aedesaegypti larval habitats in surinam

8/3/2019 Aedesaegypti Larval Habitats in Surinam

1/9

AEDESAEGYPTI LARVAL HABITATS IN SURINAM'~*Milton E. Tinker, Ph. D.3

Roof gutters can provide a good refuge for Aedes aegylarvae. This article indicates that such gutters are the dominanA. aegypti habitat in Paramaribo, Surinam, where actieradication efforts have been carried out. In Albina, a towwhere these efforts had been discontinued, relatively largnumbers o f ground-level infestations have been found.

IntroductionAedes aegypti is one of the most widespreadmosquito species on earth. Being present orhaving been present in all tropical and sub-tropical countries, it has developed diverse

habitats in different parts of its range. InAfrica, where it probably originated, the larvaecommonly inhabit tree holes in swampy areas(Surtees, 1960); but in most of the world theyare found primarily in man-made containersand only secondarily in natural containers. Thecontainers most frequently used vary fromplace to place, depending on the types avail-able. Major categories of artificial containersused by A. aegVpti have ranged from tires andmetal containers in Tanzania (Rao, et al., 1969)to ant traps and large earthenware jars inMalaya (MacDonald, 1965) to old tires in theUnited States (Tinker, 1964). Because of thisadaptability, the mosquitos habitat must bestudied in the particular areas where it is to becontrolled or eradicated in order to determinewhat containers play an important role in itspropagation.Surinam, where large numbers of A. aegyptilarvae have been reported in roof gutters andcatch basins, provides a case in point. Thesehabitats have not been encountered often inother countries, and they have therefore been

1Also appearing n Spanish n the Boletin de laOficina Sanitaria Panamericana.2Basedon researchperformed with the assistanceand cooperation of the Ministry of Health, Govem-ment of Surinam.3Previously a member of the Jamaica nsecticideTesting Unit of the Pan American Health Organtia-tion, the author recently transferred o the Unit forResearch n the Epidemiology of Malaria n ProblemAreas n El Salvador.

called atypical sites. However, they are moproperly termed uncommon, rather thatypical, because they do possess he typicalfeatures required by A. aegypti. Thus extensiroof gutter infestations have also been found other countries, such as Guyana, where larnumbers of roof gutters exist (DeCaires, 194The present study investigates the pattern

distribution of A. aegypti larvae in a number typical areas of Surinam. The data presenthere will show the importance of the variotypes of habitats involved.Surinam has an active A. aegypti eradicatiocampaign which employs the standard perifoctechnique (PAHO, 1957). Every possible larvhabitat on all premises is treated with fenthioand Abate on a two-month treatment cycle.addition, due to heavy infestations speccrews inspect and treat roof gutters. Becauthis latter work is time-consuming it involvestreatment cycle of about a year.Because of the heavy infestations of aegVpti in roof gutters after applications insecticide, it has often been felt that ttreatment of ground-level habitats was forcinA. aegypti into the roof gutters. An alternahypothesis is that large numbers of A. aegyhave survived the applications because the gters are very difficult to treat. These hypothescan be tested by comparing mosquito habitain treated and untreated areas-to determiwhether the species prefers the roof gutthabitat or whether it is being driven there.Procedures

The work reported here was based oncomprehensive survey made in February 13293


2/9

294 PAHO BULLETIN * Vol. VIII, No. 4, I974

of all possible larval habitats in five areas ofSurinam.Selection Criteria

In choosing these five areas, the followingfactors were considered: (1) climate, (2) size ofthe human community, (3) socioeconomic con-ditions, (4) past treatment history, and (5) pa,rA. aegypti infestation record.CZirruzte. There is little climatic variation inSurinam. Because of this, climate was not usedas a criterion in choosing survey areas. It shouldbe noted, however, that the two localitiessurveyed had similar rainfall patterns (89.4inches per year in Paramaribo and 97.5 inchesin Albina) and that the surveys were doneduring the rainy season. During the 18 days ofthe investigation it rained some on all but threedays.Community size. A. aegypti infestations aregenerally larger and more complex in largerhuman communities. Thus a study that aspiresto be complete should survey several commu-nities of different size. Our particular investiga-tion used the following size categories inselecting the communities to be surveyed:

1) Rural communities-no organized settle-ment ;2) Villages-less than 2,000 people, less than500 houses;3) Towns-2,000-10,000 people, 500-2,500houses;4) Cities-over 10,000 people, over 2,500houses.

