Water System Publications
water treatment and storage in the home: A practical new strategy to prevent waterborne
Mintz E, Reiff F, Tauxe R
many parts of the developing world, drinking water is collected from unsafe surface
sources outside the home and is then held in household storage vessels. Drinking
water may be contaminated at the source or during storage; strategies to reduce
waterborne disease transmission must safeguard against both events. We describe
a two-component prevention strategy, which allows an individual to disinfect drinking
water immediately after collection (point-of-use disinfection) and then to store
the water in narrow-mouthed, closed vessels designed to prevent recontamination
(safe storage). New disinfectant generators and better storage vessel designs
make this strategy practical and inexpensive. This approach empowers households
and communities that lack potable water to protect themselves against a variety
of waterborne pathogens and has the potential to decrease the incidence of waterborne
diseases remain a leading cause of illness and death in the developing world.1
Providing potable water for drinking and washing is critical to reducing, diarrheal
disease transmission in this setting.2 However, improving source water
quality alone does not always decrease diarrheal disease incidence.3
Providing a safe drinking water source may fail to reduce diarrhea because transmission
of diarrheal pathogens continues through foodborne or person-to-person routes
of spread or because people are exposed to contaminated water during bathing and
other activities. Drinking water also becomes contaminated after collection, either
during transport or storage in the home.
in source water quality generally depend on expensive, long-term, centralized
projects, such as construction of wells, water treatment plants, and water distribution
systems. During the World Health Organization's (WHO's) Drinking Water Supply
and Sanitation decade (1981 to 1990), an effort was made to increase access to
potable water in developing countries but was nearly outstripped by population
expansion and migration from rural to urban areas.4 Safe drinking water
for all remains an elusive and expensive goal.
1990, more than 1 billion people depended on rivers, streams, or other unsafe
surface sources for drinking water.4 In many developing countries,
even municipal piped well water is unsafe, because of inadequately maintained
pipes, low pressure, intermittent delivery, lack of chlorination, and clandestine
connections. For example, Vibrio cholerae was repeatedly isolated from unchlorinated
municipal water systems in Peru that caused large epidemics of cholera.5,6
In Guayaquil, Ecuador, even central chlorination of the municipal water system
was insufficient to maintain adequate free chlorine residuals at peripheral distribution
sites, and drinking unboiled municipal water remained a primary source of cholera.7
inexpensive strategy is available to improve household drinking water until piped
potable water is routinely available. The strategy has two components: water disinfection
at the time water is collected (point-of-use disinfection) and water storage in
vessels specifically designed to prevent recontamination (safe storage). However,
successful implementation of this strategy will require focused educational campaigns
stressing the role of contaminated water and domestic hygiene in disease transmission.8
When centralized water treatment systems are absent or inadequate,
the responsibility for making drinking water safe falls to community residents
by default. The traditional emergency prevention measure, boiling the water, is
economically and environmentally unsustainable. It takes a kilogram of firewood
to bring a liter of water to boil for a minute,9 and a person requires
a minimum of 2L of drinking water per day.10
fuel wood, such as kerosene and other fossil fuels, are expensive and also pose
environmental hazards,11,12 while practical and inexpensive solar powered
stills suitable for household use have not been developed. After cooling, boiled
water can easily be recontaminated, especially if it is transferred to a storage
Chemical disinfectants are a practical alternative
to boiling, although only the safest and least expensive disinfectants are suitable
for household use in the developing world. Chlorine gas, the most commonly used
disinfectant in water treatment plants, is hazardous ,and impractical. However,
sodium and calcium hypochlorite are relatively safe, easy to distribute and use,
inexpensive, and effective against most bacterial and viral pathogens.13
When added to water in tightly covered containers, volatilization is minimal and
hypochlorite disinfectants provide residual protection for many hours to days.14
Commercial laundry bleach solutions (primarily sodium hypochlorite) and commercial
bleaching powders (primarily calcium hypochlorite) are potential disinfectants.
