Dry preservation of Toxocara vitulorum by plastination technique

The most widely adopted technique to preserve the gross specimen of the parasite is immersions and storage in liquid preservatives. The present study aimed to describe the dry method of the preservation of Toxocara vitulorum using plastination technique.

Acetone dehydrated parasites were incubated at -20°C for 1 month in five different plastination solutions, prepared by mixing melamine and turpentine oil with clove oil (MTCl)/chloroform (MTC)/isopropanol (MTI)/benzene (MTB)/xylene (MTX) in 1:1:1 ratio to infiltrate the polymer. Technical personnel was asked to assign weekly score for dryness, stickiness, shrinkage, glossiness, flexibility, and odor of the prepared model on a 5-point scale.

Overall, the plastinated parasites were dry, non-sticky, glossy, odorless, chemical-free, harmless, to some extent flexible, with detectable morphological structure including natural form but lost their natural color, and cuticle became translucent. A varying level of shrinkage was noted in all types of plastinated model, but it was least in MTCl model. One month post-plastination, the mean evaluation score for glossiness was maximum in the parasite plastinated in MTCl solution (4.50±0.17), followed by MTC (3.72±0.32), MTX (3.56±0.38), MTB (2.83±0.37), and MTI (2.31±0.33). Likewise, for flexibility, the score was maximum in the parasite plastinated in MTCl solution (4.36±0.16), followed by MTB (3.11±0.14), MTC (2.94±0.41), MTX (2.75±0.41), and MTI (1.97±0.28). The degree of dryness, stickiness, and odor of the prepared model varies non-significantly (p>0.05) with the polymer mixtures. Maximum shrinkage percentage in terms of length and width was 4.24% and 50%, respectively, in the parasites plastinated in MTB solution. Shrinkage percentage was minimal (1.81% in length and 25% in width) in the MTCl plastinated parasites. Shrinkage percentage in terms of dimension was statistically non-significant among the different polymer solutions. Plastinated models withstand the process of microbial decomposition. There were 5 and 11 odd points in favor of plastination and formalin preservation technique, respectively.

The prepared T. vitulorum model in MTCl can be used as an adjunct to the parasite preserve in 10% formalin solution. The plastination technique can be used as an alternative method of liquid preservation.