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National prevalence of larval echinococcosis in sheep in slaughtering plants Ovis aries as an indicator in control programmes in Uruguay
Acta Tropica 85 (2003) 281 /285 www.parasitology-online.com
National prevalence of larval echinococcosis in sheep in slaughtering plants Ovis aries as an indicator in control programmes in Uruguay P.A. Cabrera a,*, P. Irabedra b, D. Orlando b, L. Rista b, G. Hara´n b, G. Vin˜als b, M.T. Blanco b, M. Alvarez b, S. Elola b, D. Morosoli b, A. Moran˜a c, M. Bondad b, Y. Sambra´n b, T. Heinzen d, L. Chans d, L. Pin˜eyro d, D. Pe´rez d, I. Pereyra d a
Facultad de Veterinaria, Departamento de Parasitologı´a, Montevideo, A. Lasplaces 1550, Uruguay b Comisio´n Nacional de Hidatidosis, MSP, Montevideo, Bulevar. Espan˜a 2673, Uruguay c Facultad de Veterinaria, Departamento de Patologı´a, Montevideo, Uruguay d Direccio´n de Industria Animal, MGAP, Uruguay
Abstract Diagnostic surveys carried out on ovine larval echinococcosis in slaughtering plants at a national level in 1998 made it possible to meet several objectives, i.e. to estimate the existing levels of prevalence, to evaluate the effectiveness of the control actions applied by the Programme against Hydatidosis and to contribute to the improvement of the health information systems for epidemiological surveillance. The work included sheep (Ovis aries ), both lambs (2 /4 teeth) and adults (6 /8 teeth). A random sample was performed among sheep from the plants that slaughter the majority of animals in the country. The sample included 22 animals per herd, and it involved removing their offal (liver, lungs and heart) and processing serial sections at the laboratory. The histopathological studies were performed on the lesions that could not be adequately identified at gross examination, and those that were so small that had to be submitted for confirmation of the diagnosis. Of the 2035 animals that were examined, 1019 were lambs (2 /4 teeth) and 1016 were adults (6 /8 teeth). The prevalence of larval echinococcosis was 7.7% in lambs and 18.0% in adults. The overall prevalence in the liver was 8.5 and 8.0% in the lungs. As to the characteristics of the morphologic structures of the larvae, in younger animals 29% of the lesions were calcified, and 71.0% were hyaline, while in older animals the proportions were 34.4% calcified versus 65.6% hyaline. Other conditions found in the liver parenchyma included: white stain (0.8%), caseous lymphadenitis (3.0%), abscess (0.4%), larvae of Taenia hydatigena (5.1%), Fasciola hepatica (3.9%). And 1.7% of the animals presented larvae of Taenia ovis in the cardiac muscle. Previous surveys carried out in 1994 using the same methodology showed a prevalence of 15.2% in 2 /4 teethed animals and 33.9% in 6 /8 teethed animals, thus confirming that rates have decreased by 49.6 and 47.0%, respectively. The data obtained reflect the reduction of areas contaminated with eggs of Echinococcus granulosus , which would cause a loss in immunity against this parasite after a certain time. Prevalence of larvae T. hydatigena and T. ovis could change if more sites were
* Corresponding author E-mail address: [email protected] (P.A. Cabrera). 0001-706X/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved. PII: S 0 0 0 1 - 7 0 6 X ( 0 2 ) 0 0 2 1 4 - 0
282
P.A. Cabrera et al. / Acta Tropica 85 (2003) 281 /285
considered, a fact that was confirmed in studies carried out in our country. The species O. aries must be used as an indicator in the control programmes, especially in the category of 2 /4 teethed lambs. The fact they are not as frequent in our market must be considered; in 1998 they accounted for only 3.0% of the total numbers of animals. # 2002 Elsevier Science B.V. All rights reserved. Keywords: Prevalence; Echinococcus granulosus ; Sheep; Uruguay
1. Introduction Echinococcus granulosus is endemic in Uruguay. Its biologic cycle causes a cyclo-zoonotic infection impacting on public health and animal production, with ensuing consequences on the meat industry. As occurs with other helminths, E. granulosus has a negative binomial distribution in its definitive and intermediate hosts, and only a very small number of animals host large burdens of parasites (Gemmell and Lawson, 1986; Ming et al., 1992; Roberts et al., 1987). Consistent with those factors, studies aimed at establishing infection rates and intensity should be performed in sheep, since these are the most sensitive markers of the degree of environmental contamination caused by the eggs of the agents producing the hydatid disease (Cabrera et al., 1995). The economy based on cattle raising reports important losses due to the seizure of offal with parasites, an activity