However, these preparations frequently contain impurities or additives to improve
laundering that may be harmful if ingested. Concentrations of hypochlorite may
vary, making it difficult to prepare standard dosing instructions. Too high a
dose results in an unpleasant taste that may discourage use.
electrolysis cells have been developed that permit small-scale manufacture of
a standard 0.5% sodium hypochlorite solution from common salt and water. These
cells, which are easy to operate and can run on solar power, make local production
of disinfectant feasible almost anywhere.15 The cost of hypochlorite
solutions produced by these generators ranges from US $2.50 to $8 per kilogram
of available chlorine, depending on the costs of energy and salt and the production
method used. At the higher cost, disinfecting 40 L of water a day, enough for
the essential household purposes of a family of five, would cost about US $0.25
annually. A single generator can provide enough disinfectant for a town of 10,000
people and could eventually be incorporated into a municipal water treatment system
once pipes are installed.
chemical disinfectants that have been used much less widely than hypochlorite
also may have potential applications for point-of-use disinfection. These include
iodine and mixtures of oxidants generated on-site (composed of various chlorine
and oxygen-based compounds, such as ozone, chlorine dioxide, and short-lived free
radicals). Other water treatments that may be applicable in some settings include
floculation and acidification with aluminum potassium sulfate (alum potash), filtration
through sand or cloth, and the use of copper sulfate. However, none of these treatments
has demonstrated the safety and efficacy of chlorination. Disinfection can be
achieved with relatively little effect on the taste or smell of treated water
by using standard hypochlorite solutions to treat known volumes of water .10,14,16
Unpleasant odors and tastes can be further reduced by letting treated water stand
or by using mixed oxidants, which break down some of the organic byproducts of
EFFECT OF WATER DISINFECTION IN THE HOME
Many observations suggest that
treating water in the home can prevent illness. Recent epidemiologic studies57,17
have demonstrated that persons whose families boil drinking water at home are
at lower risk of cholera specifically and diarrhea in general. In one recent study,18
acidification of drinking water with citrus fruit juice also protected against
cholera. However, few formal prospective evaluations of point-of-use disinfection
one study conducted in Bangladesh,19 families of cholera patients were
visited after the patient's hospitalization. Half of the families were taught
to add alum potash to their stored household drinking water. In these households,
fewer family contacts became infected with V cholerae than among
families who did not use alum.
potash treatment of household water also was evaluated in Myanmar.20
Stored drinking water samples from 50 control households and from 50 households
where alum treatment was used were tested for fecal coliform bacteria. Mean fecal
coliform counts were similar in both households before the addition of alum but
were lower in the treatment households 24 and 48 hours after alum was added.
disinfection using 10% sodium hypochlorite was evaluated in Brazil in 1985.21
Twenty families (112 persons) who collected their drinking water from a contaminated
pond were randomly assigned to one of two groups. During the next 18 weeks, community
health workers collected information on diarrheal illness from each family during
thrice weekly household visits. For 9 weeks, sodium hypochlorite was added to
one group's stored drinking water and a placebo (distilled water) was added to
water used by the other group; treatment and placebo groups were switched during
the second half of the study. Mean fecal coliform counts were significantly higher
in placebo treated water samples than in samples of hypochlorite treated water.
No significant difference in the average number of days of diarrhea per person-year
was observed between the two groups, although the short duration, small sample
size, and high dropout rate limited the study's ability to detect an association.
EFFECT OF WATER, STORAGE IN THE HOME
The risk of diarrheal disease due
to contamination of drinking water during household storage:was noted in surveys
conducted by the WHO in the 1960s.22 The WHO team observed that "drinking
water taken from the piped supply was stored for cooling in earthen jars which
were, without exception, faecally contaminated. Thus, the availability of water
had little impact in reducing the number of cases of diarrhea." The observation
of water contamination during home storage has since been repeatedly confirmed.
Data on inhouse water contamination are available from three sources: observational
studies of stored water quality, field investigations of the impact of specific
behaviors and water vessel characteristics on water quality and on health, and
intervention studies using modified water storage vessels.
