Table 1.

The known responses of selected environmentally motile parasitic nematode infective larvae to host-emitted chemical attractants and thermosensory cues. The behaviors listed are those that have been described for iL3s of the indicated species; behaviors not listed either have not been tested or have been tested but not observed. The chemical attractants listed include only known chemical attractants for iL3s prior to host infection.

Nematode Species	Hosts	Infection Mode	Chemical Attractants	Temperature-Driven Behaviors	References
Necator americanus	humans	skin penetration	NaCl	arousal positive thermotaxis skin penetration	Haas et al., 2005a,b Koga et al., 2004
Ancylostoma duodenale	humans	skin penetration oral infection		arousal positive thermotaxis skin penetration nictation	Haas et al., 2005a,b
Ancylostoma ceylanicum	humans dogs cats other carnivores	skin penetration oral infection		positive thermotaxis negative thermotaxis migration speed altered path curvature	Bryant et al., 2018
Ancylostoma caninum	dogs	skin penetration oral infection	serum skin extract	arousal positive thermotaxis skin penetration nictation	Bhopale et al., 2001 Granzer and Haas, 1991 Vetter et al., 1985 Wauters et al., 1982 Zietse et al., 1981
Strongyloides stercoralis	humans primates dogs	skin penetration	host odorants skin extract serum NaCl sweat	arousal positive thermotaxis negative thermotaxis migration speed altered path curvature	Bryant et al., 2018 Castelletto et al., 2014 Forbes et al., 2003, 2004 Koga et al., 2005 Lopez et al., 2000 Safer et al., 2007
Strongyloides ratti	rats	skin penetration	host odorants serum NaCl	arousal positive thermotaxis negative thermotaxis skin penetration altered path curvature	Barrett, 1968 Bryant et al., 2018 Castelletto et al., 2014 Koga and Tada, 2000 Lee et al., 2016 Sakura and Uga, 2010 Tada et al., 1997 Tobata-Kudo et al., 2000a,b
Nippostrongylus brasiliensis	rats	skin penetration	host odorants	arousal positive thermotaxis negative thermotaxis altered path curvature	Bryant et al., 2018 Castelletto et al., 2014 Parker and Haley, 1960
Heligmosomoides polygyrus	mice	oral infection	host odorants fecal odor urine skin extract CO2	positive thermotaxis negative thermotaxis	Bryant et al., 2018 Hernandez and Sukhdeo, 1995 Ruiz et al., 2017
Haemonchus contortus	ruminants	oral infection	host odorants CO2	thermotaxis toward previous cultivation temperature	Castelletto et al., 2014 Li et al., 2000a, 2000b Ruiz et al., 2017