by: Eric Norberg, The lagoon at Oaks Bottom, shown in this photo from the south end looking northeast in the spring, used to be a prolific source of mosquitoes two decades ago--but recent Multnomah County strategies to manage water levels to prevent mosquito breeding, combined with occasional application of the organic substance B-T, has greatly reduced this  key vector of West Nile virus infection.

It was on the front page of the June, 2004, issue of THE BEE that we reported local officials expected the imminent arrival of the West Nile virus into the Portland metropolitan area; the virus had been spreading steadily across the United States since 1999, when it arrived on the east coast from Africa, and seemed poised to reach the City of Roses at any time.

But nothing happened. No cases were reported locally in the rest of 2004, in all of 2005, and until the second week of September of this year. But now the virus is here. The virus is fatal to some types of birds, and a dead jay and a dead crow found in Inner Southeast Portland were announced on September 11th by Multnomah County health officials to have died of the viral infection.

One of the two birds was found in the Brooklyn neighborhood; the other to the north, in the Buckman neighborhood.

The virus is no cause for panic. The disease cannot pass between people; its vector of infection is through mosquito bites, in circumstances in which a mosquito has bitten an infected bird, and then gone on to bite a person. Even so, most of the time, the infection either goes unnoticed, or is experienced as a mild case of flu.

However, as with flu, individuals with compromised immune systems, and the elderly, can experience life-endangering symptoms in rare cases, so precautions are adviseable.

These precautions include ventilating houses through screened doors and windows, especially during the dawn and dusk hours when mosquitoes are most active, and wearing mosquito repellent when circumstances dictate spending time outdoors in the summertime. Mosquitoes remain a concern until the first frost of the autumn season.

Meantime, Multnomah County has been fine-tuning its mosquito control strategies; two decades ago, mosquitoes breeding in Oaks Bottom were a major summertime annoyance in Sellwood, Westmoreland, Eastmoreland, Reed, and Brooklyn; in recent years sophisticated management of water levels in the Oaks Bottom lagoon, combined with application of the eco-friendly control agent B-T, have almost eliminated mosquitoes in the surrounding neighborhoods.

Since 2004, 59 residents of other parts of Oregon have been diagnosed with West Nile virus infections, all but 14 of them just this year. But none has died.

Residents are asked to report any dead birds, as well as any noticed mosquito problem, to Multnomah County at 503/988-6453.