metadata: authors: 0: author: Liese, Bernhard
1: author: Gratz, Norman
docna: 0: docna: The selection and use of pesticides in Bank
            financed public health projects
docty: Policy Research Working Paper
subtopic: Health Care Services Industry,Pest Management,Public Health Promotion,Hydrology,Cholera,Malaria,Communicable Diseases,Leprosy
teratopic: Health, Nutrition and Population
abstracts: cdata!: Vector, snail and rodent-borne diseases
            are responsible for a great deal of human morbidity and
            mortality in the tropical developing countries. Of the three
            methods for controlling tropical diseases, environmental,
            biological and chemical, pesticides are the best
            alternative. Whenever possible, however, these chemicals
            should be used in conjunction with environmental or
            biological methods and the appropriate drug or vaccine.
            Public health officials must be concerned that the compound
            chosen is safe for the user as well as inhabitants and
            domestic animals in the treated area. The method of control
            must also be appropriate for each targeted vector, because
            there are large biological differences among species. Some
            other considerations are that: (a) the chemical must be a
            narrow spectrum pesticide; (b) it should be effective in the
            proposed geographic area; (c) the target should be evaluated
            to check its resistance to a given chemical; and (d) the
            proposed pesticide must not pose a hazard to species that
            are not targeted.
repnme: repnme: The selection and use of pesticides in Bank
            financed public health projects
display_title: The selection and use of pesticides
            in Bank financed public health projects
listing_relative_url: /research/1988/06/700699/selection-use-pesticides-bank-financed-public-health-projects
topicv3: Water m1326522 137,Malaria m1327042 1420,Public Health m1327519 635,Pesticides m1504403 2914,Health m1504661 3480
publishtoextweb_dt: 2010-07-01T00:00:00Z
historic_topic: Health, Nutrition and Population
origu: Policy Plan & Prog Review Dept
no_of_pages: 23
model_extractions: # Polky anning, and Romrch

Populbtlon, Health, and Nutrition Three methods are available for controlling - vector-borne tropical diseases environmental, biological, and chemical. Environmental control to permanently-alter the conditions that allow vectors to breed and develop is the preferred method, but it is not always feasible. Biological control is species-specific and may only be effective under narrow ecological circumstances.

For control of most diseases, therefore, pesticides are the only altemative. Whenever possible, these chemicals should be used along with environmental or biological methods and the appropriate drug or vaccine. This will cut costs, reduce contamination from pesticides, and lower the possibility of resistance to the pesticide.

Public health officials must be concerned that the compound chosen is safe for the user as well as for inhabitants and domestic animals in the treated area. The method of control must be appropriate for each targeted vector, because there are wide biological differences among species.

Some further considerations in the selection of a pesticide for a public health program to control a particular vector of disease are:

* The chemical must be a narrow spectrum pesticide.

* It should be effective in the proposed geographic area.

* The target vector should be evaluated to determine if it is resistant to a given chemical.

> * The proposed pesticide must not pose a hazard to species that are not targeted.

This paper is a product of the Population, Health, and Nutrition Division, Population and Human Resources Department. Copies are available free from the World Bank, 1818 H Street NW, Washington, DC 20433. Please contact Carol Knorr, room S6137, extension 33611.

The PPR Working Paper Series disseminates the findings of work under way in the Bank's Policy, Planning, and Research Complex. An objective of the series is to get these findings out quickly, even if presentations are less than fully polished. The findings. interpretations, and conclusions in these papers do not necessarily represent official policy of the Bank.

