Panaji (Goa)

BackgroundGoa field unit was established in June 1989 followinga severe outbreak of malaria in 1986 at a large con-struction site in Panaji, the capital city of Goa. It isnoteworthy that less than seven cases of malaria werereported from Panaji in 1984 and 1985. In May 1986,167 malaria cases were reported from labour hutmentin the vicinity of a swimming pool under constructionin Campal area. Gradually malaria spread to adjoin-ing Miramar area and the total cases reported were352 including one case of P. falciparum with an API of7.2 in 1986. In 1987, due to accelerated transmission,many parts of the city were severely affected and4,406 malaria cases including seven P. falciparumcases were recorded with API of 87.8. In 1988, Pf inci-dence further rose sharply to 242 cases accounting for

4.26% of the total 5,677 cases detected with a furtherascent of API to 110.4. A sharp increase in slide pos-itivity rate (SPR) from 5.38% in 1986 to about 20% inboth 1987 and 1988 was also noticed. In 1989, al-though the total malaria cases declined to 3,523 (API64.9), yet the Pf incidence increased to 520 cases.Consequently, SFR and Pf % also increased to 2.47and 15.2% respectively. On the request of the Govt.of Goa, a field unit was thus established at Panaji toinvestigate the role of migration malaria and to devel-op a suitable strategy for malaria control. Since 1989,the unit has undertaken studies on bioecology ofmalaria vector, evaluation of bioenvironmental me-thods of control, health impact assessment of KonkanRailways, transfer of vector control technology to Mor-mugao Port, malaria teaching programme in schools,monitoring of drug resistance in P. falciparum, etc.

First site for the demonstration of bioenvironmental malaria control in urban areas. The fieldunit has made many outstanding contributions such as:

� For the first time a joint programme of work was developed with the Konkan Railways toconcurrently study the proposed works at the design and construction stage and incor-porate remedial measures. As a result 800 km rail track area is free from mosquitobreeding

� Large-scale application of Bacillus thuringiensis and Bacillus sphaericus in the control ofAnopheles stephensi at construction sites. This led to successful malaria control inPanaji

� Revision of municipal by-laws to prevent mosquito breeding

� For the first time malaria teaching is being offered as an optional subject for 10+2school children. Every year 50,000 students study about malaria in Goa

� Mosquito control in Goa Port was demonstrated and the technology was transferred tothe industry

� Work has begun on malaria burden estimation as per the World Bank procedure. Thiswork has been taken up in Jharkhand state

17PANAJI

Activities, Progress and Achievements

Bioenvironmental control of malaria inPanaji

The field unit started its operations in Panaji and inorder to delimit the problem of malaria, launched twopronged approaches by starting vector and parasitesurveillance in coordination with National MalariaEradication Programme (now NVBDCP). Systematicweekly vector surveillance was conducted in 1989 and1990. The city was divided into 15 sectors and 67,360habitats were checked for vector breeding. Of these,3,010 (4.5%) were found positive for immatures ofdifferent species of mosquitoes and 747 (1.1%) for An.stephensi (Kumar and Thavaselvam, 1992). Although44.4% of the tyres checked were positive for differentmosquito species, only 3.9% were found to containmalaria vector breeding. On the other hand, among8.1% fountains with larvae, 4.8% had An. stephensi(Fig. 1). The remaining habitats showed positivity for thevector ranging from 0.4 to 2.4%. In terms of proportionof habitats supporting vector breeding, overhead tanks(34%), curing waters (16%) (Figs. 2 a and b), masonrytanks (16%) and wells (11%) were the major contribu-tors (Fig. 3). Some of the activities under bioenviron-mental control methods are shown in (Fig. 4).

Seasonal population trends of vector

To study the seasonal build-up of An. stephensi popu-

lations in different habitats, monthly data of immaturestages were pooled up and analysed. It was observedthat the vector positivity declined from 1% in Januaryto 0.4% in March 1990 after which it showed upwardtrend as it reached its peak in June 1990. Thereafter,the vector immature populations declined to 0.5% inAugust and maintained a steady trend until December.It may be noted that the rising population trend fromMarch to June (Fig. 5) coincided with the increase inthe minimum temperature from 20.7°C in February to25.6°C in May 1990. On the other hand, the maximumtemperature, which did not show much variationbeing 32.4°C in February and 32.5°C in June, did notseem to influence the vector population build-up(Kumar et al., 1991, 1997). Increase in the relativehumidity from 80% in February to 91.5% in Juneseemed to favour longevity of the vector adults andthereby in prolonging transmission. This suggestedthat January to March months were crucial for vectorcontrol when the vector populations were at a low ebband confined to relatively few breeding habitats. Thevector build-up in the subsequent months of April toJune, however, enhanced malaria transmission.

