H5N1

CIDRAP: New H7N9, H5N1 cases

Via CIDRAP: Flu Scan for Feb 24, 2015. Click through for the full report (which also discusses seasonal flu) and numerous links. Excerpt:

H7N9 sickens three more in China

Two of China's provinces—Anhui and Guangdong—reported a total of three new H7N9 avian influenza cases today, according to separate health department reports. 

Anhui province reported two of the case-patients, a 48-year-old man from Ma'anshan and a 75-year-old man from Wuhu, according to a provincial report translated and posted by FluTrackers, an infectious disease news message board. Both are in critical condition and had been exposed to live poultry before they got sick. 

The two infections are Anhui province's first H7N9 cases in the third wave of illnesses that started in October. 

Guangdong province's patient is a 58-year-old man from Zhaoqing who is hospitalized in critical condition, according to FluTrackers' translation of an official provincial report. 

The three new cases lift the global H7N9 total to 611, according to a case list maintained by FluTrackers.   

Egypt confirms 5 new H5N1 cases 

Egyptian authorities have confirmed five new cases of H5N1 avian flu, continuing an unusual flood of cases in recent weeks, according to a Ministry of Health and Population statement translated and posted today by FluTrackers. 

The cases involve a 34-year-old man in Faiyum governorate, a 36-year-old man in Cairo governorate, a 38-year-old man and a 3-year-old girl from Asyut governorate, and a 27-year-old man from Minya governorate. The 34-year-old is being treated at a Faiyum hospital, while the other four patients have been treated and released, the health ministry said. 

The statement said eight H5N1 patients remain hospitalized in the country. Egypt has now confirmed 69 cases this year, according to a list maintained by FluTrackers. In all of last year the country reported 30 H5N1 cases, according to World Health Organization (WHO) data. The previous high was in 2006, when Egypt had 55 WHO-confirmed cases.

ECDC: Rapid Risk Assessment of avian flu viruses in China

ECDC has published Human infections with avian influenza A viruses in China, new ECDC Rapid Risk Assessment. Click through to download the full document as a PDF. Excerpt from the summary:

In its new Rapid Risk Assessment, ECDC summarises the latest information about human infections with avian influenza A viruses in China. It focuses on A(H7N9) and A(H5N1) and includes other avian influenza A viruses recently identified. It assesses the risk to public health in the EU/EEA countries and to EU/EEA citizens. 

The severe nature of human infections and the persistence of avian influenzas A(H7N9) and A(H5N1) in poultry represents a significant long-term threat to humans, either through zoonotic transmission or potentially through developing pandemic capacity. However, the most likely current scenario for China is that these outbreaks remain zoonotic outbreaks in which the virus is transmitted sporadically to humans in close contact with the animal reservoir, similar to the influenza A(H5N1) situation.   

The recent importation of A(H5N1) from China to Canada and A(H7N9) from China to Malaysia in travellers highlights the possibility of travel-related cases being detected also in Europe. This should be prepared for by the EU Member States. However, sporadic cases imported from China would not alter ECDC’s current risk assessment.   

The A(H7N9) transmission pattern and the continued and increasing transmission of this novel reassortant avian influenza virus capable of causing severe disease in humans remains a cause for concern due to its pandemic potential. While likely human-to-human transmission of A(H7N9) and A(H5N1) in clusters of reported cases has been documented in a few instances, there is no indication of sustained human-to-human transmission. 

The detection of other new avian influenza human cases, namely A(H10N8) and A(H6N1) likely reflects enhanced surveillance activities in China and Taiwan.   

At present, the most immediate threat to EU citizens is to those living in China or visiting the country. It is advised to avoid live-bird markets and contact with live poultry in China.

H6 influenza viruses: Another potential threat

Thanks to Greg Folkers for sending the link to this Journal of Virology report: H6 influenza viruses pose a potential threat to human health. The abstract:

Influenza viruses of the H6 subtype have been isolated from wild and domestic aquatic and terrestrial avian species throughout the world since their first detection in a turkey in Massachusetts, USA, in 1965. Since 1997, H6 viruses with different NA subtypes have been detected frequently in the live poultry markets of southern China. Although sequence information has been gathered over the last few years, the H6 viruses have not been fully biologically characterized. 

To investigate the potential risk posed by H6 viruses to humans, here, we assessed the receptor-binding preference, replication, and transmissibility in mammals of a series of H6 viruses isolated from live poultry markets in southern China from 2008–2011. Among the 257 H6 strains tested, 87 viruses recognized the human-type receptor. Genome sequence analysis of 38 H6 representative viruses revealed 30 different genotypes, indicating that these viruses are actively circulating and reassorting in nature. Thirty-seven of 38 viruses tested in mice replicated efficiently in the lungs and some caused mild disease; none, however, were lethal. 

We also tested the direct contact transmission of 10 H6 viruses in guinea pigs, and found that five viruses did not transmit to the contact animals, three viruses transmitted to one of the three contact animals, and two viruses transmitted to all three contact animals. 

Our study demonstrates that the H6 avian influenza viruses pose a clear threat to human health and emphasizes the need for the continued surveillance and evaluation of the H6 influenza viruses circulating in nature. 

