‘Swine Influenza A (H1N1) Virus Infection’ :

Prevention is better than cure

Dr. Lohitha Samarawickrema

Prevention is Better than Cure. The ancient saying, says it all. As a nation we must look out for the epidemic outbreaks in the world and take precautions well in advance to prevent such disastrous penetrations to our country.

Swine Influenza (Swine Flu) is one of the epidemics reported in USA and Mexico, Canada, Israel name the few out of the 11 countries reported, will have a greater possibility of attacking the whole world, if preventive measures are not taken.

It is our responsibility to educate and provide information to guide the general public to eradicate such disastrous epidemics which affects our people’s lives, country’s productivity and the economy which is not an affordable acceptance to our country at this juncture.

Furthermore at the very edge of eradication of Terrorism in the country, we must be even more careful of these epidemic viruses as these may be used to harm the society by the terrorists in the form of biological weapons, as the world has had similar experiences like Anthrax fear in the past.

SARS (Severe Acute Respiratory Syndrome) was another epidemic which took just more than 700 lives in 37 countries in the recent past. Considering the effects for the swine industry or any other indirect economic factors and panic situations of the public, the world authorities are reluctant to light up information about epidemic outbreaks often.

Swine influenza is a respiratory disease of pigs caused by type A influenza viruses and has a major economic impact on the swine industry in the world.

Flu outbreaks in pigs are common, especially during winter months. Swine flu can result in high rates of illness in herds. Signs of swine flu in pigs are some what very much similar to humans.

Studies have shown that 30% to 50% of commercial U.S. swine have been infected with swine flu. Pigs most commonly get infected with flu viruses from other pigs (swine flu), but also can get infected with flu viruses from birds (avian flu), and from people (human flu).

This cross-species spread of flu viruses can lead to new types of flu viruses. The number of subtypes and strains of flu virus circulating among herds has complicated swine flu vaccine programs and resulted in increased economic loss from illness in pigs.

Veterinary surgeons can help to develop management strategies to reduce the spread of flu among herds and to prevent the spread of flu viruses between pigs, people, and birds.

Swine flu in humans

To date, human cases of swine influenza A (H1N1) virus infection have been confirmed in residents of California, Texas, and Mexico. It is also reported several cases in Spain, Israel and New Zealand increasing the death toll to 159 among over 2500 infected so far. WHO - Geneva has stepped up state of alert level to phase 5 is yet to increase.

Illness signs and symptoms have consisted of influenza-like illness - fever and respiratory tract illness (cough, sore throat, runny nose), headache, muscle aches - and some cases have had vomiting and diarrhoea. These cases had illness onset during late March to mid-April 2009.

However, cases of severe respiratory disease, including fatal outcomes, have been reported increasing the numbers by date. The potential for exacerbation of underlying chronic medical conditions or invasive bacterial infection with swine influenza virus infection should be considered.

The swine influenza A (H1N1) virus that has infected humans in the U.S. and Mexico is a novel influenza A virus that has not previously been identified in North America. This virus is resistant to the antiviral medications amantadine and rimantadine, but is sensitive to oseltamivir and zanamivir.

Investigations of these cases suggest that on-going human-to-human swine influenza A (H1N1) virus is occurring. After all the question arises, whether swine influenza A be transmitted through food.

There is no evidence to show that swine influenza can be transmitted through food. Eating properly handled and cooked pork and pork products are safe. Cooking pork to an internal temperature of 160°F kills bacteria and viruses.

Infectious period

Persons with swine influenza A (H1N1) virus infection should be considered potentially contagious for up to 7 days following illness onset. Persons who continue to be ill longer than 7 days after illness onset should be considered potentially contagious until symptoms have resolved.

Children, especially younger children, might potentially be contagious for longer periods. The duration of infectiousness might vary by swine influenza A (H1N1) virus strain.

Non-hospitalized ill persons who are a confirmed or suspected case of swine influenza A (H1N1) virus infection are recommended to stay at home (voluntary isolation) for at least the first 7 days after illness onset except to seek medical care.

A confirmed case of swine influenza A (H1N1) virus infection is defined as a person with an acute respiratory illness with laboratory confirmed swine influenza A (H1N1) virus infection by one or more of the following tests: “RT-PCR (Real Time) (In fact, this technique is sensitive enough to enable quantisation of RNA from a single cell.) “viral culture” four-fold rise in swine influenza A (H1N1) virus-specific neutralizing antibodies A suspected case of swine influenza A (H1N1) virus infection is defined as a person with acute febrile respiratory illness with onset within 7 days of close contact (Close contact is defined as: within about 6 feet of an ill person who is a confirmed or suspected case of swine influenza A (H1N1) virus infection) with a person who is a confirmed case of swine influenza A (H1N1) virus infection.

Interim recommendations

Personnel engaged in aerosol generating activities (e.g., collection of clinical specimens, endotracheal intubation, nebulizer treatment, bronchoscopy, and resuscitation involving emergency intubation or cardiac pulmonary resuscitation) for suspected or confirmed swine influenza A (H1N1) cases should wear a fit-tested disposable respirator.

Pending clarification of transmission patterns for this virus, personnel providing direct patient care for suspected or confirmed swine influenza A (H1N1) cases should wear a fit-tested disposable respirator when entering the patient room.

Staff should be medically cleared, fit-tested, and trained for respirator use, including: proper fit-testing and use of respirators, safe removal and disposal, and medical contraindications to respirator use. Most importantly the Public / Animal Health officials have a major role to play. Officials should conduct thorough case and contact investigations to determine the source of the swine influenza virus, extent of community illness and the need for timely control measures.

Infection Control of Ill Persons in a Healthcare Setting Patients with suspected or confirmed case-status should be placed in a single-patient room with the door kept closed. If available, an airborne infection isolation room (AIIR) with negative pressure air handling with 6 to 12 air changes per hour can be used.

Air can be exhausted directly outside or be recirculated after filtration by a high efficiency particulate air (HEPA) filter. For suctioning, bronchoscopy, or intubation, use a procedure room with negative pressure air handling.

The ill person should wear a surgical mask when outside of the patient room, and should be encouraged to wash hands frequently and follow respiratory hygiene practices. Cups and other utensils used by the ill person should be washed with soap and water before use by other persons.

Routine cleaning and disinfection strategies used during influenza seasons can be applied to the environmental management of swine influenza.

Standard, Droplet and Contact precautions should be used for all patient care activities, and maintained for 7 days after illness onset or until symptoms have resolved. Maintain adherence to hand hygiene by washing with soap and water or using hand sanitizer immediately after removing gloves and other equipment and after any contact with respiratory secretions.

Personnel providing care to or collecting clinical specimens from suspected or confirmed cases should wear disposable non-sterile gloves, gowns, and eye protection (e.g., goggles) to prevent conjunctival exposure.

Acute respiratory illness is defined as recent onset of at least two of the following: rhinorrhea or nasal congestion, sore throat, cough (with or without fever or feverishness) Clinicians should consider swine influenza A (H1N1) virus infection in the differential diagnosis of patients with febrile respiratory disease and who 1) live in San Diego and Imperial Counties, California, or Guadalupe County, Texas, or travelled to these counties or 2) who travelled recently to Mexico or were in contact with persons who had febrile respiratory illness and were in the two U.S.

Counties or Mexico in the 7 days preceding their illness onset.