Lung histopathology, radiography, high-resolution computed tomography, and bronchio-alveolar lavage cytology are altered by Toxocara cati infection in cats and is independent of development of adult intestinal parasites.

This study presents clinical findings after oral ingestion of Toxocara cati eggs which resulted in rapid pulmonary lung migration and parenchymal disease, noted on clinically relevant diagnostic methods. Further, the study investigated the efficacy of pre-infection applications of preventative medication on larval migration through the lungs. A third aim of the study was to determine if adult cats infected with T. cati developed lung disease. Cats in infected groups were administered five oral doses of L3 T. cati larvae. Four-month-old specific pathogen free (SPF) kittens were divided into three groups (six per group): an infected untreated group, an uninfected untreated control group, and an infected treated group (topical moxidectin and imidacloprid, Advantage Multi for Cats, Bayer Healthcare LLC). Six 2- to 3-year-old adult multiparous female SPF cats were an infected untreated adult group. The cats were evaluated by serial CBCs, bronchial-alveolar lavage (BAL), fecal examinations, thoracic radiographs, and thoracic computed tomography (CT) scans and were euthanized 65 days after the initial infection. Adult T. cati were recovered in infected untreated kittens (5/6) and infected untreated adults (5/6) in numbers consistent with natural infections. Eggs were identified in the feces of most but not all cats with adult worm infections. No adult worms were identified in the uninfected controls or the infected treated group. All cats in the infected groups, including treated cats and untreated cats without adult worms, had lung pathology based on evaluation of radiography, CT scans, and histopathology. The infected cats demonstrated a transient peripheral eosinophilia and marked eosinophilic BAL cytology, but normal bronchial reactivity based on in vivo CT and in vitro ring studies. Lung lesions initially identified by CT on day 11 were progressive. Thoracic radiographs in infected cats had a diffuse bronchial-interstitial pattern and enlarged pulmonary arteries. Pulmonary arterial, bronchial, and interstitial disease were prominent histological findings. Infected treated cats had a subtle attenuation but not prevention of lung disease compared to infected cats. Significant lung disease in kittens and adult cats is associated with the early arrival of T. cati larvae in the lungs and is independent of the development of adult worms in the intestine. These data suggest that while the medical prevention of the development of adult parasites after oral exposure to T. cati is obviously beneficial, this practice even with good client compliance will not prevent the development of lung disease which can alter clinical diagnostic methods.

[1]  S. W. Nielsen,et al.  Ascariasis causing pulmonary arterial hyperplasia in cats. , 1970, Research in veterinary science.

[2]  P. McDonough,et al.  Prevalence of enteric zoonotic agents in cats less than 1 year old in central New York State. , 2001, Journal of veterinary internal medicine.

[3]  A. Fahrion,et al.  Toxocara eggs shed by dogs and cats and their molecular and morphometric species-specific identification: is the finding of T. cati eggs shed by dogs of epidemiological relevance? , 2011, Veterinary parasitology.

[4]  V. Mircean,et al.  Prevalence of endoparasites in household cat (Felis catus) populations from Transylvania (Romania) and association with risk factors. , 2010, Veterinary parasitology.

[5]  T. Schnieder,et al.  Larval development of Toxocara canis in dogs. , 2011, Veterinary parasitology.

[6]  S. Borthakur,et al.  Gastrointestinal helminthes in stray cats (Felis catus) from Aizawl, Mizoram, India. , 2011, The Southeast Asian journal of tropical medicine and public health.

[7]  R. Arther,et al.  Imidacloprid/moxidectin topical solution for the prevention of heartworm disease and the treatment and control of flea and intestinal nematodes of cats. , 2005, Veterinary parasitology.

[8]  T. Schnieder,et al.  Vertical transmission of Toxocara cati Schrank 1788 (Anisakidae) in the cat , 2003, Parasitology Research.

[9]  T. Nolan,et al.  Endoparasite prevalence and recurrence across different age groups of dogs and cats. , 2009, Veterinary parasitology.

[10]  I. Martínez-Barbabosa,et al.  The prevalence of Toxocara cati in domestic cats in Mexico City. , 2003, Veterinary parasitology.

[11]  J. Malone,et al.  World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) second edition of guidelines for evaluating the efficacy of anthelmintics in ruminants (bovine, ovine, caprine) , 1995, Veterinary parasitology.

[12]  Christian Epe,et al.  Intestinal nematodes: biology and control. , 2009, The Veterinary clinics of North America. Small animal practice.

