Memorial Day Weekend has
come and gone, and that means one thing – it’s officially summer! And while the
warmer weather comes with exciting outdoor adventures and great vitamin-D
access, it also awakens many creatures – including the biting ones.
In the catalog of
annoying bugs, ticks hold a special place, as they transmit a wide range of
diseases – including bacterial, viral and parasitic ones. Ticks are parasitic
mites of the family Ixodidae and, while there are over 800 known species, only 15 transmit diseases.
Of all tick-transmitted diseases, Lyme (Lyme borreliosis) is the most dreaded.
Currently the most frequently occurring vector-borne disease in the US,
it is transmitted by the blacklegged deer tick (Ixodes scapularis and I.
pacificus).
In the US, around 300,000 people come down with Lyme disease each year –
a far cry from the 30,000–mark reported by the Centers for Disease Control and
Prevention (CDC) before 2015. 96 percent of these cases are reported from 14
states dispersed around the Upper Midwest, Mid-Atlantic and the Northeast,
although infection reports have been country-wide.
Early in their life
cycle, blacklegged deer ticks don’t carry any pathogens. However, they contract
the Lyme bacterium (Borrelia burgdorferi) when feeding on the blood of
an infected host. These infected ticks, which serve as a reproduction site for
the bacteria, then transmit B. burgdorferi via saliva to
humans during a blood meal. Blacklegged deer ticks can transmit Lyme disease
either as nymphs or adults, although the nymphal transmissions are more
prominent.
It was previously
believed that for a successful transmission to occur, ticks needed to be
attached to the skin for 36-48 hours, but according to a recent study published in the
International Journal of General Medicine, Lyme disease can be transmitted in
as little as 16 hours, with the average transmission time of 24
hours.
Lyme disease is
multi-systemic in nature, capable of affecting the skeletal, cardiovascular and
central nervous systems. Known as the great
mimicker, it can present with rheumatoid arthritis, fibromyalgia,
depression, attention deficit hyperactivity disorder, multiple
sclerosis, chronic fatigue syndrome, cardiac manifestations,
encephalitis, and mental illness, to name some of the many associations. Common
ocular symptoms and signs include conjunctivitis, keratitis, uveitis, and
retinitis. The most diagnostic symptom, however, is erythema migrans a.k.a.,
the bulls-eye rash.
Lyme disease has no
“cure”, per se, although some medications, botanicals and/or nutrients may
prove ameliorative. Early detection and treatment is also critical to prevent
multi-system complications that can arise later in life. This is why prevention
is key when it comes to ticks and Lyme disease.
Repel ticks with
essential oils
The CDC
recommends Permethrin, DEET and picaridin as inorganic
solutions to the tick problem, suggesting the treatment of clothes, socks and
boots prior to enjoying outdoor activities. However, research has shown that
certain essential oils (alone or as a mixture) can be just as efficacious in
tick prevention and control.
Essential oils including
rosemary, lemongrass, cedar wood, peppermint, geraniol, citronella and clove
have all been found to possess strong acaricidal properties that make them an
effective organic option in tick control.
In a 2013
study published in the Journal of Medical Entomology, Eco-Exempt IC2
(an organic insecticide with rosemary oil (10%) and peppermint oil (2%) as its
active ingredients) was used to control various stages of I. scapularis in
southern Maine. The black-legged deer ticks were endemic in the test area prior
to the acaricide application, during both nymphal and adult season peaks. In
both cases, the population of I. scapularis in the treated
area was reduced to zero and the effect lasted for 6 months post-application.
In another study examining the efficacy of rosemary essential oil, a larval
mortality of >85% was reported at 10-20% concentrations.
Cedar wood oil has also
been widely reported as a potent acaricide. In a study
published in the Journal of Economic Entomology,
Incense cedar heartwood (Calocedrus decurrens) oil was found to be
highly toxic to nymphal I. scapularis and controlled its
population significantly in the target area. Another study published in Environmental
Entomology reported that red cedar oil resulted in 100% mortality rate in
nymphal I. scapularis at
a dosage of 6.3 mg/ml.
Clove bud and Citronella
oils are also quite effective. One 2017 study reported an 83% repelling
strength for clove bud when used against Dermacentor reticulatus ticks
at 3% concentration. Citronella was reported to have an even higher repellency
of 91% at a concentration of 1.5 percent. Application of the oils may be
topical or sprayed in the environment.
Other helpful tips:
- Avoid
natural tick habitats e.g., leaf litter and thick vegetation.
- Stick
to the middle of trails when you go hiking.
- Take
a quick shower and perform a full body check after spending time in the
wood.
- When
discovered, remove ticks quickly with forceps.
- Treat
dogs and other pets with tick-repelling products.
- Kill
ticks by drying clothes in a high-heat dryer for 10-15 minutes after
potential exposure.
Happy Summer!
