Humpback whale pneumonia
Humpback whale pneumonia is an infection or inflammation of the lungs observed in this large migratory cetacean. It affects the respiratory system, already heavily stressed by the lifestyle of the animal which must regularly come to the sur...
What is it?
Humpback whale pneumonia is an infection or inflammation of the lungs observed in this large migratory cetacean. It affects the respiratory system, already heavily stressed by the lifestyle of the animal which must regularly come to the surface to breathe. This condition is mainly documented during strandings or necropsies, because it is very difficult to observe a sick whale in the open sea. It remains a recognized cause of mortality among cetaceans, particularly among young individuals and weakened animals.
Key point
Potentially fatal condition, particularly in young whales and during strandings.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
The signs are difficult to spot at sea because the whale spends most of its time underwater.
However, we can observe an abnormal breath (exhalation at the surface), noisier, weaker or irregular.
The animal may appear tired, swim more slowly, stay on the surface longer, or space its dives unusually.
Visible weight loss, with a hollower silhouette at the back and behind the head, is sometimes noted in chronically ill animals.
Some stranded individuals have labored breathing or visible secretions at the blowhole.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
Several agents may be involved: opportunistic bacteria naturally present in the marine environment or the respiratory tract, respiratory viruses specific to cetaceans, or more rarely fungi.
The infection can set in on lungs already weakened by stress, a wound, pulmonary parasitosis or weakened immunity.
In young calves, an insufficient transfer of immune defenses or early separation from the mother can promote the disease.
Young individuals, weakened animals, injured animals or victims of collision with a vessel or entanglement in fishing gear are more vulnerable.
Stress linked to noise pollution, chemical pollution of the oceans or a reduction in the availability of prey can weaken natural defenses.
Migration periods, which are particularly demanding in terms of energy, are times of increased risk.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The diagnosis is very rarely made on an animal living at sea.
It is most often based on the observation of abnormal respiratory behavior by teams specialized in marine biology, supplemented if possible by remote samples (biopsy, breath analysis) as part of scientific programs.
In a stranded animal, a complete clinical examination, a blood test, chest imaging and especially the examination of the lungs during a possible necropsy make it possible to confirm pneumonia and identify the causative agent.
Treatment
No curative treatment is possible for a whale at sea.
In the event of failure, specialized veterinary treatment can be attempted with appropriate antibiotics or antifungals, general support and fluid therapy, depending on the means available and the condition of the animal.
The decision to treat always depends on the advice of a team specialized in marine mammals.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
There is no individual prevention applicable as with domestic animals.
Prevention mainly involves protecting the marine environment: reducing pollution, limiting acoustic disturbance, preserving feeding areas and managing maritime traffic to limit collisions and injuries.
Health monitoring of populations by marine conservation organizations makes it possible to better understand and limit risk factors at the population level.
Possible complications
Uncontrolled pneumonia can progress to severe respiratory failure, general exhaustion and death.
It can also be associated with other conditions (parasitic, septicemia) which worsen the prognosis.
In calves, it can seriously compromise growth and survival.
When to see a veterinarian
Observation of an adult whale or a stranded calf, even alive, must be reported immediately to the competent authorities or stranding networks.
Abnormally loud, weak or irregular breathing observed in an animal in distress near the coast.
Isolated whale, very emaciated or swimming abnormally slow and disoriented.
Presence of abnormal secretions at the vent in an animal accessible for observation.
Prognosis
The prognosis is poor in a wild animal, because treatment options are very limited at sea.
In stranded animals treated quickly, the prognosis depends on the severity of the lung damage and the general condition at the time of discovery.
Chronic forms and late strandings are associated with an unfavorable prognosis.
Frequently asked questions
Can we treat a sick whale in the open sea?
No, no treatment is possible on an animal free at sea. Only cases of stranding allow possible specialized veterinary treatment.
How do you know if a whale has pneumonia?
The definitive diagnosis is almost always obtained after a stranding, during a veterinary examination or a necropsy. At sea, only indirect signs such as abnormal breathing can alert specialized observers.
Can whale pneumonia be transmitted to humans?
No, there is no evidence of transmission of this disease from whales to humans.
What should I do if I see a stranded or distressed whale near the coast?
You must immediately contact local authorities or a network specializing in marine mammal strandings, without attempting to handle the animal yourself.
References
WOAH — Organisation mondiale de la santé animale (ex-OIE)
FAO — Organisation des Nations unies pour l'alimentation et l'agriculture
Content reviewed by the TunisieVet editorial team · Updated 24 September 2026
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