4-5% of Overseas hunters get this disease - and if
your doctor does not identify Tick Bite Fever, you may be a few days
away from multi-organ failure and death.
Although this is an extreme situation, it is wise to
Tick bite fever is an infection caused by bacteria
which are transmitted by infected ticks to humans in their saliva
when they bite. The bacteria can also infect through small skin
abrasions when the tick is crushed on your skin. Bacteria are passed
from the infected tick to her eggs, thus propogating the infection
in her offspring. The Rickettsial bacteria are not able to survive
outside of living cells.
Tick bites most often occur when hunting or hiking
in the bushveld, particularly where there is long grass.
Hardticks, which have life cycles that involve dogs,
rodents or other animals are the hosts of the bacteria. Amblyomma
ticks will actively seek out humans on which to feed, while
Rhipicephalus ticks tend to lie in wait on grass and grab you
with their tiny claws when you brush past.
In South Africa, the cause of tick bite fever is
either R. conorii (as in the table), or R. africae.
Typical features include the presence of a black
mark at the site of the bite, The blackened bite mark is called an
eschar. It looks like a small ulcer (2-5mm in diameter) with a black
center, similar to a spider bite. The bite site may be difficult to
find with the eschar appearing once the other symptoms begin.
A rash is not always present but when it does occur,
it consists of small red marks on the skin, raised slightly above
the skins surface. It will typically start on the arms and legs,
spreading to the abdomen and if severe, even to the palms and soles.
African tick bite fever is usually mild and serious
complications and death are rare. Rocky Mountain Spotted Fever is
more severe with a death rate of up to 25% if left untreated.
© David Scharf / Science Faction / Corbis
If shortly after your safari you have a severe
headache, fever, swollen lymph nodes and feel really ill a week or
so, suspect tick bite fever, especially if the area is a known tick
bite fever area.
The presence of the bite mark or rash is a strong
diagnostic sign. Blood tests will confirm the presence of antibodies
produced by your immune response cells in reaction to the infection.
But, the antibodies may only show up after a few weeks.
most cases you will get better in about two weeks without treatment.
Treatment with the antibiotic doxycycline can shorten the duration
of symptoms and reduce the chance of developing a serious
complication. Chloramphenicol may be used. There is no vaccine
against tick bite fever.
The incubation period (time from the infected bite
to the appearance of symptoms) is 5-7 days.
Some forms of tick bite fever are fairly mild and
self-limiting people may get better on their own without specific
treatment. This can take about two weeks. Treatment with an
antibiotic can shorten the duration of symptoms and reduce the
chance of a serious side-effect.
severe cases, antibiotic therapy is more important, and can be life
saving. The antibiotic doxycycline is the preferred agent for
treating tick bite fever. Some people are not able to take
doxcycline, in which case chloramphenicol, or sometimes
ciprofloxacin, may be used instead.
There is no vaccine against tick bite fever, and
taking prophylactic antibiotics (as one does for malaria) has never
been shown to be effective or necessary.
Mitchell is a bow hunter, outdoorsman and the author of
several books on African wildlife and survival
As with most things, prevention is better than cure
- and early diagnosis speeds recovery.
Wear long sleeved shirts,
long pants and shoes. Apply an insect repellent to exposed skin.EARLY DIAGNOSIS If youve been in a known tick bite
fever area and are suffering from a fever, headache, swollen
lymph nodes and have located the eschar (bite mark), seek
The eschar is not always visible so dont rely on its presence
as a diagnostic sign.