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TRANSCRIPT
Cost-effectiveness of Aedes aegypti control programmes; participatory versus vertical.
A. Baly a, M.E. Toledoa, M. Boelaertb, A. Reyesa, V. Vanlerbergheb, E. Ceballosc, M. Carvajalc, R.
Masoc, M. La Rosac , O. Denisc, P. Van der Stuyftb.
aInstituto de Medicina Tropical "Pedro Kourí"
Department of Epidemiology, Autopista Novia del Mediodia Km 6½, La Lisa, Ciudad de La
Habana. Cuba
Telephone: 0053-7 2020652
Mail resp: [email protected], [email protected], [email protected]
bEpidemiology and Disease Control Unit, Institute of Tropical Medicine, Nationalestraat 155,
2000 Antwerp, Belgium
Tel : 0032-32.47.62.86, Fax : 0032-32.47.62.58
Mail resp: [email protected], [email protected], [email protected]
cUnidad Provincial de Vigilancia y Lucha Antivectorial, Santiago de Cuba, Cuba.
Provincial Center of surveillance and vector control, Santiago de Cuba; Avenida Garzon,
Santiago de Cuba
Mail: [email protected]
Corresponding author:
Lic. Alberto Baly Gil, MA
Department of Epidemiology, Institute of Tropical Medicine “Pedro Kouri”, Autopista Novia del
Mediodia Km 6½ La Lisa. Ciudad de La Habana. Cuba
Telephone: 0053-7 2020652
Mail resp: [email protected], [email protected]
Abstract word count: 169 words
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Text word count: 3977 words
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ABSTRACT
We conducted an economic appraisal of two strategies for A. aegypti control: a vertical versus a
community-based approach.
Costs were calculated for the period 2000-2002 in 3 pilot areas of Santiago de Cuba where a
community intervention was implemented, and compared to 3 control areas with routine vertical
programme activities. Reduction in A. aegypti foci was chosen as the measure of effectiveness.
Pre-intervention number of foci (614 vs. 632) and economical costs for vector control (US$ 243
746 vs. US$ 263 486) were comparable in both the intervention and control areas. During the
intervention period (2001-2002), we observed a 13% decrease in recurrent costs for the health
system. Within the control areas these recurrent relative costs remained stable. The number of
A. aegypti foci in the pilot areas and the control areas fell by 459 and 467 respectively. The
community-based approach was more cost effective from a health system (US$ 964 vs. US$
1.406 per focus) as well as from society perspective (US$ 1.508 vs. US$ 1.767 per focus).
Keywords: Cost effectiveness analysis, Aedes aegypti, control programme, community based
programme, dengue, Cuba
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INTRODUCTION
Ineffective vector control, urbanization, and increased air travel have led to a resurgence of the
mosquito Aedes aegypti in Latin America and to the emergence of dengue as a public health
problem (Gubler and Casta-Valez, 1991). At present, vector control and early detection and
control of outbreaks are the only strategies available to reduce the impact of dengue (Gubler
and Casta-Valez, 1991). Ultimately, the prevention of dengue epidemics will depend on long-
term vector control. The successful Aedes aegypti control campaigns in the Americas during the
1950s and1960s, had, by 1972, achieved the eradication of this mosquito in 21 countries within
the region. However, by the end of the seventies, the majority of countries suffered re-
infestation because financial support for control programmes had dwindled over time and, in
some cases, was even abandoned (Rodriguez, 2002). It is commonly accepted that the
participation of the community in the vertical control programme activities is critical to achieve
sustainable and cost-effective vector control (Gubler, 1989; Liborio et al., 2004). No data exists
on the total expenditure committed to dengue prevention and control in the Americas. This can
be explained by the absence of a unified control structure and because manpower and supplies
are usually not exclusively committed to dengue control. Typically, during epidemics,
expenditure by governments and international donors increases dramatically, especially on
insecticides, whereas between epidemics there is little money or resources available for routine
control operations (PAHO, 1994). It has been estimated that, in 25 endemic countries, only
US$ 331 million and US$ 671 million was spent in 1996 and 1997 respectively on routine vector
control (A blue print for action for the next generation, 1999), when the required budget was
some US$ 1.6 billion.