Another crucial factor in malaria transmission was therainfall. It is noteworthy that Goa received an annualrainfall of 2500 mm during southwest monsoons fromMay to September (Data source: MET Office, Goa).During May and early June, rainy and intermittent dryhot spells coupled with high humidity were highlyfavourable for vector build-up. As the rains stabilisedin July, there was decrease in maximum and minimum

Fig. 1: Proportion of habitat positivity for mosquitoes and An. stephensi in Goa (1990)

18 IDVC PROJECT PROFILE

Figs. 2 a & b: Breeding habitats of An. stephensi (a) Overhead tanks; (b) Curing waters

(a) Defective lid

Fig. 3: Contribution of various habitats to the total positive habitats withAn. stephensi in Panaji, Goa (1990)

Fig. 4: (a) EPS beads introduced in a disused well; (b) Drain being treated with B. sphaericus;and (c) Larvivorous fish being introduced in a village well

a b c

(b) Curing water

temperature (from 32.5°C in June to 28.6°C in August,1990 compared with 36°C in May 1990). The relativehumidity, however, touched its peak at 95%. FromAugust onwards, malaria cases showed steady de-cline as the monsoon receded.

Malaria incidence in construction workers

The analysis of data showed that malaria incidence

among construction workers was much higher than inthe local residents in Panaji in 1990. In migrant work-ers (population: 2,829), the slide positive rate (25.7%),slide falciparum rate (5.6%), Pf percentage (21.8%)and parasite index (528.1) were significantly higherthan the local residents (population: 54,122) being19.8%, 3.6%, 13.4% and 37.97 respectively (p<0.05).Floor area under construction in the conservationzone (Wards 1–7) was 22,693 m2 and there were 491

19PANAJI

Fig. 5: Seasonal build-up: Percent habitats positive for larval/pupal stages of all mosquito speciesand An. stephensi in Panaji, Goa (1990)

migrant workers in this zone. On the other hand, inthe accelerated construction zone (Wards 8 to13),1,14,025 m2 floor area was under construction with2,338 migrant construction workers residing in thisarea (Kumar et al., 1991). It was observed that malariaincidence was significantly less in both local residents(API–17.7) and migrant workers (API–340.1) in theconservative zone as compared to the acceleratedconstruction zone being 51 and 567.6 respectively.This situational analysis proved vital in prioritising bothvector control and anti-parasitic measures. The para-site surveillance was made weekly and special squadswere pressed into service to mop-up malaria casesamongst migrant construction workers.

Vector control

As part of bioenvironmental strategy, three methodswere applied for vector control.

Source reduction

About 1000 tyres were dried and stored indoors, 1676small, medium and large domestic containers wereinverted or disposed off. Besides, 2300 barrels andtins were either inverted or disposed off, 4321 curingwaters supporting increased vector breeding weredried up with sand, 167 ornamental tanks were alsoperiodically dried up. Water was completely evacuatedfrom 1250 underground masonry tanks, with pressurepump in the post-monsoon season. In 1789 masonry

tanks a hole was drilled on the side wall near its bot-tom to drain out water completely to render them dry.Over 1500 overhead tanks were either inverted (iffound disconnected) or covered after removing larvaefrom them.

Larvivorous fish

Larvivorous fishes were the main vector control tool.Over 2,70,000 fishes belonging to six species wereintroduced in the breeding habitats. Of these, 93.5%were indigenous fish Aplocheilus blocki and only 4.47and 1.48% respectively belonged to P. reticulata andG. affinis. In 2,688 masonry tanks 1,30,000 fisheswere introduced repeatedly at an interval of threemonths. Fishes were introduced in 2,786 wells, 317ornamental fountains, 437 abandoned overheadtanks, 184 rain pools and ditches and 98 drains.

