Page 32 - Oct-Dec 2024 Edition

| HEALTH FEATURE

By Dick Stockley

TICK FEVER

’ve been asked to write an article on tick fever. over 80% of the ticks were infected. The only
Should be easy, right? A common disease that conclusion is that in endemic communities where
Iis pretty straight forward. A lot of people are the ticks are common everyone gets infected. It’s
diagnosed as tick fever, some vets diagnose it not diagnosed, it gets better on its own and they
in dogs routinely. By coincidence our last visit to are then immune for life. Similarly, Borelia Duttoni:
a vet and a doctor in Botswana both suggested it’s commonly found in returning visitors and
tick fever. Only one problem: there is no such tourists but across Africa it’s rarely diagnosed in
disease. the community. Ticks are not discriminatory, they’ll
bite anyone, so again it must be common, just
In Europe “Tick fever” usually means Lyme not diagnosed. And that’s why they are important.
disease: a tick-borne disease caused by a We certainly diagnosed African relapsing fever
spirochete borrelia burgdorferi. We don’t have it often enough in our patients from the history and
in Africa. We have a milder tick-borne disease in simple blood tests. Studies using pcr show that
the same family, Borelia Duttoni, rather alarmingly the spirochete itself is only found on microscopy
named after Jonathan Dutton whodiscovered and in a tiny percentage of cases with positive pcr. So,
subsequently died from it about 120 years ago. centers that have pcr will find cases: everyone
Its common name is African tick borne relapsing else will miss it. I’ve not heard of anyone doing
fever, and in general it’s a lot less severe than pcr for Borelia so it’s either diagnosed by clinical
Lyme disease. However there are other Borelia suspicion or missed. It classically causes a
species in Africa which are more severe, one sudden high fever with all the other associated
species that is spread by both ticks and lice are non-specific symptoms of joint pains, backache
Borelia recurrentis, which has high mortality. and headaches. It lasts a few days, then
Good news: it’s rare, only common in South antibodies kick in, and they get better. Then the
Sudan. The other group of diseases commonly bacteria change its antigens and off it goes again
called tick fever are Rickettsia. There’s about 10 with another sudden fever a week or 2 later. And it
different Rickettsia, some have quite well-known can carry on for 5 to 10 cycles: 5 or more days of
common names such as Rocky Mountain fever, then better, and relapsing after a week or 2.
spotted fever, tick typhus, murine typhus, scrub Which is why it’s called relapsing fever. Not to be
typhus, which is my favourite real name: Orientia confused with “undulant fever” which has a similar
tsutsugamushi. Sounds like a restaurant serving recurring pattern but is due to brucellosis. The
rice wrapped up in seaweed. reason why most people get better without getting
African tick bite fever is due to Rickettsia the whole 3 months of relapsing fever is because
Africae: R. Africae is reported as “no deaths many antibiotics will treat it. So, the first time
ever recorded.” However, there are other someone gets a fever they are told its malaria.
rickettsia diseases in Africa. R. Conorii causes Old docs like me will remember that before rapid
Mediterranean spotted fever also called “Kenya tests made the diagnosis of malaria certain, every
tick typhus” which can be nasty and fatal. Louse fever was diagnosed as malaria. I read a German
borne typhus is often fatal but again good news: study about 25 years ago which found that the
the most severe of the typhus Rickettsial diseases diagnosis of malaria was wrong in 95% of cases.
are no longer seen in Uganda. When they looked carefully they found around 20
So why are they important, are they common, and different diseases as the actual cause of fever in
are they easily treated? First are they common. A these patients, including the different tick fevers.
research study done in 2013 in Uganda collected I also remember CDC identifying yellow fever
and tested the tick vector of R. Africae and found in that sudden epidemic a few years ago. Their

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