. ▁ ▁Mor ph ology ▁The ▁adult ▁par as ite ▁is ▁dor so vent r ally ▁fl atten ed , ▁tap ering ▁backwards ▁res emb ling ▁a ▁verte br ate ▁tongue , ▁thus , ▁insp iring ▁the ▁common ▁name ▁of ▁" t ong ue w orm ." ▁ ▁Phys ical ▁characteristics : ▁males : ▁ ▁in ▁length , ▁while ▁the ▁females ▁are ▁. ▁ ▁Be havior ▁and ▁reprodu ction ▁Both ▁male ▁and ▁females ▁are ▁required ▁to ▁mate ▁for ▁successful ▁reprodu ction . ▁M ales ▁choose ▁to ▁mate ▁with ▁females ▁that ▁are ▁close ▁to ▁their ▁own ▁size . ▁Fem ales ▁contain ▁hundreds ▁of ▁thousands ▁of ▁eggs . ▁ ▁Ep ide mi ology ▁In fection ▁of ▁C airo ▁dogs ▁var ies ▁from ▁male ▁to ▁female , ▁with ▁a ▁ratio ▁of ▁▁ 1 . 9 : 1 ▁( 5 8 . 9 7 % ▁and ▁ 3 0 . 7 7 %, ▁respectively ). ▁Pre val ence ▁of ▁in fection ▁rate ▁is ▁higher ▁during ▁spring ▁and ▁summer ▁( 6 6 . 6 7 % ), ▁compared ▁during ▁fall ▁and ▁winter , ▁which ▁constit utes ▁ 3 3 . 3 3 % ▁of ▁the ▁in fection ▁rate . ▁The ▁probable ▁source ▁of ▁can ine ▁in fe ctions ▁is ▁inf ected ▁l ym ph ▁nodes ▁of ▁cattle , ▁sheep , ▁go ats , ▁and / or ▁cam els , ▁which ▁produce ▁the ▁sympt oms ▁of ▁hal z oun ▁and ▁the ▁mar r ara ▁synd rome ▁in ▁man ▁when ▁consum ed ▁raw   . ▁ ▁Geographic ▁range L .