H7N9 Bird Flu Drug Resistance a Concern

Drug resistance has been detected in patients infected with the new bird flu that has emerged in China, say doctors.  The H7N9 virus became resistant to Tamiflu in three out of 14 patients treated with antiviral drugs at Shanghai Public Health Clinical Centre.

The researchers said resistance emerged with "apparent ease" and was "concerning".  There have been no new cases of the infection for more than two weeks. Resistance.  Doctors analysed the virus in 14 patients. All had pneumonia and half needed ventilation to keep them alive.

Treatment with antivirals reduced levels of H7N9 in most patients and led to an improvement in symptoms.  Yet the treatment failed in three patients. Genetic testing of the virus in these patients showed it had acquired the mutations needed to resist the drugs.  The doctors believe that in at least one patient the emergence of resistance was a direct consequence of treatment with Tamiflu.
Such antiviral drugs are the only way of treating the infection.

The researchers said: "The apparent ease with which antiviral resistance emerges in H7N9 viruses is concerning, it needs to be closely monitored and considered in future pandemic response plans."
There have been 131 confirmed cases and 36 deaths since the virus was first reported early this year.
However, the most recent case reported was on 8 May. Efforts to close poultry markets are thought to have significantly reduced the spread of the virus.
 
By James Gallagher Health and science reporter, BBC News
Sourced from www.bbc.com 

Researchers have reported the first case of human-to-human transmission of the new strain of bird flu that has emerged in China.

The British Medical Journal said a 32-year-old woman was infected after caring for her father. Both later died.  Until now there had been no evidence of anyone catching the H7N9 virus other than after direct contact with birds.  But experts stressed it does not mean the virus has developed the ability to spread easily between humans.

By 30 June there had been 133 cases of H7N9 bird flu reported in eastern China and 43 deaths.
Most people had visited live poultry markets or had close contact with live poultry in the week or two before they became ill.

Intensive care
Yet researchers found that the 32-year-old woman had become infected in March after caring for her 60-year-old father in hospital.  Unlike her father - who had visited a poultry market in the week before falling ill - she had no known exposure to live poultry but fell ill six days after her last contact with him.
Both died in intensive care of multiple organ failure.

Tests on the virus taken from both patients showed the strains were almost genetically identical, which supports the theory that the daughter was infected directly from her father rather than another source.
Public health officials tested 43 close contacts of the patients but all tested negative for H7N9, suggesting the ability of the virus to spread was limited.

The researchers said that while there was no evidence to suggest the virus had gained the ability to spread from person to person efficiently, this was the first case of a "probable transmission" from human to human.

Strong warning sign
 
"Our findings reinforce that the novel virus possesses the potential for pandemic spread," they concluded.  Dr James Rudge, of the London School of Hygiene and Tropical Medicine, said that limited transmission between humans is not surprising and has been seen before in other bird flu viruses, such as H5N1.  He added: "It would be a worry if we start to see longer chains of transmission between people, when one person infects someone else, who in turn infects more people, and so on.  "And particularly if each infected case goes on to infect, on average, more than one other person, this would be a strong warning sign that we might be in the early stages of an epidemic".

An accompanying editorial in the BMJ, co-authored by Dr Rudge, concluded that while this study might not suggest that H7N9 is any closer to delivering the next pandemic, "it does provide a timely reminder of the need to remain extremely vigilant".

Sourced from www.bbc.com

Frequently Asked Questions on human infection with influenza A(H7N9) virus, China

Update as of 3 April 2013

1. What is the influenza A(H7N9) virus?

Influenza A H7 viruses are a group of influenza viruses that normally circulate among birds. The influenza A(H7N9) virus is one subgroup among the larger group of H7 viruses. Although some H7 viruses (H7N2, H7N3 and H7N7) have occasionally been found to infect humans, no human infections with H7N9 viruses have been reported until recent reports from China.

2. What are the main symptoms of human infection with influenza A(H7N9) virus?

Thus far, patients with this infection have had severe pneumonia. Symptoms include fever, cough and shortness of breath. However, information is still limited about the full spectrum of disease that infection with influenza A(H7N9) virus might cause.

3. How many human cases of influenza A(H7N9) virus have been reported in China to date?

As of 3 April 2013, seven laboratory-confirmed cases have been detected in China. Details of the most current information on cases can be found in Disease Outbreak News.

4. Why is this virus infecting humans now?

We do not know the answer to this question yet, because we do not know the source of exposure for these human infections. However, analysis of the genes of these viruses suggests that although they have evolved from avian (bird) viruses, they show signs of adaption to growth in mammalian species. These adaptations include an ability to bind to mammalian cells, and to grow at temperatures close to the normal body temperature of mammals (which is lower than that of birds).