Biolarvicides

For the first time in the Goa state, B. sphaericus H5a5b (B101) and B. thuringiensis israelensis H-14 strain164 were applied @1g/m2 in the positive habitatscontaining immature stages of anophelines. Themaximum use of biolarvicides was done in the curingwaters retained to cure newly cast cement slabs. Al-though curing waters were shallow, yet they sup-ported heavy vector breeding. B. thuringiensis israe-lensis and B. sphaericus were sprayed in the ano-pheline breeding habitats as follows: curing water

20 IDVC PROJECT PROFILE

(area sprayed 677 m2 & 1645 m2 respectively), groundwater tanks (156 m2 & 530 m2), masonry tanks (435 m2

& 198 m2), rain water pools on terraces and slabs inthe construction sites (433 m2 & 145 m2), and stormwater drains (69 m2 & 51 m2) during initial phase ofmonsoons when in small water pockets anophelinebreeding was encountered.

Parasite control

In addition to the existing passive case detection andtreatment facility at the Urban Health Centre and theGoa Medical College Hospital, a malaria clinic wasoperated at Goa field unit. The services of the clinicwere availed of by the general public, Goa MedicalCollege, general practitioners, health services forcross-examination of blood smears retrieved fromdifferent PHCs and UHCs of Goa and for training. Onthe advice of IDVC field unit, the NVBDCP (thenNMEP) pressed into service special mobile squads forweekly active case detection in construction workers.The treatment to malaria patients was dispensed asper the NVBDCP drug policy within 24 h of malariacase detection.

IEC and community participation

IEC campaign included house-to-house visits, healthexhibitions at construction sites near labour hutmentsand residential colonies in all wards of the city. At thebeginning of the implementation of bioenvironmentalcontrol programme, there was a low awareness and

knowledge about malaria in the community so muchso that garbage and gutters were considered respon-sible for malaria. The private practitioners had littleexperience of treating malaria cases as they had notseen malaria earlier during their practice (Salelkar,1993). So when the bioenvironmental malaria controlproject was launched in Panaji, a number of interac-tive programmes were initiated with private practitio-ners through Indian Medical Association of Goa. Agreat deal of emphasis was laid on health educationto harness community participation in the programme.Health education was imparted through house visits,lectures and exhibitions in the educational institutions,residential colonies and labour camps (Kumar et al.,1994). Videos were shown on malaria and trainingwas imparted on the prevention of malaria to the en-gineers and the supervisors working at the construc-tion sites.

Impact assessment

A focused vector and parasite control approach in1991 and 92 made desired impact on malaria trans-mission. Selective vector control interventions duringJanuary to May prevented build-up of the populationsof An. stephensi. As a result, the peak in vector popu-lations visible in 1990 during monsoon months waseliminated in 1991 and 92. This produced desiredimpact on malaria transmission as slide positive ratesfor malaria showed a steep decline from 22.5% in April1991 to below 10% in the remaining months of 1991and 1992. Similar trend was also seen in case of slide

Fig. 6: Malaria incidence in Panaji from 1985–99 showing impact of bioenvironmentalcontrol of malaria from 1989–92

YEAR

21PANAJI

falciparum rates, which declined from 8% to less than4% during this period. The child parasite rate and childfalciparum rate also declined from 18.6 and 5.2% in1990 to 11.1 and 1.5% in 1991 and to 1.6 and 0.5%in 1992 respectively. Similarly, infant parasite rate andinfant falciparum rate also declined from 14 and 2%respectively in 1990 to 10.8 and 1.5% in 1991 and tonil in 1992. Thus, the introduction of bioenvironmen-tal interventions led to control of malaria transmissionin Panaji. The incidence of malaria in Panaji declinedby 88.5%—from 3,938 cases in 1990 (API–88.08;SPR–19.7%) to 1,556 cases in 1991 (API–36.21;SPR–15.1%) and to a further low of 450 cases in 1992(API–10.3; SPR–6.3%) (Fig. 6).

Malaria education in schools

With an aim to make students malaria literate inschools of Goa and to mount a self-action against thedisease, a systematic curriculum-based educationprogramme was launched in Goa (Lopes et al., 1993).The partners in this innovative programme besidesGoa field unit were Indian Red Cross Society, Depart-ment of Education, Govt. of Goa and Goa Board ofSecondary and Higher Secondary Education. During1992–99, 29 workshops were organised for training971 teachers (Fig. 7). To facilitate training of the teach-ers, a book entitled ‘Elementary Malariology’ waspublished by the Goa Board of Secondary and HigherSecondary Education (Kumar, 1996). The programmein schools was launched from standard 8th to 12th in228 schools targeting 53,462 students throughoutGoa (Table 1). The malaria education was impartedthrough trained teachers as per the Govt. approvedsyllabus and 147 malaria exhibitions were organised

