Epidemic dysentery in western Kenya

[Spatio-temporal dynamics of bacillary dysentery outbreaks in Democratic Republic of the Congo, 1999-2013]

PROBLEM STATEMENT

From 1999 to 2013 in the Democratic RC, monitoring of bacillary dysentery in bloody diarrhea revealed an average rate of attack in 620 out of 100,000 inhabitants. Within the study period, biological confirmation was available in less than 1% of cases. A dozen dysentery outbreaks were confirmed in laboratories as shigellosis. In this study, our objective is to improve dysentery surveillance.

METHODS

A descriptive method based on epidemiological and biological data was applied, and a literature review was included.

RESULTS

According to historical research, the first dysentery epidemics occurred in the Mayombe Region in the early 1920s. Spatial dynamics show that the eastern part of the country experienced the highest number of attacks. Time series of bloody diarrhea in the country have revealed a decrease since 2005. No seasonality was found.

CONCLUSION

Shigellosis outbreaks have become rare and of low magnitude. Our results suggest a need for further exploration of the causes and determinants of high incidences of bloody diarrhea. Present-day diminution of shigellosis outbreaks calls for research into explanatory factors.

Relations between Household Livestock Ownership, Livestock Disease, and Young Child Growth

BACKGROUND

In resource-limited settings in which child malnutrition is prevalent, humans live in close proximity to household livestock. However, the relation between household livestock and child nutrition represents a considerable knowledge gap.

OBJECTIVE

We assessed whether household livestock ownership or livestock disease episodes were associated with growth in young children in western Kenya.

METHODS

We incorporated monthly anthropometric measurements for children <5 y of age into an ongoing linked human and animal surveillance cohort in rural western Kenya. Using linear mixed models adjusted for age, sex, and household wealth, we tested whether baseline household livestock ownership was related to baseline child height for age or prospective growth rate. We also evaluated whether livestock disease episodes were associated with child growth rate over 11 mo of follow-up.

RESULTS

We collected data on 925 children over the course of follow-up. Greater household livestock ownership at baseline was not related to baseline child height-for-age z score (adjusted β: 0.01 SD; 95% CI: -0.02, 0.04 SD) or child growth rate (adjusted β: 0.02 cm/y; 95% CI: -0.03, 0.07 cm/y). Livestock disease episodes were not significantly associated with child growth across the entire cohort (adjusted β: -0.007 cm/mo; 95% CI: -0.02, 0.006 cm/mo). However, children in households with livestock digestive disease between June and November gained less height than did children in households that did not report livestock disease (β: -0.063 cm/mo; 95% CI: -0.112, -0.016 cm/mo). Children <2 y of age in households with livestock digestive disease gained less weight than did those who did not report disease (β: -0.033 kg/mo; 95% CI: -0.063, -0.003 kg/mo).

CONCLUSION

In this cohort of young children in western Kenya, we did not find an association between ownership of livestock and child growth status. However, disease episodes in household livestock may be related to a lower child growth rate in some groups.

Surveillance for enteric pathogens in a case-control study of acute diarrhea in Western Kenya

BACKGROUND

Acute diarrhea remains a major public health problem in East African nations such as Kenya. Surveillance for a broad range of enteric pathogens is necessary to accurately predict the frequency of pathogens and potential changes in antibiotic resistance patterns.

METHOD

Stool samples were collected from September 2009 to September 2011; 193 and 239 samples, from age-matched cases and asymptomatic controls, were collected, respectively, from Kericho and Kisumu District Hospitals in western Kenya. Bacterial pathogens were identified by conventional microbiological methods; antibiotic susceptibility of bacterial isolates was ascertained using the MicroScan WalkAway 40 Plus. An enzyme immunoassay kit was used to detect rotavirus, and ova and parasite examination was conducted by microscopy and an enzyme immunoassay.

RESULTS

Rotavirus (10.2% and 10.5%) and Shigella (11% and 8%) were isolated significantly more often in the cases than the controls from Kericho and Kisumu District Hospitals respectively. The diarrheagenic Escherichia coli, Campylobacter jejuni and Salmonella were found most often in the cases while Giardia lamblia and Entamoeba histolytica/E. dispar were found more often in the controls. Most pathogens were isolated from children under 5 years old. More than 50% of the Shigella, Salmonella and diarrheagenic E. coli isolates were multidrug resistant to ampicillin, tetracycline and trimethoprim/sulfamethoxazole with several enteroaggregative and enterotoxigenic E. coli isolates producing extended-spectrum beta-lactamases.

