Prepared by:
Prof. Dr. Mohammed bin Saleh Al-Hajjaj
Professor of Chest Diseases, and Chairman of the Saudi Thoracic Society
Index:
Introduction
Current Situation in the Kingdom of Saudi Arabia
Global Current Situation
Avian Influenza Virus (H5N1)
Infection Transmission among Birds
Infection Transmission to Humans
General World Influenza Pandemic
Means of Prevention
Ways of Diagnosing & Treating Diseased Cases
Recommended Material
Coordination with the Relevant Authorities
Introduction:
The highly pathogenic influenza A virus subtype H5N1 is an emerging avian influenza virus that has been causing global concern as a potential pandemic threat. It is often referred to simply as "bird flu" or "avian influenza", even though it is only one subtype of avian influenza-causing virus.
H5N1 has killed millions of poultry in a growing number of countries throughout Asia, Europe and Africa. Health experts are concerned that the coexistence of human flu viruses and avian flu viruses (especially H5N1) will provide an opportunity for genetic material to be exchanged between species-specific viruses, possibly creating a new virulent influenza strain that is easily transmissible and lethal to humans. The mortality rate for humans with H5N1 is 60%.
Since the first H5N1 outbreak occurred in 1987, there has been an increasing number of HPAI H5N1 bird-to-human transmissions, leading to clinically severe and fatal human infections. Because a significant species barrier exists between birds and humans, though, the virus does not easily cross over to humans, though some cases of infection are being researched to discern whether human-to-human transmission is occurring. More research is necessary to understand the pathogenesis and epidemiology of the H5N1 virus in humans. Exposure routes and other disease transmission characteristics, such as genetic and immunological factors that may increase the likelihood of infection, are not clearly understood.
Epidemiologists are afraid the next time such a virus mutates, it could pass from human to human; however, the current A/H5N1 virus does not transmit easily from human to human. If this form of transmission occurs, another pandemic could result. Thus, disease-control centers around the world are making avian flu a top priority. These organizations encourage poultry-related operations to develop a preemptive plan to prevent the spread of H5N1 and its potentially pandemic strains. The recommended plans center on providing protective clothing for workers and isolating flocks to prevent the spread of the virus.
Hunting hobby could be a source of infection.
Current Situation in the Kingdom of Saudi Arabia:
So far, the not a single avian influenza case has been recorded the Kingdom, among poultry or humans. However, it is quite known that the Kingdom receives more than 270 types of migratory birds from Asia and Europe, and it is highly probable that such birds get in touch with domestic birds, and carry infection into the country.
Some experts hold the viewpoint that the Kingdom, owing to its wideness and mild weather in winter, if compared with the countries of the northern hemisphere, it receives about 10 per cent of the total bird migrations around the world, comprised of hundreds of thousands of bird flocks of different types. Besides, the Kingdom receives thousands of ornamental birds and hunting birds, directly or through the other Gulf States. Given such birds may be coming from stricken countries, the avian influenza virus could be possibly transmitted into the Kingdom.
Imported ornamental birds may transmit the infection
Although the large poultry farms around the Kingdom are well closed, and are unlikely to be infected, most small poultry projects, though producing 70 per cent of chicken meat, are open, and prone to infection by getting in contact with migratory birds or other infected poultry. The main danger, however, lies in the infection transmission from human to human. This may lead up to a devastating pandemic sweeping the whole country, Allah forbid!
Global Current Situation:
The highly pathogenic avian influenza A (H5N1) epizootic (animal outbreak) in Asia, Europe, the Near East, and Africa is not expected to diminish significantly in the short term. It is likely that H5N1 virus infections among domestic poultry have become endemic in certain areas and that sporadic human infections resulting from direct contact with infected poultry and/or wild birds will continue to occur. So far, the spread of H5N1 virus from person-to-person has been very rare, limited and unsustained. However, this epizootic continues to pose an important public health threat.
There is little pre-existing natural immunity to H5N1 virus infection in the human population. If H5N1 viruses gain the ability for efficient and sustained transmission among humans, an influenza pandemic could result, with potentially high rates of illness and death worldwide. No evidence for genetic reassortment between human and avian influenza A virus genes has been found to date, and there is no evidence of any significant changes to circulating H5N1 virus strains to suggest greater transmissibility to or among humans. Genetic sequencing of avian influenza A (H5N1) viruses from human cases in Vietnam, Thailand, and Indonesia shows resistance to the antiviral medications amantadine and rimantadine, two of the medications commonly used for treatment of influenza. This leaves two remaining antiviral medications (oseltamivir and zanamivir) that should still be effective against currently circulating strains of H5N1 viruses. A small number of oseltamivir resistant H5N1 virus infections of humans have been reported. Efforts to produce pre-pandemic vaccine candidates for humans that would be effective against avian influenza A (H5N1) viruses are ongoing. However, no H5N1 vaccines are currently available for human use.
Research suggests that currently circulating strains of H5N1 viruses are becoming more capable of causing disease (pathogenic) in animals than were earlier H5N1 viruses. One study found that ducks infected with H5N1 virus are now shedding more virus for longer periods without showing symptoms of illness. This finding has implications for the role of ducks in transmitting disease to other birds and possibly to humans as well. Additionally, other findings have documented H5N1 virus infection among pigs in China and Vietnam; H5N1 virus infection of cats (experimental infection of housecats in the Netherlands, isolation of H5N1 virus from domestic cats in Germany and Thailand, and detection of H5N1 viral RNA in domestic cats in Iraq and Austria); H5N1 virus infection of dogs (isolation of H5N1 virus from a domestic dog in Thailand); and isolation of H5N1 viruses from tigers and leopards at zoos in Thailand). In addition, H5N1 virus infection in a wild stone marten (a weasel-like mammal) was reported in Germany and in a wild civet cat in Vietnam. Avian influenza A (H5N1) virus strains that emerged in Asia in 2003 continue to evolve and may adapt so that other mammals may be susceptible to infection as well.