Fig. 7: Teachers observing malaria parasites undermicroscope

Table 1: Progressive coverage of schools under malaria education programme

JRC (Std. VIII-X) YRC (Std. XI & XII) Total

Schools Students trained Schools Students trained Schools Students trained

1992–93 81 16,211 Nil Nil 81 16,211

1993–94 98 19,353 Nil Nil 98 19,353

1994–95 108 21,018 5 1,115 113 22,133

1995–96 116 28,712 25 7,219 141 35,931

1996–97 141 39,395 35 11,532 176 50,937

1997–98 189 41,235 38 12,227 227 53,462

1998–99 190 41,658 38 12,349 228 54,007

Total 190 2,07,582 38 44,442 228 2,52,034

JRC: Junior Red Cross; YRC: Youth Red Cross

in schools. Students undertook community levelprojects and dissemination of information on malariaand its control to the community. Each student wasassigned 10 houses to disseminate information onmalaria. Students and residents identified mosquitobreeding sources and undertook intervention (Fig. 8).This included inversion of small or large domestic con-tainers/tanks, introduction of larvivorous fishes, mos-quito-proofing of overflow pipes of overhead tanks,sumps and vent pipes of septic tanks with nylon nets,safe storage of tyres, clearing drain pipes of terracesand lintels and filling up small pools.

The performance of students was evaluated throughexamination. Successful completion of malaria course(as one of the five components taught as optionalsubject under Junior and Youth Red Cross) was es-sential for students to earn 5 marks at higher second-ary level. This helped them to compete better forprofessional courses. To make learning pleasant and

22 IDVC PROJECT PROFILE

interesting, songs, dramas, monologue competitionon malaria themes in schools were organised andawards were given by the Chief Secretary, Goa Gov-ernment and Governor of Goa. In 1999, IDVC field unitassessed cost of the malaria teaching programme inthe schools. The cost per household attended and vis-ited by students worked out to Rs. 50.28 (US $ 1.17)with the major share coming from the community itself.

Health impact assessment of KonkanRailways project

Konkan Railway Corporation has constructed 760 kmlong coastal railway line connecting Roha in Maha-rashtra to Mangalore in Karnataka. Considering thedifficult and challenging terrain through which the rail-ways passes, the project can be appropriately de-scribed as engineering marvel with large number ofmajor and minor bridges, culverts, tunnels, railwaystations, washing yards, etc. Due to heavy rainfall inthe Konkan region and possible obstructions to thenatural watershed by the project, there was lurkingfear in the minds of many that outbreaks of mosquito-borne diseases would be imminent due to projectactivities. Stepping in during the construction phase,IDVC field unit in collaboration with Directorate ofHealth Services, Goa, Konkan Railway Corporationengineers and a team of Nadiad field unit of MalariaResearch Centre carried out detailed surveys in allrailway project sites in Goa. To start with, IDVC field

unit and DHS teams visited all the labour camps lo-cated on 105 km stretch in Goa sector and the entiremigrant labour force was screened for malaria. Simul-taneously their clinical profile was recorded by theDHS. Malaria cases detected were promptly treatedto avert outbreaks. A detailed survey on mosquito-genic potential of the project was carried out along theKonkan Railway alignment and adequacies of crossdrainages were assessed. IDVC field unit put forwardthe following recommendations to the Konkan RailwayCorporation which were accepted (Fig. 9 a,b,c and d).

1. Sloping roof of the railway station and residentialbuildings.

2. Installation of mosquito proof overhead tanks atstation buildings and residential quarters.

3. Construction of septic tanks and soak pits nearstaff quarters and railway stations.

Fig. 9a: Photograph showing efficient drainage system thatwas built along the embankment of Konkan Railway track

Fig. 9b: Mosquito proof overhead tanks built at the railwaystations

Fig. 8: Students preparing to overturn a largediscarded septic tank harbouring

mosquito breeding

23PANAJI

4. Efficient drainage of water at the railway stationand coach washing yards.

5. Filling or demolition of tanks after construction ofmajor and minor bridges, tunnels, etc.

6. Clearance of mud/silt from the mouth of pipe cul-verts and box culverts to ensure smooth flow ofwater.

7. Filling up of depressions near major bridges toavoid stagnation of water.

8. Clearance of drain near the cutting section and themouth of tunnel.

The recommendations were implemented in theentire Goa Sector. Subsequently during operationalphase of the project, a post completion survey wasalso conducted. Based on current findings, a fresh setof recommendations were given which were also ac-cepted by the corporation. The corporation was also

given a set of following recommendations to incorpo-rate in their corporate policy in case of expansion ofthe present project and for the similar future projects.

