H5N1

Eurosurveillance: Point-of-care tests for H7N9

Via Eurosurveillance: A comparison of rapid point-of-care tests for the detection of avian influenza A(H7N9) virus, 2013. The abstract:

Six antigen detection-based rapid influenza point-of-care tests were compared for their ability to detect avian influenza A(H7N9) virus. The sensitivity of at least four tests, standardised by viral infectivity (TCID50) or RNA copy number, was lower for the influenza A(H7N9) virus than for seasonal A(H3N2), A(H1N1)pdm09 or other recent avian A(H7) viruses. Comparing detection limits of A(H7N9) virus with Ct values of A(H7N9) clinical specimens suggests the tests would not have detected most clinical specimens.

Butler: New avian flu readily transmits in key animal model

Via Nature News & Comment, Declan Butler reports on the Zhu paper published online yesterday: New avian flu readily transmits in key animal model. Excerpt:

The relative ease of spread between ferrets is in sharp contrast to what has been observed so far in the human outbreaks that were first reported in March. It is possible that person-to-person spread occurred in three family clusters of H7N9 cases, but so far there is no firm evidence of this. 

Malik Peiris, a flu virologist at the University of Hong Kong and a co-author of the latest study, says that all flu viruses that spread easily between humans are also transmissible by air between ferrets. Flu infections that do not spread easily between humans, such as H5N1, do not transmit via the air between ferrets. 

What the latest work shows, he says, "is that this virus is closer to acquiring human-to-human transmission than other pandemic candidates out there, but not as transmissible as true seasonal [flu] viruses or pandemic 2009 H1N1". 

The ferrets’ flu symptoms were limited to sneezing, coughing, runny noses and mild lethargy, in contrast with the severe disease seen in humans. Although ferrets show many aspects of human flu infections, the animals are an "imperfect model" for flu virulence in humans, says Frederick Hayden, a flu virologist at the University of Virginia in Charlottesville. 

"It's self-evident that the best study of human disease is the study of humans with the disease," but the ferret studies complement these, says Peiris. He also says that autopsy data from human H7N9 cases is scarce and often reflects late-stage infection, for example, and so it does not capture the early stages of the disease. Data from infected humans, from cultured human cells and from animal experiments "all provide important and different dimensions of the questions we want to address,” Peiris says. “No one approach will give all the answers."

H7N9 found to spread through the air

The South China Morning Post has promptly picked up the Science report mentioned here earlier today: H7N9 bird flu found to spread through the air. Excerpt:

The H7N9 bird flu virus can be transmitted not only through close contact but by airborne exposure, a team at the University of Hong Kong found after extensive laboratory experiments. 

Though the virus appears to have been brought under control recently, the researchers urged the Hong Kong authorities to maintain strict surveillance, which should include not only poultry but humans and pigs. 

"We also found that the virus can infect pigs, which was not previously known," said Dr Maria Zhu Huachen, a research assistant professor at HKU's School of Public Health. 

There have been 131 confirmed human infections, with 36 deaths, the World Health Organisation said. All but one of the cases was on the mainland. The virus appears to have been brought under control largely due to restrictions at bird markets and there have been no new confirmed cases since May 8. 

But Zhu said that although there was no evidence of sustained human-to-human transmission, their study provided evidence that H7N9 was infectious and transmissible in mammals. 

In the study, to be published today in the journal Science, ferrets were used to evaluate the infectivity of H7N9. It was found the virus could spread through the air, from one cage to another, albeit less efficiently. 

Inoculated ferrets were infected before the appearance of most clinical symptoms. This means there may be more cases than have been detected or reported. 

"People may be transmitting the virus before they even know that they've got it," Zhu said. 

Additional tests using pigs, a major host of influenza viruses, showed that they could also get infected with H7N9. Zhu warned that H7N9 may combine with pig viruses to generate new variants. 

On a more positive note, it was found that the virus is relatively mild. 