CONCLUSION

Accurate epidemiologic information on acute diarrheal illness in Kenya will be critical for augmenting existing diarrhea management policies in terms of treatment and to strengthen future community awareness and health promotion programs.

Prevalence of gastrointestinal pathogens in Sub-Saharan Africa: systematic review and meta-analysis

A significant proportion of vulnerable people in sub-Saharan Africa (SSA) remain at risk for contracting diarrhoeal diseases due to the presence of many risk factors facilitating their transmission. A systematic review of published articles from the SSA region was done to determine the prevalence and types of diarrhoeal pathogens in circulation, based on a search of databases, including EBSCO host, PubMed, Scopus, Science Direct, Google scholar and Web of Science was done between September 2009 and December 2010. Data were summarized from 27 studies, with pooled data analysed and reported. Pathogens were isolated from between 26.8–65.6% of cases, with an overall isolation rate of 55.7% (95% CI, 48.2–62.9%). Isolation rates were highest amongst adult cases followed by children, and the odds of isolating a pathogen was greater in diarrhoeal cases (Odds Ratio 4.93 (95% CI, 1.99 to 12.23), than in asymptomatic controls. Overall isolation ranged from 8% to 99%; and heterogeneity testing suggests differences between age groups (Q=5.806; df=2, P=0. 055). Mixed E. coli spp., (29.95%), Cryptosporidium (21.52%), Cyclospora (18%), Entamoeba. (13.8%), Shigella spp. (10.49%), Salmonella spp. (8.36%), and Campylobacter spp. (8.33%), were most commonly reported, and rotavirus was the most common virus isolated. 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. Public health practitioners can use this information to understanding the challenges related to diarrhoeal illness and set priorities for their prevention and control.

Using European travellers as an early alert to detect emerging pathogens in countries with limited laboratory resources

Background

The volume, extent and speed of travel have dramatically increased in the past decades, providing the potential for an infectious disease to spread through the transportation network. By collecting information on the suspected place of infection, existing surveillance systems in industrialized countries may provide timely information for areas of the world without adequate surveillance currently in place. We present the results of a case study using reported cases of Shigella dysenteriae serotype 1 (Sd1) in European travellers to detect "events" of Sd1, related to either epidemic cases or endemic cases in developing countries.

Methods

We identified papers from a Medline search for reported events of Sd1 from 1940 to 2002. We requested data on shigella infections reported to the responsible surveillance entities in 17 European countries. Reports of Sd1 from the published literature were then compared with Sd1 notified cases among European travellers from 1990 to 2002.

Results

Prior to a large epidemic in 1999–2000, no cases of Sd1 had been identified in West Africa. However, if travellers had been used as an early warning, Sd1 could have been identified in this region as earlier as 1992.

Conclusion

This project demonstrates that tracking diseases in European travellers could be used to detect emerging disease in developing countries. This approach should be further tested with a view to the continuous improvement of national health surveillance systems and existing European networks, and may play a significant role in aiding the international public health community to improve infectious disease control.

Surveillance for Bacterial Diarrhea and Antimicrobial Resistance in Rural Western Kenya, 1997-2003

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 samples from persons presenting to 4 sentinel health centers were cultured by standard techniques for routine bacterial enteric pathogens, for which antimicrobial susceptibilities were determined. A random 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.

Case management of a multidrug-resistant Shigella dysenteriae serotype 1 outbreak in a crisis context in Sierra Leone, 1999-2000

From December 1999 to the end of February 2000, 4218 cases of dysentery were reported in Kenema district, southeastern Sierra Leone, by a Médecins Sans Frontières team operating in this region. Shigella dysenteriae serotype 1 was isolated from the early cases. The overall attack rate was 7.5% but higher among children under 5 years (11.2%) compared to the rest of the population (6.8%) (RR = 1.6; 95% CI 1.5-1.8). The case fatality ratio was 3.1%, and higher for children under 5 years (6.1% vs. 2.1%) (RR = 2.9; 95% CI 2.1-4.1). A case management strategy based on stratification of affected cases was chosen in this resource-poor setting. Patients considered at higher risk of death were treated with a 5 day ciprofloxacin regimen in isolation centres. Five hundred and eighty-three cases were treated with a case fatality ratio of 0.9%. Patients who did not have signs of severity when seen by health workers were given hygiene advice and oral rehydration salts. This strategy was effective in this complex emergency.

