A Killer Bomb : Waiting for a Spark!

While sitting on the sofa and watching the devastating footage of earthquake in Pakistan, when SARS broke in we said oh! Poor Chinese! Same to AIDS- it is government's problem, not of us! Now scientists are trying to bring a new agenda, they call it 'Bird Flu'! It may be the headache of poultry farmers. How on earth we should worry about a simple flu, not even human.

Lets see some news all over the world before going to details.

News 1

Kommersant- Russia's daily online

Oct. 19, 2005

Bird Flu Spreads to Tula Village

The actions of unprecedented safety have been taken in Yandovka following the disclosure that the bird flu might have reached that village of Tula Region and approached Moscow.

Yandovka villagers, where over 300 chickens, ducks and geese died in the seven private farms over a few days. The authorities have blocked all access roads and introduced the quarantine.

News 2

October 21, 2005

IN BRIEF/LOS ANGELES COUNTY / LOS ANGELES

Bird-Flu Fears Prompt Discussions at LAX

From Times Staff and Wire Reports

Seventy-five officials from 30 local, federal and state agencies met Thursday to plan what to do if a passenger with a communicable disease arrives at Los Angeles International Airport.

Officials are devising the plan because health officials fear that a deadly strain of bird flu could mutate into a form that could be transmitted among humans.

The 5 1/2 -hour closed-door session helped health, law enforcement and airport authorities develop a plan for how LAX would quarantine arriving passengers for at least 48 hours. The plan is scheduled to be finished next month.

News 3

Thai health experts raise concerns about baby bird flu victim case

13 November

BANGKOK - Thai health authorities have confirmed that an 18- month-old boy has contracted the H5N1 bird flu virus.

Director-General of the Department of Medical Sciences Doctor Paijit Warachit confirmed over the weekend that four known bird flu patients currently undergoing treatment in Thailand.

News 4

Two more bird flu deaths in Indonesia

18 November 05

INDONESIA has confirmed bird flu has killed two more people, a day after China reported its first human cases, including at least one death - menacing signs that the virus is spreading faster as the northern winter flu months near.

The WHO in Jakarta said tests sent to a Hong Kong laboratory came back positive for the H5N1 bird flu virus for a 20-year-old woman and a 16-year-old girl both of them died last week, WHO spokeswoman Sari Setiogi said.

The announcement came a day after China's Health Ministry confirmed the virus killed a poultry worker and sickened a nine-year-old boy, who later recovered in central Hunan province, the official Xinhua News Agency said. The boy's 12-year-old sister, who also died, was recorded as a suspected case.

"This is a psychologically telling moment for a country that has never had bird flu cases in the past in humans," WHO Beijing spokesman Roy Wadia said yesterday. "This will drive home to citizens across the country that this can happen in our own back yards."

Officials have warned a human infection in China is inevitable after the country suffered 11 outbreaks in poultry during the past month, which prompted authorities to destroy millions of birds.

Health experts worry that the virus, which is hard for people to catch, will alter into a form easily passed from person to person, possibly igniting a global flu pandemic that kills millions. So far, most human cases have been traced to contact with infected birds.

So, what do you feel? I think it is pretty much clear that something is going on. Something that can cost life, something that comes from birds, something that can spread like a wild fire and something that is unpredictable. I am talking about Bird Flu. Lets go deeper.

Why all of a sudden are the scientists concerned about the flu?

The answer is biological. We frequently get flu- the human type. Our body has a special defense mechanism called immune system. This immune system knows well about the human flu and many other infectious diseases and fight them accordingly. So, we get sick but eventually recover. But think, if our body defense army does not know a killer virus like the bird flu and have no arms against it, what happens? The virus simply kills. Lets have an example.

The deadly small pox (also a viral disease) is eradicated from the whole world since 1980. So, there is no germ of small pox in the air and no vaccine is given for it since then. Our body is completely unknown to that virus. There are only two places in the world this greatest terror mankind is preserved; the laboratories of Atlanta, USA and

Koltsovo, Russia under stringent army surveillance. Now imagine somehow accidentally some germs leak out or somebody use it as biological weapon- there will no one to tell you what may happen!

