Identification of human parechovirus‐3 in young infants within rural Victoria

We wish to provide an update on the identification of human parechovirus-type 3 (HPeV-3) in Western Victoria. Initial warnings were made in late 2013, after 20 cases were isolated in New South Wales. HPeV-3 causes a severe sepsis-like presentation in young infants. Our first three cases presented between the 6th and 19th March 2014. These cases were not initially tested for HPeV-3 but on retrospective testing were found to be positive. Two further cases presented on the 13th April and 9th May 2014 and were diagnosed during their hospital admission with HPeV-3. All five cases lived in Ballarat, 105 km west of Melbourne, Victoria. The details of the infants are presented in the Table 1 below. All had similar clinical and diagnostic features. Four were administered fluid boluses and all required close clinical monitoring. The features are comparable with those with HPeV-3 described in recent studies.1 Three infants had a rash that was non-specific and maculopapular, rather than the erythematous palmar-plantar rash that has been described with HPeV-3.2 The first four infants were treated empirically with antibiotics and aciclovir. The last case received only 48 h of antibiotics until cultures were negative. All five cases demonstrated marked tachypnoea, tachycardia, irritability and fever. Given the presentation and lack of definitive diagnosis, the first case was investigated for haemophagocytic lymphohistiocytosis (HLH). In fact, infants infected with HPeV-3 have presented with a HLH-like illness and been treated with steroid and cyclosporine.3 Human parechovirus is classified in the picornavirus family as a newly described genus. It was first isolated in Japan in 1999, and then Asia, Europe, United States and more recently, Australia.4 HPeV-1 and HPeV-2 cause mild gastrointestinal and respiratory symptoms. In contrast, HPeV-3 in infants can manifest with a more severe illness in the form of a ‘sepsis-like’ presentation, meningitis, encephalitis or myocarditis.4 Testing for HPeV-3 is available by polymerase chain reaction (on stool, blood, cerebrospinal fluid or throat swab) through a number of laboratories. Of note, the optimal sample to test is stool. Identification of the presence of HPeV-3 within Victoria highlights the need for other centres to remain vigilant. As became evident from our experience, early identification reduces length of stay and need for prolonged antibiotics. The authors would like to thank Dr David Tickell, Dr Mark Nethercote, Dr Philippa Bolton, Dr Louise Du Plessis, Dr Austen Erasmus, Dr Fiona Noble, the Ballarat Health Services Paediatric Department and Ms Georgina Papadakis of Victorian Infectious Diseases Reference Laboratory.