Bird flu virus spreads to six South Sulawesi regencies

Bird Flu Virus Spreads

Avian flu outbreak has affected six South Sulawesi regencies, where 18,000 chickens have died suddenly.

Head of the provincial husbandry agency Murtala Ali said on Thursday the infection had spread across the regencies of East Luwu, North Luwu, Pinrang, Soppeng, Sidenreng Rappang and Bone since September. He added that infection also was also reported in Barru regency.

Murtala said the first case of infection was found in East Luwu.and quickly affected the neighboring regency of North Luwu. The local authorities were forced to cull some of the chickens in order not to infect other fowls.

The agency has also sprayed disinfectant and conduct vaccination in areas where infection was found.

Murtala said the changing weather pattern was likely blamed for revival of the bird flu virus.

“The virus’ survival is very much dependant on the weather. This extreme change of weather may have triggered the outbreak,” Murtala said, adding that the high mobility of chickens had accelerated the spread of the virus.

Meanwhile, four people who were admitted to Wahidin Sudirohusodo Hospital in Makassar on Sept. 29 for displaying symptoms of bird flu infection have all tested negative for the virus.

General affairs director of the hospital Kalsum Patonangi said Thursday the four patients had been discharged.

New Mechanism of Bird Flu Virus Transmission

Scientists Discover

A new way of avian influenza circulation and transmission has been discovered by American researchers.

Led by Mauro Delogu, virologist from the Veterinary Faculty of the Bologna University and researchers from the Istituto Superiore di Sanita, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia and St. Jude Children's Research Hospital (Memphis, Tennessee), the study offers new insights into ecology, surveillance and prevention strategies of avian influenza viruses (AIVs).

And the research could ultimately be important in the fight against influenza.

The scientists actually discovered that the preen oil gland secretions, by which all aquatic birds make their feathers waterproof, support a natural mechanism that concentrates AIVs from water onto birds' bodies.

They found that a progressive virus "sticking" on feathers occurs because AIV-contaminated waters interact with the preen oil gland secretion.

Since waterbirds use to spread preen oil over their own (self-preening) or other birds' (allo-preening) plumage, it is easily understandable how these preening activities could facilitate the diffusion of the viruses in nature.

The discovery has also important implications in the surveillance of avian influenza viruses, added Delogu.

In fact, virus on feathers could escape detection by the current surveillance strategies, which assay the virus secreted in the cloacal and tracheal samples only.

Lack of detection of these viruses may greatly complicate surveillance and rapid responses to new virus emergence and spread.

For this reason in routine surveillance programs, additional sampling methods could be necessary to detect AIVs on birds' bodies, said Delogu.

Vaccination as Part of an Avian Influenza Control Strategy

Introduction Influenza Control Strategy

Avian influenza is a disease capable of causing extremely high mortality amongst infected poultry. Influenza viruses have a worldwide distribution and although not endemic in commercial poultry sporadic outbreaks do occur.

In recent times these outbreaks have been occurring with increasing regularity. Outbreaks are typically of a low pathogenic form of avian influenza (LPAI). Past experience indicates that in a susceptible domestic poultry population, circulating LPAI (especially H5- and H7- subtypes) has the ability to mutate into a more devastating high pathogenic avian influenza (HPAI) resulting in Fowl Plague.

HPAI is an OIE List A disease, hence the accepted control measure is implementing a "stamping out" procedure. All poultry that are infected, suspected of being infected or suspected of being contaminated are culled. This is accompanied by severe restrictions on the movement of poultry, personnel and related industry activities within the designated quarantine area. However in areas with high poultry density these stringent control measures may not be sufficient in curtailing the spread of the virus as has been experienced with the current HPAI outbreak in The Netherlands.

During a nine-week period (01/03/2003 . 02/05/2003) the virus has spread from an initial outbreak involving six poultry farms to a total of 243 confirmed cases, with new cases being confirmed daily. This is despite culling more than 21 million poultry during this time period and all efforts at strictly controlling movement within the industry. With the virus now jumping the border into Belgium questions must be asked whether there are not more effective strategies to control such an epidemic. 

Avian Influenza Vaccination

Vaccination as an additional control tool has been used with success in controlling LPAI⁵ outbreaks as well as HPAI outbreaks in the past (1995 - Utah, USA; 2000 - Italy³ & California, USA; 2001 - Hong Kong; 2002 - Colorado, USA). At the Fifty-Second Western Poultry Disease Conference held in Sacramento, California during March 2003 Capua and Marangon² proposed a scheme, summarised in Diagram 1, whereby vaccination is included in the control strategy in certain scenarios.

The concept of vaccination in the face of HPAI is however met with much resistance based on the arguments that it is not in line with OIE or EU control strategies, would have an negative impact on export trade agreements and potentially masks the symptoms of the disease thus removing the most significant early warning signal for HPAI - acute increase in mortality. 

