Departamento de Zootecnia, Engenharia Rural e Veterinária (DZERV)
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Percorrer Departamento de Zootecnia, Engenharia Rural e Veterinária (DZERV) por autor "Almeida, Daniela"
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- A 2-Year Longitudinal Seroepidemiological Evaluation of Toxoplasma gondii Antibodies in a Cohort of Autochthonous Sheep from Central PortugalPublication . Almeida, Daniela; Quirino, João; Barradas, Patrícia Ferreira; da Silva, Priscilla Gomes; Pereira, Maria; Cruz, Rita; Santos, Carla; Mega, Cristina; Esteves, Fernando; Nóbrega, Carmen; Vala, Helena; Gärtner, Fátima; Amorim, Irina; Mesquita, João R.Background: Toxoplasma gondii is an important zoonosis and one of the major causes of abortion in sheep worldwide. (2) Methods: We performed a 2-year longitudinal serological antiT. gondii IgG screening on a cohort of a spatially confined population of a Portuguese autochthonous sheep breed in central Portugal. (3) Results: From the screening of the 2015 and 2016 sera, an increase of seroprevalence was observed (57.7% (95% CI: 49.9–65.3%) versus 69.1% (95% CI: 61.5–75.9), from 2015 and 2016, respectively) (p = 0.031). (4) Conclusions The present study is the first to provide prospective data on the anti-T. gondii serological status of a sheep cohort in Portugal, showing an increase in the occurrence of T. gondii. There is a need to provide a clearer understanding of T. gondii epidemiology in Portugal, ideally by implementing monitoring programs on sentinel herds, not only due to the high impact of T. gondii on animal health but also for it being a zoonosis.
- Molecular Screening of Sarcocystis spp. in Grazing Sheep (Ovis aries) and Shepherd Dogs (Canis lupus familiaris) from Central PortugalPublication . Gomes-Gonçalves, Sara; Figueiredo, Ricardo J.; Rodrigues, Soraia; Bento, Jaqueline T.; Santos-Silva, Sérgio; Almeida, Daniela; Cruz, Rita; Esteve, Fernando; Esteves, Fernando; Baptista, Alexandra Lameira; Pereira, Maria Aires; Cardoso, Luís; Mesquita, João R.Sarcocystis spp. are cyst-forming protozoan parasites with a global distribution that infect a wide range of domestic and wild animals, impacting both animal health and livestock productivity. In sheep, infections can cause clinical disease, reproductive losses, and economic damage, articularly when pathogenic species such as Sarcocystis tenella are involved. Grazing sheep, including breeds such as the Serra da Estrela from central Portugal, are at increased risk due to frequent contact with shepherd dogs, which serve as definitive hosts. Despite their significance, data on the occurrence and distribution of Sarcocystis spp. in Portuguese sheep remain limited. This study analyzed 179 samples collected in central Portugal during 2024, including 41 brain tissues and 88 blood samples from sheep, and 50 stool samples from shepherd dogs, using conventional PCR and bidirectional Sanger sequencing. Sarcocystis sp. closely related to S. tenella was detected exclusively in sheep brain tissue, with a prevalence of 4.9% (2/41; 95% CI: 0.60–16.53), while no parasite DNA was found in blood or dog samples. These results provide the first molecular confirmation of Sarcocystis spp. closely related to S. tenella in Portuguese sheep raised for human consumption and establish baseline data for future epidemiological surveillance and control strategies.
- Prevalence of Toxoplasma gondii Antibodies and Risk Factor Investigation in Portuguese Veterinarians: A Matched Case Control StudyPublication . Almeida, Daniela; Santos-Silva, Sérgio; Pereira, Maria; Santos, Carla; Mega, Cristina; Coelho, Catarina; Nóbrega, Carmen; Esteves, Fernando; Cruz, Rita; Vala, Helena; Mesquita, João R.Background: Toxoplasma gondii is a widespread zoonotic agent that greatly impacts Public Health, being responsible for one of the most important parasitic zoonosis worldwide. T. gondii has a heteroxenous life cycle, with cats being the definitive hosts and all warm-blooded animals, including humans, being intermediate hosts. Veterinary practitioners (VP) may be at a higher risk than the general population for T. gondii infection, as they have direct and daily contact with many animal species. The aim of the present study was to ascertain if VP were more likely to be anti-T. gondii IgG seropositive than the general population, as well as to understand if age, accidents with blood-contaminated sharps (cross-blood contamination), gender, working years, and geographic regions play a role as risk factors for T. gondii infection. For this purpose, a case–control study using archived samples was performed. (2) Methods: A total of 350 veterinary practitioners were tested using a commercial semiquantitative enzyme immunoassay for anti-T. gondii IgG. From the general population, 175 anonymous volunteers (matched with cases by region, age, and gender) were studied for anti-T. gondii IgG. (3) Results: There was no statistical difference found between the presence of anti-T. gondii IgG in practitioners (26%; CI = 21.40–30.60%) and the general population (33.14%; CI = 26.17–40.12%) (p = 0.108). Univariate and multivariate analysis showed that only age (older groups) was found to be associated with a higher prevalence of anti-T. gondii IgG, with significant p values (p < 0.05) for both univariate and multivariate analysis. (4) Conclusions: To the best of our knowledge, this is the first case–control study fully focused on the prevalence of anti-T. gondii IgG in VP in Portugal, showing that there was no significant risk for T. gondii infection in veterinarians exposed daily and repeatedly to different species of animals.
