Epidemiologia e diagnóstico da besnoitiose bovina em Portugal

Tese de Doutoramento em Ciências Veterinárias. Especialidade de Sanidade AnimalA besnoitiose bovina, causada por Besnoitia besnoiti, é uma doença reemergente na Europa. Neste trabalho, após revisão do conhecimento sobre a epidemiologia, patogenia e diagnóstico, dedicou-se especial atenção ao ciclo de vida e vias de transmissão deste agente. Desenvolveu-se uma técnica serológica de aglutinação direta (B-MAT), com elevada sensibilidade (96,9%) e especificidade (99,7%), validada num rastreio nacional para determinar a prevalência e distribuição geográfica de B. besnoiti. Neste rastreio, envolvendo 391 explorações em 83 concelhos, observou-se uma verdadeira prevalência de explorações infetadas de 5,1% e uma prevalência média intraexploração de 33,0% (0,7-72,4%). Por varredura espacial detetou-se um cluster no Alentejo, o que está de acordo com as observações clínicas históricas. Um inquérito nacional aos médicos veterinários de campo revelou que apenas 17,5% tinham experiência clínica da doença, maioritariamente no Alentejo. Finalmente, num rastreio serológico de 1297 animais pertencentes a outras espécies domésticas e silváticas pela técnica B-MAT, não se detetou a presença de anticorpos anti-B. besnoiti. Considerando a importância económica da doença, a sua divulgação junto dos médicos veterinários e criadores bem como a investigação da sua epidemiologia são fundamentais para apoiar o sector pecuário nacional, sobretudo no Alentejo onde se encontra a maior prevalência serológica e de casos clínicos.ABSTRACT - Epidemiology and diagnosis of bovine besnoitiosis in Portugal - Bovine besnoitiosis, caused by Besnoitia besnoiti, is a re-emergent disease in Europe. In this work, after reviewing the present knowledge on the epidemiology, pathogeny and diagnosis, special attention was devoted to the studies on the life cycle and transmission of this parasite. A direct agglutination serological technique (B-MAT) with a high sensitivity (96.9%) and specificity (99.7%) was developed and validated in a national survey to determine the prevalence and geographic distribution of B. besnoiti. The survey covered 391 herds in 83 municipalities. A true herd prevalence of 5.1% and a mean within-herd prevalence of 33.0% (0.7-72.4%) were estimated. Spatial scan statistics identified one cluster in the region Alentejo, which is in agreement with historical clinical data. A national inquiry to veterinary field practitioners showed that only 17.5% had clinical experience of besnoitiosis, the majority in Alentejo. Finally, no anti-B. besnoiti antibodies were detected in a B-MAT serological screening of 1297 animals belonging to other domestic and wildlife species. Considering the economic importance of the disease, the dissemination of information among veterinary practitioners and cattle producers as well as extended research on its epidemiology are essential to support the national livestock sector, especially in Alentejo, where the highest serological and clinical prevalence are found

Fatal toxoplasmosis in a captive squirrel monkey (Saimiri boliviensis) in Portugal

8 páginas, 1 tabla, 3 figuras.New World monkeys are especially vulnerable to develop severe clinical manifestations and succumb to acute toxoplasmosis. This study aimed to describe the histopathological findings and genotypic characterization of the Toxoplasma gondii strain involved in a lethal case occurring in a zoo-housed black-capped squirrel monkey (Saimiri boliviensis) in Portugal. Cyst-like structures suggestive of Sarcocystidae parasites and acute injuries in liver and brain were observed by light microscopy examination. By immunohistochemistry, calprotectin, T. gondii antigen and Iba1 antigen had a positive signaling in lung, liver and brain tissues. Toxoplasma gondii B1, ITS1 and 529 repetitive element fragments amplifications together with the genotyping of 13 microsatellite markers confirmed a systemic T. gondii infection linked to a non-clonal type II strain. This description is consistent to the majority T. gondii strains circulating in Europe.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. LMO-M, and RC-B are part of the TOXOSOURCES consortium supported by the funding from the European Union’s Horizon 2020 Research and Innovation Programme under the Grant Agreement No 773830: One Health European Joint Programme.Peer reviewe

Seroprevalence and Risk Factors for Toxoplasma gondii and Neospora caninum in Cattle in Portugal