carried out by the Veterinary Inspection Service (Ministry of Agriculture), which generates the data that feed an information system providing feedback to the health control campaigns developed by the official agencies (Sadykhov and Melikor, 1965; Inderkum et al., 1987; Bonifacino et al., 1995; Orlando et al., 1999). Slaughtering operations are regulated by the number of animals in the slaughtering lot, circulation, rate, morphologic features of the specimens, location sites of the parasites within the organs, developmental status of the metacestodes and other parasitic forms, as well as other confounding conditions. Therefore, diagnostic tasks were coordinated in the slaughter plants and the laboratory in 1994, in order to determine the national prevalence of larval echinococcosis in sheep of all categories, resulting in decidual teeth animals, 2.3%; 2 /4 teethed animals: 15.2%; and 6 /8 teethed
animals: 33.9%, with an overall figure for sheep of 16.2% (Cabrera et al., 1989, 1991, 1996). The second study assessing the prevalence of echinococcal larvae in sheep in the slaughtering plants was performed in 1998 and it was designed to estimate the existing prevalence levels in each age group. These data enable us to evaluate the effectiveness of the control actions applied by the National Plan against Hydatidosis (Orlando et al., 1995) and contribute to the improvement of the health information systems for epidemiological surveillance.
2. Materials and method The work included sheep (Ovis aries ), using a random sample for the category including lambs (2 /4 teeth) with E /2% and Z /95%, and adults (6 /8 teeth) with E /3% and Z /95%, drawing sheep from the plants major slaughterhouses in the country. Of the 2035 animals studied, 1019 were lambs and 1016 were adults. Offal of the first 22 animals in each herd were examined, by origin and category; special care was taken to avoid repeating the slaughter plants of origin. After removing and labeling the specimens, they were processed at the laboratory by making a series of 3/5 mm, wide sections of the liver, lungs, spleen, kidneys and heart. The main data collected included number of cysts per animal, anatomic site, viability and fertility (Lloyd et al., 1991). To differentiate hydatid cysts from cysticerci of Taenia hydatigena or T. ovis and from Corynebacterium pseudotuberculosis abscesses, histopathologic studies were performed in those lesions in which the gross examination was questionable, and in those requiring confirmation because of their small size.
P.A. Cabrera et al. / Acta Tropica 85 (2003) 281 /285
The fertility of the E. granulosus cysts were determined to be fertile by demonstration of protoscolices, and the viability of the latter was assessed with the eosin exclusion test. The heart was sectioned and examined to rule out parasites, particularly T. ovis .
3. Results The prevalence of hydatid larvae in 2/4 teeth sheep was 7.7% and in those with 6/8 teeth it was 18.0%. The prevalence with liver location was 8.50%, and in the lungs it was 8% for all the animals (Tables 1 and 2). In younger animals, 29% of the larval cysts (hydatids) were calcified and 71% were hyaline. By comparison, in adult animals, 34.4% were calcified and 65.6 were hyaline (Table 3). Other parasitic conditions found in the hepatic parenchyma were larvae of T. hydatigena (5.06%), white stain (0.8%), caseous lymphadenitis (3.04%), abscesses (0.4%), lesions caused by Fasciola hepatica (4.0%) and larvae of T. ovis in the cardiac muscle (1.8%; Table 4).
4. Discussion Previous surveys carried out using the same methodology in 1994 documented prevalence of 15.2% for the 2/4 teethed animals and 33.9% in 6/ 8 teethed animals, which indicates a decrease of 49.6 and 47.0%, respectively.
283
The data obtained indicate reduction in the areas contaminated with eggs of E. granulosus , which in time will lead to a loss of immunity against the parasite. The intensity of the infection in individual animals was seen to increase with age, which implies that the number of eggs swallowed and the frequency of their ingestion are too low to maintain an effective immunity. The prevalence data collected on larval T. hydatigena and T. ovis infections could vary if more animals in more locations were considered, something that was confirmed in studies carried out in Uruguay. The larvae of T. hydatigena (Cisticercus tenuicollis ) and T. ovis (C. ovis ) show a number that indicates that the sheep have acquired immunity for re-infection. Visceral caseous lymphadenitis is common in our country, and it should be taken into account since it can distort the prevalence curves of E. granulosus , and differential diagnoses must be established by slice and culture of the lesions.