- Prevalence of Toxoplasma gondii Antibodies and Risk Factor Investigation in Portuguese Veterinarians: A Matched Case–Control StudyPublication . Almeida, Daniela; Santos-Silva, Sérgio; Pereira, Maria Aires; Santos, Carla; Mega, Cristina; Coelho, Catarina; Nóbrega, Carmen; Esteves, Fernando; Cruz, Rita; Vala, Helena; Mesquita, JoãoToxoplasma gondii is a widespread zoonotic agent that greatly impacts Public Health, being responsible for one of the most important parasitic zoonosis worldwide. T. gondii has a heteroxenous life cycle, with cats being the definitive hosts and all warm-blooded animals, including humans, being intermediate hosts. Veterinary practitioners (VP) may be at a higher risk than the general population for T. gondii infection, as they have direct and daily contact with many animal species. The aim of the present study was to ascertain if VP were more likely to be anti-T. gondii IgG seropositive than the general population, as well as to understand if age, accidents with blood-contaminated sharps (cross-blood contamination), gender, working years, and geographic regions play a role as risk factors for T. gondii infection. For this purpose, a case–control study using archived samples was performed. (2) Methods: A total of 350 veterinary practitioners were tested using a commercial semiquantitative enzyme immunoassay for anti-T. gondii IgG. From the general population, 175 anonymous volunteers (matched with cases by region, age, and gender) were studied for anti-T. gondii IgG. (3) Results: There was no statistical difference found between the presence of anti-T. gondii IgG in practitioners (26%; CI = 21.40–30.60%) and the general population (33.14%; CI = 26.17–40.12%) (p = 0.108). Univariate and multivariate analysis showed that only age (older groups) was found to be associated with a higher prevalence of anti-T. gondii IgG, with significant p values (p < 0.05) for both univariate and multivariate analysis. (4) Conclusions: To the best of our knowledge, this is the first case–control study fully focused on the prevalence of anti-T. gondii IgG in VP in Portugal, showing that there was no significant risk for T. gondii infection in veterinarians exposed daily and repeatedly to different species of animals.
- Prevalence of Toxoplasma gondii Antibodies in Individuals Occupationally Exposed to Livestock in PortugalPublication . Almeida, Daniela; Quirino, João; Matos, Pedro; Esteves, Fernando; Cruz, Rita; Vala, Helena; Mesquita, João R.Toxoplasmosis is a worldwide zoonotic disease with different and complex routes for transmission. Workers occupationally exposed to animals or raw meat and viscera (WOE) may be at more risk than the general population, however conflicting data exist on the risk of developing toxoplasmosis due to this close contact. To add knowledge to this topic, the aim of the present study was to ascertain if WOE were more likely to be anti-T. gondii IgG seropositive than the general population as well as to study risk factors for T. gondii infection such as professional activity, gender, age, years of work and region. For this purpose, a case–control study using archived samples was setup. A total of 114 WOE (including pig slaughterhouse workers, butchers, veterinarians and farmers) and 228 anonymous volunteers (matched with cases by region, age and gender) were studied for anti-T. gondii IgG. A significantly higher anti-T. gondii IgG occurrence (p = 0.0282) was found in WOE when compared with the general population (72.8% [CI = 64.6–81.0%] versus 60.1% [CI = 54.6–65.6%]). Multivariate analysis showed that WOE of more than 50 years of age were more likely to be seropositive for anti-T. gondii IgG (aOR = 16.8; 95% CI 3.6–77.5; p < 0.001) than those aged less than 50 years. To our knowledge, this is the first case–control study on the prevalence of antiT. gondii IgG in WOE in Portugal, also showing an added risk for T. gondii infection in those exposed to animals or their meat and viscera.
- Toxoplasma Gondii In Shepherds and Cheesemakers – A Case-Control Study on Sheep-Associated Occupational Exposure in Central PortugalPublication . Moreira, Guilherme; Almeida, Daniela; Cruz, Rita; Nóbrega, Carmen; Arede dos Santos, Carla Sofia; Coelho, Catarina; Mega, Cristina; Pereira, Maria; Esteves, Fernando; Vala Correia, Helena Maria; Cardoso, Luís; Lopes, Ana P.; Coelho, Ana C.; Mesquita, João R.Objectives: The primary objective of this study was to determine if workers occupationally exposed (WOE) to sheep, specifically shepherds and cheesemakers in central Portugal, are more likely to be seropositive for anti-Toxoplasma gondii IgG compared to the general population. Additionally, the study aimed to explore potential differences in seropositivity between shepherds and cheesemakers, while evaluating age, gender, and activity as possible risk factors for T. gondii infection. Methods: A total of 96 WOE, including 21 shepherds and 75 cheesemakers, were tested for anti-T. gondii IgG using a commercial enzyme-linked immunosorbent assay (ELISA). The control group consisted of 192 sera samples from blood donors matched by age, gender, and residence. Chi-square tests with Yates correction were used to compare seroprevalence between WOE and the general population, and between shepherds and cheesemakers. Univariate and multivariable logistic regression analyses were performed to evaluate potential associations between T. gondii seropositivity and factors such as activity, gender, and age. Results: The overall seroprevalence was 63.5% in the WOE and 52.6% in the general population, with no statistically significant difference (p = .101). Among WOE, 52.4% of shepherds and 66.7% of cheesemakers were seropositive, with no significant difference between the two groups (p = .344). Univariate and multivariable analyses indicated neither activity, age, nor gender were significant risk factors for seropositivity in the case population. Conclusion: The study did not find a significant increased risk of T. gondii seropositivity among shepherds and cheesemakers compared to the general population. While high seroprevalence was observed in both groups, other factors unrelated to occupational exposure may be influencing the risk of T. gondii infection. More research is needed, particularly focusing on cheesemakers, to further explore potential occupational health risks related to T. gondii.
