Swine flu (swine influenza) is a respiratory disease caused by viruses (influenza viruses) that infect the respiratory tract of pigs and result in nasal secretions, a barking-like cough, decreased appetite, and listless behavior. Swine flu produces most of the same symptoms in pigs as human flu produces in people. Swine flu can last about one to two weeks in pigs that survive. Swine influenza virus was first isolated from pigs in 1930 in the U.S. and has been recognized by pork producers and veterinarians to cause infections in pigs worldwide. In a number of instances, people have developed the swine flu infection when they are closely associated with pigs (for example, farmers, pork processors), and likewise, pig populations have occasionally been infected with the human flu infection. In most instances, the cross-species infections (swine virus to man; human flu virus to pigs) have remained in local areas and have not caused national or worldwide infections in either pigs or humans. Unfortunately, this cross-species situation with influenza viruses has had the potential to change. Investigators think the 2009 swine flu strain, first seen in Mexico, should be termed novel H1N1 flu since it is mainly found infecting people and exhibits two main surface antigens, H1 (hemagglutinin type 1) and N1 (neuraminidase type1). Recent investigations show the eight RNA strands from novel H1N1 flu have one strand derived from human flu strains, two from avian (bird) strains, and five from swine strains.

Why is swine flu (H1N1) now infecting humans?

Many researchers now consider that two main series of events can lead to swine flu (and also avian or bird flu) becoming a major cause for influenza illness in humans.

First, the influenza viruses (types A, B, C) are enveloped RNA viruses with a segmented genome; this means the viral RNA genetic code is not a single strand of RNA but exists as eight different RNA segments in the influenza viruses. A human (or bird) influenza virus can infect a pig respiratory cell at the same time as a swine influenza virus; some of the replicating RNA strands from the human virus can get mistakenly enclosed inside the enveloped swine influenza virus. For example, one cell could contain eight swine flu and eight human flu RNA segments. The total number of RNA types in one cell would be 16; four swine and four human flu RNA segments could be incorporated into one particle, making a viable eight RNA segmented flu virus from the 16 available segment types. Various combinations of RNA segments can result in a new subtype of virus (known as antigenic shift) that may have the ability to preferentially infect humans but still show characteristics unique to the swine influenza virus (see Figure 1). It is even possible to include RNA strands from birds, swine, and human influenza viruses into one virus if a cell becomes infected with all three types of influenza (for example, two bird flu, three swine flu, and three human flu RNA segments to produce a viable eight-segment new type of flu viral genome). Formation of a new viral type is considered to be antigenic shift; small changes in an individual RNA segment in flu viruses are termed antigenic drift and result in minor changes in the virus. However, these can accumulate over time to produce enough minor changes that cumulatively change the virus’ antigenic makeup over time (usually years).

Second, pigs can play a unique role as an intermediary host to new flu types because pig respiratory cells can be infected directly with bird, human, and other mammalian flu viruses. Consequently, pig respiratory cells are able to be infected with many types of flu and can function as a “mixing pot” for flu RNA segments (see Figure 1). Bird flu viruses, which usually infect the gastrointestinal cells of many bird species, are shed in bird feces. Pigs can pick these viruses up from the environment and seem to be the major way that bird flu virus RNA segments enter the mammalian flu virus population.

Figure 1. What are the symptoms of swine flu (H1N1)? Symptoms of swine flu are similar to most influenza infections: fever (100F or greater), cough, nasal secretions, fatigue, and headache, with fatigue being reported in most infected individuals. Some patients also get nausea, vomiting, and diarrhea. In Mexico, many of the patients are young adults, which made some investigators speculate that a strong immune response may cause some collateral tissue damage. Some patients develop severe respiratory symptoms and need respiratory support (such as a ventilator to breathe for the patient). Patients can get pneumonia (bacterial secondary infection) if the viral infection persists, and some can develop seizures. Death often occurs from secondary bacterial infection of the lungs; appropriate antibiotics need to be used in these patients. The usual mortality (death) rate for typical influenza A is about 0.1%, while the 1918 “Spanish flu” epidemic had an estimated mortality rate ranging from 2%-20%. Swine flu in Mexico (as of April 2009) has had about 160 deaths and about 2,500 confirmed cases, which would correspond to a mortality rate of about 6%, but these initial data have been revised and the mortality rate currently in Mexico is estimated to be much lower. By June 2009, the virus had reached 74 different countries on every continent except Antarctica, and by September 2009, the virus had been reported in most countries in the world. Fortunately, the mortality rate as of October 2009 has been low but higher than for the conventional flu (average conventional flu mortality rate is about 36,000 per year; projected novel H1N1 flu mortality rate is 90,000 per year in the U.S. as determined by the president’s advisory committee). How is swine flu (H1N1) diagnosed? Swine flu is presumptively diagnosed clinically by the patient’s history of association with people known to have the disease and their symptoms listed above. Usually, a quick test (for example, nasopharyngeal swab sample) is done to see if the patient is infected with influenza A or B virus. Most of the tests can distinguish between A and B types. The test can be negative (no flu infection) or positive for type A and B. If the test is positive for type B, the flu is not likely to be swine flu (H1N1). If it is positive for type A, the person could have a conventional flu strain or swine flu (H1N1). However, the accuracy of these tests has been challenged, and the U.S. Centers for Disease Control and Prevention (CDC) has not completed their comparative studies of these tests. However, a new test developed by the CDC and a commercial company reportedly can detect H1N1 reliably in about one hour; as of October 2009, the test is only available to the military. Swine flu (H1N1) is definitively diagnosed by identifying the particular antigens associated with the virus type. In general, this test is done in a specialized laboratory and is not done by many doctors’ offices or hospital laboratories. However, doctors’ offices are able to send specimens to specialized laboratories if necessary. Because of the large number of novel H1N1 swine flu cases (as of October 2009, the vast majority of flu cases [about 99%] are due to novel H1N1 flu viruses), the CDC recommends only hospitalized patients’ flu virus strains be sent to reference labs to be identified. The CDC developed a PCR diagnostic test to detect novel H1N1 virus. Photo courtesy of the CDC

