Tag Archives: diarrheal diseases

WASHplus Weekly on WASH-Related Diseases

This issue contains recent studies and resources on several WASH-related diseases: cholera, dengue, diarrhea, leptospirosis, neglected tropical diseases, malnutrition, and typhoid. Included are a just-published UNICEF cholera toolkit, an updated review of WASH-related diseases from DfID, typhoid case studies from Bangladesh and Fiji, and other resources. weekly2

The Centers for Disease Control and Prevention suggested the topic for this issue, and we welcome other suggestions for topics. Future issues will focus on menstrual hygiene management, innovation, water point mapping, mobile applications, and WASH in schools; more than 100 past issues of the Weekly are archived on the WASHplus website.

New Global Study Pinpoints Main Causes of Childhood Diarrheal Diseases

New Global Study Pinpoints Main Causes of Childhood Diarrheal Diseases, Suggests Effective Solutions

A new international study published today in The Lancet provides the clearest picture yet of the impact and most common causes of diarrheal diseases, the second leading killer of young children globally, after pneumonia. The Global Enteric Multicenter Study (GEMS) is the largest study ever conducted on diarrheal diseases in developing countries, enrolling more than 20,000 children from seven sites across Asia and Africa.

GEMS, coordinated by the University of Maryland School of Medicine’s Center for Vaccine Development, confirmed rotavirus – for which a vaccine already exists – as the leading cause of diarrheal diseases among infants and identified other top causes for which additional research is urgently needed. GEMS found that approximately one in five children under the age of two suffer from moderate-to-severe diarrhea (MSD) each year, which increased children’s risk of death 8.5-fold and led to stunted growth over a two-month follow-up period.

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Chrysomya putoria, a Putative Vector of Diarrheal Diseases

PLoS Neglevted Trop Dis, Nov 2012

Chrysomya putoria, a Putative Vector of Diarrheal Diseases

Steven W. Lindsay, et al.

Author Summary – While it is well recognized that the house fly can transmit enteric pathogens, here we show the common African latrine fly, Chrysomya putoria, is likely to be an important vector of these pathogens, since an average latrine can produce 100,000 latrine flies each year. Our behavioral studies of flies in The Gambia show that latrine flies are attracted strongly to human feces, raw beef and fish, providing a clear mechanism for faecal pathogens to be transferred from faeces to food. We used PCR techniques to demonstrate that these flies are carrying Shigella, Salmonella and E. coli, all important causes of diarrhea. Moreover our culture work shows that these pathogens are viable. Latrine flies are likely to be important vectors of diarrheal disease, although further research is required to determine what proportion of infections are due to this fly.

Background – Chrysomya spp are common blowflies in Africa, Asia and parts of South America and some species can reproduce in prodigious numbers in pit latrines. Because of their strong association with human feces and their synanthropic nature, we examined whether these flies are likely to be vectors of diarrheal pathogens.

Methodology/Principal Findings – Flies were sampled using exit traps placed over the drop holes of latrines in Gambian villages. Odor-baited fly traps were used to determine the relative attractiveness of different breeding and feeding media. The presence of bacteria on flies was confirmed by culture and bacterial DNA identified using PCR. A median of 7.00 flies/latrine/day (IQR = 0.0–25.25) was collected, of which 95% were Chrysomya spp, and of these nearly all were Chrysomya putoria (99%). More flies were collected from traps with feces from young children (median = 3.0, IQR = 1.75–10.75) and dogs (median = 1.50, IQR = 0.0–13.25) than from herbivores (median = 0.0, IQR = 0.0–0.0; goat, horse, cow and calf; p<0.001). Flies were strongly attracted to raw meat (median = 44.5, IQR = 26.25–143.00) compared with fish (median = 0.0, IQR = 0.0–19.75, ns), cooked and uncooked rice, and mangoes (median = 0.0, IQR = 0.0–0.0; p<0.001). Escherichia coli were cultured from the surface of 21% (15/72 agar plates) of Chrysomya spp and 10% of these were enterotoxigenic. Enteroaggregative E. coli were identified by PCR in 2% of homogenized Chrysomya spp, Shigella spp in 1.4% and Salmonella spp in 0.6% of samples.