Avian Influenza Virus (H5N1):
H5N1 is an Influenza A virus subtype. Experts believe it might mutate into a form that transmits easily from person to person. If such a mutation occurs, it might remain an H5N1 subtype or could shift subtypes as did H2N2 when it evolved into the Hong Kong Flu strain of H3N2.
H5N1 has mutated through antigenic drift into dozens of highly pathogenic varieties, but all currently belonging to genotype Z of avian influenza virus H5N1. Genotype Z emerged through reassortment in 2002 from earlier highly pathogenic genotypes of H5N1 that first appeared in China in 1996 in birds and in Hong Kong in 1997 in humans. The "H5N1 viruses from human infections and the closely related avian viruses isolated in 2004 and 2005 belong to a single genotype, often referred to as genotype Z."
This infection of humans coincided with an epizootic (an epidemic in nonhumans) of H5N1 influenza in Hong Kong’s poultry population. This panzootic (a disease affecting animals of many species especially over a wide area) outbreak was stopped by the killing of the entire domestic poultry population within the territory. The name H5N1 refers to the subtypes of surface antigens present on the virus: hemagglutinin type 5 and neuraminidase type 1.
Model of avian influenza virus
Historical Background:
It is believed that outbreaks of highly pathogenic avian influenza (HPAI) occurred in Italy and other European countries prior to the first description by Perroncito and the differentiation from fowl cholera by Rivolta and Delprato in 1878 as reported by Stubs. There are reports of subsequent outbreaks of HPAI in 1894 and 1901 in Italy, which spread with the stock of an itinerary poultry merchant to eastern Austria and Germany and later to Belgium and France. The spread of HPAI through Germany was aided by the 1901 Brunswick poultry show, where after the detection of sick birds, the authorities panicked, closed the show and send the affected flock to their places of origin, spreading the outbreak even further. HPAI became endemic throughout Italy and Central Europe until it disappeared around the mid 1930. However, it is important to note that the lack of appropriate diagnostic tests and the concurrent circulation of Newcastle disease virus among poultry during the early 1900s, makes it impossible to determine which of the two viruses were responsible for the reported outbreaks. By the mid 1900s, HPAI had been reported in most of Europe, Russia, North America, South America, Middle East, Africa and Asia
Types, Subtypes and Strains of Influenza Virus:
There are three major types of influenza viruses: A, B, and C. Only influenza A viruses are further classified into subtypes on the basis of the two main surface glycoproteins hemagglutinin (HA) and neuraminidase (NA). Influenza A subtypes and B viruses are further classified by strains. Avian influenza virus can be distinguished as Low Pathogenic Avian Influenza (LPAI) and Highly Pathogenic Avian Influenza (HPAI) forms based on genetic features of the virus and the severity of the illness they cause in poultry.
Influenza virus A is usually responsible for bird flu (Avian influenza) but same time also responsible for pandemics of influenza in humans. Out of hundreds of strains of avian influenza A viruses, only four are capable to produce infection in humans: H5N1, H7N3, H7N7 and H9N2. Out of these, highly pathogenic avian influenza, H5N1strain is of greatest concern for human infection. This virus has affected poultry flocks and other birds in more than 50 countries. Total 309 laboratory-confirmed cases of avian influenza infection in humans have been reported to the World Health Organization between end of December 2003 to end of May 2007; out of which 187 deaths were confirmed.
While human cases remain relatively rare and are largely the result of direct virus transmission from infected birds, a few cases of human-to-human transmission have been reported. But still there is a matter of great assurance that, H5N1strain does not easily cross from birds to infect humans. Oseltamivir is the first orally active antiviral drug used in the treatment and prophylaxis of influenza A and B viruses provided that the treatment is started within 48 hours of onset of symptoms.
Of the 15 avian influenza virus subtypes, H5N1 is of particular concern for several reasons. 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.
If more humans become infected over time, the likelihood also increases that humans, if concurrently infected with human and avian influenza strains, could serve as the “mixing vessel” for the emergence of a novel sub-type with sufficient human genes to be easily transmitted from person to person. Such an event would mark the start of an influenza pandemic.
Low Pathogenic (LPAI) vs. Highly Pathogenic Avian Influenza (HPAI):
H5 and H7 subtypes of avian influenza A viruses can be further classified as either highly pathogenic avian influenza (HPAI) or low pathogenic avian influenza (LPAI). This distinction is made on the basis of genetic features of the virus. HPAI is usually associated with high mortality in poultry. It is not certain how the distinction between “low pathogenic” and “highly pathogenic” is related to the risk of disease in people. HPAI viruses can kill 90 to 100% of infected chickens, whereas LPAI viruses cause less severe or no illness if they infect chickens. Because LPAI viruses can evolve into HPAI viruses, outbreaks of H5 and H7 LPAI are closely monitored by animal health officials.
"Path" refers to pathogenic and reflects the fact that it is not a killer. H5 is an intestinal virus in birds. In North America many birds have tested LP H5N1 positive. As long as it does not mutate to High Path (HPAI) we need not fear it. High Path H5N1 (a merciless killer) originated in Southeastern China where peasants live in close proximity to ducks and chickens and pigs and are exposed to fecal contamination of their living and sleeping spaces and even their food. An intestinal (epithalial tissue) virus in birds can become a nose and throat and lungs (all epithalial tissue) virus in pigs and humans and other animals like cats and dogs. High Path kills all of its human hosts with about 60 percent or greater efficiency. You want to avoid it as much as possible.
Low Path Bird Flu strains can mutate into High Path strains at any time. Just like Low Path H5N1 mutated into High Path H5N1 in China and then spread to the rest Asia, Europe and Africa, we have seen H7N2 mutate from low path into a high path virus in the Eastern United States. In 2002, in Virginia there was an H7N2 Outbreak among poultry in the Shenandoah Valley, with 1 person found to have seriologic evidence of infection. Again in New York State in 2003 there was one person hospitalized.
