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Gestação em cadelas da raça Retriever do Labrador : alterações hematológicas, perfil de progesterona e métodos de previsão da data do parto

Publication . Dourado, Raquel Farrajota Coelho; Mateus, Luísa Maria Freire Leal; Alves, Isabel Maria Cerqueira Lopes

A gestação é um período crítico na vida reprodutiva de uma cadela, no qual ocorrem alterações fisiológicas, que devem ser do conhecimento do Médico Veterinário para que não sejam julgadas como patológicas. O intervalo entre os cruzamentos/inseminações e o parto pode ser bastante variável, pelo que a determinação precisa da data do parto é crucial para que haja um correto acompanhamento da gestação, assim como uma ótima assistência aquando do parto. Uma monitorização adequada do estro permite, não só prever o período ideal para cobrição/inseminação da cadela, como também a data do parto. Por forma a minimizar a influência da raça e do maneio a que os animais estão sujeitos, foram utilizadas neste estudo 26 cadelas da raça Retriever do Labrador [18 gestantes (G=18) e 8 não gestantes (NG=8)], pertencentes a um só canil. O primeiro objetivo deste estudo foi comparar parâmetros hematológicos e perfis das concentrações séricas de progesterona entre cadelas gestantes e não gestantes. Observou-se no grupo gestante, no período pré-parto, uma anemia normocítica, normocrómica ligeira em 45% das cadelas e uma leucocitose, devido a neutrofilia em 55% das cadelas. Verificou-se um perfil semelhante das concentrações séricas de progesterona entre fêmeas gestantes e não gestantes, portanto, o doseamento de progesterona não permite inferir se a fêmea está ou não gestante. No grupo gestante o diestro terminou entre os 63-66 dias após o pico de LH, enquanto no grupo não gestante terminou entre os 73-75 dias após o pico de LH. O segundo objetivo deste trabalho foi avaliar a precisão da previsão da data do parto utilizando como referência o dia da primeira e da última inseminação artificial (IA), o dia do pico de LH, e o dia do início do diestro citológico. O critério mais preciso para prever a data do parto foi o dia do pico de LH [86,7% (65 +/- 1 dia); 100% (65 +/- 2 dias)] comparativamente com o dia do início do diestro citológico [86,7% (57 +/- 1 dia); 86,7% (57 +/- 2 dias); 100% (57 +/- 3 dias)], sendo o mais falível a data das inseminações. O terceiro, e último, objetivo foi avaliar o impacto da monitorização do proestro/estro na performance reprodutiva. Observou-se que esta monitorização é vantajosa, uma vez que permitiu melhorar as precisões de previsão da data do parto com base na data da última IA e, ainda, diminuir o número de IA por cadela, o que é benéfico para a saúde uterina.

2018-10-04Master thesis

Open access

First description of a fatal equine infection with Halicephalobus gingivalis in Portugal : relevance for public health

Publication . Noiva, Rute; Ruivo, Pedro; Madeira de Carvalho, Luís; Fonseca, Constança; Fevereiro, Miguel; Carvalho, Paulo; Orge, Leonor; Monteiro, Madalena; Peleteiro, Maria da Concdeição

ABSTRACT - Halicephalobus gingivalisis a small saprophytic rhabditid nematode, represented only by females with a typicalrhabditoid oesophagus and one egg in the uterus, capable of infecting vertebrates. This opportunistic parasitepresent in the soil, manure and decaying humus, is thought to penetrate through previous injuries to the mouth,eyes and skin of horses and migrate to various organs. The brain is one such organ, where the females lay theireggs, leading to malacia and causing a sudden onset of neurological signs, such as anorexia, ataxia, urinaryincontinence, blindness, decreased menace and tonal reflexes, tremors and aggressiveness. The disease isinvariably fatal whenever brain lesions are present, and the diagnosis usually achieved only post-mortem. Thepresent work aims to describe the first case of infection byH. gingivalisever reported in Portugal. An 8-yearold warmblood horse presented with an 8-day history of progressive blindness involving the left eye, initiallywith normal pupillary reflexes, advancing to bilateral blindness and increasing deterioration in clinical condi-tion. After euthanasia, the animal was submitted for necropsy. Organ samples were collected and fixed in 10%neutral buffered formalin for routine histopathology. A large mass was found in the left kidney correspondingto fibrous tissue heavily infiltrated with inflammatory cells and numerous nematodes. In the brain, multiple,bilateral and asymmetrical foci of malacia containing several rhabditoid nematodes, larvae and zygotes, andhigh numbers of inflammatory cells were found. The nematodes were identified asH. gingivalis.The clinicalhistory, necropsy and histological findings presented constitute a typical case ofH. gingivalisinfection in ahorse, never previously described in Portugal to the authors’ best knowledge. Humans can be infected bycontact with contaminated manure, which makes this nematode a public health concern, especially for peopleliving and/or working in close proximity to horses.

2019-01-22Journal article

Open access

Publication . Marques, Cátia Filipa Saraiva; Belas, Adriana; Aboim, Catarina; Trigueiro, Graça; Cavaco-Silva, Patrícia; Gama, Luis; Pomba, C.