Neospora caninum has a worldwide economic impact as an important cause of abortion in cattle, while Toxoplasma gondii, another abortifacient pathogen, is globally a major foodborne zoonotic threat. The study aimed to evaluate the seroprevalence and risk factors for the two parasites in cattle in Portugal. A total of 612 sera from 35 farms were tested by an in-house p30 ELISA for T. gondii and p38 ELISA for N. caninum. T. gondii positive and suspicious sera were confirmed by p30 Western blot or IFAT. T. gondii and N. caninum animal seroprevalence was 9.2% (95%CI 7.1–11.7) and 17.2% (95% CI 14.4–20.4) and herd seroprevalence was 51.4% (95% CI 35.6–67.0) and 68.6% (95% CI 52.0–81.5), respectively. At the univariable level, climate area and precipitation of wettest month, driest month, driest quarter, and warmest quarter were significant predictors of seropositivity for both. N. caninum seropositivity was more likely in the region Norte, densely populated areas, and intensive production, and the probability of T. gondii seropositivity decreased with herd size. Results confirm the need to consider neosporosis in the differential diagnosis of cattle reproductive disorders in Portugal and may be valuable to inform source attribution models for human toxoplasmosis

Epidemiological and genetic characterization of Toxoplasma gondii in urban pigeons from the area of Lisbon (Portugal)

Circumstantial evidence suggests that birds may be a good indicator of soil contamination, since they feed from the ground. Therefore a study was conducted to assess the prevalence of Toxoplasma gondii in urban pigeons (Columba livia) from different areas of the city of Lisbon and to genetically characterize T. gondii strains isolated from infected animals, in order to assess circulating genotypes. Sera from 695 pigeons captured at 33 different localities of the city of Lisbon were assayed by the direct agglutination test (DAT) showing a 4.6% prevalence. One third of flocks sampled revealed to be infected with T. gondii, with prevalence ranging between 5% and 62.5%. T. gondii DNA could be characterized directly from brain tissue from 12 of 23 seropositive pigeons. Microsatellite typing revealed that 9 strains belonged to type II, 2 were type III and one was type I. No recombinant or atypical genotypes were found. Attempts to recover viable T. gondii strains through bioassay in mice resulted in the isolation of 9 strains.Câmara Municipal de Lisboa (Municipality of Lisbon

Survey on the prevalence of Dermanyssus gallinae in commercial laying farms in Portugal

Dermanyssus gallinae, also known as the poultry red mite (PRM), is a blood-feeding ectoparasite of poultry and sylvatic birds. This mite is endemic in many parts of the globe and poses a threat to the egg industry, while compromising the health and welfare of hens, both directly and as a vector of diseases. In addition, people attacked by D. gallinae may develop gamasoidosis. Despite the high prevalence in several European countries, epidemiological information on D. gallinae in Portugal is scarce. This study aimed to assess the prevalence and infestation levels in laying farms in Portugal and evaluate the perception and attitudes of producers regarding D. gallinae. A survey was performed between August 2016 – November 2017, which included 24 farms in the NUTS2 regions Centro and Norte. Mites were sampled with corrugated cardboard traps and the perception and attitudes of farmers regarding the PRM were evaluated with the European COREMI questionnaire prepared by WG 1 of the COST action FA1404. D. gallinae was detected in 95.8% of farms (95% CI: 79.8–99.3%). The average number of trapped mites among farms was 5200 ± 16,522, with a median of 359 mites (interquartile range = 46–3135). Results from the questionnaire show that insufficient monitoring, under-detection and late and suboptimal treatment may contribute to the maintenance of significant infestation levels. The present data highlight the need for adequate monitoring of D. gallinae, timely action and effective treatment in order to improve poultry productivity and ensure human and animal health and welfare. RESEARCH HIGHLIGHTS A survey on the prevalence of D. gallinae in Portuguese layer farms is presented The perceived importance of D. gallinae was assessed with a questionnaire D. gallinae was detected in 95.8% of farms The results emphasize the need for adequate monitoring and treatment optimization.</p

Assessing the failure in transfer of passive immunity in beef calves: two case reports

