Évaluation de sept réactifs d'immunochromatographie pour détecter les rotavirus humains dans les selles

Infectious diseases

The measurement of biochemical parameters such as blood glucose, blood gases, electrolytes and cardiac markers have particularly benefited from recent advances in POCT. More and more, this form of analysis is now positively impacting the field of infectious diseases. Many microbiological POCT systems tend to be designed as rapid tests. In general, such tests can be carried out in a few simple steps by medical assistants or physicians without laboratory equipment or laboratory experience. It is even possible for the patients themselves to perform a series of such tests.

Diagnostic accuracy of VIKIA® Rota-Adeno and Premier™ Rotaclone® tests for the detection of rotavirus in Niger

Objective

We conducted a parallel evaluation of the diagnostic accuracy of VIKIA® Rota-Adeno, a rapid diagnostic test (RDT) and Premier™ Rotaclone® an enzyme immunoassay (EIA) using reverse transcription polymerase chain reaction (RT-PCR) as the reference standard. The study was part of a rotavirus surveillance project in Niger.

Results

The sensitivity of both tests was 80.7%. After exclusion of one indeterminate result by visual reading, the specificity of the Premier™ Rotaclone® was 100% by visual or optical density readings and that of VIKIA® Rota-Adeno test was 95.5%. Inter-reader agreement was excellent for both tests (kappa = 1). Our results showed almost similar performance of the EIA and RDT when compared to RT-PCR. Hence, the VIKIA® Rota-Adeno could be a good alternative for use in peripheral health centres where laboratory capacity is limited.

Diagnostic Accuracy of Seven Commercial Assays for Rapid Detection of Group A Rotavirus Antigens

Seven commercial immunochromatographic assays intended for the detection of group A rotavirus antigens in human stool samples were evaluated. These assays showed similar levels of diagnostic accuracy and were suitable for the detection of rotavirus in patients with acute gastroenteritis but missed some asymptomatic rotavirus shedding identified by real-time reverse transcription-PCR.

[Interests and limitations of rapid diagnostic tests for respiratory and gastrointestinal viral diseases]

Les tests de dépistage rapide (TDR) basés sur la technique d’immunochromatographie sont très répandus pour le diagnostic des maladies infectieuses. Dans le cadre des infections respiratoires virales, il s’agit essentiellement de tests pour le diagnostic de la grippe et des infections à virus respiratoire syncytial (VRS). Pour le diagnostic des gastroentérites virales, ce sont des tests de détection des rotavirus, adénovirus, norovirus et astrovirus qui peuvent être utilisés. Les TDR pour les infections à VRS et les gastroentérites sont utilisés essentiellement dans le cadre de la pathologie pédiatrique. Ces tests présentent généralement une spécificité élevée mais une sensibilité modeste par rapport aux techniques moléculaires. Ce sont donc surtout des tests de dépistages et leur négativité ne permet pas d’exclure le diagnostic.

Rotavirus surveillance in urban and rural areas of Niger, April 2010-March 2012

Knowledge of rotavirus epidemiology is necessary to make informed decisions about vaccine introduction and to evaluate vaccine impact. During April 2010–March 2012, rotavirus surveillance was conducted among 9,745 children <5 years of age in 14 hospitals/health centers in Niger, where rotavirus vaccine has not been introduced. Study participants had acute watery diarrhea and moderate to severe dehydration, and 20% of the children were enrolled in a nutrition program. Of the 9,745 children, 30.6% were rotavirus positive. Genotyping of a subset of positive samples showed a variety of genotypes during the first year, although G2P[4] predominated. G12 genotypes, including G12P[8], which has emerged as a predominant strain in western Africa, represented >80% of isolates during the second year. Hospitalization and death rates and severe dehydration among rotavirus case-patients did not differ during the 2 years. The emergence of G12P[8] warrants close attention to the characteristics of associated epidemics and possible prevention measures.

Evaluation of 4 immunochromatographic tests for rapid detection of norovirus in faecal samples

BACKGROUND

The rapid detection of noroviruses is essential to implement measures to reduce the rapid spread of gastroenteritis infections they cause, notably in institutions.

