Identification and Characterization of a New Orthoreovirus from Patients with Acute Respiratory Infections

et al. (2008) Identification and Characterization of a New Orthoreovirus from Patients with Acute Respiratory Infections. PLoS ONE 3(11): e3803. doi:10.1371/journal.pone.0003803 Identification and Characterization of a New Orthoreovirus from Patients with Acute Respiratory Infections Kaw Bing Chua 0 Kenny Voon 0 Gary Crameri 0 Hui Siu Tan 0 Juliana Rosli 0 Jennifer A. McEachern 0 Sivagami Suluraju 0 Meng Yu 0 Lin-Fa Wang 0 Olivier Schwartz, Institut Pasteur, France 0 1 National Public Health Laboratory , Sg. Buloh, Selangor , Malaysia , 2 International Medical University , Bukit Jalil, Kuala Lumpur, Malaysia, 3 CSIRO Livestock Industries , Australian Animal Health Laboratory and Australian Biosecurity Cooperative Research Center for Emerging Infectious Diseases , Geelong , Australia , 4 Klinik Kesihatan Kampar, Jalan Degong, Perak , Malaysia First discovered in the early 1950s, reoviruses (respiratory enteric orphan viruses) were not associated with any known disease, and hence named orphan viruses. Recently, our group reported the isolation of the Melaka virus from a patient with acute respiratory disease and provided data suggesting that this new orthoreovirus is capable of human-to-human transmission and is probably of bat origin. Here we report yet another Melaka-like reovirus (named Kampar virus) isolated from the throat swab of a 54 year old male patient in Kampar, Perak, Malaysia who was suffering from high fever, acute respiratory disease and vomiting at the time of virus isolation. Serological studies indicated that Kampar virus was transmitted from the index case to at least one other individual and caused respiratory disease in the contact case. Sequence analysis of the four small class genome segments indicated that Kampar and Melaka viruses are closely related. This was confirmed by virus neutralization assay, showing an effective two-way cross neutralization, i.e., the serum against one virus was able to neutralize the other. Although the exact origin of Kampar virus is unknown, epidemiological tracing revealed that the house of the index case is surrounded by fruit trees frequently visited by fruit bats. There is a high probability that Kampar virus originated from bats and was transmitted to humans via bat droppings or contaminated fruits. The discovery of Kampar virus highlights the increasing trend of emergence of bat zoonotic viruses and the need to expand our understanding of bats as a source of many unknown viruses. - Funding: This work was supported in part by institute funding from the National Public Health Laboratory of Malaysia and the Australian Animal Health Laboratory. Competing Interests: The authors have declared that no competing interests exist. Reoviruses (respiratory enteric orphan viruses), members of the family Reoviridae, are a large and diverse group of non-enveloped viruses with segmented dsRNA genomes, which are taxonomically classified into ten genera [1,2]. Members of the genus Orthoreovirus contain 10 genome segments and have been isolated from a broad range of mammalian, avian and reptilian hosts. Although orthoreoviruses have been identified as the causative agents of diseases in animals, infections in humans are generally benign with very rare cases of mild upper respiratory tract illness or enteritis in infants or children [3]. Orthoreoviruses are divided into two subgroups, fusogenic and nonfusogenic, based on the ability of the virus to induce cell-cell fusion and syncytium formation [4]. A fusogenic orthoreovirus, the Melaka virus (MelV), was isolated from a human patient suffering acute upper respiratory disease [5]. MelV was shown to be capable of human-to-human transmission and has close sequence relatedness to two bat-borne orthoreoviruses, the Nelson Bay virus (NBV) isolated from fruit bats in Australia and the Pulau virus (PulV) isolated from fruit bats in Malaysia [6,7]. Epidemiological tracing suggested that MelV originated from bats and was transmitted directly to the index case, followed by subsequent transmission to other members of the same family [5]. Bats have been shown to be the reservoir hosts of many recently emergent zoonotic viruses, including Hendra virus, Nipah virus, Menangle virus, and potentially SARS and Ebola viruses [813]. NBV was the first reovirus of bat origin, which was isolated in 1968 from the heart blood of a flying fox (Pteropus poliocephalus) in New South Wales, Australia [6,14]. NBV was also the first mammalian reovirus to display fusogenic properties [6], a characteristic previously only known for avian reoviruses (ARVs). In 1999, during a search for Nipah virus in pteropid bats on Tioman Island, PulV was isolated from Pteropus hypomelanus [7,15]. Here, we report the discovery and characterization of Kampar virus (KamV), the fourth member in the NBV species group and its isolation from a human patient with fever and acute respiratory illness. Although there is no direct evidence to suggest that KamV originated from bats, the close relationship of KamV with other members of the NBV group and preliminary epidemiological data suggest that KamV is most likely a batborne orthoreovirus. Clinical symptoms and case history of patients involved in this study To mitigate the potential health as well as socio-economic impact of emerging diseases, in particular, the potential emergence of pandemic influenza, the Ministry of Health Malaysia undertook nation-wide influenza-like illness surveillance for early detection, identification and control of these emerging diseases. In August 2006, as part of the surveillance process, a patient with acute influenza-like illness was investigated in Kampar, a town situated in the north-western part of peninsular Malaysia, about 36 kilometres south of Ipoh, the capital city of the state Perak. Case 1 (index case). Subject 1 (S1), a 54-year old Chinese man, was well until 19 August 2006 when he developed sudden onset of high fever with chills and rigor. This was associated with cough, sore-throat and headache. There was no associated dyspnoea, tachypnoea, haemoptysis or chest pain on coughing. Besides the severe frontal throbbing headache, he had generalized body aches, myalgia and severe malaise. On the following day, he developed nausea, vomiting and diarrhoea. The vomitus consisted of food taken and was not bile-stained. The stool was described as watery without excessive mucous and it was non-malenic. The gastrointestinal symptom was associated with abdominal pain and loss of appetite. His illness was not relieved with self-medication of antipyretics. On review, there was no associated giddiness, blurring of vision, photophobia, skin bleeding or arthritis. He sought medical treatment at the government health clinic in Kampar on 21 August 2006. At the outpatient clinic, he was noted to be febrile (an axillary temperature of 40.1 degree Celsius), illlooking with a generalized body erythema that blanched on pressure and was more prominent (...truncated)