There are several species of ticks in the Netherlands that bite horses. When ticks bite horses, they can transmit a number of pathogens, including Borrelia burgdorferi, Theileria equi, Babesia caballi and Anaplasma phagocytophilum.
Ticks, a source of pathogens
Research found that tick-related infections are more common than previously suspected and it is therefore vital that these infections are studied and monitored in greater detail.
In her dissertation, Doctoral Candidate Catherine Butler examined the prevalence and importance of tick-related infections in horses in the Netherlands, as well as the diagnosis and treatment of these infections. Butler’s conclusion is that tick-related infections are more common than previously suspected and it is therefore vital that these infections are studied and monitored in greater detail.
The most important results of Butler’s research are that the conditions previously considered ‘exotic’, such as equine piroplasmosis, are becoming increasingly common in the Netherlands. In the case of piroplasmosis, this is due in part to the fact that the tick that carries the disease, Dermacentor reticulatus, only recently appeared in the country.
Her research has also shown that of the 45% of the 47 horses observed for a period of 9-23 months after a tick bite experienced a Borrelia infection and 23% experienced an Anaplasma infection. Although the chance of infection after a bite is significant, these infections seem to progress without serious clinical symptoms in horses kept for recreational purposes.
In order to determine which tick species can be found on healthy horses in the Netherlands, veterinarians were asked to send Butler the ticks they found during their examinations. The result is that Ixodes ricinus is the most common tick species affecting horses.
The unexpectedly large number of Ixodes-nymphs (young ticks) sent indicates that relatively large numbers of ticks live in certain areas in the Netherlands. Since these ticks can also bite humans and transfer their pathogens to them, the people recreating in those areas run the risk of infection with tick-transmitted agents.