***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract Objective To compare the effect on prevalence of diarrhoea and mortality of household based treatment of drinking water with flocculant-disinfectant , sodium hypochlorite , and st and ard practice s in areas with turbid water source in Africa . Design Cluster r and omised controlled trial over 20 weeks . Setting Family compounds , each containing several houses , in rural western Kenya . Participants 6650 people in 605 family compounds . Intervention Water treatment : flocculant-disinfectant , sodium hypochlorite , and usual practice ( control ) . Main outcome measures Prevalence of diarrhoea and all cause mortality . Escherichia coli concentration , free residual chlorine concentration , and turbidity in household drinking water as surrogates for effectiveness of water treatment . Results In children < 2 years old , compared with those in the control compounds , the absolute difference in prevalence of diarrhoea was –25 % in the flocculant-disinfectant arm ( 95 % confidence interval –40 to –5 ) and –17 % in the sodium hypochlorite arm ( –34 to 4 ) . In all age groups compared with control , the absolute difference in prevalence was –19 % in the flocculant-disinfectant arm ( –34 to –2 ) and –26 % in the sodium hypochlorite arm ( –39 to –9 ) . There were significantly fewer deaths in the intervention compounds than in the control compounds ( relative risk of death 0.58 , P = 0.036 ) . Fourteen per cent of water sample s from control compounds had E coli concentrations < 1 CFU/100 ml compared with 82 % in flocculant-disinfectant and 78 % in sodium hypochlorite compounds . The mean turbidity of drinking water was 8 nephelometric turbidity units ( NTU ) in flocculant-disinfectant households , compared with 55 NTU in the two other compounds ( P < 0.001 ) . Conclusions In areas of turbid water , flocculant-disinfectant was associated with a significant reduction in  diarrhoea among children < 2 years . This health benefit , combined with a significant reduction in turbidity , suggests that the flocculant-disinfectant is well suited to areas with highly contaminated and turbid water 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 sample s ( 134 diarrheic and 20 non-diarrheic ) were collected from infants and young children less than 5 years of age from January-March 2002 . Sample s were obtained by house-to-house visit in r and omly selected districts in Zaria , Northwestern Nigeria . The sample s were screened for rotavirus and astrovirus antigens using commercially available Enzyme Linked Immunosorbent Assay ( ELISA ) kits . All positive group A rotavirus sample s 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 sample s 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 A study was conducted on the circulation of potentially diarrheagenic Escherichia coli in two groups of children , both under the age of seven . The first group ( 548 children ) suffered from mild diarrhea and attended the Xipamanine Health Center of Maputo , in Mozambique . The second group ( 380 children ) included r and omly chosen , asymptomatic , children from the same population . A total of 503 E. coli strains were isolated from the two groups of children ( n=375 and 128 , respectively ) . All E. coli strains were genotypically and phenotypically screened . The presence of virulence-associated genes was assessed by a set of multiplex PCR specific for st and lt genes of enterotoxic Escherichia coli ( ETEC ) , eae and bfpA genes of enteropathogenic E. coli ( EPEC ) , stx(1 ) and stx(2 ) of enterohemorrhagic E. coli ( EHEC ) , ial of enteroinvasive E. coli ( EIEC ) and the species-specific gene uidA. Adhesion and citotoxicity of isolated E. coli were evaluated in vitro on different cell cultures . A total of 37 isolates harbored virulence-associated genes : 18 were classified as ETEC , ( 15 from symptomatic , and three from asymptomatic children ) , 16 as EPEC ( respectively , 13 and 3 ) and three EIEC in the symptomatic group . No stx(1 ) or stx(2 ) genes , associated with enterohemorrhagic E. coli were found . On the basis of the adhesion pattern on HeLa cells , 167 E. coli were classified as diffusely adhering , ( 125 in patients and 42 in controls ) and 67 as enteroaggregative , ( 50 and 17 , respectively ) . To the best of our knowledge , this is the first report in the literature on the circulation of potentially diarrheagenic E. coli in Mozambique Fecal sample s collected from 237 diarrheic infants in Kampala , Ug and a and from 159 healthy cattle from a ranch in the Central Region of Ug and a were investigated for the presence of Escherichia coli O157 and other types of Shiga toxin-producing E. coli ( STEC ) . E. coli O157 were not detected in 150 stool sample s from children which were cultivated on sorbitol MacConkey agar . A search for all types of STEC performed on 87 additional human stool sample s with an enzyme-immunoassay for Shiga toxins ( Premier EHEC ) was also negative . Forty-two stool sample s from infants were additionally investigated for enteropathogenic E. coli ( EPEC ) by DNA-hybridization with an eae-specific gene probe . Compared to STEC , EPEC were frequent and found in six ( 14.3 % ) of these 42 r and omly selected stool specimens . We were further interested in the