Adult pet | Florence, FI | Il Poggetto Veterinary Clinic

Leishmaniasis and filariosis

Leishmaniasis

Leishmaniasis is unfortunately quite prevalent in our city and its surroundings, as well as in many other areas of Italy.

Although it is a tropical disease affecting humans, in our region it primarily affects dogs.

Transmission occurs through the bite of a phlebotomine, a small mosquito commonly known in our area as a ‘sandfly’.

When one of these insects bites a dog (most often on the nose and other areas with little fur), it first injects an anticoagulant saliva containing the larval forms of Leishmania before beginning to suck the blood. The dog does not necessarily become ill immediately. In fact, it can sometimes take several months for the disease to start showing symptoms.

Generally, two forms of leishmaniasis are recognised: cutaneous and renal.

Cutaneous form
In the case of the cutaneous form, the symptoms can be varied: weight loss, reduction of muscle mass in the head, generalised enlargement of the lymph nodes, thinning of the fur (especially on the eyelids and back), appearance of large flakes of dandruff, nosebleeds, onychogryphosis (excessive nail growth), skin sores with poor healing tendency, and a cracked nose.
However, these symptoms may not all appear together or may not appear at all.
Renal form
The renal form is much more serious, as it leads to acute renal failure, typically characterised by a sudden increase in thirst, loss of appetite, vomiting, sometimes an increase in urine production, and at other times a drastic decrease.
Rapid dehydration, hypothermia, and uremic coma are the final stages of this form of leishmaniasis.
Diagnosis and advice
In practice, diagnosis is only made through laboratory tests; generally, a blood sample can diagnose the ‘seropositivity’ of a dog after it has been bitten, even if it is still completely asymptomatic.

Although a vaccine is now available (see the next paragraph), it is always advisable to follow some simple guidelines to protect your dogs as much as possible:

Have your dog sleep indoors or in kennels protected by mosquito nets, as sandflies typically bite at night.
Use insect-repellent products on your dog’s fur to reduce the chances of being bitten by mosquitoes.
Have the dog’s blood checked every six months to determine if the dog has been infected.

In the unfortunate event that your pet tests ‘positive’, it is useful to perform a second blood test to assess whether the disease has started to manifest by altering specific blood parameters.

If this is the case, the vet will advise you on whether and what treatments to carry out to effectively manage the condition.

It is also worth noting that while leishmaniasis is a treatable disease, it is rarely completely curable. Nonetheless, many dogs that test positive can lead an almost normal life.

Leishmaniasis vaccine

The first vaccine for leishmaniasis was introduced in 2011. Ongoing studies and research have led to an improved version of the vaccine by 2018, which offers better efficacy and fewer side effects.

The vaccination protocol begins at 6 months of age, with a single initial dose followed by annual booster shots.

The vaccine can be administered to dogs who are:

In good health
Free from intestinal parasites
Over 6 months of age
Negative on the Leishmania screening test

Filariosis

In Italy, filariosis is a disease primarily affecting dogs (rarely affecting cats) and has been known for several years in Northern Italy and the coastal regions of Central Italy. However, it has only recently appeared in our city and surrounding areas.

Along with leishmaniasis, filariosis is one of the most widespread mosquito-borne diseases in dogs.

When a mosquito bites a dog infected with filariosis and ingests its blood, it also takes in some microscopic larvae present in the bloodstream.

After a few days, these larvae are transferred to the mosquito’s salivary glands and can infect new hosts that are bitten by the insect.

After about 3-6 days, the larvae mature in the dog’s dermis where they were injected and start migrating towards the heart and lungs through the blood vessels; they further transform into adults over approximately 35-40 days.

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The adult parasite is a whitish, round-sectioned, slender worm that can grow up to 30 cm long. It resides with other similar worms in the right atrium of the heart, pulmonary veins, and the vena cava, forming 'tangles' that can obstruct normal blood flow within the heart.

Symptoms of filariosis typically include easy fatigue in affected dogs, and in severe cases, signs of heart failure such as dyspnoea, oedema, ascites, and cardiac arrhythmias.

Prevention

Fortunately, there are ways to protect our canine friends from this serious disease.

You can choose between injectable or oral prophylaxis.

The injectable product is administered once at our clinic and provides protection for 12 months.

Oral prophylaxis is administered monthly at home by the owner, and accuracy in administration is crucial for this method.

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In the unfortunate event that a dog contracts filariosis, there are treatments available that can cure the disease completely. However, these treatments are not without risks. Injectable medications used to kill the worms in the heart must be preceded by a proper anticoagulant therapy and followed by at least a month of complete rest to avoid the risk of dead parasite fragments entering the bloodstream and causing potentially fatal thromboembolic events.

For this reason, we strongly recommend prophylaxis.