Amplification of various genes of human group B rotavirus from stool specimens by RT-PCR

Monoclonal antibodies directed against VP7 protein of human group B rotavirus

The aim of this study was to prepare and identify a monoclonal antibody that binds the viral proteins 7 (VP7 protein) of human group B rotavirus (GBRV) and to describe its immunologic characterization. Human group B rotavirus vp7 gene was successfully ligated into pGEX-KG vector and transformed into Escherichia coli TOP10 cells. The glutathione S-transferases (GST)-fusion protein GST-VP7 was induced by Isopropyl β-D-1-thiogalactopyranoside (IPTG) and immediately purified to immunize BALB/c mice. Splenocytes were then prepared from the immunized mouse and fused with SP2/0 myeloma cell line. In the end we obtained one positive hybridoma cell line stably secreting monoclonal antibody against GST-VP7 protein by indirect enzyme-linked immunosorbent assay (ELISA) and limiting dilution. The production of the monoclonal antibody against GBRV will benefit the further study of GBRV's structures and functions and also lay a solid foundation for the research of disease prevention, clinical diagnosis, and treatment.

Prevalence of rotavirus and adenovirus associated with diarrhea among displaced communities in Khartoum, Sudan

BACKGROUND

Diarrheal diseases represent a major worldwide public health problem particularly in developing countries. Each year, at least four million children under five years of age die from diarrhea. Rotavirus, enteric adenovirus and some bacterial species are the most common identified infectious agents responsible for diarrhea in young children worldwide. This study was conducted to determine prevalence of rotavirus and adenovirus associated with diarrhea among displaced communities in Khartoum state, Sudan.

METHODS

A total of seven hundred and ten patients, children and adults, suffering from diarrhea were examined. The clinical history, socio-demographic characteristics, physical examination findings and laboratory investigations were recorded. Stool samples or rectal swabs were collected and tested for rotavirus and adenovirus antigens using the immuno-chromatography test (ICT). Characterization of the identified Rotaviruses, as a major cause of diarrhea, was then made using real time-reverse transcription PCR. To make the study legal, an ethical clearance was obtained from Sudan Ministry of health- Research Ethical Committee. Written consent was taken from adult subjects, and also from children mothers.The participants were informed using simple language about the infection, aim of the research and the benefits of the study.

RESULTS

Out of the 710 patients, viral pathogens were detected in only 99 cases (13.9%). Of the 99 cases of viral diarrhea, 83 (83.8%) were due to rotaviruses while 16 (16.2%) attributed to adenovirus. Of the 83 rotaviruses identified, 42 were characterized by RT-PCR, of these 40 (95.2%) were proved as type A (VP6), and 2 (4.8%) type C (VP7). Type C (VP7) rotavirus was detected in samples collected from children under 5 years only.

CONCLUSIONS

In conclusion, most cases of viral diarrhea are found to be caused by rotavirus especially among children less than five years. Most of the identified rotavirus belonged to type A (VP6).It was also evident that most patients are those who drank untreated water obtained from donkey carts source and who had no access to latrines, and lived in poor environmental conditions would acquire diarrheal infection.

Multiplex real-time PCR assays for the detection of group C rotavirus, astrovirus, and Subgenus F adenovirus in stool specimens

Group C rotavirus (GCRV), astrovirus (AstV), and adenovirus (subgenus F AdenoV) are etiologic agents of acute nonbacterial gastroenteritis, which often represents community outbreaks. For the efficient detection of GCRV, AstV, and subgenus F AdenoV in stool specimens, a multiplex real-time PCR assay was developed to detect these three viruses simultaneously, with high sensitivity and specificity. In total, 8404 clinical specimens were collected between April 2008 and March 2011 and tested for GCRV, AstV, and subgenus F AdenoV by the multiplex real-time PCR, as well as for norovirus (NoV), sapovirus (SaV), and group A rotavirus (GARV) by non-multiplex real-time PCR. Forty-one specimens were positive for GCRV, AstV, or subgenus F AdenoV, including 15 specimens that were also positive for NoV, SaV, or GARV. Multiple viruses were detected simultaneously in 29 out of 4596 (0.63%) specimens infected with at least one virus. The association rates of AstV and subgenus F AdenoV with other viruses were significantly higher than those of NoV, SaV, GARV, or GCRV.