Studies of Domestic Water Quality
In a recent review of water contamination
occurring during home water storage, 11 observational studies showed that mean
coliform levels were substantially higher in household water containers than in
water sources, four studies showed coliform levels in water storage containers
and sources to be comparable, and only one study showed lower coliform levels
in storage containers than in watersources.23 In five other studies
in which paired samples from individual water sources and household storage containers
were compared, the results were similar; fecal coliform concentrations were generally,
and sometimes dramatically, higher in stored water than in source water .23,24
During the recent cholera epidemic in Peru, we sampled water from municipal
taps and from stored household water from these taps and noted a thousandfold
increase in mean fecal coliform counts.5
(thermotolerant) coliform bacteria may not be ideal indicators for fecal contamination.
25 In some field studies, recognized enteropathogens were identified
in stored water. For example, in Thailand, enterotoxigenic Escherichia coli
was recovered from a drinking water jar used to store rainwater26;
in Bangladesh, toxigenic V cholerae 01 was recovered from stored drinking
water collected from safe tube wells27; and in Calcutta, Deb et al28
isolated V cholerae 01 from stored water in 9% of households of cholera
patients and in 2% of control households. Deb et al28 observed that
"people generally took stored water from the [open] bucket by dipping. ..thus
resulting in contamination of otherwise safe water by their infected fingers."
a cholera epidemic in Bahrain in 1981, investigators identified V cholerae
01 in stored household drinking water.29 This isolation probably resulted
from postcollection contamination, since tap water samples in the same homes and
from all other tested water sources were negative for V cholerae. Similarly,
in Myanmar, toxigenic E coli was identified in two of 40 water samples
from household storage vessels but in none of 20 samples collected on the same
day from the water sources.24 In Egypt, two parasitic pathogens, Strongyloides
and Ascaris were isolated from 10% to 15% of water samples collected from
earthenware household storage vessels (Figure
1, A), but no pathogens were identified in source water samples.34
These studies indicate that contamination with pathogens as well as indicator
organisms occurs during home water storage.
1. Traditional water storage vessels and water storage vessels that have
been modified to reduce contamination during storage. Storage vessel A is a traditional
Egyptian zir30; B, plastic container used to sell vegetable oil in
Zambia31; C, traditional cantero from El Salvador; D, sorai used in
an intervention trial in India32; E, tin bucket used in an intervention
trial in Malawi33; and F, plastic container meeting the Centers for
Disease Control and Prevention/Pan American Health Organization design criteria
and used in an intervention trial in Bolivia.14,15
Investigations of Specific
Behaviors and Storage Vessel Characteristics
field investigations have identified behaviors or storage vessel characteristics
associated with contamination of water in the home or with disease resulting from
contamination. For example, researchers investigating epidemics in Malawi35
and Peru5,6 reported that patients were more likely than healthy control
subjects to live in households where stored drinking water was dipped out with
hands or utensils. Similarly, in a recent investigation of epidemic Shigella dysenteriae
type 1 infection in Zambia, stored water was more likely to be dipped out in patients'
homes and more likely to be poured in the homes, of healthy neighbors, suggesting
that hands and objects introduced into stored water were a source of contamination.31
In this study, healthy subjects often stored their water in a narrowmouthed plastic
vessel used to sell vegetable oil (Figure
1, B), whereas infected patients were more likely to use an open bucket into
which hands could be inserted.
design of a water storage vessel may help determine how well stored water is protected.
In 1992, a microbiological survey of water stored in Texas homes without municipal
water connections found coliform bacteria significantly less often in storage
vessels with openings less than 10 cm in diameter, from which water was typically
poured, than in containers with wider openings, into which hands and dipping utensils
could more easily be introduced.36
traditionally designed containers make contamination less likely. For example,
the narrownecked "cantero" or "tinaja" (Figure
1, C), a water storage vessel traditionally used in Central America, has a
pleasing shape that may help protect stored water from contamination.
