Campylobacter species are the most common cause of bacterial gastroenteritis in the developed world. However, comparatively few studies have determined the epidemiological features of campylobacteriosis in resource-poor settings.
A total of 1,941 faecal specimens collected from symptomatic (diarrhoeic) children and 507 specimens from asymptomatic (non-diarrhoeic) children hospitalised in Blantyre, Malawi, between 1997 and 2007, and previously tested for the presence of rotavirus and norovirus, was analysed for C. jejuni and C. coli using a real time PCR assay.
Campylobacter species were detected in 415/1,941 (21%) of diarrhoeic children, with C. jejuni accounting for 85% of all cases. The median age of children with Campylobacter infection was 11 months (range 0.1–55 months), and was significantly higher than that for children with rotavirus and norovirus (6 months and 7 months respectively; P<0.001). Co-infection with either rotavirus or norovirus was noted in 41% of all cases in the diarrhoeic group. In contrast, the detection rate of Campylobacter in the non-diarrhoeic group was 14%, with viral co-infection identified in 16% of children with Campylobacter. There was no association between Campylobacter detection rate and season over the 10 year period.
Using molecular detection methodology in hospitalised Malawian children, we have demonstrated a high prevalence of Campylobacter infection, with frequent viral co-infection. The burden of Campylobacter infection in young African children may be greater than previously recognised.
Rotavirus A causes severe diarrhoea in infants and young children worldwide. The migration pattern (electropherotype) of the double-stranded RNA genome upon polyacrylamide gel electrophoresis has been used to define “strains” in molecular epidemiology. In temperate countries, distinct electropherotypes (strains) appear after the annual, off-seasonal interruption of rotavirus circulation. In Nepal, rotavirus circulated year-round and an uncommon genotype G12P predominated and persisted, providing a unique opportunity to examine whether the same electropherotype (the same strain) persisted or new electropherotypes (new strains) emerged successively under the same G12P predominance. A total of 147 G12P rotaviruses, collected from diarrhoeal children in Nepal between 2007 and 2010, were classified into 15 distinct electropherotypes (strains). Of these, three electropherotypes (strains), LP1, LP24, and LP27, accounted for 10%, 32% and 38% of the G12P rotaviruses, respectively. Each of the three major strains successively appeared, dominated, and disappeared. This study provided new evidence for the hypothesis that rotavirus constantly changes its strains to predominate in the local population even under conditions where a single genotype predominates and persists. Such dynamic strain replacement, the constant takeover of one predominant strain by another, fitter strain, is probably gives a competitive edge to the survival of rotavirus in nature.
rotavirus; strain; electropherotype; genotype; molecular epidemiology
Rotaviruses are the most important cause of severe acute gastroenteritis worldwide in children <5 years of age. The human, G1P rotavirus vaccine Rotarix™ significantly reduced severe rotavirus gastroenteritis episodes in a Phase III clinical trial conducted in infants in South Africa and Malawi. This paper examines rotavirus vaccine efficacy in preventing severe rotavirus gastroenteritis, during infancy, caused by the various G and P rotavirus types encountered during the first rotavirus-season.
Healthy infants aged 5–10 weeks were enrolled and randomized into three groups to receive either two (10 and 14 weeks) or three doses of Rotarix™ (together forming the pooled Rotarix™ group) or three doses of placebo at a 6,10,14-week schedule. Weekly home visits were conducted to identify gastroenteritis episodes. Rotaviruses were detected by ELISA and genotyped by RT-PCR and nucleotide sequencing. The percentage of infants with severe rotavirus gastroenteritis caused by the circulating G and P types from 2 weeks post-last dose until one year of age and the corresponding vaccine efficacy was calculated with 95% CI.
Overall, 4939 infants were vaccinated and 4417 (pooled Rotarix™ = 2974; placebo = 1443) were included in the per protocol efficacy cohort. G1 wild-type was detected in 23 (1.6%) severe rotavirus gastroenteritis episodes from the placebo group. This was followed in order of detection by G12 (15 [1%] in placebo) and G8 types (15 [1%] in placebo). Vaccine efficacy against G1 wild-type, G12 and G8 types were 64.1% (95% CI: 29.9%; 82%), 51.5% (95% CI:-6.5%; 77.9%) and 64.4% (95% CI: 17.1%; 85.2%), respectively. Genotype P was the predominant circulating P type and was detected in 38 (2.6%) severe rotavirus gastroenteritis cases in placebo group. The remaining circulating P types comprised of P (20 [1.4%] in placebo) and P (13 [0.9%] in placebo). Vaccine efficacy against P was 59.1% (95% CI: 32.8%; 75.3%), P was 70.9% (95% CI: 37.5%; 87.0%) and P was 55.2% (95% CI: -6.5%; 81.3%)
Rotarix™ vaccine demonstrated efficacy against severe gastroenteritis caused by diverse circulating rotavirus types. These data add to a growing body of evidence supporting heterotypic protection provided by Rotarix™.