5. What is known about previous human infections with H7 influenza viruses globally?

From 1996 to 2012, human infections with H7 influenza viruses (H7N2, H7N3, and H7N7) were reported in Netherlands, Italy, Canada, USA, Mexico and the United Kingdom. Most of these infections occurred in association with poultry outbreaks. The infections mainly resulted in conjunctivitis and mild upper respiratory symptoms, with the exception of one death, which occurred in the Netherlands. Until now, no human infections with H7 influenza viruses have been reported in China.

6. Is the influenza A(H7N9) virus different from influenza A(H1N1) and A(H5N1) viruses?

Yes. All three viruses are influenza A viruses but they are distinct from each other. H7N9 and H5N1 are considered animal influenza viruses that sometimes infect people. H1N1 viruses can be divided into those that normally infect people and those that normally infect animals.

7. How did people become infected with the influenza A(H7N9) virus?

Some of the confirmed cases had contact with animals or with an animal environment but the virus has not thus far been found in animals. It is not yet known how these persons became infected. The possibility of animal-to-human transmission is being investigated, as is the possibility of person-to-person transmission.

8. How can infection with influenza A(H7N9) virus be prevented?

Although both the source of infection and the mode of transmission are uncertain, it is prudent to follow basic hygienic practices to prevent infection. They include hand and respiratory hygiene and food safety measures.

Hand hygiene:
• Wash your hands before, during, and after you prepare food; before you eat; after you use the toilet; after handling animals or animal waste; when your hands are dirty; and when providing care when someone in your home is sick. Hand hygiene will also prevent the transmission of infections to yourself (from touching contaminated surfaces) and in hospitals to patients, health care workers and others.
• Wash your hands with soap and running water when visibly dirty; if not visibly dirty, wash your hands with soap and water or use an alcohol-based hand cleanser.

Respiratory hygiene:
• Cover your mouth and nose with a medical mask, tissue, or a sleeve or flexed elbow when coughing or sneezing; throw the used tissue into a closed bin immediately after use; perform hand hygiene after contact with respiratory secretions.

9. Is it safe to eat meat, i.e. poultry and pork products?

Although we do not yet know the mode of transmission, it is prudent to follow basic principles of hygienic food preparation, as follows: Diseased animals should not be eaten. Otherwise, it is safe to eat properly prepared and cooked meat. Because influenza viruses are inactivated by sufficient heating, normal temperatures used for cooking (such that food reaches 70°C in all parts— "piping" hot — no "pink" parts) will kill the virus. In areas experiencing outbreaks, meat products can be safely consumed provided that these items are properly cooked and properly handled during food preparation. The consumption of raw meat and uncooked blood-based dishes is a high-risk practice and is discouraged. Always keep raw meat separate from cooked or ready-to-eat foods to avoid contamination. Do not use the same chopping board or the same knife for raw meat and other foods. Do not handle both raw and cooked foods without washing your hands in between and do not place cooked meat back on the same plate or surface it was on before cooking. Do not use raw or soft-boiled eggs in food preparations that will not be heat treated or cooked. After handling raw meat, wash your hands thoroughly with soap and water. Wash and disinfect all surfaces and utensils that have been in contact with raw meat.

10. Is there a vaccine for the influenza A(H7N9) virus?

No vaccine for the prevention of influenza A(H7N9) infections is currently available. However, viruses have already been isolated and characterized from the initial cases. The first step in development of a vaccine is the selection of candidate viruses that could go into a vaccine. WHO, in collaboration with partners, will continue to characterize available influenza A(H7N9) viruses to identify the best candidate viruses. These candidate vaccine viruses can then be used for the manufacture of vaccine if this step becomes necessary.

11. Does treatment exist for influenza A(H7N9) infection?

Laboratory testing conducted in China has shown that the influenza A(H7N9) viruses are sensitive to the anti-influenza drugs known as neuraminidase inhibitors (oseltamivir and zanamivir). When these drugs are given early in the course of illness, they have been found to be effective against seasonal influenza virus and influenza A(H5N1) virus infection. However, at this time, there is no experience with the use of these drugs for the treatment of H7N9 infection.

12. Is the general population at risk from the influenza A(H7N9) virus?

We do not yet know enough about these infections to determine whether there is a significant risk of community spread. This possibility is the subject of epidemiological investigations that are now taking place.

13. Are health care workers at risk from the influenza A(H7N9) influenza virus?

Health care workers often come into contact with patients with infectious diseases. Therefore, WHO recommends that appropriate infection prevention and control measures be consistently applied in health care settings, and that the health status of health care workers be closely monitored. Together with standard precautions, health care workers caring for those suspected or confirmed to have influenza A(H7N9) infection should use additional precautions (http://www.who.int/csr/resources/publications/swineflu/WHO_CDS_EPR_2007_6/en/index.html).