Also there is little evidence on the cost-effectiveness of larval control (McConnell and Gubler,
2003) and of recently promoted strategies of dengue health promotion that adopt a behavioralist
approach to achieve behavioural changes (Parks and Lloyd, 2004) .
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This study presents a cost-effectiveness analysis of two alternative strategies for Aedes aegypti
control: a classical vertical vector-control program and a community based intervention
integrated in the vertical program. Whereas the former is managed in a top-down manner, with
planning and managerial decision making all centralised at the national level, the latter involved
the local communities in the planning and management of different control activities at local
level (Toledo et al., 2006b). Both strategies were implemented in parallel in Santiago de Cuba,
Cuba, during 2001 and 2002.
Material and Methods
Background
Dengue in Cuba occurs in outbreaks (Kouri et al., 1989; Pelaez et al., 2004; Valdes et al.,
1999),that must be controlled at cost considerably greater than that of routine control
programmes. Cost of control measures for the 1981 nation-wide outbreak and the 1997
outbreak in Santiago de Cuba were estimated at respectively US$ 103 million and US$ 27
million (Guzman et al., 1992; Valdes et al., 2002). By 1981 the Cuban government had already
launched a nationwide Aedes aegypti control programme which is managed by the Ministry of
Health (MOH). Campaign workers at primary health care level perform the main vector control
activities. These procedures comprise; source reduction through the periodic inspection of
houses, adding larvicides to water storage containers, selective peri-focal spraying (application
of adulticide in a radius of 100-300m around the detected foci) against adult mosquitoes, quality
control, health education and the enforcement of mosquito-control legislation (Toledo et al.,
2006b).
Despite high-level political support, adequate financial resources and high coverage, the
programme did not manage to sustain reductions in vector infestation levels across all areas
(house index less than 1%). To highlight a specific example, by 1987, the eastern province of
Santiago de Cuba, had succeeded in eradicating the vector but, by 1992, began to suffer from
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re-infestation (Valdez et al., 1999). Difficulties with the reliability of the water supply led the
population to store water in all kinds of containers, many of them in poor condition or without
covers. Though campaign workers treated these vessels with larvicides, constant cleaning
soon negated the effect and rendered the procedure pointless and wasteful (de la Cruz et al.,
1999).
Study site
We conducted a cost-effectiveness study in the city (or Municipality) of Santiago de Cuba.
Santiago de Cuba boasts a population of 470 000 inhabitants who are cared for by a dense
network of family medical practices staffed by family doctors and nurses organized into nine
health areas. In 2000, the Provincial health authorities decided to develop and test a strategy by
introducing community participation into the routine vector control programme. Twenty family
medical practices within three health areas suffering similar A. aegypti infestation levels were
randomly selected for this novel approach. An identical number of control practices were
earmarked within three comparable areas of the same municipality. A full description of the
intervention study is given elsewhere (Toledo et al., 2006b).
Study type, time horizon and description of strategies
We carried out a cost-effectiveness analysis from a number of different perspectives; from that
of the health system provider (establishing the total provider cost for vector control as well as
the contribution from the primary health care services), from that of the vertical programme
(provider cost of vector control only), from a community perspective (estimating the value of
unpaid time given by all actors at the community level, including unpaid time contributed by
health and vector control personnel) and from that of the society (Health system and
community). Both the time and analytical horizon ran for two years (2001-2002) which coincided
with the implementation period of the community-based intervention scheme. A full description
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of the two strategies follows.
1. Vertical vector control programme (control areas)
The national programme carried out the regular A. aegypti control activities throughout 2000.
From early 2001 these activities were stepped up in the light of a dengue outbreak in Havana.