5. Conclusion The data obtained document a significant decrease in E. granulosus infection in livestock since the 1994 /1998 period, when intense actions were implemented to eliminate tapeworm parasites from dogs with praziquantel a nation-wide programme, reducing the areas contaminated with eggs. This was expected to lead to the loss of immunity of intermediate hosts to the parasite after a certain time. The data regarding larval T.
Table 1 Number and percentage of animals presenting E. granulosus by age categories and site of the larvae Categories (number of teeth)
Total
Number of animals with parasites Total number
Sites
Total
Livers
N
%
N
Lungs %
N
%
Total
2035
261
12.8
173
8.5
163
8.0
Lambs (2 /4) Adults (6 /8)
1019 1016
78 183
7.65 18.01
53 120
5.2 11.81
44 119
4.31 11.71
P.A. Cabrera et al. / Acta Tropica 85 (2003) 281 /285
284
Table 2 Larval echinococcosis per category and organ Category (teeth)
Liver
Lung
Liver/lung
Total Positive
% Negative
Total
2 /4 6 /8
34 64
25 63
19 56
78 183
941 833
1019 1016
7.65 18.01
Total
98
88
75
261
1774
2035
12.81
Table 3 Morphologic characteristics of the hydatic larvae Lambs (2 /4 teeth)
Hyaline Calcified
Adults (6 /8 teeth)
Liver
Lung
Total
%
Liver
Lung
Total
%
32 19
39 10
71 29
71 29
49 44
75 21
124 65
65.6 34.4
References
Table 4 Infections and various conditions found in the viscera
Larval T. hydatigena Larval T. ovis F. hepatica Caseous lymphadenitis Abscesses White stain
2 /4
6 /8
Total
%
42 17 24 23 3 11
60 16 56 39 5 5
102 33 80 62 8 16
5.01 1.62 3.93 3.04 0.39 0.78
hydatigena and T. ovis could increase in prevalence if more frequent anatomic sites like head, neck and limb muscles were examined. The number and prevalence of other conditions that could be mistaken for larval cestodes require the use of this type of methodology that includes laboratory diagnosis, although it is not applicable at an industrial level. Infection in sheep (O. aries ) should be used as an indicator of progress in control programmes, especially in animals in the 2/4 teeth category. In practice, however, sheep of this age are not frequent in our market, accounting for only 3.0% of the national slaughter in 1998. Thus, obtaining a high number in animals at that age for the study may be difficult.
Bonifacino, R., Giacoia, A., Murillo, N., Orlando, D., Perdomo, R., 1995. Situacio´n de la hidatidosis en el Uruguay. Memorias de la reunio´n del Grupo cientı´fico sobre avances en la prevencio´n, control y tratamiento de la Hidatidosis, Montevideo, Uruguay, Octubre 26 /28, 1995. Pan American Health Organization, pp. 242 /276. Cabrera, P.A., Parietti, S., Lo´pez, J., Sampaio, I., 1989. Hidatidosis intraparenquimatosa con procesos fe´rtiles en categorı´as jo´venes de ovinos y suinos. Taller Internacional de Investigacio´n Ba´sica en Helmintos. 2 do. Taller Regional de Investigacio´n Ba´sica en Hidatidosis, Solı´s, Uruguay, p. 142. Cabrera, P.A., Parada, L., Barcelona, C., Burgues, C., Acun˜a, A., Paolillo, E., Agulla, J., Camejo, G., Ramos, M., 1991. Hidatidosis en el a´rea rural: estudio simulta´neo en tres hospederos. Capı´tulo ovinos. X Congreso Latinoamericano de Parasitologı´a, Montevideo, Uruguay, p. 362. Cabrera, P.A., Hara´n, G., Benavides, U., Valledor, S., Perera, G., Lloyd, S., Gemmell, M.A., Baraibar, M., Moran˜a, A., Maissonave, J., Carballo, M., 1995. Transmission dynamics of Echinococcus granulosus , Taenia hydatigena and Taenia ovis in sheep in Uruguay. Int. J. Parasitol. 35 (7), 807 /813. Cabrera, P.A., Irabedra, P., Trindade, J., Agulla, J., Heinzen, T., Alvarez, M., Elola, S., Sambra´n, Y., Moran˜a, A., Orlando, D., Lazaneo, H., 1996. Determinacio´n de la prevalencia de la hidatidosis ovina nacional en playas de faena, Uruguay. Hidatidosis 2, 18 /28. Gemmell, M.A., Lawson, J.R., 1986. Epidemiology and control of hydatid disease. In: Thompson, R.C. (Ed.), The Biology