For lack of time and because lower infesta-tion rates have generally been found in ruralareas and villages of Surinam, it was decidedthat the survey would cover four areas in thecity of Paramaribo and one in the town ofAlbina.

five socioeconomic land-use categories listebelow were considered in choosing the areasbe surveyed:1) Lower-level residential: Small homeoften crowded and in poor condition, whosresidents are usually members of the laborin

class.2) Middle-level residential: Medium-sizehomes, generally in good condition, whosresidents are usually members of the middclass.3) Upper-level residential: Large homes, in good condition.

4) Business areas: Shops and light industr5) Industrial areas: Large factories awarehouses, often with sizeable lots used fstorage.

While one of these categories usually prdominates, there are often mixtures, especiain the lower residential and business areas. towns and villages no one category is larenough to be sampled separately except for tlower residential area.Treatment histoly. Treatment would logicly be expected to change the pattern infestation. Such change depends on tamount and type of treatment. Therefore, tfollowing patterns of past treatment were cosidered in choosing the areas to be studied: No treatment; (2) Recent treatment (for lthan a year); (3) Lapsed treatment (for mothan one treatment cycle); and (4) Long-tetreatment (for more than a year). The patteof infestation in categories (1) and (3) shoube similar, especially after a long lapse. Surinam all towns have been treated for mothan a year, but the treatment in some plahas lapsed. Albina was picked as an examplethe latter to provide a basis for compariswith Paramaribo, which has received long-tetreatment.


3/9

Tinker . A. AEGYPTJ LARVAL HABITATS IN SURINAM 2

has been relatively unsuccessful. The four cat-egories of infestation used in choosing studyareas were adopted from the Manual of Upera-ticms for an Aedes aegypti Eradication Service(PAHO, 1957). These are: (1) high (over 15 percent of the houses infested); (2) moderate (2-15per cent of the houses infested); (3) slight(infestation, but less than 2 per cent of thehouses infested); (4) uninfested.Because of the short time available, it wasfelt that study areas should be picked whererecent surveys had shown moderate or highlevels of infestation, so that a statisticallysignificant number of infestations would befound. This eliminated most towns and upper-level residential areas, because they were eitheruninfested or had only slight infestations.Based on these considerations, four areaswere picked in Paramaribo and one in Albina.Those in Paramaribo are areas where persistentinfestations have been undergoing long-termtreatment. They can be categorized as follows:

Area l-Lower-level residential, near citycenter;Area 2-Lower-level residential, at edge ofcity ;Area 3-Middle-level residential;Area 4-Old lower-level residential area bor-dering business districts.Portions of areas 2 and 4 contain middle-class residences. The Albina area, where treat-ment had lapsed, was typical of town areas inthat it contained a mixture of businesses,

lower-class residences, and middle-class reidences.Sampling Technique

All premises were thoroughly inspected boinside and out. A census was made of potential A. aegypti habitats, including rogutters: all were classified, counted, examineand all infestations were noted. A sample larvae was collected from each infestation sand identified microscopically. In all cases hpreliminary identification of larvae as Aaegypti was confirmed.A standard list was used to classify potentiahabitats. This list included the followingentries: cisterns or tanks, drums and barrelclay containers, water plants, small containerroof gutters, tires, other containers, street catcbasins, and tree holes.Results and DiscussionInfestation Levels

In each area the level of infestation wdetermined (see Table 1). In Paramaribo, areahad a moderate level of infestation while are2, 3, and 4 had high levels. The Albina area wvery heavily infested.Containers

