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Q: Lyme disease ( Answered 5 out of 5 stars,   1 Comment )
Subject: Lyme disease
Category: Health > Conditions and Diseases
Asked by: guilla-ga
List Price: $10.00
Posted: 10 Apr 2002 14:18 PDT
Expires: 17 Apr 2002 14:18 PDT
Question ID: 118
I'd like to know more about Lymes Disease - specifically information pertinent
to one who spends a lot of time in the outdoors in Northern California.
Subject: Re: Lyme disease
Answered By: drdavid-ga on 10 Apr 2002 14:56 PDT
Rated:5 out of 5 stars
As yet, Lyme disease has not been widely reported in California. There were 139 
reported cases in 1999 and 104 in 2000 (extensive statistical data and links to 
more can be found at 
However, there is some concern that incidents have been underreported, and the 
number of cases may, in fact, be much higher. That said, Northern California is 
one of the places in the USA where you are definitely at risk for exposure to 
Lyme disease and other tick-borne diseases.

A good general description of the disease, how to avoid exposure, how to 
recognize it and what sort of treatment is available is summarized in the 
following text drawn from

"Lyme Disease
Lyme disease is a rapidly emerging bacterial infection that is spread to people 
by the bite of infected ticks. 
Lyme disease can cause a rash, flu-like symptoms, and aching joints. 
Lyme disease can be treated with antibiotics. Without treatment, Lyme disease 
can cause serious, long-term health problems. 
To prevent Lyme disease: 1) protect yourself from tick bites, 2) remove 
attached ticks promptly, and 3) get early diagnosis and treatment. 

What is Lyme disease?

Lyme disease is an infection transmitted by the bite of certain, very small, 
infected ticks. Lyme disease gets its name from the town of Lyme, Connecticut, 
where the illness was first identified in the United States in 1975.


What is the infectious agent that causes Lyme disease?

Lyme disease is caused by a corkscrew-shaped bacterium, or spirochete, called 
Borrelia burgdorferi. Ticks infected with the bacterium spread the disease to 


Where is Lyme disease found?

Cases of Lyme disease have been reported by nearly every state in the United 
States, but the disease is concentrated in the east coastal states, the north 
central states, and northern California. Connecticut, Rhode Island, New York, 
New Jersey, Delaware, Pennsylvania, Maryland, and Wisconsin account for about 
90% of all cases.

In the Northeast and Great Lakes region, Lyme disease is spread by the black-
legged tick, which lives in wooded areas, grasslands, and yards. In the Pacific 
Northwest, the disease is spread by the western black-legged tick. In the 
Southeast, the disease is thought to be spread by the black-legged tick.


How do people get Lyme disease?

Ticks become infected with the Lyme disease bacterium by feeding on infected 
animals, such as mice, chipmunks, and other wild rodents. Lyme disease is 
passed to humans and other animals when a tick infected with the bacterium 
bites the person or animal and stays attached long enough (usually more than 36 
hours) to take a blood meal.

The tick that spreads Lyme disease has a 2-year life cycle, and feeds once in 
each of its three life stages -- larvae, nymph, and adult. In the tick's larvae 
stage, it is tan, the size of a pinhead, and feeds on small animals like mice. 
During the nymph stage, the tick is the size of a poppy seed, beige or 
partially transparent, and feeds on larger animals such as cats, dogs, and 
humans. Adult ticks are black and/or reddish and feed on large mammals such as 
deer, dogs, and humans.


What are the signs and symptoms of Lyme disease?

The early stage of Lyme disease is usually marked by one or more of these signs 
and symptoms:

Chills and fever 
Muscle and/or joint pain 
Swollen lymph glands 
A characteristic skin rash, called erythema migrans 
The skin rash is a red circular patch about 2 inches in diameter that appears 
and expands around the site of the tick bite. The center may clear as it 
enlarges, resulting in a "bulls-eye" appearance. The rash may be warm, but it 
usually is not painful or itchy.

Some infected people do not recognize the early symptoms and are diagnosed only 
after complications occur.


What complications can result from Lyme disease?

Persons who did not have or did not recognize the early symptoms and who did 
not receive treatment can end up with serious complications:

Arthritis (swelling and pain) in the large joints, which can recur over many 
Nervous system problems, such as numbness, meningitis (fever, stiff neck, and 
severe headache), and Bell's palsy (paralysis of the facial muscles, usually on 
one side) 
Irregularities of the heart rhythm 

How soon after exposure do symptoms appear?

Early symptoms can develop within a week to a few weeks of the tick bite. Other 
symptoms can appear weeks, months, or years later.


How is Lyme disease diagnosed?

Lyme disease is diagnosed by a physical examination and medical history. The 
clinical diagnosis is supported by laboratory testing.

Diagnosis of Lyme disease can be difficult. Current tests are not completely 
accurate, and the symptoms can mimic those of other diseases. Diagnosis is 
easiest when there is a skin rash.


Who is at risk for Lyme disease?

Lyme disease can affect anyone. Persons who spend time in brushy and wooded 
areas are at increased risk of exposure. The chances of being bitten by a tick 
are greatest during times of the year when ticks are most active. Deer ticks in 
the nymph stage are active from mid-May to mid-August. Adult ticks are most 
active in mid- to late fall and early spring.


What is the treatment for Lyme disease?