Copyright (3 1988 by the International Bank for R>construction and Development/The World Bank
# ¶lE SE9EUCZ AND USE OF _E1I_ IN PUBLIC HEAfLH Eff3E1 IN BA1 FDWiCED

1. Vector, snail and rodent-borne disea are responsible for a great deal of iman nxbidity and nmrtality in the trpical deacpirq countries. It is estimted that every year there are scme 9' million new ecas of malaria and the incidence of other parasitic diseases, such as sc±iisbceiasis, leishaniasis, Chagas' diseas, sleepiig siccness, hocoerciasis and filariasis, totals many million. In addition to the parasitic diseases, the incidence of arboviruses is tens of millions of cases anmaally, includirq millions of cases of dengue, hundreds of thousarxs of Cas of dengue _hagic_ fever and hundreds of cases of yellow fever. the greatest transmission of the vector-borne diseases occurs in rural areas, and the burden caused by these diseases, especially malaria, Chagas' disease, sdiistosoriasis and hnchocerciasis, can have a significant inpact on develcrpent projects in endemic areas.

2. Increases in vector breeding and higher disease incidence can result from water devalcpmnt projects when inadequate cosideration has been given to their public health and environnental impact. The use of pesticides is then required for vector cotrol - particularly for mosquitoes and snails. Another cause for increased vector densities is rapid and often unplanned urban graith in large tropical cities where envircwumental sanitaticn is frequently poor. Vector densities can be high enough to mainrtain disease transmdssion and disturb the lives of the inhabitants.
2 Consequently, inst of these cities have vector control programs which are lYMvily dependent on the use of pesticides.

3. any cuntitries have programs for the control of one or more of these diseases, depernding on their imrportance and prevalence in the country, and a significant prcportion of the budgets is allocated to national control program. Scme of thes- dir. ases can be controlled or cured by ch~therapeutic drugs or prevented by cherprophylaxis or vaccination. However, for many diseases there are no vaccines or drugs suitable for mass or evesi individual treatment. Where no such cure or treatment exists, the most comma strategy is control of the disease vector. In some regions, particularly urban areas, control program target vectors not because of the potential for disease but because of the annoyance and nuisance they cause people. Vector control may snmetimes also be the most effective cont ol Methodology both in terms of cost and of reduction of disease. A. The selection of vector control methods 4. Once a vector control program has been decided upon, the method of control needs to be selected. There are three basic methods: enviroenental, biological and chemical control, or a ocmbination thereof. Emriromnental ocntrol is the. preferred method to achieve permnanent control. It seeks to alter the corditions allowing the vectors to breed and develcp, and thereby avoids or reduces the xe- for oontinued pesticide use. Unfortunately envir,nnental control is not feasible against several - - imnortant species of vectors, such as misquitoes whose breeding occurs over very large areas, or vector species - for malaria and arboviruses - whose larval habitats are numerous, small and scattered. Equally funds may not be available to eliminate the polluted - mainly sewage water - habitats
3 where many urban nmsquito species breed. Ewrrironnental control of tsetse flies by clearinr bush or killing host game animals is possible and has been dome but is ecologically undesirable. Control of the triatcminae vectors of Chagas' disease can be ach*leved by repairing ard improving dwellings with walls and roofs that discuarage vector breeding. 5. The use of biological control agents, such as parasites, predators or pathogens, is ancther potential alternative for vector control. But they are usually highly species specific ard may only be effeative urder narrow ecological cir1austanoes. Some recently developed bacterial toxins can be applied as biological larvicides against mosquitoes and blackflies providing the vector species is susceptible to the toxin and the ecological conditions appropriate for application. Consi '.e success has been cbtained through the use of Bacillus thuriMieirrs kF'-14 in the UNDP/World Bank/WHO Onchocerciasis Cbntrol Prograwme in West Africa. Another example of biological control under investigation is the use of non-vector snail species which prey upon or ccnpetitively displace vector species. Active research for additional agents is beirq pursued by the UNDP/World Bank/WHO Special Progranme for Fesearch and Training in Trcpical Diseases. Among other groups, hover, only a few, promising candidates are presently available. Studies are still underway on same plant molluscicides for use against the snail hosts of schistoscmiasis, but in cperational use they have no particular advantage over chemical molluscicides. Because the great expansion in irrigated areas has actually favored the intensification of schistoscniasis transmission in several endemic areas, control programs using a chemotherapeutic agent in combination with molluscicides are of growing imTportance. The introduction of certain fish species into vector
4 erwilranwts has also proven a satisfactory method of biological control in

-ree instrxms.