role of cattle as a reservoir for STEC in Ug and a. STEC were isolated from 45 of 159 cattle from a herd in the Central Region of Ug and a. STEC strains from cattle belonged to 16 different O- and nine different H-types and nine O : H types were identical to those found in bovine STEC from other continents . Only one bovine STEC strain was positive for the eae-gene , and O-groups associated with enterohemorrhagic E. coli ( EHEC ) types ( O26 , O103 , O111 , O145 and O157 ) were not found . Our report demonstrates that STEC are not frequent in urban children in Ug and a , but domestic cattle were identified as an important natural reservoir for these organisms in this country In a prospect i ve study , 132 hospital out- patients presenting with bloody diarrhoea ( ' cases ' ) were evaluated in Malawi , Central Africa ; 73 out-patient tuberculosis suspects acted as controls . Most ( 100/132 , 76 % ) subjects reported an illness lasting < or = 5 d with > 5 bowel actions in the preceding 12 h ; 39/132 ( 30 % ) reported use of systemic antimicrobial drugs in the preceding week ; 57 % ( 74/130 ) had a body mass index < 20 ; 4 % ( 5/131 ) were febrile ; and 18/130 ( 13 % ) had one or more sign(s ) of dehydration . The 73 controls reported no diarrhoea and more systemic antimicrobial drug use ( P = 0.0003 ) , but were otherwise comparable to the subjects . All stool sample s from controls and 38/124 ( 31 % ) from cases were macroscopically normal . Only 32 % ( 40/124 ) of the cases had blood visible in the stool . Parasitic gut infections were found in 42/124 ( 34 % ) cases compared with 1/60 ( 2 % ) controls ( P < 0.0001 ) . The commonest parasite was Schistosoma mansoni . Bacterial cultures were positive in 32/124 ( 26 % ) of the subjects . Shigella dysenteriae ( Sd ) 1 accounted for 53 % ( 17/32 ) of these . All bacterial isolates were sensitive in vitro to nalidixic acid and ciprofloxacin , while only 18 % were sensitive to  cotrimoxazole  . Sd 1 with significant antimicrobial resistance continues to cause seasonal epidemics of dysentery in Malawi . During these , approximately two-thirds of patients presenting with bloody diarrhoea have no blood visible in the stool .  Nalidixic acid remains the drug of choice but its use should be restricted to patients at greatest risk of complicated shigellosis BACKGROUND Diarrhea is a major cause of preventable illness in sub-Saharan Africa . Although most cases of bacterial gastroenteritis do not require antimicrobial treatment , antimicrobial use is widespread . We examined the bacterial causes of diarrhea and monitored antimicrobial susceptibilities of isolates through clinic-based surveillance in a rural Kenyan community . METHODS From May 1997 through April 2003 , diarrheal stool sample s from persons presenting to 4 sentinel health centers were cultured by st and ard techniques for routine bacterial enteric pathogens , for which antimicrobial susceptibilities were determined . A r and om subset of specimens was also evaluated for diarrheagenic Escherichia coli . RESULTS Among stool specimens from 3445 persons , 1092 ( 32 % ) yielded at least 1 bacterial pathogen . Shigella species was most commonly isolated ( responsible for 16 % of all illnesses ; 54 % of isolates were Shigella flexneri ) . Campylobacter species and diarrheagenic E. coli predominated among children aged < 5 years and were progressively replaced by Shigella species with increasing age . With the exception of Campylobacter species , susceptibility to the antimicrobials used most widely in the community was low : < 40 % for all isolates tested and < 25 % for Shigella species . Most persons were treated with an antimicrobial to which their isolate was resistant . Susceptibility to specific antimicrobials was inversely proportional to the frequency with which they were prescribed . CONCLUSIONS The utility of available antimicrobials for treating bacterial diarrhea in rural western Kenya is substantially limited by reduced susceptibility . More judicious use of appropriate antimicrobials is warranted . Efforts to prevent illness through provision of clean water , improved hygiene , and vaccine development should be strengthened BACKGROUND Concomitant parasitic infections are common in the developing world , yet most studies focus on a single parasite in a narrow age group . We investigated the extent of polyparasitism and parasite associations , and related these findings to self-reported morbidity . METHODS Inhabitants of 75 r and omly selected households from a single village in western Côte d'Ivoire provided multiple faecal specimens and a  single finger prick blood sample . The Kato-Katz technique and a formol-ether concentration method were employed to screen faecal sample s for Schistosoma mansoni , soil-transmitted helminths and intestinal protozoa . Giemsa-stained blood smears were analysed for malaria parasites . A question naire was administered for collection of demographic information and self-reported morbidity indicators . RESULTS Complete parasitological data were obtained for 500/561 ( 89.1 % ) participants , similarly distributed among sex , 
    Output:
    
This is the first review to look at the range of enteric pathogens circulating in SSA , and has confirmed high rates of isolation of pathogens from diarrhoeal cases .