1. All the future stations, staff quarters and otherbuildings built by the Konkan Railway shall havesloping roofs.

2. Only mosquito proof overhead tanks and flushtanks shall be installed and their overflow pipeswill be fitted with mosquito proof arrangement.

3. Large water tanks including overhead tanks andground water sumps shall always be fitted withmosquito proof lid assembly as per the specifica-tions provided.

4. Septic tanks in the buildings shall be kept hermeti-cally sealed and their vents covered with nylon/iron mesh at all times.

5. The masonry tanks shall be demolished com-pletely after construction so that no opportunity forwater stagnation is provided.

6. No borrow pits shall be created anywhere.7. Buildings and staff quarters to be provided with

mosquito proof wire netting in the doors and win-dows.

8. Larvivorous fishes shall be introduced in waterbodies and tanks along the railway alignment.

A film on the implementation of recommendation bythe Konkan Railways Corporation was prepared bythe Audio-visual division of MRC entitled ‘No Ticket forMosquitoes’ which was released to the nation by theDirector General, ICMR.

Field evaluation of biolarvicide– Bacillusthuringiensis israelensis H-14 strain 164

Field trials with B. thuringiensis israelensis (H-14)were conducted in Panaji, Goa, between April 1991and February 1992 in three types of breeding habitatsof An. stephensi like masonry tanks, curing water inconstruction sites and discarded overhead tanks totest the bioefficacy of the formulation. There was97.8% mortality amongst III and IV instar larvae within24 h of treatment of the curing water. Third/fourth in-stars were not encountered until seven days post-treatment (Kumar et al., 1995). In the masonry tanksalso, the densities of III and IV instar larvae of An.stephensi in the treated tanks were significantly lessthan in the control tanks (t = 5.16, df = 11, p = 0.0002).Mortality among III and IV instar larvae was 100% inthe masonry tanks within 48 h of application. Subse-quently low densities were observed until Day 35 post-

Fig. 9c: Drain was built to prevent water stagnation at themouth of tunnel

Fig. 9d: Construction tank being used for larvivorous fishproduction after completion of work

24 IDVC PROJECT PROFILE

treatment. No pupa was observed until Day 18 of thetest and they remained at low densities till the studywas concluded. Discarded overhead tanks on ter-races were found supporting breeding of An. ste-phensi especially during the monsoon season. A highdegree of mortality was achieved within 24 h post-application. Mortality of III and IV instar larvae reached100% within 48 h of application. In these habitats al-though there was significant reduction in the popula-tion of late instars in the abandoned overhead tanks,pupal production resumed within seven days of post-treatment.

In an another trial in the Sada locality of Vasco-de-Gama, Goa, weekly spraying of B. sphaericus fromApril 1993 to March 1994 at 1 g/m2 in cesspools, cess-pits and septic tanks resulted in a sharp decline in theimmature and adult populations of Cx. quinque-fasciatus (Kumar et al., 1996). Throughout the studyperiod, the per man hour adult densities, percent habi-tat positivity and immature densities were significantlylower in the treated area compared to that of the con-trol area (Fig. 10).

In view of the development of resistance of An.stephensi to DDT, dieldrin and malathion in Goa(Thavaselvam et al., 1993), use of biolarvicides formalaria control was evaluated in a large malaria en-

demic area of Panaji. Weekly application of thebiolarvicide B. sphaericus (strain 101, serotype H5a5b) at the rate of 1 g/m2 in the An. stephensi larvalhabitats, such as curing waters, masonry tanks andsump tanks (under construction) from April to Decem-ber 1993 resulted in sharp decline in the habitat posi-tivity (range 0.13–8%) as compared with rest of Panaji(range 2.2–30.6%) where temephos was used as thelarvicide. B. sphaericus spraying also led to a signifi-cant decline in anopheline densities in positive habi-tats (range 0–7.3/10 dips) as compared with that ofcontrol habitats (range 0.9–53.0/10 dips). Concur-rently, malaria incidence observed in the experimen-tal area (slide positivity rate range 2.3—7.8%; monthlyparasite index range 0.18–1.44) was lower than thecontrol area (SPR range 14.3–25.5%; MPI range1.75–6.12). Thus the impact was clearly discernible onmalaria (Figs. 11 and 12).