6. Intensive efforts are being made to develcp andi use new biological and enmrontontal ds as alternatives to or cmpler entary with dhemical pesticides. In certain case those efforts have met with considerable sucxess; as an example, simple inexpensive traps have been develcped for use against tsetse fly vectors of African sleeping sickness, particularly riverine species, and are cauing into wide use as an effective, c.munity-i plealted alternative to the applicaticn of pesticides. Because there are no biological or envira_ental methods or drug therapy presently available or feasible for the control of many other diseases, there is little doubt that pesticides will be required for the foreseeable future in the majority of vector control programe. Nevertheless, whenever possible the use of pesticides should be Integrated with enviromental or biological methods and, if possible, with a curative or prophylactic drug or vaccine. This will assist in cost reducticn, reduce the enwircrmental contamination from pesticides and also assist in lcwering the rate at which resistance will develcp against the pesticides used. Wiere such itation is not feasible or, when epidemic out}reaks _occur_ and control of the vector pcpulaticns is urgent, it may often be necessary to rely entirely on the applicaticn of pesticides. B. The use of pesticides in public health 7. The manner in which pesticides are used and applied for the control of disease vectors differs very sharply from their usage against pests in agriculture. Most vectors of hbman disease are closely associated with man and his imediate envirunent, therefore pesticides for vector
5 c1trol are _freqmntly_ appied in or arzu bman dwllings. nz*thermre, safety of ie cides used in piblic helth is of pwraunt iprtaro. Pesticide aopn{ds destined for use in piblic health progrwu mist be dmrIutzably safe for use both by the spraymen applyirn the oupcrds and for the inabitants and dcmeatic animals of the treated areas. 8. An example of suci a xqxiu is =,which despite pcpilar caxezi has an emllent safety record in t of its low aaute and ctmiic taxicity to man. mide mOr has had advere affects cn the re icn of sme bird and fish species when used as an agrialtural pesticide, there is ro envirct'enrtal crntarination when used as an ir_oor residual **sIiy** applied ty trained spray perscmael in malaria contral progrark. Nor is there any indication of any adverse aoate or dhrronic affect on the hundreds of miuicos of peole whose homes wre sprayed with mOr in the course of the glcbal malaria eradication program or the subsequent widespread malaria oam*rol prograns carried out by many national ministries of health. 1 Therefore, DDr remains the pesticide of dhoice for malaria control. The min reason for the reduction in DDT usage is widespread pesticide resistance in many malaria-vactor mosquito species exposed to the ccurqnd over many years.

