Leishmaniasis is an infectious animal disease caused by an intracellular parasite. This parasite of the Leishmania genus is carried by mosquitoes. The spread of the disease contribute to both domestic and wild mammals. Leishmaniasis can be visceral or cutaneous.
Etiology
The life cycle of the parasite passes with a change of owners: a vertebrate animal, including humans, and a carrier, a mosquito. There are 2 types of leishmania - flagellate, parasitizing in the bodies of blood-sucking insects, and flagellate - in the cells of the host macrophages.
Leishmaniasis is distributed in animals predominantly endemic. However, most cases are reported in developing countries. In 32 countries, the disease is subject to mandatory registration.
For the first time, leishmaniasis in an animal in Russia was discovered in 1909. The described case was related to the dogs of Transcaucasia. From 2008 to 2010, 52 cases of the occurrence of this disease in dogs were registered in Ukraine.
Epizootology
The disease starts from infected animals or humans. When bloodsucking, insects get amastigotes, which begin active reproduction in his intestines. After 8-10 days, the amastigotes turn into invasive forms, concentrated in the proboscis of the mosquito and the anterior intestines. At the next bite of the carrier, the parasite enters the blood of the vertebral and begins to multiply. In just a day, more than 200 pieces of amostigos can be in one cell. The cells overfilled with parasites are completely destroyed, the amastigotes are captured by neighboring cells, in which the process repeats. Thus, Leishmania appears in the skin, bone marrow, liver, lymph nodes and any other organs.
Incubation period
The clinic is different depending on the form of the disease. The incubation period of visceral leishmaniasis can last up to 10 months, developing gradually.
Leishmaniasis of the skin develops rapidly, its incubation period is extremely short.
Signs
The disease affects animals of any age and gender. In young animals, symptoms are less likely to occur at an early stage, leading to late diagnosis and a higher mortality rate. Some studies prove that animals aged 3-5 years are most prone to leishmaniasis.
Leishmaniasis in animals, a photo of which can be viewed here, follows the classical pattern, affecting all the organs and cells of the animal.
The cutaneous form of leishmaniasis begins with the appearance of nodules at the site of the bite by the carrier. Over time, these nodules flow into ulcers. The areas around the eyes, back of the nose and ears of the animal are most susceptible to primary disease.
In this form, the disease can pass sluggishly, for a year or even longer. The death of an animal at this stage is extremely rare. Visceral leishmaniasis is much more severe: it can be acute or chronic. With any form of fever, there is a general depressed state of the animal, severe weight loss.
Conjunctivitis, anemia develops simultaneously with the remaining symptoms in a sick animal, and digestive upset is often observed. Paralysis or paresis may occur, hemodynamics are significantly impaired. Since the body slowly breaks down under the influence of parasites, allergic or toxic reactions are possible.
With the multiplication of Leishmania, the liver, lymph nodes and spleen increase. The acute form of the disease is more typical of young animals. Usually, death occurs within a few months after the first signs of the disease appear. Cases of recovery rarely occur.
With the visceral form of leishmaniasis, a gradual increase in the weakness of the animal’s body occurs, and fatigue increases. The skin turns pale, appetite decreases. At this stage, by palpation, an enlargement of the spleen can be noticed. A slight increase in temperature occurs. If the temperature has increased significantly, this indicates a peak in the disease. This course of the disease can last up to 3 months.
With the development of the disease, anemia, cachexia can begin. On the mucous membranes there are areas affected by necrosis. Heart disease is possible.
Leishmaniasis in animals in skin form manifests itself within 10-20 days. Initially, a papule appears with a diameter of about 3 cm. After about 2 weeks, you can already observe a necrotic focus surrounded by a roll of infiltrated skin with copious discharge. Not far from the primary leishmanoma, secondary tubercles form, turning into new ulcers. Over time, all ulcers merge into one large focus. With proper and timely treatment, these ulcers heal in a few months, in their place there are significant scars, which are rarely covered with wool again. Tubercles and ulcers are almost painless formations.
Complications
With a sufficiently long course of the disease, the risk of developing nephritis, diathesis, pneumonia, agranulocytosis is high. There is a high probability of the appearance of purulent-necrotic inflammation. With a significant damage to the body, irreversible damage to the organs of vision is possible.