Intensified focal and peri-focal larval control, blanket spraying for mosquito adulticiding, and
replacement of defective water tanks were among the measures taken. The intervals between
house inspection cycles required for larval control were reduced from 22 to 7-11 days. Finally,
local leaders were trained in the delivery of MOH-sponsored IEC advice about dengue and the
need to promote environmental risk reduction (Toledo et al., 2006b).
2. Community participation strategy (intervention areas)
An alternative dengue control strategy was introduced at the end of 2000 in order to encourage
active community participation in disease prevention in the regular A. aegypti control
programme. An external research group from the Institute of Tropical Medicine “Pedro Kourí”in
Havana, set up in coordination with the health authorities of Santiago, a local researchers team
that was to become in charge of guiding the project. The external and local teams jointly
designed through a participative process the intervention, based on formative research. (Toledo
et al., 2006)
The main goal of the intervention was to mobilize the community to become involved in all
stages of Aedes aegypti control, from problem identification, through planning and
implementation and up to the final evaluation.
A decision was taken to use the primary health care network as the vehicle for this new initiative.
In early 2001 the family medical practices involved decided to create their own Community
Working Groups (CWG). Across the whole intervention-area, 20 such CWGs were created; one
for each community that is served by a family medical practice.
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The strategy was truly community-based, and can be assimilated to other “community-directed”
initiatives Though the Community Working Groups were organized around the family doctor’s
practices, the “direction” given by the health services was limited to the sharing of the
information about the importance of dengue control. Once the CWG was formed including
formal and informal community leaders and volunteers as well as interested medical and vector
control staff, complete autonomy was granted to the group to establish priorities and to devise
action plans. No financial incentives were offered to members. They identified main health
problems and felt needs, elaborated, implemented and evaluated their action plans that varied
widely, from the transformation of garbage belts into vegetable gardens to the repairing of
broken water pipes, sealing of basements and manufacturing of lids for water containers. The
necessary equipment and materials were provided free-of-charge by local government whilst
members of the community gave their labour for nothing. All these activities were accompanied
by a locally-designed, public health education strategy, which aimed to mobilize the population
and to promote healthy behavior. (Toledo et al., 2006b)
Data collection and analysis
Costs
The economic costs of both strategies were estimated for fiscal years 2000 (before the
intervention), 2001 and 2002 (during the implementation). Source of cost and activity data were
the Cuban accountancy system for health (CONUS-Contabilidad única del sistema de salud)
and the Cuban health information system. Costs inputs were itemized and allocated according
to the WHO Methodology (Johns et al., 2003). Because of the labour intensive nature of both
the classical control programme and complementary community-based activities, the principal
costs are virtually all recurring, including those which relate to the salaries, consumables and
notional hourly pay for time actually given free by the community.
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The labour cost of the campaign workers, in both control and intervention areas were derived
from the bookkeeping records maintained in each of the health areas. It includes the wages paid
to the workers involved in larval control, adult mosquito control, quality control and to the
supervisors of those activities. We have also included the share of the salary paid to primary
health care workers (doctors, nurses, epidemiologists, technicians, health managers) who gave
part of their time to the vector control programme or to the community participation strategy.
Semi-structured interviews were carried out in order to estimate the proportion of staff time
allocated to each type of activity.
The costs of consumables used for larval control and spraying were determined by multiplying
the average value of products used per house for each of these activities by the number of
houses inspected or sprayed in a single year. This data was collected by non-participant direct
observation of vector control activities by trained personnel on the one hand and from
accounting departments and the epidemiological information systems on the other hand.
The cost of training and social communication was estimated from the respective reports and
registers of both the vertical programme and the intervention project. It includes cost of
materials, salaries of teachers and other personnel and estimated cost for trainee time based on
the government study allowance rate.
Operating expenses included food, travel allowances, fuel and lubricants for vehicles, electricity
and repair of spraying equipment. These costs were estimated from direct observation,
interviews, and from an examination of the bookkeeping records of the Provincial and Municipal
accountancy departments.
