Whole-genome characterisation of G12P[6] rotavirus strains possessing two distinct genotype constellations co-circulating in Blantyre, Malawi, 2008.

Rotavirus A strains detected in diarrhoeal children commonly possess any one of the genotypes G1, G2, G3, G4, and G9, with a recent increase in G12 detection globally. G12P[6] strains possessing short RNA (DS-1-like) and long RNA (Wa-like) migration patterns accounted for 27 % of the strains circulating in Blantyre, Malawi, between 2007 and 2008. To understand how the G12P[6] strains with two distinct genetic backgrounds emerged in Malawi, we conducted whole-genome analysis of two long-RNA and two short-RNA strains. While the former had a typical Wa-like genotype constellation of G12-P[6]-I1-R1-C1-M1-A1-N1-T1-E1-H1, the latter was found to have G12-P[6]-I2-R2-C2-M1-A2-N2-T2-E2-H2: a VP3 gene mono-reassortant on the DS-1-like backbone. Phylogenetic and Bayesian Markov chain Monte Carlo analyses showed that the short-RNA G12P[6] strains were generated around 2006 by reassortment between an African Wa-like G12P[6] strain donating three genes (the VP7, VP4, and VP3 genes) and a G2P[4] strain similar to the one circulating in Thailand or the United States of America that donated the remaining eight genes. On the other hand, the long-RNA strains were generated as a result of reassortment events within Wa-like G12 and non-G12 strains commonly circulating in Africa; only the VP4 gene was from a Malawian G8P[6] strain. In conclusion, this study uncovered the evolutionary pathways through which two distinct G12P[6] strains emerged in Malawi.

A first report on the characterization of rotavirus strains in Sierra Leone.

In an effort to reduce the high mortalities associated with rotavirus infections, a number of African countries are considering introducing human rotavirus vaccines. The demonstrated safety and efficacy of the live-attenuate human rotavirus vaccines in several clinical trials worldwide has accelerated such initiatives. Although the percentage-mortality rates for Sierra Leone are top of the list for rotavirus-associated deaths in Africa, no study has reported the prevalent strains circulating within this country. In this study, stool specimens were collected from 128 Sierra Leonean children presenting with diarrhea in 2005. Almost 37.5% (48/128) were rotavirus positive by EIA, of which 89.6% (43/48) revealed a short electropherotype, and a further 6.98% (3/48) could not be assigned a PAGE pattern. Genotyping analysis revealed G2P[4] (30.23%), G2P[6] (13.95%), G8P[6] (11.63%), G2P[8] (4.65%), G8P[4] (4.65%), and G8P[8] (2%) strains. About 11% were only assigned VP7 genotypes (G2), while 20.9% had mixed G and P types. The frequent detection of G2 rotaviruses could be of concern considering data generated from some studies that suggests lower efficacy of Rotarix® vaccine against G2 rotaviruses. This underscores the need for extensive and continuous regional strain surveillance to support rotavirus vaccines introduction and guide future vaccine development efforts. Such information will be useful before considering administration of specific rotavirus vaccine candidates in countries like Sierra Leone where little is known about circulating rotavirus strains.

[Evolution of group A Rotavirus strains circulating in Tunisia over a 3-year period (2005-2007)]. / Évolution des souches de Rotavirus du groupe A en circulation en Tunisie sur une période de trois ans (2005-2007).