[13]  D. Aucoin,et al.  Prevalence of intestinal parasites in pet dogs in the United States. , 2009, Veterinary parasitology.

[14]  T. Nolan,et al.  Time series analysis of the prevalence of endoparasitic infections in cats and dogs presented to a veterinary teaching hospital. , 1995, Veterinary parasitology.

[15]  C. Genchi,et al.  Efficacy of selamectin against experimentally induced and naturally acquired infections of Toxocara cati and Ancylostoma tubaeforme in cats. , 2000, Veterinary parasitology.

[16]  T. Kumagai,et al.  Loop-Mediated Isothermal Amplification Assay for Detection and Discrimination of Toxocara canis and Toxocara cati Eggs Directly From Sand Samples , 2010, The Journal of parasitology.

[17]  M. Sullivan,et al.  Thoracic high-resolution computed tomographic findings in dogs with canine idiopathic pulmonary fibrosis. , 2005, The Journal of small animal practice.

[18]  A. R. Dillon,et al.  Activity of pulmonary intravascular macrophages in cats and dogs with and without adult Dirofilaria immitis. , 2008, Veterinary parasitology.

[19]  C. H. Courtney,et al.  World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guidelines for evaluating the efficacy of anthelmintics for dogs and cats. , 1994, Veterinary parasitology.

[20]  G. Altreuther,et al.  Evaluation of the efficacy of emodepside plus praziquantel topical solution against ascarid infections (Toxocara cati or Toxascaris leonina) in cats , 2005, Parasitology Research.

[21]  Eric A. Hoffman,et al.  Automatic lung segmentation for accurate quantitation of volumetric X-ray CT images , 2001, IEEE Transactions on Medical Imaging.

[22]  M. Ribicich,et al.  Prevalence of Toxocara cati and other parasites in cats' faeces collected from the open spaces of public institutions: Buenos Aires, Argentina. , 2006, Veterinary parasitology.

[23]  E. Breitschwerdt,et al.  Seroprevalences of antibodies against Bartonella henselae and Toxoplasma gondii and fecal shedding of Cryptosporidium spp, Giardia spp, and Toxocara cati in feral and pet domestic cats. , 2004, Journal of the American Veterinary Medical Association.

[24]  O. Duru,et al.  Antiparasitic efficiency of Artemisia absinthium on Toxocara cati in naturally infected cats. , 2011, Turkiye parazitolojii dergisi.

[25]  K. Krieger,et al.  Efficacy of Procox® Oral Suspension for Dogs (0.1% Emodepside and 2% Toltrazuril) against Experimental Nematode (Toxocara cati and Ancylostoma tubaeforme) Infections in Cats , 2011, Parasitology Research.

[26]  T. Schnieder,et al.  Treatment and Prevention of Vertical Transmission of Toxocara cati in Cats with an Emodepside/Praziquantel Spot-on Formulation , 2009, Parasitology Research.

[27]  D. Bowman,et al.  Efficacy of a milbemycin oxime-praziquantel combination product against adult and immature stages of Toxocara cati in cats and kittens after induced infection. , 2007, Veterinary parasitology.

[28]  A. R. Dillon,et al.  High-resolution computed tomography bronchial lumen to pulmonary artery diameter ratio in anesthetized ventilated cats with normal lungs. , 2012, Veterinary radiology & ultrasound : the official journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association.

[29]  Q. Zhong,et al.  Isometric responses of isolated intrapulmonary bronchioles from cats with and without adult heartworm infection. , 2012, American journal of veterinary research.

[30]  I. Ramsey,et al.  Thoracic high-resolution computed tomography in the diagnosis of metastatic carcinoma. , 2004, The Journal of small animal practice.

[31]  L. Glickman,et al.  Estimated prevalence of nematode parasitism among pet cats in the United States. , 2006, Journal of the American Veterinary Medical Association.

[32]  N. Otsu A threshold selection method from gray level histograms , 1979 .

[33]  Raúl San José Estépar,et al.  Interobserver variability in the determination of upper lobe-predominant emphysema. , 2007, Chest.

[34]  J. Sprent The life history and development of Toxocara cati (Schrank 1788) in the domestic cat , 1956, Parasitology.

[35]  D. Lindsay,et al.  Prevalence of canine parasites based on fecal flotation , 1996 .

[36]  Dwight D. Bowman,et al.  Georgis' Parasitology for Veterinarians , 1995 .