Conclusions/Significance – The large numbers of C. putoria that can emerge from pit latrines, the presence of enteric pathogens on flies, and their strong attraction to raw meat and fish suggests these flies may be common vectors of diarrheal diseases in Africa.

WASHplus Weekly – Focus on WASH-Related Diseases

Issue 58 June 1, 2012 | Focus on WASH-Related Diseases

The World Health Organization lists more than 20 diseases that are related to water, sanitation, and hygiene (WASH) conditions. This issue focuses on three of those:

  • cholera,
  • diarrhea, and
  • typhoid fever

Information and resources for each of the three diseases include fact sheets, videos, recent peer-review studies, and links to additional resources. Future issues will focus on additional WASH-related diseases.

Epidemiological methods in diarrhoea studies—an update

Int. J. Epidemiol. (2011) doi: 10.1093/ije/dyr152

Epidemiological methods in diarrhoea studies—an update

Wolf-Peter Schmidt1, et al.

Background Diarrhoea remains a leading cause of morbidity and mortality but is difficult to measure in epidemiological studies. Challenges include the diagnosis based on self-reported symptoms, the logistical burden of intensive surveillance and the variability of diarrhoea in space, time and person.

Methods We review current practices in sampling procedures to measure diarrhoea, and provide guidance for diarrhoea measurement across a range of study goals. Using 14 available data sets, we estimated typical design effects for clustering at household and village/neighbourhood level, and measured the impact of adjusting for baseline variables on the precision of intervention effect estimates.

Results Incidence is the preferred outcome measure in aetiological studies, health services research and vaccine trials. Repeated prevalence measurements (longitudinal prevalence) are appropriate in high-mortality settings where malnutrition is common, although many repeat measures are rarely useful. Period prevalence is an inadequate outcome if an intervention affects illness duration. Adjusting point estimates for age or diarrhoea at baseline in randomized trials has little effect on the precision of estimates. Design effects in trials randomized at household level are usually <2 (range 1.0–3.2). Design effects for larger clusters (e.g. villages or neighbourhoods) vary greatly among different settings and study designs (range 0.1–25.8).

Conclusions Using appropriate sampling strategies and outcome measures can improve the efficiency, validity and comparability of diarrhoea studies. Allocating large clusters in cluster randomized trials is compromized by unpredictable design effects and should be carried out only if the research question requires it.

Kenyan scientists push for cleaner water to curb climate-linked disease

NAIROBI (AlertNet) – Medical scientists and environmental activists are urging the Kenyan government to speed up efforts to tackle climate-related diseases, which are on the rise in the east African nation.
The $15 billion national budget announced in June includes a strategy for responding to climate change with funding for projects to expand irrigation activities in dry areas and improve water quality, for example.
But some experts think it doesn’t go far or fast enough. A group of scientists has joined forces with the Forest Action Network (FAN) and Kenya Medical Research Institute (KEMRI) to lobby for urgent measures to deal with the impact of warmer temperatures and unpredictable rains on health.

Research carried out by KEMRI suggests waterborne diseases and malaria are on the rise, with the country’s recent drought making matters worse. In the northern region of Turkana, for example, communities have had to rely on shallow wells for their drinking water, which are often dirty.

Dominic Walubengo of FAN told AlertNet the civil society coalition hopes a draft policy strategy it has submitted to several politicians will be discussed in parliament by the end of the year, and form the basis for new laws to address the negative health effects of climate change.

Hopes for tougher action on environmental issues are rising as Kenya’s new constitution – approved in a referendum earlier this month and due to be promulgated on Friday – is regarded as more supportive of green policies.

