Tracheal collapse causes a chronic dry cough that sounds similar to a goose honk. The disease tends to get worse with time. Tracheal collapse can’t be cured, but for most patients, medical treatment reduces the severity of the cough. In the most serious cases, tracheal collapse interferes with breathing and requires emergency care.
 
Tracheal collapse can affect dogs of any breed but is most common in small-breed dogs like Yorkshire terriers and Pomeranians. It’s rare in cats.
 
Cause
The trachea (windpipe) is a tube held open by rings of cartilage. In animals with tracheal collapse, the cartilage rings soften and become weakened over time. The cartilage rings lose their ability to hold the trachea open and the trachea flattens during breathing or coughing, blocking the flow of air.
 
The severity of the signs depends on the percentage of airway that’s blocked. The signs also partly depend on the location of the affected section of trachea: outside the rib cage (in the neck) versus within the rib cage.
 
In dogs with tracheal collapse, coughing is made worse by pressure on the neck, excess weight, stress, excitement, exercise, respiratory irritants like smoke, and respiratory infections. Some dogs with tracheal collapse also have abnormalities of the larynx and the bronchi (airways inside the lungs). Chronic coughing causes airway inflammation, which in turn leads to more coughing.
 
Tracheal collapse and heart disease are both common in middle-aged and older small-breed dogs, so many dogs have both diseases at the same time. Both diseases cause coughing and exercise intolerance. Figuring out which disease is most responsible for the cough can be a bit of a diagnostic challenge.
 
Signs

• Harsh, dry, honking cough
• (Possibly) a cough that gets worse with pressure on the neck or with exercise
• Wheezing
• Exercise intolerance
• Blue or purple gums caused by low oxygen level (medical emergency)
• Collapse or fainting (medical emergency)

 
Diagnosis
Tracheal collapse is suspected on the basis of the patient’s history, the sound of the cough, and physical examination findings. A definite diagnosis is made with imaging studies. Radiographs (x-ray images) sometimes show a collapsed trachea and are also used to evaluate heart size and the appearance of the lungs. In many dogs the trachea collapses only on inhalation or only on exhalation, so fluoroscopy—an x-ray “movie”—can reveal collapse that doesn’t appear on radiographs. Tracheoscopy is examination of the inside of the trachea and bronchi with a fiber optic camera in an endoscopy tube. An advantage of tracheoscopy is that it allows samples from inside the trachea to be collected for laboratory analysis; a disadvantage is that it requires general anesthesia.
 
Dogs with tracheal collapse might have bloodwork to assess their overall condition, especially if they are older or have concerning clinical signs. Because the signs of tracheal collapse and heart disease overlap, dogs with suspected or known heart disease also benefit from echocardiography to evaluate heart function.
 
Treatment
Tracheal collapse isn’t curable, so medical treatment needs to continue for life. Medications chosen for an individual patient might include cough suppressants to break the cough cycle, corticosteroids to reduce airway inflammation, bronchodilators, and antianxiety medications or sedatives to reduce stress. The choice of medication can change over time as the dog’s disease progresses.
 
Nonmedical management is crucial for dogs with tracheal collapse and includes the following:

• Weight management
• Use of harness instead of leash and collar
• Elimination of respiratory irritants like smoke and scented air fresheners

 
Surgical procedures like tracheal stent placement are available for dogs with severe signs. However, surgical options don’t cure the underlying tracheal problem and might not eliminate the cough.
 
Image source: https://unsplash.com/photos/a-small-dog-standing-under-a-wooden-bench-HSs4t4TWPFg

Have you ever heard that pregnant people shouldn’t handle a cat’s litter box? This is because of the risk of toxoplasmosis. World Zoonoses Day, July 6, is a great time to talk about how this disease passes from animals to people and whether pregnant people really do get a 9-month pass on cleaning the litter box.
 
Zoonoses are diseases that are transmitted from nonhuman animals to humans. Toxoplasmosis is a zoonotic disease caused by infection with the protozoan parasite Toxoplasma gondii. Toxoplasmosis is one of the most common foodborne illnesses in people.
 
The people who should be most cautious about T gondii infection are those with compromised immune systems and those who are pregnant.
 