Again in 2003 in the Netherlands there were H7N7 Outbreaks in poultry on several farms, followed by infections among pigs and humans. A total of 89 people were confirmed to have infection; most were poultry workers. One death occurred, a veterinarian who visited one of the affected farms. Most cases resulted from direct contact with infected poultry; 3 cases possibly were person-to-person transmission.
Influenza virus and its components under the microscope
How Influenza Viruses Change: Drift and Shift
Influenza viruses can change in two different ways.
A) Antigenic Drift: which occurs through small changes in the virus that happen continually over time. Antigenic drift produces new virus strains that may not be recognized by antibodies to earlier influenza strains. This process works as follows: a person infected with a particular flu virus strain develops antibody against that virus. As newer virus strains appear, the antibodies against the older strains no longer recognize the "newer" virus, and infection with a new strain can occur. This is one of the main reasons why people can get the flu more than one time. In most years, one or two of the three virus strains in the influenza vaccine are updated to keep up with the changes in the circulating flu viruses. For this reason, people who want to be immunized against influenza need to receive a flu vaccination every year.
B) Antigenic Shift: antigenic shift is an abrupt, major change in the influenza A viruses, resulting in a new influenza virus that can infect humans and has a hemagglutinin protein or hemagglutinin and neuraminidase protein combination that has not been seen in humans for many years. Antigenic shift results in a new influenza A subtype. If a new subtype of influenza A virus is introduced into the human population, if most people have little or no protection against the new virus, and if the virus can spread easily from person to person, a pandemic (worldwide spread) may occur.
H5N1 Virus Strain:
H5N1 avian influenza is a subtype of influenza A virus that was first isolated from birds in South Africa in 1961. In 1997 a unique, highly pathogenic strain of H5N1 appeared in poultry in Hong Kong and has subsequently spread throughout Asia. This unique strain of H5N1 avian influenza is deadly to domestic poultry. Some species of birds infected with this virus remain asymptomatic after infection and are therefore considered to be silent vectors.
In addition to infecting birds, the H5N1 influenza virus can also infect some mammals, including humans; however, transmission to humans does not easily occur. Since 1997, there have been 117 cases of H5N1 influenza in humans, of which, 60 (51%) were fatal. Most of these case-patients were infected from direct and close contact with infected poultry or surfaces contaminated with their feces; however, some appear to have contracted the virus from close contact (e.g., household) with an infected person. There have been no documented reports of human-to-human H5N1 transmission to casual contacts. To date, H5N1 influenza virus has not been identified among humans or birds in North America. The U.S. Centers for Disease Control and Prevention (CDC) recommends enhanced surveillance efforts to identify possible cases of H5N1 influenza.
Studies done in laboratories suggest that the prescription medicines approved for human flu viruses should work in preventing bird flu infection in humans. However, flu viruses can become resistant to these drugs, so these medications may not always work. Additional studies are needed to prove the effectiveness of these medicines.
Why is H5N1 type (influenza A virus)is of greatest concern for human infection?
For several reasons, including:
- It can cause severe diseases in human.
- The birds that survive infection excrete virus for at least 10 days, orally and through faces, helping spread of the virus at poultry markets and also by migratory birds.
- It mutates rapidly and seems to acquire genes from virus infecting other animal species.
- The more humans get infection, the people can become infected both human and bird flu strainsز
- The virus may cause severe diseases, and may lead up to death.
- Poultry, when infected, cannot eliminate the virus. Even after recovery, they continue to excrete the virus for at least 10 days.
- Migratory birds can carry the virus without suffering from any symptoms; what makes it even harder to detect.
Human-to-human infection is still probable.
Migratory birds get in contact with domestic birds, and transmit infection to them.
H5N1 Transmission among Birds:
Infected birds shed avian influenza virus in their saliva, nasal secretions, and feces. Domestic poultry become infected with the virus through direct contact with infected waterfowl or other infected poultry, or through contact with contaminated surfaces and material.
According to the United Nations FAO, wild water fowl likely plays a role in the avian influenza cycle and could be the initial source for AI viruses, which may be passed on through contact with resident water fowl or domestic poultry, particularly domestic ducks. A newly mutated virus could circulate within the domestic and possibly resident bird populations until highly pathogenic avian influenza (HPAI) arises. This new virus is pathogenic to poultry and possibly to the wild birds that it arose from.
Wild birds found to have been infected with HPAI were either sick or dead. This could possibly affect the ability of these birds to carry HPAI for long distances. However, the findings in Qinghai Lake-China, suggest that H5N1 viruses could possibly be transmitted between migratory birds. Additionally, the new outbreaks of HPAI in poultry and wild birds in Russia, Kazakhstan, Western China and Mongolia may indicate that migratory birds probably act as carriers for the transport of HPAI over longer distances. Short distance transmission between farms, villages or contaminated local water bodies is likewise a distinct possibility.
As the virus circulates within the domestic and possibly resident wild bird populations, it can mutate in new forms of the virus. Low pathogenic forms of the virus, particularly H5 and H7 subtypes, can mutate into highly pathogenic avian influenza (HPAI). The newly formed virus is pathogenic to poultry and possibly to the wild birds from which it arose.
How highly pathogenic avian influenza (HPAI) is initially introduced into poultry flocks remains unclear. However, the spread of avian influenza between poultry facilities almost always results from the movement of infected birds or contaminated people and equipment (including clothing, boots, and vehicles). Avian influenza virus can also be found on the outer surfaces of egg shells (but rarely inside); therefore, egg transfer is a potential means of avian influenza transmission. Airborne transmission of avian influenza virus from farm to farm is not likely.