BACKGROUND: Rotaviruses are the most frequent agents associated with diarrhoea in children worldwide. Analysis of mobility of the 11 segments of genomic RNA by polyacrylamide gel electrophoresis (PAGE) yields a pattern which is characteristic for a particular rotavirus isolate. The group A rotaviruses can be further characterized by analysis of VP7 and VP4 genes specificities, responsible for rotavirus classification into G and P genotypes, respectively. The aim of the present study was to determine the evolution of group A Rotavirus strains circulating in Tunisia over a 3-year period (2005-2007). MATERIAL AND METHODS: A total of 1503 stool samples collected from children less than five years old, consulting or hospitalised in Tunisia for diarrhoea between 2005 and 2007, were screened for the presence of group A Rotaviruses. Rotavirus-positive specimens were further analyzed by PAGE and G/P-genotyped by multiplex semi-nested RT-PCR. RESULTS: Rotaviruses were detected in 323 stool samples over 1503 (21 %). Long electropherotypes predominated in Tunisia during the whole period of study (N=158 vs N=82 short electropherotypes). VP7 genotyping showed the cocirculation of five different genotypes: G1, G2, G3, G4 and G9. VP4 typing detected four different P-genotypes: P[8], P[4], P[6] and P[11]. Rotavirus strains with G3P[8] specificity were predominating in Tunisia in 2005 and 2006, replaced by G2P[4] strains in 2007.

Relationship between electropherotypes and VP7/VP4 genotypes of group A rotaviruses detected between 2000 and 2007 in Tunisian children.

BACKGROUND: Rotaviruses are the most frequent agents associated with diarrhoea in children worldwide. Analysis of mobility of the 11 segments of genomic RNA by polyacrylamide gel electrophoresis (PAGE) yields a pattern which is characteristic for a particular rotavirus isolate. The group A rotaviruses can be further characterized by analysis of VP7 and VP4 genes specificities, responsible for rotavirus classification into G and P genotypes, respectively. The aim of the present study was to detect a relationship between electropherotype pattern and molecular characteristics of the rotavirus strains. MATERIAL AND METHODS: Were analyzed 278 rotavirus-positive specimens by PAGE and G/P-genotyped by multiplex semi-nested RT-PCR. Pearson's correlation tests were used for statistical analysis. RESULTS: Twelve different electropherotypes were visualized, eight with a long profile (186 cases) and four with a short one (87 cases). Concerning VP7 types, G2 viral strains were found to be predominant and were detected in 91 specimens (32.7%). Strains with G1, G3, G4, G8 and G9 specificities were detected in 62 (22.3%), 82 (29.5%), 13 (4.7%), two (0.7%) and seven cases (2.5%), respectively. The results of VP4 genotyping showed a predominance of P[8] genotype which comprised half of the strains identified (139 cases, 50%). VP4 P[4], P[6] and P[11] were found in 83 (29.9%), 31 (11.1%) and 11 (4.0%) specimens, respectively. A high rate of mixed strains was also found (1.8% mixed electropherotypes, 7.6% G-mixed and 5% P-mixed strains). Electropherotype pattern of rotavirus strains was significantly correlated with VP7 genotype (p=0.018) and with VP4 genotype specificities (p<0.001).

Characterization and molecular epidemiology of rotavirus strains recovered in Northern Pretoria, South Africa during 2003-2006.

Rotavirus infection is the most common cause of severe dehydrating gastroenteritis in infants and young children and remains a significant clinical problem worldwide. The severity and the burden of rotavirus disease could be reduced through the implementation of an effective vaccine. The aim of this study was to characterize rotavirus strains circulating in the local community as part of an ongoing hospital burden of disease study when a G1P[8] rotavirus vaccine candidate was being evaluated in the same community. From 2003 through 2006, 729 rotavirus-positive stool specimens were collected from children <5 years of age who were treated for diarrhea at Dr George Mukhari Hospital, Ga-Rankuwa, South Africa. Molecular characterization of the strains was performed by polyacrylamide gel electrophoresis and genotyping of the VP4 and VP7 alleles using well-established seminested multiplex reverse-transcription polymerase chain reaction methods. In 2003, 62% of strains exhibited the short rotavirus electropherotype, and the most common rotavirus strain was G2P[4]. In subsequent years, predominant rotavirus strains included G1P[8] and G1P[6] in 2004, G3P[8] and G3P[6] in 2005, and G1P[8] in 2006. For the 4 years of the study, rotavirus strains with P[6] genotype were detected in 25% of all rotavirus-positive specimens. In addition, unusual G12P[6] and G8 strains were detected at a low frequency. These results reflect the diversity of rotavirus strains circulating in South African communities.

