Educational Review
Malaria from Ticks – Babesiosis
Paul-Erik Uggeldahl
Suvikatu 8 , FIN-80200 Joensuu , Finland . E-mail : pe . uggeldahl @ gmail . com
In Europe the hard tick Ixodes ricinus is the vector of 5 human diseases : tick-borne encephalitis ( TBE ), Lyme borreliosis , tularaemia , anaplasmosis , and babesiosis . The tick can transmit the microbes of these diseases to humans when sucking blood .
The rarest of these diseases is babesiosis , which exists in Finland ( 1 ). Symptoms of babesiosis can be similar to those of granulocytic anaplasmosis . First and foremost , however , it should be noted that babesiosis can mimic malaria . This is unsurprising , since , as in malaria , the vector is a protozoan , an intraerythrocytic parasite .
Babesiosis is a great infector of cattle , although lambs and dogs can also be infected . Vets are often familiar with this disease ( 2 ). However , from contacts in Finland , my experience of their know-how has proved disappointing . This lack of knowledge also applies to ehrlichiosis and borreliosis , and their vectors , the ticks , which globally seems to be the Achilles heel for many .
Skin symptoms are absent in babesiosis . If skin symptoms occur , they may have been caused by the treatment , that is similar to that in malaria . Rashes are also rare in human anaplasmosis ( HGA ), while they dominate in borreliosis . Authors from New England in north-eastern USA ( 3 ) report that babesiosis should be considered in all patients who have an inexplicable feverish disease and have lived in or travelled to an area where the disease is endemic . The disease must also be kept in mind when examining people who have received a blood transfusion within the past 6 months . Transfusion-transmitted babesiosis ( TTB ) is a major problem , which has not been sufficiently investigated in Europe ( 4 ).
History of babesiosis
In 1888 Victor Babes , a Hungarian pathologist and microbiologist , observed intraerythrocytic microorganisms in feverish cattle with bloody urine ( 5 ). Five years later Smith & Kilborne from the USA ( 6 ) observed that ticks were vectors of Babesia bigemina in Texan cattle . Thus , for the first time , it was demonstrated that an arthropod ( tick ) could contract a microbe to a vertebrate host . However , Babes ’ idea of bacteria was not correct ( 5 ).
The first case of human babesiosis was reported half a century later , when a Croatian shepherd , whose spleen had been removed , rapidly succumbed to a disease caused by B . divergens . The first case in a healthy ( immunocompetent ) person was observed in the USA , on Nantucket Island , in 1969 . The disease was caused by B . microti and the tick vector was I . scapularis . New cases appeared on the island and the disease was named Nantucket fever . Human infection with B . microti is almost as common as Lyme disease ( borreliosis ) in some areas of New England ( 3 ).
Prevalence of babesiosis in Europe
Until publication of my Finnish article in 2014 ( 7 ), there was evidence of approximately 50 persons in Europe with clinical symptoms of babesiosis ; most of them caused by B . divergens . A little surprisingly , more than half of these 50 persons are from France and the British Isles ( 4 ). The disease is evidently very rare , but as it is poorly known in Europe many cases may occur without correct diagnosis ( 8 ). Only two cases of human babesiosis have been described in Russia , both caused by B . microti ( 4 ).
The microbe , piroplasm
B . microti is the cause of babesiosis in the USA , whereas in Europe the cause is mainly B . divergens . B . microti does not exist in the larvae of ticks , nor do the respective microorganisms of anaplasmosis and borreliosis . However , B . divergens can be found in this first stage of I . ricinus , and consequently in all 3 stages of sucking blood : larvae , nymphs and adult female ticks ( 4 ).
Another question is which are the reservoir hosts ; vertebrates “ giving ” ticks their blood meal and having living piroplasms in their blood ? To my astonishment I omitted to write about that in my Finnish article ( 7 ). The explanation is that there was no comment regarding these ( reservoirs ) in the many reviews and other articles I read . Thus , work remains to be done !
Frequency of the protozoan in the tick
The reported infection prevalence varies from 0.9 % to 20 %; evidently this has not been sufficiently investigated by medi-
40 Forum for Nord Derm Ven 2017 , Vol . 22 , No . 2