contamination occurs, characteristics of the storage vessel may affect bacterial
survival in stored water. In inoculation experiments with African domestic water
storage vessels, V cholerae 01 survived as long as 7 days in clay pots,
22 days in plastic containers, and 27 days in metal drums.37 Not surprisingly,
survival times rarely exceeded 1 day in water with chlorine levels of 0.2 mg/L
Studies With Modified Water Storage Vessels
The effect of modifying the
design of a water storage vessel on behavior, contamination, and disease has been
assessed in several studies. In one study conducted in the Sudan,30
fecal indicator organisms were documented in more than 80% of water samples collected
from 350 zirs. The zir is a large earthenware jar in the form of an amphora used
in Egypt and the Sudan (Figure 1,
A).30 Water is removed with a cup or ladle from the top, which
is generally uncovered. To assess the impact of modifying traditional design,
three new zirs were filled with clean water and placed in public locations. One
had a tightly fitting lid and a faucet for withdrawing water. A second zir also
was equipped with a faucet but had a loosely fitting lid, permitting easy access
to the water from above. A third, traditional zir, had neither a faucet nor a
lid. After 2 days, water in the traditional zir and the loosely covered zir showed
evidence of fecal contamination. Water in the zir with the faucet and the tightly
fitting lid remained uncontaminated even after an entire month had passed.
et al32 enrolled 91 families of cholera patients in a prospective study
to determine whether the spread of cholera within households could be reduced.
Thirty families received "sorais," narrownecked earthenware pitchers
with spouts for home water storage (Figure
1, D), 31 families received chlorine tablets for use in their traditional
household water storage buckets, and 30 families served as controls (continuing
to use their traditional household storage buckets). Cholera infections detected
by stool culture were most common among members of control families (17.3%), less
common among families using chlorine tablets (7.3%), and least common among families
using the new sorais (4.4%).
another intervention study conducted in rural Thailand, 20 households received
verbal educational messages during visits by study field workers on handwashing
and domestic hygiene and were loaned new plastic water storage vessels with spigots.38
Educational messages alone were given to another 20 households in the same village,
and 20 households served as controls. Provision of the storage vessel appeared
to reinforce the educational messages; persons in this group were more likely
to put the educational messages into practice and had significantly fewer E
coli organisms detected by fingertip rinses. Water samples drawn from the
vessels with spigots were the least contaminated of all stored water samples,
suggesting that water handling within the home was the major source of stored
a refugee camp in Malawi, locally produced tin water storage vessels with covers,
spouts, and handles (Figure 1, E) were given
to 84 families in exchange for their existing containers.33 These families
were compared with 315 families who collected and stored water in open buckets
or clay pots. Although source water was free from fecal coliform bacteria, it
quickly became contaminated through hand contact during rinsing or transportation.
Fecal coliform counts were significantly lower in water from the new vessels compared
with control vessels. During the 2 month study, children younger than 5 years
in households using the new vessels experienced significantly fewer diarrheal
episodes than children in control households. Despite being unsuitable for many
household activities, such as washing clothes and bathing children, the intervention
vessels were generally preferred over other containers.
CRITERIA FOR WATER STORAGE VESSELS
A variety of different water storage
vessel designs may protect water. To guide the design and approval of water storage
vessels, the Centers for Disease Control and Prevention (CDC) and the Pan American
Health Organization (PAHO) have proposed the following working design criteria.15
For safe storage, a water storage vessel should have the following qualities:
Be constructed of translucent high-density polyethylene plastic or similar material
that is durable, lightweight, nonoxidizing, easy to clean, inexpensive, and able
to be locally produced;
Hold an appropriate standard volume (eg, 20 L) and have a stable base and a sturdy,
comfortable handle for easy carriage;
Have a single opening 5 to 8 cm in diameter with a strong, tightly fitting cover
that makes it easy to fill the container and add disinfectant but difficult to
immerse hands or utensils;
Have a nonrusting, durable, cleanable spigot for extracting water;
air to enter as water is extracted;
Have volume indicators and illustrations of safe water handling practices displayed
on the outside of the vessel (Figure 2).
