DISTRIBUCIÓN GEOESPACIAL DE LA TOXOPLASMOSIS CAPRINA EN ELESTADO DE VERACRUZ
Capítulo de libro publicado. Libro: El Agro Veracruzano 2015 ISBN: 978-607-96939-2-3
62
CAPÍTULO III
8. CAPÍTULO DE LIBRO 2
EPIDEMIOLOGÍA DE LA TOXOPLASMOSIS CAPRINA EN VERACRUZ, MÉXICO
Capítulo de libro publicado.
Libro: INNOVANDO EL AGRO VERACRUZANO 2016 ISBN: 978-607-715-331-3
78
CAPÍTULO IV
9. CAPÍTULO DE LIBRO 3
IDENTIFICACIÓN MOLECULAR DE Toxoplasma gondii EN LECHE DE CABRAS EN MUNICIPIOS DE VERACRUZ
Capítulo de libro publicado.
Libro: Avances en Investigación Agrícola, Pecuaria, Forestal, Acuícola, Pesquería, Desarrollo rural, Transferencia de tecnología, Biotecnología, Ambiente, Recursos naturales y Cambio Climático.
85
CAPÍTULO V
Seroepidemiology and risk factors associated with caprine toxoplasmosis in Veracruz, México
Artículo enviado.
Revista: Journal of Veterinary Research Factor de impacto: 0.8115
86 Seroepidemiology and risk factors associated with caprine toxoplasmosis in
Veracruz, México
Javier C. Huerta-Peña1, *David I. Martínez-Herrera1, Violeta T. Pardío-Sedas1, Carlos
R. Cruz-Vázquez2, José J. Murguía-González3, José A. Villagómez-Cortes1, Gabriela R. Hernández-Carbajal1, Ricardo Flores-Castro4
1 Universidad Veracruzana. Facultad de Medicina Veterinaria y Zootecnia.
Circunvalación esq. Yañez s/n, Col. Unidad Veracruzana, 91710, Veracruz, México.
2 Instituto Tecnológico El Llano Aguascalientes. Km. 18 carretera Aguascalientes a
San Luis Potosí, El Llano, 20110, Aguascalientes, México.
3 Universidad Veracruzana. Facultad de Ciencias Biológicas y Agropecuarias. Peñuela Amatlán s/n, Col. Centro, Amatlán de los Reyes, 94945, Veracruz, México.
4 CENID Microbiología Animal-INIFAP, km 15.5 Carretera México-Toluca, Col. Palo Alto, 05110, Ciudad de México.
Abstract
Toxoplasmosis is a zoonosis of global distribution caused by the protozoan Toxoplasma gondii. Since related information about goat toxoplasmosis in the state of
Veracruz, Mexico is scarce, no background data is available to support related health policies and to dictate adequate preventive measures. The objective of this study was to determine the seroprevalence of Toxoplasma gondii in goats from the central region of the state of Veracruz, Mexico, as well as to identify possible risk factors associated with seropositivity. Four hundred and eighty-three females older than 3 months and 73 bucks from 81 goat farms distributed in fourteen municipalities of the study area were
87 included in the study. Samples were processed using the indirect ELISA test to identify the presence of anti-T. gondii antibodies. The possible association between seroprevalence and some potential risk factors was estimated. The overall seroprevalence was 36.7% (204/556; 95%CI:32.7-40.9), where positive animals were
found in 80% of farms and in all municipalities included in the study. Caprine risk factors were observed: goats from the municipalities of Yecuatla (OR=3.4; 95%CI:1.7-
7.1), Tlacolulan (OR=3.4; 95%CI:1.7-6.6), Chiconquiaco (OR=3.1; 95%CI:1.5-6.4),
Coatepec (OR=2.4; 95%CI: 1.2-4.5), and Xico (OR=1.7; 95%CI:1.1-3.1), goats from
another state (OR=1.4; 95%CI: 1.1-2.1), lactating females (OR=2.7; 95%CI:1.9-3.9),
goats between 25 and 37 months old (OR=1.9; 95%CI: 1.2-3) and goats between 38 and
50 months old (OR=2.9; 95%CI: 2.0-4.3). It is concluded that the general
seroprevalence in the central region of the state of Veracruz, Mexico is high, and it is associated with several risk factors.
Keywords: Toxoplasma gondii, seroprevalence, risk factors, Mexico.