A particular type of container can play TABLE l-Houses infested with A. aegypti lmae, showing proportion with gutter and ground infestations.

survey HOUSESarea inspected

Houses infested with A. aepvpn* % infested houses with guttervs. gmund infestation sites*

Total In gutter on gmund Gutter and groundIn On GutterNo. % NO. % NO. % NO. % gutter ground and grou

Area 1Area 2Area 3Am4Paramtibo

(subtotal)Albina

Total

95 8 8.4 4 4.2 4 4.2 0 0.0 50.0 50.0 0.0104 21 20.2 18 17.3 4 3.9 1 1.0 85.7 19.0 4.8118 20 17.0 10 8.5 14 11.9 4 3.4 50.0 70.0 20.0

84 22 26.2 15 17.9 11 13.1 4 4.8 68.2 50.0 18.2

401 71 17.7 47 11.7 33 8.2 9 2.2 66.2 46.5 12.7114 45 39.5 15 13.2 32 28.1 2 1.8 33.3 71.1 4.4515 116 22.5 62 12.0 65 12.6 11 2.1 53.4 56.0 9.5

*Houses with both gutter and ground infestations arc listed in all columns.


4/9

TABLE 2-Numbers of containers found, listed by type.

survey areaAWL1Area2Area 3Area 4

Small containers Miscellaneous containers Roof gutters Water BUT.& Catch Clay Cisterns TreeNo. % of total No. % of total No. % of total phts and drums Tires basins containers or tanks holes Total

E 197 7.3 112 4.2 2 13 z; 6 2 0 i 2,68875:o 169 6.4 171 6.5 9 2 2,637386 ::; z 7.0 108 E77.7 164 10.4 46 10 z Yci :; : l?i 3,9912,366Pa~m~arlbo (subtotal) 2::;: 78.40.1 91626 7.0.8 81001 6.9.1 2182 1E 1 950 13-l 346 4 17 11.682,274

Total 11,886 79.5 1,042 7.0 1,011 6.8 270 253 245 136 50 46 17 14,956

TABLE 3-Numbers of containers found with water.

survey ama

Small containers Mlhcellaneous containers Roof guttersNo. with % with No. with % with No. with % with Water Barrels Catch clay Cisterns Treewater water water water water water plants and drums Tires basins containen or tanks holes Total

Area 1Area 2Area 3Area 4430 18.0 z 27.4 9 8.0 18:tIt 37.37.5 1:; 2; .z 2: 7 ii i 0 Y %12:9 ii 90 :4.3 68 27:5 41 : 18 ii 0 A ,@I;

Pa~myribo (subtotal) 1,45385 15.78.5 ci 46.72.9 30402 50.71.5 1736 2 452 120 4 3: i 2.568l8Total 1,943 16.3 482 46.3 406 40.2 219 117 77 122 11 37 2 3,416

TABLE ANumbers of containers infested with A. aegypti.

survey atea

Smallontainers Roof gutters Water plants%hlfuted %hlf&d R inksted MlSCd-of of of lanmus Barrels cisterns

inE;ed of mntiers No. of containers No. of containers con- andCatch clay TtWtotal with water tnfest d total with water infes ted total with water tallers drums Tires basins containen t& holes Total

Area1 : 0.04 11.1 4.5 55.6 i 11.5 33.3 0rea2 0.1 10.3 14.0 82.8 0.0 0.0 x x 0 8 8 0 2;Area3 12rea4 6 3 % . 18 :% 5:: : 1::; 26 i : : 0 : A :1 0 iiParamaribo (subtotal) E 0.2 5:: E 7.4 9.0Albina 1.1 10.9 it: 14 id 16.3 : 1: ; A 0 1001 ; A 86