Capital costs included vehicles and equipment. Annual capital goods depreciation was
calculated using the linear method: 5 years of useful life and a discount rate of 6%. The cost of
buildings was not included because the information was not available and a local market does
not exist in Cuba to consider replacement costs. In any event the depreciation cost of these
capital items relative to the total cost of the programme is very small because of the
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programme’s labour-intensive nature.
We estimated the value of unpaid community work by valuing it at the same rate that a similar
type of employment would be reimbursed in the government sector. We also applied this rate to
the additional time that health professionals volunteered to work over their contractual hours in,
for example, the elimination of environmental risks (potential breeding site of any kind) , and
cooperation with campaign workers, intersectoral coordination, and programme monitoring. In
order to estimate the value of the “community contribution” we surveyed and interviewed health
care personnel, campaign workers, health promoters together with members of households. In
addition we reviewed community action plans and reports drawn up by health promoters and
local leaders. We did not include the cost of free of charge equipment and materials provided
by local government. Equipment is not rented by the government therefore the capital
depreciation because of the time used was almost zero. The kind of material supplied varied
substantially from community to community, but overall the amounts were very small at any rate,
so we decided not to include them in the calculations.
The cost per item was calculated for both the baseline (2000) and for the intervention period
(2001-2002, annual and cumulative), and was also expressed as a percentage of the total cost.
The costs in Cuban pesos were standardized at 2002 prices using a GNP implicit deflator (Cuba:
Evolución económica, CEPAL, 2004) and were then converted to the $US at the official
exchange rate of 1 peso= 1 $US.
We computed the total economic cost to the society, the cost to the health system and to the
vector control programme (including larval control-which include inspection and larvicide’s
application, larval quality control, larval operational cost, training and administrative share), and
cost-per-inhabitant covered.
We determined inputs where the intervention had a higher or lower cost in comparison with the
control area. We calculated the absolute and percentage cost differences between the two
strategies, by each cost input estimated, using the procedure proposed by Reynolds and
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Gaspari (1986).
Effectiveness
The intervention study (Toledo et al., 2006b) used several different measures to analyze
effectiveness: entomological indicators extracted from routine data collection (number of foci,
house index, changes in location of main breading sites) and behavioral change indicators
(numbers of correctly covered tanks, unprotected artificial containers, water containers
protected by larvicide). We used the reduction in number of foci, defined as any kind of
container containing a larval stage of Ae. aegypti, as effectiveness measure. The reduction was
calculated for three discrete periods: 2001 versus 2000 (first year of intervention), 2002 versus
2001(second year of intervention) and 2002 versus 2000 (whole period of intervention)
Cost-effectiveness
Cost-effectiveness was calculated for three periods (2000-2001, 2001-2002 and 2000-2002).
The overall annual costs were divided by the reduction in number of foci for the corresponding
period. Incremental cost-effectiveness for 2002-2000 was calculated by dividing the difference
in total cost by the difference in the overall reduction in the number of foci between the two
strategies.
RESULTS
Cost Analysis
The greater part of the budget (60%) committed by the municipality as a whole to the vertical
programme was spent on wages (Table 1), because of the labour intensive character of the
work. Following management decentralization in 2001, a portion of the capital stock was
transferred to other governmental agencies, hence the substantial decrease in the value of fixed
assets from the previous year.
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From 2001, high vector infestation levels led to shorter programme cycles (the time interval
between house inspections); from 22 to first, 11 and subsequently, 7 days, with a concomitant
increase in the work force employed. There was a corresponding increase in total salary cost;
consequently the cost per inhabitant (p.i.) grew from $US 13 in 2000 to $US 24 in 2002.
Both the intervention and control areas were comparable with regard to the number of houses,
infestation level, number of inhabitants per house, and environmental risk (Table 2).
The figures in table 3 show that the activities of the vertical control programme were similar in
both areas, leading to comparable expenditure during the baseline period. Furthermore, if the
costs of the primary health care team and the community contribution are excluded, the
relationship (expressed as a percentage) between recurrent and capital costs and the total cost
are similar to the ones reported in table 2. This corroborates our baseline cost estimations.
