Diarrhea, caused by waterborne Entamoeba, Giardia, Cryptosporidium and Cyclospora Paul R. Earl Facultad de Ciencias Biol

1
Diarrhea, caused by waterborne Entamoeba,
Giardia, Cryptosporidium and CyclosporaPaul R.
EarlFacultad de Ciencias BiológicasUniversidad
Autónoma de Nuevo LeónSan Nicolás, NL 66451,
Mexico
2
These waterborne protozoa have cysts and of
course trophozoites (mobile forms). They are not
killed by the common chlorine treatment of
drinking water. Then we are concerned with water
management and drainage from the public health
point of view.
Cryptosporidium parvum is a
parasite with cysts smaller that a red blood cell
of 7 microns, whereas Cyclospora, Entamoeba
histolytica and Giardia lamblia have cysts of 10
or more microns. All 4 of these protozoans can
cause diarrhea and are resistent to chlorination.
Except for the flagellate and the ameba, the 2
other protozoans belong to the Order Eimeriida.
3
Water management. There are 2 traditional ways
of treating wastewater a) it is left in
stabilization ponds (settling tanks) until the
solid matter it contains has settled as sediment,
and b) as activated sludge where air is blown
through the water so that microbes convert more
organic matter. In both cases, black sludge
accumulates, therefore look for a better
way.These parasitic diseases sometimes may seem
remote from the massive problem of supplying
cities with enough clean water, and sometimes
supplying the countryside with safe fertilizer.
4
Soil erosion is another major problem related to
water management. Silt in rivers by high runoffs
as from mountains and high sedimentation rates
leads to senescent lakes that are eventually
filled in. The diversion of country waters to the
cities by deep wells and canalization makes the
land drier, i. e., sometimes creates more desert.
Many lakes, dams and rivers contain overloads of
sewage (human feces) that make them a health
hazard. In Spanish this drainage is called aguas
negras. Enormous deep green algal blooms result
from intense sunlight.
5
The final problem is that as human populations
rise, and water resources remain constant so that
recycling is encouraged. Will the French drink up
the Seine? New dams may be needed for various
population expansions. What happens when the
aquifer is empty? You wait for rain. Eventually,
everyone will feel competition for
water.Actinomycetes, microfungi and yeasts,
sulfate-reducing bacteria, sulfite-reducing
bacteria, iron-precipitating bacteria and finally
pathogens all contribute to the quality and taste
of drinking water. Water may best be surveyed
using gas chromatography.
6
Tropical countries short of water and having very
high evaporation rates may not benefit much from
sludge systems. To successfully recycle
contaminated water may require a biofilter as
used in Chile consisting of boulders, smaller
rocks, sawdust and a 20-40 cm soil layer with
earthworms (Eisenia andreis) at 5000-10000 worms
per m3. The water from this system at depth 1 cm
passes a UV lamp of 30 watts per m3/sec that
kills all bacteria. This small system can be
scaled up.
7
In Chatham county, North Carolina, USA,
wastewater is cleaned for reclamation and reuse
using , and a greenhouse containing. It not only
purifies water and reclaims nutrients, but also
reuses water, and therefore RECYCLES WATER.
Nutrients from the wastewater are captured to be
used later as fertilizer for plants.
8
Making soil-containing filters in North Carolina.
9
Biodegrader at work in Colombia.
10
Is bottled water safe ? Crypto by its small size
is causing us to become reeducated in clean water
technology. Look for a filter that will remove
particles that are less than or equal to 1 micron
in diameter. There are two types of these -
"absolute 1 micron" filters and "nominal 1
micron" filters. The absolute 1 micron filter
will more consistently remove Cryptosporidium
than a nominal filter. However, how long will a
filter last before cloging in such rigid
conditions?
11
Fertilization and ozonation. In other projects
with potable water, sediment cartridges are used
to catch dirt, sand, mineral or metal particles.
They are available in 20, 10, 5 or 1 micron
sizes. Lower micron ratings mean smaller particle
removal. Try 5 microns or less. Replace when the
filter plugs up or reaches the 3-4 month lifespan
or purchase a reusable cartridge. These are all
10 inch tall cartridges for standard canisters.
Flow is 3-4 gallons/minute. Material10 inch
pleated polyester.
12
Cyst-forming Protozoa have eluded chlorine as the
main disinfectant of civic drinking water for
over a century. Perhaps the pathogenic ameba
Entamoeba histolytica causes undectected low
levels of infection constantly, at least in some
countries. Cryptosporidium parvum on the other
hand has scored resounding epidemics. The most
dramatic failure of water supply protection in
Milwaukee, Wisconsin in the spring of 1993
allowed a diahrrea involving 400,000 people, 50
of whom died.
13
Cryptosporidium oocysts are currently found in
surface waters. Their incomplete removal by sand
filtration and their high resistance to
chlorinated disinfectants make possible
waterborne cryptosporidiosis outbreaks after
drinking treated water. Ozone is an alternative
to chlorine for final drinking water
disinfection, important as chlorine does not kill
protozoan cysts.Therapeutic and laboratory grade
ozonation systems utilizing the low frequency
(50/60Hz) corona discharge ozone production
process have dominated the field of Ultra Pure
Ozone Applications for the last 20 - 30 years.
