Parasites in Cats PDF

PARASITES BY HOST: CAT  BY THE END OF THIS PRESENTATION, YOU SHOULD BE ABLE TO: Provide a differential list of parasites that cause the clinical signs reported in the host Generate a diagnostic plan to rule in or out parasites on the differential list, and what the e...

PARASITES BY HOST: CAT  BY THE END OF THIS PRESENTATION, YOU SHOULD BE ABLE TO: Provide a differential list of parasites that cause the clinical signs reported in the host Generate a diagnostic plan to rule in or out parasites on the differential list, and what the expected findings would be for each test Design a treatment plan depending on the parasite affecting the host Inform owners regarding methods of prevention of future infections by these parasites MY CAT IS ITCHING Arthropods > Arachnids > Acari > Astigmata > Sarcoptidae > Notoedres NOTOEDRES Long, unsegmented pedicels Anus on dorsal surface of body Causes mange in cats, rats, rabbits, and occasionally humans In cats, starts on pinnae, then spread to face, paws, and hindquarters Cause alopecia and hyperkeratosis Diagnosis: Skin scrape Treatment: Macrocyclic lactones, fipronil Arthropods > Arachnids > Acari > Prostigmata > Cheyletiella CHEYLETIELLA “Walking dandruff” Large papal claws M-shaped peritremes Cheyletiella blakei: Cats Survive longer off host than other mange mites, environment may be source of reinfestation Diagnosis: Flea comb, trichogram, superficial skin scrape Treatment: Macrocyclic lactones, fipronil MY CAT IS VOMITING Nematoda > Secernetea > Ascaridia (roundworms) > Toxocara TOXOC ARA Worldwide distribution Cream colored adults with cervical alae Live as adults in small intestine of mammals Toxocara cati in cats Life cycle similar to Toxocara canis Exception: Transplacental transmission does not happen Transmammary transmission can occur in naively infected queens Nematoda > Secernetea > Ascaridia (roundworms) > Toxocara TOXOC ARA C ATI Disease: Less potential for death than T. canis Potential zoonosis in humans Diagnosis: Adults in vomit or feces, eggs in fecal flotation Treatment: Pyrantel pamoate, piperazine, macrocyclic lactones, emodepside MY CAT HAS DIARRHEA  ACTIVE LEARNING ACTIVITY List some causes of diarrhea in cats, and what tests you could run to rule in or out your differentials. Protists > Excavata (flagellates) > Trichomonadida > Tritrichomonas TRITRICHOMONAS BLAGBURNI Lives in large intestine of cats Common in catteries and purebred cats Causes chronic diarrhea in cats younger than 2 years Many cats are asymptomatic Most cats have spontaneous resolution of diarrhea Can take up to 2 years though Diagnosis: Trophozoites in fecal smears, InPouch culture, PCR No approved treatments Off label ronidazole or metronidazole Treatment failures common Protists > SAR > Apicomplexa > Coccidians > Cystoisospora CYSTOISOSPORA SPP. Infection via ingestion of oocysts or paratenic hosts (in dogs and cats) Cat species: C. felis, C. rivolta Some disease in newborn kittens Usually resulting from change of environment Can cause diarrhea, weight loss, and rarely hemorrhage Cause lead to reshedding of Toxoplasma gondii oocysts Animals recover and develop immunity, but can continue shedding Treatment: Sulfadimethoxine Protists > Excavata (flagellates) > Diplomonadida > Giardia GIARDIA Common intestinal commensal organism Assemblage F: Cat Many cats considered subclinical Diagnosis: Cysts on direct smear or fecal flotation with zinc sulfate, ELISA Diagnosis can be difficult due to intermittent shedding Treatment: Metronidazole off label Do not use metronidazole in pregnant or lactating cats, or those with liver disease Nematoda > Secernetea > Strongylida (bursates) > Ancylostomatoidea (hookworms) ANCYLOSTOMATOIDEA (HOOKWORMS) Infection via direct ingestion of infective third stage larvae (L3) Skin penetration of L3 also possible Infection via ingestion of paratenic hosts (i.e. rodents, cockroaches) also possible Cats: Ancylostoma tubaeforme Three teeth Ancylostoma braziliense: Dogs and cats affected One tooth More common in southern U.S. Nematoda > Secernetea > Strongylida (bursates) > Ancylostomatoidea (hookworms) ANCYLOSTOMATOIDEA (HOOKWORMS) Disease: Can cause anemia, diarrhea, and weight loss Respiratory disease and pneumonia can develop Diagnosis: Thin-walled, morulated eggs (“strongyle-type”) on fecal flotation Peracutely infected neonates may not be shedding eggs Treatment: Anthelminthics should be started as soon as possible, starting around 2 weeks of age Macrocyclic lactones, pyrantel, emodepside Platyhelminths > Cestodes > Diphyllobothroidea (aquatic tapeworms) > Spirometra SPIROMETRA SPP. Worldwide distribution, most common in southeast Asia Cat and bobcat natural definitive hosts Plerocercoid (aka sparganum) develops in many animals (snakes, frogs, birds, NOT in