Two cases of neuroangiostrongyliasis: A rare disease because rarely considered or rarely diagnosed?

Abstract

Aim The rat lungworm, Angiostrongylus cantonensis, is well established in eastern Australia, where it is the almost exclusive cause of human eosinophilic meningoencephalitis (EME). While neuroangiostrongyliasis can result in severe morbidity or death, its diagnosis requires a high index of clinical suspicion among medical practitioners. Prevention requires a high level of public awareness. Methods We report two cases of EME in children from Queensland and summarise all reported Australian cases from the literature. We discuss the pathogenesis of neuroangiostrongyliasis, with particular reference to the timing of prophylaxis and treatment. Results A 5‐year‐old girl developed severe headache, eosinophilic meningitis and abnormal neuroimaging following a holiday to Bali. A 10‐year‐old boy with Rubinstein‐Taybi syndrome, marked developmental delay and pica developed EME following ingestion of a snail, resulting in long‐term morbidity. From 1971 to 2018, 28 Australian cases have been reported, with acquisition restricted to Southeast Queensland and New South Wales. Ages ranged from 10 months to 45 years; most were male and most likely acquired infection from consuming unwashed lettuce or vegetables. The mortality rate was 18%; most fatalities occurred in children <1 year old. Long‐term neurological deficit was reported in 14% of cases and a full recovery in 57% of cases. Conclusions Heightened medical and public awareness of the parasite is required to prevent infection and subsequent disease. A better understanding of the efficacy of prophylactic anthelmintic following ingestion or handling of molluscs and further studies of epidemiology of this parasite will inform and facilitate public health recommendations.

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

“…Interestingly, the first report of Angiostrongylus costaricensis infection in a dog was also in a puppy (Alfaro-Alarcón et al, 2015). The disease in dogs has a shorter prodrome than in people, with clinical signs typically occurring 10 days after ingestion of infective L 3 (Jindrak and Alicata, 1970;Mason, 1987), whereas in human patients the lag phase can extend to 3 weeks (Blair et Berkhout et al, 2019;McAuliffe et al, 2019). Of human patients, children and especially infants are more likely to have severe disease, with greater morbidity and higher mortality and a tendency to suffer long-term neurologic sequelae (Morton et al, 2013;Prociv and Turner, 2018;Berkhout et al, 2019).…”

“…The disease in dogs has a shorter prodrome than in people, with clinical signs typically occurring 10 days after ingestion of infective L 3 (Jindrak and Alicata, 1970;Mason, 1987), whereas in human patients the lag phase can extend to 3 weeks (Blair et Berkhout et al, 2019;McAuliffe et al, 2019). Of human patients, children and especially infants are more likely to have severe disease, with greater morbidity and higher mortality and a tendency to suffer long-term neurologic sequelae (Morton et al, 2013;Prociv and Turner, 2018;Berkhout et al, 2019). This might be extrapolated to smaller canine patients especially puppies, as a severe disease may reflect (i) a relatively larger dose of L 3 in relation to the size of the brain, spinal cord, nerves and nerve roots and (ii) a less 'experienced' immune response.…”

“…Historically, the gold standard for the diagnosis of NA in human patients was macroscopic and microscopic examination of the brain and spinal cord at necropsy, or identification of L 3 in CSF or aqueous humour (in ocular angiostrongyliasis) (Barratt et al, 2016). Positive amplification of A. cantonensis DNA from CSF is also definitive (Blair et al, 2013;Morton et al, 2013;Qvarnstrom et al, 2016;Ming et al, 2017;Ansdell and Wattanagoon, 2018;Busse et al, 2018;Prociv and Turner, 2018;Berkhout et al, 2019;McAuliffe et al, 2019), although at some stages of infection there may be insufficient parasite DNA in CSF to permit a diagnosis by this means (Qvarnstrom et al, 2016). Detecting anti-A.…”

Need for Critical Rethinking in Clinical Approaches to Neuroangiostrongyliasis

“…Should eosinophilic meningoencephalitis be the provisional diagnosis, with early A. cantonensis infection not confidently excluded, then the working policy should be “shoot first, ask questions later.” A case could be made for treating all neurological presentations in which early NA fits among the differential diagnoses, in an appropriate epidemiological setting, urgently with anthelmintics. 2,3 Albendazole is expensive in the United States, but it can be given for only a brief course in NA, perhaps as short as 5 days. 3…”

“…2,3 Albendazole is expensive in the United States, but it can be given for only a brief course in NA, perhaps as short as 5 days. 3…”