P.A. Cabrera et al. / Acta Tropica 85 (2003) 281 /285 of Echinococcus and Hydatid Disease. George & Unwin, London, pp. 189 /216. Inderkum, R., Perdomo, E., Serna, M., Paullier, C., 1987. Estudio de la patologı´a hepa´tica en establecimientos de faena. Patologı´a hepa´tica ovina: corderos y borregos. IV Congreso Nacional de Veterinaria. SMVU, Montevideo, Uruguay. Lloyd, S., Martin, SC., Walters, T.M.H., Soulsby, E.J.L., 1991. Use of sentinel lambs for early monitoring of the South Powys Hydatidosis Control Scheme: prevalence of Echinococcus granulosus and some other helminths. Vet. Rec. 129, 73 /76. Ming, R., Tolley, H.D., Andersen, F.L., Chai, J., Sultan, Y., 1992. Frecuency distribution of Echinococcus granulosus in sheep populations in the Xinjiang Uygur Autonomous Region, China. Vet. Parasitol. 43, 233 /241.
285
Orlando, D., Cabrera, P.A., Irabedra, P., Trindade, J., 1995. Controlled dosification plan at a national level national programme against hydatidosis. In: Proceedings of the XVII International Congress of Hydatidology. Arch. Int. Hidatid., Limassol, Chipre, p. 299. Orlando, D., Irabedra, P., Cabrera, P.A., 1999. Epidemiologı´a de Hidatidosis en las Americas. Boletin Asociacio´n Internacional de Hidatidologı´a, pp. 5 /15. Roberts, M.G., Lawson, J.R., Gemmell, M.A., 1987. Population dynamics in echinococcosis and cysticercosis: mathematical model of the life cycle of Taenia hydatigena and T. ovis . Parasitology 94, 181 /197. Sadykhov, I.A., Melikor, I.F., 1965. On the finding of the economic loss from echinococcosis in livestock production in Azerbaidzhan. Trudy Inst. Zool. Akad. Nauk Azerbaidzhan. SSR. Voprosy Parasitologii 24, 17.
National prevalence of larval echinococcosis in sheep in slaughtering plants Ovis aries as an indicator in control programmes in Uruguay P.A. Cabrera a,*, P. Irabedra b, D. Orlando b, L. Rista b, G. Hara´n b, G. Vin˜als b, M.T. Blanco b, M. Alvarez b, S. Elola b, D. Morosoli b, A. Moran˜a c, M. Bondad b, Y. Sambra´n b, T. Heinzen d, L. Chans d, L. Pin˜eyro d, D. Pe´rez d, I. Pereyra d a
Facultad de Veterinaria, Departamento de Parasitologı´a, Montevideo, A. Lasplaces 1550, Uruguay b Comisio´n Nacional de Hidatidosis, MSP, Montevideo, Bulevar. Espan˜a 2673, Uruguay c Facultad de Veterinaria, Departamento de Patologı´a, Montevideo, Uruguay d Direccio´n de Industria Animal, MGAP, Uruguay
Abstract Diagnostic surveys carried out on ovine larval echinococcosis in slaughtering plants at a national level in 1998 made it possible to meet several objectives, i.e. to estimate the existing levels of prevalence, to evaluate the effectiveness of the control actions applied by the Programme against Hydatidosis and to contribute to the improvement of the health information systems for epidemiological surveillance. The work included sheep (Ovis aries ), both lambs (2 /4 teeth) and adults (6 /8 teeth). A random sample was performed among sheep from the plants that slaughter the majority of animals in the country. The sample included 22 animals per herd, and it involved removing their offal (liver, lungs and heart) and processing serial sections at the laboratory. The histopathological studies were performed on the lesions that could not be adequately identified at gross examination, and those that were so small that had to be submitted for confirmation of the diagnosis. Of the 2035 animals that were examined, 1019 were lambs (2 /4 teeth) and 1016 were adults (6 /8 teeth). The prevalence of larval echinococcosis was 7.7% in lambs and 18.0% in adults. The overall prevalence in the liver was 8.5 and 8.0% in the lungs. As to the characteristics of the morphologic structures of the larvae, in younger animals 29% of the lesions were calcified, and 71.0% were hyaline, while in older animals the proportions were 