i1o
Regional
9tafus
of
Malaria
in
fhe
Americas, 1994
The number of malaria cases reported in the Americas
increased steadily from 1974 to 1984. Since then close to 1
million cases have occurred annually, with 1,114,147 in 1994.
The largest number of cases were reported from Brazil, which
accounted for 50% of the total in 1994, followed by the
Andean Countries, which reported 29% of all cases. The
highest risk of transmission occurred in the Guyanas, where
the annual parasite index was 210/1000, 7 times higher than
in Brazil. The Guyanas also had the highest rate of falciparum
infection, with half of all infections due to
Plasmodium
falciparum,
compared with 1/3 in Brazil and 1/5 in the Andean
Countries. Migration into high risk areas and environmental
degradation continued to be major factors contributing to
sustained malaria transmission. Countries are gradually
adopting the global strategy for malaria control, but the
process is incomplete.
In 1994 the population of the Region of the Americas
was estimated at 763 million, of which 231 million (30.3%)
lived in areas where ecological conditions were propitiíous to
the transmission of malaria.
The exposure to the risk of contracting malaria in the
Americas yields a different and more accurate picture of the
distribution of the disease than one based solely on ecological
conditions propitious to transmission. Taking into account
that conditions for malaria transmission depend on factors
related to population movement, social stability, individual
adoption of attitudes and behavior that prevent and protect
against human/vector contact, and immediate access to
appropriate treatment, the countries of the Americas have
redefined their malarious areas on the basis of different levels
of risk of exposure to transmission (Figure 1).
Figure 1
Population living in malaria endemic areas* according
to transmission level, 1991-1994
200 200
100
100
1991 1 1991
Low 81,235 Mod.4. 1 66.504
Hih 72,391
1992 1maS 1094 50,801 118.,14 160.047
103,85 41.831 32,967 51,974 4e.225 37,409
* Population in thousands for all the Americas.
Table 1
Malaria morbidity in the Americas, 1970-1994
Population Morbidity per
(thousandsl Blood Mides 100.000 population
Year Country Malarlous Examinad Posiave Porcentage Total Matadous
Total Areas* Americas Areas
1970 505,819 181,257 9,925,162 344,170 3.47 68.04 189.88
1971 513,544 185,492 10,134,212 338,416 3.34 65.90 182.44
1972 524,774 190,448 9.695,953 284,813 2.94 54.27 149.55
1973 535,109 195,528 9,400,682 280,276 2.98 52.38 143.34
1974 544,865 200,755 8.997,318 269,003 2.99 49.37 134.00
1975 555,676 205,872 9,276,878 356,692 3.84 64.19 173.26
1976 565,249 211,086 9,352,775 379,364 4.06 67.11 179.72
1977 576,942 215,550 9,274.480 398,925 4.30 69.14 185.07
1978 587,704 220,153 9,493,751 468,923 4.94 79.79 213.00
1979 600,263 226,361 8,630,653 515,271 5.97 84.47 227.63
1980 610,021 231,366 8,943,369 602,836 6.74 98.82 260.56
1981 627,375 239,260 9,100,529 629,629 6.92 100.36 263.16
1982 635,954 245,307 8,826,418 715,177 8.10 112.46 291.54
1983 639,212 249,327 9,113,611 830,700 9.11 129.96 333.18
1984 659.535 257,276 9,422,827 931,356 9.88 141.21 362.01
1985 665,777 259,838 9,485,203 910,917 9.60 136.82 350.57
1986 662,983 263,371 10,070,388 950,570 9.44 143.38 360.92
1987 672,941 268,217 9,764,285 1,018,864 10.43 151.40 379.87
1988 703,370 280,758 10,092,472 1,120,040 11.10 159.24 398.93
1989 715,994 285,394 9,638,847 1,113,764 11.55 155.55 390.25
1990 698,741 278,600 9,459,912 1,045,808 11.06 149.67 375.38
1991 721,256 281,124 9,732,930 1,230,671 12.64 170.63 437.77
1992 725,564 289.948 9,373,323 1,187,316 12.67 163.64 409.49
1993 739,561 289,584 9,633,125 983,536 10.21 132.99 339.64
1994 763,305 231,323 8,261,090 1.114,147 13.49 145.96 481.64
Areas with ecological risk for malaria transmission. Information from some countries is incomplete.