"Most of the fatal H7N9 cases had underlying medical conditions, so there are probably some other factors that contribute to this kind of fatality," Zhu said.

China: No H7N9 virus found in poultry farms

Via Xinhua: No H7N9 virus found in poultry farms: MOA. Excerpt:

The H7N9 bird flu virus has not been detected in poultry farms, with positive samples mainly coming from live poultry markets, China's Ministry of Agriculture (MOA) said Thursday. 

The MOA said it has "basically" finished collecting and testing 899,758 samples from across most parts of the country. 

Of the total, 53 samples were found positive with H7N9. Fifty-one positive samples were from 18 live poultry markets in Shanghai, Anhui, Zhejiang, Jiangsu, Henan, Shandong, Guangdong, Jiangxi and Fujian, the MOA said in a statement. 

The other two positive samples were from wild pigeons in Nanjing, capital of Jiangsu Province and domestic pigeons in Nantong, in Jiangsu Province. 

Experts believe live poultry markets pose more danger and farms should step up efforts to guard against the virus, the statement said. 

The H7N9 virus is not lethal to chicken and ducks, according to research from the national bird flu reference laboratory. 

Also, no pigs were found to have caught the virus, the MOA said.

China: Scientists make new H7N9 claim

Via People's Daily Online, a Shanghai Daily report: Scientists make new H7N9 claim. Excerpt:

Scientists at Fudan University claimed yesterday that the H7N9 bird flu virus originated from poultry or wild bird in eastern China instead of the previous theory that the virus's two major proteins - HA and NA - come from fowl in China and South Korea respectively. 

The scientists said their findings were based on generic research and analysis through advanced bioinformatics and it can be important to prevent bird flu in the future. 

The new results were published in the latest edition of the US-based Clinical Infectious Diseases. 

Since February 19, the flu-like symptoms first started to appear in eastern China and the National Health and Family Planning Commission announced the discovery of the new H7N9 virus on March 31. 

Previously, scientists - both at home and abroad - believed that the virus's HA of the H7 subtype came from duck in Hangzhou, Zhejiang Province, and NA of the N9 subtype was from fowl in South Korea. 

But Fudan researchers said from gene sequencing they discovered that NA of the N9 subtype had its origins in Baikal Teal in Hongze Lake in Jiangsu Province.

The original CID article is behind a paywall, or I would link to it.

Live-animal markets and H7N9

Thanks to Greg Folkers for this NEJM letter, published today: Live-Animal Markets and Influenza A (H7N9) Virus Infection. Maybe I've been doing this too long, but it reads like a medical thriller. Excerpt:

A recent outbreak of a previously unrecognized novel reassortant avian influenza A (H7N9) virus in China had resulted in 131 documented cases and 36 deaths as of May 16. Although some patients had a history of contact with live poultry or visiting live-animal markets before the onset of illness, the source of infection remains unclear. 

A 45-year-old woman was admitted to a hospital on March 23, 2013, with a 5-day history of fever (temperature, 41.0°C), cough, expectoration, malaise, and shortness of breath. Computed tomography of the chest that was performed 2 days before admission showed infection in the right lung. On March 28, a specimen of tracheal secretion from the patient was collected for laboratory testing. Epidemiologic investigation showed that the patient was otherwise healthy except for a positive assay for hepatitis B surface antigen. 

She had worked for several years in a live-animal market as the sole poultry butcher. Her stall was located in a corner of the market (red dot in Fig. S1 in the Supplementary Appendix, available with the full text of this letter at NEJM.org). Except for the definite exposure from her working environment, she had had no contact with other animals or febrile patients. All the live poultry she slaughtered came from a neighboring stall (green dot in Fig. S1 in the Supplementary Appendix). The live poultry had been purchased from a secondary wholesale market, where poultry raised on various farms were congregated before being sold to live-animal markets. 

