Laboratório de Pesquisa Clínica em Dermatozoonoses em Animais Domésticos, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Av. Brasil, 4365, Rio de Janeiro, RJ, 21040-360, Brazil.
Instituto Carlos Chagas, Fundação Oswaldo Cruz, Rua Professor Algacyr Munhoz Mader, 3775, Curitiba, PR, 81350-010, Brazil.
Parasit Vectors. 2021 Jun 12;14(1):321. doi: 10.1186/s13071-021-04813-3.
Zoonotic visceral leishmaniasis is caused by the protozoan Leishmania infantum and is highly lethal in humans and dogs if left untreated. The frequency of this parasite and associated histological changes in the pancreas of dogs are poorly studied. Therefore, the objectives of this study were to evaluate the frequency of detection and load of amastigotes in the pancreas of L. infantum-seropositive dogs and to identify the clinical signs and histological changes associated with parasitism of this organ.
One hundred forty-three dogs from an endemic area in Brazil that tested seropositive for L. infantum were studied. The dogs were clinically examined, killed, and necropsied between 2013 and 2014. One fragment of the pancreas was randomly collected for histopathology and immunohistochemistry, and spleen and bone marrow were collected for culture.
Leishmania amastigotes were detected in the pancreas of 22 dogs (15.4%) by immunohistochemistry, all exhibiting L. infantum parasitism in the spleen and/or bone marrow. Poor body condition and cachexia were only associated with infection of the pancreas with Leishmania spp. (p = 0.021) and were found in 40.9% of dogs with pancreatic infection. Anorexia, vomiting, and/or diarrhea were observed in 9.2% of dogs with pancreatitis. The median parasite load in the pancreas was 1.4 infected macrophages/mm. Pancreatic histological changes and their frequencies were: granulomatous pancreatitis (28.0%), lymphoplasmacytic pancreatitis (23.8%), acinar cell degeneration (6.3%), fibrosis (5.6%), hemorrhage (2.1%), eosinophilic pancreatitis (0.7%), suppurative pancreatitis (0.7%), and necrosis (0.7%).
The present results demonstrate that L. infantum is one of the etiological agents of chronic pancreatitis in dogs; however, the frequency of detection and parasite load are low in this organ. The lack of an association of poor body condition and cachexia with pancreatitis and the low frequency of clinical signs commonly associated with pancreatitis suggest that a significant portion of the organ is not affected by this parasite. On the other hand, the association of poor body condition and cachexia with concomitant infection of the pancreas, spleen, and/or bone marrow with this parasite suggests that these manifestations are the result of a more advanced stage of canine visceral leishmaniasis.
人兽共患内脏利什曼病由原生动物利什曼原虫引起，如果不治疗，对人和狗具有高度致命性。这种寄生虫在狗胰腺中的频率及其相关组织学变化研究甚少。因此，本研究的目的是评估利什曼原虫血清阳性犬胰腺中利什曼原虫的检测频率和负荷，并确定与该器官寄生相关的临床症状和组织学变化。
本研究共纳入 143 只来自巴西一个流行地区的利什曼原虫血清阳性犬。这些狗在 2013 年至 2014 年间进行了临床检查、处死和剖检。随机采集胰腺的一个片段进行组织病理学和免疫组织化学检查，采集脾脏和骨髓进行培养。
通过免疫组织化学，在 22 只（15.4%）狗的胰腺中检测到利什曼原虫无鞭毛体，所有这些狗的脾脏和/或骨髓中均存在利什曼原虫寄生。身体状况差和恶病质仅与利什曼属感染胰腺有关（p=0.021），40.9%的胰腺感染狗有这种情况。厌食、呕吐和/或腹泻见于 9.2%的胰腺炎狗。胰腺内寄生虫负荷中位数为 1.4 个感染巨噬细胞/mm。胰腺组织学变化及其频率如下：肉芽肿性胰腺炎（28.0%）、淋巴浆细胞性胰腺炎（23.8%）、腺泡细胞变性（6.3%）、纤维化（5.6%）、出血（2.1%）、嗜酸性粒细胞性胰腺炎（0.7%）、化脓性胰腺炎（0.7%）和坏死（0.7%）。
本研究结果表明，利什曼原虫是犬慢性胰腺炎的病因之一，但在该器官中检测到的寄生虫频率和负荷较低。身体状况差和恶病质与胰腺炎无关联，与胰腺炎相关的临床症状频率较低，这表明大部分胰腺组织不受这种寄生虫的影响。另一方面，身体状况差和恶病质与胰腺、脾脏和/或骨髓同时感染这种寄生虫有关，这表明这些表现是犬内脏利什曼病更晚期的结果。