34.4% calcified versus 65.6% hyaline. Other conditions found in the liver parenchyma included: white stain (0.8%), caseous lymphadenitis (3.0%), abscess (0.4%), larvae of Taenia hydatigena (5.1%), Fasciola hepatica (3.9%). And 1.7% of the animals presented larvae of Taenia ovis in the cardiac muscle. Previous surveys carried out in 1994 using the same methodology showed a prevalence of 15.2% in 2 /4 teethed animals and 33.9% in 6 /8 teethed animals, thus confirming that rates have decreased by 49.6 and 47.0%, respectively. The data obtained reflect the reduction of areas contaminated with eggs of Echinococcus granulosus , which would cause a loss in immunity against this parasite after a certain time. Prevalence of larvae T. hydatigena and T. ovis could change if more sites were
* Corresponding author E-mail address: [email protected] (P.A. Cabrera). 0001-706X/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved. PII: S 0 0 0 1 - 7 0 6 X ( 0 2 ) 0 0 2 1 4 - 0
282
P.A. Cabrera et al. / Acta Tropica 85 (2003) 281 /285
considered, a fact that was confirmed in studies carried out in our country. The species O. aries must be used as an indicator in the control programmes, especially in the category of 2 /4 teethed lambs. The fact they are not as frequent in our market must be considered; in 1998 they accounted for only 3.0% of the total numbers of animals. # 2002 Elsevier Science B.V. All rights reserved. Keywords: Prevalence; Echinococcus granulosus ; Sheep; Uruguay
1. Introduction Echinococcus granulosus is endemic in Uruguay. Its biologic cycle causes a cyclo-zoonotic infection impacting on public health and animal production, with ensuing consequences on the meat industry. As occurs with other helminths, E. granulosus has a negative binomial distribution in its definitive and intermediate hosts, and only a very small number of animals host large burdens of parasites (Gemmell and Lawson, 1986; Ming et al., 1992; Roberts et al., 1987). Consistent with those factors, studies aimed at establishing infection rates and intensity should be performed in sheep, since these are the most sensitive markers of the degree of environmental contamination caused by the eggs of the agents producing the hydatid disease (Cabrera et al., 1995). The economy based on cattle raising reports important losses due to the seizure of offal with parasites, an activity carried out by the Veterinary Inspection Service (Ministry of Agriculture), which generates the data that feed an information system providing feedback to the health control campaigns developed by the official agencies (Sadykhov and Melikor, 1965; Inderkum et al., 1987; Bonifacino et al., 1995; Orlando et al., 1999). Slaughtering operations are regulated by the number of animals in the slaughtering lot, circulation, rate, morphologic features of the specimens, location sites of the parasites within the organs, developmental status of the metacestodes and other parasitic forms, as well as other confounding conditions. Therefore, diagnostic tasks were coordinated in the slaughter plants and the laboratory in 1994, in order to determine the national prevalence of larval echinococcosis in sheep of all categories, resulting in decidual teeth animals, 2.3%; 2 /4 teethed animals: 15.2%; and 6 /8 teethed
animals: 33.9%, with an overall figure for sheep of 16.2% (Cabrera et al., 1989, 1991, 1996). The second study assessing the prevalence of echinococcal larvae in sheep in the slaughtering plants was performed in 1998 and it was designed to estimate the existing prevalence levels in each age group. These data enable us to evaluate the effectiveness of the control actions applied by the National Plan against Hydatidosis (Orlando et al., 1995) and contribute to the improvement of the health information systems for epidemiological surveillance.
