Ectoparasites Notes PDF

CLINICAL PATHOLOGY I – Lecture Fleas Ctenocephalides canis “dog flea” Ctenocephalides felis “cat flea” Flea, the common name for the order Siphonaptera Live by consuming blood...

CLINICAL PATHOLOGY I – Lecture Fleas Ctenocephalides canis “dog flea” Ctenocephalides felis “cat flea” Flea, the common name for the order Siphonaptera Live by consuming blood Laterally flattened Strong claws Wingless Jump 50 to 100 times their body size Flea life cycle o Direct life cycle o DH=dog and cat o Adult fleas live on host typically near their lower back o Prefer locations where dogs and cats do less grooming o Other favorite hangout spots are Chest Abdomen Neck Legs Inguinal area *Fleas rarely live on head or tail area o Adults take blood meal mainly around the base of the tail and across the hips o After eating their blood meal, males and females mate, and the females lay eggs Egg laying occurs 1-2 days after the blood meal. The eggs fall off of the host and land in the environment Environment where flea eggs land is variable, but most likely will be where pets eat, rest, or sleep o Flea eggs Take anywhere from 2-12 day to hatch depending on environmental conditions Make up 50% of flea infestations Will die under 55 degrees F If they survive they will hatch into larva o Flea Larvae are 2-5 mm long and are an off white color with dark red guts eat any organic substance but prefer flea dirt (feces) from adult fleas survive best in a food rich environment with optimal humidity levels and darkness Maturation of flea larva takes anywhere from 7-45 day depending on environmental conditions Larvae make up 35% of flea infestations Mature larvae pupate  First step is to produce a cocoon Inside cocoon larva turn into a pupa in 2-3 days o Flea Pupae look like a miniature flea take 6-7 days to finally molt into an adult make up 8-10% of a flea infestation o Adult fleas emerge from the cocoon and the life cycle starts all over. Pathology o Anemia from heavy infestation o Flea allergy dermatitis Flea saliva is antigenic and irritating Causes intense pruritus Clinical signs o Droppings or “flea dirt” in hair coat or on surfaces in the home o Excessive scratching, licking or biting at skin. o Hair loss. o Scabs and hot spots o Pale gums o Tapeworms Diagnosis o Flea dirt examination (wet down on white paper product) o Cellophane tape procedure o Microscopic identification Treatment/Prevention o Many different ways of dealing with fleas o Must stop the life cycle not just kill the adult o Flea control for the home Flea sprays and powders for carpets Vacuum cleaners Flea sprays for inside the house Flea foggers and bombs Flea traps Diatomaceous earth o Flea control on the pet Spot-on Treatment ▪ Permethrin=Advantix II (not to be used in cats) ▪ Imidacloprid=Advantage (ok in cats) ▪ Fipronil=Frontline plus Oral flea medications ▪ Nitenpyram Flea sprays  Flea shampoos Flea combs  CLINICAL PATHOLOGY – Lecture Ticks Classification of ticks o Kingdom= Animalia o Phylum=Arthropoda o Class=Arachnid o Order=Acarina o Family=Ixodida (hard ticks) o Family= Argasidae (soft ticks) Genus and species that we already learned Rhipicephalus sanguineus: “Brown dog tick” Dermacentor variabilis: “American dog tick or wood tick” Amblyomma americanum: “Lone star tick” Amblyomma maculatum: “Gulf Coast tick” Ixodes scapularis:“ Deer tick” Boophilus annulatus: “Texas cattle fever tick” Otobius megnini: “Spinose ear tick” Body Morphology and Parts o Two body regions Capitulum-the cranial portion containing mouthparts ▪ Mouthparts include: 2 palps, 2 chelicerae, 1 hypostome Palps- Sheath that protects the ticks hypostome. Move out of the way during feeding and don't pierce the host's skin Chelicerae-Knife like. Used to cut a hole in the hosts skin Hypostome-Tool used by tick to suck the blood Idiosoma-Caudal portion containing most internal organs ▪ Scutum- dorsal plate or shield covering Females- only covers the cranial portion of the body of hard ticks Males-covers the entire body of hard tick ▪ Festoons-Rectangular grooves seen on the caudal edge of some hard ticks o Body shapes (nonengorged ticks only) Teardrop Oval  Rounded Tick life cycle All ticks undergo four basic life stages: egg, larva, nymph, adult o Adult-Largest life stage Sexual reproduction-males and females copulate on host Blood meal usually necessary for egg production in females Female drops to the ground to lay eggs in the soil Female lays several thousand eggs at one time o Egg-Eggs can be deposited in the environment, typically in the dirt, but can also be laid in a house (common with brown dog tick). o Larva- Hatch from the egg 6 legged Will find a host to feed off of and then molt o Nymph-molted from larvae Have eight legs and look like tiny