Abstract:
Different techniques to diagnose bovine babesiosis were evaluated by
screening 71 cattle presented at the various Veterinary Hospitals of Thrissur and
Ernakulam districts and those maintained at the University Livestock Farm,
Mannuthy and the Cattle Breeding Farm, Thumburmuzhi with symptoms
suggestive of the disease. The techniques employed were examination ofGiemsa
stained blood smears, examination of ticks collected from suspected animals and
serological tests like the Indirect Fluorescent Antibody Test (IF AT) and Slide-
Enzyme Linked Immunosorbent Assay (Slide-ELISA).
Among the 71 cattle, 11 were suffering from an acute illness whereas 60
showed only subclinical symptoms.
Examination of Giemsa stained blood smear could detect Babesia
bigemina organisms in 9 (12.68 per cent) of the total samples, which were mainly
from the acutely infected cattle, except for one, that was obtained from a
subclinically infected calf.
The principal vector of babesiosis was identified as Boophilus annulatus
in the present study. Parasitic masses indicative of the organisms were identified
from the various tick tissues dissected and stained with methyl green pyronine.
Considering the ticks as positive on detection of developmental stages of the
parasite in any of the tissues, ticks from 27 (54 per cent) out of total 50 animals
were interpreted as positive.
The IFAT detected B. bigemina antibodies in 37 (52.11 per cent) and
Slide-ELISA in 39 (54.93 per cent) sera out of 71 samples that were screened.
These two serological techniques were found to be equally efficient, with Slide-
ELISA proving more suitable for use as a field diagnostic test.
Most of the animals that were detected positive for the organisms by all
the tests, were above one year of age. As the number of male and female animals
was too uneven, a sex related comparison could not be appropriately done.
Similarly, a comparison on the performance of the different tests between the
breeds was also not feasible owing to the wide variation between the numbers of
breeds studied.
On evaluation of the different diagnostic techniques, serology and
examination. of ticks were found equally effective in detecting both the clinical
and subclinical forms of the disease over and above the conventional method i.e.,
the blood smear examination. However, examination of Giemsa stained blood
smears continues to be the method of choice to detect acute infections.