9. TW inportant elements in the the selection of pesticides are the bionmics of the target vector s and the eWideuio1ogy of the The cnxtrol method or material mist be irdividually selected for eadh vector species as there are wida biological variances amng species. As an example, anopgline mcisqito v cts of malaria which are active WIH, (1971), "The Place of DOD in Operations aanst Malaria and Other Vector-borne Diseases," Official Records, World Health organization, Document No. 190:176-182, Geneva.
6 primarily iridoors can be inst effectively and ecncmical1y ccntrolled by aplying residual pesticides indoors. Hawever, those anpheli. species 'which are active primarily autdoors are not effectively controlled by indoor treatments and mnust be controlled by treatment at their larval habitats or by ultra-low volum -Ast or fogging aipplications. Ae a the urban vector of yellow fe vr in Africa and the Amercas and of dengue and denmue esixrrhagic fever in South Asia, the Western Pacific and the Amricas breeds primarily in a multitude of fresh watbrh cuitaJners such as drums, pots and jars storing drking water, old tires, eapty tin cans etc. optimal cotrol of this secies can be adcieved by provision of piped drinxing water and envircrm.ntal sanitation practices including efficient disposal of waterholding waste containers or by application of larvicides (with a very low wanmalian toxicity) to larger cotainers such as druns holding drinking water which can not readily be disposed of or sealed. Dring epidemic ootbreaks of _. ypti-borne disease in urban areas, the most rapid and efficient, if only temporary, control is thrcugh the application of pesticidal space sprays or fogs by aircraft, vehicle or manborne dispersal equiPmient as well as envirocrental sanitation methods to oontrol adult female mosquitoes likely to be carTying virus. In every case the apprcFriate methodology muist be determined based _on_ a clear understarxing of the bioinomics of the particular vector species. 10. Certain vectors and pests live primarily on man; aumiu these are head, body and pubic lice, scabies mites and some species of ticks as well as a number of species of fleas. Body lice can be vectors of epidemic typhus and epidemic relapsing fever. These ectcparasites, particularly lice and mites, mist be controlled by the application of pesticidal dusts,
**7**

lotions or emulsicns directly to man and it is essential that these pesticides and their formulations be of a minimal tocicity so as to cause no hazard to man.

11. In agriculture, vector control need not be total, as lonq as the degree of damage caused by the residmua pcpulation is minimal and of 1 v ecmncic significance. Ha,ever, vector control for human dises or pests reqns tartjeting for the rtial level of effective cotrol of the vector poptlation. If the achieved level of control continues to allow tra issicn of disease, this wjld not generally be acceptable, especially if thre is sae bman mortality. In develcped ccimtries where vector ccutol - especially in urban areas - is mainly to control pests rather than disease, any continued irritaticn after treatment frcm mosquito bites, bed bugs and cocdroaches wi.P . _n,t_ easily be tolerated.

C. The selecticn _blichealth of Desticides for us 12. The selecticn of a pesticide for a public health program to control a particular vector of disease mist consider the foll-win:

- (a) The efficacy of the available ooupcnuds against the target

- I -vector in the proposed geographical area. Selecticn should only be made of a ccmpound with a known efficiency against the target vector species. 2 Field trials may be necessary if the ecology in the proposed site differs frim other areas where the pesticide has been used or if it has not previosly been used against the particular species or vector.

> 2WHO, (1984), "Chemical Methods for the Comtrol of Arthrpodl Vectors and Pests of Public Health IDortance," World Health Organization, Geneva
8 (b) lhs s tibility of the vector pcilatioa in the target arve to the prcpsed p-sticide. The target vector ne to be evaluated to determine if resistance has already develmed to the prcpoed c x d. Res my hMe oxred by prior ecposure to the prcqosed coqxxvid or cars-resistance to a related o. The prcposed ocqxcrd may already be ineffective for vector control in the target area because of _prevics_ aWlications in _agricultural_ proram. Where resistance already exists to a given dcemical group, no use shcx ld be mde of ccuIpomfs ,whidh are closely related chemically or cross-resistance might occur.

**(c)** The safety of pecple exsed to the prcuwosed pesticide. The tcodcity of the given corpound should be low ena4gh to ensue the safety of the spray persorwel applying it and of the inhabitants of the houses or area in whidh it is being applied. Oral, dermal and inhalation toxicity, as well as bo&h acute and dhronic toxicity must be taken into acomnt. lb. latter my be especially iqportant for the spray persmnnel Who are under prolcnged exposure to the _cqmpcund,_ frequently under climatic conditians Whidh _disccurage_ the use of protective clothing. Adequate training of spray persannel and, if necessaryf, provisimn of protective e*qipment (clothes, hats, masks) dhould be c **nsidered.** Reference should be **m** to the World Hbalth Organization classification of pesticide oral and drma
9 toaicities, whidh dalso cutlines the toxicity and hazard presented by the conaentration of the active i dient in ready-to-use formulaticns.

