Wednesday, May 28, 2003

Several birds can carry West Nile virus

By Richard Harkness
Knight Ridder Newspapers

Q. Are blue jays and crows the only birds that carry the West Nile virus?

A. More than 110 species of birds are known to have been infected with the virus, so it's best to take note of any dead birds you spot. Most infected birds survive, though many will get sick or die, particularly crows and jays.

Dead birds may mean that the virus is circulating among birds and mosquitoes in that area. That's why it's suggested that you report such sightings to state or local health departments.

Q. My husband was recently prescribed Foltx tablets, which contain 2.5 mg folate, 1 mg vitamin B12, and 25 mg vitamin B6. He also takes a multivitamin that contains 400 mg folate. Is this amount of folate harmful?

A. Folate (folic acid) is a B vitamin. The multivitamin you mention would actually contain 400 mcg of folate, not 400 mg (a thousand times more), a big difference.

Even so, the 2.5 mg plus the 400 mcg (0.4 mg) equals 2.9 mg of folate daily, a fairly large amount.

Foltx is a prescription-only nutritional supplement prescribed to reduce levels of homocysteine, an amino acid normally present in the body. Folate in combination with B6 and B12 holds down homocysteine levels, which, if excessive, can damage the inner artery lining and contribute to the atherosclerotic plaque buildup associated with heart disease.

Though 1 mg of folate daily may be sufficient for most people with high homocysteine, doses up to 5 mg a day have been used, and your husband's dose is well below that.

A danger is that higher doses of folate can mask the signs of pernicious anemia while allowing anemia-related damage to progress. Pernicious anemia is a vitamin B12 deficiency caused by lack of intrinsic factor, a stomach substance required for proper B12 absorption.

However, the Foltx taken by your husband probably provides enough vitamin B12 to overcome any lack of intrinsic factor.