Myxosporidiosis in intensively-reared Piaractus mesopotamicus: Histopathological diagnosis by means of Ziehl-Neelsen staining

Samples of different organs from intensively-reared Piaractus mesopotamicus were collected and processed using routine histological techniques in order to produce thin sections for staining with hematoxylin-eosin and with the Ziehl-Neelsen method. Through examination under an optical microscope, myxosporidians of the genera Henneguya sp. and Myxobolus sp. were identified, respectivelyin the gills and kidneys of P. mesopotamicus. Plasmodia with immature spores of Henneguya sp. were located along the secondary lamellae, with total length of 30.45±4.84µm and width of 3.52±0.33µm. Spores of Myxobolus sp. were located in the kidneys, with total length of 8.94±0.82µm and width of 5.59±0.39µm. Histopathological analysis of the gills showed plasmodia containing spores of Henneguya sp., at intralamellar and intravascular localities, at different stages of development. Spores of Myxobolus sp. were identified in the kidneys, in the peritubular region and in the interstices and glomerulus, surrounded by melanomacrophages. Focal hemorrhage was recorded in a few cases. Ziehl-Neelsen staining allowed to identify particular features of the spores and facilitated biometry and enabled classification in comparison with hematoxylin-eosin, thus demonstrating its usefulness for histopathological diagnosis of the parasitosis.

Thoracic and heart biometrics of non-anesthetized agouti (Dasyprocta primnolopha Wagler, 1831) measured on radiographic images

The agouti is a species intensively hunted throughout the Amazon and the semi-arid regions of northeastern Brazil. Considering the current trend in conservation management of wild species, the aim of this study was to determine the morphometric reference to the heart of agouti raised in captivity, based on thoracic and cardiac measurements in these animals. Thirty adult agoutis, 1 to 3 years of age, without clinical signs of cardiac disease were selected. The animals were physically restrained and radiographies in laterolateral (LL) and ventrodorsal (VD) recumbence were produced. The following measures were taken: the apicobasilar length of the heart (at the most cranial height of the Carina region to the heart apex) (AB), maximum width of the heart perpendicular to AB (CD), heart inclination angle (AIC), trachea inclination angle (AIT), distance from the right heart wall (DPTd), distance from the left heart wall (DPTe) and vertical depth of the thorax, and the ventral face of the vertebral column to the dorsal border of the sternum at the level of the trachea bifurcation (H). The ratios between AB/CD, AB/H and CD/H were also analyzed. To calculate the vertebral heart scale (VHS), the AB and CD measurements were laid over the thoracic vertebra starting at T4. Radiographic evaluation showed values consistent with those reported in small animals and some wild and exotic species. The main biometric values in the chest cavity and heart of agouti are arranged as follows: (1) The ratios between AB/H ratio and CD/H were not sensitive for identifying heart increases (p>0.05), while the ratio AB/CD was more sensitive in this identification (p<0.05); (2) AIC: 21.2±6.4º (mean between male and famale); (3) AIT for males and females: 9.93±3.23° and 8.4±3.94°; (4) DPTd and DPTe for males: 0.97±0.40cm and 0.7±0.30cm; (5) DPTd and DPTe for females: 1.12±0.42cm and 01.02±0.43cm; (6) VHS for males and females: 7.75±0.48v e 7.61±0.34v; (7) The caudal vena cava (CVC) was visualized dorsal-cranially and located right of the midline. The data obtained allowed the acquisition of the first reference values for biometry of the heart of agoutis, contributing to better understanding of cardiac morphology and identification of cardiomyopathy in these animals.