The AI virus has adapted to the environment in ways such as using water for survival and to spread, and creating a reservoir (ducks) strictly tied to water. The water in turn influences movement, social behavior and migration patterns of water bird species. It is therefore of great importance to know the ecological strategy of influenza virus as well, in order to fully understand this disease and to control outbreaks when they occur. Most research is needed concerning HPAI viruses in wild birds. For example, small birds like sparrows, starlings and pigeons can be infected with deadly H5N1 strains and they can carry the virus from chicken house to chicken house causing massive epidemics among the chickens.
Infection Transmission to Humans:
Infection is mainly transmitted through direct contact with the live infected birds, either direct or indirect. So it is considered the main cause of infection. The virus could be transmitted also through the birds' mouth secretions and excretion. Therefore most bird flu cases have been detected in rural areas. The possibility of infection transmission becomes even higher in during slaughtering and cleansing the infected birds. The virus cannot be transmitted to humans when eating infected birds, or their eggs, in case they are well cooked at a temperature of at least 70° C.
Human infection could also caused by the contamination of the tools or clothes of the workers at poultry farms with the virus included in the birds' secretions and wastes. The virus can live for relatively long time in low-temperature environments.
It should be noted that the possibility of infection transmission to humans is still very low, considering the hundreds of millions of culled birds, if compared to only 70 deaths among humans so far.
So far, H5N1 infections in humans are attributed to bird-to-human transmission of the virus in most cases, and no human-to-human transmission has been recorded. Nevertheless, this does not relinquish the possibility that a genetic mutation may take place, causing the virus to be transmitted among humans, in a pandemic manner.
Poultry are the main source of direct transmission to humans
Vulnerable Persons:
- Poultry workers.
- Persons working in transporting, slaughtering and preparing poultry.
- Vets and technicians.
- Laboratory workers dealing with avian influenza specimens.
- Fans of wild hunting.
Poultry workers might be infected through direct contact with infected birds.
Infection could be transmitted to butchers during slaughtering and preparing infected birds.
Global Pandemic:
A pandemic is an epidemic of infectious disease that is spreading through human populations across a large region; for instance a continent, or even worldwide. A widespread endemic disease that is stable in terms of how many people are getting sick from it is not a pandemic. Further, flu pandemics exclude seasonal flu, unless the flu of the season is a pandemic. Throughout history there have been a number of pandemics, such as smallpox and tuberculosis. More recent pandemics include the HIV pandemic and the 2009 flu pandemic.
The World Health Organization (WHO) has produced a six-stage classification that describes the process by which a novel influenza virus moves from the first few infections in humans through to a pandemic. This starts with the virus mostly infecting animals, with a few cases where animals infect people, then moves through the stage where the virus begins to spread directly between people, and ends with a pandemic when infections from the new virus have spread worldwide.
Three global pandemics took place in the course of the 20th century, the first of which was the pandemic called "Spanish Pandemic" (H1N1), in 1918-1919, resulting in the death of 500.000 persons in the US, and nearly 50.000.000 persons throughout the world. In 1957-1958, the Asian influenza made its appearance and resulted in the death of 70.000 persons in the US alone. The following global pandemic was the Hong Kong influenza (H3N2), in 1968-1969, killing 34.000 in the US.
Global Pandemic Phases:
The World Health Organization (WHO) has set a plan for pandemic influenza, divided into three periods and six phases.
Interpandemic Period:
Phase 1. No new1 influenza virus subtypes have been detected in humans. An influenza virus subtype that has caused human infection or disease may or may not be present in animals. If present in animals, the risk of human infection or disease is considered to be low.
Phase 2. No new1 influenza virus subtypes have been detected in humans. However, a circulating animal influenza virus subtype poses a substantial risk of human disease.
Pandemic Alert Period:
Phase 3. Human infection(s) with a new subtype, but no human-to-human spread, or at most rare instances of spread to a close contact.
Phase 4. Small cluster(s) with limited human-to-human transmission but spread is highly localized, suggesting that the virus is not well adapted to humans.
Phase 5. Larger cluster(s) but human-to-human spread still localized, suggesting that the virus is becoming increasingly better adapted to humans, but may not yet be fully transmissible (substantial pandemic risk).
Pandemic period:
Phase 6. is characterized by community level outbreaks in at least one other country in a different WHO region in addition to the criteria defined in Phase 5. Designation of this phase will indicate that a global pandemic is under way.
During the post-peak period, pandemic disease levels in most countries with adequate surveillance will have dropped below peak observed levels. The post-peak period signifies that pandemic activity appears to be decreasing; however, it is uncertain if additional waves will occur and countries will need to be prepared for a second wave.
Means of Prevention:
Fighting the Disease in Birds:
In case of the emergence of the signs and indications foreshadowing the occurrence of a pandemic, there will be three targets to be fulfilled in order to fight the disease in birds:
Infection Control in Poultry:
The application of health quarantine to poultry farms and markets, and elimination of all the infected or suspected to be infected birds could be seen as the optimal factor of preventing viral transmission to other farms, given H5N1 is a highly contagious virus, and could be transmitted from a farm to another through the contaminated instruments, vehicles, or even the workers' clothes.
The highly pathogenic avian influenza (HPAI) can live for a quite long period, especially in low-temperature environments. Taking this into consideration, taking strict precautions (as regards the purgation and sterilization of poultry farms) would be peculiarly important.
In case of the absence of effective means of infection control, the infection may persist for a long time, as happened in Mexico, when the pandemic began in 1992 with a low pathogenic virus, and then developed into a high pathogenic virus, and was not controlled until 1995.
The H5N1 virus, as already shown, is continuously evolving during the viral replication inside the infected body in a gradual manner; such that makes the body unable to identify the virus, and the antibodies non-effective, to the effect that one person might be infected more than once. Nevertheless, abrupt viral mutations still pose the most catastrophic risks. Such mutations take place by means of mixture between the genes of an avian influenza virus (for instance, H5N1) and the human influenza virus, leading up to the emergence of a completely new virus, combining the hazard of avian influenza, and the prevalence of human influenza (from human to human). Thereupon the devastating global pandemic occurs, threatening the human community as a whole, given the non-effectiveness of the currently available medicines and antivirals.
