Years of Low Acorn Production Can Boost Lyme Risk

white oak acorns (photo by jhy)

based on a news article in the New York Times

The Northeast is experiencing a year of low acorn production, in contrast to Michigan, where I found the forest floor layered with sweet acorns. But I was not aware that the variations in acorn production can have an influence on the prevalence of Lyme Disease the next year. Here's how it works.

Acorn production normally runs in a series of high and low production years. That's a given. It's what happens when a good year is followed by a lean year that things get interesting for the humans who spend time in the woods. When acorn production is up, the wildlife that depends on the nuts for food flourish, and their populations rise. If a good year is followed by a year of few acorns the large populations of squirrels, mice, and ground-nesting birds will crash, as they will have a hard time finding enough food.

Of course, when the wildlife increases, so do the tick populations. And when the wildlife dies off, all those ticks will be looking for fresh blood. Humans in the woods make them very happy.

So, if you live in the Northeast, be sure to take your DEET to the woods next spring!

Death in Minnesota from Tick-Borne Virus

deer tick life stages and metric rule. The adult ticks (left) are approximately 1/8 of an inch long, while the nymph (third from left) is just under 1/16 of an inch. (from Minn Dept of Health)

from the Minnesota Department of Health and Minnesota Public Radio

A Minnesota woman has died from a tick-borne virus known as the Powassan Virus, named for a city in Ontario where is was first described in 1958. Only 60 cases have been reported in the past five decades, until recently. In the past three years, six cases have turned up in northern Minnesota. The victim was in her 60s, and died from the resulting brain infection after being bitten.

The virus is carried by the deer tick, and possibly Ixodes cookei, sometimes known as the groundhog tick. The virus causes an inflammation of the brain or the brain's membranes, resulting in encephalitis, or meningitis. Although rare, the disease is extremely serious, with approximately 10% fatality. In addition, the virus is transmitted from tick to human much more quickly than the Lyme Disease virus, which can take 12-48 hours. Times as short as 15 minutes have been posted on some web sites, but the MN health department states the the time is shorter, but not known with certainty.

Minnesota NCT hikers should use precautions. Counties included in the warning for this disease include Cass, Itasca, and Hubbard, through which the trail passes. Symptoms include fever, headache, vomiting, weakness, confusion, loss of coordination, speech difficulties, and memory loss. It can take a week after being bitten for symptoms to appear.



This segment is on NCTA map MN-09 and MN-10

See Laurentian Lakes Chapter of the NCTA
See Itasca-Moraine Chapter of the NCTA

General Resources for Hike Planning

by JHY

In a continuing effort to help those who are planning hikes on the NCT another page of information has been retrieved from the old NCT web site.

This page is simply a collection of links to some resources:

• 15-day weather forecasts for cities along the trail
• National Weather Service regional map with current weather conditions and hazards.
• National Weather Service 3-Month Temperature Outlook
• Precipitation Outlook from the National Centers for Environmental Prediction
• Snow Cover from Weather Underground
• National Weather Service 5-day flood advisories
• National Weather Service fire information
• USGS Water Watch
• CDC Lyme Risk Map
• ALDF Lyme Incidence Maps
• CDC West Nile Reported Cases Map
• UV Index Map

Go to the unofficial home page of the North Country Trail Long Distance Hikers and click on the link in the right column

Vaccine for West Nile on the Horizon?

from a news release of the University of Queensland

Research conducted at The University of Queensland could contribute to the development of a vaccine and cure for West Nile virus and Dengue fever.

Led by Associate Professor Alexander Khromykh, a team of researchers from UQ's School of Molecular and Microbial Sciences identified a novel characteristic of the virus family to which these diseases belong.

This family, the flaviviruses, produces a small molecule. One of its functions is to control the response of the host to the viral infection. The molecule itself is part of the genetic material of the virus, and is labeled sfRNA.

The researchers stated that all flaviviruses tested thus far have contained the sfRNA. This means that targeting that specific part with an antiviral therapy may be effective for the whole range of flaviviruses.

By using reverse genetic engineering they were able to generate viruses that do not produce this sfRNA. The viruses that were missing the sfRNA were no longer able to kill their hosts or elicit disease symptoms. However, the engineered viruses did trigger the antiviral immune response in the host. This means that the body would create its own protection against all flaviviruses without contracting the disease.

These tests were conducted with mice. "The knowledge obtained from our studies with West Nile virus should be readily applicable for designing anti-viral drugs and engineering similar vaccine candidates for other medically important flaviviruses," said team leader Associate Professor Alexander Khromykh.

The study will be published in the December issue of the prestigious journal from Cell Press, Cell Host & Microbe.

"Treat" a Bug with Toxic Blood

a news release of American Society of Tropical Medicine and Hygiene

Most successful vaccines and drugs rely on protecting humans or animals by blocking certain bacteria from growing in their systems. But a new theory actually hopes to take stopping infectious diseases such as West Nile virus and Malaria to the next level by disabling insects from transmitting these viruses.

Researchers say that vaccines and drugs may be used to prematurely kill ticks, sand flies and mosquitoes, known as disease vectors. These are the insects responsible for most deaths world wide.

The idea is to make blood meals from humans lethal to mosquitoes so they die before they can transmit a disease. Called endectocides, these vaccines are administered to humans. When the pest feeds on the blood it dies. Endectocides are currently mass administered to human populations to control the worm parasites that cause river blindness and are widely used in animals for worm control.

A vaccine is in early development for cattle, whose production is greatly affected by tick-borne diseases. The University of Oklahoma is working on a vaccine to target tick-protective genes, so when ticks feed on immunized cattle, the vaccine antibodies interfere directly with the biology of the tick and its feeding pattern which results in reduced tick populations. The vaccine model being developed for cattle, which is called a dual target vaccine approach because both ticks and tick-borne pathogens are targeted, will likely be applicable to other ticks and the bacteria that they transmit.

Advantages are that these control measures are more targeted than environmental spraying of insecticides; proper application would kill older frequently-biting insects and interrupt disease transmission; resistance would be slower to develop; and there may be little cross-resistance from agricultural applications.