52 0.4 28.0 02 8.1 44.1 23 8.5 12.4 5 13 5 1 1 3 1 186


5/9

Tinker . A. AEGYPTI LARVAL HABITATS IN SURINAM 29

important role in A. aegypti propagation if ahigh percentage of the infested containers areof that type. This can come about if manycontainers are of the type in question, or if alarge proportion of that particular type areinfested. In our survey the first case wasillustrated by small containers, the second bydrums in Albina and by roof gutters in bothAlbina and Paramaribo.The distribution of the different types ofcontainers was typical (see Table 2). Most ofthe containers (79 per cent) were classified assmall containers (these were mostly tin cans).Still, the number of such containers was notgreat when compared with other countries, theoverall average per premises being 23 smallcontainers. In Jamaica the average per pre-mises is 120. While we found them to producemany infestations, they were not a goodhabitat. Only a small proportion (16.3 per cent)contained water (Table 3), and only 0.4 percent were actually infested; but because therewere so many they accounted for a significantproportion (28 per cent) of all infestations, asshown in Table 4.

Water-plant containers and tires. Fewerwater-plant containers and tires were foundthan might have been expected, these typesrespectively accounting for only 1.8 and 1.6 percent of all containers. On the other hand, bothtypes provided good habitats and both har-bored a significant proportion of the infesta-tions. Overall, 8.5 per cent of the water plantswere infested and these accounted for 12.4 percent of the total number of infestations. Therespective figures for tires were 2.0 and 2.7 percent (see Table 4).

The water plants role appears ess importantwhen it is considered that 12 of the 14 infestedwater plants in Albina were found on thepremises of one house. Without these premisesthe water plants share of the total infestationobserved in Paramaribo and Albina would dropfrom 12.4 to 5.9 per cent. Though this is stillan important figure, growing plants in water hasnot been as widespread in Surinam as in the

untreated parts of Jamaica water plants habeen found to account for 30 per cent of thinfestations.

Drums and Tanks. Water stored in drumand tanks provided an important habitat Albina but not in Paramaribo. This was trueven though the proportion of Albina surveyedoes have a piped water supply. In Paramaribthe number of drums was low, making up on0.8 per cent of all the containers; in contrasthey were relatively common in Albina, whethey represented 5 .Oper cent.The same observations were true of tankThey made up 0.3 per cent of the containers Paramaribo and 1.3 per cent in Albina, and thdifference showed up even more sharply in tinfestations found. Only one drum or taninfestation was observed in Paramaribo, thbeing in an ornamental tank. On the othhand, two infested tanks and 13 infested drumwere found in Albina, these constituting 2.3 pcent and 15.1 per cent of the infestations therThe differences presumably stem from Paramribos ban on water storage and its active aegypti eradication campaign.

Catch basins. Also known locally as ragullies, these are considered an atypichabitat for A. aegypti, but they do meet thgeneral requirements of a container with hasides and a fluctuating water level.A catch basin is the structure which receivrainwater from the street and passes t into thstorm sewer. Within it is a small settling baswhich contains water all the time, and whichas the purpose of removing debris from twater so as to prevent the sewer from cloggiup. This is an ideal habitat for C&X fatiganand occasionally A. aegypti.In many U.S. cities catch basins are the masource of CL&X fatigans and are treated regulaly. Occasionally A. aegypti have also befound in them, particularly when the genelevel of A. aegypti infestation was high. Thpattern appears to be the one prevailing Surinam. Of the 136 catch basins inspect


6/9

298 PAHO BULLETIN . Vol. VIII, No. 4, 19 74

uegypti. On the other hand, 26 of them (19 percent) were infested with C. futigans. In the twoareas with a significant number of catch basins(areas 3 and 4) they were a C. fatigans habitatof considerable importance. The two areas hadthe largest numbers of C. futiguns infestations,and the catch basins alone accounted for 76.9and 66.7 per cent of these (see Table 5).Roof gutters. The results of our study showthat roof gutters are the dominant habitat of A.uegypti in Surinam. In Paramaribo, this onecategory of container was responsible for 60.0per cent of the infestations observed and for66.2 per cent of the infested premises (seeTables 1 and 4). It was thus more importantthan all the other categories of containerscombined.This major role resulted partly from thelarge number of roof gutters in use and partlyfrom the high proportion of gutters infested.They were the third most common type ofcontainers, after small containers and othercontainers; and they had the highest infestationrate (7.4 per cent) of any category, the nexthighest categories being water plants (4.1 percent) and tires (1.5 per cent).