Diagnostics
With leishmaniasis, various studies are carried out to identify the pathogen. So, a general blood test can show an elevated ESR, hypochromic anemia, and a low platelet concentration. Biochemistry will reveal hypergammaglobulinemia. Cutaneous leishmaniasis in animals is diagnosed after the pathogen is isolated from ulcers and tubercles. Visceral leishmania is detected in blood culture. In some cases, a biopsy of various organs is performed.
When epidemiological studies produce a skin test with leishmanin (Montenegro reaction).
Currently, new methods for diagnosing leishmaniasis are being developed, since those that are currently available require significant material costs and take a lot of time.
Ulcers with leishmaniasis are similar to foci with anthrax carbuncle, therefore, for accurate diagnosis, it is preferable to exclude the presence of the causative agent of anthrax.
Forecast
Mild leishmaniasis in an animal sometimes ends in self-healing. With timely diagnosis and proper medical intervention, a favorable end to the disease is also great. In severe cases, with infection of individuals with weak immunity, in the absence of medical assistance, a high probability of death. Leishmaniasis of the skin always leaves scars or scars.
Treatment
Animal leishmaniasis is treated with pentavalent antimony. These are drugs such as "Glucantima", "Solusurmina" or "Neostibozana". With the visceral form of the disease, these drugs are administered intravenously for 7-10 days with a gradual increase in the recommended dose. With insufficient treatment effectiveness, Amphotericin B is connected, which is administered slowly intravenously in combination with a 5% glucose solution.
Cutaneous leishmaniasis in animals at an early stage can be cured by chipping the tubercles with Monomycin and Urotopin. In addition to injections, lotions are made with the same drugs. If ulcers are already formed, use the Miramistin intramuscularly. To speed up the process of healing ulcers, the use of laser therapy is recommended.
Reserve funds for the disease are Pentamidine and Amphotericin B, which are prescribed in cases of parasite resistance to traditional drugs or in case of infection recurrence.
In order to increase the effectiveness of the treatment, recombinant gamma-interferon, developed for the treatment of humans, is added.
In rare cases, the cure requires surgical removal of the spleen.
Despite all the measures taken to get rid of the disease, even after the animal has completely recovered, the causative agent of leishmaniasis from the body may not completely disappear.
Prevention
There is currently no way to vaccinate animals and humans. To protect against phlebotomus bites, it is recommended to use special insecticidal preparations created for use in veterinary medicine.
As a preventive measure for leishmaniasis in the settlements located in the risk zone, the places of mosquito resettlement are eliminated, and premises are disinfected.
When a disease is detected in domestic mammals, its owners are usually given chemoprophylaxis with Pyrimethamine.
If a disease is detected in wild animals, for the purpose of prevention, it is recommended that these individuals be destroyed with the complete elimination of their remains.
Attitude to people
More than 350 million people are currently at risk of infection. The foci of the spread of leishmaniasis are in the vast expanses of Asia and Europe. In various areas, vectors of leishmaniasis are the blood-sucking insects that live there. Cases of visceral leishmaniasis have been reported in Ukraine, North Ossetia, in the steppes of Crimea, the mountains of the Caucasus and some other regions.
The disease is not transmitted directly from the animal to humans, but when infected, the first recommended prophylaxis for people, since the fact of the disease indicates the presence of its carriers.
Effects
Leishmaniasis is a disease to which antibodies are not produced. Accordingly, an animal or a person can get sick both a second time and a third. However, such cases are extremely rare, since it is unlikely that the animal can survive more than two repeated infections.
To prevent recurrence of the disease, drugs recommended for treatment are used every six months. However, such frequent use can lead to the development of resistance and toxic effects by the body.
After the illness, the animal’s body needs long-term rehabilitation, and in case of partial or complete removal of organs by surgery, a diet is necessary.
Leishmaniasis in animals is an extremely dangerous and insidious disease, so people living in unfavorable areas need to carefully monitor their pets so that when the first symptoms (or even just suspicions of an illness) appear, they can provide the necessary help in time.