Diarrhea, caused by waterborne Entamoeba, Giardia, Cryptosporidium and Cyclospora Paul R. Earl Facultad de Ciencias Biológicas Universidad Autónoma de Nuevo León San Nicolás, NL 66451, Mexico Paul R. Earl

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.

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.

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.

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.

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 cm soil layer with earthworms (Eisenia andreis) at worms per m 3. The water from this system at depth 1 cm passes a UV lamp of 30 watts per m 3 /sec that kills all bacteria. This small system can be scaled up.

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.

Making soil-containing filters in North Carolina.

Biodegrader at work in Colombia.

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?

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. Material:10 inch pleated polyester.

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.

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 years.

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.

THE PARASITES The taxonomy. The Kingdom Archezoa Haeckel, 1894 contains 3 phyla one of which is Metamonada Grassé, 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, Phylum Sporozoa Leukart, 1897 (= Apicomplexa Levine, 1970) contains the class Coccidia Leukart, 1879 and the order Eimeriida Léger, 1911, containing Cryptosporidium and Cyclospora.

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.

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.

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.

Four-nucleated cyst with rounded chromatin bodies. Nothing more CLASSIC is found.

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.

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.

Two trophozoites of Giardia lamblia, one of which is in metaphase of mitosis, having about 14 chromosomes.

Cryptosporidium parvum Tyzzer, 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.

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.

Cyst of Cyclospora

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).

Comparison of the 2 eimerian parasites