Planting the Prevention of Schistosomiasis

8/3/2019 Planting the Prevention of Schistosomiasis

1/3

0% PLANTING THE PREVENTIONOF SCHISTOSOMIASIS

F r decades, Zimbabweansused the leaves, roots, andberries of the plant they calledgopo (Ended) to make floorpolish and medicine. Little didthey know that the berries ofthis climber shrub, scientificallyknown as Phytolaccadodecandra, might one dayhelp to control schistosomiasisdisease in their country.In 1364, a scientist in northernEthiopia discovered that when tinyamounts of dried Endod berries werecrushed and mixed with water, asoapy foam resulted. The solutionkilled the freshwater snails, which hostthe schistosomal parasites, within24 hours.Dr Aklilu Lemmas discovery andconsequent international research arepotential breakthroughs for countries

like Zimbabwe struggling to combatthis water-borne disease.

16

Researchers at the Ministry of have negative effects on physical andHealths Blair Research Laboratory in school performance in infestedHarare are working in partnership children. In its most severe form,with IDRC to study whether they can schistosomiasis can result in paralysisand death.ncorporate Endod treatment intocurrent, community-basedschistosomiasis control programs inZimbabwes Primary Health Caresystem. If put into place, theseprograms will be the fast of their kindin any affected region of the world.Parasites living from host snails arethe cause of schistosomiasis. Whenhumans come into contact withcontaminated water the parasites,scientifically known as Schistosomcercarie, penetrate the skin. Theseparasites then develop into worms thatpass into the blood vessels of theintestines or bladder.Mature worms live for 4 or 5 years,producing up to 300 eggs per day andscientist3 say the more eggs in thebody, the more severe the infection.Blood in urine and stool, diarrhea,fatigue, fever, malnutrition, anddecreased immunity are oftensymptoms of schistosomiasis. Thedisease has recently been found to

Two million of Zimbabwespopulation of 9 million are affected bythe disease; a great many others are atrisk. After malaria, schistosomiasis isthe most common parasitic infection inZimbabwe.Schistosomiasis has its highestprevalence in &lo year oldschoolchildren who frequently comeinto contact with contaminated water.Open water bodies used for bathing,cooking, laundry, and irrigation -especially in rural areas -serve asbreeding grounds for both the snailsand the parasites they house.Since mid-1989, scientists at the BlairResearch Laboratory have beencultivating various Endod strains totest which plants will control thedisease most effectively. JerryNdamba, the project leader of theEndod studies at the Blair laboratory,says future Endod use could


2/3

dramatically reduce the incidence ofscbistosomiasis. It will also, he adds,be a more viable and cost-effectivemethod for Zimbabwe to combat thedisease.Ended treatment encouragesself-initiatives while lessening ourdependence on westerntechnologies, he says. Thesetechnologies are normally 0t of thereach of most developing countries.The wild plant Endod could replacemore expensive synthetic ways ofkilling snails, scientifically known asmolluscicides. The most popular ofthese synthetic treatments is aniclosamide ethanolamine salt, calledBayluscide. Bayluscide is currentlythe only snail-killing compoundrecommended for use by the WorldHealth Organitation (WHO). But itscost, US$27,000 per tonne, makes ittoo expensive for large-scale se byZimbabwes Ministry of Health.As an alternative, the Blair ResearchLaboratory is experimenting withdifferent strains of Ended in 9 variousregions of Zimbabwe looking atdifferent altitudes, climates, soil types,and precipitation levels. Types ofEndod include the Ethiopian strain,E-44, and Zimbabwean strains ofEndod grown in the south (Masvingo),the north and the eastern highlands(Old Mutare).

The team is currently determiningthe conditions under which the strainsgrow best To date, indications are thatthe E-44 strain produces more berriesthan the local strains, growing bestwhen fertilized with manure andwatered regularly.Studies on E-44 concluded that itsberries were most potent to snailswhen picked at the green, unripestage and then air-dried in the shade.The dried berries can then be groundto a fine partide and mixed with waterto achieve the desired concentration.The solution is stored for 24 hours atroom temperature with occasionalstirring. Later, the mixture is filteredthrough a cotton cloth. The product isfinally homogenised and stored atroom temperature. A 100% mortalityrate occurs when snails carrying theschistosomal parasites are immersed inEnded-treated water at one part permillion for 24 hours.After application to the water, Endoddoes not remain or build up in theenvironment like some of the toxicmolluscicides. Indeed, before theEnded molluscicide was used incommunity trials, Canadianlaboratories, under the coordination ofCarleton University, evaluated itstoxicity. Despite its problems as asevere eye irritan4 Endod was foundto be no more toxic than currentlyrecommended molluscicides. Indeed,tests have shown that use of Endodcould be safer than genotoxicniclosamides like Bayluscide.