The accounts show that there was an absolute increase in recurrent costs in both areas
between 2001 and 2002.
However, within the intervention area, the share of recurrent costs relative to the total cost
decreased from 76.3 % to 63.7 %. There was also a shift from financial to economic cost
because community costs increased from 23.5 % to 36.1%. Within the control area the cost
breakdown by item remained the same throughout the study period (Figure 1).
While p.i. costs were comparable prior to the intervention (2000), by 2002 the economic cost p.i.
had reached $US 32 in the intervention area and $US 41 in the control area. In the same year
the financial cost to the health system, vertical programme, and larval control programme were
$US 20 p.i., $US 16 p.i. and US$ 7 p.i. respectively. In the control zone these costs were higher:
$US 32, $US 28 and $US 12 respectively (Figure 2).
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The additional cost to the Health System was US$ 214 198 (48% higher) in the control area
compared to the intervention area (Table 4). All provider cost items, except for social
communication costs were higher in the control area. However, the cost to the community was
48.1% higher in the intervention area.
Table 5 illustrates the amount of time invested in the intervention area by the different kind of
actors involved, during 2 years of intervention. Most of the time was invested in surveillance of
intra- and extra- domiciliary risks (132 600 hours- 36.3%), followed by environmental risks (100
830 hours-27.6%), community sanitation (65 080 hours- 17.8%) and, finally, planning and
evaluation of community activities (39 912 hours-10.97%).
Effectiveness and Cost effectiveness
At baseline intervention and control areas reported 614 and 632 foci respectively. These
numbers decreased in 2001 to 272 and 274 respectively and further in 2002 to 155 and 157. In
overall during the intervention period (2001-2002) both zones showed a similar reduction in
number of foci: 459 in the intervention and 467 in the control area (Table 6). Community based
intervention was more cost-effective from the point of view of society as a whole (Table 6). It
was also more cost-effective from both the health system and the vertical programme
perspective. In both areas, the cost-per-focus eliminated was lower in 2001 in comparison with
2002. From the point of view of the health system, vertical programme and society (Health
System and community), the incremental cost of eliminating one additional focus was much
higher in the control area than in the intervention area. However the cost was con concomitantly
lower from the community point of view in the control areas.
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DISCUSSION
This study shows that in Santiago de Cuba the dengue control programme that integrated a
community based intervention strategy was more cost-effective than an intensive vertical
programme alone. From an overall health system perspective the former appears to be a good
investment. However, policy makers should realize that community involvement in vector control
is not a “free ride” and carries a substantial opportunity cost in terms of volunteer time spent on
control. It is vitally important to acknowledge the substantial investment in health made by the
community in the form of unpaid labour contributed to vector control activities. At the baseline
both intervention and control zones in our study were directly comparable and there were no
differential external influences for the duration of the study. It is fair to assume, therefore, that
equivalent reductions in the number of foci was solely attributable to relative effectiveness. Any
attempt to evaluate interventions of this type presents a number of difficulties such as
measuring effectiveness, valuing fixed- variable costs and diminishing returns to scale.
After the 1997 epidemic in Santiago de Cuba, no autochthonous cases of dengue were reported
by the national surveillance system. Therefore effectiveness of vector control interventions
cannot be determined by the follow-up of dengue specific morbidity and mortality (Guzman et al.,
2006). Entomological indices (House, Breteau and Container) are used as surrogate markers of
epidemic risk, but the functional relationship between the index scores and the occurrence of
dengue outbreaks is not well known. Moreover, their sensitivity when used to evaluate
community based strategies has been questioned (Kay and Vu, 2005). In our study the most
frequently found larval breeding sites found, were the ground water storage tanks that are kept
indoors or elsewhere on the premises close to the house. Their infestation is directly related to
the behavior of the population: whether they are kept uncovered and/or treated with larvicides
(Toledo et al., 2006a). A reduction in the entomological indices for these specific containers
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might possibly offer a better measure of the effectiveness for community-based interventions.