Evidence for Occurrence of Human group B rotavirus in Central India Based on Characterization of NSP2 Gene

Human group B rotavirus (HuGBR) was first described as the causative agent of severe gastroenteritis, affecting millions of people in China during 1982-1983. In spite of serological evidences for the presence of HuGBR in many countries of the world, the virus has only been detected from China, Bangladesh and some parts of India. The present study describes a HuGBR (designated as MP-1 isolate) which was confirmed in an adult patient suffering from gastroenteritis in 2008 in Madhya Pradesh, central India. The RNA electrophoresis in polyacrylamide gel (RNA-PAGE) and NSP2 gene based RT-PCR assays and later sequencing was used to confirm the isolate. The nucleotide and deduced amino acid sequences of this HuGBR (MP-1) isolate were analyzed and their relationship with corresponding gene of other Indian, Bangladeshi and Chinese HuGBR and animal group B rotaviruses (AnGBR) was determined. The isolate showed a typical RNA banding pattern of 4:2:2:3 in RNA-PAGE which was indicative of group B rotaviruses (GBR). The sequence comparison of MP-1 isolate with NSP2 gene revealed that MP-1 isolate had 98.6 and 97.7% nucleotide sequence homology and 93.8% amino acid similarity with Bang373 and CAL-1 strains, respectively. The nucleotide and amino acid sequence similarity of MP-1 isolate with one of the Chinese ADRV (WH-1) strain was 92.8 and 92.5%, respectively. While sequence homology with another Chinese strain ADRV (J19) was considerably lower (45.6 and 48.3%, respectively). The percent identity with AnGBRs (porcine and murine) was also lower at nucleotide and amino acid level (66 to 80%). The phylogenetic analysis suggested that MP-1 isolate is closer to Bangladeshi (Bang373) as compared to Indian strain (CAL-1). Our findings indicated that MP-1 isolate might have originated from a common ancestral HuGBR virus but distinct from AnGBR lineage. Occurrence of GBR in other parts of India warrants further epidemiological and molecular studies to develop effective control strategies for GBR infection in adults as well as children.

Real-time reverse transcription-PCR for detection of rotavirus and adenovirus as causative agents of acute viral gastroenteritis in children

Viral pathogens are the most common cause of gastroenteritis in developed countries. Human rotavirus and adenovirus infections are major causes of acute outbreaks and sporadic cases of gastroenteritis, occurring primarily among children less than 2 years of age. Patient hospitalization is often required, with enormous infection control implications. This work describes the development of real-time PCR assays for the detection of group F adenovirus, rotavirus A, and rotavirus C from stool specimens. Two hundred twenty stool samples from pediatric patients exhibiting symptoms of diarrhea and/or vomiting were examined. PCR results were compared with those of virus detection by electron microscopy and latex agglutination antigen detection. The incorporation of an internal-control RNA that was spiked into individual stool extracts functioned as an internal validation for the reporting of PCR-negative results. Rotavirus C was not detected by real-time PCR in the patient stool samples examined. Real-time reverse transcription-PCR resulted in 175% and 111% increases in the rates of detection of adenovirus F and rotavirus A, respectively, compared with latex agglutination testing. Molecular detection increased the number of stool specimens in which causative agents of gastroenteritis were identified by 155% compared to electron microscopy. Genotyping of a proportion of the rotavirus and adenovirus strains identified only genotype G1 rotavirus and both adenovirus genotypes 40 and 41 in circulation within the patient cohort examined. The results highlight the significance of rapid molecular methods for the routine screening of stool samples in hospital laboratories to provide rapid definitive diagnoses.

RT-PCR based diagnosis revealed importance of human group B rotavirus infection in childhood diarrhoea

BACKGROUND

Human group B rotavirus was first identified as causative agent of a large outbreak of severe gastroenteritis affecting more than 1 million people, predominantly adults in China in 1982-1983. In spite of serological evidences for the presence of group B rotavirus in many countries of the world, the virus has been detected only from China, India and Bangladesh, where most of the cases were from adults.

OBJECTIVES

To ascertain the role of group B rotavirus as an aetiological agent of diarrhoea among children in Kolkata, India.

