Lungworm in Alpaca: Parasites That Cause Coughing and Weight Loss

Lungworm is a parasitic infection that affects the lungs and airways. In alpacas and llamas, the parasite most often discussed is Dictyocaulus filaria, a lungworm that can trigger inflammation in the bronchi and lung tissue. As irritation builds, an alpaca may develop a chronic cough, breathe faster than normal, or start losing body condition.

The disease is sometimes called verminous bronchitis or verminous pneumonia. That sounds dramatic, but the severity can vary a lot. Some alpacas have mild coughing and reduced thriftiness. Others develop more obvious respiratory distress, especially if there is a heavy parasite burden or a secondary bacterial infection.

Lungworm is considered uncommon in North American camelids compared with some other parasite problems, but it is still an important rule-out when an alpaca has coughing, exercise intolerance, or unexplained weight loss. Because respiratory signs can also be caused by pneumonia, heart disease, dental disease with aspiration, or even tumors, your vet will usually look at the whole picture before deciding on treatment.

Lungworm infection starts when an alpaca eats infective larvae while grazing. After entering the body, the parasites migrate and mature in the respiratory tract. Adult worms in the lungs produce eggs or larvae that are coughed up, swallowed, and then passed in the feces, which helps continue the life cycle on pasture.

Pasture contamination, close stocking density, and exposure to infected small ruminants can all increase risk. Sheep and goats are well-known hosts for Dictyocaulus filaria, so mixed-species grazing or shared pasture can matter. Wet conditions may also help larvae survive longer in the environment.

Not every coughing alpaca has lungworm. Respiratory disease in camelids can also come from bacterial pneumonia, viral disease, inhaled irritants, tooth root problems, aspiration, or less common conditions such as masses in the chest. That is why your vet may recommend testing before assuming parasites are the only cause.

Diagnosis usually starts with a hands-on exam and a careful history. Your vet will want to know when the cough started, whether weight loss is present, what deworming products have been used, whether the alpaca shares pasture with sheep or goats, and whether other herd mates are coughing.

A fresh fecal Baermann test is one of the most useful tools because it is designed to detect live lungworm larvae rather than standard parasite eggs. A routine fecal egg count may still be helpful for other parasites, but it can miss lungworm. Even so, a negative Baermann does not completely rule lungworm out, especially if shedding is low or intermittent.

If signs are moderate to severe, your vet may also recommend bloodwork, chest ultrasound or radiographs, and sometimes treatment for secondary bacterial pneumonia or airway inflammation. In herd situations, testing more than one symptomatic alpaca can improve the odds of finding the problem. Diagnosis is often a combination of history, exam findings, fecal testing, and response to treatment.

Prevention starts with herd-level parasite control, not routine deworming on autopilot. Work with your vet to build a plan based on your region, stocking density, pasture conditions, and whether your alpacas share space with sheep or goats. Strategic fecal monitoring helps identify when parasites are actually a problem and may reduce unnecessary dewormer use.

Good pasture hygiene matters. Avoid overcrowding, remove manure when practical, rotate grazing areas, and reduce exposure to wet, contaminated ground. If your alpacas co-graze with small ruminants, ask your vet whether that setup changes parasite risk on your property.

Watch body condition and breathing closely, especially in younger or stressed animals. Early coughing, slower weight gain, or reduced stamina can be the first clues. Prompt testing of symptomatic alpacas can protect the individual animal and help prevent a larger herd issue.