Trade Regulations

As a list A disease (OIE) an HPAI outbreak has serious trade implications, such as a possible export ban on poultry products. The document International Animal Health Code (2002) of the office International des Epizooties (OIE) defines a country as HPAI free:

·         when it has been shown that HPAI has not been present in the country for the past 3 years, or

·         six months after the slaughter of the last affected animal for countries in which a stamping-out policy is practised with or without vaccination.

Claiming this free status is achieved by the lack of fresh outbreaks and sufficient proof that repopulated flocks remain AI seronegative. AI vaccinated flocks test seropositive, thus effectively complicating the surveillance required to declare a region free of HPAI. However, by vaccinating with a heterologous vaccine and applying the DIVA (Differentiating Infected from Vaccinated Animals) monitoring strategy it is possible to demonstrate that there is no circulating virus in the vaccinated population. This principle was successfully used to lift trade bans in Italy during the 2000 Italian AI outbreak.

Commission Decision of 30 November 2001 amending for the third time to modify the Italian avian influenza vaccination programme and current trade restrictions for fresh meat originating from vaccinated turkeys.

DIVA Strategy

The DIVA strategy4 is based on the use of an inactivated oil emulsion vaccine containing the same haemagglutinin (H) subtype as the field virus, but a different neuramidase (N). The homologous H group ensures protection while it is possible to differentiate vaccinated from infected birds based on the serological response to the N group using an indirect immunofluorescence test. Vaccinated birds should only test positive to the N group used in the vaccine, a positive reaction to the N group of the prevailing infective virus would indicate a field challenge. 

Reduction of Virus Excretion

What is the advantage of vaccination? The most significant benefit of vaccination is the dramatic reduction in virus shedding from infected birds, reducing the load of environmental contamination and consequently containing the spread of the virus. In a published article by Swayne et. al.6, SPF chickens vaccinated at day old or 3 weeks of age with an inactivated whole AI vaccine (H5N2) were challenged 4 weeks later with the HP A/Hong Kong/156/97 (H5N1) influenza virus. Two days post challenge Swayne demonstrated a reduction in the re-isolation rate of the challenge strain from vaccinated birds in comparison to unvaccinated controls. Of more significance though was a significant reduction in the titre of virus re-isolated from vaccinated chickens in comparison to unvaccinated controls.

Diagnosis

How to Recognise Avian Influenza

What to look for

·         Ruffled feathers

·         Soft-shelled eggs

·         Depression and droopiness

·         Sudden drop in egg production

·         Loss of appetite

·         Cyanosis (purplish-blue coloring) of wattles and comb

·         Edema and swelling of head, eyelids, comb, wattles, and hocks

·         Green diarrhoea

·         Blood-tinged discharge from nostrils

·         Incoordination, including loss of ability to walk and stand

·         Pin-point hemorrhages (most easily seen on the feet and shanks)

·         Respiratory distress

·         Increased death losses in a flock

·         Sudden death

·         Nasal discharges

Avian influenza Outbreaks

Outbreaks of avian influenza in the poultry industry cause devastating economic losses and is generally controlled through extensive culling of infected birds. Alternative strategies also use vaccination as a supplementary control measure during avian influenza outbreaks.

Advantages of Vaccination

·         Vaccination reduces susceptibility to infection.

·         A higher dose of virus is necessary to infect the vaccinated birds.

·         Vaccinated birds shed less virus.
- Decreased contamination of the environment.
- Decreased risk of human infection

·         Used strategically vaccination compliments a stamping out strategy by slowing/stopping the spread of the virus

TREATMENT AND VACCINATION FOR H5N1 VIRUS IN HUMANS

Recommendations from management aspects

The H5N1 virus that was found to be major cause of human illness and death in Asia is resistant to amantadine and rimantadine, two antiviral medications commonly used for influenza. Two other antiviral medications, oseltamavir and zanamavir, would probably work to treat influenza caused by H5N1 virus, but additional studies still need to be done to demonstrate their safety and effectiveness.Treatment modalities recommended for the clinical management of human H5N1 virus infection is shown in table.

When there is evidence for sustained human-to-human transmission of H5N1 or another novel avian influenza virus emerges, strict recommendations need to be developed. Whenever feasible, sequential clinical data collection and virological sampling (for analysis at WHO-designated laboratories) should be performed during treatment or should apparent failures of chemoprophylaxis occur. Self-medication in the absence of appropriate clinical or public health advice is discouraged. When considering chemoprophylaxis for H5N1 infection, priority should be given to standard infection control practices. This includes protection of health care workers and individuals involved in eradication of animals infected with H5N1 virus as well as household contacts of H5N1 patients.

For treatment of patients with confirmed or strongly suspected human infection with the H5N1 virus, where neuraminidase inhibitors are available for therapy:

Clinicians should administer oseltamivir treatment (strong recommendation); zanamivir might be used as an alternative (weak recommendation).
In these patients, clinicians should not administer amantadine or rimantadine alone as a first-line treatment (strong recommendation).

Clinicians might administer a combination of a neuraminidase inhibitor and an M2 inhibitor if local surveillance data show that the H5N1 virus is known or likely to be susceptible (weak recommendation), but this should only be done in the context of prospective data collection.