Malaria control in Candolim PHC usingbiolarvicides and fish

A severe outbreak of malaria occurred in the coastalvillages of Candolim PHC of Goa in 1993 and furtherintensified in 1994 (Kumar et al., 1998, 1999). The out-break was associated with accelerated constructionactivity with an influx of migrant construction workers.Conventional methods of control (DDT spraying and

Fig. 10: Results of Bacillus sphaericus field trials in Vasco-de-Gama town in Goa. There was a marked decline inper dip density and % habitats positive for Culex quinquefasciatus

25PANAJI

pyrethrum fogging) proved inadequate and alternatecontrol strategies were required. Weekly applicationof B. thuringiensis israelensis @ 1 g/m2 was intro-duced in shallow and small breeding habitats of An.stephensi, while an indigenous larvivorous fish, A.blocki was introduced in major breeding habitats fromJune 1994 onwards. The objective of this longitudinalstudy was to evaluate the effect of Bti and larvivorousfish on An. stephensi and subsequent transmission of

Fig. 12: Impact of Bacillus sphaericus on malaria incidence in experimental area as compared to control area whensprayed @ 1 g/m2 in An. stephensi breeding habitats

malaria in Candolim PHC in Goa. In 1995, the popu-lations of An. stephensi in larger and smaller habitatsdeclined significantly compared with correspondingperiod in the previous year (Fig. 13). Similarly, a sharpdecline in the malaria incidence also occurred in 1995as compared to 1994 (Fig. 14). Comparative analysisof malaria incidence in Candolim PHC and the sur-rounding towns showed that SPR, SFR and parasiteindex in the experimental villages of Candolim PHC

Fig. 11: Impact of Bacillus sphaericus on habitat positivity and per dip density of anophelines in Panajiand their comparison with control area

26 IDVC PROJECT PROFILE

Fig. 14: Impact of intervention measures on the incidence of malaria in Candolim PHC in 1995compared with that of in 1994

declined by 57.3, 82.6 and 81.6%, respectively in1995, but the incidence in two nearby malaria endemictowns (Panaji and Porvorim) increased substantiallyduring 1995 as compared to 1994.

Bioenvironmental control of malaria inMormugao Port—A technology transferproject

This project was initiated in the year 1997 following

Fig. 13: Impact of weekly spraying of B. thuringiensis israelensis (H-14, Strain 164) on anopheline breeding in theconstruction sites in Candolim PHC

serious complaints of mosquito nuisance in the Portcomplex (Fig. 15) during night shifts in spite of sub-stantial cost being incurred for mosquito control. Theproject was sponsored by the Port. Department ofMedical Services and Civil Engineering Department ofthe Port were selected as the partners in implemen-tation of bioenvironmental control of mosquitoes andtransfer of technology to the Port. Till the year 2001,mosquito intervention was done (Fig. 16 & 17) whichled to significant reduction in mosquito populations aswell as malaria cases (Fig. 18). In the year 2002,

27PANAJI

Fig. 15: A view of Mormugao Port Trust

bioenvironmental control technology was transferredto the Port Medical and Civil Engineering Depart-ments. Various components of transfer of technologysuch as constitution of committees, preparatory semi-nars, training on mosquito intervention, mosquitoproofing, blue-print preparation, impact assessment,conduction of surveys, review of the interventions, etc.were done during April 2002 to February 2003 in aphased manner.

Therapeutic efficacy of chloroquine in thetreatment of uncomplicated P. falciparummalaria

Recently, following a standard WHO protocol, a studywas carried out in Panaji, Goa in 2003 and 2004 toassess the therapeutic efficacy of chloroquine in un-

Fig. 16: Photographs showing a variety of breeding sites in theport area (left) and intervention methods used (right)

a

c

e

g

b

d

f

h

Fig. 17: Glimpses of bioenvironmental control of mosquitoes atMormugao Port: (a) Safe storage of ore buckets; (b) Channelisa-tion of masonry tank overflowing water; (c) Sealed septic tankcovers; (d) Vent pipe covered with nylon gauze to prevent mos-quito entry; (e) Newly introduced pre-cast mosquito-proof con-tainer covers; (f) Newly introduced mosquito-proof lid assembly;(g) Informal discussion with engineers and doctors in a technol-ogy transfer workshop; and (h) Workshop delegates at a malar-ia exhibition