So, you may have a query why it did not happen earlier. Yes it happened before but checked promptly. It is only dangerous when it affects human body. Not all bird flu virus affect us, in fact none of them. But when they are modified that is transforming to a new strain, then they can affect human body. The good news is that it is rare and took years after years. But present situation is different. Scientists are getting the evidence that the rare thing happened already, and we are just waiting for a spark.

Should not we have to know about the ticking bomb!

The VIRUS

There are fifteen subtypes of influenza virus known to infect birds, thus providing an extensive reservoir of influenza viruses potentially circulating in bird populations.

The virus can survive, at cool temperatures, in contaminated manure for at least three months. In water, the virus can survive for up to four days at 22 degrees C and more than 30 days at 0 degrees C. For the highly pathogenic form, studies have shown that a single gram of contaminated manure can contain enough virus to infect 1 million birds.

These viruses are highly unstable and have the ability to mutate rapidly, potentially jumping from one animal species to another. Scientists fear the bird flu virus could evolve into a form that can easily spread between people, resulting in an extremely contagious and lethal disease. This could happen if someone already infected with the human flu virus catches the bird flu. The two viruses could recombine inside the victim's body, producing a hybrid that could readily spread from person to person.

To date, all outbreaks of the highly pathogenic form have been caused by influenza A viruses of subtypes H5 and H7.

Of them, H5N1 is of particular concern for several reasons. Why H and N? From a clinical viewpoint, the most significant surface proteins of this virus are hemagglutinin and neuraminidase. The viruses are typed based on these proteins. For example, influenza A (H5N1) expresses hemagglutinin 5 and neuraminidase 1.

H5N1 mutates rapidly and has a documented propensity to acquire genes from viruses infecting other animal species. Its ability to cause severe disease in humans has now been documented on two occasions. In addition, laboratory studies have demonstrated that isolates from this virus have a high pathogenicity and can cause severe disease in humans. Birds that survive infection excrete virus for at least 10 days, orally and in feces, thus facilitating further spread at live poultry markets and by migratory birds.

So, it is clear that bird flu is not the same as SARS (Severe Acute Respiratory Syndrome). Although their symptoms are similar, SARS is caused by completely different viruses. Influenza viruses also are more contagious and cannot be as readily contained as SARS by isolating people who have the infection.

The background history:

The resulting virus likely would be something humans have never been exposed to before. With no immune defenses, the infection could cause devastating illness, such as occurred in the 1918-19 Spanish flu pandemic, which killed an estimated 40 million to 50 million worldwide.

Confirmed instances of avian influenza viruses infecting humans since 1997 include:

1997: In Hong Kong, avian influenza A (H5N1) infected both chickens and humans. This was the first time an avian influenza virus had ever been found to transmit directly from birds to humans. During this outbreak, 18 people were hospitalized and 6 of them died. To control the outbreak, authorities killed about 1.5 million chickens to remove the source of the virus. Scientists determined that the virus spread primarily from birds to humans, though rare person-to-person infection was noted.

1999: In Hong Kong, cases of avian influenza A H9N2 were confirmed in 2 children. Both patients recovered, and no additional cases were confirmed. The evidence suggested that poultry was the source of infection and the main mode of transmission was from bird to human. However, the possibility of person-to-person transmission remained open.

2003: Two cases of avian influenza A (H5N1) infection occurred among members of a Hong Kong family that had traveled to China. One person recovered, the other died. How or where these 2 family members were infected was not determined.

2003: Avian influenza A (H7N7) infections among poultry workers and their families were confirmed in the Netherlands during an outbreak of avian flu among poultry.

More than 80 cases of H7N7 illness were reported and 1 patient died (in a veterinarian who had visited an affected farm). There was evidence of some human-to-human transmission.

2003: H9N2 infection was confirmed in a child in Hong Kong. The child was hospitalized but recovered. Experts agree that another influenza pandemic is inevitable and possibly imminent.

2005: H5N1 strikes again specially in China, Indonesia, Vietnam, Russia. Already it took 64 lives. Scientists are afraid that it is only the beginning.

Most influenza experts also agree that the prompt culling of Hong Kong's entire poultry population in 1997 probably averted a pandemic.

What is the Source?

Migratory waterfowl - most notably wild ducks - are the natural reservoir of avian influenza viruses, and these birds are also the most resistant to infection. Domestic poultry, including chickens and turkeys, are particularly susceptible to epidemics of rapidly fatal influenza.

