Preliminary Investigation into Plasmodium-like Piroplasms (Babesia/Theileria) among Cattle, Dogs and Humans in A Malaria-Endemic, Resource-Limited Sub-Saharan African City
Date
2022
Journal Title
Journal ISSN
Volume Title
Publisher
Med. Sci.
Abstract
Babesia and Theileria are protozoan parasites belonging to the order piroplasmida, trans mitted by hard ticks, and can cause diseases known as piroplasmosis. Human infections are usually
asymptomatic, except in immuno-compromised persons who present malaria-like symptoms. More over, microscopically, the morphologies of Babesia and Theileria can resemble that of the malaria
parasite, Plasmodium. In malaria-endemic areas with limited resources, these similarities can in crease the possibility of misdiagnosing a patient as having malaria instead of piroplasmosis, which
may further lead to inappropriate choice of disease management. This preliminary investigation
aimed at detecting Babesia/Theileria in cattle, dogs and humans in some parts of Accra. Whole
blood samples were taken from febrile cattle (n = 30) and dogs (n = 33), as well as humans diag nosed with malaria (n = 150). Blood samples of all study subjects were microscopically screened
for possible presence of haemoparasites. Samples whose smears had features suggestive of possible
piroplasmic infection were all given the label “suspected Babesia/Theileria-infected” samples. Nested
polymerase chain reaction (PCR) was performed on extracted deoxyribonucelic acid (DNA) from
all the “suspected” samples of cattle, dogs and humans, with primer sets that can detect 18S rRNA
genes of Babesia/Theileria spp. In addition to this, amplification was performed on the “suspected”
dog samples using the BcW-A/BcW-B primer set which detects the 18S rRNA genes of B. canis, while
the BoF/BoR primer set which targets the rap-1 region of B. bovis and another primer set which
detects the 18S rRNA genes of most bovine Babesia spp. (including B. divergens) were used on the
suspected cattle samples. For the human samples, however, additional amplification was done on the
extracted DNA using primers for the three other Babesia targeted (B. divergens, B. bovis and B. canis).
Microscopy showed possible Babesia/Theileria infection suspected in all three groups of subjects in
the following proportions: cattle (10/30; 33%), dogs (3/33; 9%) and humans (6/150; 4%). DNA from
one-third of the “suspected” dog samples yielded amplification with Babesia canis primers. Moreover,
a broad-detecting set of primers (that can amplify some Babesia and Theileria species) amplified
DNA from nine (9/30; 30%) of the “suspected” cattle samples, but none from those of the humans. Although for this study conducted in the city, the Babesia/Theileria primers used did not amplify DNA
from the six “suspected” human samples; the possibility of Babesia/Theileria infection in humans
in other parts of the country cannot be overruled. There is therefore a need for further studies on
possible emergence of human babesiosis/theileriosis in other parts of Ghana and sequencing for
specific identification of any circulating strain.
Description
Research Article
Keywords
Babesia, babesiosis, P. falciparum