Diversity of rotavirus VP7 and VP4 genotypes in Northwestern Nigeria.

BACKGROUND: Nigeria has recently been ranked third among the 10 countries with the greatest number of rotavirus disease-associated deaths per year. Estimates attribute up to 33,000 deaths annually to rotavirus disease in Nigerian children <5 years old. Although the introduction of the new oral, live attenuated rotavirus vaccines may not occur for another 4-6 years in developing countries, background data on burden of disease, cost of rotavirus disease, and characterization of circulating strains is required to hasten this introduction to children who would clearly benefit from the intervention. METHODS: Between July 2002 and July 2004, fecal specimens were collected from 869 infants and young children <5 years of age presenting with diarrhea in Kaduna, Kebbi, Sokoto, and Zamfara states in northwestern Nigeria. In addition, 194 control specimens were also collected from children matched for age. Specimens were screened for the presence of rotavirus antigens. Rotavirus-positive specimens were further analyzed to determine electropherotype, subgroup specificity, and G and P genotypes. RESULTS: Rotavirus was detected in 18% of children with diarrhea and 7.2% of the age-matched case control subjects. The highest rotavirus burden was detected in children aged <6 months. The majority of the rotavirus-positive specimens revealed viruses of long electropherotypes, subgroup II specificity, and G1P[8] genotypes. Furthermore, more than a quarter of specimens (37%) displayed mixed G and P genotypes, and almost a third could not be genotyped. CONCLUSIONS: The high numbers of mixed rotavirus infections highlight the multitude of enteric pathogens to which children in African countries are exposed. Data on circulating rotavirus strains serve to inform African government officials to the serious health threat posed by rotavirus in their respective countries and to document the diversity of strains before vaccine introduction.

Molecular characterization and genotyping of human rotavirus strains in Abidjan, Cote d'Ivoire.

In this study, we characterized human rotavirus strains recovered from infants and young children with acute diarrhea in Abidjan, Cote d'Ivoire, during 2000-2004. In total, 719 fecal specimens were collected from children aged 1-60 months with acute infantile gastroenteritis. Examination with a commercial enzyme-linked immunosorbent assay showed the presence of group A rotavirus antigen in 208 diarrheal specimens (28.9%). Polyacrylamide gel electrophoresis of the RNA extracted from rotavirus-positive stools yielded a variety of "long" and "short" RNA electropherotypes, which were used to help select strains for VP4 and VP7 genotyping. VP7 genotype G1 strains were circulating most commonly during the study period (53%), followed by G2 (22%) and G3 (5%) strains. Strains with multiple VP7 genotype reactivity were observed in 7.6% of specimens, and a similar number (8%) could not be typed at all. VP4 P[6] and P[8] strains circulated at similar levels (33%). Strains demonstrating multiple VP4 types were quite common (9%); however, 20% of the strains were untypeable by the methods used. Rotavirus strain diversity in Cote d'Ivoire was similar to that observed in other West African countries.

Comparison of 2 different regimens for reactogenicity, safety, and immunogenicity of the live attenuated oral rotavirus vaccine RIX4414 coadministered with oral polio vaccine in South African infants.