OBJECTIVES

To evaluate 4 rapid immunochromatographic tests: RIDA(®)QUICK Norovirus, ImmunoCardSTAT!(®) Norovirus, NOROTOP(®) and SD BIOLINE NOROVIRUS by determining their sensitivity and specificity on a large panel of samples representing 11 genotypes of norovirus genogroup I and 14 of genogroup II, and their cross-reactivity with other enteric viruses.

STUDY DESIGN

Thawed stool samples containing norovirus genogroup I or II or other enteric viruses, and negative samples, were tested by the 4 assays and compared to the reference standard RT-PCR. Fresh stool samples were also tested by RIDA(®)QUICK.

RESULTS

The sensitivity of RIDA(®)QUICK, ImmunoCardSTAT!(®), NOROTOP(®) and SD BIOLINE for the detection of norovirus genogroup I on thawed samples was 17%, 26%, 52% and 23%, respectively. For genogroup II, the sensitivity was 64%, 39%, 50% and 54%, respectively. For GII.4, the main circulating genotype, the sensitivity was 78%, 59%, 61% and 67%, respectively. For all tests, the specificity was 100% and no cross-reactivity with other enteric viruses was observed. The sensitivity of RIDA(®)QUICK on fresh stool samples positive for GII.4 was 71%.

CONCLUSIONS

Knowing that most gastroenteritis cases are due to GII.4, the immunochromatographic tests may be useful for preliminary screening, notably in outbreaks. However, negative samples need to be tested using RT-PCR methods.

Evaluation of an immunochromatography method for rapid detection of noroviruses in clinical specimens in Thailand

Norovirus (NoV) is a causative agent of gastroenteritis in children and adults worldwide. Although reverse transcription-polymerase chain reaction (RT-PCR) has been accepted as the standard method for diagnosis of NoV infection, it requires well-trained personnel and sophisticated equipments. Performance of a commercial immunochromatography (IC) test for rapid detection of NoV was evaluated with fecal specimens collected from children admitted to a hospital with acute gastroenteritis during 2005-2007 in Chiang Mai, Thailand. A total of 463 fecal specimens were tested for the presence of NoV by a commercial immunochromatography kit (IP-NoV) and by RT-PCR. Sensitivity, specificity, and agreement of immunochromatography as compared to RT-PCR were 74.2%, 99.5%, and 96.1%, respectively. Based on the NoV genotypes determined by phylogenetic analysis, immunochromatography detected NoV GII/3, GII/4, GII/6, GII/13, GII/15, and GII/16 genotypes. The findings indicate that the immunochromatography kit could be used for a direct detection of NoV GII in clinical specimens and covering a wide range of NoV genotypes circulating in Thailand.

Development and application of lateral flow test strip technology for detection of infectious agents and chemical contaminants: a review

Recent progress in the laboratory has been a result of improvements in rapid analytical techniques. An update of the applications of lateral flow tests (also called immunochromatographic assay or test strip) is presented in this review manuscript. We emphasized the description of this technology in the detection of a variety of biological agents and chemical contaminants (e.g. veterinary drugs, toxins and pesticides). It includes outstanding data, such as sample treatment, sensitivity, specificity, accuracy and reproducibility. Lateral flow tests provide advantages in simplicity and rapidity when compared to the conventional detection methods.

Norovirus in a Dutch tertiary care hospital (2002-2007): frequent nosocomial transmission and dominance of GIIb strains in young children

