Wednesday, February 08, 2006

Bird Flu Outbreak - Iraq

I've meant to write about bird flu for some time now. When the outbreak in Turkey started in January I had a renewed impetus however my schedule has been all enveloping since the beginning of the year. Because of it's importance both in terms of human health as well as potential impacts on wild bird populations I will devote some time to this topic. This is a significant departure to my usual posts on Iraqi natural history.

With two confirmed deaths, several more reported including one from outside of the Kurdish region there is sufficient evidence that certain precautionary measures should be taken including the slaughter of flocks in areas where bird or human infections have been confirmed and people changing behaviors to limit contact with domestic or wild birds such as the use of a mask when tending flocks in areas where no cull has been ordered and stopping all activities like hunting where a person might handle dead birds.

The large scale cull of poultry will cause significant hardship for those who rely on small subsistence flocks of poultry for food. It will also put a strain on the commercial poultry and egg producers.

The main message is to avoid close contact with domestic or wild birds. Most cases to date of Avian Influenza H5N1 have been associated with this risk factor, especially handling birds that are sick or dead. I'll pull together as much useful information as I can for those on the ground. Worldwide there has been no evidence of widespread person-to-person contact. In January the human disease broke out of East and Southeast Asia when human cases started to be reported from Turkey. Several viral mutations noted in the Turkish outbreak are cause for concern and might make the virus more adapted to humans.

I don't claim to be a world expert on bird flu, however my civilian job involves keeping an eye on emerging infectious diseases and how they could potentially affect human health. I write this only to note that keeping an eye on these types of diseases are part of my job and I have closely followed the sporadic outbreaks since 1997 when the first cases of Avian flu were identified in Hong Kong. I wrote my first threat assessment 8 years ago.
All opinions expressed are mine not those of the the Department of Defense or any other agency and are base solely on open source material.

If H5N1 were to remain static as it exists today, most people would have little or no reason to be concerned about a virus that spreads from bird to people less than 200 times in the last 9 years out of tens of millions of potential contacts during that period. If it remains the same, bird flu will be a rare disease in humans that causes huge agricultural losses and has a significant impact on some wild bird species. We can pray that this happens, however we cannot afford to assume it. Bird Flu today is simply a potential source of the next Influenza pandemic that is currently causing massive problems among poultry.

Avian Influenza Viruses are common pathogens in a variety of bird species including domestic birds. Humans with close contact with infected birds very rarely were infected and the result was often a mild disease like conjunctivitis.

In 1997 something alarming happened that told the world there was a potential problem with global implications. Avian Influenza viruses in the H5 subgroup (named after a surface protein) were known to cause mild disease in poultry (ruffled feathers, decreased egg production). In March 1997, in Hong Kong, one particular strain designated H5N1 broke out in a new and lethal form in several farms involving several thousand birds. The first H5N1 Avian Flu Virus actually was first isolated in Scotland in 1959, the first Asian isolate was in Guangdong Province, China in 1996. Chickens with the new Highly Pathogenic H5N1 had a mortality rate approaching 100%. More alarming was that 18 people were infected with this highly pathogenic form, of whom 6 patients died.

All the dots were not connected until August of 1997 after labs subtyped the virus from a human case and found it closely related to those from the bird outbreak. The Hong Kong government considered the single case in May as an isolated case because no other H5N1 cases in humans had been reported during the summer. As a precaution the government increased influenza surveillence and began testing suspected Influenza cases.

In November, after a 6 month hiatus, H5N1 reappeared with a single case. The first two weeks of December brought 6 confirmed cases, then 7 more in the next few weeks. There was a fear that because the normal Hong Kong Flu season was starting there was a potential for the bird flu virus to recombine with a human flu virus in a patient with both infections to produce a more transmissible version of bird flu. A serious concern was that most patients died of a primary viral pneumonia and had no underlying condition or disease that should make them more susceptible to a respiratory virus. Most cases of pneumonia in Influenza patients are caused by a secondary infection caused by bacteria. The secondary infection can often be treated with antibiotics, a primary viral infection cannot be treated with antibiotics. The few children who were infected had mortality rate of around 20% while those over 17 years of age approached 60%. Most cases reported close contact, at farm or market, with poultry in the 24 hours prior to the onset of symptoms.