adults Will continue to feed and molt to an adult And the cycle starts all over again How many hosts during the life cycle Ticks will either have 1, 2, or 3 hosts depending on the species of the tick o One-host ticks Boophilus annulatus: “Texas cattle fever tick Larvae attach onto the preferred host and feed They remain on that host and molt into a nymph and then an adult Only adult will drop off to lay eggs or die o Two-host ticks Rhipicephalus sanguineus “Brown dog tick” Larvae attach onto the preferred host and feed They remain on that host and molt into a nymph Nymph feeds on that host but drops off and turns into adult Adult finds new host to feed off of and reproduce  o Three host ticks Dermacentor variabilis: “American dog tick or wood tick” Ixodes scapularis:“ Deer tick” Larvae attach onto the preferred host and feed Larvae drop off and molt into nymph Nymph finds a new host, feeds, and drops off Nymph molts to adult which then finds a third host to feed off of and reproduce Disease Transmission Dermacentor variabilis: Rocky Mountain spotted fever Tularemia Tick paralysis Ehrlichiosis Amblyomma americanum: Rocky Mountain spotted fever Tularemia Tick paralysis Ehrlichiosis Ixodes scapularis: Lyme disease Babesiosis Tick paralysis Ehrlichiosis Rhipicephalus sanguineus: Rocky Mountain spotted fever Babesiosis Tick paralysis Ehrlichiosis Haeomobartonellosis Clinical signs Ticks that do not transmit disease o Certain tick species do not transmit diseases but can still cause issues Visually seeing them Irritation of the skin Anemia in severe infestations  Just plain annoying to your pet Tick Paralysis o Caused by toxins released in tick saliva o Clinical signs appear around 6-9 days after a tick has attached to the skin o Seen more often in dogs than cats in the United States Vomiting or regurgitation Unsteadiness Weakness, especially in the hind limbs Partial loss of muscle movements (paresis) Complete loss of muscle movement (paralysis), commonly seen in advanced disease state Poor reflexes to complete loss of reflex Low muscle tone (hypotonia) Dysphagia Dysphonia Asphyxia due to respiratory muscle paralysis in severely affected animals Excessive drooling Megaesophagus Mydriasis (Excessive dilatation of pupil in the eye) Hypertension Tachycardia Rocky Mountain Spotted Fever o Caused by Rickettsia rickettsia a gram negative coccobacillus bacteria o Clinical signs will usually manifest in 5 days after tick attachment starting with a fever Lethargy Depression Anorexia Cardiac arrhythmia Discolored spots along the skin, often bruised or purplish in color Inability to walk normally, loss of coordination (ataxia)  Swelling or edema in the limbs Bleeding that occurs suddenly, most often from the nose, or in the stools Difficulty with blood clotting, which can lead to shock or death Blood in the urine Inflammation, hemorrhage, or conjunctivitis in the mucosal membranes, most commonly in the eyes Swollen lymph nodes Pain in the eyes Lyme disease o Caused by Borrelia burgdorferi bacterium o Can be transmitted within 48 hours of a deer tick attaching to the host o Causes recurrent lameness in dogs Stiff walk with an arched back Sensitivity to touch Difficulty breathing Fever, lack of appetite, and depression Superficial lymph nodes close to the site of the infecting tick bite may be swollen Ehrlichiosis o Caused by Ehrlichia canis in dogs o Rickettsia obligate intercellular bacteria in the anaplasmataceae family o Effects the monocytes of dogs and symptoms present around 1-3 weeks after bite from infected tick o Bacteria may be present for months or years without clinical symptoms o Acute infection symptoms Enlarged lymph nodes Weakness Lethargy Depression Anorexia Dyspnea Limb edema  o Chronic infection symptoms Abnormal bleeding ie…nose bleeds Severe weight loss Fever Dyspnea due to inflammation of the lungs Joint inflammation and pain Lack of coordination Head tilt Potential seizures Eye pain Anemia Kidney failure Paralysis Babesiosis o Protozoal single celled parasitic organism Lack of energy Lack of appetite Weight loss Fever Pale mucous membranes Icterus/Jaundice Discolored stool Colored urine Enlarged abdomen Haemobartonellosis o Mycoplasma bacteria o 50 percent of those infected will have sudden onset of fever Depression Weakness Lack of appetite  Whitish to pale purple gums Splenomegaly Jaundice Urinary tract infections (cats mainly) Infertility in dogs (both genders) Diagnosis o History of ticks found on pets o Signs and symptoms o Serological testing (not all tick-borne diseases) o Blood smear conformation (not all tick-borne diseases) Prevention o Stay out of areas with ticks o Proper tick removal o Spot on treatments o Advantix II o Frontline o Oral medication o NexGard® (afoxolaner)