Importance of Parasitology
12.1	Introduction: The Goodness of Parasites?Lincicome and his co-workers performed numerous experiments using various protozoan and nematode parasites
of rats and mice that are summarised in Lincicome (1971).For example, the rickettsia Anaplasma phagocytophilum enhances the survival of its tick vector, Ixodes scapularis, by inducing the expression of a gene that codes to produce antifreeze glycoproteins (Neelakanta et al. 2010).Another instance of
 
parasites enhancing the survival of their host is that of worker caste ants of
Temnothorax nylanderi infected with the larval stage of the
tapeworm Anomotaenia brevis (Beros et al. 2021).Within this chapter, we will consider some of the ways in which parasitesare useful to us. For example, some helminths have potential for the
treatment of certain autoimmune diseases whilst blowfly larvae andleeches are commonly employed in biosurgery.The term 'the goodness of parasites' was initially coined by David Lincicome whilst he was Professor of Zoology at Howard
University, Washington, DC, USA.Nevertheless, it is increasingly apparent that parasites sometimes prove useful to their hosts and that low parasite burdens may help maintain a healthy immune system.He observedthat the parasitised animals often performed better in terms of body weight gain, longevity, and certain physiological parameters than those
that were parasite-free.Anaplasma phagocytophilum is an intracellular parasite that infects humans, dogs, and various other mammals.Parasites are also
potentially useful sources of novel pharmacologically active substances.Parasites have even been implicated in criminalinvestigations and some workers have seen fit to coin the term 'forensic parasitology'.