The same was true in Albina, where roofgutters were the site of infestation on 33 percent of the infested premises, were the secondmost common category of container (6.1 percent of the total), and had the second highestrate of infestation (10.9 per cent). The Albinasurvey showed water-plant containers to havethe highest rate of infestation (26.9 per cent),but this was due to the high rate at a singlepremises where 12 of 20 water plants were

infested. In the rest of the 113 premisessurveyed, only two of 32 (6.5 per cent) wereinfested. Other containers with high infestationrates in Albina were drums (7.9 per cent), tanks(4.8 per cent), and tires (4.0 per cent).One of the most important factors behindthis pattern was the high proportion of build-ings with roof gutters in both Paramaribo andAlbina (see Table 6). On the average 66.1 percent of the buildings had them in Paramariboand 62.3 per cent in Albina. Many of thesegutters contained water (56.2 per cent inParamaribo, 67.6 per cent in Albina), andnearly a third of those containing water wereinfested (31.5 per cent in Paramaribo and 31.3per cent in Albina). In areas 1 and 2 thepercentage of wet gutters infested was especial-ly high (57.1 per cent in area 1 and 50.0 percent in area 2).Two sets of data indicate that roof gutterinfestations are often the source of infestationsin containers on the ground. These are (1) thedistribution of infestations with pupae (pupalfoci) and (2) the spatial relationship of gutterand ground infestations.When infested water contains pupae, this isgenerally recognized as a sign that the focus ofinfestation is well established and is providing asource for infestation of surrounding areas. Thisis generally true, though in the case of con-tainers with highly intermittent water it ispossible for one brood to emerge before theeggs for the next brood are hatched. Thus someestablished sources of infestation will notcontain pupae if they are inspected too soonafter the eggshatch.

TABLE S-Catch basins and Culexjiatigans infestations.

survey areaArea1Area 2Am3Area 4Paramaribo (subtotal)Alblna

Total

AU containers Catch basinsPercentage of c. jatigans

No. No. with No. with No. No. with No. with infestations foundinspected A. aegypti c. fieigam inspated A. aegypti c. fatigm In catch basins

2,688 9 2 6 0 0 0.02,637 29 2 9 0 0 0.03.991 30 26 99 0 20 76.92,366 32 9 20 1 6 66.7

11,682 100 39 134 1 26 66.73,274 a6 6 2 0 0 0.0

14,956 186 45 136 1 26 57.8


7/9

Tinker , A. AEGYPTI LARVAL HABITATS IN SURINAM 29

t

4

1

TABLE 64. aegypti mof gutter infestations.

survey areaTotalNo.

Houses inspected Houses withrwf gutten

With roof With water With A. aegvpti- Houses with watergutters in gutters infested paterr % with in mof gutters.

water in % with % infested withNO. % NC.. 56 NO. % gutters A. aegypti A. aegypti

Area 1 9s 42 44.2 7 7.2 4 4.2 16.7 9.5 57.1Area 2 104 63 60.6 36 34.6 18 17.3 57.1 28.6 SO.0Ares 3 118 90 76.3 67 56.8 10 a.5 74.4 11.1 14.9Area4 &I 70 83.3 39 46.4 15 17.9 55.7 21.7 38.5Paramaribo kubtotal) 401 265 66.1 149 37.2 47 11.7 56.2 17.7 31.5Albina 114 71 62.3 48 42.1 1s 13.2 67.6 21.1 31.3

