Human Infection Avian Influenza Virus and its Treatment Prevention and Diagnosis
Meaning of Avian Influenza Virus: Avian influenza generally refers to human infection with
avian influenza. Human infection with bird flu is a human disease caused by the
bird flu virus. Avian influenza virus belongs to influenza A virus. According
to the different pathogenicity of avian influenza virus to chickens and
turkeys, it is divided into three levels:
- High
- Medium
- Low / non-pathogenic
Due to the characteristics of the hemagglutinin structure of
the avian influenza virus, birds are generally infected.
When the virus
regenerates during the replication process, the structure changes and the
ability to infect people is acquired, which may cause the occurrence of human
infection of avian influenza diseases. So far, the subtypes of avian influenza
viruses that can directly infect humans are:
- H5N1
- H7N1
- H7N2
- H7N3
- H7N7
- H9N2
- H7N9 subtypes.
Among them, the highly pathogenic H5N1 subtype and the new
bird flu H7N9 subtype first discovered in humans in March 2013 are of
particular interest, not only causing human casualties, but also damaging the
poultry industry.
English name: Influenza in birds
Nickname: Human avian influenza,
human avian influenza, avian influenza, human infection with highly pathogenic
avian influenza
English alias: Avian-human
influenza
Treatment department: Infectious Diseases
Multiple groups: Old men
Common causes: Bird flu virus
Common symptoms: Influenza-like
symptoms, including fever, cough, and headaches
Infectious: Yes
Way for spreading: Infection by direct
contact with objects or environment contaminated by poultry or its excrement
How to prevent H7N9 Avian Influenza Virus infection in life?
Live poultry market
exposure is a risk factor for human infection with H7N9 avian influenza,
virus-carrying poultry and their excreta. Be careful with them.
Table of Content
- Discovery history and epidemiology
- Clinical manifestations
- Check
- Diagnosis
- Treatment
- Prevention
Discovery history and epidemiology of Avian Influenza Virus
It was isolated from pest chickens in 1878. In 1901, this
"chicken plague pathogen" was called "filtering factor" or
fowl plague virus (FPV). Later, it was discovered that Newcastle disease virus
(NDV) can cause chicken plague-like disease in poultry, which is commonly known
as "chicken plague" in Asia.
To distinguish between the two, the
former is called true chicken fever or European chicken fever virus, and the
latter is called pseudo chicken fever or Asian chicken fever virus.
In 1955,
based on the characteristics of viral particle nuclear protein antigen, FPV was
identified as a member of influenza A virus.
The vast majority do not cause
chicken plague in poultry, even in a silent infection or healthy carrying
state, such as the newly discovered H7N9 avian influenza virus in China in
2013, which basically does not cause disease between poultry.
The H5N1 subtype was first discovered in Hong Kong in 1997 to
directly infect humans.
As of March 2013, a total of 622 cases of human
infection with highly pathogenic H5N1 avian influenza have been reported
worldwide, including 371 deaths.
The cases were distributed in 15 countries,
among which 45 cases were found in our country and 30 died.
The majority of people
infected with H5N1 avian influenza are young people and children. In March
2013, China first discovered a case of human infection with H7N9 avian
influenza.
As of May 1, 2013, 10 provinces (cities) including Shanghai, Anhui,
Jiangsu, Zhejiang, Beijing, Henan, Shandong, Jiangxi, Hunan, and Fujian
reported a total of 127 confirmed cases, including 26 deaths. The majority of
cases are elderly people, more men than women.
Current research has found that the source of human infection
with avian influenza is the birds that carry the virus. The transmission route
still needs to be clear.
The study believes that the main route of human
infection with H5N1 subtype avian influenza is close contact with sick and dead
birds. High-risk behaviors include slaughtering, plucking and processing of
infected birds.
In a few cases, when children play in areas where free-range
poultry frequently occur, feces exposed to poultry are also considered a source
of infection.
