A tick implicated in the spread of equine piroplasmosis in horses and babesiosis in dogs is slowly but steadily spreading within the Netherlands and Belgium, according to researchers.
The research team has reported its findings in respect of Dermacentor reticulatus ticks. Populations of the tick were discovered in the Netherlands in 2004 following several fatal cases of babesiosis in dogs, caused by a protozoan parasite, Babesia canis.
The same tick has been implicated in the emergence in horses of piroplasmosis in the Netherlands, which is considered one of the most important protozoan parasitic diseases affecting horses, mules, and donkeys. In the case of horses, the disease is caused by Babesia caballi and Theileria equi.
The researchers conducted surveillance work, with D. reticulatus ticks collected from 11 locations between 2011 and 2013. They were also collected from different hosts between 2007 and 2013.
A total of 1368 D. reticulatus ticks were collected from four previously known field locations and from five new locations in the Netherlands and from two sites in Belgium (one old and one new location).
A total of 855 ticks collected from eight locations in the Netherlands and two locations in Belgium were tested.
Fourteen ticks – 1.64 percent – collected at four field locations (Dintelse Gorzen, Rozenburg, Slikken van de Heen and St. Philipsland) were positive for B. canis.
Two ticks were positive for B. caballi. One of the ticks was in Dintelse Gorzen in the Netherlands and one was in De Panne in Belgium.
In further work, a further 1092 D. reticulatus ticks were collected between 2007 and 2013 from 40 dogs (132 ticks), two ticks from two humans, 51 ticks from 15 horses, two ticks from two cats, one tick from a roe deer, whereas most ticks (904) were collected from cattle.
None of the ticks collected from these hosts were infected.
“D. reticulatus is continuing its spread into novel areas,” Frans Jongejan and his colleagues reported in an open-access report published in the journal, Parasites & Vectors.
“The finding that some ticks are infected with B. canis and B. caballi poses a threat to the resident dog and horse population and justifies year-round tick control measures,” they said.
“Continued surveillance is required to monitor the distribution of D. reticulatus and associated tick-borne diseases in the resident dog and horse population in the Netherlands and in Belgium.”
The known range of the tick is from southwest England in the west to Central Asia up to the Yenisei river basin in Siberia in the east.
Recent evidence has pointed to the emergence of equine piroplasmosis in the southwest of the Netherlands. Subclinical B. caballi infections and two acute clinical cases of Theileria equi – another protozoan parasite that causes equine piroplasmosis – were diagnosed in resident horses with a sero-prevalence of 1.3 percent among 300 horses in the southwest of the country.
Jongejan was joined in the research by Moniek Ringenier, Michael Putting, Laura Berger, Stefan Burgers, Reinier Kortekaas, Jesse Lenssen and Marleen van Roessel, all from the Utrecht Centre for Tick-borne Diseases, which is part of Utrecht University in the Netherlands; Michiel Wijnveld, from the Medical University of Vienna, in Austria; and Maxime Madder, with the Institute of Tropical Medicine in Belgium and the Department of Veterinary Tropical Diseases at the University of Pretoria in South Africa.
Novel foci of Dermacentor reticulatus ticks infected with Babesia canis and Babesia caballi in the Netherlands and in Belgium
Frans Jongejan, Moniek Ringenier, Michael Putting, Laura Berger, Stefan Burgers, Reinier Kortekaas, Jesse Lenssen, Marleen van Roessel, Michiel Wijnveld and Maxime Madder.
Parasites & Vectors 2015, 8:232 doi:10.1186/s13071-015-0841-2
The full study can be read here.