The three-year drought, which eased with better short rains late last year, has also added to the urgency, as meteorologists fear another prolonged dry spell could be on the way.

Walubengo noted a rapid increase in waterborne diseases earlier this year, including cholera and diarrhoea, which can harm children’s longer-term health. Persistent diarrhoea leads to malnutrition and stunted growth, which can in turn undermine cognitive development, including education and productivity, according to KEMRI.

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UNICEF/WHO – Diarrhoea: Why children are still dying and what can be done

NEW YORK, 14 October 2009 – Despite the existence of inexpensive and efficient means of treatment, diarrhoea kills more children than AIDS, malaria and measles combined, according to a report issued today by UNICEF and the World Health Organization (WHO).

The report, titled Diarrhoea: Why Children Are Still Dying and What Can Be Done,  (Pdf) includes information on the causes of diarrhoea, data on access to means of prevention and treatment, and a seven-point plan to reduce diarrhoea deaths.  “It is a tragedy that diarrhoea, which is little more than an inconvenience in the developed world, kills an estimated 1.5 million children each year,” said UNICEF Executive Director, Ann M. Veneman.

“Inexpensive and effective treatments for diarrhoea exist, but in developing countries only 39 per cent of children with diarrhoea receive the recommended treatment.” Dr Margaret Chan, Director-General of WHO, said:  “We know where children are dying of diarrhoea. We know what must be done to prevent those deaths.  We must work with governments and partners to put this seven-point plan into action.”  Diarrhoea is a common symptom of gastrointestinal infection, which can have a variety of sources.

However just a handful of organisms are responsible for most acute cases of diarrhoea and one,  Rotavirus, is responsible for more than 40 per cent of all diarrhoea-related hospital admissions of children under five. A new vaccine for Rotavirus has been found to be safe and effective but is still largely unavailable in most developing countries. Though most episodes of childhood diarrhoea are mild, acute cases can lead to significant fluid loss and dehydration. This dehydration can lead to death unless fluids are quickly replaced. Oral rehydration therapy is the cornerstone of fluid replacement and the new low-osmolarity formula of oral rehydration salts (ORS) is a simple, inexpensive and life-saving remedy that prevents dehydration in children suffering diarrhoea.

Some 88 percent of diarrhoeal deaths worldwide are attributable to unsafe water, inadequate sanitation and poor hygiene. As of 2006, an estimated 2.5 billion people around the world were not using adequate sanitation facilities, and about 1 in 4 people in developing countries practiced open defecation.  Access to clean water and good hygiene practices are extremely effective in preventing childhood diarrhoea.  Hand washing with soap has been shown to reduce the incidence of diarrhoeal disease by over 40 per cent, making it one of the most cost-effective interventions for reducing child deaths caused by this neglected killer.

Thursday October 15 is annual Global Handwashing Day when millions of children and adults in over 80 countries will take part in activities to highlight this key intervention.  The overall health and nutrition of children is also critical to their susceptibility to diarrhoea and the damage it can cause.  Undernourished children are at higher risk of suffering more frequent, severe and prolonged episodes of diarrhoea, and repeated bouts of diarrhoea also place children at greater risk of worsening nutritional status.

The seven point plan to save the lives of children stricken by diarrhoea includes two treatment and five prevention elements.

The two treatment elements are:

1. fluid replacement to prevent dehydration; and

2. zinc treatments, which decrease the severity and duration of the attack.

The five prevention elements are:

1. immunization against rotavirus and measles;

2. early and exclusive breastfeeding and vitamin A supplementation;

3. handwashing with soap;

4. improved water supply quantity and quality; and

5. promoting community-wide sanitation.

Campaigns targeting childhood diarrhoea in the 1970s and 1980s achieved success by educating caregivers and scaling up oral rehydration therapy to prevent dehydration. The campaigns delivered promising results but following that success, focus shifted to other health problems. There is now an urgent need to shift attention and resources back to treating and preventing diarrhoea.

There is also an online version of the report on 7pointplan.org