Hand hygiene still key to mitigating HFMD epidemics
Proper disinfection of hands and surfaces remains the main weapon to stem outbreaks of hand, foot and mouth disease (HFMD), according to a virologist.
“The HFMD viruses are highly contagious as they spread easily through physical contact or from contaminated surfaces,” said Privatdozentin Dr. Maren Eggers, head of Virology and Disinfectant testing at the Labor Prof. G. Enders & Partner, Germany. “As antivirals and vaccines are not available (for HFMD), basic hygiene is the only way to prevent infection.”
Since the first locally recorded outbreak of HFMD in 1997—resulting in 41 fatalities among infants and young children in Sarawak—epidemics have struck Malaysia in cycles of 2 to 3 years, with a majority of cases attributed to Enterovirus 71 (EV-71) and Coxsackievirus A16 (CVA16). One of the most severe national epidemics occurred in 2016, during which 23,454 cases were reported by the MOH between January and August. [Virol Sin 2011;26(4):221–228]
Transmission of HFMD occurs via direct contact with infected bodily fluids, blister fluids and faeces. After an incubation period of 3 to 5 days, HFMD’s initial symptoms include fever, poor appetite, malaise, and sore throat. Within 1 to 2 days of initial symptoms, small, painful oral sores develop, beginning as small red spots which may blister and become ulcers. Non-itchy blister-like rashes subsequently form on the hands, feet and mouth, as well as the buttocks and genitalia in some cases.
“Most mild HFMD patients recover fully after the acute illness in 7 to 10 days,” said Eggers. “However, there are severe cases of HFMD in which patients develop viral meningitis or encephalitis or even poliomyelitis-like paralysis, and may need to be hospitalized for several days.”
Speaking at the recent launch of an antiseptic skin cleanser in Kuala Lumpur, Eggers cautioned that alcohol and phenolic disinfectants—typically used in hand sanitizers—lack efficacy against non-enveloped viruses such as the enteroviruses which cause HFMD, and recommended active ingredients with proven virucidal effect, such as povidone-iodine. She added that as viral loads persist in the stools of recovered patients for up to 2 months, maintaining strict disinfection practices is paramount during seasonal epidemics.
A recently published study of 2,141 EV-71 antibody-positive serological samples from a single Malaysian hospital—collected from 6 outbreaks between 1995 to 2012—found that outbreaks coincided with the accumulation of a pool of non-immunized children between epidemics, as well as an increase in the virus’s genetic diversity among the population. Incidence rates were highest among children between ages 0 to 2 years, though children up to 13 years old were also susceptible to the disease. [PLoS Negl. Trop. Dis 2016;doi:10.1371/journal.pntd.0004562]
Vaccine development remains challenging due to the genetic diversity of the causative viruses; however, an inactivated whole virus vaccine against EV71 was approved in 2015 by the China Food and Drug Administration, and development of other vaccines is underway in several Asia-Pacific countries including Singapore and Taiwan. [Vaccine 2016;34(26):2967–2970]