US flu activity declines, but virus still taking lives
Overall US influenza activity continues to decline, but the share of deaths attributed to flu and pneumonia is still on the high side, the Centers for Disease Control and Prevention (CDC) said today in its weekly update.
Of the other indicators, the proportion of medical visits due to flu-like illness fell last week for the ninth week in a row, putting it back at the national baseline of 2%. Nationally, the percentage of respiratory specimens that tested positive for flu decreased to 8.7%, but over the past 3 weeks that level has varied by region, from 5.8% to 22.4%, the CDC said.
The percentage of deaths due to flu and pneumonia rose to 7.9% last week after declining for 4 weeks, keeping it above the epidemic threshold. Four more pediatric flu deaths were reported, putting the season's total at 65.
Health officials haven't raised concerns about the overall number of deaths this season, but they have said the death toll in young and middle-aged adults appears higher than normal, probably because the 2009 H1N1 virus is dominant.
The 2009 H1N1 virus continues to dominate, but last week 20% of the viruses that circulated were influenza B, up from 17% the week before. Tests identified six more 2009 H1N1 isolates that showed resistance to oseltamivir (Tamiflu), bringing the season's total to 34.
Only one state—Hawaii—reported high flu-like illness activity, while eight states reported that cases were geographically widespread, down from 10 the week before.
European health officials last week saw a fairly wide variation in flu activity by country. The European Centre for Disease Control and Prevention (ECDC) said today that the overall proportion of positive respiratory samples decreased for the sixth week in a row to 34%, but seven countries reported increasing flu trends: Austria, Belgium, Croatia, Estonia, Greece, Poland, and Romania.
Influenza A viruses are predominant in Europe, with the 2009 H1N1 virus a heavy player in hospital cases, the agency said. Labs have detected only a few influenza B viruses.
Mar 7 CDC FluView report
Mar 7 CDC situation update
Mar 7 ECDC weekly influenza report
Cambodian boy dies from H5N1 infection
A 3-year-old Cambodian boy has died from an H5N1 avian influenza infection, the country's sixth case this year, according to a joint statement today from the country's health ministry and the World Health Organization (WHO).
The boy, from Phnom Penh, started having symptoms on Feb 22, including fever, cough, runny nose, and vomiting. His parents took him to the doctor the same day, but his condition worsened, and he was admitted to a hospital on Feb 28. When he experienced dyspnea and cyanosis, the medical team transferred him on Mar 2 to another hospital, where he died an hour after admission. Tests at two labs confirmed his H5N1 infection on Mar 3.
Investigators found that 90% of the village's chickens and a small number of ducks had suddenly died the week before the boy got sick, and though he had no direct contact with chickens, he often visited a neighbor's home where poultry had recently died.
Cambodia has reported 53 H5N1 cases, 35 of them fatal, since 2005, when the first human infection was reported there.
Mar 7 Cambodian health ministry/WHO statement
Vietnam reports more H5N1 outbreaks, problems with poultry vaccine
Outbreaks of H5N1 avian flu in poultry have been reported in four areas of Vietnam, according to postings from the World Organization for Animal Health (OIE) yesterday and today. The current rash of outbreaks there began last fall after a several-month quiet period.
The new outbreaks are in widespread locations. The southern Binh Duong province reported 300 poultry deaths out of 710 susceptible birds. Ninh Thuan, another southern province, had 600 deaths out of 1,210 susceptible birds. All the remaining birds in the affected flocks were destroyed.
Can Tho province, farther south, reported 5,812 H5N1-infected poultry with 500 deaths among 7,512 susceptible birds, and the south-central Gia Lai province cited 260 cases with 160 deaths among 731 birds. Again, the remaining birds in the flocks were destroyed.
In related news, an H5N1 mutation that increases resistance to poultry vaccines in Vietnam was reported today by Thanh Nien News. The mutation was confirmed in Tra Vinh province in the Mekong Delta.
An official there said the poultry vaccine normally used is having weaker effects this year than previously and encouraged farmers to use a new vaccine, says the story. Birds vaccinated with the former vaccine have been falling ill.
He said samples of sick poultry would be tested for the mutation. The story says an average of two new outbreaks has been occurring in the country every day since early February. Further spread of the virus with cold weather is expected.
Mar 7 Thanh Nien News story