2.lllustrated directions on how to fill the water storage vessel, add
the proper amount of disinfectant, and remove water for drinking can be attached
to the side of the vessel.
storage is eminently affordable. Water containers that meet the aforementioned
criteria have been purchased by the PAHO and the CDC for prices ranging from US
$4.60 to $7.25, depending on the place of manufacture and the transportation costs.
A container made of highdensity polyethylene may last an average of 5 to 10 years
and as long as 20 years, depending on wall thickness. This plastic is used to
make milk containers in the United States and is recyclable. Safe containers also
may be fabricated from other materials, such as earthenware or tin, but these
may offer some disadvantages compared with high-density polyethylene in terms
of durability, cost, weight, or other characteristics.
design criteria can be met in various ways, and different designs may be appropriate
for different situations. Designs for water storage vessels also can address public
health concerns other than enteric illness. For example, the point-of-use disinfection
and safe storage strategy may be integrated with filtration of household water
that is used for Guinea worm eradication in Africa and Asia.39 In Thailand,
plastic screen covers for water storage vessels were designed to prevent the entry
and breeding of Aedes aegypti, the mosquito vector of dengue fever.40
NEW COMBINED INTERVENTION
The available evidence suggests that contamination
of drinking water during storage in household vessels may contribute to disease
transmission, and that improvements in the design of household water storage vessels
coupled with pointofuse water treatment before storage can reduce this risk.
source water quality is poor, safe water storage vessels alone cannot make water
potable, but they can help to preserve water quality after treatment. A preliminary
field trial of a new plastic storage container (Figure
1, F) and point-of-use disinfection was conducted in La Paz, Bolivia, in 1993.14
Fortytwo families that relied on contaminated shallow wells for drinking water
were randomly allocated to serve as controls (using traditional water storage
containers generally wide-mouthed, uncovered, earthenware jars) or to receive
the new water vessel with or without a 5% calcium hypochlorite disinfectant solution.
During the study, fecal coliform bacteria and E coli were commonly detected
in stored water in control households and in households using the new vessel without
disinfectant. However, no fecal coliforms or E coli were detected in stored water
samples from households that used both the chlorille solution and the intervention
containers. The combined intervention enabled families to produce and store drinking
water that met WHO standards for microbiological quality from nonpotable water
manufacture and distribution of disinfectant solutions and water storage vessels
are complementary activities that can be closely coordinated. Standard concentrations
of disinfectant and standard water vessel volumes make dosing instructions simple.
Inexpensive devices that measure the concentration of chlorine in water can facilitate
quality control at the village level, while official endorsements by health ministries
can help promote the local production, distribution, and use of safe household
water storage vessels and disinfectants.
Several questions need answers before this strategy can be widely
- How much disease can be prevented?
with an experimental vaccine, randomized intervention trials are needed to measure
the protective effect of the strategy. Disease-specific prevention will likely
be greatest for diseases that are primarily waterborne (ie, cholera) and less
for those that are water washed (ie, shigellosis, scabies, and impetigo) or water
related (ie, malaria).3 Surveillance for nondiarrheal diseases that
are transmitted by contaminated drinking water, such as typhoid fever, hepatitis
A, and dracunculiasis, should also be included in largescale intervention trials.
the impact of the disease prevented outweigh the cost of the intervention ?
data suggest intervention costs are low. The annual cost per family for both a
special water storage vessel and the disinfectant, for the shortest estimated
useful life of the vessel and the highest cost of hypochlorite, would be between
US $1.17 and $1.62, an amount affordable almost anywhere in the world. A prevention
effectiveness model for a Bolivian community of 10,000, in which the intervention
was assumed to reduce diarrheal incidence by 20%, showed prevention of 600 cases
of diarrhea, 100 hospitalizations, and five deaths during a 3 year period, at
a net annual savings to society of US $184.41 More data from field
studies are needed to confirm these preliminary estimates.
can the strategy be adapted to local customs and conditions?
with most public health prevention efforts, sustained success will require changes
in human behavior. The principle of adding a standard volume of disinfectant to
a standard volume of water is like the preparation of oral rehydration solutions,
a widely used strategy for diarrheal disease treatment. As with oral rehydration
solutions, considerable education and social marketing will be needed. Because
the strategy is based on local production and consumption of a product, market
forces may be used to promote its success. Local cooperatives, microindustries,
and street vendor distribution networks may all have a role to play.
can existing disinfectants be improved?
ease of maintenance and repair, and cost of disinfectant generators will be critical
factors in the developing world. Further studies of new disinfectant solutions
are needed, particularly of combinations of mixed oxidants, to determine their
effectiveness against chlorineresistant microbes, such as Giardia and Cryptosporidium.
