Dog leptospirosis is an acute infectious disease caused by bacteria from the genus Leptospira (Leptospira). This disease is characterized by severe damage to the capillaries, and often obvious damage to the kidneys and liver, muscle tissue, which is accompanied by intoxication and constant fever.
Which dogs are at risk?
The bacterium Leptospira, represented by six different serotypes. The causative agent of Leptospira is able to infect dogs of all breeds, regardless of their age. In veterinary practice today, most cases of infection of animals, as a rule, occur only in serotypes L. Icterohaemorrhagiae and L. Canicolau.
In the environment, a marked activity of leptospira up to 220 days in lake and river waters, as well as contaminated reservoirs with standing water, is noted. At the same time, the average life expectancy of the bacterial form in moist soil can vary even within 79-280 days. The causative agent of acute infectious disease is resistant to disinfectants, with the exception of special preparations of the first group.
The main carriers of pathogenic bacteria and the sources of their release into the environment include sick and infected animals. All infected individuals are characterized by quite active elimination of bacteria with breast milk, as well as natural feces, excretions from the lungs and genitals.
The main lifelong reservoirs of such bacteria or virus carriers are represented by small rodents, which include rats, groundhogs and ground squirrels, wild mice and voles. The most active outbreaks of leptospirosis in dogs, as a rule, occur exclusively in the summer and autumn periods, when Leptospira feels as comfortable as possible.
Leptospirosis is especially dangerous for the youngest individuals, as well as puppies, due to the incompletely formed immunity in such animals. At risk are also breeds with a rather loose type of constitution, including boxers, French and English bulldogs, Cane Corso, Bullmastiffs, Shar-Pei, Bloodhounds and Basset Hounds.
In any case, leptospirosis of any form is difficult to treat, therefore, in the absence of proper treatment, a fatal outcome is often noted. A favorable prognosis in infected animals is possible only with timely diagnosis, as well as the correct choice of an effective treatment regimen.
After about a week, a dog infected with leptospirosis begins to be released into the external environment, but the duration of this process directly depends on the species characteristics of the leptospira, the resistance of the animal organism, the form and stage of the disease, and viral virulence.
Symptoms of leptospirosis in dogs
The ingestion of the causative agent of leptospirosis in the animal's body provokes the appearance of signs of damage to the circulatory system, malfunctions in the gastrointestinal tract and respiratory system. Against the background of general intoxication of the body, the symptoms of hepatic and renal failure are noted, and the entire central nervous system and heart muscle are disrupted.
The most obvious symptoms of leptospirosis in dogs include an increase in body temperature, often reaching 40-41aboutC. An infected animal will usually experience single or multiple vomiting and diarrhea. In addition to lethargy, general weakness, loss of appetite and complete or partial refusal of food, urination disorders are often observed. Blood appears in the stool and urine.
Examination of the animal reveals the presence of severe soreness in the abdominal cavity, but the manifestations of the disease largely depend on the characteristics of the form of leptospirosis.
Forms of Leptospirosis
In the first phase of infection, leptospira penetrates into the body, their introduction into the blood, liver, spleen, as well as the kidneys and adrenal glands, where there is an increased reproduction of bacteria. A generalized infection is accompanied by repeated leptospiremia, followed by the entry of bacteria into the liver and kidneys, adrenal glands and meninges. At the initial stage of the disease, parasitism on the surface of the cells is noted.
The toxinemia phase is manifested in animals with a clear defeat of the capillary endothelium, as well as an increase in their permeability with the occurrence of severe hemorrhagic syndrome and damage to the liver, kidneys and adrenal glands. After the period of the height of the disease, a phase sets in, characterized by the formation of an unsterile stage of immunity with the appearance of antibodies in the dog’s blood, as well as the clinical extinction of the process.
The final phase is characterized by the formation of a sterile stage of immunity, including humoral, local organ and tissue immunity, after which the dog comes to clinical recovery.
The most characteristic clinical manifestations of leptospirosis of this form are represented by yellowness of the mucous membranes of the nasal and oral cavities, as well as the genitals and conjunctiva. Yellowing is noted on the skin and the inner surface of the ears. An animal infected with this form is characterized by a depressed state and refusal to eat, as well as the presence of a dyspeptic syndrome, including anorexia, severe vomiting and diarrhea.
The blood picture of a sick dog is characterized by an increased concentration of bilirubin. Along with hemorrhagic, with an icteric form, signs of renal and hepatic insufficiency, disturbances in the functioning of the stomach and intestinal tract, and liver dysfunction are diagnosed. The presence of severe pain during palpation of the abdominal region of the animal is noted. Strong, sometimes even irreversible lesions of the stomach and intestines are not ruled out.
The cause of death of a dog affected by the icteric form is the appearance of toxic infectious shock, severe general intoxication and dehydration of the body, and keratitis and conjunctivitis can be diagnosed in recovered individuals.
