RESUMO
ABSTRACT Growing evidence suggests that parasite-infected prey is more vulnerable to predation. However, the mechanism underlying this phenomenon is obscure. In small mammals, analgesia induced by environmental stressors is a fundamental component of the defensive repertoire, promoting defensive responses. Thus, the reduced analgesia may impair the defensive ability of prey and increase their predation risk. This study aimed to determine whether coccidia infection increases the vulnerability to predation in root voles, Microtus oeconomus (Pallas, 1776), by decreased analgesia. Herein, a predator stimulus and parasitic infection were simulated in the laboratory via a two-level factorial experiment, then, the vole nociceptive responses to an aversive thermal stimulus were evaluated. Further, a field experiment was performed to determine the overwinter survival of voles with different nociceptive responses via repeated live trapping. The coccidia-infected voles demonstrated reduced predator-induced analgesia following exposure to predator odor. Meanwhile, pain-sensitive voles had lower overwinter survival than pain-inhibited voles in enclosed populations throughout the duration of the experiment. Our findings suggest that coccidia infection attenuates predator-induced analgesia, resulting in an increased vulnerability to predation.
Assuntos
Animais , Medição da Dor/veterinária , Analgesia/efeitos adversos , Doenças Parasitárias em Animais/fisiopatologia , Estações do Ano , Cadeia AlimentarRESUMO
Out of 78 adult laboratory and wild rats investigated for parasitic diseases, 19.23% were diagnosed positive for spontaneous Hymenolepis diminuta infection. Infection was more in laboratory rats (24%) than wild rats (10.71%). Sex wise distribution of H. diminuta infection was also higher male laboratory rats than females while wild rat females were found free from this tapeworm. Value of hemoglobin was significantly decreased in H. diminuta infected laboratory rats than controls. Significant increased plasma protein values in H. diminuta infected wild rats than uninfected wild rats were observed. Serum values of alkaline phosphatase, SGPT and SGOT were significantly increased in H. diminuta infected wild rats than uninfected wild rats and other groups. Tissue enzyme studies revealed that although there were alterations of different enzymes in non-target organs of H. diminuta infected rats, but only lipid peroxidation, acetylcholinesterase and catalase were altered in target organ intestine. On SEM, the segments of H. diminuta showed width from 1120 to 1160 µm while length ranged from 120 to 150 µm. Most of segments had vertical lining and raised border on its each side of circumference. On necropsy examination, intestines were found to contain 25-40 mm long and about 1 mm wide, 3-4 or more tapeworms in each rat. Relative weight of intestine was significantly increased in H. diminuta laboratory rats than controls. Histopathologically, intestinal lumina showed varying number of H. diminuta segments with serrated borders. Occasionally, scolex of tapeworm attached with intestinal mucosa was also seen. H. diminuta infection caused pressure atrophy, compressed and atrophied villi, degeneration and desquamation of lining epithelium cells and excessive mucin secretion in intestinal mucosa and lumina. Occasionally, eosinophilic cellular infiltration was also observed. High prevalence of H. diminuta infection in rats is matter of concern as zoonosis in contact human beings.(AU)
Assuntos
Animais , Ratos , Doenças Parasitárias em Animais/fisiopatologia , Himenolepíase/diagnóstico , Biomarcadores , Hymenolepis/parasitologiaRESUMO
During infectious diseases, neuroendocrine and immune networks act in concert, facilitating host response. It is known that infections cause profound immune changes, but the impact upon immunoendocrine circuits has been less studied. Disorders in the hypothalamic-pituitary-adrenal (HPA) axis were frequently observed associated with infections, and these changes often occur in parallel to alterations in the systemic cytokine network. Explanations for the infection-associated immunoendocrine disturbances include several and not mutually exclusive possibilities. Changes in cytokine levels can enhance or suppress the HPA axis, by acting at the hypothalamus-pituitary unit and/or at the adrenal glands. In situ inflammatory reactions or structural changes like vascular alterations or an enhanced extracellular matrix deposition in the endocrine microenvironment may also lead to a transient HPA dysfunction. Lastly, a microbe-related effect by means of pathogen infiltration or exploitation of the host's hormonal microenvironment may be involved as well. A better understanding of the relevance of immunoendocrine communication during infectious diseases, and how disturbances in the flux of information lead to neuroendocrine immune-related disorders will provide important insights into mechanisms underlying the disease pathology.
Assuntos
Doenças Transmissíveis/fisiopatologia , Citocinas/fisiologia , Hormônios/fisiologia , Sistema Hipotálamo-Hipofisário/fisiopatologia , Sistema Hipófise-Suprarrenal/fisiopatologia , Animais , Bovinos , Desidroepiandrosterona/fisiologia , Proteínas da Matriz Extracelular/fisiologia , Feminino , Glucocorticoides/fisiologia , Interações Hospedeiro-Parasita/imunologia , Interações Hospedeiro-Parasita/fisiologia , Interações Hospedeiro-Patógeno/fisiologia , Humanos , Inflamação/imunologia , Inflamação/fisiopatologia , Masculino , Camundongos , Modelos Imunológicos , Papio , Doenças Parasitárias em Animais/imunologia , Doenças Parasitárias em Animais/fisiopatologia , Estresse Fisiológico/imunologia , Estresse Fisiológico/fisiologia , Células Th1/imunologia , Células Th2/imunologiaRESUMO
Relata-se o primeiro caso de infecção de perus, Meleagris gallopavo, por Cheilospirura hamulosa no Brasil, com base no achado de três espécimes fêmeas de C. hamulosa, inseridos na submucosa da moela de um peru, retirado de um lote de 15 aves, provenientes de criadouros domésticos no estado de Minas Gerais. A ocorrência foi de 6,7 por cento. A ave parasitada não apresentava sinais clínicos. As lesões microscópicas da moela eram severas, caracterizando-se por intensos processos inflamatórios crônicos e difusos, com infiltrados mistos de granulócitos, estendendo-se à mucosa e às camadas musculares. Nessa área, foram observados fragmentos dos parasitos e perfuração da mucosa, com destruição das camadas musculares.
Assuntos
Doenças Parasitárias em Animais/epidemiologia , Doenças Parasitárias em Animais/fisiopatologia , Perus/anatomia & histologia , Perus/parasitologia , BrasilRESUMO
Relata-se o primeiro caso de infecção de perus, Meleagris gallopavo, por Cheilospirura hamulosa no Brasil, com base no achado de três espécimes fêmeas de C. hamulosa, inseridos na submucosa da moela de um peru, retirado de um lote de 15 aves, provenientes de criadouros domésticos no estado de Minas Gerais. A ocorrência foi de 6,7%. A ave parasitada não apresentava sinais clínicos. As lesões microscópicas da moela eram severas, caracterizando-se por intensos processos inflamatórios crônicos e difusos, com infiltrados mistos de granulócitos, estendendo-se à mucosa e às camadas musculares. Nessa área, foram observados fragmentos dos parasitos e perfuração da mucosa, com destruição das camadas musculares.(AU)