Diagnostic Tools for the Identification of Babesia sp. in Persistently Infected Cattle

Abstract

Bovine babesiosis is a tick-borne disease of cattle caused by the protozoan parasites of the genus Babesia. Babesia bovis, Babesia bigemina and Babesia divergens are considered by International health authorities (OIE) as the principal species of Babesia that cause bovine babesiosis. Animals that recover from a babesial primo infection may remain as persistent carriers with no clinical signs of disease and can be the source of infection for ticks that are able to acquire Babesia parasites from infected cattle and to transmit Babesia parasites to susceptible cattle. Several procedures that have been developed for parasite detection and diagnosis of this infectious carrier state constitute the basis for this review: A brief description of the direct microscopic detection of Babesia-infected erytrocytes; PCR-based diagnostic assays, which are very sensitive particularly in detecting Babesia in carrier cattle; in-vitro culture methods, used to demonstrate presence of carrier infections of Babesia sp.; animal inoculation, particularly for B. divergens isolation are discussed. Alternatively, persistently infected animals can be tested for specific antibabesial antibodies by using indirect serological assays. Serological procedures are not necessarily consistent in identifying persistently infected animals and have the disadvantage of presenting with cross reactions between antibodies to Babesia sp.

Occurrence of Babesia bigemina and Anaplasma marginale in clinically affected cattle in western Santa Catarina, Brazil

“…Unlike infected erythrocytes in peripheral blood where this species is usually found in parasitemia below 1% (ALVAREZ et al, 2019). Another cause of the low occurrence of Babesia spp.…”

“…However, the blood smear and agent observation through microscopic is a fast, practical and inexpensive alternative that veterinarians can use. Although this method is useful only for the detection of infected erythrocytes during the acute phase of the disease and with the high number of parasites present in circulating blood (ALVAREZ et al, 2019), this tool allows the clinician to institute specific treatment for the causative agent of disease, avoiding excessive spending, and excluding other differential diagnoses.…”

Research on Integrated Management for Cattle Fever Ticks and Bovine Babesiosis in the United States and Mexico: Current Status and Opportunities for Binational Coordination

“…Regular PCR and nested PCR techniques have been consistently used to detect infection rates in different herds worldwide and ticks in infesting animals [ 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 ]. In some instances, multiplex methods have been developed to detect not only the bovine babesiosis causative agents, but also the presence of Anaplasma marginale since these pathogens tend to co-exist in the same herds and co-infections have been described [ 62 ].…”

A Review of Human Babesiosis and the Laboratory Diagnosis

“…RAP-1, spherical body protein 2, and spherical body protein 4 of B. bovis have confirmed to be an effective tool for epidemiological investigations in healthy, persistently infected carriers [16] [17]. Nonetheless, the higher false positive is caused due to the sample can be easily polluted during the two-round amplification.…”