Immunologic diseases

Selected equine cutaneous diseases for which there is strong evidence of an immunological aetiology are discussed in this section. The reactive disorders of urticaria, Culicoides hypersensitivity, erythema multiforme, drug eruptions and systemic granulomatous disease are included. The autoimmune diseases of the horse with cutaneous manifestations (pemphigus foliaceus, pemphigus vulgaris, bullous pemphigoid and cutaneous lupus erythematosus) are discussed. The clinical signs and diagnostic features of these immunologically induced equine dermatoses are defined, and the challenges in making a definitive diagnosis and managing the clinical signs are confirmed.     

Congenital diseases

In this brief section only three congenital cutaneous diseases are outlined. They include epitheliogenesis imperfecta, epidermolysis bullosa and hyperelastosis cutis. The first is an absence of epidermal structures, the second is a defect at the epidermal–dermal junction and the third is a disease of a component of the dermis. The clinical and histopathologic findings for each are described herein.     

Nodular diseases

The development of a nodule is a fairly common reaction pattern in the skin and subcutaneous tissues of the horse. In many such nodules, the inciting aetiologic agent or antigen is unknown, but in some equine cases there is significant evidence for insect bite origin. The pathogenesis of some equine nodular diseases appears to involve marked collagen degeneration which varies from hyalinization to lysis and can become mineralized. The exact role the lytic collagen has in the pathogenesis of these lesions is still unknown. Vascular changes may be present in some entities. Other nodules may be caused by or complicated by the larva of Habronema spp. The clinical or histological entities outlined in this section include the collagenolytic granuloma, axillary nodular necrosis, unilateral papular dermatosis and cutaneous habronemiasis.     

Neurologic diseases

The responses of apparently healthy newborn foals to neurologic testing differ significantly from those of adult horses. These responses and the diagnostic techniques pertinent to neurologic problems are reviewed as a basis for evaluation of the compromised neonatal foal. The more frequently encountered neurologic diseases are discussed in a problem-oriented format. These clinical problems include behavioral abnormalities, convulsions, changes in consciousness, blindness, ataxia without loss of strength, ataxia with weakness and paralysis, and the floppy foal.     

Postpartum diseases

This article includes discussions about postpartum care of the dam and postpartum disorders in the bitch such as hemorrhage, uterine prolapse, metritis, mastitis, eclampsia, and subinvolution of the placental sites.     

Protozoal diseases

The clinical and pathologic findings of and therapy for such protozoal diseases as equine protozoal myeloencephalitis, toxoplasmosis, sarcocystosis, pneumocytosis, cryptosporidiosis, giardiasis, besnoitiosis, and klossiellosis are discussed. Emphasis is placed on disorders that occur with greater frequency in North America and on emerging protozoal diseases affecting horses.     

朊粒病

由朊粒所致的疾病称朊粒病。朊粒（ｐｒｉｏｎ）是一种蛋白质,存在于许多脊椎动物的胞浆膜上,当结构异常时,就成为致病性朊粒,能引起反刍动物、人及猫科动物的神经系统疾病,统称为朊粒病（ｐｒｉｏｎｄｉｓｅａｓｅｓ）。有的是传染性,有的是遗传病,潜伏期很长,从...     

Noninfectious diseases, metabolic diseases, toxicities, and neoplastic diseases of South American camelids

Although the SAC generally are healthy and tolerant of a wide variety of management schemes, a number of noninfectious diseases have been documented to occur, affecting all body systems. Gastrointestinal diseases appear to be the most common afflictions, particularly dental diseases, indigestion, ulceration of the third compartment, and the various causes of colic, such as enteritis, peritonitis, and intestinal accidents. Diseases of the urinary system (urolithiasis, amyloidosis, and glomerulonephritis in particular), the nervous system (especially various compressive lesions of the spinal cord), and the respiratory system (such as obstructive pulmonary diseases) are not uncommon. Diseases of the cardiovascular system (other than congenital defects), hemolymphatic system, and nonsurgical diseases of the musculoskeletal system only rarely are encountered. Heat stress appears to be a very common problem in certain areas, but other metabolic diseases (ketosis, hypocalcemia, and hypothyroidism) are of minor importance. It is assumed that SAC are susceptible to most of the same toxicities that affect domestic livestock species. The best documented examples appear to be the Ericaceae family of plants (laurels, rhododendrons, and so on) and the organophosphate chlorpyrifos. Neoplasia occasionally is seen; examples include lymphosarcoma, gastric squamous cell carcinoma, and adenocarcinoma. As the longevity of these species increases because of their pet status, neoplasia can be expected to become more common. The treatment of most of these conditions is based upon extrapolation from domestic ruminants.     

多病因呼吸道病

在当今养禽业中，不但旧病复发，且常出现一些新病。其实有些新病早已存在，仅因其发病率低、临诊症状及病变不甚明显或缺乏诊断手段而被忽视。另一方面，微生物本身的基因变化使得其毒力或致病性增强，以及禽类的遗传变异改变了其本身对疾病的易感性和抵抗力也是目前养禽业中旧病复发，新病不断的一大原因。此外，环境条件或饲养管理的改变有利于微生物产生致病性。由于活禽、蛋及禽产品全球性的频繁贸易，难以将某一新病或旧病控制在某一国家或地区。从本期起，本刊对家禽的新病和一些综合征或病因不明的疾病内容加以连载，以飨读者。