This set off alarm bells in the places like the World Health Organization and The Centers for Disease Control. In the last century the emergence of a novel Influenza virus has caused several pandemics of varying power. The one that everyone was thinking about was the Influenza Pandemic of 1918 to 1920. Worldwide an estimated 20 to 40 million people died, no one really knows for sure but it may have been much higher with many cases in the developing world. In the US a new contagious disease with a high case fatality rate is of concern, when it is Influenza there is a potential for a global epidemic or pandemic. The good news was that there was little evidence of the nightmare scenario, namely that the disease was spreading person to person through microscopic droplets containing the virus that get suspended in the air when a person coughs or sneezes. The bad news is that Influenza can rapidly mutate and there was a potential for a mutation that allowed efficient person to person spread.

In December 1997 someone in Hong Kong was thinking clearly and ordered something drastic and apparently effective. In 3 days all of Hong Kong's domestic poultry (chickens, ducks, geese, turkeys) were slaughtered. It ended up being 1.6 million birds. The outbreak was contained with no further infections of H5N1. Many believed the world dodged a bullet because there was evidence that the virus was mutating. Hong Kong may have been the best place for the outbreak to have happened. It combined a limited geographic area with access to modern medicine and perhaps most importantly a government that jumped on the problem once it was identified and acted rationally and decisively. The warning of Hong Kong 1997 was that it took a long time to identify what was happening.

I remember attending the International Conference on Emerging Infectious Disease in Atlanta in 1998. At this inaugural meeting of physicians, researchers, and government officials concerned with emerging diseases I heard about the H5N1 outbreak from some scientists from Hong Kong. The mass cull of all of Hong Kong's birds had happened three months earlier. It appeared that the outbreak had been stopped. There was more movement on preparing for an Influenza pandemic including better surveillance mechanisms to try to cut the gap seen in Hong Kong because their labs couldn't type the virus. I think in many people's mind was the idea that somewhere in East Asia H5N1 or some other virus circulating at low levels would break out and start another human epidemic. Next time, I thought, we might not be so lucky, the government might not be so quick or eager to act. I thought interior China would be a good place to demonstrate the statement "How bad can it get before anyone notices". A local government might have a number of reasons to conceal the beginning of an epidemic, the national government might also have their reasons.

H5N1 disappeared from the scene only to emerge again in Hong Kong in 2003 in a family that had recently travelled to southern China. Everyone suspected H5N1 was still circulating somewhere on the mainland. In 2004 cases began to pop up in Vietnam. A gigantic epidemic was in progress among domestic birds with hundreds of outbreaks in the country. During 2004 and 2004 outbreaks of H5N1 showed up in Cambodia, Thailand, China and Indonesia.

Migratory birds have been implicated in the spread of the virus. Most species that have been infected either breed near water or farmland close to human habitation, scavenge near farms like magpies and crows or are kept in captivity like falcons and some songbirds. Some people argue that wild birds are a small part of the story with movements of domestic poultry as the biggest culprit. High amounts of the virus are shed in the feces and may be a mechanism that domestic birds are infected by wild ones and perhaps, more likely, vice versa. There is some evidence that H5N1 is primarily an infection of the gastrointestinal tract in birds. There has been at least 1 human case where there were no respiratory symptoms, only severe diarrhea.

Until January of 2006, Human cases of Bird Flu were confined to East and Southeast Asia. That changed with an outbreak in Turkey that started in January 2006. A widespread epidemic among poultry that had been brewing for several months led to over 20 reported human cases in the space of 2 weeks with 4 deaths. Only 12 cases have been confirmed by the WHO lab. Turkey apparently arrested the epidemic in humans with a massive cull of over 10 million domestic birds. An outbreak of another strain of Avian Influenza in the Netherlands in 2003 resulted in a monster cull of 30 million birds. All but 1 of 53 reported outbreaks in Turkey were in backyard flocks. There was a single outbreak in a commercial flock. The lessons of both Hong Kong and Turkey should be clear. The way to control bird flu is to take the extreme measure of killing all poultry in the outbreak area.

