Hemogregarine parasites are found in many vertebrates, being most prevalent in reptiles, with lizards being the second most common hosts after snakes. Hepatozoon is the most widespread of the four genera that parasitize reptiles by infecting red blood cells. The Hepatozoon lifecycle requires blood-sucking invertebrates as vectors, and vector ... abundance can determine the parasite prevalence. To compare parasite prevalence between a large island and an islet without standing water, we analysed blood samples of the Madeiran wall lizard, Teira dugesii, at Praia Islet and Graciosa Island in the Azores, Portugal. We found a comparatively low prevalence of Hepatozoon, belonging to a new genetic line. The prevalence of this new parasite on the larger Graciosa Island was eight times higher than that for Praia Islet, which has no standing water sources. Our results are in line with a generally higher prevalence of blood parasites in sites with higher vector abundance.