Likewise, a pandemic is feared to take place through the infection of pigs with the two type of influenza, giving way to the emergence of a new virus. Still, some other scientists, proceeding from recent discoveries, opine that human beings themselves could be the arena of viral mixture. They could be infected with the two types of influenza (avian and human) synonymously, leading up to human-to-human transmission.
Formerly, it had been demonstrated that all the 15 avian influenza stains are not infectious beyond birds and pigs, till the H5N1 outbreak in Hong Kong in 1997 that infected 18 persons, out of which 6 patients died. The outbreak was cause by the existence of a highly pathogenic virus in poultry, and it was not controlled until all the country's poultry had been culled (1.5 million birds.)
The World Health Organization (WHO) has set a strategy to control H5N1 infection in birds, summed up as follows:
- Epidemiological surveillance: aiming at early detection of infection among migratory birds, and banning hunting.
- Reduction bird transport among farms: and preventing different bird species from existing in one place.
- Banning the import of live birds at all ages, as well as frozen meat and meat products from the pandemic-stricken countries.
- In case of the emergence of any infection among birds: All the birds existent in the infection place should be immediately culled and the birds in the surrounding places should be vaccinated. In addition, Tamiflu or Relenza should be given to all persons in contact with these birds.
- Monitoring poultry farms and markets, as well as the meat factories, so as to ensure they are free from infection.
Specialized Laboratories:
Proceeding from the fact that H5N1 is a highly pathogenic virus, all the precautions necessary for preventing the infection transmission to laboratory workers when examining infected specimens, should be taken. Also, there should be a central laboratory to receive all the specimens taken from patients or infected birds, paying thorough attention to the necessary precautions when transmitting the blood samples or body secretions.
In case of suspicion, a blood sample is taken from birds to be examined.
Precaution to be taken by the medical team when dealing with suspected H5N1 cases:
- Taking care when dealing with any of the suspected cases, and washing hands with a sterilizer before and after dealing with any case.
- Wearing personal protective equipment (PPE) when handling laboratory specimen, or other secretions; including gloves, high-quality facemask (N95), or a surgical facemask, in addition to an apron with long sleeves, a head cover and glasses.
- Being cautious when dealing with the patient's tools and belongings.
- Prevention against syringes and other surgical instruments.
- Cleanliness of the surrounding environment, and eliminations of wastes.
- Assigning an isolated room with negative pressure for the patient.
Taking prevention procedures when dealing with patients
Means of Personal Protection:
- Close contact with poultry or even wild ducks should be avoided.
- Poultry meat, eggs, duck products, pig meats should not be taken.
- As flesh and eggs of affected birds contains viruses, so these should not be exposed to persons without protective gloves, masks, goggles etc.
- Cooking methods of flesh and eggs should be such that the center of the product reaches a minimum temperature of 70°C.
- All persons who have been in close contact with infected animals should wash their hands frequently with soap and water.
- All concerned should be vaccinated with the current WHO recommended influenza vaccine as soon as possible prior to anticipate risk exposure.
- Concern cullers and transporters should be provided with personal protective equipments e.g. impermeable apron, rubber boots, goggles etc.
- Serological surveillance of exposed animal workers easily and veterinarians is encouraged.
It should be noted, at length, that the health authorities should proceed on the implementation of a comprehen sive preventive program, with the aim to prevent infection transmission to the domestic environment. This can be attained by taking the necessary precautions (such as banning the import of all kinds of birds from pandemic-stricken countries, monitoring the disease in domestic birds, and eliminating any infected cases, in addition to applying health quarantine to all those in contact with them, providing the necessary health care to those infected, and providing adequate quantities of Tamiflu to be used when need be.)
Precautions to prevent human-to-human infection:
All those suffering from the symptoms of avian influenza should take the following precautions:
• Covering the mouth and nose during coughing and sneezing.
• Using handkerchiefs to prevent respiratory secretions from spreading out in the air, and throwing them away in coverable trash baskets, those opened by feet, so as to be eliminated thereafter.
• Frequently washing hands by using water and soap after touching respiratory secretions. Using a proper sterilizer is recommended.
• Patients are advised to put on medical facemasks, especially in crowded places. It is advisable to wear such facemasks as well, especially in crowded and unventilated places.
• The medical team dealing with avian influenza cases (either suspected or confirmed) have to take all the necessary precautions to evade infection, to themselves or to others, by using medical gloves and facemasks, as well as the proper elimination of medical instruments and materials (gauze, cotton, etc.)
How to diminish the possibility of infection transmission, in case of the emergence of a pandemic among poultry in the area where you live:
You have to avoid all forms of contact with live poultry (chicken, ducks, geese, pigeons, etc.) as well as all the wild birds. Also, you should keep away from all the persons and situations that could possibly cause infection transmission (poultry farms, bird markets, etc.), and avoid touching domestic birds, meat and meat products, in addition to the instruments and utensils used in preparing chicken meat, and even the vehicles used in transporting them.
Besides, you have to pay close attention to personal hygiene, by washing hands with water and soap or a disinfectant on touching anything that might be a source of infection.
When preparing meat (slaughtering, cutting, chopping, etc.) it has to be away from the other foods, fresh or processed, and no to use the same instruments (knife, pan, etc.), as well as putting on hand gloves, before cooking the meat very well. Also, you have to ascertain the cleanliness of the place, by sterilizing it with effective disinfectants.
As for eggs, they have to be well washed before cooking, and removing any dirt that may be stuck to them. Then hands have to be well washed. Do not eat the yolk if loose or liquid.
The same procedures (or even stricter procedures) have to be taken in poultry farms and butcheries.
