum (Dakopatts) with simple in-house modifications was shown by the use of confirmatory tests to be the most sensitive and specific procedure.