Publicação
Prevalence and risk factors for Toxoplasma gondii infection in black and white Merino lambs in Alentejo, Portugal
| Resumo: | Toxoplasma gondii is one of the most common zoonotic parasites worldwide. The infection in sheep is a concern for animal and public health and also has an important economic impact in the sheep industry. Human infection is particularly dangerous in its congenital form and in people with immunological deficiency. Toxoplasmosis may be acquired through the consumption of raw or undercooked meat containing T. gondii tissue cysts and lamb meat is generally considered a main source of human infection. There are few studies on animal toxoplasmosis in Portugal, therefore this study aimed to contribute to the knowledge on this parasitosis, by determining the prevalence and risk factors for T. gondii infection in black Merino and white Merino lambs in the region Alentejo. A total of 330 sera from Merino lambs collected in 22 different farms in the Alentejo region were analyzed. Samples were obtained in the scope of Project MERINOparasite PTDC/CVT-CVT/28798/2017 and made available for the purpose of the present study. Screening of antibodies to T. gondii was performed by means of a Direct Agglutination Test (DAT) (Toxoscreen DA, bioMerieux), an Enzyme-Linked Immunosorbent Assay (ELISA) (ID Screen Toxoplasmosis Indirect Multispecies, IDvet) and an in-house Indirect Fluorescent Antibody Test (IFAT). The percentage of seropositive animals by the three techniques was 7.0% (23/330), 0.9% (3/330) and 7.9% (26/330) respectively. The variables age, sex, breed and presence of cats on the farm, assessed as potential risk factors, did not show a statistically significant relationship with the occurrence of infection, apart from the variable breed that demonstrated to be significant according to IFAT. The results obtained show a low level of exposure of Merino lambs to T. gondii. Hence, the consumption of meat from Merino lambs reared in extensive production systems in the Alentejo region may represent a low risk for human infection in Portugal. Data from the present study may be valuable as input data for quantitative source attribution models for food-borne toxoplasmosis to measure the likely contribution of lamb meat as a source of human infection. |
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| Autores principais: | Almeida, Francisca Raposo de |
| Assunto: | Merino Lambs Toxoplasma gondii Prevalence Serology Merino Borregos Toxoplasma gondii Prevalência Serologia |
| Ano: | 2022 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Toxoplasma gondii is one of the most common zoonotic parasites worldwide. The infection in sheep is a concern for animal and public health and also has an important economic impact in the sheep industry. Human infection is particularly dangerous in its congenital form and in people with immunological deficiency. Toxoplasmosis may be acquired through the consumption of raw or undercooked meat containing T. gondii tissue cysts and lamb meat is generally considered a main source of human infection. There are few studies on animal toxoplasmosis in Portugal, therefore this study aimed to contribute to the knowledge on this parasitosis, by determining the prevalence and risk factors for T. gondii infection in black Merino and white Merino lambs in the region Alentejo. A total of 330 sera from Merino lambs collected in 22 different farms in the Alentejo region were analyzed. Samples were obtained in the scope of Project MERINOparasite PTDC/CVT-CVT/28798/2017 and made available for the purpose of the present study. Screening of antibodies to T. gondii was performed by means of a Direct Agglutination Test (DAT) (Toxoscreen DA, bioMerieux), an Enzyme-Linked Immunosorbent Assay (ELISA) (ID Screen Toxoplasmosis Indirect Multispecies, IDvet) and an in-house Indirect Fluorescent Antibody Test (IFAT). The percentage of seropositive animals by the three techniques was 7.0% (23/330), 0.9% (3/330) and 7.9% (26/330) respectively. The variables age, sex, breed and presence of cats on the farm, assessed as potential risk factors, did not show a statistically significant relationship with the occurrence of infection, apart from the variable breed that demonstrated to be significant according to IFAT. The results obtained show a low level of exposure of Merino lambs to T. gondii. Hence, the consumption of meat from Merino lambs reared in extensive production systems in the Alentejo region may represent a low risk for human infection in Portugal. Data from the present study may be valuable as input data for quantitative source attribution models for food-borne toxoplasmosis to measure the likely contribution of lamb meat as a source of human infection. |
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