Trial registration number
Enteric viruses introduced from the community are major causes of these illnesses.
Viruses are the major pathogens of community-acquired (CA) acute gastroenteritis (AGE) in children, but their role in healthcare-associated (HA) AGE is poorly understood. Children with AGE hospitalized at Alder Hey Children’s Hospital, Liverpool, UK, were enrolled over a 2-year period. AGE was classified as HA if diarrhea developed >48 hours after admission. Rotavirus, norovirus, adenovirus 40/41, astrovirus, and sapovirus were detected by PCR. A total of 225 children with HA-AGE and 351 with CA-AGE were enrolled in the study. HA viral gastroenteritis constituted one fifth of the diarrheal diseases among hospitalized children and commonly occurred in critical care areas. We detected >1 virus in 120 (53%) of HA-AGE cases; rotavirus (31%), norovirus (16%), and adenovirus 40/41 (15%) were the predominant viruses identified. Molecular evidence indicated rotaviruses and noroviruses were frequently introduced into the hospital from the community. Rotavirus vaccines could substantially reduce the incidence of HA-AGE in children.
Rotavirus; norovirus; nosocomial; gastroenteritis; molecular; vaccine; viruses; research; UK; children
To assess diversity of rotavirus strains in Lilongwe, Malawi, we conducted a cross-sectional study of children with acute gastroenteritis, July 2005–June 2007. Serotype G12 was identified in 30 (5%) of 546 rotavirus-positive fecal specimens. The G12 strain possessed multiple electropherotypes and P-types, but their viral protein 7 sequences were closely related, indicating that reassortment has occurred.
Gastroenteritis; rotavirus; electropherotype; VP7; VP4; Malawi; dispatch
In anticipation of rotavirus vaccine introduction in Saudi Arabia, this study was undertaken to determine the distribution of the G and P genotypes of rotaviruses in order to examine whether there was any emerging serotype or unusual strain circulating in children in Saudi Arabia. Of 984 stool specimens collected between 17 April 2004 and 16 April 2005, rotavirus was detected by an enzyme-linked immunosorbent assay in 187 (19%) diarrheal children less than 5 years of age. Of these, 160 (86%) were classified into G and P genotypes as follows: G1P (44%), G2P (20%), G9P (11%), G12P (4%), and G3P (4%). RNA polyacrylamide gel electrophoresis identified 94 (50%) specimens as long RNA patterns, 30 (16%) specimens as short RNA patterns, and 1 mixed infection. Only a single long RNA electropherotype was identified for seven specimens containing G12P rotavirus. RNA-RNA hybridization demonstrated that the G12P strains were similar in their genomic constellation to locally cocirculating strains and to a Nepalese G12P strain. The Saudi Arabian G12 VP7 gene had a 99% nucleotide sequence identity with Nepalese and Indian G12 VP7 genes and belonged to the third lineage. This study is the first to describe the distribution of rotavirus G and P types and also the first to identify G9P and G12P strains in the country.
We report data regarding the molecular epidemiology of human astrovirus (HAstV) infections among children in Madagascar. In a 13-month study, 5 HAstV isolates were detected in fecal samples from 237 children (2.1%) by reverse transcription–PCR. Phylogenetic analysis showed the cocirculation of usual and unusual HAstVs.
Astrovirus; genogroup; child; Madagascar; dispatch
We identified 21 rotaviruses in 129 patients with diarrhea in a Brazilian city with high rotavirus vaccine coverage. All rotaviruses were genotype PG2 with 1 mixed infection with P[NT]G9. Although virus predominance could have occurred randomly, the vaccine may be less protective against PG2. Prospective surveillance is urgently needed.