However only a small proportion of ground tanks registered positive at baseline in our study (in
line with the general indices), making the unit cost of any reduction achieved unstable and
difficult to interpret.
Final-outcome measures such as DALYs or QALYs are recommended for the cost-effectiveness
analysis of health promotion programmes (Haddix and Teutsch, 2003). Ranking competing
alternatives on the basis of cost-effectiveness ratios constructed from surrogate markers has
been questioned, but in studies like ours where there is no alternative, their use is justified
(Haddix and Teutsch, 2003; Haddix and Teutsch, 1999).
We have estimated that the 2002 financial cost of the A. aegypti control programme in Santiago
amounts to approximately $US 16 000 and $US 28 000 per 1000 inhabitants for the intervention
and control areas respectively. Shepard et al. (2004) has recorded the costs of control
programmes in several different countries analyzed per 1000 inhabitants: $US 15 in Indonesia
(1998), $US 81 and $US 188 in Thailand (1994 and 1998), $US 204 in Malaysia (2002) and
$US 2.400 in Singapore (2000). For 17 Caribbean islands (1990) it ranged from $US 140 to
$US 8.490. Our estimates seem very high, but it is difficult to compare them with those
previously reported, since no information was given on the coverage or intensity of these
programmes nor of the background epidemiological situation.
McConnell and Gubler (2003) has demonstrated, based on mathematical modelling of dengue
transmission data from Puerto Rico, that emergency larval control activities (without an early
warning system) are more cost-effective than doing nothing if $US 6 or less is spent p.i. In our
intervention area, during 2002, the cost of the routine larval control was about $US 7 p.i. (in the
control area it reached $US 12 p.i.). These numbers come close to the threshold proposed by
McConnell which suggests that the control activities implemented in Santiago were worthwhile.
In our study, the incremental cost incurred by the vertical programme in order to eliminate one
additional focus is very high when compared with a community based approach. This indicates
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that from a health system perspective, the community-based intervention can produce savings
which might then be used to finance other control programme activities (dengue-related or not)
or to address direct causes of vector proliferation such as water supply problems.
Community-based strategies are generally difficult to implement and it often takes time before
their impact becomes apparent. This discourages governments from investing time, money and
human resources to develop such strategies (Winch et al., 1992). On the other hand, they are
sometimes seen as attractive low-cost alternatives to vertical programmes (Ugalde, 1985).
From the community’s point of view, we should consider the opportunity cost of using unpaid
volunteers to implement certain programme activities.
Moreover, both the community based strategy and the vertical programme were both less cost
effective in 2002 compared with 2001, probably due to diminishing returns of scale. Over time,
both require greater and greater efforts to eliminate each additional focus, and the problem-
solving capacity required either stretches community resources or the programme budget. This
phenomenon may have a negative effect on sustainability.
We may conclude that the described community-based intervention in Aedes aegypti control,
when intertwined with the vertical control programme appears the superior strategy. Even
though entomological indices reported by national control programme are very low in Cuba,
dengue outbreaks occurred with this low level of infestation (Pelaez et al., 2004; Sanchez et al.,
2006).Therefore these findings can be useful for the health decision making in terms of the
resource allocation for the vector control programmes of the other countries Whether this
remains the case in the long run, in particular once Aedes infestation has been reduced to very
low levels must be addressed by future studies.
Conflicts of interest statement
The authors have no conflicts of interest concerning the work reported in this paper.
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Acknowledgements
We gratefully acknowledge the role played by the health sector staff involved in the dengue prevention and control activities. We also thank the people of Santiago de Cuba who participated in the study. The study was partially funded through the framework agreement between the Institute of Tropical Medicine and the Belgium Directorate-General for Development Co-operation, project 95900.