Lyme disease is treatable with antibiotics taken for 3 to 4 weeks. More 
difficult cases may require longer treatment and combinations of drugs. Re-
infection from tick bites is possible after treatment.


How common is Lyme disease?

Lyme disease is the most common disease spread by ticks in the United States. 
More than 16,000 cases were reported by 45 states in 1996. However, because of 
considerable under-reporting and misdiagnosis, the actual number of cases is 
probably several times higher.


Is Lyme disease an emerging infectious disease?

Yes. Lyme disease is a rapidly emerging infectious disease. Since it was first 
recognized in the United States in 1975, reports of Lyme disease have increased 
substantially, and the disease is now found in several regions of the country. 
Factors contributing to the rise in Lyme disease in humans is a thriving tick 
population and the expansion of suburbs into formerly wooded areas, which 
increases people's exposure to infected ticks.


How can Lyme disease be prevented?

A Lyme disease vaccine is under development but is not yet available. The only 
sure way to prevent the disease is to avoid exposure to infected ticks. 
Especially avoid areas where wild mice might live, such as the edges of yards, 
fields, and woods with low, dense groundcover.

If this is not possible, you can reduce your risk by taking these precautions:

During outside activities, wear long sleeves and long pants tucked into socks. 
Wear a hat, and tie hair back. 
Use insecticides to repel or kill ticks. Repellents containing the compound 
DEET can be used on exposed skin except for the face, but they do not kill 
ticks and are not 100% effective in discouraging ticks from biting. Products 
containing permethrin kill ticks, but they cannot be used on the skin -- only 
on clothing. When using any of these chemicals, follow label directions 
carefully. Be especially cautious when using them on children. 
After outdoor activities, check yourself for ticks, and have a "buddy" check 
you, too. Check body areas where ticks are commonly found: behind the knees, 
between the fingers and toes, under the arms, in and behind the ears, and on 
the neck, hairline, and top of the head. Check places where clothing presses on 
the skin. 
Remove attached ticks promptly. Removing a tick before it has been attached for 
more than 24 hours greatly reduces the risk of infection. Use tweezers, and 
grab as closely to the skin as possible. Do not try to remove ticks by 
squeezing them, coating them with petroleum jelly, or burning them with a 
Large brown ticks that are commonly found on dogs and cattle do not carry the 
Lyme disease bacterium. If you remove a very small tick and want to have it 
tested for Lyme disease, place it in a clean pill vial or tight-sealed plastic 
storage bag with a moistened cotton swab. Contact your health-care provider and 
local health department. 

This fact sheet is for information only and is not meant to be used for self-
diagnosis or as a substitute for consultation with a health-care provider. If 
you have any questions about the disease described above, consult a health-care 
guilla-ga rated this answer:5 out of 5 stars
That was very informative!

Subject: Re: Lyme disease
From: mydogrex-ga on 10 Jul 2002 09:25 PDT
Relevant abstract: 

1: Am J Trop Med Hyg  2000 Mar;62(3):415-22 
Density and spatial distribution of Ixodes pacificus (Acari: Ixodidae) in two
recreational areas in north coastal California.
Li X, Peavey CA, Lane RS.

Department of Environmental Science Policy and Management, University of
California, Berkeley 94720-3112, USA.

The density and distribution of Ixodes pacificus was assessed at 2 parks in
north coastal California. The density of I. pacificus adults and nymphs varied
significantly between years, trails, and sides of trails. Adult ticks occurred
on vegetation along sun-exposed trails in January through March, their density
(0-1.93 per 20 m) correlated with brush density, trail width, and presence of an
uphill slope. Nymphs (0.06-5.10 per 20 m) occurred in leaf litter along shaded
trails in May-July. Adult I. pacificus were rare at picnic sites (0.00-0.24 per
20 m), but nymphal densities (0.93-2.37 per 20 m) were comparable with those
along some shaded trails. The prevalence of Borrelia burgdorferi in ticks (2.8%
overall) did not differ significantly between locations, years, or stages. We
conclude that the risk of acquiring Lyme disease in these sites is low, but
varies among trails, seasons, and years.

: Slowik TJ, et al. Birds and their ticks in nort...[PMID:11534638] 

2: Chang CC, et al. Molecular evidence of Bartone...[PMID:11283031] 

3: Wright SA, et al. Ecology of Borrelia burgdorfe...[PMID:11126549] 

4: Li X, et al. Density and spatial distribut...[PMID:11037789] 

5: Olson PE, et al. Canines as sentinels for Lyme...[PMID:10730940] 

6: Peavy CA, et al. Role of small mammals in the ...[PMID:9291589] 

7: Fritz CL, et al. Seroepidemiology of emerging ...[PMID:9180183] 

8: Lane RS. Risk of human exposure to vec...[PMID:8780455] 

9: Brown RN, et al. Natural and experimental Borr...[PMID:7933283] 

10: Ley C, et al. Lyme disease in northwestern ...[PMID:8053175] 

11: Schwan TG, et al. Distribution and molecular an...[PMID:8308101] 

12: Schoeler GB, et al. Efficiency of transovarial tr...[PMID:8433348] 

13: Brown RN, et al. Lyme disease in California: a...[PMID:1604318] 

14: Lane RS, et al. Lyme disease in California: i...[PMID:1941942] 

Type the PMID here to view the abstract:

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