Human Adenovirus Type 7 Outbreak in Police Training Center, Malaysia, 2011

Mohd Apandi Yusof

, Tengku Rogayah Tengku Abdul Rashid, Ravindran Thayan, Khairul Azuan Othman, Norhasnida Abu Hasan, Norfaezah Adnan, and Zainah Saat

Author affiliations: Institute for Medical Research, Kuala Lumpur, Malaysia

Abstract

In March 2011, an outbreak of acute respiratory disease was reported at the Kuala Lumpur (Malaysia) Police Training Centre. Approximately 100 trainees were hospitalized and 5 were admitted to the intensive care unit. Three of these 5 trainees died. Human adenovirus type 7 was identified as the etiologic agent.

Human adenoviruses (HAdVs) consist of nonenveloped, double-stranded DNA and belong to the family Adenoviridae, genus Mastadenovirus. The 51 recognized serotypes of human adenoviruses have been placed in 7 human adenovirus species, A–G (1). These viruses cause infections ranging from mild syndromes to severe, life-threatening disease.
Depending on the species, these viruses may infect respiratory, conjunctival, gastrointestinal, and genitourinary sites. They have been recognized for decades as the primary causes of acute respiratory disease (ARD), gastrointestinal infection, and fever (2). Outbreaks of adenoviruses associated with respiratory disease have been reported worldwide (3,4) and commonly occur among the military trainees (5,6). These cases of ARD are most frequently associated with a strain of HAdV-B, HAdV-7 (7).
We describe the emergence of HAdV-7 in Malaysia. The outbreak occurred during March–April 2011 and involved new police recruits in the Kuala Lumpur Police Training Centre. Approximately 100 trainees were admitted to the Kuala Lumpur Hospital, and 4 more were treated in the intensive care unit. This outbreak affected 851 police trainees and claimed 3 lives.

The Study

In April 2011, the virology unit at the Institute for Medical Research, Kuala Lumpur, received respiratory samples from police trainees admitted to Kuala Lumpur Hospital with ARD and tissue samples from 2 of the 3 patients with fatal cases. The postmortem specimens consisted of cerebrospinal, pericardial effusion, and pleural effusion fluids; lung, liver, spleen, and kidney tissues; skin; and bone marrow aspirate.
Viral nucleic acid was extracted from the clinical samples by using Roche High Pure Viral Nucleic Acid Kit (Roche Applied Science, Mannheim, Germany). Of the initial samples, 10 were screened for respiratory syncytial viruses, influenza viruses, parainfluenza viruses, human metapneumoviruses, coxsackieviruses, echoviruses, rhinoviruses, coronaviruses, adenoviruses, and bocavirus by multiplex PCR. All samples were then subjected to adenovirus nucleic acid detection by PCR.
Partial HAdV hexon gene was amplified by PCR (8). The SeqMan and Megalign software modules in the Lasergene suite of programs (DNASTAR, Madison, WI, USA) were used to format the nucleotide sequences. A phylogenetic tree was constructed by using the neighbor-joining method from the MEGA4 software (www.megasoftware.net

).
A total of 33 clinical specimens, including respiratory and fecal samples as well as postmortem samples, from 21 trainees admitted to Kuala Lumpur Hospital were collected. Of these, only 31 samples from 19 trainees were sufficient for analysis. PCR or reverse transcription PCR was performed on 10 of the 31 samples by using primer sets specific for respiratory viruses with the ResPlex II Panel (QIAGEN, Valencia, CA, USA). The 10 samples contained HAdV-B species.