methoprene and Parasitemia

Certain tick species including Ixodes holocyclus can inoculate neurotoxins that induce a rapid, ascending flaccid paralysis in animals. Rhipicephalus sanguineus, the most widespread tick of dogs, is recognized as a vector of several pathogens causing diseases in dogs and humans. A single report suggests its role as cause of paralysis in dogs. This study presents the clinical history of 14 young dogs heavily infested by R. sanguineus (intensity of infestation, 63-328) in an endemic area of southern Italy. During May to June of 2011, dogs were presented at the clinical examination with neurological signs of different degrees (e.g., hind limb ataxia, generalized lethargy, and difficulty in movements). All animals were treated with acaricides and by manual tick removal but ten of them died within a day, displaying neurological signs. The other 4 dogs recovered within 3 days with acaricidal and supportive treatment. Twelve dogs were positive by blood smear examination for Hepatozoon canis with a high parasitemia, two also for Babesia vogeli and two were negative for hemoparasites. Low-grade thrombocytopenia, hypoalbuminemia, and pancytopenia were the haematological alterations most frequently recorded. Other causes of neurological disease in dogs were excluded and the diagnosis of tick paralysis by R. sanguineus was confirmed (ex juvantibus) by early and complete recovery of 4 dogs following acaricidal treatment and tick removal.

Topics: Acaricides; Animals; Dog Diseases; Dogs; Female; Italy; Male; Methoprene; Parasitemia; Pyrazoles; Rhipicephalus sanguineus; Tick Infestations; Tick Paralysis

The effects of methoprene, a juvenile hormone analogue (JHA), on Trypanosoma cruzi bloodstream trypomastigotes (Tulahuen strain, Tul 2 stock) were studied. It was observed that 150microM of methoprene in in vitro experiments cause cellular death of T. cruzi. In contrast, methoprene was not able to clear bloodstream trypomastigotes in in vivo experiments, but it was observed a decrease of parasitemia levels of infected mice treated with 200microg of methoprene/mouse/day during 5 days. According to these results and the low toxicity of methoprene, we suggest that this compound will serve as an effective agent to sterilize blood for transfusions.

Topics: Animals; Blood Transfusion; Chagas Disease; Juvenile Hormones; Male; Methoprene; Mice; Parasitemia; Sterilization; Trypanocidal Agents; Trypanosoma cruzi