Noiva Rute, Ruivo Pedro, de Carvalho Luís Madeira, Fonseca Constança, Fevereiro Miguel, Carvalho Paulo, Orge Leonor, Monteiro Madalena, Peleteiro Maria Conceição
CIISA, Interdisciplinary Centre of Research in Animal Health, Faculdade de Medicina Veterinária, Universidade de Lisboa, Av. da Universidade Técnica, Lisbon, Portugal.
Integrated Masters Course of Veterinary Medicine, Faculdade de Medicina Veterinária, Universidade de Lisboa, Av. da Universidade Técnica, Lisbon, Portugal.
Vet Med Sci. 2019 May;5(2):222-229. doi: 10.1002/vms3.142. Epub 2019 Jan 22.
Halicephalobus gingivalis is a small saprophytic rhabditid nematode, represented only by females with a typical rhabditoid oesophagus and one egg in the uterus, capable of infecting vertebrates. This opportunistic parasite present 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 their eggs, leading to malacia and causing a sudden onset of neurological signs, such as anorexia, ataxia, urinary incontinence, blindness, decreased menace and tonal reflexes, tremors and aggressiveness. The disease is invariably fatal whenever brain lesions are present, and the diagnosis usually achieved only post-mortem. The present work aims to describe the first case of infection by H. gingivalis ever reported in Portugal. An 8-year old warmblood horse presented with an 8-day history of progressive blindness involving the left eye, initially with normal pupillary reflexes, advancing to bilateral blindness and increasing deterioration in clinical condition. 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 corresponding to 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, and high numbers of inflammatory cells were found. The nematodes were identified as H. gingivalis. The clinical history, necropsy and histological findings presented constitute a typical case of H. gingivalis infection in a horse, never previously described in Portugal to the authors' best knowledge. Humans can be infected by contact with contaminated manure, which makes this nematode a public health concern, especially for people living and/or working in close proximity to horses.
牙龈哈氏线虫是一种小型腐生性小杆线虫，仅以雌性形式存在，具有典型的小杆状食管，子宫内有一个卵，能够感染脊椎动物。这种机会性寄生虫存在于土壤、粪便和腐烂的腐殖质中，被认为是通过先前马的口腔、眼睛和皮肤的损伤处侵入，并迁移到各个器官。大脑就是这样一个器官，雌性线虫在其中产卵，导致软化，并引起神经症状的突然发作，如厌食、共济失调、尿失禁、失明、威胁反射和音调反射减弱、震颤和攻击性。只要存在脑部病变，该病必然致命，通常只有在死后才能确诊。本研究旨在描述葡萄牙首次报道的牙龈哈氏线虫感染病例。一匹8岁的温血马有8天渐进性失明病史，最初左眼瞳孔反射正常，后来发展为双眼失明，临床状况不断恶化。安乐死后，对该动物进行了尸检。采集器官样本并固定在10%中性缓冲福尔马林中用于常规组织病理学检查。在左肾发现一个大肿块，对应于大量炎性细胞浸润的纤维组织和大量线虫。在大脑中，发现多个双侧不对称的软化灶，含有几条小杆状线虫、幼虫和受精卵，以及大量炎性细胞。这些线虫被鉴定为牙龈哈氏线虫。所呈现的临床病史、尸检和组织学结果构成了马牙龈哈氏线虫感染的典型病例，据作者所知，此前在葡萄牙从未有过描述。人类可通过接触受污染的粪便而感染，这使得这种线虫成为公共卫生问题，尤其是对于生活和/或工作在马附近的人。
