Apr 21, 2011 (CIDRAP News) – The World Health Organization (WHO) today announced H5N1 avian influenza infections in two more Egyptians, one of them fatal, as well as an H5N1-related death in a Cambodian girl.
In a separate report reviewing H5N1 infections that were reported in 2010, the WHO said the epidemiologic picture of human cases hasn't changed, with women having more serious outcomes than men and children more likely to have a mild form of the disease.
All three of the new case-patients had been exposed to sick or dead poultry, the WHO said in two separate reports, which were based on information from Egyptian and Cambodian health ministries.
The two patients infected by the virus in Egypt are both from Fayoum governorate, but live in different areas. Fayoum is in central Egypt, southwest of Cairo. The WHO said there are no epidemiologic links between the two cases, and Egypt's health ministry said both patients were treated with oseltamivir (Tamiflu).
One of the Egyptian case-patients is a 29-year-old man who got sick Apr 1 and was hospitalized Apr 4, where he died 3 days later. The other patient is an 18-month-old boy who started having symptoms on Apr 9 and was hospitalized on Apr 11, where he is in stable condition.
The infections and death push Egypt's number of H5N1 cases to 143, including 47 deaths. This year the country has already confirmed 24 H5N1 cases and 7 deaths, compared with 29 cases and 13 deaths in all of 2010.
Cambodia's health ministry said the country's latest case-patient is a 5-year-old girl from Prey Veng province who became ill on Apr 11 and was first treated by local practitioners, according to a WHO statement. She was admitted to the hospital on Apr 16, but died 4 days later. Prey Veng province is in south-central Cambodia.
Respiratory samples from 53 of the girl's contacts were collected and are being tested at the National Institute for Public Health in Phnom Penh.
The girl's infection and death raise Cambodia's H5N1 total to 15 cases, which includes 13 deaths. So far this year Cambodia has reported five H5N1 cases, all of them fatal.
The latest H5N1 cases and deaths boost the WHO's global case count to 552, including 322 deaths.
In other H5N1 developments, the WHO today profiled 48 human cases that were reported in 2010. The report, which appears in the Weekly Epidemiological Record, said all of them were sporadic, and the pattern showed a seasonal peak that occurred between December and March, a trend that paralleled outbreaks in birds.
Egypt reported the highest number of cases, with 29, followed by Indonesia (9), Vietnam (7), China (2), and Cambodia (1).
Most cases occurred in children and young adults; however, the median age of 25 years was higher than the average for past years, mainly because the ages of Egypt's case-patients were higher in 2010.
As in previous years, women made up a larger portion of H5N1 infections in the 20-to-29 age-group; though, overall, the ratio between men and women is almost equal.
Half of the 48 patients died from their H5N1 infections. The case-fatality rate varied by country, with Vietnam the lowest at 28%. As in previous years, the disease was more deadly in women. Patients who survived their H5N1 infections were admitted to the hospital earlier than those who died.
Exposure information was available for 37 of the patients, of which 32 had been exposed to sick and dead poultry. The WHO said that in most areas in which H5N1 cases occur, people have multiple exposures to poultry and environments where the birds are kept, which makes it difficult to determine which factors are most likely to lead to infection.
"It is therefore important for animal health and public health partners to continue to work together to identify and manage common risks and to decrease human exposure at the human-animal interface, particularly in households and in live-bird markets," the WHO said.
Genetic and antigenic evidence showed that during 2010 the viruses continued to diversify, with four different clades represented. However, none of nine human isolates that were sequenced showed mutations linked to oseltamivir resistance. The WHO laboratories also found no signs of reassortment with circulating human influenza viruses.
Apr 21 WHO statement on Egyptian cases
Apr 21 WHO statement on Cambodian case
Apr 22 Wkly Epidemiol Rec report