Submitted to: Journal of Parasitology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/12/2009
Publication Date: 3/5/2009
Citation: Masuoka, P.M., Burke, R., Colaccico, M., Razuri, H., Hill, D.E., Murrell, K. 2009. Predicted geographic ranges for North American sylvatic Trichinella. Journal of Parasitology. 95(4):829-837. Interpretive Summary: In this paper, we discuss our use of the maximum entropy (Maxent) approach to modeling to develop a predictive Trichinella species range map based on less than abundant confirmed species records from sylvatic hosts in North America (Canada, USA, and Mexico) accumulated over the past 55 years. Temperature and land cover characteristics for T. spiralis and T. murrelli are distinctly different from that of T. nativa and T6, particularly in mean minimum January temperatures and maximum July temperatures. The occurrence of only T. nativa and T6 in the most northern latitudes of North America is believed to be due to the high resistance of the muscle larvae to freezing, in contrast to T. spiralis and T. murrelli which are relatively intolerant to freezing. The lack of such freeze-tolerance in T. murrelli and T. spiralis is probably a critical factor in restricting their ranges to southern latitudes, with mean minimum January temperatures not lower than -7 to -8 degrees C.
Technical Abstract: Because of a lack of comprehensive surveys, the geographic distributions of the North American species of Trichinella (T. nativa and its variant T6, T. murrelli, and T. spiralis) are poorly characterized. These species are potentially zoonotic, and biogeographical information is critical to monitoring their status and any distribution changes due to climatic and man-made environmental impacts. Therefore, it is important to more precisely identify their current geographical ranges. New programs using climate, land cover and elevation have been developed in conservation biology for modeling animal species distributions. The maximum entropy model (Maxent) is particularly useful because of its ability to predict distribution ranges with varying levels of probability using limited location records. The Maxent model was used to generate predicted ranges for the North American Trichinella using location records for confirmed species collected over 55 years throughout North America. The resulting prediction models were shown to be robust, and the species maps created are presented.