BACKGROUND: A phase II, randomized, double-blind, placebo-controlled study was conducted in South Africa during 2003-2004 to evaluate the safety, reactogenicity, and immunogenicity of 2 regimens of the live attenuated oral human rotavirus vaccine RIX4414 when coadministered with the Expanded Program on Immunization childhood vaccines, including oral polio vaccine. METHODS: Healthy infants were randomized (2:2:1) to receive either 2 doses of RIX4414 (n = 190; at 10 and 14 weeks, with placebo at 6 weeks), 3 doses of RIX4414 (n = 189; at 6, 10, and 14 weeks), or 3 doses of placebo (n = 96), all with concomitant routine vaccinations. The antirotavirus IgA seroconversion rate was assessed using enzyme-linked immunosorbent assay at 2 months after the last dose of RIX4414 or placebo. Antipolio types 1, 2, and 3 antibodies were measured using a virus neutralization assay. Solicited symptoms were recorded for 15 days after each dose. RESULTS: The antirotavirus IgA seroconversion rates were similar in the RIX4414 2- and 3-dose groups (44.3% and 44.4%, respectively; P = .544, by 1-sided Fisher exact test) and antirotavirus IgA geometric mean concentrations were also comparable. Seroprotection rates for antipolio types 1, 2, and 3 antibodies were high (93%-100%) and were not significantly different among groups. Solicited symptoms reported within 15 days after vaccination were similar in all groups. CONCLUSIONS: The immune seroconversion response to the RIX4414 vaccine with 3 doses was not superior to the 2-dose regimen. There was no interference by either regimen with antibody response to oral polio vaccine, and RIX4414 was well tolerated when given with routine vaccinations.

The detection and molecular characterization of human G12 genotypes in South Africa.

The last decade has seen an increase in the detection of rotavirus strains other than G1-G4 emerging or even predominating in some settings. The performance of the current rotavirus vaccines against unusual or rare circulating rotavirus serotypes cannot be predicted and continuous monitoring of wild type rotaviruses will remain a priority. Routine molecular rotavirus surveillance conducted in the Gauteng Province, South Africa during 2004, resulted in the detection of strains that could not typed using standard G specific genotyping primers. Sequencing of the first round amplicons revealed 19 serotype G12P[6] strains and one G12P[8] strain. Phylogenetic analyses of the G12 strains indicated that these strains are probably a recent introduction into South Africa and emerged from a strain related to the Indian isolate ISO-5. The association of the South African G12s with the P[6] genotype may suggest a mechanism for unusual strains to become more ecologically suited to local population transmission dynamics. This is the first report of serotype G12 strains on the African continent and continued surveillance will be required to track the emergence of G12 strains in Africa.

Genomic characterization of human rotavirus G8 strains from the African rotavirus network: relationship to animal rotaviruses.

Global rotavirus surveillance has led to the detection of many unusual human rotavirus (HRV) genotypes. During 1996-2004 surveillance within the African Rotavirus Network (ARN), six P[8],G8 and two P[6],G8 human rotavirus strains were identified. Gene fragments (RT-PCR amplicons) of all 11-gene segments of these G8 strains were sequenced in order to elucidate their genetic and evolutionary relationships. Phylogenetic and sequence analyses of each gene segment revealed high similarities (88-100% nt and 91-100% aa) for all segments except for gene 4 encoding VP4 proteins P[8] and P[6]. For most strains, almost all of the genes of the ARN strains other than neutralizing antigens are related to typical human strains of Wa genogroup. The VP7, NSP2, and NSP5 genes were closely related to cognate genes of animal strains (83-99% and 97-99% aa identity). This study suggests that the ARN G8 strains might have arisen through VP7 or VP4 gene reassortment events since most of the other gene segments resemble those of common human rotaviruses. However, VP7, NSP2 (likely), and NSP5 (likely) genes are derived potentially from animals consistent with a zoonotic introduction. Although these findings help elucidate rotavirus evolution, sequence studies of cognate animal rotavirus genes are needed to conclusively determine the specific origin of those genes relative to both human and animal rotavirus strains.

Role of astrovirus in intussusception in Nigerian infants.