Differences in taste and smell also may be important in choosing a disinfectant.
can water storage vessels be improved?
experience grows, further modifications will be developed to improve the effectiveness
and acceptability of safe storage vessels. New designs can be field-tested using
water contamination as the end point. Meeting local demands for different shapes,
volumes, colors, and materials may enhance the appeal of the strategy.
what other arenas can this strategy be applied?
the developing world, the combined strategy may be suitable for homes, schools,
workplaces, markets where foods and beverages are prepared or sold, and health
care facilities, including oral rehydration treatment centers. In developed countries,
this intervention strategy can also be applied. For example, in Native American
village homes in the Yukon Kuskokwim Delta in Alaska, water is stored in 30 gallon
plastic trash barrels and drawn out by dipping.42 Prompted by high
rates of hepatitis A and diarrhea in village residents, the Indian Health Service
recently , placed water tanks with covers and spigots in 14 homes and taught residents
to add chlorine to each full tank. When existing water systems are temporarily
disabled by natural disasters or where transient populations are housed in substandard
conditions, as in many migrant worker camps, simple means to purify water could
TOWARD THE FUTURE
As long as households collect and store water from unsafe
sources, practical point-of-use disinfection methods are the
best means of
enabling access to potable water. When combined with safe storage vessels, this
strategy allows individuals, households, and communities to assume responsibility
for purifying their own water and engenders a sense of community empowerment and
self-determination. It offers a locally governable, economically viable, and environmentally
sound intervention for rural and urban areas where safe water is not yet available.
Water treated onsite and safely stored before use also can be put to good advantage
in food preparation, dish washing, handwashing, bathing, and other activities,
where it may reduce transmission of foodborne or waterwashed diseases. The changes
in cultural perceptions and behaviors induced by this intervention may improve
acceptability of subsequent health interventions such as latrines.
Latin America, the cholera epidemic has entered its fourth year, having caused
nearly 1 million cases and, 10,000 deaths; it is likely to continue for many years
to come.43 Elsewhere in the developing world, epidemic cholera remains
unchecked; 78 countries reported cholera to the WHO in 1993, more than ever before.44
Driven by the impetus of, epidemic cholera, sustainable measures to prevent waterborne
diseases could become part of everyday life in many homes in the developing world.
Further development of this simple household technology can potentially improve
health and quality of life while protecting the environment.
thank Paul Blake, MD, MPH, Anita HighsmIth, MS, Robert Quick, MD, MPH, and Leslie
Roberts, PhD, MSPH, of the Centers for Disease Control and Prevention and Linda
Venczel, PhD, and Vicente Witt of the Pan American Health organization for their
continued inspiration and encouragement. All illustrations courtesy of Lee Oakley,
Centers for Disease Control and Prevention.
Bern C, Martines J, de Zoysa I, Glass R. The magnitude of the global problem of
acute diarrheal disease: a tenyear update. Bull World Health Organ. 1992;70:705714.
Esrey SA, Potash JB, Roberts L, Schiff C. Effects of improved water supply and
sanitation on ascariasis, diarrhoea, dracunculiasis, hookworm infection, schistosomiasis,
and trachoma. Bull World Health Organ. 1991; 69: 609-621.
Briscoe J. The role of water supply in improving health in poor countries (with
special reference to Bangla Desh). Am J Clin Nutr. 1978; 31: 2100-2113.
Health Organization. The International Drinking Water Supply and Sanitation Decade:
End of Decade Review (as at December 1990). Geneva, Switzerland: World Health
Organization; 1992. WHO/CWS/92.12.
