With the ending of the dreaded year 2020, and the news of Covid vaccine, people welcomed 2021 with a ray of hope. But the start of year isn’t what most Indians expected.
With the sudden rise in the unexplained deaths of poultry birds in states like Kerala, Madhya Pradesh, Rajasthan, Himachal etc. in the first week of Jan 2021, the centre warned people about the outbreak of bird flu or the Avian Infleunza, as H5N1 and H8N1 virus strains were found from the samples of dead birds.
Before we get the answer to this question, lets understand what is Infleunza? Acc. to the US CDC , Influenza, commonly known as flu, is a contagious respiratory infection, which infects the nose, throat, and sometimes the lungs. It can cause mild to severe illness, and at times can lead to death.
Yes, you heard the last line correctly, as in most cases the flu treats itself, but in some cases its complications can be deadly.
People who have flu often feel some or all of these symptoms (https://bit.ly/3nL3zcd):
- Fever or feeling feverish/chills (not everyone having flu develops fever)
- sore throat
- runny or stuffy nose
- muscle or body aches
- fatigue (tiredness)
- some people may have vomiting and diarrhoea, though this is more common in children than adults.
People at higher risk of developing flu complications include (https://mayocl.in/39xUw9G):
- Young children under age 5, and especially those under 6 months
- Adults older than age 65
- Residents of nursing homes and other long-term care facilities
- Pregnant women and women up to two weeks after giving birth
- People with weakened immune systems
- People who have chronic illnesses, such as asthma, heart disease, kidney disease, liver disease and diabetes
- People who are very obese, with a body mass index (BMI) of 40 or higher
- Acc. to WHO , seasonal influenza kills up to 650,000 people every year. That is why influenza vaccinations are so important, especially to protect young children, older people, pregnant women, or people who have vulnerable immune systems.
The flu generally spreads through tiny droplets which an infected individual exhales from his mouth while coughing, sneezing or talking. These droplets can land directly on the faces of individuals standing nearby that time. Or, it can indirectly infect someone, when they touch a surface on which the droplets have already landed, and then touch their eyes, nose or mouth.
As the person gets infected, he starts showing symptoms generally in 2 days, though this time period can anywhere between 1-4 days.
Serious complications of flu can include bacterial pneumonia, ear infections, sinus infections and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes (https://bit.ly/3oMLAn2).
The best way to prevent a flu till date is the influenza vaccine.
Other precautions include, staying away from infected people, not touching your face, after touching any surface, and frequent handwashing and sanitizing.
TYPES OF INFLUENZA VIRUSES
Acc. to WHO , there are four types of influenza viruses: types A, B, C and D:
- Influenza A viruses infect humans and many different animals. The emergence of a new and very different influenza A virus with the ability infect people and have sustained human to human transmission, can cause an influenza pandemic.
- Influenza B viruses circulates among humans and cause seasonal epidemics. Recent data showed seals also can be infected.
- Influenza C viruses can infect both humans and pigs but infections are generally mild and are rarely reported.
- Influenza D viruses primarily affect cattle and are not known to infect or cause illness in people.
But this is just the starting. Acc. to US CDC, Influenza A viruses are divided into subtypes based on two proteins on the surface of the virus: hemagglutinin (H) and neuraminidase (N).
There are 18 different hemagglutinin subtypes and 11 different neuraminidase subtypes (H1 through H18 and N1 through N11, respectively).
While there are potentially 198 different influenza A subtype combinations, only 131 subtypes have been detected in nature.
Current subtypes of influenza A viruses that routinely circulate in people include: A(H1N1) and A(H3N2). Influenza A subtypes can be further broken down into different genetic “clades” and “sub-clades.
Influenza B viruses are not divided into subtypes, but instead are further classified into two lineages: B/Yamagata and B/Victoria. Similar to influenza A viruses, influenza B viruses can then be further classified into specific clades and sub-clades.
Acc. to WHO, the influenza virus is constantly mutating – essentially putting on ever-changing disguises – to evade our immune systems. When a new virus emerges that can easily infect people and be spread between people, and to which most people have no immunity, it can turn into a pandemic. “Another pandemic caused by a new influenza virus is a certainty. But we do not know when it will happen, what virus strain it will be and how severe the disease will be,” said Dr Wenqing Zhang, the manager of WHO’s Global Influenza Programme. “This uncertainty makes influenza very different to many other pathogens,” she said.
WHAT ARE ZOONOTIC INFLUENZA VIRUS?
Now, certain influenza viruses found in animals, can infect people. These are called Zoonotic Influenza. Acc. to WHO , People can be infected with influenza viruses that are usually circulating in animals, such as avian influenza virus subtypes A(H5N1) and A(H9N2) and swine influenza virus subtypes A(H1N1) and (H3N2). Other species including horses and dogs also have their own varieties of influenza viruses.
