Avian Influenza

Prevention and Control of Influenza due to Avian Influenza Virus A (H5N1)

      Potential for an Influenza Pandemic

All influenza viruses have the potential to can change. It is possible that an avian influenza virus could change so that it could infect humans and could spread easily from person to person. Because these viruses do not commonly infect humans, there is little or no immune protection against them in the human population. If an avian virus were able to infect people and gain the ability to spread easily from person to person, an “influenza pandemic” could begin. An influenza pandemic is a global outbreak of influenza and occurs when a new influenza virus emerges, spreads, and causes disease worldwide. Past influenza pandemics have led to high levels of illness, death, social disruption and economic loss. There were 3 pandemics in the 20th century. All of them spread worldwide within 1 year of being detected. They are:

The Spanish Flu is considered the most severe of all influenza outbreaks till date. Though the identification of aetiology of the pandemic was not possible at that time, modern day molecular biological techniques have tried to unravel its mystery. Modern techniques have permitted a reconstitution of some parts of the genome of the 1918 agent by amplifying fragments of viral RNA obtained from different sources. One of them was anatomopathologic samples of lungs from patients who died of the disease in 1918. Other samples were obtained after the exhumation of victims of Spanish flu in Alaska and in Svalberg whose bodies had been buried in permafrost ground. Genetic sequences were obtained by genic amplification of viral RNA extracted from the lung fragments and were compared to recent human and animal viruses. The comparison showed that the hemagglutin of the 1918 virus was of the H1 subtype belonging to a subgroup of strains infecting human and pigs, but also sharing avian determinants. Sequence analysis indicates that many avian characteristics are present in critical locations of the hemagglutinin gene such as receptor, antigenic and glycosylation sites suggesting an avian relationship. However, the virus is closely related to human and swine viruses. Equivalent findings were obtained from the study of the neuraminidase gene : the enzymatic site is preserved but avian characteristics are found in antigenic and glycosylation sites. These results suggest that the 1918 virus borrowed determinants from avian strains but was already present in mammals for a prolonged period before the pandemic started

      ADVICE TO INTERNATIONAL TRAVELLERS

So far WHO has not issued any travel alerts or advisories for the region in response to the H5N1 outbreak. However, travellers to countries in Asia with documented H5N1 outbreaks are advised to avoid poultry farms, contact with animals in live food markets and any surfaces that appear to be contaminated with faeces from poultry or other animals.

      INFECTION CONTROL PRACTICES

These are similar to those required for infectious respiratory pathogens and were practised for SARS containment during 2002-2003.. Management of avian influenza cases will depend on assigning proper isolation areas in the hospital, barrier nursing and stocking PPE and availability of other essential supplies and materials. This will require advance planning.

      PERSONAL PROTECTIVE EQUIPMENT (PPE) AND THEIR USE

In all cases, following principles apply:

     PPE reduces but does not completely eliminate the possibility of infection.

     PPE is only effective if used correctly and at all times where contact may occur.

     Any contact between contaminated (used) PPE and surfaces / clothing / people outside the isolation area must be avoided.

     Used PPE must be sealed in appropriate disposal bags and sterilized or decontaminated. If staff temporarily leave the isolation area, a complete change of PPE and hand washing required.

     The use of PPE does not replace basic hygiene measures such as hand-washing, washing is still essential to prevent transmission.

     Exposure to the infected patient should be kept to an absolute minimum necessary for the level of care required.

Who should use PPE?

The staff team assigned to care for the patient should be kept to a minimum. Staff should be strictly supervised and be experienced in infection control. PPE should be used by:

     All those who are handling infected or suspected to be infected poultry and poultry products. These include cullers and animal husbandry/veterinary staff.

     All doctors, nurses and health care workers who provide direct patient care to avian influenza cases (keep to minimum necessary for patients' condition);

     All support staff including medical aides, X-ray technicians, cleaners, transport staff, laundry staff (keep staff to the minimum necessary, designate avian influenza laundry staff, etc.);

     All laboratory staff who handle patient specimens from suspect cases (keep to the minimum the staff necessary for laboratory procedures);

     Family members who care for avian influenza patients (visits should be avoided where possible);

     The patient(s) should wear a mask (N95 preferable) when other people are in the isolation area.

     Contacts and international travellers during home isolation/quarantine must wear a mask (N95 preferable).

Personal Protective Equipment

The items included are:

     Masks (N-95; N/P/R-100, If not available N80 or surgical masks as last resort)

     Gloves

     Gloves and aprons

     Hair Covers

     Eye protective ware (goggle)

     Boots or shoe covers

Storage / positioning of the supplies

     The PPE stock should be stored where it can be readily accessed at all times (24 hours a day), and is available for despatch to a facility/transport where suspected influenza patients are involved.

     The stock must be accessible after hours and on weekends.

Hand washing

It is the single most important and effective component for preventing the transmission of infection. Running water and soap with friction should be ideally used for 15 to 20 seconds. It is important to dry hands after washing. A 70% alcohol-based hand rub solution after hand washing can be used.

Hand washing  should be done:

     After removing gloves

     Before and after patient contact or contact with potentially infected material

     After contact with blood and body fluids

     After taking samples

     After taking blood pressure or vital signs from patient

     After using bath room

     After blowing/wiping nose

     Before eating and preparing food.

     When leaving the isolation unit.

Linen handling

     Designated laundry staff should put patient’s linen in bags and seal in the isolation room itself.

     Laundry staff should wear full PPE.

     Washing should be done in laundry with hot water and detergent, bleach may be added if compatible with the detergent being used.

Waste disposal

The practices as approved by the Hospital Infection Control Committee or hospital authorities must be followed. Some of these are:

     Puncture proof and leak proof containers should be used for sharps.

     Waste should be collected in designated colour coded plastic bags for sterilization and disposal.

     Double bag system for transport should be used.

Cleaning and disinfection of hospital environment and equipment

The practices as approved by the Hospital Infection Control Committee or hospital authorities must be followed. Some of these are:

     Cleaning staff should wear full PPE

     Cleaning  should be done thoroughly to be followed by disinfection

     Isolation, X-ray and changing rooms should be cleaned and disinfected

     Items and areas requiring cleaning and disinfection are:

     Bedside table, bed stand, accessible areas of bed and floors (Use 0.1% sodium hypochlorite as disinfectant)

     If any surface is grossly contaminated, pour 1% sodium hypochlorite first and leave it for 10-15 minutes to be followed by cleaning and usual disinfection (0.1% sod. hypochlorite).

     Basins and bedpans should be cleaned and disinfected before being used for another patient.

     Spray disinfectant is prohibited.

      PATIENT, FAMILY AND COMMUNITY EDUCATION

Education for the patient, their family, contacts at home isolation and the community is essential for control and prevention of avian influenza.

Education should be imparted on

      What avian influenza is and how it is transmitted.

      Why isolation is required for a case/contact of influenza

      Precaution required including PPE and how to wear N-95 mask.

      Hand washing procedure