14. What investigations have begun?

Local and national health authorities are taking the following measures, among others:
• Enhanced surveillance for pneumonia cases of unknown origin to ensure early detection and laboratory confirmation of new cases;
• Epidemiological investigation, including assessment of suspected cases and contacts of known cases;
• Close collaboration with animal health authorities to determine the source of the infection.

15. Does this influenza virus pose a pandemic threat?

Any animal influenza virus that develops the ability to infect people is a theoretical risk to cause a pandemic. However, whether the influenza A(H7N9) virus could actually cause a pandemic is unknown. Other animal influenza viruses that have been found to occasionally infect people have not gone on to cause a pandemic.

16. Is it safe to travel to China?

The number of cases identified in China is very low. WHO does not advise the application of any travel measures with respect to visitors to China nor to persons leaving China.

17. Are Chinese products safe?

There is no evidence to link the current cases with any Chinese products. WHO advises against any restrictions to trade at this time. 

Sourced from the WHO (World Health Organization) web site.

China: Four more infected with H7N9 bird flu

 

 H7N9 is a form of bird flu

A further four cases of a bird flu virus not previously seen in humans have been reported by authorities in China. Three women aged 32, 45 and 48, and an 83-year-old man were diagnosed between 19 and 21 March and are critically ill.  There have now been seven confirmed cases of the H7N9 virus, the World Health Organization said. Two people have died.  But the WHO says there is no evidence of human-to-human transmission.  However more than 160 people who have had contact with the individuals are being closely monitored.  So far, none has developed symptoms.

The latest cases were seen in the Jiangsu province while the earlier cases were in the Shanghai and Anhui provinces.  Two contacts of one of the Shanghai cases who developed symptoms are being retrospectively investigated.  One died and the other recovered, but as yet there has been no laboratory confirmation of whether they were infected with H7N9.

Hygiene measures

The Chinese government has increased disease surveillance, infection prevention and control and communication between human and animal health and industry sectors.

" By identifying the source of infection measures can be taken to reduce human exposure”  

 Dr John McCauley MRC National Institute for Medical Research

It has advised the population to maintain good personal hygiene, including frequent hand-washing and avoiding direct contact with sick or dead animals.  The WHO is not recommending any travel or trade restrictions.  Dr John McCauley, Director of WHO Collaborating Centre on Influenza at the MRC National Institute for Medical Research, said: "The virus belongs to the A(H7N9) sub-type, a sub-type that has not previously infected humans, and has emerged from the reservoir of avian influenza viruses.
 "It is not known how the virus was transmitted.  By identifying the source of infection, measures can be taken to reduce human exposure".  "The Chinese Center for Disease Control and Prevention is investigating whether there has been any human-to-human transmission tests suggest the virus could be treated with the anti-influenza drugs Tamiflu and Relenza.

Sourced from the BBC web site.
www.bbc.co.uk

Tamiflu-resistant swine flu spreads 'between patients'

Health officials say a Tamiflu-resistant strain of swine flu has spread between hospital patients.

 

Five patients on a unit treating people with severe underlying health conditions at the University Hospital of Wales, Cardiff, were infected.  Three appear to have acquired the infection in hospital.
They are thought to be the first confirmed cases of person-to-person transmission of a Tamiflu-resistant strain in the world.  There have been several dozen reports around the world of people developing resistance to Tamiflu while taking the drug - but they have not passed on the strain to others.
Just one possible case of person-to-person transmission of a resistant strain has been recorded - between two people at a US summer camp - and this has never been confirmed.

Two of the University Hospital of Wales patients have recovered and have been discharged from hospital; one is in critical care and two are being treated on the ward.  The health officials stressed there was no risk to anyone else.  They said tests were being carried out to confirm exactly what happened.
The UK has bought enough doses of Tamiflu, which can shorten the duration of swine flu and reduce the risk of complications, for half the population.

