The transovarial transmission of Babesia caballi by Hyalomma truncatum.

The research paper discusses how the Babesia caballi parasite, found in a horse from South West Africa/Namibia, is transmitted from an adult female tick to its offspring. Despite being in very low quantities, the parasite had a significant impact on 45% of the ticks that fed on the infected horse. Furthermore, 70% of those infected ticks died or only laid a few eggs.

Parasite Transmission in Ticks

• The research was on the transovarial transmission of Babesia caballi by the tick species Hyalomma truncatum. This means the study looked at how the parasite could be passed down from an adult female tick to its offspring. It was established that this transmission is possible even when there are very low concentrations of the parasite.
• The research team found that 45% of the ticks that fed on the infected horse became infected with the parasite. This implies a high level of infectivity that B. caballi has for adult H. truncatum.

Impact on Infected Ticks

• Despite the low level of parasitaemia (presence of parasites in the blood), the ticks suffered severe effects from the parasite. Almost 70% of the infected ticks died either during oviposition (the process of laying eggs) or after producing only a few eggs. This indicates a detrimental impact of the parasite on the tick’s life and reproductive capabilities.

Manifestation of Infection in Horses

• The study also revealed the impact of the infection on the horses. The prepatent period (time from infection to when the parasite can be detected) was approximately 10 days. Surprisingly, despite the very low parasitaemia, the infection had low pathogenicity. In simple terms, the infection was not very harmful to the horses.
• Also, the infected animals experienced a spontaneous recovery, suggesting they were able to naturally overcome the infection.

Conclusion

• This study showed the strong influence of Babesia caballi on both its tick host and the host animal. Despite low parasitaemia, it significantly affects ticks, impacting mortality and reproduction. In contrast, the effect on horses is not overly harmful, with animals showing the ability to naturally overcome the infection. This research can provide further insights in the control and prevention of diseases transmitted by ticks.