10
Epidem¡olog¡cal Builetin
1
PAHO
risk of malaria in the Region, Table 1 shows an increase in
the malaria morbidity rates, on the basis of total population
of the Americas as well as the population inhabiting areas
that are ecologically propitious to transmission. Table 1 also
shows an increase in the diagnostic efficiency of the blood
samples taken, which is the result of a better concentration
of surveillance in the areas of highest risk. This is also
corroborated by the fact that a 2.7% increase in relation to
1993 in epidemiological surveillance of high-risk areas,
accompanied by a significant reduction in surveillance in the
areas of low and medium risk (27% and 16.2%, respectively)
in the same period.
In the countries of the Americas with active transmission
(Table 2), 35.6% of the population (146 million) is exposed
to the areas of greatest risk of transmission. In 1994 a 13.3%
increase in the number of cases diagnosed was reported in
relation to the previous year, partially due to a 14.6% increase
in P
falciparum
infections, the etiologic agent of malignant
tertian malaria, which indicates the high intensity of the
malaria transmission in these areas.
In recent years the epidemiological stratification of
malaria in the Americas has been accompanied by the
integration of case finding, diagnosis, and immediate
treatment activities by local health services. This can be
suspected cases, with diagnostic efficiency by the local health
services increased from 10.5% in 1993 to 16.2% in 1994. In
addition, active surveillance has declined by 22.7%, which
was anticipated due to the low diagnostic efficiency and high
operational cost of this activity. The 42.7% reduction in the
number of slides taken from febrile individuals by volunteer
collaborators could reflect the implementation of the "clinical
disease management" component of the new "Global Malaria
Control Strategy" adopted by the countries of the Region in
1992. Nevertheless, this greater availability of treatments by
the volunteer collaborators is not reflected in the overall
quantity of treatment provided which was maintained at the
same level as in 1993, probably indicating a change in the
distribution of resources within the different services in the
countries.
Table 3 details the geographic-political divisions as well
as the demographic location of exposure to high risk, its
causes, and the measures used for their control are presented.
From the characterization of the factors that determine the
persistence of the transmission, various control measures are
identified and stand out the need for intersectoral coordination
in order to ensure the sustainability of these measures over
time.
Table 2
Epidemiological situation of 21 countries with active malaria programs,
1994
Countries by Population of Blood Slides Parasites species
geographic malarious ---
---subregions areas*
Examined Positive falciparum vivax malariae and mixed
Mexico 45,248 1,923,575 12,864 63 12,801
Belize 210 49,179 9,957 400 9,557
Costa Rica 1,015 143,721 4,445 3 4,442
El Salvador 4,951 139,587 2,803 5 2,798
Guatemala 3,222 133,611 22,057 423 21,634
Honduras 2,319 315,893 52,110 568 52,110
Nicaragua 4,264 355,661 41,490 1,427 40,063
Panama 313 220,062 684 18 666
Sub-total 16,294 1,357,714 133,546 2,844 131,270 0
Haiti 5,628 54,973 23,140 23,140
Dominican Rep. 7,376 316,182 1,670 1,664 5 1
Sub-total 13,004 371,155 24,810 24,804 5 1
French Guyana 55 48,242 4,241 3,809 415 17
Guyana 132 168,127 39,566 22,503 16,985
Suriname 42 29,148 4,704 4,389 240 75
Sub-total 229 245,517 48,511 30,701 17,640 92
Brazil 20,600 2,671,953 564,406 197,009 367,251 146
Bolivia 3,009 128,580 34,749 4,806 29,916
Colombia 24,620 572,924 127,218 34,070 93,108 40
Ecuador 6,095 301,546 30,006 10,241 19,765
Peru 11,171 295,824 122,039 21,203 100,801 35
Venezuela 746 123,953 13,727 3,416 10,294 17
Sub-total 45,641 1,422,827 327,739 73,736 253,884 92
Argentina 5,366 14,070 948 1 947
Paraguay 1,270 96,885 583 12 571
Sub-total 6.,636 110,955 1,531 13 1,518 0
TOTAL 147,652 8,103,696 1,113,407 329,170 784,369 331
Population in thousands.