Current Situation in Iraq
In January the first human case of Avian Influenza H5N1 appeared in the Kurdish area of northern Iraq near the city of Suleimaniyah. This was the first instance of bird flu appearing in humans before disease had been reported in birds. Usually birds are the sentinels. In Hong Kong flocks of hundreds of birds suddenly died. Some confusion followed as the government announced that the death was not caused by bird flu. They may have just been buying time. The doctors thought otherwise and sent a sample to the US Naval Medical Research Unit in Cairo. The lab came up with a positive test result for H5N1 and a WHO affiliated lab later confirmed the result. The initial case's 39 year old uncle was later confirmed as the second case. He died on January 27th, 9 days after falling ill. Both cases lived in the same house and were exposed to sick birds. Two outbreaks were officially reported from the area involving 450 dead birds in one flock and 200 in another. Another 2500 birds were reported destroyed in the two flocks with H5 Avian Influenza. The report also speaks of "huge numbers of birds" killed in the area near the Turkish border after Turkey reported bird flu in their border area. Iran reportedly also culled flocks within 15km of the Turkish border. In Iraq there are innumerable backyard flocks of chickens, Turkeys, Ducks and Geese - all which have been affected in other outbreaks and could transmit the disease to humans under the right conditions.

Soon after, there were reports of bird cases in the southern province of Missan near Amara. Amara is near the southern marshes and several hundred miles south of Suleimaniyah. Some have theorized that the birds may have aquired the infection from migrating birds wintering in the marshes. Two pigeons tested for an H5 subtype avian influenza which initiated a cull of almost 1000 birds. There was a report of a death of a young pigeon seller, however, as far as I am aware all human samples from this area have tested negative for H5N1.

Turkey had complained for almost a month that countries surrounding them were ignoring bird flu, even while it raged mere miles from its international borders with countries like Iraq, Iran, Syria and Azerbaijan. The outbreak in Iraq proved their point.

After the first cases were announced a large cull started in the villages surrounding the human cases. As of February 19th the Iraqi Ministry of health reported that 1.5 million poultry have been killed in 2 provinces with over 500 people involve in the effort to contain bird flu. There are over 20 suspected human cases, though only two have been confirmed.

In the last three weeks over a dozen additional countries have reported H5N1 cases in birds. In Nigeria it has been in Chickens, in Europe and Iran it has been in wild waterfowl. As cases proliferate the danger of further human cases also increases. The real danger is that the virus mutates into a form that makes it more transmissible to humans and, more importantly, between humans.

Here's some suggestions based on what we know about the spread of the disease.

1. Limit poultry/wild bird contact

In Iraq and around the world, those most at risk for human disease are owners of poultry flocks that can interact with wild birds. In the case of ducks and geese, it is common for wild ducks to visit outdoor flocks. Other birds like crows and sparrows frequently enter poultry enclosures to eat the domestic bird's food. Several European countries have recognised this particular risk and ordered flocks moved indoors. In England the Ravens at the Tower of London have been moved inside as a protective measure. Even though there have been a number of outbreaks in large intensive poultry farms, the workers at these farms don't seem to be at high risk for infection.

For the average urban Iraqi in Mosul, Baghdad or Basra the risk of bird flu in its current form is negligible and should not be high on their priority list of risks. The same is true for most foreign military and civilian personnel who generally are not exposed to or eat local poultry. Should bird flu mutate into a highly transmissible disease among people (like the standard Influenza A) all bets are off as a pandemic develops worldwide.

For those most at risk, recognizing that a dead bird could be a risk to their health will go a long way. Quick treatment for H5N1 infection is also important. It is generally true that the quicker the patient is treated the better the outcome. Getting appropriate antivirals like Tamiflu within 48 hours of symptoms is very important. In human disease if left too long the damage cannot be undone with drugs.

If I had a flock outside the outbreak area, I would keep a close eye out for symptoms in the birds like plumetting egg production or edema in the face and comb. If something happened like in other outbreaks such as dozens or hundreds of my birds are dead one morning, I would be very concerned and would not go poking around the remaining birds. I would report the incident as soon as I could. If I started feeling ill with respiratory or flu like illness I would go to the nearest significant size hospital and let them know my recent history.

I know in each step there are many barriers, however this is an idealized case.