Intussusception (IS) is a form of intestinal obstruction in which a segment of the bowel prolapses into a more distal segment. Viral infections, mostly adenovirus, enteroviruses, human herpesvirus and Epstein-Barr virus are reported in 20-50% of childhood cases of IS. Between January and July 2004, six stool specimens collected from infants 0- to 8-months old diagnosed and admitted for IS were investigated for the presence of rotavirus, astrovirus and adenovirus antigens. Astrovirus antigen was detected in three of the six stool specimens by enzyme immune assay (EIA) and confirmed in two specimens by reverse transcription-polymerase chain reaction (RT-PCR). Rotavirus, non-enteric adenovirus and astrovirus were detected by EIA, as mixed infections in a single specimen. The rotavirus strain revealed a SGI+II, mixed G1G2G8P[6] genotype and had no visible electrophoretic profile. A larger study is needed to determine the extent of involvement of astroviruses in IS in infants and the virus should be included in studies investigating the aetiology of IS.

Experiences with rotavirus vaccines: can we improve rotavirus vaccine impact in developing countries?

Rotavirus vaccines have been introduced into over 95 countries globally and demonstrate substantial impact in reducing diarrheal mortality and diarrheal hospitalizations in young children. The vaccines are also considered by WHO as "very cost effective" interventions for young children, particularly in countries with high diarrheal disease burden. Yet the full potential impact of rotavirus immunization is yet to be realized. Large countries with big birth cohorts and where disease burden is high in Africa and Asia have not yet implemented rotavirus vaccines at all or at scale. Significant advances have been made demonstrating the impact of the vaccines in low- and lower-middle income countries, yet the modest effectiveness of the vaccines in these settings is challenging. Current research highlights these challenges and considers alternative strategies to overcome them, including alternative immunization schedules and host factors that may inform us of new opportunities.

Epidemiology of rotavirus infection in north-western Nigeria.

Rotaviruses (RV) are associated with approximately 33 000 deaths in children <5 years of age annually in Nigeria. However, limited data exit on RV infection in north-western Nigeria. During July 2002 to July 2004, 1063 (869 diarrhoeic and 194 control) stool samples were collected from children <5 years of age presenting with diarrhoea in north-western Nigeria. The stools were analysed for RV antigen and further characterized by antigenic and genomic methods. RV was detected in 18% of children with diarrhoea and 7.2% of the age-matched case controls. The highest RV burden was detected in children <6-months-old. Long electropherotypes and VP6 subgroup I + II specificity predominated.

Epidemiology of rotavirus and astrovirus infections in children in northwestern Nigeria.

BACKGROUND: Recent estimates attribute 527,000 deaths in children less than five years of age to rotavirus diarrhea annually, with 145,000 occurring in sub-Saharan Africa. Human astroviruses have been identified as one of the most frequent causes of infantile diarrhea, second in incidence only to rotavirus. This study was conducted to determine the prevalence of rotavirus and astrovirus and also to establish the circulating strains of rotavirus in a community in Nigeria where most diarrheic patients do not visit clinics or health care centers. METHODS: A total of 154 stool samples (134 diarrheic and 20 non-diarrheic) were collected from infants and young children less than 5 years of age from January-March 2002. Samples were obtained by house-to-house visit in randomly selected districts in Zaria, Northwestern Nigeria. The samples were screened for rotavirus and astrovirus antigens using commercially available Enzyme Linked Immunosorbent Assay (ELISA) kits. All positive group A rotavirus samples were further subjected to VP6 sub-group ELISA, Polyacrylamide gel electrophoresis (PAGE) to determine their RNA electropherotypes and Reverse transcription polymerase chain reaction (RT-PCR) to determine their VP7 and VP4 genotypes. RESULTS: Rotavirus and astrovirus antigens were detected in 9% (12) and 5% (7) of the 134 diarrheic stool samples respectively. No viral antigen was detected in the non-diarrheic stools. Rotavirus infection was more common in younger children than astrovirus infection. VP6 sub-group II specificity (58.3%), long RNA electropherotypes (41.6%), VP7 genotype G1 (33.3%) and VP4 genotype P [6] (33.3%) were the most common strains in circulation at that time in the community. Of significance is the fact that a large proportion of the rotavirus strains in circulation could not be assigned either a VP6 subgroup or RNA electrophoretic pattern probably as a result of low viral load. CONCLUSION: In this community-based study, rotavirus and astrovirus were significantly associated with diarrhea. However, the prevalence of rotavirus infection among children appears to be low while that of astrovirus falls in the range seen in hospital-based studies around the continent.