2. Materials and method The work included sheep (Ovis aries ), using a random sample for the category including lambs (2 /4 teeth) with E /2% and Z /95%, and adults (6 /8 teeth) with E /3% and Z /95%, drawing sheep from the plants major slaughterhouses in the country. Of the 2035 animals studied, 1019 were lambs and 1016 were adults. Offal of the first 22 animals in each herd were examined, by origin and category; special care was taken to avoid repeating the slaughter plants of origin. After removing and labeling the specimens, they were processed at the laboratory by making a series of 3/5 mm, wide sections of the liver, lungs, spleen, kidneys and heart. The main data collected included number of cysts per animal, anatomic site, viability and fertility (Lloyd et al., 1991). To differentiate hydatid cysts from cysticerci of Taenia hydatigena or T. ovis and from Corynebacterium pseudotuberculosis abscesses, histopathologic studies were performed in those lesions in which the gross examination was questionable, and in those requiring confirmation because of their small size.
P.A. Cabrera et al. / Acta Tropica 85 (2003) 281 /285
The fertility of the E. granulosus cysts were determined to be fertile by demonstration of protoscolices, and the viability of the latter was assessed with the eosin exclusion test. The heart was sectioned and examined to rule out parasites, particularly T. ovis .
3. Results The prevalence of hydatid larvae in 2/4 teeth sheep was 7.7% and in those with 6/8 teeth it was 18.0%. The prevalence with liver location was 8.50%, and in the lungs it was 8% for all the animals (Tables 1 and 2). In younger animals, 29% of the larval cysts (hydatids) were calcified and 71% were hyaline. By comparison, in adult animals, 34.4% were calcified and 65.6 were hyaline (Table 3). Other parasitic conditions found in the hepatic parenchyma were larvae of T. hydatigena (5.06%), white stain (0.8%), caseous lymphadenitis (3.04%), abscesses (0.4%), lesions caused by Fasciola hepatica (4.0%) and larvae of T. ovis in the cardiac muscle (1.8%; Table 4).
4. Discussion Previous surveys carried out using the same methodology in 1994 documented prevalence of 15.2% for the 2/4 teethed animals and 33.9% in 6/ 8 teethed animals, which indicates a decrease of 49.6 and 47.0%, respectively.
283
The data obtained indicate reduction in the areas contaminated with eggs of E. granulosus , which in time will lead to a loss of immunity against the parasite. The intensity of the infection in individual animals was seen to increase with age, which implies that the number of eggs swallowed and the frequency of their ingestion are too low to maintain an effective immunity. The prevalence data collected on larval T. hydatigena and T. ovis infections could vary if more animals in more locations were considered, something that was confirmed in studies carried out in Uruguay. The larvae of T. hydatigena (Cisticercus tenuicollis ) and T. ovis (C. ovis ) show a number that indicates that the sheep have acquired immunity for re-infection. Visceral caseous lymphadenitis is common in our country, and it should be taken into account since it can distort the prevalence curves of E. granulosus , and differential diagnoses must be established by slice and culture of the lesions.
5. Conclusion The data obtained document a significant decrease in E. granulosus infection in livestock since the 1994 /1998 period, when intense actions were implemented to eliminate tapeworm parasites from dogs with praziquantel a nation-wide programme, reducing the areas contaminated with eggs. This was expected to lead to the loss of immunity of intermediate hosts to the parasite after a certain time. The data regarding larval T.