Direct or indirect contact of domestic flocks with wild migratory waterfowl has been implicated as a frequent cause of epidemics. Live bird markets have also played an important role in the spread of epidemics.

Pathogenicity:

Recent research has shown that viruses of low pathogenicity can, after circulation for sometimes short periods in a poultry population, mutate into highly pathogenic viruses. During a 1983-1984 epidemic in the United States of America, the H5N2 virus initially caused low mortality, but within six months became highly pathogenic, with a mortality approaching 90%. Control of the outbreak required destruction of more than 17 million birds at a cost of nearly US$ 65 million. During a 1999-2001 epidemic in Italy, the H7N1 virus, initially of low pathogenicity, mutated within 9 months to a highly pathogenic form. More than 13 million birds died or were destroyed.

Disease in birds:

The disease in birds has two forms. The first causes mild illness, sometimes expressed only as ruffled feathers or reduced egg production. Of greater concern is the second form, known as "highly pathogenic avian influenza". This form, which was first recognized in Italy in 1878, is extremely contagious in birds and rapidly fatal, with a mortality approaching 100 per cent. Birds can die on the same day that symptoms first appear.

Transmission:

In rural areas, the H5N1 virus is easily spread from farm to farm among domestic poultry through the feces of wild birds. Within a country, the disease spreads easily from farm to farm. Large amount of virus is excreted in bird droppings, contaminating dust and soil. Airborne virus can spread the disease from bird to bird, causing infection when the virus is inhaled. Contaminated equipment, vehicles, feed, cages or clothing- especially shoes - can carry the virus from farm to farm. The virus can also be carried on the feet and bodies of animals, such as rodents, which act as "mechanical vectors" for spreading the disease. Limited evidence suggests that flies can also act as mechanical vectors.

Droppings from infected wild birds can introduce the virus into both commercial and backyard poultry flocks. The risk that infection will be transmitted from wild birds to domestic poultry is greatest where domestic birds roam freely, share a water supply with wild birds, or use a water supply that might become contaminated by droppings from infected wild-bird carriers.

So called "wet" markets, where live birds are sold under crowded and sometimes in unsanitary conditions, can be another source of spread.

So far in this outbreak, human cases have been blamed on direct contact with infected chickens and their droppings. People who catch the virus from birds can pass it on to other humans, although the disease is generally milder in those who caught it from an infected person rather than from birds.

If the virus mutates and combines with a human influenza virus, it could be spread through person-to-person transmission in the same way the ordinary human flu virus is spread.

Consequences Of An Influenza Pandemic :

During the last century, 3 influenza pandemics caused millions of death worldwide, social disruption and profound economic losses. Influenza experts agree that another pandemic is likely to happen. Epidemiological models project that in industrialized countries alone, the next pandemic is likely to result in 57-132 million outpatient visits and 1.0-2.3 million hospitalizations, and 280 000-650 000 deaths over less than 2 years. The impact of the next pandemic is likely to be greatest in developing countries where health care resources are strained and the general population is weakened by poor health and nutrition.

How is it diagnosed?

Patients usually develop symptoms of fever, sore throat, cough and in several of the fatal cases, severe respiratory distress secondary to viral pneumonia. Previously healthy adults and children, and some with chronic medical conditions, were affected.

The presentation of influenza virus infection can vary.

Abrupt onset of illness is typical. Patients usually can give the time the illness began.

Fever may vary widely among patients, with some having low fevers in the 100�F range, and others developing fevers as high as 104�F. Patients may report feeling feverish and a feeling of chill.

Sore throat may be severe and last 3-5 days. The sore throat may be a significant reason why patients seek medical attention.

Muscle pain is a common complaint and range from mild to severe.

Headache is common and usually is severe. Ocular symptoms are observed in some patients and include photophobia, burning sensations, and sometimes pain upon motion.

Rhinitis of varying degrees is present in some patients but generally is not the overriding complaint of patients.

Weakness and severe fatigue may prevent patients from performing their normal activities or work. In some cases they require bed rest.

Cough and other respiratory complaints may initially be minimal but frequently progress as the infection evolves. Patients may complain of a nonproductive cough, cough related chest pain, and respiratory distress. In children, diarrhea may be a feature.

