Further studies of neuroangiostrongyliasis (rat lungworm disease) in Australian dogs: 92 new cases (2010–2020) and results for a novel, highly sensitive qPCR assay

Abstract

The principal aim of this study was to optimize the diagnosis of canine neuroangiostrongyliasis (NA). In total, 92 cases were seen between 2010 and 2020. Dogs were aged from 7 weeks to 14 years (median 5 months), with 73/90 (81%) less than 6 months and 1.7 times as many males as females. The disease became more common over the study period. Most cases (86%) were seen between March and July. Cerebrospinal fluid (CSF) was obtained from the cisterna magna in 77 dogs, the lumbar cistern in f5, and both sites in 3. Nucleated cell counts for 84 specimens ranged from 1 to 146 150 cells μL−1 (median 4500). Percentage eosinophils varied from 0 to 98% (median 83%). When both cisternal and lumbar CSF were collected, inflammation was more severe caudally. Seventy-three CSF specimens were subjected to enzyme-linked immunosorbent assay (ELISA) testing for antibodies against A. cantonensis; 61 (84%) tested positive, titres ranging from <100 to ⩾12 800 (median 1600). Sixty-one CSF specimens were subjected to real-time quantitative polymerase chain reaction (qPCR) testing using a new protocol targeting a bioinformatically-informed repetitive genetic target; 53/61 samples (87%) tested positive, C T values ranging from 23.4 to 39.5 (median 30.0). For 57 dogs, it was possible to compare CSF ELISA serology and qPCR. ELISA and qPCR were both positive in 40 dogs, in 5 dogs the ELISA was positive while the qPCR was negative, in 9 dogs the qPCR was positive but the ELISA was negative, while in 3 dogs both the ELISA and qPCR were negative. NA is an emerging infectious disease of dogs in Sydney, Australia.

Angiostrongylosis in Animals and Humans in Europe

“…Demonstrations of the common occurrence of A. cantonensis infections in reptiles [84,85] or hedgehogs [10] serve as a proof of concept of such an approach. In Australia, disease in domestic dogs [86] and in birds [87] reflected southward expansion of A. cantonensis, and the monitoring of animal disease has an important role to play in the epidemiological surveillance of AEM risk in Europe.…”

Using cerebrospinal fluid to confirm Angiostrongylus cantonensis as the cause of canine neuroangiostrongyliasis in Australia where A. cantonensis and Angiostrongylus mackerrasae co-exist

“…The rat lungworm ( Angiostrongylus cantonensis ) is a nematode parasite of rats and gastropod molluscs known to accidently infect humans, dogs, and other animals where it causes eosinophilic meningitis and neuroangiostrongyliasis (NA) ( Wang et al., 2008 ; Lee et al., 2021 ). Alongside its definitive hosts, rats in the genus Rattus , A. cantonensis has invaded many regions of the world including Australia ( Mackerras & Sandars, 1955 ; Tokiwa et al., 2013 ; Rodpai et al., 2016 ).…”

Magnetic resonance imaging in dogs with neuroangiostrongyliasis (rat lungworm disease)

“…age of dogs at presentation in this case series compared to a large database of Australian cases (Lee et al, 2020). In companion animal practice, an MRI examination is an expensive procedure requiring a relatively long period of general anaesthesia.…”

“…A presumptive diagnosis of NA was made based on characteristic clinical signs (hind-limb paresis and/or proprioceptive ataxia, tail paresis, spinal and tail base hyperaesthesia, and urinary incontinence), eosinophilic pleocytosis in cerebrospinal fluid (CSF), and an appropriate response to therapy (prednisolone ± fenbendazole). A definitive diagnosis was made based on positive CSF serology [enzyme-linked immunosorbent assay (ELISA) antibody testing at the Parasitology Unit, Institute of Clinical Pathology and Medical Research, Westmead Hospital] and/or real-time polymerase chain reaction (qPCR) testing (Veterinary Pathology Diagnostics Service, Sydney School of Veterinary Science) using a novel, highly sensitive, bioinformatically-informed repetitive target developed at the Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA (Lee et al, 2020).…”