Electropherotypes and subgroups of group A rotaviruses circulating among diarrhoeic children in Kano, Nigeria.

BACKGROUND: It is estimated that about 600,000 children die annually as a result of severe dehydrating diarrhea caused by rotaviruses. The virus is a double stranded RNA (dsRNA) virus with 11 segments. Group A rotaviruses show a characteristic 4-2-3-2 pattern following electrophoresis. The VP6 subgroups, I and II exist. This work was carried out to study the prevalence of rotavirus infection among children 0-5 years with diarrhea in Kano, and to determine the circulating subgroups and electropherotypes and of the rotavirus isolates. METHODS: Two hundred and eighteen stool specimens from children 0-60 months (198 diarrheic and 20 non-diarrheic) were collected from different hospitals and health care centers in Kano and subjected to group A rotavirus enzyme linked immunosorbent assay (ELISA) to determine presence of group A rotavirus, subgroup ELISA to determine the VP6 subgroups and polyacrylamide gel electrophoresis (PAGE) to determine the electropherotypes present. RESULTS: The long electropherotypes (47.05%) of four variations dominated over the short electropherotype (17.64%). About 11.76% of the isolates were of mixed infection. Dominance of subgroup II (45%) over subgroup I (25%), and the presence of both subgroups I and II (10%) and neither subgroup I nor II (15%) was observed in this study. CONCLUSION: Information on the genomic diversity of the RNA electropherotypes in this region, Kano, is reported in this study.

Rotavirus strain diversity in Eastern and Southern African countries before and after vaccine introduction.

BACKGROUND: The African Rotavirus Surveillance Network has been detecting and documenting rotavirus genotypes in the African sub-continent since 1998 in anticipation of the rollout of rotavirus vaccination in routine Expanded Programme on Immunisation. This paper reports distribution of the rotavirus strains circulating in 15 Eastern and Southern African (ESA) countries from 2010-2015 as part of active World Health Organization (WHO) rotavirus surveillance, and investigates possibility of emergence of non-vaccine or unusual strains in six selected countries post-vaccine introduction. MATERIAL AND METHODS: Stool samples were collected from children <5 years of age presenting with acute gastroenteritis at sentinel hospitals pre- and post-rotavirus vaccine introduction. Samples were tested for group A rotavirus using an enzyme immunoassay by the national and sentinel laboratories. At the WHO Rotavirus Regional Reference Laboratory in South Africa, molecular characterisation was determined by PAGE (n = 4186), G and P genotyping (n = 6447) and DNA sequencing for both G and P types (n = 400). RESULTS: The six-year surveillance period demonstrated that 23.8% of the strains were G1P[8], followed by G2P[4] (11.8%), G9P[8] (10.4%), G12P[8] (4.9%), G2P[6] (4.2%) and G3P[6] (3.7%) in 15 ESA countries. There was no difference in circulating strains pre- and post-rotavirus vaccine introduction with yearly fluctuation of strains observed over time. Atypical rotavirus G and P combinations (such as G1P[4], G2P[8], G9P[4] and G12P[4]) that might have arisen through inter-genogroup or inter-genotypes reassortment were detected at low frequency (2%). Close genetic relationship of African strains were reflected on the phylogenetic analysis, strains segregated together to form an African cluster in the same lineages/sub-lineage or monophyletic branch. CONCLUSION: There has been considerable concern about strain replacement post-vaccine introduction, it was not clear at this early stage whether observed cyclical changes of rotavirus strains were due to vaccine pressure or this was just part of natural annual fluctuations in the six ESA countries, long-term surveillance is required.