Introduction: Failure in Transfer of Passive Immunity (FTPI) is a condition that occurs frequently in the bovine species when inadequate ingestion or absorption of enough good-quality colostrum takes place. In bovine kept in extensive conditions, FTPI diagnosis is usually made by complete physical examination, with not enough time for laboratory analysis, and treatment is based on the administration of colostrum replacement products or transfusion. Objectives: To evaluate the transfer of passive immunity in meat calves kept in extensive conditions. Methods: We hereby describe two case reports of calves presenting clinical signs compatible with FTPI and their biochemical analysis, including IgG determination by an ELISA test. Results: The results indicated that both calves presented a very low serum IgG concentration (calf 1: 0.7mg/ml and calf 2: 1mg/ml), confirming FTPI. The animals were treated with a plasma transfusion from a crossbreed cow. At 24 hours after the plasma transfusion, serum IgG concentration raised slightly on both animals, but after 48 hours serum IgG reduced to a concentration similar to the pre-transfusion values. Conclusions: We conclude that plasma transfusion can be an effective treatment for FTPI in clinical cases in extensive conditions but it has to be monitored assuring that serum IgG concentration reaches normal values. Immunological status of donors should be assessed before plasma collection and transfer.info:eu-repo/semantics/publishedVersio

Avaliação da falha de transferência de imunidade passiva em vitelos de carne: dois casos clínicos

Introduction: Failure in Transfer of Passive Immunity (FTPI) is a condition that occurs frequently in the bovine species when inadequate ingestion or absorption of enough good-quality colostrum takes place. In bovine kept in extensive conditions, FTPI diagnosis is usually made by complete physical examination, with not enough time for laboratory analysis, and treatment is based on the administration of colostrum replacement products or transfusion. Objectives: To evaluate the transfer of passive immunity in meat calves kept in extensive conditions. Methods: We hereby describe two case reports of calves presenting clinical signs compatible with FTPI and their biochemical analysis, including IgG determination by an ELISA test. Results: The results indicated that both calves presented a very low serum IgG concentration (calf 1: 0.7mg/ml and calf 2: 1mg/ml), confirming FTPI. The animals were treated with a plasma transfusion from a crossbreed cow. At 24 hours after the plasma transfusion, serum IgG concentration raised slightly on both animals, but after 48 hours serum IgG reduced to a concentration similar to the pre-transfusion values. Conclusions: We conclude that plasma transfusion can be an effective treatment for FTPI in clinical cases in extensive conditions but it has to be monitored assuring that serum IgG concentration reaches normal values. Immunological status of donors should be assessed before plasma collection and transfer.Introdução: A Falha de Transferência de Imunidade Passiva (FTIP) é uma condição que ocorre frequentemente na espécie bovina após ingestão ou absorção inadequada de quantidades suficientes de colostro de qualidade adequada. Em bovinos mantidos em extensivo, o diagnóstico é habitualmente realizado através de um exame clínico completo, não existindo tempo suficiente para uma análise laboratorial, e o tratamento é baseado na administração de substitutos de colostro ou transfusão. Objetivos: Avaliar a transferência de imunidade passiva em vitelos de carne em cultivo extensivo. Métodos: No presente trabalho descrevem-se dois casos clínicos de vitelos com sinais clínicos compatíveis com FTIP, assim como a sua análise bioquímica, incluindo determinação de igg através de um teste ELISA. Resultados: Ambos os vitelos apresentavam uma concentração sérica muito baixa de igg (vitelo 1: 0.7mg/ml e vitelo 2: 1mg/ml), confirmando a FTIP. Os animais foram tratados com uma transfusão de plasma de uma vaca cruzada. Após 24 horas da transfusão de plasma, a concentração de igg aumentou ligeiramente em ambos os animais, mas após 48 horas da transfusão a concentração reduziu para valores semelhantes aos verificados antes do tratamento. Conclusões: A transfusão de plasma pode ser um tratamento eficaz para a FTIP de casos clínicos em condições de extensivo, mas esta terá de ser monitorizada garantindo que a concentração sérica de igg atinge valores adequados. O estado imunitário das dadoras deve ser avaliado antes da colheita e transfusão de plasma.Introducción: El Fallo de Transferencia de Inmunidad Pasiva (FTIP) es una condición que ocurre frecuentemente en la especie bovina, después de la inadecuada ingestión o absorción de calostro de calidad adecuada. En bovinos mantenidos en extensivo, el diagnóstico de FTIP es frecuentemente realizado con un examen físico completo, sin tiempo suficiente para realizar un análisis de laboratorio, y el tratamiento se basa en la administración de sustitutos de calostro o transfusión. Objetivos: Evaluar la transferencia de inmunidad pasiva en terneros de carne. Métodos: En este trabajo se describen dos casos clínicos de becerros con signos clínicos compatibles con FTIP y sus análisis bioquímicos, incluyendo determinación de IgG con un test ELISA. Resultados: Los resultados indicaron que los dos becerros presentaban una concentración sérica muy baja de IgG (vitelo 1: 0.7mg/mL y vitelo 2: 1mg/mL), confirmando FTIP. Los animales fueron tratados con una transfusión de plasma de una vaca cruzada. Tras 24 horas de la transfusión de plasma, la concentración de IgG incrementó ligeramente en ambos animales, pero tras 48 horas de la transfusión la concentración se redujo para valores semejantes a los verificados antes del tratamiento. Conclusiones: La transfusión de plasma puede ser un tratamiento eficaz para la FTIP de casos clínicos en condiciones de extensivo, pero tendrá de ser monitorizada garantizando que la concentración sérica de IgG alcanza valores adecuados. El estadio inmunitario de las donantes debe ser evaluado antes de la recogida y transfusión de plasma