Importance Avian influenza viruses continue to present a challenge to human health. Research and pandemic preparedness have largely focused on the H5 and H7 subtype influenza viruses in recent years. Influenza viruses of the H6 subtype have been isolated from wild and domestic aquatic and terrestrial avian species throughout the world since their first detection in USA, in 1965. 

Since 1997, H6 viruses have been detected frequently in the live poultry markets of southern China, however, the biological characterization of these viruses is very limited. Here, we assessed the receptor-binding preference, replication, and transmissibility in mammals of a series of H6 viruses isolated from live poultry markets in southern China, and found 34% of the viruses are able to bind human-type receptors and some of them are able to transmit efficiently to contact animals. 

Our study demonstrates that the H6 viruses pose a clear threat to human health.

Taiwan: CDC sounds alarm over H6N1 case

Via Taipei Times: CDC sounds alarm over mutating bird flu strain. Excerpt:

Researchers in Taiwan yesterday called on health watchdogs to keep their guard up after a flu virus strain that commonly circulates among chickens was found for the first time in a human being. 

The strain was found in a 20-year-old patient from central Taiwan and although it was of relatively low virulence, it poses a risk if it mixes with other viruses and becomes more dangerous, the researchers said. 

“Our report highlights the continuous need for preparedness for a pandemic of unpredictable and complex avian influenza,” they added. 

Writing in the journal Lancet, a team led by Wu Ho-sheng (吳和生) from the Centers for Disease Control (CDC) reported on the case of a woman who was hospitalized in May with a fever, cough and breathing difficulties. 

The agency first announced the incident in June and the publication in the peer-reviewed journal provides fuller details of its response to the case and a wider assessment of the risks it poses. 

Gene sequencing of a throat swab sample taken from the patient showed that the cause of her symptoms was a local strain of the H6N1 influenza virus, the team reported. 

H6N1 is a subtype of flu found among wild birds and domestic poultry on many continents. 

In Taiwan, a unique genetic lineage of H6N1 has evolved over more than 40 years, previous research has found. 

The local strain has shown the potential to cross-infect lab mammals, but this was the first time it had been linked to infection in a human. 

The sample taken from the woman notably had a so-called G228S mutation in a surface protein called haemagglutinin that helps the virus to latch onto cells in the human host’s upper respiratory tract. 

The unnamed woman recovered after being treated with the anti-viral drug Tamiflu, the study said. 

When, where and how she became infected with the novel virus is unknown.

Media around the world have predictably wrung their hands about this "new threat," but while it's interesting, it seems far from threatening. We have one case, provenance unknown, which responded to Tamiflu. No one else contracted it, and the patient recovered. H6N1 deserves continued surveillance and study, but far more urgent threats confront us.

Human infection with avian influenza A H6N1 virus: an epidemiological analysis

Via The Lancet Respiratory Medicine: Human infection with avian influenza A H6N1 virus: an epidemiological analysis. The abstract:

Background 

Avian influenza A H6N1 virus is one of the most common viruses isolated from wild and domestic avian species, but human infection with this virus has not been previously reported. We report the clinical presentation, contact, and environmental investigations of a patient infected with this virus, and assess the origin and genetic characteristics of the isolated virus. 

Methods 

A 20-year-old woman with an influenza-like illness presented to a hospital with shortness of breath in May, 2013. An unsubtyped influenza A virus was isolated from her throat-swab specimen and was transferred to the Taiwan Centres for Disease Control (CDC) for identification. The medical records were reviewed to assess the clinical presentation. We did a contact and environmental investigation and collected clinical specimens from the case and symptomatic contacts to test for influenza virus. The genomic sequences of the isolated virus were determined and characterised. 

Findings 

The unsubtyped influenza A virus was identified as the H6N1 subtype, based on sequences of the genes encoding haemagglutinin and neuraminidase. The source of infection was not established. Sequence analyses showed that this human isolate was highly homologous to chicken H6N1 viruses in Taiwan and had been generated through interclade reassortment. Notably, the virus had a G228S substitution in the haemagglutinin protein that might increase its affinity for the human α2-6 linked sialic acid receptor. 

Interpretation 

This is the first report of human infection with a wild avian influenza A H6N1 virus. A unique clade of H6N1 viruses with a G228S substitution of haemagglutinin have circulated persistently in poultry in Taiwan. These viruses continue to evolve and accumulate changes, increasing the potential risk of human-to-human transmission. Our report highlights the continuous need for preparedness for a pandemic of unpredictable and complex avian influenza.

I posted about this case when it was first reported last June, and the Lancet paper has renewed interest in it: There are stories today by The Associated Press, The Los Angeles Times, and the BBC.

Taiwan's response to H6N1

Via the Taipei Times: CDC reports H6N1 avian flu infection. After describing the first case and her recovery, the report goes on:

“We tested specimens from the poultry in the two poultry farms near the patient’s home, but found no H6N1 virus,” Council of Agriculture official Chao Parn-hwa (趙磐華) said. 