[Epidemiological and virological aspects Rotavirus diarrhoea in Abidjan, Côte d'Ivoire (1997-2000)]. / Aspects épidémiologiques et virologiques des diarrhées dues aux Rotavirus à Abidjan, Côte d'Ivoire (1997-2000).

Viruses, mainly rotaviruses are aetiological agents in more than 80% of the cases of acute diarrhoea in children. In order to determine the epidemiological characteristics and genotypes of human rotaviruses involved in gastroenteritis in diarrheic children aged from 0 to 5 years old in Abidjan, 642 specimens of stools were collected between 1997 and 2000 in the urban health centres and University Teaching Hospitals in Abidjan. The antigenic detection of rotaviruses carried out by ELISA test was followed by the antigenic (VP6 sub-groups) and molecular characterization: polyacrylamide gel electrophoresis and genetic typing. The general prevalence of Rotavirus diarrhoea was 27.9%. Among the children who were found positive, those whose age ranged from 0 to 11 months old accounted for 45.8% against 41.3% and 12.9% for those whose age ranged from 1 to 2 and 3 to 5 years old respectively proving thus the precocity of rotavirus infection. From an electrophoretypical and antigenic point of view 74.5% of 141 extracts of RNA had a "long" profile and belonged to the VP6 II sub-group against 24.8% of "short" profile belonging to sub-group I. The electrophoretypes with short profile were identified in majority in infants whose age ranged from 0 to 2 years old. Out of the P genotypes identified, the P [8] genotype (59.6%) was predominant followed by the P [6] genotype (26.2%), P [4] (2.8%) and one mosaic genotype P[6,8] which represented 11.4%. These results will need to be completed by the determination of VP7 genotypes in order to provide interesting information on rotaviruses before the introduction of anti-Rotavirus vaccines in the country.

[Prevalence of adenovirus antigens in children presenting with acute diarrhoea]. / Prévalence des antigènes d'adénovirus chez les enfants atteints de diarrhée aiguië.

Viral diarrhoea remains a major cause of childhood morbidity and mortality worldwide. Four major categories of viruses are now recognized as clinically important, including rotavirus, astrovirus, adenovirus, and calicivirus. This retrospective epidemiological study was conducted in the East centre part of Tunisia. A total of 638 stool samples were collected from children under 5 years of age presenting with acute diarrhoea at hospitals the East centre part of Tunisia between October 2003 and September 2005. All samples were analyzed using commercially available immunoenzymatic assay (EIA) kits to detect specific adenovirus antigens. Samples positive for adenovirus antigen were further screened using an ELISA technique allowing specific detection of species F enteric adenovirus types 40 and 41. Adenovirus was detected in 6% of the stools tested using ELISA. Among stool samples testing positive for adenovirus, 57% (20/35) were found to contain species F adenovirus types 40/41. In addition to diarrhoea that was present in all children studied, vomiting and fever were observed in 89% and 53% respectively and were associated with respiratory troubles in 32%. Enteric adenoviruses appear to play an important role in paediatric diarrhoea in Tunisia. Use of simple effective viral diagnostic techniques in paediatric hospitals could improve patient care by reducing unnecessary use of antibiotics.

Adenovirus infection in children with diarrhea disease in Northwestern Nigeria.