In both Paramaribo and AIbina, a higherproportion of the infestations with pupae werefound in the gutters than on the ground (seeTable 7). In Paramaribo 52.2 per cent of thegutter infestations were classed as pupal foci, asopposed to only 25.0 per cent of those on theground; and in Albina, 72.7 per cent of thegutter infestations were pupal foci, while only12.1 per cent of the ground infestations were ofthis type. Stated another way, 52.1 per cent ofthe premises with roof gutter infestations inParamaribo had pupal foci, but this was true ofonly 30 per cent of those with ground infesta-tions. Likewise, in Albina pupal foci werefound on 60.0 per cent of the premises withroof gutter infestations but on only 15.6 percent of those with infestations at ground level.These findings indicate that roof gutters are afrequent source of further infestation in bothParamaribo and Albina.To further examine the relation betweenground and gutter infestations, all locations

were marked on a map and were classified terms of their proximity to each other (sTable 8). Most of these classifications weconfnmed in the field. Based on these dateach house surveyed was placed in one of thfollowing categories:1) With independent gutter infestation;2) With independent ground infestation;3) With one or more gutter infestationlocated less than 50 m from a ground infesttion;4) With one or more ground infestationlocated less than 50 m from a gutter infest

tion;5) With both gutter and ground infestationsIn Paramaribo 39.5 per cent of the infeste

premises surveyed had infestations of the interelated types (categories 3, 4, and 5) as showin Table 8. Of the remaining independeinfestations, 40.9 per cent were in roof gutteand 19.7 per cent were on the ground. ThTABLE 74. aegypti pupae in gutter and gmnnd-level infestations.

No. of ihated contim No. of premises with infested % infested % blfeshdcootaiaers plI&S

GUtt.55 Other GUttfXS other mntablers with pupae withpupaLanrac Larvae w= Larvae other ItI otLarvae and Larvae and Iamae and Larvae and con- In con-

Survey area ody pupae Total Only pupae Total OdY pupae Total only popae Total Gutters tniners @ters trainerArea1 2 3 5 3 1 4 1 3 4 3 1 4 60.0 25.0 75.0 5.0Area2 13 11 24 4 1 5 10 8 18 3 1 4 45.8 20.0 44.4 25.0Area 3 6 7 13 12 5 17 S 5 10 9 5 14 53.8 29.4 50.0 35.7Area 4 8 11 19 11 3 14 7 9 16 8 3 11 57.9 21.4 56.2 27.3Paramnribo 29 32 61 30 10 40 23 25 48 23 10 33 52.5 25.0 52.1 30.3Albim 6 16 22 51 7 58 6 9 15 27 5 32 72.7 12.1 60.0 15.6

Total 35 48 83 81 17 98 29 34 63 50 15 65 57.8 17.3 54.0 23.1


8/9

300 PAHO BULLETIN . Vol. VIII, No. 4, 1974

TABLE 8-RelationshIps of gutter and ground A. aegypti hfestatio~.Number of houses infested Percentage of houses infested

Site of infestation Site of infestationNumber Gutter Ground Gutter Ground

of Glitter @fear Gutter (Near Gmund GUttM (Near Glitter (Near Groundhouses Total &de.- ground in- and gunern- (Inde- Unde- ground in- and gutter in- (Inde-

Sutvey area inspected I nfested pendent) festntion) ground festation) pendent) pendent) festation) ground festation) pendent)Ares 1Area 2Area 3Area4Paramaribo

(subtotsl)Albina

95 8 4 0 0 0 4 53.0 0.0 0.0 0.0 50.0104 21 1 4 3 1 2 1 66.7 14.3 4.8 9.5 4.8118 20 4 2 4 6 4 20.0 10.0 20.0 30.0 20.0