Swerdlow DL, Mintz ED, Rodriguez M, et al. Waterborne transmission of epidemic
cholera in Trujillo, Peru: lessons for a continent at risk. Lancet. 1992; 340:
Ries AA, Vugia DJ, Beingolea L, et al. Cholera in Piura, ,Peru: a modern urban
epidemic. J Infect Dis. 1992; 166: 1429-1433.
Weber T, Mintz E, Cafiizares R, et al. Epidemic cholera in Ecuador: multidrug-resistance
and transmission by water and seafood. Epidemiol Infect. 1994; 112: 111.
Stanton B, Black R, Engle P, Pelto G. Theorydriven behavioral intervention research
for the control of diarrheal diseases. Soc Sci Med. 1992; 35: 1405-1420.
Barua D, Merson MH. Prevention and control of, cholera. In: Barua D, Greenbough
WB, eds. Cholera. 2nd ed. New York, NY: Plenum Medical Book Co; 1992: 329-349.
and Sanitation for Health Project. Household water disinfection in cholera prevention.
In: Technical Note. Arlington, Va: Water Sanitation for Health Project; March
RH, Skillicorn P. Boiling of drinking water: can a fuel-scarce community afford
it? Bull World Health Organ. 1985; 63: 157-163.
deKonig HW, Smith KR, Last JM. Biomass fuel consumption and health. Bull World
1985; 63: 11-26.
Sosbey MD. Inactivation of health-related microorganisms in water by disinfection
processes. Water Sci Tech. 1989; 21: 179-195.
Quick R, Venczel L, Gonzalez 0, et al. Impact of narrownecked water vessels and
home chlorination on fecal coliform and E. coli colony counts in drinking water.
In: Program and abstracts of the 33rd Interscience Conference on Antimicrobial
Agents and Chemotherapy; October 1720, 1993; New Orleans, La. Abstract 1459.
Witt VM, Reiff FM. Estrategias Alternativas Para la Desinfeccion del Agua Aplicable
a Zonas Urbanas Marginales y Rurales. Washington, DC: Pan American Health Organization;
May 1993. Serie ambiental 13.
White GC. Handbook of Chlorination. 2nd ed. New York, NY: Van Nostrand Reinhold
Co; 1986: 328-338.
Blake P A, Ramos S, MacDonald KL, et al. Pathogenspecific risk factors and protective
factors for acute diarrheal disease in urban Brazilian infants. J Infect Dis.
1993; 167: 627-632.
Mujica O, Quick R, Palacios A, et al. Epidemic cholera in the Amazon: transmission
and prevention by food. J Infect Dis. 1994; 169: 1381-1384.
Khan MU, Khan MR, Hossain B, Ahmed QS. Alum potash in water to prevent cholera.
Lancet. 1984; 2: 1032.
Oo KN, Aung KS, Thida M, Khine WW , Soe MM, Aye T. Effectiveness of potash alum
in decontaminating household water. J Diarrhoeal Dis Res. 1993; 11: 172-174.
Kirchhoff LV, McClelland KE, Pinho MDC, Araujo JG, Sousa MAD, Guerrant RL. Feasibility
and efficacy of inhome water chlorination in rural northeastern Brazil. J Hyg
Camb. 1985; 94: 173-180.
Zilj WJ. Studies on diarrhoeal diseases in seven countries by the WHO diarrheoal
diseases study team. Bull World Health Organ. 1966; 35: 249-261.
VanDerslice J, Briscoe J. All coliforms are not created equal: a comparison of
the effects of water source and inhouse water contamination on infantile diarrheal
disease. Water Resources Res. 1993; 29: 1983-1995.
Han AM, Oo KN, Midorikawa Y, Shwe S. Contamination of drinking water during collection
and storage. Trop Geogr Med. 1989; 41: 138-140.
Hazen TC. Fecal coliforms as indicators in tropical waters: a review. Toxic Asses.
1988; 3: 461-477.
Taylor DN, Seriwatnana J, et al. Potential sources of enterotoxigenic Esherichia
coliin homes of children with diarrhoea in Thailand. Bull World Health Organ.
