Illustrated Articles

  • Lotilaner is used to treat and prevent flea infestations and treat and control tick infestations in dogs and cats. After being administered to a pet, lotilaner is distributed throughout the body. When fleas or ticks bite the dog or cat, they are exposed to the drug and killed during their blood meal.

  • Lufenuron is a medication that controls flea infestations in dogs, cats, rabbits, and ferrets. It is given by mouth in the form of a tablet or liquid to dogs, cats, rabbits, and ferrets. It may also be given by injection to cats. Side effects are uncommon but may include vomiting, diarrhea, lack of appetite, tiredness, reddening of the skin, or itchiness. Do not use in pets that are allergic to it. If a negative reaction occurs, please call your veterinary office.

  • Lumbosacral disease, or cauda equina syndrome, is caused by the narrowing of the spinal canal and results in compression of the spinal nerve roots; pressure on the nerves that exit the spine cause the clinical signs. This pressure may be due to a narrowed spinal canal caused by arthritis, intervertebral disc herniation, an infection in the disc, trauma, congenital malformation, or a spinal tumor. Dogs with lumbosacral disease are in pain. If the clinical signs and radiographs suggest lumbosacral disease, advanced imaging such as MRI or CT is recommended to make a diagnosis. Treatment involves either conservative medical treatment or surgical intervention.

  • Lung flukes in North America are parasites called Paragonimus kellicotti that infect the lungs of dogs after they have eaten an infected crayfish or rodents that have eaten infected crayfish. Eggs are then released by the parasite into the dog’s sputum to be coughed out or swallowed and released in the feces to continue the life cycle. Lung flukes can be found anywhere in North America but more commonly around the Mississippi River and Great Lakes. Infected dogs can be symptom-free or may develop cough with sometimes bloody mucus, pneumonia, pneumothorax, lethargy and weakness. Diagnosis can include locating eggs of the parasite from feces or mucus from the lungs. X-rays can also reveal cysts in the lungs caused by the parasite. Treatment requires one of 2 commonly used anti-parasitic medications: Praziquantel or Fenbendazole. Although zoonotic, these parasites won’t transmit directly from dogs to humans.

  • Lung tumors are considered rare in cats and dogs. Many pets may not show symptoms at first, and a tumor may be found coincidentally. Depending on the type and stage of cancer, treatment may be possible; otherwise, symptomatic supportive care may be an alternative option.

  • There are many species of lungworm that can cause respiratory problems in dogs. Infection is acquired through either: ingestion of an intermediate host such as snails or slugs, ingestion of animals that have been infected by eating these animals or depending on the species, from an infected dog by contact with saliva, nasal discharge, or contaminated food and water bowls. Lungworms can be found throughout North America and the world with certain species seen in certain areas. Clincal signs can range from asymptomatic to tachypnea, coughing, sneezing, wheezing, respiratory distress or exercise intolerance. The degree of clinical signs is usually proportional to the strength of the dog’s immune system. Diagnosis involves history, physical exam, x-rays and organism identification through either baermann fecal examination or BAL/bronchoscopy. Treatment involves use of specific antiparasitic drugs for various lengths of time depending on type and severity of infection. Prognosis is good but re-infection can occur.

  • A luxating patella is a kneecap that moves out of its normal location, causing an affected dog to skip or hop on three legs. Many toy or small breed dogs, including the Maltese, Chihuahua, French Poodle, and Bichon Frise, have a genetic predisposition for a luxating patella. Surgery should be performed to prevent the development of arthritis or another knee injury.

  • The bacterium that causes Lyme disease can be transmitted to dogs through the bite of an infected tick, most commonly the deer tick (black-legged tick), which is found in the midwestern and eastern United States and throughout Canada. The disease typically causes pain and swelling in the affected dog's joints along with decreased appetite and fever. The kidneys are sometimes affected, in which case the disease is often fatal. Diagnostic testing, treatment, and ways to prevent Lyme disease in your dog, including instructions for tick removal, are explained in this handout.

  • Lymphatic tumors are rare in pets. Lymphangiomas are benign and lymphangiosarcomas are malignant and have a moderate-to-high metastatic potential. Patients with lymphatic tumors typically have severe edema or cavity effusions because of lymphatic obstruction and leakage. These types of tumors occur more frequently in young dogs and cats. Treatment usually involves surgical excision and chemotherapy may be used as a follow-up treatment in the case of lymphangiosarcomas.

  • Lymphocytic plasmacytic gastroenteritis is a form of inflammatory bowel disease. While the exact cause is not known, it is possible that the intestinal bacteria themselves may be involved in stimulating the immune response. Treatment may include nutrition management, immunosuppressive medications, and dietary supplementation of cobalamin, prebiotics, and probiotics.