Remember: the avian influenza virus (H5N1) dies at a temperature of 70° C or higher.
Ways of infection transmission:
- The contact with the live infected birds, either direct or indirect, is considered the main cause of infection.
- The virus could be transmitted through the birds' mouth secretions and excretion.
- The virus can live for relatively long time in low-temperature environments.
- Human infection could also caused by the contamination of the tools or clothes of the workers at poultry farms with the virus included in the birds' secretions and wastes.
- Migratory and ornamental birds, as well as workers, coming from pandemic-stricken countries.
- Direct contact with infected birds in poultry marks, which helped a lot to prevail the infection, in a way that obliged farm owners, in Asia, to cull tens of millions of birds, given the vicinity of people's residence to these farms.
- The H5N1 virus is intensely existent in bird excretion (in poultry farms, bird cages, etc.)
- Insects (like mosquitoes) that transmit contaminated blood from one person to another.
- Rats and farm dogs, as the can function as intermediate hosts of the virus.
Incubation Period:
The incubation period ranges from few hours to 3 days for the single bird, and 14 days for the whole flock. The incubation period depends on the quantity and severity of the virus, as well as the bird kind, infection method, and the bird's resistance to the virus.
Following are some of the important and effective steps towards reducing the disease prevalence:
- Elimination of infected birds, by culling them, and protecting persons in touch with them, in addition to putting on facemasks and gloves when approaching such birds (since humans can transmit infection from one place to another through clothes and shoes.
- Banning the import of poultry, birds, or eggs from the pandemic-stricken countries.
- Vaccinating birds with certain medicines with the aim to control the disease. Vaccines are of two types: the killed vaccine, killing the virus, but almost ineffective in infection prevention, and the live vaccine, with its limited effectiveness too. This is because the rapidity of the viral changes and mutations, in addition of the ability of this viral strain to form a completely new virus, with distinct features and characteristics.
- Reduction of the viral activity or severity in the affected bird and poultry farms by raising temperature or exposing them to the direct sunlight, as well as using some disinfectants, such as formalin, sodium hydrochloride and, iodine and ammonia compounds for cleansing these farms.
- In case of the prevalence of the virus in lakes and ponds, the infection could be diminished by saturating the lakes with air (as in fishbowls), with the aim to make the virus float on the water surface, thus helping kill the virus through direct sunlight.
- As for as poultry farm workers, it is highly recommended to wearing personal protective equipment (PPE) when handling laboratory specimen, or other secretions; including gloves, high-quality facemask (N95), or a surgical facemask, in addition to an apron with long sleeves, a head cover and glasses. It will always be better to single-use instruments.
- Elimination of infected and dead birds by burning them, and then burying them in shallow pits, lest they should contaminate groundwater.
- Elimination of wastes (poultry excretions) in a healthy way, and putting them in special thick bags, and then burning them.
- Using barriers and nets to prevent any migratory bird to get in contact with the farm birds, as it might transmit the H5N1 infection to domestic birds.
- Banning the import of ornamental birds.
- Putting on protective glasses.
- Adherence to using advanced and high-tech instruments in poultry farms, such as the cages including certain places for food, and a belt to collect wastes and directly move them to the trash. The farms have to be covered and unexposed to the open air, and the wastes have to be eliminated regularly.
- Banning hunting of migratory birds, as they are more exposed to infection, and, accordingly, transmitting it to humans when touching them.
What should a person do in case of infection?
You have to pay close attention to any symptoms that might emerge, even though mild, such as rheuma, cough and high temperature. In case such symptoms continue for 10 days, then you should immediately see a doctor, and put on a facemask, taking into account not to get into contact with others. You will be supposed to tell the doctor about all the recent circumstances, and whether you have recently travelled, and where you have been to; in addition to any other information they might be useful in diagnosis.
Avian influenza Vaccine:
At present, there are no specific human vaccines protecting from avian influenza (H5N1), either fob birds or humans. Nevertheless, underway are relentless efforts seeking to develop and try some of the recently produced vaccines, for the purpose of limiting infection transmission.
Developing an effective anti-avian influenza vaccine is the only way to diminish its risk.
Precautions recommended to travelers:
It is highly recommended to make blood testing to those coming from pandemic-stricken countries, so as to ensure whether or not they are infected with avian influenza (H5N1), in case they are suffering from any respiratory symptoms (e.g. pneumonia), especially those who have been in contact with poultry (in poultry farms, markets, etc.)
- Precautions recommended for travelers to stricken places:
- So far, the WHO has not issued any travel bans to any of the countries affected by (H5N1).
- The WHO has not recommended any measures to be applied on those coming from the countries affected by (H5N1).
- It is advisable for travelers to see their doctors prior to heading for any of the countries affected by (H5N1). And on arrival, it is advisable to be aware of any health information or instructions concerning the infection, as well as any developments taking place during his stay.
- When traveling to any of the countries affected by (H5N1), it is recommended to:
- Avoid touching any birds or poultry (either live birds or meat), and keep away from their places.
- Keep away from the places with high infection probability, like poultry farms and bird parks.
- Avoid touching any of tools of aviculture or poultry transportation or storing, such as bird cages and bird pans.
- Avoid eating white meat unless very well cooked (considering the virus does not survive 70° C).
- Wash your hands well, by using water and soap.
Precautions recommended for Hajj-Pilgrims:
As a matter of fact, the possibility of infection transmission of the viruses affecting the respiratory system, especially influenza, becomes very much higher in congested places, especially when the crowds are of various nationalities. They might carry diseases in their bodies, which could be transmitted to others, who, in turn, carry such diseases to their countries. Hajj and Umrah are exemplary occasions for infection transmission. Kissing the Black Stone, for example, could be a way of infection transmission if one of the pilgrims who have kissed it is infected with any of the influenza virus types, sub-types and strains, given the virus could be transmitted through breathing and touching. Although human-to-human transmission is not yet proven, the expected viral mutation could take place at any time, and the virus could be transmitted from one person to another. Taking into consideration that massive numbers of people come from South East Asia (e.g. Indonesia and Malaysia), where the pandemic among birds emerged, and then was transmitted to people, it requires even more caution and preparedness for any emergency.