We report a retrospective analysis of norovirus (NoV) infections occurring in patients of a tertiary care hospital during five winter seasons (2002/03 to 2006/07). Data were compared with national surveillance data and with corresponding data for rotavirus. Between July 2002 and June 2007, faecal specimens from 221 (9.0%) of 2458 hospital patients with diarrhoea tested positive for NoV. The incidence in children varied from 2.52 per 1000 admissions in 2004/05 (when testing began to be performed routinely) to 11.9 per 1000 admissions in 2006/07, while the incidence in adults remained stable (mean: 1.49 per 1000 admissions). Two genotypes predominated during the study period: GIIb strains occurred mainly in children below the age of two-and-a-half years [odds ratio (OR): 14.7; P<0.0001] whereas GII.4 strains affected all age groups. Compared with rotavirus infections, NoV infections in children were more often hospital-acquired (59% vs 39%, OR: 2.29; P<0.01). Among these cases we identified 22 clusters of NoV infection among inpatients. Twelve of 53 patients from whom follow-up samples were available demonstrated long-term virus shedding. We report a dynamic pattern of sporadic NoV infections in large hospitals, with frequent nosocomial transmission and with the predominance of GIIb-related strains in children. Effective prevention strategies are required to reduce the impact of sporadic NoV infection in vulnerable patients.

[Sensitivity and specificity of the VIKIA Rota-Adeno immuno-chromatographic test (bioMérieux) and the ELISA IDEIA Rotavirus kit (Dako) compared to genotyping]

The performances of two diagnostic tests for rotavirus infection in stool samples were evaluated during a prospective study in children of less than 36 months in child-care centers of Lyon from November 2004 to May 2005. The VIKIA Rota-Adeno immuno-chromatographic test (bioMérieux) and the ELISA IDEIA Rotavirus kit (Dako) were compared with a referral method, the genotyping. Fifty-seven stool samples were collected and analyzed by RT-PCR. The virus genome was detected in 29 samples. The most frequent genotypic combinations were G9P[8] with a prevalence of 75.9%. Sensitivity and specificity of the VIKIA Rota-Adeno test and the ELISA IDEIA Rotavirus kit were strictly comparable and very good: 96.6% (83.0; 99.9) and 96.4% (81.6; 99.9), respectively. The immuno-chromatographic technique were in concordance with the ELISA tests in 93.6% of cases. Thus, the VIKIA Rota-Adeno test is a good alternative for the occasional analysis of stool samples in ambulatory practice.

[Prospective epidemiological study of rotavirus gastroenteritis in Europe (REVEAL study). Results in the French area of the study]

PRIMARY OBJECTIVE

To estimate the incidence of acute gastroenteritis (AGE) and rotavirus acute gastroenteritis (RVAGE) in children less than 5 years of age seeking medical care in primary care, emergency department, and hospital settings.

SECONDARY OBJECTIVES

To compare the clinical profile of RVAGE and non-RVAGE and to describe the distribution of RV serotypes among RVAGE cases.

METHODS

A prospective primary care, emergency ward and hospital-based observational study was conducted during 1 year in a selected city of France with 250,000 inhabitants. Children less than 5 years of age presenting with symptoms of AGE were included. Rotavirus was identified using an Elisa test in stools.

RESULTS

The estimated annual incidence of RVAGE was 1.56% for AGE and 0.87% for RVAGE in hospital, 5.87% for AGE and 2.65% for RVAGE in emergency-wards, 7.39% for AGE and 1.45% for RVAGE in primary care. Total incidence was 14.82% for AGE and 4.96% for RVAGE among children less than 5 years of age. RVAGE were more clinically severe than the AGE: dehydration (26.8% vs. 14.7%, p<0.0001), vomiting 84.9% vs. 60.9%, p<0.0001), fever (74.3% vs. 44.4%, p<0.0001), lethargy (84.9% vs. 70.2%, p<0.0001). G9 serotype was the most frequent serotype encountered (54.7%) during the study period followed by G3 serotype (33.6%) and G2 serotype (7.9%).

CONCLUSION

In this study, RVAGE, caused by serotypes G9 and G3, represented about 1/3 of AGE and were more severe than non-RV AGE with twice as high dehydration rate. These results underline the need for continued promotion on the use of oral rehydration fluids and provide some arguments on the benefits of vaccination against rotavirus and also permanent virological monitoring of circulating serotypes.