Table 1 Number and percentage of animals presenting E. granulosus by age categories and site of the larvae Categories (number of teeth)
Total
Number of animals with parasites Total number
Sites
Total
Livers
N
%
N
Lungs %
N
%
Total
2035
261
12.8
173
8.5
163
8.0
Lambs (2 /4) Adults (6 /8)
1019 1016
78 183
7.65 18.01
53 120
5.2 11.81
44 119
4.31 11.71
P.A. Cabrera et al. / Acta Tropica 85 (2003) 281 /285
284
Table 2 Larval echinococcosis per category and organ Category (teeth)
Liver
Lung
Liver/lung
Total Positive
% Negative
Total
2 /4 6 /8
34 64
25 63
19 56
78 183
941 833
1019 1016
7.65 18.01
Total
98
88
75
261
1774
2035
12.81
Table 3 Morphologic characteristics of the hydatic larvae Lambs (2 /4 teeth)
Hyaline Calcified
Adults (6 /8 teeth)
Liver
Lung
Total
%
Liver
Lung
Total
%
32 19
39 10
71 29
71 29
49 44
75 21
124 65
65.6 34.4
References
Table 4 Infections and various conditions found in the viscera
Larval T. hydatigena Larval T. ovis F. hepatica Caseous lymphadenitis Abscesses White stain
2 /4
6 /8
Total
%
42 17 24 23 3 11
60 16 56 39 5 5
102 33 80 62 8 16
5.01 1.62 3.93 3.04 0.39 0.78
hydatigena and T. ovis could increase in prevalence if more frequent anatomic sites like head, neck and limb muscles were examined. The number and prevalence of other conditions that could be mistaken for larval cestodes require the use of this type of methodology that includes laboratory diagnosis, although it is not applicable at an industrial level. Infection in sheep (O. aries ) should be used as an indicator of progress in control programmes, especially in animals in the 2/4 teeth category. In practice, however, sheep of this age are not frequent in our market, accounting for only 3.0% of the national slaughter in 1998. Thus, obtaining a high number in animals at that age for the study may be difficult.
Bonifacino, R., Giacoia, A., Murillo, N., Orlando, D., Perdomo, R., 1995. Situacio´n de la hidatidosis en el Uruguay. Memorias de la reunio´n del Grupo cientı´fico sobre avances en la prevencio´n, control y tratamiento de la Hidatidosis, Montevideo, Uruguay, Octubre 26 /28, 1995. Pan American Health Organization, pp. 242 /276. Cabrera, P.A., Parietti, S., Lo´pez, J., Sampaio, I., 1989. Hidatidosis intraparenquimatosa con procesos fe´rtiles en categorı´as jo´venes de ovinos y suinos. Taller Internacional de Investigacio´n Ba´sica en Helmintos. 2 do. Taller Regional de Investigacio´n Ba´sica en Hidatidosis, Solı´s, Uruguay, p. 142. Cabrera, P.A., Parada, L., Barcelona, C., Burgues, C., Acun˜a, A., Paolillo, E., Agulla, J., Camejo, G., Ramos, M., 1991. Hidatidosis en el a´rea rural: estudio simulta´neo en tres hospederos. Capı´tulo ovinos. X Congreso Latinoamericano de Parasitologı´a, Montevideo, Uruguay, p. 362. Cabrera, P.A., Hara´n, G., Benavides, U., Valledor, S., Perera, G., Lloyd, S., Gemmell, M.A., Baraibar, M., Moran˜a, A., Maissonave, J., Carballo, M., 1995. Transmission dynamics of Echinococcus granulosus , Taenia hydatigena and Taenia ovis in sheep in Uruguay. Int. J. Parasitol. 35 (7), 807 /813. Cabrera, P.A., Irabedra, P., Trindade, J., Agulla, J., Heinzen, T., Alvarez, M., Elola, S., Sambra´n, Y., Moran˜a, A., Orlando, D., Lazaneo, H., 1996. Determinacio´n de la prevalencia de la hidatidosis ovina nacional en playas de faena, Uruguay. Hidatidosis 2, 18 /28. Gemmell, M.A., Lawson, J.R., 1986. Epidemiology and control of hydatid disease. In: Thompson, R.C. (Ed.), The Biology
P.A. Cabrera et al. / Acta Tropica 85 (2003) 281 /285 of Echinococcus and Hydatid Disease. George & Unwin, London, pp. 189 /216. Inderkum, R., Perdomo, E., Serna, M., Paullier, C., 1987. Estudio de la patologı´a hepa´tica en establecimientos de faena. Patologı´a hepa´tica ovina: corderos y borregos. IV Congreso Nacional de Veterinaria. SMVU, Montevideo, Uruguay. Lloyd, S., Martin, SC., Walters, T.M.H., Soulsby, E.J.L., 1991. Use of sentinel lambs for early monitoring of the South Powys Hydatidosis Control Scheme: prevalence of Echinococcus granulosus and some other helminths. Vet. Rec. 129, 73 /76. Ming, R., Tolley, H.D., Andersen, F.L., Chai, J., Sultan, Y., 1992. Frecuency distribution of Echinococcus granulosus in sheep populations in the Xinjiang Uygur Autonomous Region, China. Vet. Parasitol. 43, 233 /241.
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