GOF study shows serial pig infection can enhance H9N2 transmissibility
In a gain-of-function (GOF) experiment, Belgian researchers showed that serial passaging of H9N2 avian flu viruses in pigs enhanced the virus's replication and transmissibility, the scientists reported yesterday in PLoS One.
Using an H9N2 virus isolated years ago from a quail in Hong Kong, the team performed multiple serial passages—consecutive infections—in flu-free swine to assess the potential of the pathogen to adapt to swine. The initial virus produced positive lung samples in half the pigs, but after four passages, the pigs had viral replication in their entire respiratory tract, resulting in 100% of H9N2-positive lung samples.
Viral shedding also increased. Whereas only one out of six contact pigs showed nasal virus excretion of the wild-type H9N2 for more than 4 days with the initial virus, all six contact pigs shed H9N2 after four passages.
The authors conclude, "Our data demonstrate that serial passaging of H9N2 virus in pigs enhances its replication and transmissibility. However, full adaptation of an avian H9N2 virus to pigs likely requires an extensive set of mutations."
GOF studies enhance the pathogenicity, transmissibility, or host range of a pathogen to learn more about it. They have triggered "dual-use" concerns—that methods meant for beneficial purposes could be used to create bioterror threats or for other nefarious purposes.
Apr 6 PLoS One study
More H7N9 cases reported across a wide part of China
Mainland China reported 14 new H7N9 avian flu cases, one of them fatal, over the past week, signaling continuing but slowing disease activity during the unprecedented fifth wave of activity, according to a regular update today from Hong Kong's Centre for Health Protection (CHP).
Three of the illnesses were reported from Beijing and one was from Tibet, part of a broader distribution of cases that has marked China's current H7N9 season. It's not clear if the Beijing cases were locally acquired or imported. Earlier this season, two patients were hospitalized in Beijing with H7N9 infections that appeared to have been contracted in other provinces.
Meanwhile, Gansu province's health department today announced what appears to be its first ever H7N9 case, according to an official statement translated and posted by FluTrackers, an infectious disease news message board. Gansu province is in northwestern China; most of the human cases have been reported in the southeast.
The patient is an 82-year-old man from Suzhou who sought treatment on Apr 3 and whose samples tested positive yesterday. He is hospitalized in serious condition, and his illness prompted an investigation of poultry and the temporary closure of all live-poultry markets in the city.
Regarding the cases reported in the CHP statement, illness onsets ranged from Mar 14 to Apr 4, with cases reported in two municipalities—Beijing and Chongqing—and six provinces. Thirteen patients had a history of exposure to poultry or poultry markets, known risk factors for the disease.
Flu activity decreases in United States
In its weekly influenza report, FluView, the Centers for Disease Control and Prevention (CDC) said flu was on the decline in the United States, but activity was still elevated.
Despite the decline, there were seven more pediatric flu deaths reported last week, bringing the season's total to 68.
According to this week's data, the overall hospitalization rate for influenza-like illness (ILI) rose to 57.2 per 100,000 population, up from last week's 54.1 per 100,000 population. According to FluView, adults over the age of 65 had the highest rate of hospitalizations at 256.0 per 100,000 population, followed by adults aged 50 to 64 (56.5 per 100,000 population) and children aged 0 to 4 years (39.5 per 100,000 population).
The proportion of outpatient visits for ILI was 2.9%, which is above the national baseline of 2.2%. Nine states reported high influenza-like illness (ILI) activity; five states experienced moderate ILI activity; New York City and nine states experienced low ILI activity; Puerto Rico and 27 states experienced minimal ILI activity.
For the first time in the season, the week's lab-confirmed influenza specimens were predominately influenza B (60.9%), with influenza A detected in 39.1% of the specimens.
Apr 7 CDC FluView
Brazil changes yellow fever vaccine recommendations
Brazil's Ministry of Health announced they are changing their yellow fever immunization recommendation from two doses to one, according to a report from a daily newspaper based in Sao Paulo.
Historically, the country has recommended one initial dose of the vaccine with a second given 10 years later. The change follows the World Health Organization 2014 recommendation, which stated that one dose of yellow fever vaccine provided lifelong immunity from the mosquito-borne disease.
According to the Brazilian health ministry, people who have received the first dose no longer require a second. This change could help stretch the yellow fever vaccine supply as the country undergoes vaccination campaigns in the wake of the current outbreak that began in January.
The primary supplier in Brazil, Bio-Manguinhos at the Fiocruz Institute, has been producing more than 8 million doses per month, and the country has also acquired 3.5 million doses from the WHO's international fund.
The Brazilian ministry of health said there's no shortage of vaccine, but demand is high.
Apr 6 Fohla de S. Paulo article
More than 20% US adults have high-risk HPV
New CDC data show that nearly 23% of Americans in 2013-2014 had a high-risk strain of human papilloma virus (HPV), which has been linked to cervical cancer. Nearly double that percentage, 42.5%, tested positive for any kind of genital HPV.
The data collected from the National Health and Nutrition Examination Survey show that men have more HPV than women. During 2013–2014, genital HPV prevalence among adults ages 18 to 59 was 42.5% in the total population, 45.2% among men, and 39.9% among women; high-risk genital HPV prevalence was 22.7% in the total population, 25.1% among men and 20.4% among women.
Men also had more instances of high-risk oral HPV. Between 2011 and 2014, the prevalence of oral HPV among adults ages 18 to 69 was 7.3% and high-risk oral HPV was 4.0%. Prevalence was highest among non-Hispanic blacks of any and high-risk oral HPV was lowest among
non-Hispanic Asian adults, and any oral HPV was highest among non-Hispanic black adults.