BACKGROUND: Adenoviruses, particularly enteric adenoviruses (EAds) type 40 (Ad40) and type 41(Ad41), can cause acute and severe diarrhea in young children worldwide. This study was conducted to delineate the epidemiological features of adenoviruses identified in children with gastroenteritis in Northwestern Nigeria. METHODS: All 282 specimens comprising 248 diarrheic and 34 non-diarrheic stools were randomly selected from 1063 stools previously analyzed for rotaviruses. These specimens were collected between July 2002 and July 2004 from children < 5 years of age. The specimens were screened for the presence of adenoviruses using monoclonal antibody-based Enzyme Immuno Assay (EIA), (Adenovirus RIDASCREEN r-Biopharm, UK) and the positive specimens were further examined for Ad40 and Ad41 using Premier Adenoclone -Type 40/41 EIA (Meridian Biosciences, USA). Negative staining electron microscopy was performed on selected specimens to confirm the presence of adenovirus particles. RESULTS: Adenovirus antigen was detected in 63/282 (23%) of the diarrheic diarrheic and in 6/34 (17.6%) of the non-diarrheic specimens. Adenoviruses were detected throughout the study period with most patients infected in the age group 25-36 months. The male-to-female ratio was 2.2:1 (43/20). Clinical features included fever (60%: 38/63), vomiting (56%: 35/63), mild dehydration (49%: 31/63), symptoms of upper respiratory tract infection (13%: 8/63) and abdominal pain (5%: 3/63). Analysis of stool specimen in adenovirus infected patients showed watery diarrhea in 87% (55/63), diarrhea with mucus in 19% (12/63) and diarrhea with mucus and blood in 3% (2/63). Ten (10) percent of the children were hospitalized due to gastroenteritis while 9 patients (14.3%) had co-infections with rotavirus. Human EAds were detected in 8% of specimens mainly in the dry season and among children older than 2 years. The principal symptoms were diarrhea (100%), dehydration (80%) and fever (80%). CONCLUSION: The findings of this study suggest that adenoviruses are important etiologic agents of gastroenteritis in Northwestern Nigerian children.

Molecular characterisation of the rotavirus strains prevalent in Maua, Meru North, Kenya.

BACKGROUND: Rotavirus is the most common cause of severe infantile diarrhoea disease in infants and young children below five years worldwide. Rotavirus is associated with high cases of morbidity and mortality and it is estimated that up to 650,000 deaths in young children occur annually in the less developed countries and approximately 150,000-200,000 deaths occur in Africa alone. OBJECTIVE: To characterise the circulating rotavirus strains in Maua, Meru North district, Kenya. DESIGN: A prospective study to investigate and characterise rotavirus serotypes/genotypes and electropherotypes in infants and children with severe diarrhoea hospitalised and/or attending the outpatient department of Maua Methodist Hospital during the period April 2004 to September 2005. SETTING: Maua Methodist Hospital, Meru North, Kenya. SUBJECTS: Faecal samples were collected from 135 infants and children with acute diarrhoea and were screened first for the presence of human Group A rotavirus antigen using commercially available enzyme linked immunosorbent assay kit (ELISA). The positive samples were evaluated by sodium dodecyl polycrylamide gel electrophoresis (SDS-PAGE) to determine the viral RNA electropherotype profile. Rotavirus strains were also genotyped using reverse transcriptase polymerase chain reaction (RT-PCR) of the VP7 gene. RESULTS: Assay of these samples with commercial ELISA showed that 17.8% (24/135) were positive for group A rotavirus antigen. Twenty of these ELISA positive samples were also analysed by SDS-PAGE of which 75% (15/20) gave detectable electropherotype pattern with the long electropherotype being predominant 80.0% (12/15) followed by the short RNA profile 20.0% (2/ 15). Seventeen of the ELISA positive samples were genotyped for VP7 and the results showed that G9 was the most predominant genotype comprising 47.1% (8/17) followed by G8 29.4% (5/17), GI 17.4% (3/17) and the mixed genotype was G8/G9 5.9% (1/17). Most patients with rotavirus infection were of the age of 3 - 60 months, with 79% being less than 18 months old. CONCLUSION: The overall prevalence of rotavirus infection in young children with diarrhoea hospitalised and/or attending the out-patient department of Maua Methodist Hospital was 17.8% with the predominant serotype being G9. These results show that rotavirus plays an important role in severe viral diarrhoea in young children in Maua Meru North district, Kenya. Furthermore, this high G9 rotavirus prevalence in Kenya may require vaccine trials to be held in Kenya so as to determine the efficacy of new rotavirus vaccine candidates that do not include the G9 serotype.