Laboratory investigation by means of various methods — including real-time reverse-transcriptase–polymerase-chain-reaction (RT-PCR) assay, viral isolation, and full-genome sequencing — confirmed that the patient was infected with the novel H7N9 virus. 

To trace the possible source of infection, investigators collected 5 environmental samples from the two stalls in the market and 13 samples from the secondary wholesale market on March 29. One poultry-cage specimen from the neighboring stall was positive for the novel H7N9 virus. 

Furthermore, mixed avian-influenza viral nucleic acids (e.g., subtypes H3, H7, N8, and N9) were detected on subtype-specific real-time RT-PCR from one feces sample collected from the secondary wholesale market. 

Two viral strains, one from the patient (Nanjing/1) and one from poultry-cage specimens obtained in the neighboring stall (Env/Nanjing), were successfully isolated (GenBank numbers, KC896771-KC896778 for the case specimen and KC896763-KC896770 for the environmental specimen). 

Genome comparison showed that the similarity in the nucleic acids found in the two isolates ranged from 98.9% to 100%; this would translate into an amino acid similarity of 98.2% to 100%. Both isolates had potentially functional amino acid sites related to mammal- or human-adapting substitution T189A, Q226L, and G228S (H3 numbering) in the receptor-binding site of hemagglutinin. 

The two isolates showed E rather than K at position 627 of BP2. However, Nanjing/1 showed K rather than Q at position 591 of PB2, which has been shown to cooperate with position 627 of PB2, and the combination of 591K–627E showed higher virulence than that of 591Q–627E in mice with H5N1 viruses4 (Table S1 in the Supplementary Appendix). 

These findings suggest that the novel virus had been evolving and might, with a few amino acid mutations, adapt to humans.

H7N9: Clinical findings in 111 cases

Thanks again to Greg Folkers for sending the link to this NEJM article, published today: Clinical Findings in 111 Cases of Influenza A (H7N9) Virus Infection. The abstract:

BACKGROUND 

During the spring of 2013, a novel avian-origin influenza A (H7N9) virus emerged and spread among humans in China. Data were lacking on the clinical characteristics of the infections caused by this virus. 

METHODS 

Using medical charts, we collected data on 111 patients with laboratory-confirmed avian-origin influenza A (H7N9) infection through May 10, 2013. 

RESULTS 

Of the 111 patients we studied, 76.6% were admitted to an intensive care unit (ICU), and 27.0% died. The median age was 61 years, and 42.3% were 65 years of age or older; 31.5% were female. A total of 61.3% of the patients had at least one underlying medical condition. Fever and cough were the most common presenting symptoms. 

On admission, 108 patients (97.3%) had findings consistent with pneumonia. Bilateral ground-glass opacities and consolidation were the typical radiologic findings. Lymphocytopenia was observed in 88.3% of patients, and thrombocytopenia in 73.0%. Treatment with antiviral drugs was initiated in 108 patients (97.3%) at a median of 7 days after the onset of illness. 

The median times from the onset of illness and from the initiation of antiviral therapy to a negative viral test result on real-time reverse-transcriptase–polymerase-chain-reaction assay were 11 days (interquartile range, 9 to 16) and 6 days (interquartile range, 4 to 7), respectively. 

Multivariate analysis revealed that the presence of a coexisting medical condition was the only independent risk factor for the acute respiratory distress syndrome (ARDS) (odds ratio, 3.42; 95% confidence interval, 1.21 to 9.70; P=0.02). 

CONCLUSIONS 

During the evaluation period, the novel H7N9 virus caused severe illness, including pneumonia and ARDS, with high rates of ICU admission and death.

H7N9 bird flu outbreak costs more than $6.5 billion so far: UN

Via The Star: H7N9 bird flu outbreak costs more than $6.5 billion so far: UN.

The H7N9 virus appears to have been brought under control in China largely due to restrictions at bird markets, but caused some $6.5 billion in losses to the economy, UN experts said on Tuesday. 