Fig. 18: Status of malaria in the port from 1998 to 2001

complicated P. falciparum malaria. Out of 63 patientsenrolled, 51 could be followed-up for 28 days. Thepatients were clinically examined and their bloodsmears were prepared and examined for P. falciparumparasitaemia on Days 0, 1, 2, 3, 7, 14, 21 and 28.Results of the trial showed that 43 (84.3%) of the pa-tients did not respond to the chloroquine and adequateclinical and parasitological cure following treatmentwith chloroquine therapy was observed only in 15.7%of the patients (Fig. 19). Of the chloroquine resistant

28 IDVC PROJECT PROFILE

cases, there was early treatment failure in 12 (23.5%)cases, late clinical failure in 7 (13.%) and late parasi-tological failure in 24 (47.0%) cases. A combination ofsulphadoxine + pyrimethamine and artesunate wasprescribed to such cases who were followed-up tillthey were completely cured. Based on the findings ofthis study, the NVBDCP has withdrawn use of chloro-quine and introduced sulphadoxine-pyrimethamine forthe treatment of uncomplicated P. falciparum malariain Panaji.

Insecticide resistance in mosquito vectors

Monitoring of insecticide resistance in malaria vectorsis a priority area of operational research relevant to theneeds of the NVBDCP. Susceptibility studies carriedout in 1993 revealed that malaria vector– An. stephe-nsi, filaria vector– Cx. quinquefasciatus and denguevector– Ae. aegypti had developed resistance to DDT,dieldrin and malathion in Panaji (Thavaselvam et al.,1993).

Susceptibility of An. stephensi was evaluated in 2003–04 in North Goa district using diagnostic papers ofDDT (4%), malathion (5%) and deltamethrin (0.25%)following WHO procedure and using standard kit. Twostrains of An. stephensi from malaria endemic areassuch as Panaji and Candolim-Calangute were rearedin the field unit insectary. Knockdown effect of the in-secticides and mortality after 24 h post-exposure wererecorded. The findings are shown in Fig. 20.

Using An. stephensi Panaji strain, 100% knockdown

was observed after 1 h exposure of deltamethrin pa-pers although mortality was 89.4% after 24 h of hold-ing. With An. stephensi Candolim strain, 99% knock-down was observed after 1 h exposure, while cor-rected mortality after 24 h was 88.9%. This indicatesthat both the strains were susceptible to deltamethrinalthough there was an indication of vigour toleranceas indicated by about 10% resistance in the teststrains. With DDT papers, An. stephensi Panaji strainshowed 48% knockdown after 1 h exposure althoughmortality was 10.5% after 24 h post exposure. An.stephensi Candolim strain showed 33% knockdownafter 1 h exposure, while mortality at 24 h post-expo-sure was 11%. The results suggested that both strainsof An. stephensi are highly resistant to DDT.

With malathion, knockdown of An. stephensi Panajistrain was only 1% after 1 h exposure and there wasno mortality observed after 24 h post-exposure. An.stephensi Candolim strain had 5% knockdown after 1h of exposure, while corrected mortality after 24 hpost-exposure was 10.5%. The results showed thatPanaji strain has become completely resistant tomalathion. Even Candolim strain showed high resis-tance to malathion. There was hardly any knockdowneven after 1 h of exposure in both the strains.

Study on biting, resting behaviour andincrimination of vectors

Mosquito collections were made from three malariaendemic urban and suburban areas of Goa. In well-built houses, 67 h of collections did not yield a singleAn. stephensi mosquito, although other species wereencountered. However, collections from constructionsites and workers’ huts for 151 h yielded, 38 An. ste-phensi females resting in 15 types of sites at a heightvarying from 30 cm to 2.4 metres besides other mos-quito species. In all, 11 mosquitoes were caught rest-ing on unplastered surfaces, four each on plasteredsurface and on bamboo and wood surfaces, three onmetal surfaces and four on others, thus showing ahigh variability for resting. Of 37 mosquitoes tested forthe presence of circumsporozoite protein (CSP) by anELISA technique, one was found to be P. falciparumCSP positive (Sumodan et al., 2004). This study sug-gested that IRS cannot be of much use in this areaand selective larviciding would be the best choice forvector control.