(d) The envircrmental ibact of the proposed pesticide. (i) If the ccrpound is to be isal in an aquatic envirAnPent, (i.e., for the control of nmsquito or blackfly larvae) or in a manner in which it may cIntaminate the aquatic environment (e.g., for the control of riverine tsetse fly species), then the proposed pesticide ur, . -e safe encuh to pose no hazard to non-target aquatic organdisms especially fish and nan-target aquatic invertbbrates. Hazard to aquatic organisms is a function of materials, innate todicity to each species, the concentration of the materiAl in the water and duration of exposure. Each of these factors can be controlled to minimize environmental i mact. Fbr example, use of controlled-release forjvlaticiis can scanetims be used to provide long-term cxntrol without an initial high concentration which may be hazardcas to non target species. They also provide persistence at point or action without reocurse to persistent diemicals. (ii) If the pesticide is to be applied as a space spray for the control of flying insects, such as mosquitoes or house flies, applications should ,.t be made in areas where hcneybees can be affected. (iii) If the pesticide is to be applied for the ccntrol of rodents, preference should be given to the use
10 of the o ,xurxds of low toxicity to ron-to the prcposed acrdut. Pesistance may have Occutred by target mamlals. R~nticide whm used in h}u should be applied in bait boxes to prevent easy aocess by human or dcuestic animalS.

- (e) The selecticn of narrow spectnu pesticides. Providing that they are as effective against the target vectors as wide spectrun pesticides, every effort shculd be made to select narro spectrum pesticides thereby minimizing any effect on non-target species. Careful control of dosage may improve specificity of certain products, particularly in aquatic ervironments.

- (f) The proposed pesticide should be different and preferably not closely related to pesticides used in the target area's agricultural pest control.

(g) Nblluscicides must be applied to water ways or collections if they are to control the snail intermediate hosts of asis. Only a small number are now ocmmercially available and their ulse shculd be carefully supervised. D. Procurement of 33esticide. 13. The invitation to bid and tender documents should use the accepted generic name or names _cZ_ the active material or materials thereby enablin suppliers - who may market the identical ingredient under one or more trade names - to offer cc petitive bids. The tender documents should state the O specification number; the concentration of the active 3 For a more detailed outline of procedures see _OPN U.l01._
11 ingredient and in same casms the content of specific iscumers<sup>4</sup> ; the inspection and sampling requirements and procedures to ensure comliance with pmcrdaser's spesd .ications, upon ocmpletion of the order but prior to acceptance, the name of the inspection agent and/or laboratory; and any special requiremwnts the purchaser might have (e.g., long team storage). Specification of storage life is particularly inportant in the case of products (e.g., Malathion) which may yield breakdbwn products considerably more hazardaus than t-he parent material. In any case products which have been stored in hot or humid conditions for lon periods should be analyzed before use.

14. For fornulated materials, the specification shculd define the critical characteristics which may affect the performance of the pesticide: for example, for an emalsifiable concentrate: the solvents, emnlsifiers, and surfactants; for a water-dispersible powder: nominal content, tolerance permitted, particle size, suspensibility, acidity or alkalinity; and for a dust or suspension: particle size and nminal content. Rodenticides should be formulated with warnin colorants or dyes which will persist for the anticipated storage period, handlixlg conditions and any further preparation of the product.