11
Table 3
Malarious areas at high risk of transmission, and control priorities, 1994
Population Reported cases
581,038
3, 184,903
2,.768,585 2,750,363
2.984,576
600,1 94
2,345,724 1,677,257 16,892.640 262 2.750 386 589 4.510 586 1.,795 188 11,066
Control measures applied Principal
in different areas vectors House. space and antilarval sprayings, A. albimanus
individual and massive radical cure treatments, A. vestitipennis entomological studies and environmental A. pseudopunct managemant promotion.
Causes producing the
persistance of transmission
mportant migratory movements of agricultural workers
arriving from the south.
Precarious housing,
Vector resistance in some dispersed areas of limited extension.
Popilation habit of staying outdoors tor several hours of the
afternoon and evening.
Sprayings and treatments with drugs.
302 Radical treatment, focal and space spraying. A. albimanus 849
445 984 2,580
2.254 Spraying, drug treatments, larvicides, small A. albimanus engeneering works, debnet use.
Non-coordinated indoor spraying and low coverage of diagnosis and treatment of the
population.
Integrated measures implemented; drug treatment; diffsrent spraying methods tor physical and larval control: and community paticipation.
Prophylatic treatments for inmigrants drug treatment barrier, peridomicile fogging indoor
spraying, cleaning of channels, fish rearing.
breeding site treatment with Rti.
A. darlingi
Diagnosis.
Radical treatment.
A. albimanus Population movements.
De-reforestation
Intense rainfall
Border areas with intense population movements. Agricultural development with unstable manpower and intense
de-forestaton.
Large flow of susceptibles, inopponune control measures and lack of inter-agency coordination.
Low social panticipation. Defficient decentraliiation process.
Precraious housing, unhealthy environment, migration, low
education, povety, ideal vector habitat and types of
cultivation.
A. albimanus Unstable politics and migration. Insecticide resistance.
A. albimanus Presence of rice crops.
A. darl¡ngi Increase of at r¡sk population due to creation of industrial
parks and rice cultivation. Migrant populations.
Presence of large lagoons that are used for cattle watering.
Dscentralization process in development. A. albimanus Low coverage of the SILAIS.
A. pseudopunct. High unemployment level.
High human mobility. Urban epidemic.
Nomadic migration of ethnic groups to the south.
Increase of population movements tu the north.
Border migration. A. albimanus Commercial exchange.
Rice growing.
Extensive use of migrant manpower
for agriculture and construction.
Forestry and mining areas of Amerindian groups.
Migratory movements for exploitation of gold, forests and
natural reserves.
12
Epidemiological BuIletin
1
PAHO
Countries Mexico: Campeche Chiapas Guerrero Michoacan Oaxaca Quintana Roo
Sinaloa Tabasco Sub-total 1.245 1.179 680 3,533 1.210 2,110 9.957 Belize: Corozal Orange Walk
Belice Cayo Stann Creek Toledo Sub-total-Costa Rica:
Canton Los Chiles Canton Limon Canton Talamanca
Canton Matina Sub-total
El Salvador
Costa Pacifico
area hiperendem,.