Recognize sick birds/don't handle sick or dead birds.
Educating people about watching out for sick birds and properly disposing of them is an important step. Most cases of bird flu in humans came in contact with a sick bird either in a bird market or at home. A more insidious problem is when sick birds are slaughtered and sold in the market. These carcasses could be sources of infection. A good step, which could involve coalition military resources, would to be to produce a simple 1 page factsheet that describes what to look for and what to do if a person suspects their birds are dying of bird flu. Put it on the internet, print it in the papers, put it on TV, send people around to the villages. Stress that people will be compensated and that they have an important role to play in fighting the disease. Also stress that by employing culls, nearby Turkey has controlled the disease for now.
Reports of people hiding birds or slaughtering and eating them before the cull need to be addressed with proper education and appropriate compensation.

3. If possible - leave the culling of flocks to appropriately equipped workers.
There is some evidence that improper culling of infected flocks has led to human cases. The messy physical nature of the cull, coupled with close contact is a recipe for disaster. Workers need protective gear, at a minimum respiratory protection, gloves and impermeable coveralls. Here again, perhaps coalition military personnel could assist in transportation of teams to remote areas or provide some other logistic help like the aquisition of protective gear.

A useful document is available on the OIE website
Guidelines for the Killing of Animals for Disease Control Purposes - Appendix 3.7.6. of the OIE Terrestrial Animal Health Code 2005

The WHO has suggested a few other things for people involved in the cull of infected birds. They recommend that they be vaccinated with the current influenza vaccine. The purpose of this is to minimize the risk that they be infected with a human Influenza A virus and bird flu at the same time. This might allow the reassortment of genes creating a more dangerous bird flu. The current vaccine does not protect against H5N1. These workers should also be screened and monitored for flu-like illness or conjunctivitis and blood tests should be taken to test for exposure to H5N1 virus.

4. Limit close contact with wild birds
I have read reports that the Iraqi government has banned bird hunting throughout the country. This is easier said than done. Bird hunting is sometimes a subsistence level activity and waterfowl as well as shorebirds and gamebirds such as quail and francolin are hunted throughout the country. I have no data on this but I would rank migratory waterbirds higher on the risk scale than resident landbirds such as francolins. There are no clearcut human cases associated with wild birds, but it remains a possibility.

5. Ban movement of poultry over international borders and within the country
The movement of poultry, especially Chickens has played a major part in the global spread of H5N1. It is interesting that both Japan and South Korea have not experienced additional H5N1 outbreaks since instituting strict bans on the import of poultry. Someone recently said that globalization had made the chicken the world's #1 migratory bird. This is not an understatement. China alone has over 9 billion chickens. Chickens move in huge numbers all around the world through trade. We don't know but this may have played a role in both the Turkish and Nigerian outbreaks. Chickens bred in China were sold in Turkey and apparently Nigeria gets many of its commercial chickens from Turkey. It is possible that bird flu has spread more by chickens and that wild birds were infected by domestic poultry.

6. Begin active surveillance for H5N1 in poultry, wild birds and people.
Active surveillance means trying to find the disease by looking for and testing sick birds, more testing of people with respiratory symptoms, random testing of waterfowl, etc. It serves two purposes. First you get a better handle on the extent of the outbreak and can make more informed statements about risk. The second is that it makes the public more confident that the people in charge are actively doing something instead of just reacting to uncontrollable events. A specific application might be intensive testing of commercial egg laying flocks. An active surveillance program might preserve the viability of parts of the poultry industry by ensuring the flocks are safe and the products they produce won't harm the public.

7. Consider vaccination for village and backyard flocks
This option was previously discounted because in some cases a bird can still shed virus, even though they might not show symptoms. The thinking is evolving and some have advocated vaccination because culling is sometimes impractical because chickens are the main source of protein in some areas. The Dutch are now requesting to vaccinate their flocks because of their experience in 2003 with a gigantic cull of 30 million birds and the attending economic fallout. Application of such a plan would be in the realm of the poultry experts.

Here's some online resources on Avian Influenza
Centers for Disease Control
World Health Organization
OIE (World Animal Health Organization)

Ok, that's all I'm going to write for now. I'll update this post as warranted and cross-post on the bird flu site. My next post on Birding Babylon will be on a cheerier note.