Equine Neurology || Miscellaneous Infections of the Central Nervous System

✍ Scribed by Furr, Martin; Reed, Stephen

• Publisher: Blackwell Publishing Ltd
• Year: 2007
• Tongue: English
• Weight: 85 KB
• Edition: 1
• Category: Article
• ISBN: 0813825199
• DOI: 10.1002/9780470376461.ch18

✦ Synopsis

CRYPTOCOCCAL MENINGITIS

Cryptococcosis is a fungal disease of humans and animals. The encapsulated yeast-like fungus is an opportunistic pathogen of debilitated or immunologically compromised individuals. Cryptococcus neoformans 1-5 is most commonly implicated, although infections with Cryptococcus albidus and Cryptococcus laurentii have been seen. 6 Cryptococcal infections in the horse usually cause rhinitis, 7,8 sinusitis, 5 or pneumonia 6 and occasionally meningitis and encephalitis. [1][2][3][4]9,10 Several reports are noted from Australia, where an association between the Eucalyptus plant (Eucalyptus camaldulensis) and the infection has been suggested. 6 In addition, an association between animals that have contact with soil contaminated with pigeon droppings is suspected. 4

Clinical Signs

Clinical signs can vary depending upon the location of the infection within the central nervous system (CNS); however, diffuse signs of encephalitis seem to predominate. Asymmetric signs were reported in one horse. 10 Depression and anorexia are often noted, as are gait stiffness, hyperesthesia, and ataxia. Sudden death was also reported in one case. 3 Variable types and degrees of cranial nerve deficit may also be seen, including blindness, nystagmus, and fixed and dilated pupils. 4 Hind limb paralysis, rectal and bladder paralysis, penile paralysis and gluteal muscle wasting have all been reported. 2,10 In many cases, the cardinal signs are normal, although mild fever and anorexia may be seen. Blindness was noted in a horse with post-orbital mass, leading to pressure necrosis of the optic nerve as the granulo-matous mass bulged into the cranial cavity displacing the left cerebral hemisphere. 5