Following are a number of necessary tips recommended for pilgrims, when performing Hajj or Umrah:
- Taking this year's anti-influenza vaccine at least 10 days prior to setting out for Hajj, as well as other vaccines, for the purpose of prevention of human influenza, lest it should weaken you immunity, and to avoid the mixture of the two viruses, leading up to a global pandemic.
- Putting on protective facemasks in human agglomerations and congested places.
- Keeping to hygiene tips, most importantly washing hands frequently, and abstention form kissing or using others tools.
- In case of infection, you can take "Tamiflu" or "Relenza", which are effective against all strains of influenza, including H5N1. These medications prevent infection transmission.
Medical Cases:
Diagnosis & Treatment:
What is known about avian influenza, so far, is very little. However, it could be inferred from the confirmed H5N1 cases that the symptoms include: fever, throat pain and coughing. In the severe cases, that ended up dead, there was also viral pneumonia, causing respiratory failure, leading up to death. The diagnosis examinations are considerably fast, reliable, and available at ordinary laboratories. The specimen could be taken from the patient's blood or secretions. Nonetheless, virus transplantation and classification processes are available only in specialized laboratories.
Avian influenza (H5N1) is diagnosed and detected by knowing the familial history of avian influenza for those suspected to be infected by H5N1, or those who have been in contact (either direct or indirect) with infected birds (touching bird secretions, transport tools, etc.), or being in contact with an avian influenza patient, in addition to the symptoms of the disease, and finally the blood tests confirming the result of the diagnosis.
Symptoms of Avian Influenza (H5N1) in Humans:
The symptoms of H5N1 include:
- Seasonal flu symptoms: (chills, fever, sore throat, muscle pains, severe headache, coughing, weakness/fatigue and general discomfort).
- Eye infections
- Severe respiratory illness:
- Shortness of breath/difficulty breathing
- Pneumonia
- Acute respiratory distress
- Viral pneumonia
- Nausea and vomiting
- Abdominal pain
- Diarrhea
- Neurological changes:
- Seizures
Avian influenza, in its onset, is similar to human influenza.
Treatment:
At present, there are no specific human vaccines protecting from avian influenza. And underway are relentless efforts seeking to develop and try some of the recently produced vaccines. It is true that vaccination against human influenza may not protect those vaccinated from Bird Flu infection, yet, it is recommended for the most prone persons to be given this vaccine, to prevent the infection of human influenza simultaneously. This may cause the two viruses to exchange their genetic materials, giving way to the appearance of a new human virus, easy to be transmitted among humans.
Pneumonia is one of most hazardous complications of avian influenza.
There is no highly effective treatment for H5N1 flu, but oseltamivir (commercially marketed by Roche as Tamiflu), can sometimes inhibit the influenza virus from spreading inside the user's body. This drug has become a focus for some governments and organizations trying to prepare for a possible H5N1 pandemic. On April 20, 2006, Roche AG announced that a stockpile of three million treatment courses of Tamiflu are waiting at the disposal of the World Health Organization to be used in case of a flu pandemic; separately Roche donated two million courses to the WHO for use in developing nations that may be affected by such a pandemic but lack the ability to purchase large quantities of the drug.
Animal and lab studies suggest that Relenza (zanamivir), which is in the same class of drugs as Tamiflu, may also be effective against H5N1. In a study performed on mice in 2000, "zanamivir was shown to be efficacious in treating avian influenza viruses H9N2, H6N1, and H5N1 transmissible to mammals". In addition, mice studies suggest the combination of zanamivir, celecoxib and mesalazine looks promising producing a 50% survival rate compared to no survival in the placebo arm. While no one knows if zanamivir will be useful or not on a yet to exist pandemic strain of H5N1, it might be useful to stockpile zanamivir as well as oseltamivir in the event of an H5N1 influenza pandemic. Neither oseltamivir nor zanamivir can currently be manufactured in quantities that would be meaningful once efficient human transmission starts. In September, 2006, a WHO scientist announced that studies had confirmed cases of H5N1 strains resistant to Tamiflu and Amantadine. Tamiflu-resistant strains have also appeared in the EU, which remain sensitive to Relenza.
Avian influenza medications:
Anti-viral drugs are given to humans who may be infected with Avian Flu. These drugs are also used to combat human influenza.
In the United States, four antiviral medications are approved for treatment of influenza. These are:
- Amantadine
- Rimantadine
- Oseltamivir
- Zanamivir (limited supply)
When used for treatment within the first two days of illness, all four antiviral medications are similarly effective in reducing the duration of illness by one or two days. People who are at high risk of serious complications from avian flu are given top priority to these medications. Three of these antiviral medications (amantadine, rimantadine, and oseltamivir) are also approved for prophylaxis (prevention) of influenza.
It is recommended that any person experiencing a potentially life-threatening influenza-related illness should be treated with antiviral medications. Also, any person at high risk for serious complications of influenza and who is within the first 2 days of illness onset should be treated with antiviral medications. In children, rimantadine is approved for prophylaxis among children aged >1 year and for treatment and prophylaxis of influenza among adults. Although rimantadine is approved only for prophylaxis of influenza among children, certain specialists in the management of influenza consider it appropriate for treatment of influenza among children. Also available for treatment of children (>1 year) are amantadine and oseltamivir, or zanamivir for children aged over 7 years.
Tamiflu may be effective in the prevention of avian influenza (H5N1).
Effectiveness of these medicines:
All these drugs could be used for the prevention and treatment of avian influenza, as follows:
- Oseltamivir (Tamiflu): vomiting and nausea.