Toxoplasmosis in People
People With Healthy Immune Systems
People with healthy immune systems usually have no signs of T gondii infection and don’t know they’ve been infected. For those who develop signs, most have swollen lymph nodes or flu-like symptoms that get better on their own within a few weeks. Much less commonly, the infection can affect the eyes and cause vision loss.
 
Whether or not the initial infection causes any signs of illness, the parasites remain in the body in a dormant state. The infected person develops immunity to T gondii. However, if the person’s immune system becomes compromised (because of chemotherapy, organ transplantation, or AIDS, for example), the T gondii organisms are reactivated and cause illness.
 
People With Weakened Immune Systems
In people with compromised immunity, toxoplasmosis affects the brain, eyes, lungs, and other organs. Either a new infection or a reactivated infection can cause seizures, confusion, and coordination problems.
 
Fetuses Infected Before Birth
A fetus won’t become infected if the mother was infected with T gondii before getting pregnant. In this case the mother already has immunity and won’t pass the infection to the unborn child (as long as she has a healthy immune system).
 
If a mother is infected for the first time during or immediately before pregnancy, the fetus can be infected too because the mother doesn’t yet have immunity. Most people don’t know if they’ve been infected with T gondii in the past, so it’s safest for all pregnant people to take precautions to avoid infection.
 
The consequences of infection in an unborn child can be severe. The pregnancy might end in miscarriage or stillbirth, or the fetus might develop anatomic abnormalities. More commonly, infected infants have no signs of infection when they’re born. These individuals can develop vision loss or neurologic problems years later.
 
How People Are Infected

• Foodborne transmission: eating undercooked meat or shellfish; drinking contaminated water or unpasteurized goat milk
• Zoonotic transmission from cat feces: swallowing the parasite after handling cat litter and not washing hands; consuming produce contaminated with cat feces (for example, eating unwashed vegetables from a garden that a cat has used as a latrine)
• Transmission from newly infected mother to fetus
• Blood or organ donation from infected donor (rare)

 
Toxoplasmosis in Cats
Domestic cats and other felines are the only species that spread T gondii into the environment. Cats become infected after eating birds or rodents that have T gondii cysts in their bodies. Infected cats then shed T gondii oocysts (eggs) in the stool. The oocysts are not infective to other animals right away. After at least 1 day, the oocysts mature to a stage that can infect other animals. Infective oocysts can survive in the environment for years.
 
Most infected cats don’t have any signs of illness. Cats with compromised immune systems can develop disease similar to that of humans with compromised immune systems.
 
Identifying cats infected with T gondii is tricky. Cats shed oocysts in the stool for only a short time, so fecal tests aren’t reliable for diagnosing infection in cats. However, if a fecal test happens to show oocysts that look similar to T gondii, the cat’s owners should take precautions with the cat’s stool for a few weeks. A blood test showing that a cat has T gondii antibodies doesn’t tell us whether that cat is likely to start shedding oocysts that could put the family at risk.
 
Precautions
The CDC recommends these precautions to avoid toxoplasmosis:

• Cook meat and fish to an internal temperature high enough to kill T gondii organisms.
• Rinse fruits and vegetables.
• Don’t eat raw or undercooked shellfish or drink unpasteurized goat milk.
• Follow hand and kitchen hygiene precautions (wash with soap and water).
• Wear gloves when gardening; wash hands after handling soil that a cat might have defecated in.
• Cover outdoor sandboxes so cats don’t use them as giant litter boxes.
• Don’t feed cats raw or undercooked meat.
• Scoop the cat litter box daily; it takes more than 1 day for oocysts in the stool to become infective.
• See this CDC page for more: https://www.cdc.gov/toxoplasmosis/prevention/index.html

 
Pregnant people should also take these precautions:

• Have someone else clean the litter box if possible. If you need to handle the litter, wear disposable gloves and wash your hands afterward.
• Keep cats indoors to prevent them from hunting animals that might be carrying T gondii cysts.
• Don’t handle stray cats or kittens while you’re pregnant.
• Don’t get a new cat while you’re pregnant.

 
For More Information

• Toxoplasma gondii, Companion Animal Parasite Council website: https://capcvet.org/guidelines/toxoplasma-gondii/
• Toxoplasmosis, Centers for Disease Control and Prevention website: https://www.cdc.gov/toxoplasmosis/about/index.html

 
Image source: https://www.cdc.gov/dpdx/toxoplasmosis/index.html