A longitudinal study on biting behaviour of vectorsconducted on human baits from 1800 to 0600 hrs in75 all night mosquito collections in Goa in 1991

Fig. 19: Therapeutic response of P. falciparum malaria patientsto chloroquine in Panaji Goa. ACPR – Adequate clinical andparasitological response, ETF – Early treatment failure, LCF –Late clinical failure, LPF – Late parasitological failure, TF – Totalfailure

29PANAJI

Fig. 20: Percentage knockdown and mortality respectively in Panaji and Candolim strains ofAn. stephensi when exposed to diagnostic doses of deltamethrin (0.25% for 1 h),

DDT (4% for 1 h) and malathion (5% for 1 h)

showed that six mosquito vector species— An. ste-phensi, Cx. quinquefasciatus, Cx. vishnui, Cx. pseu-dovishnui, Cx. tritaeniorhynchus and Ae. aegyptiexhibit differential feeding pattern during differentphases of night. Weather conditions were also foundto influence feeding activity during different seasons.The peak biting of An. stephensi was observed be-tween 2200 and 2400 hrs when 69% of biting wasobserved. The filarial vector Cx. quinquefasciatus bitthroughout the night although peak biting was observedbetween 0100 and 0200 hrs. Peak biting time of Cx.vishnui was between 2300 and 2400 hrs and that of Cx.tritaeniorhynchus it was from 2400 to 0100 hrs. Ae.aegypti was predominantly crepuscular and its bitingceased at 2200 hrs although peak biting was observedbetween 1800 and 1900 hrs (Kumar et al., 1995).

Larvivorous fish surveys

Extensive surveys of larvivorous fishes were con-ducted covering ponds, backwaters, streams, lakes,paddy fields submerged under water, rivers/rivuletsand irrigation canals in all parts of Goa (Sumodan andKumar, 1998). Fifteen species of fishes were recordedsuch as Aplocheilus blocki, A. lineatus, Rasbora

daniconius, Puntius vittatus, P. amphibious, P. mela-nopyx pradhani, Macropodus cupanus, Danio aequi-pinnatus, Osteochilichthys nashii, HypselobarbusDobsoni, Oreochromis mossambicus, Theraponjarbua, Heteropneustis sp., Etroplus suratensis andMugil cephalus. Their habitat wise distribution wasstudied and density was recorded. In controlled ex-periments, mean consumption of Cx. quinquefasci-atus larvae varied from 62.5 to 736 per fish by differentspecies. On the basis of their extensive distribution,availability and usefulness, A. blocki (mean consump-tion: 102.6 larvae per day/per fish) and R. daniconius(mean consumption: 464.3 larvae per day/fish) wererecommended for malaria control operations in Goa.

Evaluation of rapid diagnostic tests

Field evaluation of rapid diagnostic tests was done todetermine their efficacy and sensitivity (Kumar et al.,1996, 2000). The kits evaluated were ICT-Pf, Binax,Para-check®-Pf, Parascreen, Paramax and Falcivax.The field station also carried out quality control test onParacheck®-Pf consignment procured by RITES IndiaLtd. for NVBDCP’s World Bank funded EnhancedMalaria Control project.

30 IDVC PROJECT PROFILE

Isolation of mosquito pathogenic bacillifrom Goa

Eight isolates of mosquito pathogenic bacilli were iso-lated from soil samples collected under sterile condi-tions from different parts of Goa devising a newprotocol which was simple and avoided cumbersomeprocedure of isolation (Kumar et al., 2000; Dhindsa etal., 2002). Strains KSD 4, 7 and 8 which showed prom-ising results during preliminary bioassays were furtherprocessed for biochemical characterisation for iden-tification and bioassays against mosquito larvae.Commercial formulations of B. t. israelensis H-14strain 164 and B. sphaericus (B101) H5a 5b wereused as control for comparison. Scanning electron mi-

crographs of all the new isolates and control strainswere prepared.

Training programmes

IDVC field unit imparted training to participants fromdifferent departments, students of different schools,colleges, Goa University, Nursing school, multi-pur-pose workers, laboratory technicians, officials of vari-ous departments, doctors, civil engineers, sanitaryinspectors, construction supervisors, teachers, build-ers and contractors, National Social Service volun-teers and officers, conservators of forests, artists,municipal workers, etc.