Isolation and molecular characterization of Toxoplasma gondii isolated from pigeons and stray cats in Lisbon, Portugal

Cats and pigeons are important factors in the epidemiology of Toxoplasma gondii as felids are the only definitive hosts that can excrete environmentally resistant oocysts, and pigeons share the same places of cats and humans constituting a good model and indicator of the ground field contamination. We aimed to study the virulence and genotypes of T. gondii isolated from pigeons and stray cats in Lisbon, Portugal. Fresh samples of brain from 41 pigeons and 164 cats revealing antibodies to T. gondii were inoculated in mice. Three isolates (one isolated from a cat and two isolated from pigeons) were virulent in the mouse model. Sag2-based genotyping of T. gondii was achieved in 70.7% (29/41) of samples isolated from pigeons (26 samples were type II, two were type III, and one strain was type I). From the cat brain samples, 50% (82/164) yielded Sag2 positive results, where 72 belonged to genotype II and 10 were no type III (it was not possible to discriminate between type I and II). Further genotyping was obtained by multiplex PCR of 5 microsatellites (TUB2, TgM-A, W35, B17, B18), allowing the identification of two recombinant strains that had been previously identified as type II by Sag2 amplification (one isolated from cat brain and the other from pigeon brain). This is the first evidence of recombinant strains circulating in Portugal and the first report of T. gondii genotyping from cats in this country. This study also highlights the importance of environmental contamination in the synanthropic cycle constituting a potential source of human infection.FCT e Câmara Municipal de Lisbo

In vitro isolation and seroprevalence of Toxoplasma gondii in stray cats and pigeons in Lisbon, Portugal

Oral contamination with Toxoplasma gondii oocysts shed by cats into the environment has been linked to severe outbreaks of human toxoplasmosis. Pigeons (Columba livia) are highly susceptible to oral infection with oocysts and indirectly indicate soil contamination, since they feed from the ground. A seroprevalence study was performed on cats and pigeons captured in the city of Lisbon. Serum samples collected from 1507 pigeons captured at 64 feeding sites and 423 stray cats were screened for antibodies anti-T. gondii using a commercial direct agglutination test. Seroprevalence in pigeons was 2.6% (39/1507) (95% CI: 1.9–3.5%) and 37.5% (24/64) of pigeon flocks sampled showed to be infected with T. gondii. The proportion of infected pigeons within seropositive flocks ranged between 4.8% and 21.1%. Among cats, seroprevalence was 44.2% (187/423) (95% CI: 39.5–49.1%). Isolation of T. gondii from animal tissues was attempted by in vitro assay. Inoculation of brain homogenates from 20 pigeons and 56 cats into Vero cell cultures allowed isolation of T. gondii from 13 pigeons (65%) and 15 cats (26.8%). Inoculation of muscle homogenates (heart and limbs) prepared by acid-peptic digestion from a subset of 15 cats resulted in the recovery of T. gondii from 10 cats (66.7%).FC

Mathematical modelling of transmission: A systematic review.

Toxoplasma gondii is a ubiquitous protozoan parasite that can infect virtually all warm-blooded animals. It is the causative agent of toxoplasmosis, a significant public health issue worldwide. Mathematical models are useful to study the transmission dynamics of T. gondii infection in different settings, and may be used to compare the effectiveness of prevention measures