ZACH MESS MAY 2012 Dirofilaria immitis

Background Common name:  Heartworm Definitive host:  Canids  Foxes, wolves, dogs, etc.  Cats (less persistent)  Other mammals Accidental host:  Humans Transmission  Mosquito bite Geographic Distribution  World wide  More common in warm climates (mosquitoes)

Characteristics Adults  Very long and thin  Thin alae  3 caudal papillae  Can live 5-10  Viviparous  Gives live birth Males  12-19cm long  Spiral or coiled tail Females  23-30cm long  Vagina just posterior to esophagus Juveniles (microfilariae)  um  Long, pointed tails

Adult Worms

Microfilariae

Life Cycle

Life Cycle Breakdown 3 rd stage filarial larvae enter body when mosquito bites travels through blood stream molts once to 4 th stage larvae (L4) molts again to adult adults reside in pulmonary arteries female worms produce microfilariae which reside in peripheral blood mosquito bites and picks up microfilariae with blood-meal migrate from mid-gut to Malpighian tubules (in abdomen) microfilariae develpe to 1 st stage larvae, then to L2 and L3 L3 migrate to proboscis (mosquito pokey thing) mosquito bites and deposit L3 to host **microfilariae can be cross placental barrier to puppies but adult worms will not form, no intermediate host interaction**

Human Pathway **follows same pathway in humans** Adults end up in smaller blood vessels in lungs build up causing “coin-lesions”

Symptoms Dogs / Cats  Pulmonary artery blockage  Coughing  Difficulty breathing  Coughing up blood  Exhaustion  Fainting  Weight loss  Heavy infection ~ 25 worms  Further infection can fill cavities of heart

Symptoms Humans  Most are asymptomatic  Cough  coughing up blood  fever  chest pain  Pulmonary dirofilariasis  Dying worms produce granulomas in pulmonary arteries  Pleural effusion  Excess fluid between tissue lining lungs and chest cavity  Inflamation caused by dying adult worms  Coin lesions in pulmonary arteries

Diagnosis Blood tests  Observe microfiliariae in blood Parasitic antigen testin Identification of coin lesions in lungs and pulmonary arteries  Lesions observed in chest Xray  Mostly found by accident since most are asymptomatic Identification of nodules under skin Examination of inflamed tissue

Treatment Dogs / Cats  Immiticide® (Adulticide)  Anti-inflamatory drugs  Surgical removal (if necessary) Humans  Surgical removal of lung granulomas and inflamed nodules under skin  Drugs aren’t usually needed

Prevention Dogs / Cats  Anti heartworm medications   Flee, tick, and mosquito medications Humans  Vector control  Bug spray

Work Cited pdf 11.pdf diseases/heartworm-disease/pathogen/ diseases/heartworm-disease/pathogen/ resources/heartworm.html#signs