Natural Perspectives

Vic Leipzig and Lou Murray

Before the days of electronic sensors coal miners brought caged

canaries down into the mines to warn them of declining air quality. We

have our own “canaries” right here in Huntington Beach, wild birds that

can warn us of deadly diseases.

We talked with James Webb, PhD., Technical Director of Orange County

Vector Control District. His team traps house finches and house sparrows

in Central Park and other locations throughout Orange County every two

weeks. They take blood samples, looking for viruses that spread via

mosquitoes. One of the things they’re looking for is West Nile virus,

which causes West Nile fever, a form of encephalitis or inflammation of

the brain and spinal cord. West Nile fever kills people, horses and

birds, and it’s headed our way.

West Nile fever was first discovered in 1937 in the West Nile region

of Uganda. The disease is now found widely in Africa, eastern Europe, the

Middle East and western Asia. It arrived in the western hemisphere in

1999, showing up first in New York.

According to Webb, scientists thought that the New York epidemic would

be a limited outbreak followed by a die-off of the virus during winter.

No such luck. The virus survives cold winters mainly in infected birds.

In the spring, mosquitoes bite these birds and spread the disease

further. In just three years, West Nile virus has multiplied among birds

in 27 states from Maine to Florida. It’s now west of the Mississippi.

As of last month, 10 human deaths have occurred in the U.S. from West

Nile fever. This disease has claimed more than twice as many lives as

anthrax, yet we hear little about it.

Local horse owners should take note. In addition to killing 10 people

and countless wild birds, West Nile virus has infected 345 horses in 19

states. Over half of those horses died or were euthanized.

No one is sure how this virus hopped across the Atlantic, but it may

have arrived via an infected bird smuggled into the country. The strain

of West Nile virus found in the U.S. is closely related to the strain

found in the Middle East. When the virus first showed up in New York,

there was speculation that it was an act of terrorism, but there was no

proof. In light of the recent anthrax attacks and the propensity of Al

Qaida terrorists to target New York, this remains an interesting

speculation.

The virus has been found in over 70 species of birds, but crows appear

to be unusually sensitive with a high mortality rate. The virus also can

cause disease in dogs, cats and several other small mammals. West Nile

virus cannot be transmitted directly from birds or animals to people, or

from person to person. Instead, it spreads through the bite of an

infected mosquito.

In warmer southern climates where mosquitoes thrive, the virus is

spreading rapidly. West Nile fever may soon be in California, brought

here by infected migratory birds. When it arrives, we’ll know about it.

Long before West Nile virus became a concern, Orange County Vector

Control was monitoring for two other viruses, St. Louis equine

encephalitis (SLE) and Western equine encephalomyelitis. These viruses,

which are closely related to West Nile virus, cause encephalitis in both

horses and humans and also are spread through mosquito bites. Webb noted

that there was an epidemic of St. Louis encephalitis in the Los Angeles

basin in 1984.

“Because we were set up to monitor SLE, we’re in good shape to

intercept West Nile if it comes to our part of the world,” Webb said.

He believes that the virus could arrive in Orange County as early as

next spring.

How worried should we be? Well, even during an outbreak of West Nile

fever, the chances of being infected are very small. In a region where

the virus is found, only about 1% of the mosquitoes carry the virus in

their salivary glands. Of all the people bitten by an infected mosquito,

few even develop the flu-like symptoms of West Nile fever, and less than

1% develop a serious infection. But of those who do become seriously ill,

about one out of 10 die.

Symptoms of West Nile fever include fever, headache and body aches,

sometimes accompanied by a skin rash and swollen lymph glands. Elderly

people are at much higher risk for developing a serious infection, which

is characterized by muscle weakness, headache, high fever, stiff neck and

symptoms that can include disorientation, tremors, convulsions, paralysis

and coma. These symptoms may begin three to 15 days after a bite by an

infected mosquito.

Bacterial infections like anthrax can be treated with antibiotics.

Unfortunately, there is no specific treatment for viral infections such

as West Nile fever. A vaccine for horses was approved on an emergency

basis in August. Hopefully, a human vaccine will be available before the

“canaries” stop singing.

* VIC LEIPZIG and LOU MURRAY are Huntington Beach residents and

environmentalists. They can be reached at o7 [email protected] .