Rotavirus; genotypes; diarrhea; Brazil; vaccine; dispatch
A national household survey was conducted in Malawi to determine awareness and use of a socially marketed water treatment product. In all, 64% of mothers were aware of the product, and 7% were using it. Both poor and rural mothers had lower awareness and use rates. Targeting promotion to rural populations could enhance program effectiveness.
Malawi; diarrhea; social marketing; dispatch
Of 237 children with acute gastroenteritis in Antananarivo, Madagascar, during May 2004–May 2005, 14 (≈6%) were infected with norovirus. Seasonality (November–December peak) was detected. Reverse transcription–PCR identified GII as the most common genogroup. GIs belonged to GI.1, GI.3, and GI.4. Noroviruses in Madagascar show extensive genetic diversity.
Calicivirus; norovirus; genogroup; gastroenteritis; child; Madagascar; research
Of 731 stool specimens collected from children with diarrhea in Kathmandu, Nepal, from August 2004 through July 2005, 170 (23.3%) tested positive for rotavirus. Reverse transcription–PCR, including a revised G12-specific primer set, identified 56 (32.9%) as G2P and 39 (23.0%) as G12 with P, P, or P.
rotavirus; serotype; genotyping; PCR; G12; molecular epidemiology; dispatch
In anticipation of a rotavirus vaccine in Nepal, this study was undertaken to determine the distribution of the G and P serotypes and electropherotypes of rotaviruses in order to examine if there is any emerging serotype or unusual strain circulating in children and adults in Nepal. Of 1,315 diarrheal stool specimens, rotavirus was detected by an enzyme-linked immunosorbent assay in 116 (17%) of 666 patients less than 5 years of age, in 18 (7%) of 260 patients 5 to 14 years of age, and in 19 (5%) of 358 patients 15 years of age and older. Approximately 75% of rotavirus diarrhea occurred in children less than 5 years of age. Approximately 70% of rotaviruses found in each of the three age groups belonged to serotype G1P. Interestingly, there were 29 (20%) G12 rotaviruses carrying either P or P and one (0.7%) G11 rotavirus carrying an unusual P genotype. RNA polyacrylamide gel electrophoresis discriminated 19 strains (electropherotypes), among which there were three codominant strains carrying G1P and long RNA patterns. Five electropherotypes were discriminated among G12 rotaviruses, all of which had long RNA patterns. The fact that 20% of rotaviruses were G12 strains carrying either P or P and had multiple electropherotypes suggest that G12 strains are not more rare strains but that they pose an emerging challenge to current and future vaccines. The presence of multiple strains as defined by electropherotypes suggests the richness of the rotavirus gene pool in Nepal, where unusual strains may continue to emerge.
Of 260 children with acute diarrhea in Erbil, Iraqi Kurdistan, 96 (37%) were infected with rotavirus. Reverse transcription–polymerase chain reaction identified G1, G4, G2, G9, P, P, and P as the most common genotypes. Eight G/P combinations were found, but PG1 and PG2 accounted for >50% of the strains.
Rotavirus; genotypes; diarrhea; children; Iraqi Kurdistan
An 840-bp fragment of the 18S rRNA gene was used to identify Cryptosporidium spp. recovered from human immunodeficiency virus (HIV)-infected and -uninfected patients from Kenya, Malawi, Brazil, the United Kingdom, and Vietnam. Initial identification was by Ziehl-Neelsen acid-fast staining. Confirmation was by nested PCR, targeting the most polymorphic region of the 18S rRNA gene. Genotyping was by restriction endonuclease digestion of the PCR product followed by nucleotide sequencing. Among 63 isolates analyzed, four genotypes of Cryptosporidium were identified; 75% of the isolates were of the C. parvum human genotype, while the potentially zoonotic species were of the C. parvum bovine genotype (21.7%), the C. meleagridis genotype (1.6% [one isolate]), and the C. muris genotype (1.6% [one case]). HIV-infected individuals were more likely to have zoonotic genotypes than the HIV-uninfected individuals. Among the C. parvum group, strains clustered distinctly into either human or bovine genotypes regardless of the geographical origin, age, or HIV status of the patients. The intragenotypic variation observed in the C. parvum human genotype was extensive compared to that within the C. parvum bovine genotype group. The variation within genotypes was conserved in all geographical regions regardless of the patients' HIV status. The extensive diversity within genotypes at the 18S rRNA gene locus may limit its application to phylogenetic analyses.