The new bird flu virus is known to have infected 130 people in mainland China since emerging in March, including 36 who died, but no cases have been detected since early May, Health Minister Li Bin told a meeting of the World Health Organization. One case was found in Taiwan in April, making a total of 131. 

H7N9 is nearly impossible for farmers to detect, unlike H1N1 which kills off flocks, said Juan Lubroth, chief veterinary officer at the UN’s Food and Agriculture Organization (FAO). 

“Economic impacts of H7N9 have been astounding,” he said. 

“Over $6.5 billion has been lost in the agriculture sector because of prices, consumer confidence and trade. So poultry industry losses in China have been high,” Lubroth said, later making clear it was an estimate by China’s agriculture ministry. 

Li said local Chinese authorities had shut down live poultry markets “temporarily or permanently as needed” to control the source of outbreaks in 10 provinces. It standardized methods of transporting poultry to reduce spread among birds. 

China’s government had spent 600 million RMB or $97 million to support healthy development of the poultry industry, Li said. 

“The immediate outbreak has been controlled, but it is also unlikely that virus has simply disappeared. We believe we need go another autumn/winter/spring season to know,” said Keiji Fukuda, WHO assistant director-general for health security. 

There was no evidence of sustained spread among people and “most cases probably resulted from infected poultry or perhaps contamination related to live poultry markets,” Fukuda said. 

“There have been no (human) cases since May 8; that is a good indication and means measures are being taken seriously,” Bernard Vallat, head of the World Organization for Animal Health (OIE), told reporters. “Now when the virus is found at market, all birds are killed. That is important, too.” 

Out of 60,000 samples taken from birds, 53 were found to carry the virus, Liang Wannian of China’s health ministry said.

And that minuscule number of positives explains how little we still know about H7N9, and why we'll have to be on the alert for it, indefinitely.

CIDRAP: News scan for May 21

Via CIDRAP: NEWS SCAN: H5N1 in Cambodia, low-path avian flu in Spain, Tamiflu stockpile questions. Excerpt:

Another H5N1 avian flu case has surfaced in Cambodia, that of a 5-year-old girl whose illness was detected retrospectively, according to a May 17 update from the World Health Organization (WHO) Western Pacific Region office. 

Her illness, which began on Jan 28, was found during a fever surveillance study conducted by the US Naval Medical Research Unit (NAMRU). Her respiratory samples tested positive for H5N1 on May 2. 

The girl is from a village in Kampong Speu province. She is alive, and health officials are investigating her exposure to poultry, the WHO said. 

The latest infection raises Cambodia's total number of H5N1 cases to 32, which includes 27 deaths. Her illness is the country's 11th H5N1 case reported this year.

Bird flu outbreak costs China's poultry industry US$65b

Via South China Morning Post: Bird flu outbreak costs China's poultry industry US$65b. Excerpt:

China’s human H7N9 bird flu outbreak has cost the country’s poultry industry more than 400 billion yuan (HK$500 billion) as consumers shun chicken, government officials said according to state media Monday. 

The sector has been losing an average of one billion yuan a day since the end of March, the Beijing Times said, citing Li Xirong, head of the National Animal Husbandry Service. 

H7N9 avian influenza has infected 130 people in China, killing 35, since it was found in humans for the first time, according to latest official data. 

Poultry sales have tumbled and prices plunged, Li said, causing major financial problems and job losses as a result. 

Another agriculture ministry official, Wang Zongli, said government agencies should set a good example for the public by treating “poultry products in a correct way”, the report added. 

In a stunt to boost confidence, officials and poultry business leaders in the eastern province of Shandong held a widely reported all-chicken lunch last week, according to Chinese media.

On April 10, 2003, then-Prime Minister Jean Chretien and several Liberal MPs had a very public lunch in a Toronto Chinese restaurant, simply because the public had associated SARS, irrationally, with Chinese food.