Introduction
Toxoplasmosis is a parasitic disease caused by the protozoan Toxoplasma gondii, of an indirect biological cycle and zoonotic character that is widely distributed throughout the world. Cats and other wild cats are the ultimate hosts and a wide variety of mammals and birds may act as intermediary hosts, including man1, 2. Toxoplasmosis is important in public health and affects goat-breeding farmers because unpasteurized milk and raw or poorly cooked meat infected with the parasite is an important route of transmission to humans3. Goat cattle can acquire the infection by water drinking or pastures contaminated with sporulated oocysts that were shed by
88 cats or other wild cats, or transplacentally4. In Mexico, toxoplasmosis in domestic and
wild animals has a wide distribution5; however, in the case of goats, there are few studies concerning their epidemiological situation6, 7, 8, 9.
The objective of the present study was to determine the seroprevalence against to T. gondii in goats in the state of Veracruz, Mexico, as well as to identify possible risk
factors associated with seropositivity. Materials and Methods
Study Area
This study was carried out in goat farms located in fourteen municipalities in the central region of the Veracruz state of, Mexico (Figure 1). The municipalities included in the study range from 885 to 2,400 masl; the dominant climate is the regular humid temperate, except in the municipality of Perote, in which the dry cold climate predominates. The average annual temperature of the area is 18° to 22°C.
89 Farm Characteristics
Eighty one goat farms were included in the study and distributed in 14 municipalities of the central region of the state of Veracruz. Approximately 90% of the state's goat stock is concentrated in this region. Production systems used in farms are diverse and range from technical confinement systems to extensive grazing systems, as well as some cases of communal grazing areas at the family level. Most systems have a low use of technology and are focused on milk production, even though a few are devoted
90 to meat production. The predominant breeds are Saanen, Nubia, and crossbred animals of an indefinite biotype, which represents the majority of the animals. Feeding is supported by grazing in native pastures and supplementation occurs only in animals that are milked. Reproductive management includes the use of purebred bucks and births occur throughout the year; drinking water comes from natural sources (streams and springs), either supplied in communal drinking water or drinked directly from the field during grazing. It is common to observe the presence of other domestic animals species in the farms, mainly dogs, cats, horses and dairy cattle.
Sampling
A total of 556 animals were included in the study, considering all females from three months of age on and all bucks present in each farm. Offspring lesser than three months were excluded to avoid interference in the diagnosis due to passive immunity by ingestion of colostrum antibodies. The minimum number of samples to be collected was calculated assuming 50% prevalence, a 95% confidence interval and a 5% error10. Blood samples from each animal were obtained by puncture of the jugular vein with new vacutainer equipment without anticoagulant. Samples were transported at 4°C to the laboratory where they were centrifuged at 1,000 x g for 15 minutes to extract the serum, which was stored in Eppendorf® tubes at -20 ° C until use in the serological test.
Serological diagnosis
A commercial indirect ELISA test (Chekit Toxotest. IDEXX Laboratorios Inc., Westbrook., ME, USA) was used. Sera was diluted to 1:400 to discriminate negative samples from positives according to the manufacturer's instructions. The reading was performed at 450 nm and the results were processed with software supplied by the
91 manufacturer (CHEKIT). A sample with a cut-off point equal to or greater than 30% was considered positive, as indicated by the manufacturer's instructions. The test identifies the antigen p 30 of T. gondii and has a sensitivity of 90.5% and a specificity of 97.8%.
Survey
Two written questionnaires with open and closed questions were designed and applied to the farms owners participating in the study. One questionnaire was applied to every herd and the second one was utilized to collect individual data from each animal included in the study. Both questionnaires helped to identify some variables that could be considered as potential risk factors, such as age, sex, productive status, municipality, origin or provenance of animals, presence of other domestic animals including cats, water source, and presence of abortions.
Statistical analysis
Seroprevalence was determined considering the following variables: age range, sex, productive status, farm location in the 14 municipalities, origin of animals, presence of other domestic animals, water source and presence of abortions. To determine the association between seroprevalence and each of the variables considered as potential risk factors, the Odds Ratio (OR)10 was calculated using Win Episcope Ver. 2.011.
Values above 1 indicated association considering for the interpretation of risk at 95% confidence intervals. Chi-square test (p <0.05) was used to test for statistical significance.