Guatemala: El Peten Huehuetenango Quiche Alta Verapaz Escuintia Sub-total Honduras:
Region Sanitaria I
Region Sanitaria II
Region Sanitaria III Region Sanitaria VI Region Sanitaria VII
Sub-total
Nicaragua:
Rio San Juan Chinandega
Leon
Jinotega Matagalpa Nueva Segovia
R.A.A.N. R.A.A.S.
Managua
Sub-total
Panama:
8ocas del Toro Changuinola Chiriqui Grande Chpirgana
Sub-total
Haiti:
Dominican Republic:
Comendador Banica El Llano Pedernales Dejabon Panrtido Sub-total French Guayana Guayana
Region I
Region VII Region Vii
Region IX Sub-total 34,993 33.207 62.000 40,800 20,000 19.000 210,000 15,561 69.728 15.956 19.825 121,070 1,233,133 310.838 214.450 262.108 391.300 440.932 1,619,628 247.677 285.033 319.209 99,272 228,081 1.179.272 37,508 357.612 373,250 190,067 403.917 139,888 115,295 72,075 1,193,930 2,883,542 21,888 64.684 14,433 29,488 130,493 25.118 11.632 9.986 19,471 24,407 5,570 96,184 '53,497 5,086 1,747 2,476 5,630 1,273 16.212 6.804 5,484 6.908 6.,739 8.373 34.308 1.547 7,539 3,916 3,391 4,703 2,456 2,404 735 11,039 37.730 189 258 96 83 626 32 14 2 3 99 4 154 11,415 4,419 8,692 3,506 28.032
__
Table 3
Malarious areas at high risk of transmission, and control priorities, 1994
Countdres Population Reported Control measures applied Principal Causes producing
Cases in diffeent areas Vectors the persistence of transmission
25.813 6.539 45.043 8,642 93,550 147,640 127 121 24,467 478,815 26,880 19,845 4,260 14,211 13,605 7,377 7,685 4,975 2,026 100,864
Integrated control of low coverage due to difficult A. darlingi access and low stability of the descentralization
process.
Lack of coordination between financial and
administrative policies.
Diagnosis and treatment through the general health A. pseudopunct.
services. A. benarrochi
Residual spraying, spatial spraying environmental
health.
,379 Spraying and fogging, application of larvicides. 820
321 52 ,246
3,818
752 Epidemiologic surveillance and spraying.
308 Detection and treatment of cases., hous spraying. 125
433
3,106 Case detection and supervised treatments. chemical control and physical control of breeding sites ith
petroleum.
1,459 Health education in prevention and control.
A. daringi A. aquasalis
A. nunenovari
All the epidemiologic factors that determine malaria transmission in 'ecological areas of the agncultural frontier', mining areas and internal migration.
Delays in th eimplementation of the global malaria control strategy.
Implementation process started in 1994.
Mining areas without control. in the rainforest. Migrant movements in the border areas.
A. pseudopunct. Intense internal and external migration. Accessibility limited by climatic factors.
Economical and financial factors limit activities.
A. darlingi
A. darlingi A. pseudopunct.
Increase of the number of breeding sites.
Migrations. Indigenous groups.
Temporary workers.
Lack of complete and clear political decision. A priority level was only assigned from August onwards.
Permanent migration with border communities of Brazil and to the south with Argentina. Resistance to change and implementation of new strategies among some malaria officers. Lack of complete economic support.
645
5,210
51,183 Indoor spraying, physical control. 34,660 lmpregnated bednets, topical repellents. 15,880
10,730
8,017
120.470
9,702 Indoor house spraying.
728 1,842 1,382 708 293 360 467 219 233 15.934 A. albimanus
A. nuneztovari
A. darlingi A. puntimacula
A. evansae
A. albimanus
Socio-political factors.
Mining. Drug treatments. Migration. Colonization.
Illicit crops.
Vector behavior.
Low operating coverage by the national program.
Lack of political willingness to salve labor conflicts
within the old centralized structure.