Source:medicinenet.com

BRAND NAME: Lovaza

DRUG CLASS AND MECHANISM: Lovaza is an antilipemic or fat-regulating drug that is used in addition to diet to reduce triglyceride (TG, a fat-carrying particle in the blood) levels in adult patients with severe elevations in blood levels of TG (≥mg/dL). TG is composed of three fatty acids as well as glycerol, and like cholesterol, comes from either the diet or the liver. High levels of TG in the blood are associated with conditions such as obesity, insulin resistance, poorly controlled diabetes mellitus amongst others that contribute to the risk of atherosclerosis or hardening of the arteries (progressive build up of waxy plaque on the inside of blood vessels) which, in turn, is responsible for coronary artery disease (angina and heart attacks) and strokes.

The precise way in which Lovaza works is not clear; however, its proposed mechanism of action is by decreasing the amount of TG produced by the liver and increasing the removal of TG by the liver. Other drugs that reduce TG levels include fibric acids such as gemfibrozil (Lopid), nicotinic acids such as niacin (Nicobid, Nicolar, Slo-Niacin), and statins such as atorvastatin (Lipitor). Lovaza was FDA approved on November 10, 2004.

PRESCRIPTION: Yes

GENERIC AVAILABLE: No

PREPARATIONS: Capsules: 1 gm

STORAGE: Lovaza should be stored at 25 C (77 F) and not frozen.

PRESCRIBED FOR: Lovaza is indicated as an adjunct to diet to reduce TG levels in adult patients with severe elevations of TG (≥ 500 mg/dL). Off-label uses of Lovaza include prevention of atherosclerosis and prevention of angina, heart attacks, and strokes.

DOSING: The daily dose of Lovaza is 4 grams per day. The daily dose may be taken as a single 4 gram dose (four capsules) or as two, 2 gram doses (two capsules given twice daily). Patients should be advised to swallow Lovaza capsules whole. They should not break open, crush, dissolve, or chew Lovaza capsules.

DRUG INTERACTIONS: Taking Lovaza with an anticoagulant (blood thinner) affecting coagulation such as aspirin, nonsteroidal antiinflammatory drugs (NSAIDS) such as ibuprofen (Motrin), warfarin (Coumadin), and heparin (Hep-Lock U/P) should be monitored periodically as Lovaza may increase the risk of bleeding.

Since some drugs may increase TG levels, patients should tell their doctor or pharmacist of the following medications before using Lovaza since their doctor may want to change the doses of these medications or monitor their effects; beta-blockers such as atenolol (Tenormin), diuretics or water pills such as hydrochlorothiazide (Diuril), and vitamins/supplements (fish/flaxseed/cod liver oils).

Lovaza contains ethyl esters of omega-3 fatty acids which are obtained from the oil of several fish sources. Lovaza should therefore be used with caution in patients with known sensitivity or allergy to fish and/or shellfish.

PREGNANCY: There are no adequate and well-controlled studies in pregnant women. Lovaza should be used during pregnancy only if the potential benefit to the patient justifies the potential risk to the fetus.

NURSING MOTHERS: It is not known whether Lovaza is excreted in human milk and caution should be exercised when administering Lovaza to nursing women.

SIDE EFFECTS: Upset stomach, burping, and strange tastes in may occur. If these effects persist or worsen, patients should notify their doctor. They also should tell their doctors immediately if any of the following rare but serious side effects that suggest increased bleeding occur: easy bleeding from cuts/bruising, black/tarry stools, vomitus that looks like coffee grounds.

Source:medicinenet.com