Culture, isolation and propagation of Babesia caballi from naturally infected horses.

The research is focused on successfully isolating and cultivating Babesia caballi from horses in South Africa, discovered by conducting in vitro cultures on blood samples from horses which show no apparent symptoms of being infected.

Research Context and Methodology

• Babesia caballi is a type of parasite known to infect horses. It is carried by ticks and causes babesiosis or ‘Piroplasmosis’, a serious, sometimes fatal disease of horses. This research study aimed at identifying horses that are carriers of B. caballi without showing any health symptoms or detectable parasitaemia (presence of parasites in the blood), as these carrier animals play a crucial role in the epidemiology of the disease.
• Thirteen blood samples were gathered from horses in South Africa. Five of these samples were known to be seropositive towards B. caballi (presence of specific antibodies in the blood against the organism), and eight were seropositive for both B. caballi and another parasite, Theileria equi.
• These samples were subjected to in vitro culture – a process wherein organisms are grown outside their natural environment, in a controlled setting. This helped researchers identify any carrier animals in the sample population.
• The cultures were started using a medium enriched with L-cysteine, an amino acid, under two different atmospheres: an oxygen-reduced gas mixture or a 5% CO2-in-air atmosphere.

Findings

• Among the five animals with B. caballi seropositivity, all were identified as carriers when the cultures were initiated under an oxygen-reduced atmosphere. When the cultures were initiated under normal atmospheric conditions, only four became culture positive.
• Within the eight samples that were seropositive for both B. caballi and T. equi, two were found to be carriers of both parasites. The remaining six samples were found to be carrying only T. equi.
• The experiment highlighted the significance of atmospheric conditions in the successful culture of B. caballi.

Implications

• The findings of this study on the culture, isolation, and propagation of B. caballi may have applications in diagnosing and controlling the spread of equine babesiosis in areas where the disease is prevalent.
• Identifying and understanding carriers of B. caballi (that do not show any symptoms) is crucial in managing and combating Babesia infection at an epidemiological level.
• The study further underscores the importance of environmental conditions (such as atmosphere) during in vitro culture of parasites for efficient results.