Most of the evidence in the current study indicates the existence
of poultry-human transmission, possible environmental (environmental
contamination by poultry waste) -human transmission, and a few unsustainable
human-to-human transmission.
It is currently believed that H7N9 avian influenza
patients are infected through direct contact with items or the environment
contaminated by birds or their excreta.
The cases of human infection with H7N9
avian influenza are still in a sporadic state. Although there have been
individual family aggregation cases, at present, the virus has not been found
to have the ability to spread from person to person.
What are the Clinical Manifestations of Avian Influenza Virus infection?
According to the investigation results of existing human
cases of H7N9 and H5N1 avian influenza, the incubation period is generally
within 7 days.
In the initial stage of the disease, the patient showed
flu-like symptoms, including fever and cough, which may be accompanied by
headache, muscle aches and general malaise. Runny nose, stuffy nose, and sore
throat may also occur.
Symptoms such as chest tightness and dyspnea occur in
some patients when the lung lesions are severe or the disease progresses
rapidly. Respiratory symptoms appear earlier, generally within 1 week after the
onset, and last longer. Some patients still have severe cough and sputum after
1 month of treatment.
Chest tightness, shortness of breath, and dyspnea at the
beginning of the disease often indicate that the lesions in the lungs progress
rapidly and will rapidly develop into severe hypoxia and respiratory failure.
In severe patients, the disease progresses rapidly, and severe pneumonia occurs
mostly in 5 to 7 days.
The body temperature mostly lasts above 39 ° C.
Difficulty breathing may be accompanied by hemoptysis.
It can rapidly progress
to acute respiratory distress syndrome, sepsis and infectivity.
In shock, some
patients may have mediastinal emphysema and pleural effusion.
A considerable
proportion of critically ill patients are combined with other system or organ
damage or failure at the same time, such as heart failure caused by myocardial
injury, individual patients also have gastrointestinal bleeding and stress
ulcers and other digestive system symptoms, and some severe patients have coma and disorders of consciousness.
What is the Examination for Avian Influenza Virus?
The white blood cell level of most people infected with avian
influenza is lower than normal, and the level of lymphocytes is not high or
even reduced.
If the platelet level is reduced, it is necessary to consider
whether there is disseminated intravascular coagulation due to severe
infection. It should be combined with the results of coagulation analysis and
fibrinogen level for comprehensive identification.
Blood biochemical
examinations are mostly creatine kinase, lactate dehydrogenase, aspartate aminotransferase,
alanine aminotransferase increased, C-reactive protein increased, myoglobin may
increase.
Imaging examination revealed that flakes appeared in the
lungs of patients with pneumonia. In severe patients, the lesion progresses
rapidly, showing multiple ground glass shadows of the lungs and lung
consolidation images, and a small amount of pleural effusion can be combined.
When ARDS occurs, the lesions are widely distributed.
The most reliable is still the etiology test. Prior to
antiviral treatment. Conditional medical units collect respiratory specimens
for examination (such as nasopharyngeal secretions, oral gargles, tracheal
aspirates, or respiratory epithelial cells) for viral nucleic acid detection
(real-time fluorescent PCR detection) and viruses separately.
In addition to avian influenza virus infection, human
patients with avian influenza often have bacterial infections or secondary
bacterial infections at an early stage.
After using antimicrobial drugs for a
long time or in large doses and inappropriate use of glucocorticoids, fungal
infections can also be combined. Therefore, sputum culture and respiratory
tract aspirate culture should be carried out multiple times in the clinic to
check the type of bacteria and / or fungi, as well as their sensitive or
drug-resistant types, so as to select antibiotics reasonably in clinical and
guide clinical treatment.
What is the Diagnosis for Avian Influenza Virus?
According to the standards in the "Diagnosis and
Treatment Scheme for Human Infected Avian Influenza (2008 Edition)"
released in May 2008 and the "Diagnosis and Treatment Scheme for Human
Infected Avian Influenza H7N9 (2nd Edition, 2013)" published in April
2013, according to the epidemiology Contact history, clinical manifestations
and laboratory test results can make a diagnosis of human infection with H5N1
or H7N9 avian influenza.