- Zanamivir (Relenza): cough, headache, diarrhea, and dizziness. It is not recommended for people with chest diseases, as it may cause contraction of the airways.
It is not yet ascertained whether these drugs could be used with pregnancy. Besides, according to one of the studies conducted in this respect, that the virus's resistance to the drug is estimated as 5.5%.
Although oseltamivir (Tamiflu) is recommended for prevention, both Tamiflu and Relenza have proven substantial effectiveness in prevention of avian influenza by over 82-84%. There is no discrepancy between using such drugs and the ongoing unstintling efforts to find an avian-specific vaccine.
Educational Material:
FAQ
are a number of the most frequently asked questions, concerning the diseases and its risk, along with their apt answers:
Q: How could the avian influenza virus (H5N1) be transmitted to humans?
A: It had been believed that H5N1 can affect birds only, before the first human case emerged in Hong Kong in 1997. Infection is mainly transmitted through direct contact with the live infected birds, either direct or indirect. So it is considered the main cause of infection. The virus could be transmitted also through the birds' mouth secretions and excretion. Therefore most bird flu cases have been detected in rural areas. The possibility of infection transmission becomes even higher in during slaughtering and cleansing the infected birds. The virus cannot be transmitted to humans when eating infected birds, or their eggs, in case they are well cooked at a temperature of at least 70° C.
Human infection could also caused by the contamination of the tools or clothes of the workers at poultry farms with the virus included in the birds' secretions and wastes. The virus can live for relatively long time in low-temperature environments.
It should be noted that the possibility of infection transmission to humans is still very low, considering the hundreds of millions of culled birds, if compared to only 70 deaths among humans so far.
Q:Is avian influenza a curable disease?
A: Avian influenza patients could recover from the disease by taking effective antibiotics. Scientists are now endeavoring to develop a specialized vaccine against the disease.
Q: To what extent is avian influenza dangerous?
A: The risk of death is high amongst avian influenza patients. It is estimated that 6 out of 18 patients died of the disease in 1997. Over the past few weeks, it resulted in the death of 10 patients. It should be clear, however, that avian influenza, so far, is nothing compared to the Severe Acute Respiratory Syndrome (SARS), which affected 8400 persons (out of which 800 persons died) around the world since its first outbreak in November 2002.
Q:Could the virus (H5N1) be possibly transmitted from one human to another?
A: Up till now, it has not been ascertained whether human-to-human infection could occur. However, for the sake of avoiding infection, it is advisable to keep away from poultry farms, which could be a source of infection.
Q: Why are experts worried with regard to avian influenza?
A: Experts are quit uneasy with the evolution of H5N1 lest it should merge with human influenza, making up a new virus, able to be transmitted among humans. This fusion could occur inside an avian-influenza patient.
Q: Should I refrain from eating chicken?
A: Well, you can continue to eat chicken, as experts affirm that H5N1 cannot be transmitted through food. Eating chicken, thus, does not pose any problems in this respect. Nevertheless, the European Union has vowed that it is about to take preventive measures, by banning the import of chicken meat and products from Thailand, seeking to prevent any infected birds from getting into European countries.
Q: What are the actions taken to put an end to the infection prevalence in the countries affected by avian influenza?
A: Millions of birds have been culled, in pursuit of put an end to the infection prevalence among birds, thus preventing it from transmission to humans.
Conclusion:
The Upcoming Pandemic: Resistible?!
It is now some thirty-six year since the last global pandemic befell the world, and many experts tend to believe that the occurrence of a new pandemic is rather inevitable and unavoidable. Although the pandemic severity could not be foreseen, it universally acknowledged that the emergence of a pandemic without preventive drugs means that it will be sweeping, devastating pandemic.
It is expected that the epidemic will last for a long span of time, in the form of epidemiological attacks at certain intervals, just as was the case with the former pandemics. One of the haunting challenges, also, is that there will not be sufficient resources (medical requirements, health cadres, etc.) to fight the pandemic, making infection control just improbable. Consequently, the world should be fully prepared for handling any probabilities, even if a comprehensive world pandemic, Allah forbid! This necessitates all countries cooperate and work hand in hand, and pay every attention to the prevention or reduction of H5N1 infection.
During the past century, indisputable pandemics of influenza occurred in 1918, 1957 and 1968, with significant morbidity and mortality in both high risk and normal children and adults. These pandemics tend to occur at unpredictable intervals, while epidemics tend to occur more frequently (every 1-3 years) with varying degrees of severity. There appear to be no patterns of influenza illness that allow one to predict the occurrence of the next epidemic or pandemic. All one can say is that as each year passes, we get one year closer to the next pandemic.
In the 1918 pandemic, while the highest death rates occurred in infants and older individuals, the greatest absolute numbers of deaths occurred in the 20-39 year old age group. This would translate into 760,000 deaths among the 20-39 year olds in today's population. Because of the rapid spread of a future influenza pandemic due to changes in worldwide transportation and commerce we must be prepared globally to provide sufficient supplies of vaccine and be organized enough to administer these vaccines to as many people as possible.
With this in mind, the relevant health authorities have to set a comprehensive plan on how to fight a world pandemic. And this plan has to be immediately activated to monitor and control H5N1 infection. Besides, authorities have to be decisive with any infection outbreaks among poultry, as well as treating and quarantining any human avian cases. That is to be added to the close follow-up of the world health situation and take similar measures to those taken on the prevalence of SARS outbreak: medically examining incomers, and keeping an eye on those suffering from high temperature or respiratory symptoms.
Since the Kingdom of Saudi Arabia is located in the health of the world, and receives every year over 2.000.000 pilgrims coming from everywhere, including the countries stricken by avian influenza such as Indonesia and China, the Kingdom may have to close all its borders against incomers, and confine Hajj to Saudis.
References:
- World Health Organization (WHO), Reports and Publications (2003 – 2005).
- Center of Disease Control (CDC), USA.