fish) Disease: Adults in intestine usually do not cause disease Can see diarrhea, weight loss, and vomiting Diagnosis: Operculated eggs in fecal flotation or sedimentation, segments passed in feces Treatment: No approved treatment, praziquantel has been used off-label MY CAT IS SNEEZING Arthropods > Insecta > Diptera (flies) > Cyclorrhapha > Oestridae (botflies) > Cuterebra CUTEREBRA SPP. Third-stage larva large, dark-brown to black, with stout black spines Acquired from rodent and rabbit burrows Bots found in cervical subcutaneous connective tissue Can aberrantly migrate to ocular, nasal, oral regions, and brain Treatment Manual removal Topical imidacloprid or fipronil Ivermectin MY CAT IS COUGHING  ACTIVE LEARNING ACTIVITY Name some parasitic differentials for coughing in a cat, and what diagnostic tests you would like to run to rule these in or out. Nematoda > Secernetea > Strongylida (bursates) > Metastrongyloidea (lungworms) > Aelurostrongylus AELUROSTRONGYLUS Live as adults in lungs of cats Eggs deposited in nests in nodules within lung parenchyma Eggs hatch in lungs and first-stage larvae coughed up and swallowed Infective larvae develop in snails and slugs Cats likely infected through ingestion L3 in mice and bird paratenic hosts Disease: Usually no clinical signs Can cause coughing, anorexia, dyspnea Diagnosis: L1 detected in Baermann technique or fecal flotation (less often) Treatment: Ivermectin, selamectin, fenbendazole Nematoda > Secernetea > Spirurida > Spirurina > Filaroidea > Dirofilaria DIROFILARIA IMMITIS Cats typically have 1-3 adults Cats seldom microfilaremic Disease in cats: Range from asymptomatic to severe clinical signs Heartworm associated respiratory disease (HARD) Due to death of immature heartworms in the pulmonary vessels causing intense inflammation Coughing, wheezing, dyspnea Nematoda > Secernetea > Spirurida > Spirurina > Filaroidea > Dirofilaria DIROFILARIA IMMITIS Diagnosis often difficult Antigen test: low sensitivity due to low worm burdens Antibody test: positive result not definitive for mature adult infection Microfilaria check: microfilaremia transient or non-existent Treatment: Currently no specific therapy for asymptomatic cats Melarsomine treatment NOT recommended Microfilaricidal treatment NOT required Year-round heartworm prevention recommended Platyhelminths > Trematodes > Paragonimus PARAGONIMUS Paragonimus kellicotti present in U.S. around Mississippi River basin Infection through ingestion of metacercariae in crabs and crayfish Disease: Can cause chronic coughing Bullae can form and rupture, leading to pneumothorax Aberrant migration to viscera and brain reported Diagnosis: Fecal sedimentation or transtracheal wash Treatment: Fenbendazole, albendazole, praziquantel MY CAT IS YELLOW Platyhelminths > Trematodes > Platynosomum PLATYNOSOMUM FASTOSUM AKA Lizard poisoning disease Lives as adults in bile and pancreatic ducts of cats Common in southeastern U.S. and Caribbean Cats infected by either ingesting pill bugs or paratenic hosts (lizards, toads) Can cause acute and chronic cholangitis with lethargy, fever, hepatomegaly, abdominal distension, jaundice, vomiting, and diarrhea Associated with cholangiocarcinoma Diagnosis: Eggs in feces on sedimentation Treatment: Praziquantel, surgical removal Protists > SAR > Apicomplexa > Aconoidasida > Piroplasmorida > Cytauxzoon CYTAUXZOON Common in southern and southeastern U.S. Transmission via bite of Amblyomma americanum Causes rapid onset, often fatal disease in domestic cats Fever, anemia, icterus, pancytopenia, death Occlusion of vessels by macrophages distended with schizonts Diagnosis: Organisms in erythrocytes and macrophages Treatment: Atovaquone+azithromycin MY CAT IS BEHAVING STRANGELY Arthropods > Insecta > Diptera (flies) > Cyclorrhapha > Oestridae (botflies) > Cuterebra CUTEREBRA SPP. Feline ischemic encephalopathy (FIE): Thrombosis of middle cerebral artery due to migration or toxin secretion Ischemic necrosis, degeneration of superficial layers of cerebral cortex and parenchymal destruction Protists > SAR > Apicomplexa > Coccidians > Toxoplasma TOXOPLASMA GONDII Enteric coccidian of felids Only felids shed oocysts Disease: Clinical disease uncommon in immunocompetent cats Immunocompromised cats can act as paratenic hosts Tachyzoites can cause granulomatous inflammation in multiple organs Lymph node, heart, liver, lung, brain/spinal cord, eye Protists > SAR > Apicomplexa > Coccidians > Toxoplasma TOXOPLASMA GONDII Oocysts on fecal flotation rare Clinically symptomatic cats unlikely to shed oocysts Oocysts only shed once for 1-3 weeks following initial infection Treatment: No approved treatment, the following have been used successfully in ill cats: Clindamycin Pyrimethamine + sulfonamide Trimethoprim-sulfonamide PRACTICE QUESTIONS