Neotrop. Helminthol., 1(2), 2007

Cystic echinococcosis is a zoonosis caused by a

cestode, Echinococcus granulosus, of the Taeniidae

family. The adult form of the tapeworm affects

canids, particularly dogs and foxes, while the

larva is harbored by sheep, cattle, goats and other

mammals.

The disease is an important public health problem

with significant economic impact in the southern part

of South America, i.e., Argentina, Chile, Uruguay,

Brazil (Rio Grande do Sul), Peru and Bolivia. It is

mainly associated with sheep production systems

(Larrieu et al., 2004; Craig & Larrieu, 2006).

Peru appears to have the highest infection rates

in Latin America today, reporting up to 11 cases

per 100,000 inhabitants. However, some endemic

regions like Pasco, Junin or Huancavelica, may

detect up to 34 cases per 100,000 inhabitants (Pérez,

2007).

Among the multiple issues that affect the parasite’s

transmission and help perpetuate its endemicity,

there are biological, demographic, environmental

and cultural risk factors, which are worsened by

husbandry systems that are highly favorable for the

disease.

Echinococcosis bears an important impact on

public health, mainly because it has a chronic

course progression that may lead to various degrees

of handicap, and even death. Moreover, it has a

negative impact on economy, since it causes losses

because of the offal seized, it reduces the production

of beef, milk and wool, and impairs livestock

fecundity (Togerson, 2001).

The populations primarily affected are rural

workers and their families, people that live in small

villages or impoverished town belts, migrants from

rural areas that often settle in extremely poor

neighborhoods, with high rates of unmet basic

needs and severe social fragility. These groups

usually keep the habit of feeding their dogs with

offal from home-slaughtered animals, perpetuating

the parasite’s biological cycle. The lack of drinking

water and utilities, together with a low educational

level and poor sanitary conditions increase the risk

of transmission of these diseases.

Since the mid twentieth century, the Southern Cone

countries have implemented a range of intervention

programs to address this issue. Many of them persist

to date and are operating regularly; others have

been applied intermittently, while others have been

totally discontinued. Examples of the latter were

the pilot programs developed in Peru between 1975

– 1984 at the SAIS Tupac Amaru and Pachacutec

Ltda (Ministerio de Salud, 1989).

The current status of the Latin American control

programs, after 30 years of operation, indicates

that those designs do not yield the results expected,

clearly suggesting they warrant reengineering

(Guarnera, 2006). New designs should contemplate

complementary action lines, adapting strategies to

local situations and considering approaches tailored

to specific populations.

Uruguay’s control program is a clear example;

after analyzing the results obtained with the earlier

programs, we are skeptical about the efficacy of

targeted dog dosing with praziquantel in rural areas

1 Comisión Nacional Honoraria de Zoonosis, Ministerio de Salud Pública, República Oriental del Uruguay.

EDITORIAL

CYSTIC ECHINOCOCCOSIS AS A PUBLIC HEALTH PROBLEM IN LATIN

AMERICA AND NEW APPROACHES TO ITS CONTROL

Ciro Ferreira1; Pilar Irabedra1

Sugestion citation: Ferreira, C & Irabedra, P. 2007. Cystic echinococcosis as a public health problem in Latin America

and new approaches to its control. Neotropical Helminthology, vol. 1, no 2, pp. 55-57.

Neotrop. Helminthol., 1(2) , 2007

EQUINOCOCOSIS QUÍSTICA COMO UN PROBLEMA DE SALUD PÚBLICA EN

AMÉRICA LATINA Y NUEVOS ENFOQUES PARA SU CONTROL

Cystic echinococcosis public health problem in Latin America Ferreira, C & Irabedra, P.

as the only tool to tackle the problem. In countries

like Uruguay, implementation of that strategy leaves

out broad sectors for various reasons.

We cite just two reasons to illustrate that : economic

and geographical. When dog owners have to

pay for the deparasitation service, the people or

communities that cannot afford it will obviously

not comply. The other cause of failure is the poor

accessibility in vast areas of the American continent

due to geographical hurdles.

Furthermore, in spite of the unquestionable value

of mathematical models (Roberts et al., 1986), their

application in real life has often failed to provide the

results expected , particularly in a complex health/

disease process involves many biological, ecological,

social and economic factors.

The control program currently implemented in

Uruguay is based on a “risk-focused approach”.

Surveys conducted in the framework of such

programs in small villages and extremely poor

urban areas, where no targeted praziquantel had

been administered, or where anti-helmintic dosing

had been sporadic or irregular, coproantigen tests

were positive for E. granulosus in 4 % of the dogs,

and as high as 7 % in the case of dogs labeled as

“offal eaters”. Those groups represent true sources

of infection (nodes) (Comisión Nacional Honoraria

de Zoonosis, unpublished data).

These values are consistent with those found in rural

areas where targeted anti-helmintic dosing of dogs

is conducted.

The new strategy tries to address those issues by

reinforcing several lines of action simultaneously

and synergistically:

Epidemiological re-definition, reviewing,

redesigning and increasing coverage of

administration of praziquantel to dogs,

adapting to each area’s epidemiological status,

especially targeting the sources of infection as

a priority.