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Figure legends
Figure 1: Relative costs (US$ constant 2002) at baseline and during implementation periods in
the intervention and control areas. Santiago de Cuba. 2000-2002.
RECURRENT COST
CAPITAL COST
COMMUNITY COST
Figure 2: Cost per inhabitant (US$) and per year in the intervention and control areas. Santiago
de Cuba. 2000-2002.
Economic cost
Health System cost
Vertical Programme cost
Larval Control cost
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22
1
Intervention at baseline 2000
76.3%
0.2%
23.5%
Control at baseline 2000
77.0%
0.2%
22.8%
Intervention 2001-2002
63.7%
0.2%
36.1%
Control 2001-2002
79.3%
0.3%
20.4%
Fig. 1 Relative costs (US$ constant 2002) at baseline and during implementation periods in the
intervention and control areas. Santiago de Cuba. 2000-2002.
US$ constant 2002
2000 2001 2002 total 2000 2001 2002 total
intervention control
90
80
70 60
50
40
30 20
10
0
Fig. 2 Cost per inhabitant (US$) and per year in the intervention and control areas. Santiago de Cuba. 2000-2002
2
Table 1 Total Cost (US$1) of the vertical Aedes aegypti control program for covering the whole Municipality Santiago de Cuba. 2000-2002
ITEM 20002 20012 20022 Total2 % Recurrent cost 6 212 607 7 066 096 11 031 153 24 309 856 99,7 Personnel 4 685 441 4 268 208 5 623 337 14 576 986 59,8 Training 25 661 20 530 12 399 58 590 0,2 Supplies 894 762 668 013 1 011 693 2 574 467 10,6 Communications 15 468 19 868 33 046 68 382 0,3 Transport 68 516 882 470 929 944 1 880 929 7,7 Operative costs 522 758 1 207 008 3 420 733 5 150 499 21,1 Capital depreciation 57 265 13 368 14 555 85 188 0,3 Total 6 269 872 7 079 461 11 045 706 24 395 039 100 Cost per inhabitant 13 15 24 52 -
Source: Accountancy of the Health department(Municipality level) 1US$ constant 2002 2All numbers were rounded to the next digit
3
Table 2 Characteristics of intervention and control areas before the intervention. Santiago de Cuba 2000
Baseline information INTERVENTION AREA
CONTROL AREA
Difference (95%CI)
Number of houses
2400 2600 -
Number of house blocks
48 49 -
Average number of subjects per house
4,8 4,2 0,6(-0,5 - 1,2)
Average number of container, for water storage per house
8,5 7,9 0,59(-0,1 - 1,3)
Yearly number of Aedes aegypti foci detected
614 632 -
Principal breeding site Ground tanks for water storage
(indoor)
Ground tanks for water storage
(indoor)
-
Median container index (95%CI)
0,20(0,1 - 0,37) 0,3(0,28 - 0,34) *
Median house index (95%CI)
1,23(0,7 - 2,6) 2,08(1,91 - 2,43) *
Main behavioral risk factors • Houses with incorrect use of
larvicide • Houses with unprotected
artificial containers • Houses with badly covered
containers for water storage
45,6 %
61,9 %
70,0 %
55,2%
60,0%
69,6%
9,7% (-0,8 - 19,8)
1,9%(-8,1 - 12,0)
0,4%(-10,0 - 9,0)
* no differences; because overlap of confidence intervals
4
Table 3 Economic costs (US$1) per year in the intervention and control areas. Santiago de Cuba. 2000-2002.
