Degree Final Project defended by Mª Leticia del Barrio Montañés

September 19^th, 2024

The study focused on the detection of Leishmania infantum in ticks collected from wild rabbits (Oryctolagus cuniculus) in the Community of Madrid. Leishmaniasis is a zoonotic disease transmitted by sandflies, and its control is critical due to its global spread and the lack of a vaccine for humans. The primary reservoir is the dog, but the outbreak in Madrid (2009-2012) evidenced hares and rabbits as competent reservoirs, suggesting the need to explore this disease further, for example, by examining other potential common vectors in these wild rabbits, such as ticks.
The main objective was to investigate the presence of L. infantum in rabbit ticks to assess their potential role in the transmission of the parasite. Specific objectives included the identification of tick species, detection of protozoa using real-time PCR, and analysis of the relationship between PCR results and indirect immunofluorescence (IFI), the origin of the animals, and the presence or absence of clinical signs in the rabbits from which the ticks were collected.
Ticks were collected from rabbits in different municipalities, both within and outside outbreak areas. The tick species were identified, and real-time PCR was performed to detect L. infantum. Subsequent statistical analysis was carried out using the WINPEPI program.
A total of 176 ticks were identified, mainly Rhipicephalus pusillus, and to a lesser extent Hyalomma lusitanicum and Haemaphysalis hispanica. L. infantum was detected in 6.51% of the analyzed ticks. No significant correlation was found between Leishmania infection in ticks and the origin of the samples, nor with the clinical signs in rabbits, which could be explained by the asymptomatic nature of rabbits as reservoirs. The prevalence of L. infantum was higher in ticks from areas outside the outbreak.
The tick species found are the most common in rabbits, although Ixodes ventalloi, which is usually found in these animals, was not detected. The prevalence of Leishmania in ticks is lower than that found in those from dogs, the main reservoir. The study had limitations in the number of samples; therefore, it is suggested that more studies be conducted in more geographical locations, as well as further investigation into the role of ticks as vectors to better understand the epidemiology of leishmaniasis