1. Exploring cryopreservation alternatives for Dirofilaria immitis microfilariae.
- Author
-
Sturiale E, De Benedetto G, Napoli E, Varet J, Lemaire A, Origgi F, Gaglio G, and Brianti E
- Abstract
Canine Heartworm Disease, caused by Dirofilaria immitis, primarily affects canids and felids. The earliest studies on cryopreservation were carried out at -70°C, achieving acceptable survival rates, however microfilariae (mf) showed alterations both in morphology and motility. Thereafter, liquid nitrogen was used representing an excellent tool for long-term preservation, albeit it is expensive and requires trained personnel. Accordingly, the aim of this study was to develop a protocol for cryopreservation of D. immitis mf at -80°C feasible to laboratories with limited specialized equipment. The cryoprotectant medium was composed by 5 % dimethyl sulfoxide, 20 % of newborn calf serum and 75 % of saline solution. At Study Day (SD) 0 whole blood from a D. immitis naturally infected dog was diluted with the medium at a ratio of 1:1 and stored at -80°C using a freezing container (Nalgene® Mr. Frosty® Cryo 1°C). On the SD1 and then once a month, one cryovial was thawed and examined for survival, motility, length and morphology of mf. On SD 1, the mf showed a survival rate of 99 %. By SD 120 the survival rate gradually decreased (up to 63 %) and a shift in motility patterns between the "medium" and "slow" classes, was observed. On SD 150, the survival rate exceeded 50 % and mf did not exhibit detectable morphological alterations; however, a reduction in length was observed. This study marks the first protocol where the -80°C freezer has been employed for cryopreservation of D. immitis, integrating the application of cryoprotectants and novel techniques for gradual temperature transition., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2024
- Full Text
- View/download PDF