Jul 12, 2012 (CIDRAP News) – A joint investigation into dozens of puzzling lethal respiratory illnesses in Cambodian children concluded that the infections were caused by a severe form of hand, foot, and mouth disease (HFMD), the World Health Organization (WHO) and Cambodia's health ministry said today in a statement.
Earlier this week, the agencies said lab analysis of samples from several of the patients pointed to enterovirus 71 (EV-71), which can cause a severe form of HFMD in some patients.
In their wrap-up of the investigation, the groups said the findings include a review of hospital records on children treated at Kantha Bopha Children's Hospital, which reported unusual numbers of illnesses and deaths since April, and records from other hospitals.
The probe also included a review of lab tests, follow-up of affected families by rapid response teams, and analysis of disease data from Cambodia's surveillance system. The Pasteur Institute in Cambodia and the US Centers for Disease Control and Prevention (CDC) assisted with the investigation.
Officials identified 78 cases, including 62 initially reported from Kantha Bopha Hospital. Investigators focused on 61 cases that fit the case definition, which included 54 deaths. The Pasteur Institute tested samples from 31 patients, and most were positive for EV-71. A few were positive for other pathogens, including Haemophilus influenzae type B and Streptococcus suis, according to the statement.
Most of the patients were under age 3, and some were affected by chronic conditions and malnutrition. The children were from 14 different provinces.
Investigators found that many of the patients had been given steroids at some point in their illness, which can worsen the condition of patients with EV-71 infections, the statement said.
In response to the illnesses, Cambodia's health ministry, with WHO support, has launched enhanced surveillance for neurorespiratory syndrome, a key feature observed in some patients with severe HFMD caused by EV-71. Officials have asked health centers to also report patients with mild HFMD infections. The statement said officials expect to identify occasional new cases of the severe form of the disease in the months ahead.
Health officials are also developing guidelines and training courses for managing patients with both mild and severe HFMD.
The statement said HFMD is not a new disease in Cambodia, but it did not say if illnesses linked to EV-71 had been detected before.
HFMD is common in many Asian countries. A Jun 26 HFMD surveillance update from the WHO's Western Pacific Region office (WPRO) noted that seven countries or administrative regions have reported cases this year, most of them in China, Vietnam, and Singapore.
In other developments, health authorities in the Philippines on Jul 10 made EV-71 infection a reportable illness, which requires individuals and health facilities to report infections to public health officials, Rappler.com, a social news network based near Manila, reported yesterday. The country's department of health said yesterday that it would soon release guidelines on reporting EV-71 illnesses.
Philippines health officials said no travel restrictions are needed for people traveling to and from Cambodia, though officials are screening in-bound travelers at all points of entry, according to the report.
Jul 12 WHO and Cambodian health ministry joint statement
Jun 26 WHO WPRO HFMD update
Jul 11 Rappler story