14
Avoid being the victim. Cyclospora infection can
be prevented by avoiding water or food that may
be contaminated with feces. Uncooked fruits and
vegetables should be washed thoroughly before
eaten. Always thoroughly wash hands with soap and
water before handling food, after using the
toilet or changing diapers, after handling animal
stools (feces), and after gardening or other
direct contact with soil. Do not drink water
directly from streams, lakes, springs or swimming
pools. Boil water for 1 minute at a rolling boil
whenever you are unsure of the safety of the
water supply.
15
THE PARASITESThe taxonomy. The Kingdom
Archezoa Haeckel, 1894 contains 3 phyla one of
which is Metamonada Grassé, 1952. Giardia belongs
to the order Diplomonadida Wenyon, 1926 class
Trepomonadea Cavalier-Smith, 1993 of Metamonada.
The other 3 genera of parasites belong to Kingdom
Protozoa Goldfuss, 1818.Phylum Sporozoa Leukart,
1897 ( Apicomplexa Levine, 1970) contains the
class Coccidia Leukart, 1879 and the order
Eimeriida Léger, 1911, containing Cryptosporidium
and Cyclospora.
16
The sexual stage. The key to parasite survival
is of course the resistent cyst. Giardia is a
flagellate and Entamoeba an ameba that do not
have sexual cycles, and the others are
eimerians. The cyst is a life cycle stage, not
related to any sexual phase. Most Protozoa have a
haploid set of chromosomes which is to say that
they are haplonts. Upon the union of male
(microgamont) and female (macrogamonts) nuclei,
the karyosome (zygote) is doubled (2n) and
immediately reduces to half that is the haploid
number (n). The female gamont becomes the
macrogamete without division. Microgametes can be
many with 2-3 flagella.
17
Although the number of bodies like merozoites may
be different in stages Type1-3, the number of
chromosomes each has is presumably the same. The
macro- and microgametes fuse to form the
karyosome (zygote) that immediately reduces its
chromosome number as in 2n n n. This is
zygotic meiosis, sometimes called haploid
meiosis.
18
(No Transcript)
19
(No Transcript)
20
Symptoms may include intermittent diarrhea and
constipation, increased gas (flatulence), and
cramping abdominal pain. The abdomen may be
tender when touched, and the stool may contain
mucus and blood. The person may have a slight
fever. Between attacks, symptoms diminish to
recurring cramps and loose or very soft stools.
Wasting of the body (emaciation) and anemia are
common.
21
Four-nucleated cyst with rounded chromatin
bodies. Nothing more CLASSIC is found.
22
Giardia lamblia is the most common of these
parasites generally, although E. histolytica is
more frequent in some areas. These 2 important
parasites are omnipresent in many countries, and
much more frequent than Cryptosporidium parvum
and Cyclospora that occur episodically. A small
fraction of Giardia cysts can withstand a single
freeze-thaw cycle. They can survive for 2-3
months in water temperatures of less than 10/ C,
and at 21/ C, cysts have remained viable for
almost one month. Cysts are killed in 10 minutes
at a water temperature of 54? C.
23
Giardia is a common protozoan parasite of farm
animals, especially calves and lambs. Dogs are
often found infected cats less frequently, yet
pets are not a transmission problem. Wild animals
are often infected.Each year 4,600 persons with
giardiasis are estimated to be hospitalized in
the US. Hospitalized cases are primarily children
under 5 years of age, and dehydration is the most
frequent codiagnosis. A
potentially serious consequence is nutritional
insufficiency which may result in impaired growth
and development of infants and children. Other
reported associations with giardiasis in children
include malabsorption of iron, allergic
reactions, inflamation of the synovial
membranes of major joints.
24
Two trophozoites of Giardia lamblia, one of which
is in metaphase of mitosis, having about 14
chromosomes.
25
Cryptosporidium parvum Tyzzer, 1911.
Cryptosporidium belong to a group of protozoa
occurring in the dung of farm animals which can
be washed from agricultural land into nearby
rivers. It is normally spread through
contaminated water or contact with an infected
person - but unpasteurised milk and offal can
also carry cysts. Cryptosporidiosis is most
common in children between 1 and 5 years and is
often associated with farm visits, as when a
child has cuddled a lamb. The disease is known in
cattle, sheep, goats, dogs, cats and in birds.
Outbreaks also occur in children's nurseries.
Larger outbreaks are linked to contaminated water
in both the water supply and in swimming pools.
26
Cyclospora Ortega, Gilman Sterling, 1994 has
8-10 micron diameter about twice that of
Cryptosporidium parvum. Oocysts can be identified
in fecal samples by examination of wet mounts
under phase microscopy, use of modified acid-fast
stains (oocysts are variably acid-fast), or
demonstration of autofluorescence with UV
epifluorescence microscopy. However, these
procedures are not routine for most clinical
laboratories, and confirmation of the diagnosis
by an experienced reference laboratory is
recommended.
27
Cyst of Cyclospora
28
Although DNA sequencing as in the polymerase
chain reaction (PCR) is available for both
Cyclospora and Cryptosporidium, it is uncommon
and likely limited to reference laboratories. If
a laboratory has a fluorescent microscope,
autofluorescence as in green protein will prove
very useful, even though ancient staining
techniques also serve for identifying any
sporozoans.Demonstration of sporulation provides
definitive evidence for the diagnosis. Infection
with Cyclospora can be treated with a 7-day
course of oral trimethoprim (TMP)-sulfamethoxazole
(SMX) (for adults, TMP 160 mg plus SMX 800 mg
twice daily for children, TMP 5 mg/kg plus SMX
25 mg/kg twice daily).
29
Comparison of the 2 eimerian parasites