Agriculture Business Week

Along with the dreaded Influenza A(H1N1) virus, misconception on the virus have also been spreading,. We hope we can dispel some of these and give our readers real information instead of hype.

Misconception No. 1. The current flu outbreak is being spread by pigs.
Fact: Even if pigs were the original source of the disease, experts from the World Health Organization (WHO), Office International des Epizooties (OIE) or World Organization for Animal Health and Centers for Disease Control and Prevention (CDC) said swine did not appear to be playing any role in its transmission now. The virus is passing from person to person, most likely by the spread of respiratory droplets. Influenza, let us remember, is a respiratory disease, thus coughing and breathing may provide an aerosol release of virus to the air and surfaces for transmission.

Misconception No. 2. Influenza A is a foodborne infection.
Fact: The new strain of influenza virus is not transmitted by food. You cannot get the new viral infection by eating pork, bacon, or other foods that came from pigs. Eating properly handled and cooked pork and pork products is safe. Cooking pork to an internal or core temperature of 70°C or,, 160′F kills the flu virus as it does other bacteria and viruses.

Misconception No. 3. Travel restrictions and border closures are effective means of preventing the spread of influenza A (H1N1).
Fact: Although the WHO has been very clear in asserting that it does not recommend travel restrictions to or from any country or between any locations, several countries have already issued travel restrictions and/or advisories. While this may seem a sensible measure, there is no evidence to indicate that such restrictions effectively limit the spread of disease.

Historically speaking, closing airports and screening travelers at borders have not been effective in preventing the ingress of disease. In its historical analysis of previous influenza pandemics, the WHO concluded that “screening and quarantining entering travelers at international borders did not substantially delay virus introduction in past pandemics… and will likely be even less effective in the modern era.”

Misconception No. 4. Reliable methods such thermal screens are available for rapid screening. Fact: There is no reliable way to rapidly determine if someone has influenza A at the borders or anywhere else. Currently, the symptoms of H1N1 flu are not easily distinguishable from other common diseases, such seasonal flu and other respiratory infections. There are no rapid clinical tests that can conclusively determine on-site if an individual has influenza A. In fact, at this point, confirmation of swine flu requires sophisticated analyses beyond general screening for influenza or influenza-like illness.

How about the use of thermal screens to detect infected individuals?

There is little, empirical evidence that thermal screens, which rapidly measure a person’s temperatures, will be effective. The use of thermal screens has already been proposed and in some locations has been in use as the method for rapid screening to identify infected individuals in airports and hospital entries. There are questions about the accuracy of any technology that attempts to assess fever by measuring skin temperature, including “sophisticated imaging” techniques such as the large thermal scanners that are deployed in some international airpolls.

In one published study, infrared thermal devices which measure the temperature of an individual’s skin were found to be poor predictors of whether an individual actually has a fever. According to the study, the infrared tool correctly ruled out fever among 99 percent of individuals who did .not have fever based on measurement of core temperature, but it correctly identified fever in only 10 percent of patients. The accuracy of the skin-temperature based devices also varies with regard to the degree of an individual’s age and fever and the outdoor temperature. Consequently, the authors conclude that measuring a patient’s skin temperature with an infrared device does not reliably detect fever.

There are also biological reasons why rapid methods of screening for fever are not reliable way to detect if an individual is infectious, and among these are the following:

a. Most rapid fever screeners measure sure skin temperature, which has been found to be a poor predictor of actual body temperature.
b. Fever is not a constant phenomenon during an infection.
c. Medications commonly taken by sick individuals may reduce fever.

Misconception No. 5. The current A (H1N1) outbreak is the result of bioterrorism.
Fact: During the press briefing of the Department of Homeland Security (DHS), CDC, and White House on April 26, 2009, a reporter asked if the current influenza A outbreak is a naturally occurring event or evidence of bioterrorism (intentional release or dissemination of biological agents such as bacteria, viruses, or toxins) as the swine flu virus is composed of portions of virus from multiple sources (pigs, birds, and humans). Understanding how a virus can have multiple sources naturally is important to understanding why this is not bioterrorism. Genetic analysis clearly indicates that this hybrid virus is the product of genetic reassortment, a natural phenomenon of shuffling genes that occurs frequently with influenza or flu viruses and is the cause of all influenza, pandemics (the Spanish flu in 1918, the Asian flu in 1957, and the Hong Kong flu in 1968). It is not at all likely that the current outbreak is the result of bioterrorism.

This ability to shuffle genes is unique to influenza, according to the Center for Biosecurity of the University of Pittsburgh Medical Center, an integrated global health enterprise headquartered in Pittsburgh, Pennsylvania, and one of the leading nonprofit health systems in the United States. It occurs because the influenza virus has a segmented genome. Meaning, it is composed of eight pieces of RNA (ribonucleic acid) that are not connected. When a host whether pig, bird, or human becomes infected simultaneously with two different influenza viruses for example, a swine influenza virus and a seasonal human influenza virus a new virus can be formed that has a combination of genes from the two parent viruses. As assembled within the infected cell, mixing of the viral RNA segments can occur; some segments of the genetic material (RNA) from one virus may become incorporated into the other virus’s packaging. Thus, a new influenza virus is created with components of 2 different viruses.

The current swine flu virus appears to have genes from different swine virusesand possibly human and avian viruses. Some genes are similar to North American swine influenza viruses, while others are from viruses isolated fom Eurasian pigs. At some point in the past, it is likely that a co-infection (or co-infections) occurred to allow the mixing of different viruses and the swapping of genetic elements. Even though the swine flu appears to have disparate origins, the virus is labeled as “swine flu” because most components are of swine origin.

In the future, there may be scientific disagreement about the exact origins of each segment in swine flu, but its mixed genetic origin is a hallmark. of naturally evolving influenza viruses, not bioterrorism.

Misconception No. 6. The flu shot can give you the flu.
Fact: Flu shot cannot cause flu illness. Each of the three influenza viruses contained in the flu vaccine are inactivated (killed), which means they cannot cause infection. Flu vaccine manufacturers kill the viruses used in the vaccine during the process of making vaccine, and batches of flu vaccine are tested to make sure they are safe. In randomized, blinded studies, where some people get the flu shots and others get salt-water shots, the only differences in symptoms were increased soreness in the arm and redness at the injection site among people who get the flu shot. There were no differences in terms of body aches, fever, cough, runny nose, or sore throat.

Misconception No. 7. Influenza A is severe for young adults. Fact: Health Secretary Francisco T. Duque III said that “right now, what we’re seeing from the behavior of the virus is that most of the cases are mild and are self-limiting. The case fatality rate of H1N1, in fact is less than 1 percent. Dengue is even more fatal in the country where we now have 57 deaths as of April this year.”

“The most important thing is that we still do not have any severe cases or any death,” Duque added. There is no indication also that there is already sustained community transmission in the Philippines.”