Some zoonotic influenza viruses may occasionally infect humans, and can cause diseases in people ranging from mild conjunctivitis to severe pneumonia and death. Usually these human infections of zoonotic influenza are acquired through direct contact with infected animals or contaminated environments, and do not spread quickly between people (https://bit.ly/2XI0gI6).
WHAT IS AVIAN INFLUENZA (BIRD FLU)?
When animal influenza viruses infect their natural animal host, they are named for that host, as in avian influenza viruses, swine influenza viruses, equine influenza viruses, etc. Bird Flu, also called as Avian Influenza, is a viral infection that infects not just birds but also infects humans and other animals.
Avian, swine and other zoonotic influenza infections in humans may cause disease ranging from mild upper respiratory infection (fever and cough) to rapid progression to severe pneumonia, acute respiratory distress syndrome, shock and even death. Gastrointestinal symptoms such as nausea, vomiting and diarrhoea has been reported more frequently in A(H5N1) infection (https://bit.ly/2KjcgwJ).
In many patients infected by A(H5) or A(H7N9) avian influenza viruses, the disease has an aggressive clinical course. Common initial symptoms are high fever and cough followed by symptoms of lower respiratory tract involvement including dyspnoea or difficulty breathing. Upper respiratory tract symptoms such as sore throat or coryza are less common. Other symptoms such as diarrhoea, vomiting, abdominal pain, bleeding from the nose or gums, encephalitis, and chest pain have also been reported in the clinical course of some patients. Complications of infection include severe pneumonia, hypoxemic respiratory failure, multi-organ dysfunction, septic shock, and secondary bacterial and fungal infections (https://bit.ly/2KjcgwJ).
In term of risk factors for human infections (https://bit.ly/2KjcgwJ):
- for avian influenza viruses, the primary risk factor for human infection appears to be direct or indirect exposure to infected live or dead poultry or contaminated environments, such as live bird markets. Slaughtering, defeathering, handling carcasses of infected poultry, and preparing poultry for consumption, especially in household settings, are also likely to be risk factors. There is no evidence to suggest that the A(H5), A(H7N9) or other avian influenza viruses can be transmitted to humans through properly prepared poultry or eggs. A few influenza A(H5N1) human cases have been linked to consumption of dishes made with raw, contaminated poultry blood.
- for swine influenza viruses, risk factors reported for most human cases includes close proximity to infected pigs or visiting locations where pigs are exhibited, but some limited human-to-human transmission has occurred.
H5N1 is the most common type of avian influenza or bird flu.
Acc. to WHO report, the H5N1 was first reported during an outbreak in poultry in Hong Kong, in 1997. Since 2003, this avian virus has spread from Asia to Europe and Africa, and has become endemic in poultry populations in some countries. Outbreaks have resulted in millions of poultry infections, several hundred human cases, and many human deaths (https://bit.ly/2LYOwyE).
Infected birds shed flu virus in their saliva, nasal secretions, and faeces (droppings). Susceptible birds become infected when they have contact with contaminated excretions or surfaces that are contaminated with excretions (https://bit.ly/2XGYirC).
CAN WE EAT EGGS & CHICKEN DURING BIRD FLU?
Acc. to healthline , consuming properly cooked poultry or eggs from infected birds doesn’t transmit the bird flu, but eggs should never be served runny. Meat is considered safe if it has been cooked to an internal temperature of app. 74deg C.
Acc. to a report by All India Institute of Medical Sciences (AIIMS) , poultry and poultry products can be prepared and consumed as usual, with no fear of acquiring infection with the avian flu virus. One should continue to follow good hygienic and cooking practices. The virus is destroyed at a temperature of 70deg C for 30 minutes.
After handling poultry and eggs, one should wash hands and other exposed parts with soap and water.
Acc. to WHO, cooking of poultry (e.g. chicken, ducks, geese, turkeys and guinea-fowl) at or above 70deg C throughout the product, so that absolutely no meat remains raw and red, is a safe measure to kill the H5N1 virus in areas with outbreaks in poultry.
Highly pathogenic avian influenza virus can be found inside and on the surface of eggs laid by infected birds. Although sick birds will normally stop producing eggs, eggs laid in the early phase of the disease could contain viruses in the egg-white and yolk as well as on the surface of the shell.
Proper cooking inactivates the virus present inside the eggs. Pasteurization used by industry for liquid egg products is also effective in inactivating the virus.
Eggs from areas with outbreaks in poultry should not be consumed raw or partially cooked. To date, there is no epidemiological evidence to suggest that people have been infected with avian influenza by consumption of eggs or egg products (https://bit.ly/2Kk0ulV).
The above recommendations from the leading bodies of the world have made it clear that eating chicken and eggs, when properly cooked (over 70deg C for 30min), is absolutely safe, during the bird flu.