15. The specification should indicate an,y special features of packagin (box or drum containers) and labeling which are nraessary for product protection during handling and storage to ensure effective use. It shculd require packaging and labeling to be consistent with accepted standards for each cuntry and indicate the language or languages which the 4In the case of HCH, only the pure gaa iscmer (Lindane) sbhuld be used.
12 label is to bear. Package sizes shonld be selected to avoid the need to store qpen, partially used padages. 16. The omntairers shcld be labeled in the courtry's language, with a clear warnirg of the contents hazards, instnraticras for its safe handling and, where rite, mrgeny infcxmation in the event of accidentabcontact or spill. Mininum cauticnary notioes are included in the WD specifications. Mbre detailed rec muerdaticns on the safe handling of pesticides, the protection of cperators, the detection of exposure, and the treatment of intoxication will be found in the sixteenth report of the WHD Expert ocumittee on icides and in the third report of the MMD Expert omnittee on Vector Biology and Oontrol. 17. Same of the lMD specifications require reference materials for stailardizing analytical procedures for scme pesticides (e.g., bendiocaIb, brLeCmACos, chlorpyrifos, Dr, deltamethrin, diazinon, didhlorvos, fenitrhion, gamma-HCH, malathion, prcopmw and temephos). ¶he MID supplies free of charge reference samples to official analytical and quality control laboratories working in the public health field.

18. Wberever possible ccopetitive tenders shoAld be sought for the supply of pesticides. If there is cnly cne manufacturer for a product that is tedhmically superior to other commrcial products or the cnly effective cne in oontrolling a particular vector, then a direct purdhase may be resorted to. In sudch case irnuiries should be made to determine the prices paid by other reoent purndasers of the product in order to ascertain wether the price being quoted is a fair one, taking accunt of the quantity being ordered and delivery reqirane nts.
13 19. _ITrcl purcham_ can be nss if only a mall Iquantity of the product is required and a competitive bidding process wculd not be feasible. HFwever, qaotatiom shKuld be cdtained from at least three different syppliers and the udnimn labeling reqpdre ents mentioned above bhould still aWly. The limited shelf life of certain active ingredients and f'omulaticins shold be kipt in mind and an effort nade to dstearine the date of minufacture or at least the date pesticide was ordered or received by the .uplier.
Pesticides Ued in Public HEalth Hazard Classifictia & Majr Uses

|Pesticide<br>gzm4|WH Hazard<br>classificutigp|Major<br>uml|u<br>used2|
|---|---|---|---|
|DM<br>D|:<br>I|mos fls<br>lic|res<br>dst<br>lar|
|g azu-HCH|II|mis tri<br>lic<br>fls|res<br>dt<br>rnm|
|elosulfan|3I|tue|rem|
|Azauethis|mIII|hfl|baits|
|:ra1~ths|mIII|fl hfl|res lar|
|d<br>mozIom|mno ac haz <sup>3</sup>|bkf|lar|
|chlorpyrifos|II|mm cir|lar|
|chloxpyrifcs-mtyl|II|mm|lar|
|diazinon|II|dckr hfl<br>fls|dst|
|didhlorvos|Ib|moo hf1|fu|
|din~ethoate|cI|hfl|rem|
|fenchlorphos|II|hfl|res|
|fenitrothiac|II|=a<br>fls|res<br>spa<br>dst|
|fenthicn im||mb|lar|
|iodofWI|no ac haz|dcr<br>fls<br>bdb lic|dot|
|malathicun||mm bdb lic<br>tri|re<br>qa<br>lot|
|---|---|---|---|
|raled|D:||spa|
|phm|II|bkf|lar|
|piri<br>sm-uthyl|m|m,<br>fl sdcrbdb|res spa dst|
|}rZ<br>Cetulm|lb|dlr hfl|rem|
|tamcM|no ac haz|_m:w_bkf lic|lar dot|
|builiocarb|II|_msm_tri<br>hft 1se|sa<br>dAnt|
|cabaryl|II|_mom_f3s lic|rm<br>dt|
|diao~0cmr|II|Mb cwr|rs|
|r<br>2pr|II|_Ms_fis<br>dk|rag dit<br>_ds_|
|Pyrtroids||||
|allethrin|T|mos hfl|spa|
|b)icallethrinl|II|msm hf<br>lic|Wpa lot|
|biomwthrin|no ac haz|mm|_rem_spa|
|aypinrnwthrin|no ac ahz|_soR_hfl|rem|
|deltaU~rin|no ac haz|mom te<br>hfflM|rm<br>pa ]a|
|fenralerate|I3|hfl|res|
|perzmthrin|no ac haz|_mom_bkf tu<br>hf1|em spa 3a|
|Eotrin|no ac haz|mwehfl|rum spa|
|plpercnyl<br>bibtodde|no ac haz|mso hfl|wpa|
|remtbrin|in|_mom_hfl|ua|
|tetrammthrln|no ac haz|hfl|spa|
> mnet crkh aU diflubaezuron no ac haz ums la rio ac baz ms la 1 uDeiucdtoes, t_u-tsetse flies, hfl-hxse flies, dkrocia-c-, fl-fleas, lio-lice, bhdbbedbqs, bkf=bIadkflies, tri=triaminae 2 #residual, lar-larvicide, dtdusts, panspace says, uafgaLnt,