[Epidemiology and burden of rotavirus diarrhea in day care centers in Lyon, France]

Rotavirus is the main cause of severe, dehydrating diarrhoea in infants and young children. In industrialized countries, pediatric rotavirus gastroenteritis (PRGE) is responsible for high morbidity, particularly among children under 3 years of age attending day care centers (DCCs). The objectives of this study were to estimate the incidence, management and cost of PRGE in DCCs. We also described the nature of group A rotavirus genotypes. This study also compared the performance of different diagnostic techniques. The study was conducted from November 2004 to May 2005. Children aged less than 36 months, attending a participating DCC at least 4 times a week were included in the study. For any episode of acute gastroenteritis (AGE), defined as the occurrence of 3 or more watery or looser than normal stools and/or forceful vomiting within a 24 h period, a fecal specimen was tested by Elisa test IDEIA Rotavirus (Dako) and the immunochromatographic test VIKIA Rota-Adeno (BioMérieux). Sequencing by RT-PCR was performed to identify the rotavirus genotype. Among the 41 DCCs contacted, 18 (43.9%) agreed to participate. Out of 966 children, 547 attended a participating DCC at least 4 times a week and met the inclusion criteria. A total of 302 were included in the study. The clinical diagnosis of AGE was confirmed and validated, by the Elisa test, in 63 fecal specimens, of which 29 (46%) were positive for rotavirus antigen, with a predominance of P[8]G9 (86%). Our results showed good sensitivity and specificity for the VIKIA and Elisa methods when compared to RT-PCR. Among the PRGE cases, 36% were male and the median age was 12.2 months. The first rotavirus case was observed in December 2004 with a peak in January 2005. The incidence of PRGE cases was 2.2 [1.4-3.0] per 100 child-months in children aged less than 36 months of age, increasing to 3.4 per 100 child-months among children aged less than 24 months. Vomiting (P<0.0005) and behavior modification (P<0.001) were significantly more frequent for PRGE cases. A total of 85.7% PRGE cases sought medical attention. In 58.3% of these cases, at least one parent had to miss work for a mean duration of 2.1 days. The total cost of rotavirus cases seeking medical attention (with or without prescribed medication, days off work for parents or additional diaper consumption) was estimated at 275.54 euros/case. The PRGE incidence rate is similar to that estimated in European studies conducted in DDC. These findings confirm that rotavirus transmission occurs not only in DCCs but within the family. This is the first study to give an estimate of the incidence and the cost of rotavirus infection in DCCs in France.

[Frequency and clinical characteristics of rotavirus acute gastroenteritis in children under 5 years of age treated in community practice in France]

OBJECTIVES

The primary objective of this study was to determine the proportion of cases of gastro-enteritis due to rotavirus in children under 5 years of age consulting community physicians. A secondary objective was to compare the clinical characteristics of children with and without rotavirus acute gastro-enteritis (RV AGE).

METHODS

Multicentre, prospective, observational study conducted between December 2005 and May 2006. Each practitioner included 10 consecutive patients presenting with acute gastro-enteritis (AGE).

RESULTS

601 community practitioners, chiefly paediatricians (74.7%), included 5,062 children, 4,383 (86.6%) of whom were evaluable for analysis. The children's median age was 14 months. A rapid detection test (VIKIA((R)) Rota-Adeno - Laboratoires Biomérieux) was performed in 4,178 (95.3%) children and was rotavirus-positive in 43.7% of cases. More than 85% of children presenting with RV AGE were more than 6 months old. The difference between the severity scores of children in whom a rotavirus was detected and those in whom it was not detected was statistically significant (P<0.0001). Rotavirus AGE was significantly different (P<0.0001) from rotavirus-negative AGE in respect of vomiting (78.3% vs 51.0%), fever (76.0 vs 49.4%), weight loss (69.0 vs 43.2%), presence of signs of dehydratation (15.6 vs 3.7%) and behavioural disorders (44.4 vs 36.2%). Hospitalisation was proposed in 5.1% of cases (9.1 vs 1.8%; P<0.0001).

CONCLUSION

In this population of children under 5 years of age treated on an outpatient basis, the rapid detection test revealed the presence of rotavirus in 43.7% of cases. RV AGE appears to be significantly more severe and more often hospitalised.