Parastrongylus (= Angiostrongylus) cantonensis is a parasitic nematode of Norway rats throughout tropical regions. This parasite is neurotropic and causes disease and death in humans and other mammals. We report the first identification of P. cantonensis as the cause of a debilitating neurologic disease in a captive primate in Florida.

Of the three immunoglobulin G (IgG) isotypes described to occur in camelids, IgG2 and IgG3 are distinct in that they do not incorporate light chains. These heavy-chain antibodies (HCAbs) constitute approximately 50% of the IgG in llama serum and as much as 75% of the IgG in camel serum. We have produced isotype-specific mouse monoclonal antibodies (MAbs) in order to investigate the roles of HCAbs in camelid immunity. Seventeen stable hybridomas were cloned, and three MAbs that were specific for epitopes on the ␥ chains of llama IgG1, IgG2, or IgG3 were characterized in detail. Affinity chromatography revealed that each MAb bound its isotype in solution in llama serum. The antibodies bound to the corresponding alpaca IgGs, to guanaco IgG1 and IgG2, and to camel IgG1. Interestingly, anti-IgG2 MAbs bound three heavy-chain species in llama serum, confirming the presence of three IgG2 subisotypes. Two IgG2 subisotypes were detected in alpaca and guanaco sera. The MAbs detected llama serum IgGs when they were bound to antigen in enzyme-linked immunosorbent assays and were used to discern among isotypes induced during infection with a parasitic nematode. Diseased animals, infected with Parelaphostrongylus tenuis, did not produce antigen-specific HCAbs; rather, they produced the conventional isotype, IgG1, exclusively. Our data document the utility of these MAbs in functional and physiologic investigations of the immune systems of New World camelids.

Abstract. Parasitic granulomatous eosinophilic inflammation was observed in the central nervous system (CNS) of a 6-month-old Arabian colt from New York state. Inflammation was associated with eggs, larvae, and adult nematodes in the cerebellum. Nematodes had histological characteristics of the superfamily Metastrongyloidea. The presence of dorsal-spined larvae in the CNS was further indicative of infection with a nematode in the family Protostrongylidae. Infections were most compatible with Parelaphostrongylus tenuis but specific diagnosis was not possible. This is the first definitive report of a protostrongylid nematode infection in a horse.Key words: CNS; dorsal-spined larvae; histopathology; horses; Metastrongyloidea; nematodes; parasitic encephalomyelitis; Parelaphostrongylus tenuis.Parasitic migratory encephalomyelitis is a rare but important cause of neurologic disease in horses. Metazoan parasites identified from the equine central nervous system (CNS) include nematodes (Strongylus vulgaris, S. equinus, Angiostrongylus cantonensis, Halicephalobus gingivalis, Setaria spp., and Draschia megastoma) and fly larvae (Hypoderma spp.). 9 We identified parasitic nematodes in the CNS of a young horse in New York state. Nematode morphology and its occupation of the CNS were most compatible with the meningeal worm, Parelaphostrongylus tenuis. The northeastern USA has a high density of white-tailed deer (Odocoileus virginianus) that have a high prevalence of P. tenuis infection. This neurotropic nematode causes a debilitating neurologic disease in cervids, 1,6 ovids, 1 bovids, 1,5,12 and camelids.1 Recently, Van Biervliet et al. identified a Metastrongyloidea nematode in the CNS of a horse, 11 but specific identification of the parasite was not possible. Here we present the first definitive report of protostrongylid nematodes in the CNS of a horse.A 6-month-old male Arabian horse had acute onset of an abnormal gait and held its head to the right. There was no history of pyrexia or systemic illness. The colt was born in New York state and had not traveled to other states. Clinical signs persisted following treatment with dexamethasone, and the horse was referred to the Cornell University Hospital for Animals. Clinical examination revealed marked spastic tetraparesis and ataxia in all four limbs. The head and neck were held to the right side. A C1 to C5 lesion was suspected. Cerebrospinal fluid contained mildly increased protein (116 mg/dl, normal range 5-100 mg/dl) and 1200 cells/ml (58% lymphocytes, 40% neutrophils, 2% macrophages, and a few eosinophils and erythrocytes). Cervical radiographs were suspicious for subluxation at the atlanto-occipital joint. Computed tomography (CT) examinations were normal except for a mild atlantooccipital joint subluxation, and a light weight cast was applied as treatment for the subluxation. The foal was unable to stand on recovery from anesthesia for the CT scan and struggled violently to attempt to stand. The patient was humanely euthanized and a necropsy was performed.Necropsy e...

Parelaphostrongylus tenuis is a neurotropic nematode common in white-tailed deer (Odocoileus virginianus) of eastern North America. This parasite is the causative agent of a debilitating neurologic disease in atypical hosts, including domestic livestock. In order to identify proteins of potential significance in the host-parasite relationship, a cDNA library was produced from adult P. tenuis mRNA. Screening the library with antisera from infected red deer (Cervus elaphus elaphus) and immunized AO strain rats, we identified clones with sequence similarities to aspartyl protease inhibitors from several parasitic nematodes. Antibody that was generated against this recombinant protein of P. tenuis (Pt-API-1) detected the native protein in E/S products, in muscle and gonad, and on the surface of the cuticle of adult male and female P. tenuis. The native protein was detected in internal structures of first-stage (L1) and third-stage (L3) larvae. Reverse transcription-PCR confirmed expression of Pt-api-1 in L1, L3, and adult male and female worms. Expression of Pt-API-1 throughout the life cycle of P. tenuis suggests an essential function. Antibodies specific for recombinant Pt-API-1 were detected by enzyme-linked immunosorbent assay in sera from 12 red deer experimentally infected with P. tenuis. Antibodies were detected within 28 to 56 days postinfection. Responses were sustained or biphasic in animals with patent infections, consistent with expression of Pt-API-1 by L1. Our results are compatible with findings in other parasitic nematodes showing that aspartyl protease inhibitors are highly immunogenic.