84 22 7 4 4 2 5 31.8 18.2 18.2 9.1 22.7

401 71 29 9 9 0 14 40.9 12.7 12.7 14.1 19.7114 45 6 7 2 9 21 13.3 15.6 4.4 20.0 46.7

pattern was most striking in area 2, where 66.7per cent were independent roof gutter infesta-tions; and it was also evident in area 4, where31.3 per cent of all infestations were of thistype. These findings tend to indicate that inareas 2 and 4 the infestations were spreadingfrom the roof gutters to the ground.However, different patterns were found inareas 1 and 3. In area 1 the two types ofinfestation were completely independent andthere was no evidence of any movement fromone type to the other. In area 3 all categorieswere about the same size, a finding that couldindicate movement in both directions.A different pattern was also found in Albina.Here 46.7 per cent of the infested premises hadindependent ground infestations, while only13.3 per cent had independent gutter infesta-tions. This indicates that the infestation mighthave been spreading from the ground to theroof gutters.A comparison of the infestations in Albinaand Paramaribo is very useful in showing the

importance of roof gutters. After almost ayears lapse in treatment, and with a very highrate of infestation, the situation in Albina canbe considered typical of an untreated A.aegypti population. When the data are ex-amined, a striking similarity is found betweensome of the Albina figures and the averagefigures for Paramaribo. As shown in Tables 1,4,and 6, the percentage of houses with roofgutters (66.1 vs. 62.3) is similar, as is thepercentage with wet roof gutters that areinfested (3 1.5 vs. 3 1.3), the percentage of roofgutters with water that are infested (7.4 vs. IO),and the percentage of houses with roof gutterinfestation (11.7 vs. 13.2). Because of this greatsimilarity, it must be concluded that the roofgutter infestation in Paramaribo is typical forSurinam, and that the main difference in thetwo localities is that the level of groundinfestation has been reduced in Paramaribo.There is no evidence of A. aegypti being drivento the roof gutters by treatment in Paramaribo.

SUMMARYIn 1972 a study was made of Aedes aegypti In Albina stored water was a major source ofhabitats in Surinam. This was based on a infestations. but not in Paramaribo. This wascomprehensive survey of all potential habitats probably due to Paramaribos ban on waterin four areas of the capital, Paramaribo, and in storage and its A. aegypti eradication program.part of the town of Albina. It was found that roof gutters constituted aA. aegypti larvae were found in storm sewer major habitat of A. aegypti in all areas sur-catch basins, but not in large numbers, although veyed. In fact, the proportion of houses withCulex fcftigans infestations were very common infested roof gutters in the treated areas of


9/9

Tinker . A. AEGYPTI LARVAL HABITATS IN SURINAM 30

Y

lapsed, were very similar. The main differences foci of A. aegypti. There is no evidence that in infestation patterns were those due to higher aegypti are being driven to the roof gutters levels of ground infestation in Albina. insecticide treatments. Rather, the number Evidence provided by the presence of pupae ground infestations appears to have beat some sites and by the spatial relationship of reduced in treated areas, leaving the guttgutter and ground infestations indicates that infestations relatively unaffected.roof gutters are harboring numerous reservoir

REFERENCES(I) De Canes, P. F. Aedes aegypti control iu absenceof piped potable water supply.Am J 7?op Med21: 733-743, 1947.(2) MacDonald, W . W. Aedes aegypti in Malaya: II.Larval and adult biology. ARR Trap MedParasitol 50: 339~414,1959.(3) Pan American Health Organization. Manual ofOperations for an Aedes aegypti Eradication

Service, Part Two: Manuals of Instruction(Mimeographed). Washington, D.C., 1957.(4) Rao, T. R., M. Trpis, J. D. Gillett, and C.Teesdale. Breeding Habitats and Seasonal IRci-

dences of Aedes aegypti in Dar-Es-SalaaTanzania, as Assessed by the Single-larvae Svey Method. World Health Organization, Docment WHO/VRC/69.153, Geneva, 1969.(5) Surtees, G. The breeding behavior of the typform of Aedes (Stegomyia) aegypti (L.) south-eastern Nigeria in relation to insecticidcontrol. BullEnt Res 50: 681-686,196O.(6) Tinker, Milton E. Larval habitat of Aedes aegy(L.) ln the United States. Mosquito News 2426-432,1964.

4h

aedesaegypti larval habitats in surinam

Documents