1987; 65: 207-215.
Spira WM, Kham MU, Saeed Y A, Sat tar MA. Microbiologic surveillance of intra-neighborhood
El Tor cholera transmission in rural Bangladesh. Bull Worlq Health Organ. 1980;
Deb BC, Sirkar BK, Sengupta SP, et al. Intra-familial transmission of Vibrio cholerae
biotype Eltor in Calcutta slums. Indian J Med Res. 1982; 76: 814-819.
Gunn RA, Kimball AM, Mathew PP, Dutta SR, Rifatt AHM. Cholera in Bahrain: epidemiological
characteristics of an outbreak. Bull World Health Organ. 1981; 59: 61-66.
Hammad ZH, Dirar HA. Microbiological examination of sebeel water. Appl Environ
Microbiol. 1982; 43: 1238-1243.
Tuttle J, Ries AA, Chimba RM, Perera CU, Bean NH, Griffin PM. Antimicrobial resistant
epidemic Shigelladysenteriae type 1 in Zambia: modes of transmission. J Infect
Dis. 1995; 171: 371-375.
Deb BC, Sircar BK, Sengupta PG, et al. Studies on interventions to prevent Eltor
cholera transmission in urban slums. Bull World Health Organ. 1986; 64: 127-131.
Roberts L, Chartier Y, Malenga G, Rolka H, Toole M. Prevention of household water
contamination in a refugee population, Malawi. In: Program and abstracts of the
43rd Annual Epidemic Intelligence Service Conference; April 1822, 1994; Atlanta,
Khairy AEM, Sebaie OE, Gawad AA, El Attar L. The sanitary condition ofrural drinking
water in a Nile Delta village, I: parasitological assesment of 'zir' stored and
direct tap water. J Hyg Camb. 1982; 88: 57-61.
Swerdlow DL, Malanga G, Begokyian G, et al. Epidemic of antimicrobial resistant
Vibrio cholerae 01 infections in a refugee camp, Malawi. In: Program and abstracts
of the 31st Interscience Conference on Antimicrobial Agents and Chemotherapy;
September 290etober 2, 1991; Chicago, Ill. Abstract 529.
Koehler JE , Ries A, Tauxe R, et al. Cholera risk assessment in Texas 'Colonias,'
El Paso County, 1991. In: Program and abstracts of the 42nd Annual Epidemic Intelligence
Service Conference; April 1923, 1993; Atlanta, Ga. Abstract.
Patel M, Isaacson M. Survival of Vibrio cholerae in African domestic water storage
containers. S Afr Med J. 1989; 76: 365-367.
Pinfold JV. Faecal contamination of water and fingertip-rinses as a method for
evaluating the effect of low-cost water supply and sanitation activities on faeco-oral
disease transmission, II: a hygiene intervention study in rural northeast Thailand.
Epidemiol Infect. 1990; 105: 377-389.
Hopkins DR, RuizTeben E. Strategies for dracunculiasis eradication. Bull World
Health Organ. 1991; 69: 53-3540.
Kittayapong P, Strickman D. Three simple devices for preventing development of
Aedes aegypti larvae in water jars. Am J Trop Med Hyg. 1993; 49: 158-165.
Miller M, Quick R, Mintz E, Tauxe R, Teutsch S. Solid stools and solvent citizens:
an effective solution for preventing diarrhea in developing countries. In: Program
and abstracts of the 34th Interscience Conference on Antimicrobial Agents and
Chemotherapy; October 46, 1994; Orlando, Fla. Abstract J244.
Faubion M. Water storage tank design could improve health. Yukon Kuskokwim Health
Cory Messenger. 1994; 56: 67.
World Health Organization. Cholera update, end of 1993. Wkly Epidemiol Rec. 1993;
Health Organization. Cholera in 1993. Wkly Epidemiol Rec. 1994; 69: 205-216.
E, Reiff F, Tauxe R. Safe water treatment and storage in the home: A practical
new strategy to prevent waterborne disease. JAMA 1995; 273: 948-953.