Results
The overall seroprevalence was 36.7% (204/556; 95%CI: 32.7–40.9) (Table 1). Positive
92 the farms (Table 1), in which seroprevalence ranged from 11.1 to 100%. These farms contributed with 83% of the animals included in the study. All the farms that were taken into account in the study had cats present. In the goats, the seroprevalence was 38.2% (184/482; 95%CI: 33.8-42.7), whereas in the bucks was 27% (20/74; 95%CI:
17.7-38.8).
Table 1: Prevalence of caprine toxoplasmosis in municipalities in the central area of
the state of Veracruz, Mexico by indirect ELISA test.
Prevalence Total Positive Prevalence (%) *95%CI
General 556 204 36.7 32.7-40.9
By municipality 14 14 100 73.2-100
By herd 81 65 80.3 69.6-87.9
*95%CI= 95% Confidence Interval
Seroprevalence, according to the productive status of the goats is shown in the Table 2, where it can be seen that it was in a range of 12.1 to 51.2%. By age group (Table 2), prevalence ranged from 13.6% (3 to 6 months old) to 54.5% (38 to 50 months old age). As for the municipalities (Table 2), the seroprevalence ranged from 10.2% (municipality of Villa Aldama) to 64.7% (municipality of Yecuatla).
Variables identified as statistically significant risk factors were: animals originating in another state of the country (OR, 1.4; 95%CI: 1.1-2.1, P = 0.03), lactating goats (OR,
2.7; 95%CI: 1.9-3.9, P = 0.00), animals between 25 and 37 months old (OR, 1.9; 95%CI:
1.2-3, P = 0.01) and animals between 38 and 50 months old (OR, 2.9; 95%CI: 2-4.3, P
93 1.7–7.1, P = 0.00), Tlacolulan (OR, 3.4; 95%CI: 1.7–6.6, P = 0.00), Chiconquiaco (OR,
3.1; 95%CI: 1.5–6.4, P = 0.00), Coatepec (OR, 2.4; 95%CI: 1.2– 4.5, P = 0.02), and Xico
(OR, 1.7; 95%CI: 1.1–3.1, P = 0.16).
It was not possible to identify an association between seroprevalence and other potential risk factors considered in the risk analysis because farms had similar management and sanitary conditions.
Table 2: Prevalence and risk factors associated with caprine toxoplasmosis from
animals in the central area of the state of Veracruz, Mexico. Variable Number of
Animals
Positive
Animals
Prevalence *95%CI *OR *95%CI P-value
Origin/Provenance Veracruz 386 131 34.0 29.4 – 39.0 0.6 0.4 – 0.9 0.03 Other State 170 73 42.9 35.5 – 50.8 1.4 1.1 – 2.1 0.03 Stage Does 34 4 11.8 3.9 – 29.1 0.2 0.1 – 0.6 0.00 Pregnant 55 20 36.4 24.1 – 50.5 1.0 0.6 – 1.8 0.92 Suckling 111 45 40.5 31.5 – 50.3 1.2 0.8 – 1.9 0.40 Doeling 84 20 23.8 15.5 – 34.6 1.2 0.8 – 1.9 0.01 Lactating 171 87 50.9 43.1 – 58.6 2.7 1.9 – 3.9 0.00 Dry 27 8 29.6 14.5 – 50.3 0.7 0.3 – 1.7 0.56 Bucks 74 20 27.0 17.7 – 38.8 0.6 0.3 – 1.0 0.08 Age
94 3 – 6 44 6 13.6 5.7 – 28.0 0.3 0.1 – 0.6 0.00 7 – 12 97 17 17.5 10.8 – 26.9 0.3 0.2 – 0.5 0.00 13 – 24 85 22 25.9 17.3 – 36.7 1.7 0.9 – 2.8 0.03 25 – 37 83 41 49.4 38.3 – 60.5 1.9 1.2 – 3.0 0.01 38 – 50 167 91 54.5 46.6 – 62.2 2.9 2.0 – 4.3 0.00 >50 80 27 33.8 23.8 – 45.3 1.1 0.7 – 1.8 0.63 Municipality Yecuatla 34 22 64.7 46.5 – 79.7 3.4 1.7 – 7.1 0.00 Tlacolulan 39 24 64.1 47.1 – 78.3 3.4 1.7 – 6.6 0.00 Chiconquiaco 32 20 62.5 43.8 – 78.3 3.1 1.5 – 6.4 0.00 Coatepec 41 22 56.1 39.9 – 71.1 2.4 1.2 – 4.5 0.02 Xico 49 23 48.9 34.6 – 63.5 1.7 1.1 – 3.1 0.16 Ixhuacán 26 12 46.2 27.1 – 66.3 1.5 0.7 – 3.3 0.41 Tatatila 39 17 43.6 28.2 – 60.2 1.4 0.7 – 2.6 0.45 Las Vigas 40 17 42.5 27.4 – 59.0 1.3 0.7 – 2.5 0.53 Las Minas 33 11 33.3 18.6 – 51.9 0.9 0.4 – 1.8 0.82 Coacoatzintla 36 10 27.8 14.8 – 45.4 0.6 0.3 – 1.4 0.33 Emiliano Zapata 34 8 23.5 11.4 – 41.6 0.5 0.2 – 1.2 0.14 Jalacingo 33 5 15.2 5.7 – 32.7 0.3 0.1 – 0.8 0.01 Perote 71 8 11.3 5.3 – 21.5 0.2 0.1 – 0.4 0.00 Villa Aldama 49 5 10.2 3.8 – 23.0 0.2 0.1 – 0.5 0.00
95 *95%CI= 95% Confidence Interval, OR= Odds Ratios, Yates-corrected Chi-square (P-
value<0.05).