Changing habits, like refraining from wa.shing in open water bodies, havehelped in the thefight against the disease.

Idmratoty tats haveproven thepotency of the Ended bt?ny in killingthe snails that carp schistosomiasis.Earlier studies on End&senvironmental effects revealed that ithad little impact on plants andanimals, with the exception of someffih, aquatic leeches, and insect larvae.The indigenous plant that grows inZimbabwes endemic areas may allowcommunities to take over snail controlonce training is given, according toNdamba. ?he treatment is easy toprepare using local tools.Ended research has forged scientificlinks and fostered the belief thataffected countries have the resourceand technology to solve their ownproblems, Mr Ndamba says.communities Involved in ControlIf put into place, Ended treatmentwill allow Zimbabwes Ministry ofHealth to involve affectedcommunities in all levels ofschistosomiasis control. With fundingfrom IDRC, Blairs research team hasalready designed and introduced anintegrated, community self-helpcontrol program since 1985.The rural communities of Madziwa(32,000 people) and Bush (8,000) inthe countrys northeast region aretesting-grounds for the control

programs that include fourcomponents: self-help water and

17


3/3

sanitation projects, health education,chemotherapy treatment ofschoolchildren through the drugpraziquanwl, and focused antisnailprograms.The fact that 10 year old SimbarasheChagadama can cite the causes andsymptoms of scbistosomiasis, learnedfrom his brother in Form Three ofsecondary school, is a sign that thehealth education campaigns haveraised awareness of the diseasethroughout the community. Thecampaigns involve classes, drama, andsong comp3itions on schistosomiasiscon&l. -Now entering ts second phase from1330 to 192, the four components ofthe oroiect will be evaluated bvscie%ts at the Blair labonto&. Endodtreatment will allow the final segment,snail control, to be broadened toinclude community members.Research is also underway in Canadaand the USA to determine whetherEndod treatment can be used to killZebra mussels currently cloggingCanadas Great Lakes drainagesystems, illustrating that technologytransfers can flow both ways betweenthe1 North and South. The plant thatm=Y save schistosomiasis-afflictedcountries could also solve one ofCanadas major water problems.Deborah Carter in Harare, Zimbabwe

Jerry NdambaBlair Research Laboratory(Ministry of Health)Josiah Tongogara/Mazoe StreetPO Box 8105Causeway, HarareZimbabweFax OlC-263-4-792480

THE MAN-MADE SIDEOF NATURAL DISASTER

Fifteenears ago, 23,000Guatemalans died, more than100,000 were injured and closeto a million were left homeless- all in less than one minute.The force of one of the largestearthquakes ever in this small,poor Central American countrydevastated the population andleft more than a billion dollarsin damage.

A similar quake in Nicaragua in 1972destroyed most of thecapital city,another caused havoc in El Salvador in1985, and Hurricane joan wiped outhomes and lives on the east coast ofNicaragua in 1988.Like the wars that have put thisregion in the headlines, the sixcountries of Central America seem tohave more than their share of naturaldisasters.

Earthquakes, volcanoes, droughts,floods, rorrential rains, mudslides, andhurricanes occur here with afrequency unheard of in most otherparts of the world.But the problems of Central Americaare not solely the fate of nature. Infact, according to Jose Luis Gandara,who headed a research team lookingat Guatemalas natural disasters, thedisasters are not natural, but the resultof natural phenomena in vulnerableplaces.Proof of this point is the fact that theearthquake tint bit the majorAmerican city of San Francisco in 1989resulted in fewer than 100 deaths,whereas a similar quake in CentralAmerica would likely have leftthousands dead. In Central America,the low level of economicdiversification, concentratedpopulations n several high-risk zones,

Documents

Planting the Prevention of Schistosomiasis