Acute encephalopathy- inflammation of brain has recently been described to be associated with the virus. Clinical features included altered mental status, coma, seizures, and ataxia. Of those having further testing, most had abnormal CSF, MRI and EEG findings.

With these features we should seek for any history of animal contact, specially poultry birds, travel from infectious zones, occupational exposure etc. Besides bird flu at this moment in our country we should also consider following diseases.

Dengue Fever

Infectious Mononucleosis

Japanese Encephalitis

Meningitis

Parainfluenza Virus

Rhinoviruses

Sepsis- Bacterial

Severe Acute Respiratory Syndrome (SARS)

Upper Respiratory Infection by other viruses

Even acute HIV infection

Investigations:

Tests for diagnosing all influenza strains of animals and humans are rapid and reliable. Many laboratories in the WHO global influenza network have the necessary high-security facilities and reagents for performing these tests as well as considerable experience.

Lab Studies:

Findings of standard laboratory studies (eg, CBC count, electrolytes) are nonspecific.

X-ray: to see pneumonia

Lumbar puncture: if encephalitis suspected

For confirmation: Viral culture of nasal, pharyngeal and throat samples.

Other tests: Direct immunofluorescent tests, serological tests

Because of cost, availability, and sensitivity issues, most physicians diagnose influenza on clinical criteria alone. For confirmatory diagnosis, as a Bangladeshi physician it is advised to contact CDC (Center for Disease Control, Atlanta, USA) or WHO directly or through ICDDR'B if there is any epidemic outbreak suspected.

Treatment:

Two new drugs have been marketed recently for treatment of affected human. These are the neuraminidase inhibitors oseltamivir and zanamivir.

Oseltamivir is taken orally (75 mg twice a day), and zanamivir is taken via an inhalation apparatus (10 mg twice a day for 5 days).

To be effective, these new agents must be administered within 40 hours of the onset of symptoms.

The bronchospasm (narrowing of major airway) associated with zanamivir has received attention from national media.

Until more data are available, physicians should not prescribe zanamivir to patients prone to bronchospasm. As far as I know it is not available in Bangladesh.

The virus appears to be resistant to two older generic flu drugs, amantadine and rimantadine. However, the newer flu drugs Tamiflu and Relenza are expected to work - though supplies could run out quickly if an outbreak occurs.

Complications:

  1. Primary influenza pneumonia is characterized by progressive cough, dyspnea, and cyanosis following the initial presentation on the infection. It can progress to a presentation similar to acute respiratory distress syndrome. In the 1918-1919 epidemic, many young adults died of a pneumonia that some experts believe was caused directly by the virus.
  2. Secondary bacterial pneumonia can occur from a number of bacteria (eg, Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae).The most dreaded is staphylococcal pneumonia, which develops 2-3 days following the initial presentation of viral pneumonia. These patients are at risk for hypotension.
  3. Myositis, that is inflammation of muscle is a rare complication.
  4. Myocarditis and pericarditis in heart have been associated with influenza infections.

Prevention:

Vaccine for human:

Currently there is no vaccine, although scientists are working to develop one. However, at least four months would be needed to produce a new vaccine, in significant quantities, capable of conferring protection against a new virus subtype.

But it may not be ready in time to stop a widespread human outbreak, if one occurs.

An available vaccine prototype virus, developed using the 2003 strain of H5N1 (which caused the two human cases in Hong Kong), cannot be used to expedite vaccine development.

Initial analysis of the 2004 virus, conducted by laboratories in the WHO network, indicates that the virus has mutated significantly.

Control measures of the birds:

The most important control measures are rapid destruction ("culling" or "stamping out") of all infected or exposed poultry birds, proper disposal of carcasses, and the quarantining and rigorous disinfection of farms.

Restrictions on the movement of live poultry, both within and between countries, are another important control measure.

Regular shots of flu vaccines already prepared for the farm birds is very much useful.

Stringent sanitary measures on farms can, however, confer some degree of protection.

There is actually no way of controlling the wild birds and it is also totally impractical.

I want to conclude now. Imagine what will happen in Bangladesh if it really comes. We are not prepared now. I anticipate that everybody should understand the fact at least those reading this article. We pray and hope the countries that are already affected, specially China will succeed in this war against the deadly virus and save the world from a pandemic again like they conquered SARS in 2003.

Submitted By:
DR. RENE SUZAN CLAUDE SARKER

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