Discussion
The general seroprevalence obtained in this study (36.7%; 95%CI: 32.7-40.9) shows
that more than a third of the goats have been exposed to the agent in the study area where more 90% of the total goat stock of the state of Veracruz is concentrated (Table 1). This a paramount situation of great relevance since this as a corridor that keeps toxoplasmosis circulating among these municipalities because farms share many grazing areas. In addition, the relationship between cat behavior and soil contamination is modulated by local conditions such as the regular humid temperate climate with steady temperatures between 18° and 22 °C. Such conditions are influencing the survival of the oocysts12. In addition, production systems are very
similar, because most are semi-intensive, and this favors the dissemination and presence of Toxoplasma gondii in the study area9.
Animals belonging to the municipalities of Yecuatla, Tlacolulan, Chiconquiaco, Coatepec, Xico, were identified as risk factors associated with the presence of caprine toxoplasmosis. Other authors mentioned that strict herbivores as small ruminants acquire the infection from soil because the protozoan may survive over a year and sharing grazing areas with other herds or species is a common practice6, 13. The risk of disseminating and contracting the infectious agent is increased by closeness between farms and the affected municipalities, similar production systems and climatic conditions in 13 of 14 municipalities studied. Toxoplasmosis is a zoonosis where
96 intermediate levels of pollution are expected to be frequent in the rural environment; meanwhile, cat density is intermediate and territoriality is more pronounced14.
The purchase or acquisition of animals from another state also resulted as a risk factor (OR, 1.4 95%CI: 1.1 – 2.1, P = 0.03) (Table 2). Incoming animals from another state
lacking a negative diagnostic test to Toxoplasma gondii at the time of purchase is one of the main contributing factors to disease transmission. Among these, positive females are particularly risky because they can disseminate the protozoan transplacentally or even through milk, and be a source of infection for both, young animals and humans15.
Lactating females resulted as a risk factor (OR, 2.4 95%CI: 1.6 - 3.4, P = 0.00) (Table
2). The fact that most goats are at this stage of production may have an important impact on public health because it is a zoonosis of great relevance. Consumption of dairy products or by-products contaminated with tachyzoites removed from the infected goats in production may become a serious problem for the exposed population since they are very resistant to incomplete pasteurization. In addition to this, products and by-products of goat origin in the study region are elaborated in an artisan way posing a problem for public health, since consumers may acquire the parasite by this route and significantly increase the prevalence of toxoplasmosis in humans16.
Also, goats that are in the range of 25 to 37, and from 38 to 50 months old were found to be a risk factor (Table 2). Older animals are often a risk factor because they have been exposed a longer time to the etiological agent found in the environment, and are also more likely to acquire it than young animals17.
97 Conclusion
Caprine toxoplasmosis is a disease that is widely distributed in the 14 municipalities studied in the central area of the state of Veracruz, as in other countries. In addition, the animals belonging to the municipalities of Yecuatla, Tlacolulan, Chiconquiaco, Coatepec and Xico were identified as risk factors associated with the presence of goat toxoplasmosis. Animals coming from other states, lactating females and goats in the range of 25 to 50 months old were also recognized as risk factors.
Acknowledgments
Authors thank the SIPECAV goat farmers union of Veracruz and to the FUNPROVER (Project code 30-2009-0896) Foundation grant for their kindness, help and the cooperation provided. Authors also thank goat farmers that allowed them to sample their herds.