Serious concern

So any spread of a Tamiflu-resistant strain of the illness is a serious public health concern.
The H1N1 virus has been remarkably stable since it emerged in April, but virologists had been half expecting new resistant strains to emerge.  Dr Roland Salmon, director of the National Public Health Service for Wales' Communicable Disease Surveillance Centre, said: "The emergence of influenza A viruses that are resistant to Tamiflu is not unexpected in patients with serious underlying conditions and suppressed immune systems, who still test positive for the virus despite treatment.
"In this case, the resistant strain of swine flu does not appear to be any more severe than the swine flu virus that has been circulating since April."  Dr Tony Jewell, Chief Medical Officer for Wales, said: "We know that people with suppressed immune systems are more susceptible to the swine flu virus, which is why they are a priority group under the first phase of the vaccination programme in Wales which is progressing at pace.  "We have stringent processes in place for monitoring for antiviral resistance in the UK so that we can spot resistance early and the causes can be investigated and the cases managed.
"Identifying these cases shows that our systems are working so patients should be reassured.
"Treatment with Tamiflu is still appropriate for swine flu and people should continue to take Tamiflu when they are prescribed it.  "It's also important that good hygiene practices are followed to further prevent the spread of the virus."

Professor Peter Openshaw, a respiratory physician at Imperial College London, said of the spread: "It's not surprising that this has happened, indeed it has always been anticipated".  Dr Ronald Cutler, deputy director of biomedical science at Queen Mary, University of London, said: "Shortening the time taken to produce new vaccines and improving the methods to control and treat the disease while vaccines are being made would be a way forward".  On Thursday it was announced that more than three million healthy children under five across the UK will be offered the swine flu jab.  Figures released on Thursday showed an estimated 53,000 new cases of swine flu in England in the last week, down from 64,000 in the week before.  In Scotland, the figure was 21,200, down from about 21,500 in the previous seven days.
The rate of flu-like illnesses diagnosed by GPs in Wales dropped to 36 cases for every 100,000 people from 65.8 the previous week.

By Fergus Walsh
Health correspondent, BBC News

DRUG RESISTANT FLU WARNING

Australian experts are concerned about the threat of a new type of drug-resistant pandemic flu that is circulating in the population at large.  The swine flu strain has learned how to dodge the antiviral Tamiflu and, though rare, is emerging outside of hospitals.  The team who have studied it say the virus is "fitter" than other drug-resistant strains and the world should be on alert for outbreaks.

UK experts say they have seen a handful of similar cases.  The UK's Health Protection Agency said it would be closely monitoring the situation.  The Australian investigators presented their findings at a meeting on major infectious diseases.

Swine flu

• H1N1 caused a swine flu pandemic (an extensive outbreak in many countries) in 2009 infecting a fifth of the population
• Many people now have some immunity to H1N1 as a result of this exposure
• Vaccines are available that can stop H1N1 infections
• Some people - the sick, elderly, young infants and pregnant women - are at particular risk of complications of they catch H1N1
• Antiviral drugs like Tamiflu can lessen the severity of symptoms in those who catch H1N1

Experts at the Annual Scientific Meeting of the Australasian Society for Infectious Diseases heard how the 'H1N1pdm09' swine flu virus is still sensitive to another antiviral drug Relenza (zanamivir).

But Tamiflu (oseltamivir) is now powerless against the strain that has been found in people in the community rather than sick patients with serious underlying conditions and weak immune systems.
Vaccines can prevent infection occurring in the first place.

Lead investigator Dr Aeron Hurt, from the World Health Organization Collaborating Centre for Reference and Research on Influenza in Melbourne, said: "The greatest concern is that these resistant viruses could spread globally, similar to that seen in 2008 when the former seasonal H1N1 virus developed oseltamivir resistance and spread worldwide in less than 12 months."
The new strain that they have been examining is emerging among people who have never been treated with Tamiflu, suggesting it is very good at spreading from person to person.
Dr Hurt says animal studies by his team confirm this.  Although the Tamiflu-resistant strain is still relatively rare, affecting about 2% of people with swine flu in the Australian population that they studied, Dr Hurt is concerned that it has the potential to turn global.  Similar resistant strains have been detected in Europe but at this stage only on an ad hoc basis, says Dr Hurt.  "The widespread transmission and circulation of oseltamivir-resistant H1N1pdm09 viruses remains a risk in the future.  "Close monitoring of resistant viruses in both treated and community patients remains important."

Pandemic potential In the UK, the HPA has recorded eight cases of oseltamivir-resistant H1N1pdm09 in the community setting.  The HPA's head of flu surveillance Dr Richard Pebody said: "While the frequency of oseltamivir resistance in community settings has increased slightly since the 2009-10 pandemic from 1-2% in the 2012/13 flu season, rates of detection remain low."  Swine flu (H1N1) infected a fifth of people during the first year of the pandemic in 2009, data suggest.
It is thought the virus killed 200,000 people globally.  Although the pandemic has been declared by officials as over, the virus is still circulating.  During the pandemic, the H1N1 virus crowded out other influenza viruses to become the dominant virus. This is no longer the case. Many countries are reporting a mix of influenza viruses.

Sourced from www.bbc.com