“H6N1 was first found in Taiwan’s poultry in 1972. As it is not an OIE [World Organization for Animal Health]-reportable disease; no quarantine or culling measures are to be imposed,” Chao added. 

Wu Ho-sheng (吳和生), director of the CDC’s Research and Diagnostic Center, said that the authority started a systematic influenza surveillance project in 1999, testing specimens collected from patients with notifiable communicable diseases, influenza-like illnesses and unexplained pneumonia. 

“With 10,000 to 20,000 specimens each year, the center has to date tested more than 250,000 specimens and isolated 86,000 influenza virus strains. Other than the imported H7N9 strain tested earlier this year, no non-H1/H3 subtypes of influenza A viruses had been detected in humans in Taiwan until this H6N1 case,” Wu said. 

CDC official Chuang Jen-hsiang (莊人祥) said H6N1 is a low-pathogenic avian influenza strain that is commonly found in poultry, and that no human infection has been reported. 

“The genetic sequence of the H6N1 isolate taken from the patient shows that the virus is avian-origin and closely resembles the avian influenza A (H6N1) virus found in poultry,” Chuang said, adding that the CDC has already notified the WHO and countries that have close relations with Taiwan, including the US, China, Japan, South Korea and the EU. 

Wang Ching-ho (王金和), professor of veterinary medicine at National Taiwan University, said all eight gene segments of the H6N1 virus isolate are avian. 

The CDC is not concerned about a widespread poultry-to-human H6N1 infection, Wang said. 

Chao said the bureau has ordered the poultry farm operators to tighten sanitation management. 

The government’s decision to ban the slaughter of live poultry at traditional marketplaces from May 17 will help to protect people from being infected with avian flu viruses, he added.

CIDRAP: Taiwan reports first human H6N1 infection

Via CIDRAP, Lisa Schnirring writes: Taiwan reports first human H6N1 infection. Excerpt:

Health authorities in Taiwan today announce d the first known human infection with H6N1 avian influenza, in a 20-year-old woman who was sick with pneumonia in May and has since recovered. 

The virus was identified at a time when Taiwan officials were on heightened alert for H7N9 illnesses. The woman's novel flu infection first came to the attention of Taiwanese health officials just 2 weeks after the region had identified its first H7N9 case in a man who had recently traveled to China's outbreak area for work. 

The woman started having flu-like symptoms on May 5 and was hospitalized 3 days later after her condition worsened, according to a statement from the Taiwan Centers for Disease Control (Taiwan CDC). She was diagnosed with mild pneumonia, and her illness quickly improved after she was treated with oseltamivir (Tamiflu). 

Tests on her respiratory specimen at the hospital indicated an unsubtypable influenza A virus, and genome sequencing at Taiwan CDC's National Influenza Center found that the virus was a novel avian-origin H6N1 virus. 

The woman was discharged from the hospital on May 11 and has fully recovered. Follow-up serum testing showed an antibody titer of 1:20 on May 24, and a sample collected on Jun 8 showed a 1:40 titer. 

An investigation revealed that the woman works at a breakfast shop, had not been out of the country, and had no exposure to poultry or birds. 

Of 36 close contacts that were tested, 4 had flu-like symptoms, but none tested positive for the H6N1 virus, according to Taiwan CDC. 

Agriculture authorities collected specimens from two poultry farms that were within 1 kilometer of the woman's home, but tests found no H6N1 virus. 

Taiwan CDC said it routinely collects specimens from patients who have flu-like illness or unexplained pneumonia. So far this year about 250,000 specimens have been tested and 86,000 viruses isolated and identified. The imported H7N9 strain and the woman's H6N1 strain are the only non-H1N1 or H3N2 subtypes that have been detected.

This is fascinating: How is it that after centuries of ignoring human beings, not one but three avian flu viruses mutate enough to infect people, at least occasionally? First H5N1, then H7N9, and now H6N1—I'm excluding H1N1, which has been around a lot longer. Is it because we're looking more extensively and intensively? Or has some environmental factor played a role? The sooner we understand how this happened, the sooner we'll understand viruses in general.

First human infection of H6N1 bird flu confirmed in Taiwan

Avian influenza is rolling out new models with amazing speed. Via Xinhua: First human infection of H6N1 bird flu confirmed in Taiwan.

Taiwan's disease control authority on Friday confirmed that the world's first human infection of H6N1 bird flu has been reported on the island, adding that the patient has already recovered. 

The patient was identified as a 20-year-old woman from central Taiwan. She has not left Taiwan recently and has not had any recent contact with birds, according to the authority. 

The authority said a hospital reported on May 20 that an unconfirmed type of flu virus was found in respiratory tract samples taken from the patient, who was initially diagnosed with pneumonia. 

Further testing confirmed the virus to be H6N1, a low-pathogenic avian influenza virus that exists commonly in birds but has never been reported in humans, according to the authority. 

Four of the 36 people the patient has had close contact with have shown flu-like symptoms, although possible H6N1 infections were ruled out by tests. 

No H6N1 virus has been found in samples collected from two poultry breeding sites located close to the patient's home, the authority said, citing testing results from the island's agricultural oversight agency.