In the case of unknown epidemiological history,
according to clinical manifestations, auxiliary examinations and laboratory
test results, especially the isolation of avian influenza virus from the
patient's respiratory secretion specimen, or positive detection of avian
influenza virus nucleic acid, or dynamic detection Serum avian influenza virus
specific antibody positive conversion or a 4-fold or more increase, can make a
diagnosis of human infection with avian influenza.
Pathogen testing should be used to distinguish it from other
unexplained pneumonias, such as seasonal influenza (including H1N1 influenza),
bacterial pneumonia, severe acute respiratory syndrome (SARS), new coronavirus
pneumonia, adenovirus pneumonia, and chlamydia Pneumonia, mycoplasma pneumonia
and other diseases.
What is the Treatment for Avian Influenza Viral Infection?
Under the conditions of proper isolation, treatments such as
symptomatic maintenance, anti-infection, ensuring tissue oxygen supply,
maintaining organ function, etc. are given.
Symptomatic maintenance mainly includes bed rest, dynamic
monitoring of vital signs, and physical or drug cooling.
Anti-infective
treatment includes anti-viral (such as oseltamivir, zanamivir, paramivir, etc.)
treatment, but emphasizes that the clinical treatment time should be
"early, fast, and accurate."
In particular, antiviral drugs should be
collected from the respiratory tract specimens before use, and should be used
as much as possible within 48 hours of onset.
For clinical cases that require the
use of antiviral drugs, they can also be used after more than 48 hours of
onset.
Ensuring tissue oxygenation is the core of maintaining the
normal function of vital organs in critical and critically ill patients.
It can
be performed by selecting sequential methods such as nasal canal, mouth / nasal
mask, noninvasive ventilation and invasive ventilation.
The specific treatment method should be conducted under the
guidance of a professional doctor to avoid drug abuse and improper operation,
causing drug resistance and delaying the disease.
What is the Prevention of Avian Influenza Virus?
Combining the characteristics of the avian influenza virus
and existing research findings, it is currently believed that the birds
carrying the virus are the main source of infection of human infection with avian
influenza.
It is particularly important to reduce and control the spread of
avian influenza viruses among birds, especially poultry.
With the improvement
of social and economic development level, there is an urgent need to
accelerate the transformation and upgrading of traditional poultry farming and
circulation to modern production methods, from free-range farming to
centralized large-scale farming, slaughtering treatment and scientific
transportation, to improve the cultivation of poultry and livestock 1.
Circulate biological safety levels, thereby reducing the exposure of live or
sick and dead birds to the crowd.
At the same time, we should continue to carry
out health education, advocate and cultivate personal respiratory hygiene and
prevention habits, wash hands frequently, keep the environment clean, and
properly process cooking food.
The health education and sanitation protection
of people at high risk of human infection with bird flu and medical personnel
need to be strengthened. At the same time, we must do well in animal and human
influenza surveillance.
Timely discover animal infections or epidemics, as well
as the state of virus circulation in the environment, and take measures such as
animal immunization, culling and market closure to eliminate the source of
infection and block the spread of virus between birds as soon as possible.
Early detection and early diagnosis of avian influenza patients, timely,
effective and reasonable implementation of case isolation and diagnosis and
treatment.
Virological Surviellance
Do a good job in epidemiological investigation and virological surveillance, continuously improve the scientific understanding of avian
influenza, promptly find clustered cases and virus mutations, and then take
corresponding intervention and response measures.
While doing a good job of scientific prevention and control,
we must also seriously prepare for the pandemic response.
Author's Bio
 |
| Dr. Shawna Reason |
Education: MBBS, MD
Occupation: Medical Doctor / Virologist
Specialization: Medical Science, Micro Biology / Virology, Natural Treatment
Experience: 15 Years as a Medical Practitioner
About Me | Linkedin | Quora Profile | Medium Profile | Twitter
Comments
Post a Comment