ABSTRACT - Proteus mirabilis is a major cause of urinary tract infection (UTI) in humans and companion animals. This study aimed to evaluate the antimicrobial resistance, virulence and clonal relatedness of P. mirabilis isolated from dogs, cats and humans with UTI. P. mirabilis isolated from companion animals (N = 107) and humans (N = 76) with UTI were compared by PFGE analysis after overnight Nod macro-restriction using Dice/UPGMA with a 1.5% tolerance. Strains were characterized for antimicrobial resistance by disk diffusion. Twenty-four resistance genes and four virulence genes were screened by PCR. Thirty-nine clusters (similarity > 80%) and 73 single pulse-types were detected. Nine clusters included P. mirabilis isolated from community and hospital patients, including strains with 100% similarity. A high number of clusters (43.6%, n = 17/39) included strains from companion animals and humans. Similarity between some companion animal and human strains varied between 80-100%. One strain from a dog was 100% similar to one human community-acquired P. mirabilis. One P. mirabilis from a cat was found to be 94.7% and 92.4% similar to community and hospital patient strains, respectively. P. mirabilis CMY-2-producers did not cluster all together. Nevertheless, cluster C36 included five P. mirabilis from companion animals (similarity 85.8%-95.7%), of which, four (80%) were multidrug-resistant CMY-2-producers. This study shows that companion animals and humans become infected with closely related P. mirabilis strains. The high number of clusters containing companion animals and human strains points to the zoonotic nature of P. mirabilis. These results underline the potential role of companion animals as reservoirs and in the dissemination of uropathogenic P. mirabilis to humans and vice versa.

2019-01Journal article

Open access

Mare endometrium : physiological and pathological involvement of hormones and neutrophil extracellular traps

Publication . Crisóstomo, Maria Rosa Rebordão Cordeiro Simões; Dias, Graça Maria Leitão Ferreira

Two reproductive topics in mares were addressed in this thesis. The aims of the studies were to evaluate: (i) the effect of chronic oxytocin administration to mid-luteal phase mares on luteal maintenance and its cellular and molecular mechanisms at endometrial level; (ii) the capacity of equine neutrophils to produce neutrophil extracellular traps (NETs) in vitro when stimulated with bacteria obtained from mares with endometritis, and to determine if NETs release also occurred in vivo in mares with endometritis; (iii) the in vitro effects of some NETs components on mare endometrial fibrogenic capacity and to determine if they could depend on endometrial inflammatory lesions or estrous cycle phases; and (iv) the involvement of PGF2α and PGE2 pathways in collagen deposition on mare endometrium, challenged with NETs proteases. In the first study, luteal maintenance occurred in 67% of oxytocin treated mares, which may be related to oxytocin and progesterone (PGR) receptors spatial expression in endometrium. Reduction of endometrial estrogen receptor 2 (ESR2) may be responsible for the maintenance of PGR in luminal and glandular epithelium and may attenuate ESR1 endometrial transcriptional activity. Equine neutrophils were able to release NETs in the presence of bacteria that cause mare endometritis, and might be a complementary mechanism to fight endometritis. By in vitro studies with NETs proteases, increased collagen type I (COL1) production characteristic of fibrosis was observed, although endometrial response to each NETs protease depended on estrous cycle and/or endometrial category. Also, NETs proteases were linked to fibrogenesis, by increased synthesis of PGF2a and/or PGF2a receptor transcripts and impaired PGE2 or PGE2 receptor 2 transcripts associated to increased COL1. These effects were influenced by endometrium type and estrous cycle phases. Injury induced-changes on PG mediators by NETs components may instigate PGF2α or PGE2 vias, as additional pathways in mare endometrial fibrogenesis.

2018-01-26Doctoral thesis

Open access

Toxoplasma gondii Tubulin Cofactor B plays a key role in host cell invasion and replication

Publication . Francisco, Samuel Nuno Furtado da Conceição; Narciso, Sofia Bizarro Nolasco da Silva; Leitão, José Alexandre da Costa Perdigão e Cameira

Tubulin cofactors participate in the folding, dimerization, and dissociation pathways of the tubulin dimer, being implicated in the control of tubulin proteostasis and consequently in the control of microtubule (MT) dynamics in vivo. We hypothesise that these proteins have a role in the regulation of MT cytoskeleton dynamics during Toxoplasma gondii host cell invasion. In this context, we characterized the Tubulin cofactor B (TBCB) in T. gondii. TBCB is a CAPGly domain-containing protein that together with TBCE, interact with and dissociate the tubulin dimer. The TBCB sub-cellular localization in T. gondii was studied using an in-house anti-TBCB serum. T. gondii lines overexpressing TBCB were obtained by random integration as well as TBCB conditional knockout lines by CRISPR/Cas9 system. TBCB transgenic clones were characterized by growing assays (plaque, invasion, replication and egress assays), western blot analysis and fluorescence microscopy (standard, confocal and super-resolution). TBCB showed a polarized localization, at the anterior region of the parasite, under the conoid and in close association with polar ring and subpellicular MTs. It did not present a clear co-localization with the apical complex secretory vesicles, although the interaction with rhoptries and micronemes cannot be excluded. TBCB overexpression lines showed a significant decrease in the capacity to form plaques, attributable to a proportional reduction in the capacity to invade. No differences were observed in replication and egress assays. The TgTBCB knockout line, showed a complete depletion of the protein and a viability no longer than a week. These lines showed a strong reduction in their capacity to invade the host cell and in their replication rate. In the absence of TBCB, cells have an altered axis of division resulting in abnormal division. Some parasites show the loss of the correct division axis and some parasites have four daughter cells forming inside instead of two. TBCB is a polarity marker in T. gondii and is involved in the invasion and replication processes. Its apical localization, together with TBCB mammalian partners already described (MT associated proteins) and the invasion phenotypes, suggest that TBCB can be involved in the intracellular traffic of secretory vesicles depending on MTs. Importantly, TBCB is an essential protein, constituting a good target for new control strategies.

2020-01-20Doctoral thesis

Open access