... Information is not available
Epidemiological
BuIletin
¡ PAHO
13~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
401,961 94.200 479,073 271,629 439,995 1.271,090 695,757 259.763 3,859.468 727,932 428.682 142,264 588.135 390,561 129,271 211,944 45,762 66,884 2.731.435 58,000 82.182 2,200 23,112 16,694 182.168 1 1 3 Brazil Acre Amapa Amazonas Maranhao Mato Grosso
Para Rondonia Roraima Sub-total Peru: Piura Sullana Tumbes Loreto Jaen Lambayeque San Martin Ucayali
Madre de Dios
Sub-total Venezuela: Ama2onas Bol¡var Delta Amacuro Tachira Apure Sub-total Argenotna:
Fase de ataque Sector I-Tartagal Sector Il-Oran
Paraguay:
Caaguazu Alto Parana
Sub-total
Bolivia:
Depanrt.: BENI Provincias Vaca Diez
Depart.: PANDO Provincias Fco. Roman Manuripi Abuna
Nicolas Suárez
Depart.: TARIJA Provincias
Gran Chaco
O'Connor Depan.: chuquisaca Provincias
1,4,5,10 Oropeza
Tomina H. Siles
Luis Calvo
Sub-total
Colombia:
1. Bajo Cauca 2. Orinoquia 3. Pacifico 4. Urebl
5. Amazonia
Table 4
National funds assigned to the health sector, public health and malaria programs, 1994
(Amounts US dollars)
Countries by Health Public Health Percentage Malaria Porcentage Malaria Program
geographic Sector Budget Budget assigned Program for Health Loans or Grants
subregions (total) to Public Budget Sector
Health
13,292,300,000 33,667,667
1.,095,1 53,300
343,350,300
7,698,858 360,554
9,411,764,706
1,038,105,568 126,458,939
4,950,294,950
1,51 5,457,000 2,648,610 185,320 100,789,020
70,646,659
171.657,150
1,477,531 50,245
11.40 7.87
9.20
49.99
13.94
8,705,882,353 92.50
103,070 637,814,868
3,026,720,994
61.44
61.14
230,565,206 91,179,875 39.55
30.529.720.049 14.324,612.695 46.92
... Information not available.
With regard to the measures used to protect against
transmission, the vector control activities continue to be
applied by
the countries, with an increase in relation to
1993
in the quantity of insecticides used; on the order of
40% for
DDT and 100%
for Fenitrothion in
1994.
The control programs, however, are undergoing a drastic
reduction in budgetary funding and therefore are obtaining
more of their financing each year through loans and grants
from outside
the health sector.
Table 4 reflects a 41%
reduction in the regular budget as compared to
1993, and a
75% increase
in loans and grants. Moreover, an important
increase is seen in investment in research on
malaria in
endemic countries
of the Region. In
Brazil, Colombia,
Mexico, and Venezuela US$ 6.5 million
were invested for
research in 1994--a 58%
increase over
the previous year.
Source:
This article is a summary from the original document"Regional Status
of
Malaria Program in the Americas". It has been prepared by the Division of
Disease Prevention and Control, Program of Communicable Diseases, HCP/
HCT, PAHO.
14
Epidemiological BuIletin
1
PAHO
Mexico Belize Costa Rica El Salvador Guatemala Honduras Nicaragua Panama
Haiti Dominican Rep.
French Guyana Guyana Suriname
Brazil
Bolivia Colombia Ecuador Peru Venezuela
Argentina Paraguay
TOTAL
0.23 1.83
0.12
1.06
79,407 393,308 682,571 288,703 576,382 386,004 124,224 30,297,000
617,462 138,000 1,314,286
1,611,927
3,633,545
50,000 667,171
295,483 5,494
12,117,647
619,430 14,614,045 5,253,888 3,062,696 24,233,445
3,000,000 1,030,831
102,562.351
3.84 1.52
0.13
4.15
0.49
24,400,000
20,000
25,319,792
0.45
0.336 52,270,391