Intervention area2 Control area2
INPUTS At baseline
2000
running cost/year
2001
running cost/year
2002
Total 2001-2002
At baseline
2000
running cost/year
2001
running cost/year
2002
Total 2001-2002
RECURRENT COST 185 985 210 714 230 340 441 053 202 943 296 512 358 064 654577
Personnel 117 289 129 053 154 699 283 753 127 706 189 932 236 117
426 049
VectorCampaign 90 471 92 885 113 182 206 067 101 188 141 664 180 349 322 013
Primary health care 26 818 36 168 41 518 77 686 26 518 48 268 55 768 104 036
Supplies 17 354 16 077 16 422 32 499 19 542 24 579 30 794 55 373 Training and social Communication 6 161 15 394 12 417 27 812 5 877 6 845 11 129 17 973
Operating cost 45 181 50 189 46 801 96 990 49 818 75 157 80 025 155 182
CAPITAL COST 458 477 952 1 429 468 749 1354 2 103
COMMUNITY COST 57 303 113 318 136 490 249 808 60 075 94 552 74,077 168 629
TOTAL COST 243 746 324 509 367 782 692 290 263 486 391 813 433 496 825 309 1 US$ constant 2002 2 All numbers were rounded to the next digit
5
Table 4 Absolute and percentage cost (US$1) differences by each cost input estimated
during the intervention period. Santiago de Cuba. 2001-2002
Absolute difference between intervention
and control areas percenntage difference
Inputs where the intervention costs less Recurrent cost -213523,8 -48,4 Personnel -142296,3 -50,1 Vector Campaign -115946,3 -56,3 Primary health care -26350,0 -33,9 Supplies -22874,0 -70,4 Larval control -7382,5 -49,5 Spraying -15491,5 -88,1 Operating cost -58192,0 -60,0Capital cost -674,0 -47,2 Vehicles -623,0 -85,7 Equipment -51,0 -7,3
Inputs where the intervention costs more Training and social communication +9838,5 +54,7
COMMUNITY COST +81179,0 +48,1TOTAL -133018,8 -19,2
1 US$ constant 2002
6
Table 5 Average time (in hours) over two years per kind of social actor for each type of activity and total time inverted in the community participation components of the Aedes aegypti control programme intervention. Santiago de Cuba, (2001-2002)
Activities / Social actors Primary Health Care team3
Campaign worker3
Health promoter3
Community Health
Worker4
Household Member4
Total1 %
Planning and Evaluation of Activities (bi monthly CWG meeting, community meeting) 96 96 600 89,3 20 39 912 10,9Surveillance of environmental risk(outdoor) 192 900 800 118,3 50 100 830 27,6Surveillance of risk behaviours(indoor) 260 1100 1200 176,7 48 132 600 36,3Community Sanitation 54,5 100 100 90 40 65 080 17,8Intersectoral Coordination 120 108 120 72 - 17 006 4,7Administration 88 89 80 - - 4 299 1,2Research and training2 74 96 96 - - 5 462 1,5Total1 38 124 18 137 8 988 90 140 209 800 365 189 100
1 sum of all time used by all involved actors 2local researchers, excluding research team from IPK 3 Health system workers 4 Communitarian actors
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Table 6 Cost effectiveness ratios and incremental cost effectiveness ratios for participatory and vertical Aedes aegypti control. Santiago de Cuba. 2001-2002
Perspective Intervention area Control area Total cost Reduction Cost-effectiveness
ratio1 Total cost Reduction Cost-
effectiveness ratio1
Incremental cost per focus eliminated
Health System • During period
(2001) (2002) • All (2001-2002)
211 191 231 292
442 483
342 117
459
617 1 977
964
297 261 359 419
656 680
358 109
467
830 3 297
1 406
26 775
Vertical Program
• During period (2001)
(2002) • All (2001-2002)
175 023 189 774
364 796
342 117
459
512 1 622
795
248 993 303 651
552 644
358 109
467
696 2 786
1 183
23 481
Community
• During period (2001)
(2002) • All (2001-2002)
113 318 136 490
249 808
342 117
459
331,3 1 166
544
94 552 74 077
168 629
358 109
467
264 680
361
-10 1472
Society
• During period (2001)
(2002) • All (2001-2002)
324 509 367 782
692 291
342 117
459
948,81 3 143
1 508
391 813 433 496
825 309
358 109
467
1 094 3 977
1 767
16 628
1US$/eliminated focus. US$ constant 2002 2 In favor of the control area
8