loblotimr 3 no ac hmvzudAlkely to present actate hazard in rmrml use.

A. _1T7_ MM periodically revises and reissues its "Oificatic of t&bicides y H r." Ii lists tecnical products by their geneic rames, tabilatng them in categories _raning frna_ "Eisely Hazardous" to UnlikEly to preset ac:ute hazard in rmml use. Guidance is given an use of the tables to aasess the hazard of clatis. Materials listed in CategaLies la Extxwasly Hazardous or Ib Highly Hazardus are unsuitable for rml use in public health prograns. B. qhs 1,capuds cm didclrvos, fenthion and prpel (ND Hazard Classification lb - hily hazardou) are unsuitable for use other than by hily skilled an trained personnl under strict riprvisicn. C. The restricticra for pesicide use in agriculture (OPN 11.01) also aply with cm =jar mr isMicn. the pesticide of dbioe in
I nmlaria cntrol where there is no resistanos to it. Its use as a residual indoor insecticide causes no envixu ntal contamination and does not ccmstitute a health risk.

D. A current copy of the WM) hazard classification and a list of specific reference publicaticrs (additional rescnur list for OPN 11.04) is available for referene in the Sectoral Library.

I
~~~2

# Mdjtimia Resouro

The followiug resoures may be useful in obtainin more specific infonnation.

A guide to rodenticides and their use &3ainst ccaueisal species of rodents is available frc the World Health Organizaticn, (Broaks, J.E. and Rmm, F.P., 1979a). The U.S.A. Eimi umnal Protecticn Ager-Y has extensive guidelines for the allowable erjvircowntal hazard of ucet pesticide.

Pesticide chemical reference materials Same of the WHO specifications require reference materials (e.g., bendiocarb, brcmophcs, chlorpyrifos, DDT, deltamethrin, diazinon, dichlorvos, fenitrothion, gamma-HCH, malathion, prq=oxur and tmephos). The WD supplies free-of-ctarge reference samples for stardardizing analytical prXcdLAUres for scme pesticides to official analytical and quality control laboratories working in the public health field. (Paquest sanples frcm Pesticides Developmnt and Safe Use, Vector Biology and Control Division, World Hbalth organization, 1231 Geneva 27, Switzerland.) Other laboratories can dotain analytical standards either directly froa the manufacturers or frm institutions sudci as the National Trysical Laboratory, Teddinton, Middlesex, ¶Wl 10IW, EnglaTid or frm the U.S. Ervircnmetal Protection Agency, Pesticide & Irsecticide chemical
Peqository, ail Statin MaS, E.eardi Triange Park, Nbth Carolira 27711, USA.

MM, (1986a) "WM Expert Omittes on Malaria," 18th RPort, Techi. lhport No. 735, World Health **G** eva.rganizantio, WD, (1985), "Ihe Cmtrol of S o niasis," IRqt of a VW Expert Cnwmittee, Tech. Report No. 728, World Health Organization, Geneva.