For treatment of patients with confirmed or strongly suspected H5N1 infection, where neuraminidase inhibitors are not available for therapy:

Clinicians might administer amantadine or rimantadine as a first-line treatment if local surveillance data show that the H5N1 virus is known or likely to be susceptible to these drugs (weak recommendation).
In general, decisions to initiate antiviral chemoprophylaxis should be guided by the risk stratification described below. Stratification is based on observational data for reported cases of human H5N1 infection and on high quality data from studies of seasonal influenza.

High risk exposure groups are currently defined as:

• Household or close family contacts of a strongly suspected or confirmed H5N1 patient, because of potential exposure to a common environmental or poultry source as well as exposure to the index case.

Moderate risk exposure groups are currently defined as:

• Personnel involved in handling sick animals or decontaminating affected environments (including animal disposal) if personal protective equipment may not have been used properly.
• Individuals with unprotected and very close direct exposure to sick or dead animals infected with the H5N1 virus or to particular birds that have been directly implicated in human cases.
• Health care personnel in close contact with strongly suspected or confirmed H5N1 patients, for example during intubation or performing tracheal suctioning, or delivering nebulised drugs, or handling inadequately screened/sealed body fluids without any or with insufficient personal protective equipment. This group also includes laboratory personnel who might have an unprotected exposure to virus containing samples.

Low risk exposure groups are currently defined as:

• Health care workers not in close contact (distance greater than 1 metre) with a strongly suspected or confirmed H5N1 patient and having no direct contact with infectious material from that patient.
• Health care workers who used appropriate personal protective equipment during exposure to H5N1 patients.
• Personnel involved in culling non-infected or likely non-infected animal populations as a control measure.
• Personnel involved in handling sick animals or decontaminating affected environments (including animal disposal), who used proper personal protective equipment.

Where neuraminidase inhibitors are available:

• In high risk exposure groups, including pregnant women, oseltamivir should be administered as chemoprophylaxis, continuing for 7–10 days after the last exposure (strong recommendation); zanamivir could be used in the same way (strong recommendation) as an alternative.
• In moderate risk exposure groups, including pregnant women, oseltamivir might be administered as chemoprophylaxis, continuing for 7-10 days after the last exposure (weak recommendation); zanamivir might be used in the same way (weak recommendation).
• In low risk exposure groups oseltamivir or zanamivir should probably not be administered for chemoprophylaxis (weak recommendation). Pregnant women in the low risk group should not receive oseltamivir or zanamivir for chemoprophylaxis (strong recommendation).
• Amantadine or rimantadine should not be administered as chemoprophylaxis (strong recommendation).

Where neuraminidase inhibitors are not available:

• In high or moderate risk exposure groups, amantadine or rimantadine might be administered for chemoprophylaxis if local surveillance data show that the virus is known or likely to be susceptible to these drugs (weak recommendation).
• In low risk exposure groups, amantadine and rimantadine should not be administered for chemoprophylaxis (weak recommendation).
• In pregnant women, amantadine and rimantadine should not be administered for chemoprophylaxis (strong recommendation).
• In the elderly, people with impaired renal function and individuals receiving neuropsychiatric medication or with neuropsychiatric or seizure disorders, amantadine should not be administered for chemoprophylaxis (strong recommendation).

We recommend that countries develop their own guidelines for the assessment of human patients in whom there is a suspicion of influenza A (H5N1) infection. These should include the criteria required to initiate treatment pending confirmatory laboratory testing. Such guidelines will reflect geographical location with respect to recent outbreaks of avian influenza H5N1 in birds and the locally available resources.

SELF-CARE GUIDELINES

Self Medication

To prevent avian influenza:

• If you are in an area where avian influenza is a risk, protect yourself by practicing good hand hygiene.
• If you will be handling birds known or thought be infected, protect yourself with gloves, goggles, a medical gown, shoe covers, and a mask designed for very small particles, such as a tuberculosis mask.
• There is little known about transmission of avian influenza between humans, but to be on the safe side, do not allow secretions, sneezing, or coughing to contaminate other humans, particularly children, the elderly, and the immunocompromised.

When to Seek Medical Care Contact your doctor for any illness with high fever (ie, temperature greater than 39°C [102°F]), inability to tolerate foods or liquids, or bad abdominal pain.

TREATMENTS YOUR PROVIDER MAY PRESCRIBE

Treatment for Avian Influenza





There is no certain treatment for avian influenza. Some drugs (antivirals) that are used to treat human influenza may be helpful for patients with avian influenza, but for both, these drugs are designed to shorten the duration and severity of symptoms; the illness must run its course. The earlier in the course of illness these drugs are started, the better. If one person in a family develops avian influenza, the other family members may receive an antiviral in order to protect against illness (although at this time the disease is not thought to be contagious person to person). There is a specific vaccine for one strain of avian influenza; the vaccine will be made available to the public in the event of an outbreak. The human influenza vaccine that the Centers for Disease Control and Prevention makes public every year does not protect against avian influenza.