Clonal multidrug-resistant Shigella dysenteriae type 1 strains associated with epidemic and sporadic dysenteries in eastern India

Multidrug-resistant strains of Shigella dysenteriae type 1 were implicated in three outbreaks and sporadic cases of dysentery in eastern India in 2002 and 2003. After a hiatus of 14 years, this pathogen reemerged with an altered antibiotic resistance pattern. In addition to ampicillin, co-trimoxazole, tetracycline, chloramphenicol, and nalidixic acid, all the recent strains were resistant to norfloxacin, lomefloxacin, pefloxacin, and ofloxacin and showed reduced susceptibility to ciprofloxacin. Pulsed-field gel electrophoresis identified a new clone of S. dysenteriae type 1 that was associated with the recent outbreaks and sporadic cases. Based on the spatial and temporal spread of multidrug-resistant S. dysenteriae type 1, we predict that this clonal type may spread further in this region.

Shigella dysenteriae serotype 1, Kolkata, India

Since July 2002, bacteriologically confirmed shigellosis cases have increased, and multidrug-resistant Shigella dysenteriae serotype 1 strains have reemerged in patients hospitalized with diarrhea in Kolkata, India. The isolated strains of S. dysenteriae 1 showed resistance to chloramphenicol (80%), ampicillin (100%), tetracycline (100%), co-trimoxazole (100%), nalidixic acid (100%), norfloxacin (100%), and ciprofloxacin (100%). Emergence of fluoroquinolone resistance in S. dysenteriae 1 strains complicated treatment of shigellosis patients. Six strains belonging to provisional serovars of S. dysenteriae were also identified for the first time in patients hospitalized with diarrhea in Kolkata, India.

Surveillance of bacterial pathogens of diarrhea disease in Indonesia

Emerging or reemerging infections due to bacterial disease may be a local, regional or global problem. Bacterial acute gastroenteritis is a potential cause of substantial morbidity in travelers and deployed U.S. military personnel. A surveillance study was conducted over a two-year period in Indonesia among 6760 patients with debilitating diarrheal diseases. Of the 6,760 patients, 587 (9%) of the patient stools were positive for bacteria. The proportions of bacteria isolated from the 587 patients were: Shigella flexneri (39%), Salmonella spp. (26%), Vibrio spp. (17%), S. sonnei (7%), Campylobacter jejuni (4.4%), Salmonella typhi (3%) and S. dysenteriae (2.3%). Shigella flexneri was the most prevalent pathogen isolated, over Vibrio spp. No V. cholerae was isolated in the cities of Pontianak, Padang or Batam in Indonesia. Shigella dysenteriae reemergence was noted in Bali, Kalimantan, Batam and Jakarta after an absence of 15 years. Isolation of a high proportion of S. flexneri, and Vibrio spp. occurred during the rainy months. All bacterial isolates were susceptible to quinolones, with the exception of C. jejuni and Salmonella spp., which were resistant to ciprofloxacin, norfloxacin and nalidixic acid. Our findings highlight the decline of V. cholerae, the rise of S. flexneri and the reemergence of S. dysenteriae in Indonesia. The study also documents the emergence of quinolone-resistant Campylobacter spp. in the Indonesia archipelago.

Shigella spp. surveillance in Indonesia: the emergence or reemergence of S. dysenteriae

From June 1998 through November 1999, Shigella spp. were isolated in 5% of samples from 3,848 children and adults with severe diarrheal illness in hospitals throughout Indonesia. S. dysenteriae has reemerged in Bali, Kalimantan, and Batam and was detected in Jakarta after a hiatus of 15 years.

Factors contributing to the emergence of Escherichia coli O157 in Africa

In 1992, a large outbreak of bloody diarrhea caused by Escherichia coli O157 infections occurred in southern Africa. In Swaziland, 40,912 physician visits for diarrhea in persons ages >5 years were reported during October through November 1992. This was a sevenfold increase over the same period during 1990-91. The attack rate was 42% among 778 residents we surveyed. Female gender and consuming beef and untreated water were significant risks for illness. E. coli O157:NM was recovered from seven affected foci in Swaziland and South Africa; 27 of 31 patient and environmental isolates had indistinguishable pulsed-field gel electrophoresis patterns. Compared with previous years, a fivefold increase in cattle deaths occurred in October 1992. The first heavy rains fell that same month (36 mm), following 3 months of drought. Drought, carriage of E. coli O157 by cattle, and heavy rains with contamination of surface water appear to be important factors contributing to this outbreak.