OCP, (1984) flTIm Years of Qr r maiasi.s Cmtrol in West Africa," Report No. OCP/84.3, World Health Organizaticn,, Geneva. Smith, A. and Gratz, N.G., (1984), "Urban vector arid rodent cMntrol services," WHD unpublished doctment No. VBC/84.4, World Health Onization, TER, (1982), "Report of an Infornml Yesting on Glosina Trapping," Report No. TIR/¶MY(AF)/GP/Brazz/82.3, World Health Orgaization, Geneva.
WD, (1971), "The Place of DMr in Operation against MNlaria and Other Ver.law-borne Diseases," Official Records, World Hbalth organizaticn, DOcument No. 190:176-182, Gbneva.

MD, (1986b), "The WM Reccmue3ide Classification of Peticides by Hazard and GUidelinesJto Classification 1986-87," Document No. VBC/86.1 Rev. 1, World Health organization, Geneva.

BrOOk3, J.E. and F.P. Rowe, (1979), "ommm-sal Rodent Ccmtrol," Document No. WH/VBC/79.726, World Health organdzation, Geneva.

World Bank, (1985), '"Qldelines for the Selection and Use of Pesicides in Bank FinaWed Project.s and Their Procurment When Finawx ed by the Bank," OFN ll.O1.A - Agriculture, World Bank, Washirgtmn D.C.

WMD, (1986c), "Specificaticns for Pesticides Used in Public Health,"I Sixth edition, World Health Organizaticn, Geneva.

WID, (1967), "Safe Use of Pesticides in Public Health," 16th Report of the lMD Expert Cmuuittee on Irnecticides, Tech. Report. No. 356, World Health Organization, Geneva. WHD, (1979b), "Safe Use of Pesticides," 3rd Report of the MMD EXpert Qmnittee on Vector Biology arld Qitr0l, Tech. Report. No. 634, World Health Organization, Gbreva.
# PPR Working Paper Series

||Title|Autho|Date|Contact|
|---|---|---|---|---|
|WPS1|Imports<br>Under a Foreign Exchange<br>Constraint|Cristian Moran|March 1988|C. Hambidge<br>61539|
|WPS2|Issues in Adjustment<br>Lending|Vinod Thomas|March 1988|C. Hambidge<br>61539|
|WPS3|CGE Models for the Analysis of Trade<br>Policy In Developing<br>Countries|Jaime de Melo|March 1988|C. Hambidge<br>61539|
|WPS4|Inflationary<br>Rigidities and<br>Stabilization<br>Policies|Miguel A. Kiguel<br>Nissan Livlatan|April 1988|M. Kiguel<br>61761|
|WPS5|Comparisons<br>of Real Output in<br>Manufacturing|Angus Maddison<br>Bart van Ark|April 1988|E. Zamora<br>33706|
|WPS6|Farm-Nonfarm<br>Linkages in Rurai Sub-<br>Saharan Africa|Steven Haggblade<br>Peter B. Hazell<br>James Brown|April 1988|C. Spooner<br>37570|
|WPS7|Institutional<br>Analysis of Credit<br>Cooperatives|Avishay Braverman<br>J. Luis Guasch|April 1988|C. Spooner<br>37570|
|WPS8|Prospects for Equitable<br>Growth in<br>Rural Sub-Saharan<br>Africa|Steven Haggblade<br>Peter B. Hazell|April 1988|C. Spooner<br>37570|
|WPS9|Can We Return to Rapid Growth?|Andrea Boltho|June 1988|J. Israel<br>31285|
|WPS1O|Optimal Export Taxes for Exporters<br>of Perennial Crops|Mudassar Imran<br>Ron Duncan|June 1988|A. Kitson-Walte<br>33712|
|WPSII|The Selection and Use of Pesticides<br>In Bank Financed Public Health||||
||Projects|Bernhard Liese<br>Norman Gratz|June 1988|C. Knorr<br>33611|