References
1. Dubey JP. Toxoplasmosis of animals and humans. 2nd ed. Boca Raton: CRC Press; 2010. 1-6.
2. Innes EA. A brief history and overview of Toxoplasma gondii. Zoonoses Public Health. 2010; 57(1):1-7.
3. Hill DE, Chirukandoth S, Dubey JP. Biology and epidemiology of Toxoplasma gondii in man and animals. Anim Hlth Res Rev. 2005; 6(1): 41-61.
4. Dubey JP, Lindsay DS. Neosporosis, Toxoplasmosis and Sarcocystosis in ruminants. Vet Clin North Am Food Anim Pract. 2006; 22(3): 645-671.
5. Hernández-Cortaza, I; Acosta-Viana KY; Ortega-Pacheco A, Guzman-Marin, ES, Aguilar-Caballero AJ, Jiménez-Coello M. Toxoplasmosis in Mexico:
98 Epidemiological situation in humans and animals. Rev Inst Med Trop Sao Paulo. 2015; 57(2): 93-103.
6. García-Vazquez Z, Rosario-Cruz R, Solorzano-Salgado M. Prevalence of antibodies against Toxoplasma gondii in sheep and goats in three states of Mexico. Prev Vet Med. 1990; 10(1-2): 25-29.
7. Alvarado-Esquivel C, García-Machado C, Vitela-Corrales J, Villena I, Dubey JP. Seroprevalence of Toxoplasma gondii infection in domestic goats in Durango State, Mexico. Vet Parasitol. 2011; 183: 43-46.
8. Alvarado-Esquivel C, Silva-Aguilar D, Villena I, Dubey JP. Seroprevalence of Toxoplasma gondii Infection in Dairy Goats in Michoacán State, Mexico. J
Parasitol. 2013; 99(3): 540-542.
9. Aguilar DM, Romero SD, Pardío SV García VZ, Correa BD, Caballero OH, Olea PF, Salman M. Risk factors associated with Toxoplasma gondii infection in goats and producers in Yecuatla, Veracruz. Proceedings of the 56th Annual Meeting of the American Association of Veterinary Parasitologists. July 16th -19th St. Louis, Missouri, USA. 2011.
10. Thrusfield M. Veterinary Epidemiology. 3rd edition. Blackwell Science, Oxford, England, 600 p. 2005.
11. Thrusfield M., Ortega C., de Blas I., Noordhuizen J.P., Frankena K. 2001. Win Episcope 2.0: Improved epidemiological software for veterinary medicine. Vet Rec. 148(18): 567-572.
12. Afoso E, Lemoine M, Poulle ML, Ravat MC, Romand S, Thulliez P, Villena I, Aubert D, Rabilloud M, Riche B, Gilot-Fromont E. Spatial distribution of soil
99 contamination by Toxoplasma gondii in relation to cat defecation behaviour in an urban área. Int J Parasitol. 2008; 38(8-9): 1017–1023.
13. Cruz-Vazquez C, Garcia-Vazquez Z, Rosario-Cruz R, Solorzano-Salgado M. Ovine toxoplasmosis in Huitzilac, Morelos, Mexico. Prev Vet Med. 1992; 12:27- 33.
14. Turner DC, Bateson PB. The Domestic Cat: The Biology of Its Behaviour. Cambridge University Press. 2000.
15. Dubey JP. Review of Neospora caninum and neosporosis in animals. Korean J Parasitol. 2003; 41(1):1-16.
16. Senyael SE, Eliona KJ. A survey of Toxoplasma gondii antibodies by latex agglutination assay in dairy goats in Northern Tanzania. Trop Anim Hlth Prod. 2012; 45(1):211-217.
17. Carneiro ACAV, Carneiro M, Gouveia AMG, Guimaraes AS, Marques APR, Vilas-Boas LS, Vitor RWA. Seroprevalence and risk factors of caprine toxoplasmosis in Minas Gerais, Brazil. Vet Parasit. 2009; 160(3-4):225-229.
100 Distribución geoespacial de la toxoplasmosis en caprinos del estado de Veracruz, México
Artículo enviado.
Revista: Revista Mexicana de Ciencias Pecuarias Factor de impacto: 0.768
101 DISTRIBUCIÓN GEOESPACIAL DE LA TOXOPLASMOSIS EN CAPRINOS