Detection of individuals with asymptomatic

liver hydatic cysts through ultrasound screening

(Perdomo et al., 1990). The use of serology

initially in countries with high infection rates is

not to be excluded; that issue should be decided

based on the specific countrys characteristics,

•

applying a comprehensive vision of health .

Development and/or promotion of programs

for the responsible possession of dogs; one of the

key components must be controlling the size of

dog populations through surgical sterilization;

there is evidence showing that the technique

is time sustainable and widely accepted by the

population.

Emphasizing the educational component,

prioritizing the direct interventions on the

field, while promoting the tasks required for an

early detection of hydatic cysts. However, the

relevance of other strategies, such as curricular

education should not be disregarded.

Commitment of stakeholders at all stages of

implementation of the program.

Finally, cooperation among the countries in the

region should be seen as a key instrument to improve

institutional capacities in the pursuit of common

development goals.

In Resolution 7, the XII Inter-American Ministerial

Meeting on Health and Agriculture (RIMSA XII)

held in 2001 highlights cystic echinococcosis as

a significant Public Health problem, urging the

countries to formulate plans of action and strategies

aimed at eliminating the disease in the Southern

Cone, the Andean Area and other sub-regions of

the Americas.

In this context 2007 Peru and Uruguay launched

a Technical Cooperation Project for the Prevention

and Control of Cystic Echinococcosis in Peru. The

project was developed in the framework of the

strategy and vision of support to the initiatives for

the control of this zoonosis in the South American

countries, as declared by the country members of

the Southern Cone Sub Regional Project for the

Control and Surveillance of Hydatidosis, with

the technical cooperation of the Pan American

Health Organization/ World Health Organization

(PAHO/WHO).

This cooperation project opens a very important

pathway for the exchange of experiences and

technology “made in” Latin America; it intends to

be comprehensive, more efficient and effective

than past programs, and inexpensive, allowing

for the two countries’ simultaneous and synergic

development. An example of such cooperation is

the exchange agreed in relation with the diagnosis

•

Neotrop. Helminthol., 1(2), 2007

of dog echinococcosis between Uruguayan and

Peruvian institutions.

Achieving sustainability of the programs in the region

is paramount. In that respect, mutual cooperation

plays a potential key role, contributing with a

deep, interdisciplinary approach, encompassing

the social and economic issues that have a strong

impact on the epidemiology of diseases, all within a

comprehensive context of zoonosis control.

There is no doubt that these instances are of outmost

importance for improving communities’ health,

preventing diseases and improving their quality

of life, typically that of the individuals in greatest

social and economic need. Equally important, this

initiative should also be regarded as a very valuable

chance to establish links between countries that

share common problems and objectives.

Craig, PS & Larrieu, E. 2006. Control of cystic

echinococcosis/hydatidosis: 1863-2002. Advances

in Parasitology, vol. 61, pp. 443-508.

Guarnera, E. 2006. Situación actual de los

programas de control de equinococosis

quística en América del Sur. 3ª. Reunión del

Proyecto Subregional Cono Sur de Control

y Vigilancia de la Hidatidosis. Porto Alegre,

RS, Brasil.

Larrieu, E, Arambulo, IIIP & Tamayo, H. 2004.

Equinococosis quística: epidemiología y control en

América del Sur. Parasitología Latinoamericana,

vol, 59, pp. 82-89.

Ministerio de Salud 1989. Epidemiología de la hidatidosis

en el Perú. En: Anales del Seminario Nacional

de Zoonosis y Enfermedades de Transmisión

Alimentaria. 1989. Lima. p. 122-137

Pérez, LCR. 2007. Proyecto de control de hidatidosis en el

Perú por vigilancia epidemiológica. Tesis para optar

el grado de Doctor en Medicina, Facultad de

Medicina, Universidad Nacional Mayor de

San Marcos, Lima.

Perdomo, R, Parada, RJr, Alvarez, C, Cattivelli,

D, Geninazzi, H, Barragué, A.D, Ferreira,

C, Rivero, E, Monti, J & Parada, J. Estudio

epidemiológico de hidatidosis. Detección precoz por

ultrasonido en áreas de alto riesgo. Revista Médica

del Uruguay. 1990; 6:34-47.

Roberts, MG, Lawson, JR & Gemmell, MA.

1986. Population dynamics of echinococcosis and

cysticercosis: mathematical model of the life cycle of

Echinococcus granulosus. Parasitology, vol.

92, pp. 621-641.

Togerson, PR. 2001. Economical aspects of echinococcosis.

Archivos Internacionales de la Hidatidosis,

vol. 34, p. 7.

REFERENCES

Correspondence to author: Pilar Irabedra

Complete address: Bulevar España 2673.

Montevideo. Uruguay.

E-mail: irabepi@adinet.com.uy

Phone: 7099258 - 7070331

Cystic echinococcosis public health problem in Latin America Ferreira, C & Irabedra, P.

Neotrop. Helminthol., 1(2) , 2007