STUDY DESIGN

An active surveillance was conducted for rotavirus infection in children in a leading referral paediatric hospital and a few samples were also collected from adults of another hospital in Kolkata, India over a period of 3 years (2002-2004). After primary screening of rotaviruses by RNA electrophoresis in polyacrylamide gel, 200 of 412 samples negative by PAGE were screened by reverse transcription polymerase chain reaction for group B rotaviruses. The group B rotavirus positives samples were also confirmed by dot-blot hybridization.

RESULT

During the study period, we detected 37 (18.5%) sporadic cases of human group B rotavirus infection in children below 3 years of age of which 15 (7.5%) showed mixed infection with group A rotaviruses by RT-PCR. In dot-blot hybridization studies the RNA of all rotavirus positive samples hybridized with the nonisotopic psoralen-biotin labeled total RNA probe generated from a human group B rotavirus CAL-1 strain confirming the samples as group B rotaviruses.

CONCLUSION

The shift in age preference of group B rotavirus infection from adult to children and mixed infection of group B and group A rotaviruses reveals the importance of group B rotavirus as an etiological agent of childhood diarrhoea. Therefore, future vaccination strategy should include both group A and B rotaviruses to control rotavirus diarrhoea.

Molecular characterization of a porcine Group A rotavirus strain with G12 genotype specificity

A porcine Group A rotavirus strain (RU172) was detected and molecularly characterized during a surveillance study conducted for rotavirus infection in a pig farm located in a suburban area of Kolkata City, India. The G12 genotype specificity of RU172 was revealed by PCR-based genotyping assays following addition of a G12 type-specific primer (designed in our laboratory to pick up G12 isolates from field samples) and was confirmed by sequence analysis of the VP7-encoding gene. The RU172 strain exhibited maximum VP7 identities of 93.6% to 94.5% with human G12 strains at the deduced amino acid level. In spite of its G12 genotype nature, RU172 appeared to be distinct from human G12 rotaviruses and, on phylogenetic analysis, formed a separate lineage with human G12 strains. Among the other gene segments analyzed, RU172 belonged to NSP4 genotype B, had a NSP5 and VP6 of porcine origin, and shared maximum VP4 identities with porcine P[7] rotaviruses (94.3%-95.4% at the deduced amino acid level). Therefore, to the best of our knowledge, this is the first report of detection of an animal rotavirus strain with G12 genotype specificity. Detection of strains like RU172 provides vital insights into the genomic diversity of Group A rotaviruses of man and animals.

Sequencing and sequence analysis of VP7 and NSP5 genes reveal emergence of a new genotype of bovine group B rotaviruses in India

Three bovine group B rotavirus strains were detected from diarrheic calves during a surveillance study of rotaviral diarrhea in West Bengal, India. The sequence analysis of VP7 and NSP5 genes of these strains demonstrates a high degree of sequence variation from other group B rotavirus strains, indicating the emergence of a new genotype.

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Human group B rotavirus infections cause severe diarrhea in children and adults in Bangladesh

Human group B rotavirus was detected in 12 of 220 adult patients and 2 of 67 child patients with severe diarrhea in Bangladesh. Group B rotavirus may be virulent in both adults and children, and the virus may be an especially serious diarrheal agent in Bangladesh.

Molecular epidemiology of rotaviral infection in South Indian children with acute diarrhea from 1995-1996 to 1998-1999

The distribution of VP7 (G-) and VP4 (P-) genotypes among 126 rotavirus strains from South Indian children, < 5 years of age and with acute diarrhoea, presenting to a single hospital during the months to November and December, from 1995 to 1998, was studied. Multiplex hemi-nested G- and P-typing polymerase chain reactions determined 101 (80%) G types and 78 (61%) P types, respectively. In order of frequency, the commonest G types were G1, G4, G2, G9, G3, and G8, and P types were P1B[4], P1A[8], and P2A[6] and the most common G:P combinations were G1:P1A[8], G1:P1B[4], G2P1B[4] and G4:P1A[8]. G1, G2, and G4 types were seen in all years. The single G3 isolate was seen in 1998. The single G8 isolate and the 5 G9 isolates were seen in 1997, after a period of heavy rain. Sequence analysis showed that the G8 isolate was related most closely to the bovine strain A5, and the G9 strains were distinct from the nonpathogenic Indian isolate 116E and similar to G9s isolated in Mysore and the United Kingdom described previously.