The University of Malaya announces the identification of a third enterovirus involved in the present outbreak of hand, foot and mouth disease (HFMD). This virus, known as echovirus 7 or echo 7 (UM strain), was isolated from a fatal case in Universiti Hospital Kuala Lumpur (UHKL). The identification of this virus was conducted by Assoc. Prof. Dr. Chua Kaw Bing, consultant virologist of UHKL, along with clinical virologist Dr. Peter McMinn at the Princess Margaret Hospital, Perth.
The virus was rapidly identified within 2 days by Dr. Chua and Dr. McMinn using molecular sequencing of the viral capsid protein genes which showed that the echo 7 UM strain is more closely related to echo 7 virus recently isolated in Spain than the classical Wallace strain isolated over 30 years ago in America. Further confirmation was obtained within a week by a neutralization assay using the complete set of enterovirus reagents from Perth. According to Dr. Chua and Dr. McMinn, the virus is definitely not enterovirus 71.
Echovirus 7 is a member of the enterovirus family and is not commonly associated with severe human infection. According to Prof. Lam Sai Kit, senior consultant virologist of UHKL, there are over 30 echoviruses known but these are usually not associated with such serious infections. In the literature, there have been several outbreaks due to echo 7 virus involving the central nervous system. One such outbreak in Pondicherry, India, was published in 1969 where there were 26 cases of encephalitis with several deaths. In Sweden in 1973, an outbreak of meningoencephalitis due to echo 7 and Coxsackie B3 was reported and echo 7 was isolated from 19 patients. There was no fatality during this outbreak.
During the present hand, foot and mouth outbreak, several enteroviruses have been isolated by UHKL. These included seven Coxsackie A16, fourteen enterovirus 71, one Coxsackie B, twelve herpes simplex and six echo 7. However, five of the six echo 7 virus isolates were from severe and fatal encephalitis. Dr. Chua thinks this indicates that the present strain is probably more virulent than previously existing strains.
Prof. Lam thinks that identification of a third enterovirus by the UHKL team during the present outbreak is of interest globally because of the increase in emerging and re-emerging diseases worldwide. It should not affect the control measures initiated by the Ministry of Health since it is directed against all enteroviruses and the public should continue to adhere to advice from the Ministry.
A one-day seminar on hand, foot and mouth disease is being organized by the University of Malaya Medical Centre jointly with the Ministry of Health Malaysia. Assoc. Prof . Hamimah Hassan, Head of the Department of Medical Microbiology and chairperson of the organizing committee said that the seminar, to be held on 31 October 2000 at UHKL, is open to all health professionals and the objective is to disseminate information on HFMD to fellow doctors and colleagues.