The hemorrhagic (anicteric) form of leptospirosis is diagnosed in most cases in age-related animals and weakened dogs. Most often, the disease proceeds in a subacute and acute form, in which the development of clinical symptoms takes 2-7 days, and animal mortality rates reach 55-65%. The subacute form of leptospirosis is characterized by a slow development of clinical manifestations and their lesser severity. The duration of the disease can vary between 10-23 days. With this form, complications of secondary diseases and infections are noted, and the mortality rate is approximately 35-55%.
In some dogs, the transition of the subacute and acute stage of leptospirosis to a chronic form is observed, accompanied by a weak severity of the clinical picture. The body temperature in this case may have a slight increase or is strictly within the normal range. Malfunctions in the functioning of the organs of the gastrointestinal tract and central nervous system are diagnosed, and a decrease in protective mechanisms and forces is also noted. In the chronic form of leptospirosis, a undulating course of the disease is observed in the remitting variant with varying degrees of intensity of symptoms and the severity of the clinical picture.
The first symptoms of leptospirosis appear in the dog about 24 hours after infection. The onset of the disease is accompanied by short-term hyperthermia with a rather sharp increase in body temperature to indicators 41.0-41.5aboutC. In this case, the animal has a strong thirst, pronounced anemia of the mucous membranes and conjunctiva. A dog infected with this form of leptospirosis has a weak reaction to external stimuli, quickly becomes lethargic and lethargic, completely refuses to eat. After 24-48 hours, the body temperature drops to the level of 37.5-38.0aboutC, a pronounced hemorrhagic syndrome develops with blockage of blood vessels by numerous leptospira exotoxins and subsequent lysis of red blood cells.
A pronounced clinical picture of the disease is accompanied by the appearance of external and internal bleeding with severe bleeding of the mucous membranes and the formation of necrotic foci. In this case, bleeding affects the gastrointestinal tract, as well as other organs and systems of the body. The animal has severe profuse diarrhea with disseminated syndrome and bruising in the area of intramuscular or subcutaneous injection. The dog is tormented by bouts of nausea and debilitating vomiting with blood inclusions. In urine and feces, mucus with blood clots is noticeable. Attacks of diarrhea can be replaced by constipation.
With the hemorrhagic form of an acute infectious disease in the urine, a very high protein content is noted. An animal with leptospirosis is sedentary and apathetic, and hemorrhagic lesions of the meninges in a dog are most often accompanied by severe nervous disorders and severe disturbances in the functioning of central nervous system organs. During the diagnosis, during the palpation of the abdomen, as well as the kidneys and liver, the dog experiences very severe pain attacks, so it behaves extremely restlessly.
The hemorrhagic form of leptospirosis is characterized by dehydration, intoxication, the acute stage of hemorrhagic enteritis, acute renal and / or liver failure, oliguria, and frequent clonic seizures are noted.
Diagnosis and treatment
To make the most accurate diagnosis and the subsequent selection of the optimal treatment regimen, the veterinarian, in addition to collecting a general history of the dog, will need to conduct a number of basic standard diagnostic measures. In this case, the urine and blood of the animal are mandatory examined, and in some cases, the excretion of the genitals of the dog is subject to investigation.
Urine is examined under a microscope, and biological material is also sown on specialized laboratory media, which makes it possible to determine the type of living pathogens as accurately as possible. It is important to remember that the level of information content of such an analysis directly depends on whether antibiotic therapy has been given to a sick animal. The secretions obtained from the genitals of the dog are also examined microscopically.
A blood test to detect the presence of antibodies to the Leptospira pathogen is performed a couple of times, with a standard weekly interval. If the animal is sick with leptospirosis, then in its blood the total number of antibodies can be increased several tens of times. If necessary, a veterinarian prescribes a number of other measures and studies aimed at confirming the diagnosis and determining the stage of development of the disease.
The complex treatment of leptospirosis is divided into four main stages, including the effective destruction of the causative agent of Leptospira disease, the stimulation of cardiovascular activity, as well as the elimination of toxins with the subsequent restoration of the functioning of all organs and systems. It should be noted that the basis of successful therapy is represented by the fight against the pathogen. Additional treatment steps may vary depending on the general condition of the dog.
The antileptospirosis gamma globulin has a high therapeutic effect, which is supplemented by antibacterial therapy with the appointment of time-tested drugs "Penicillin", "Tetracycline" and aminoglycosides. Detoxification therapy should be prescribed with mandatory control of the volume of daily diuresis. The symptomatic therapy of leptospirosis includes modern hemostatic agents, as well as the correction of acid-base balance.
After treatment, the animal forms a stable immunity, which lasts for several years. When leptospira is affected by renal tissue, many dogs remain active carriers of disease pathogens for a long time. To make sure that the pet is no longer a carrier of bacteria, you must pass a urine test for laboratory testing several weeks after recovery.
Regarding forecasts, the problem of leptospirosis is rather complicated, therefore veterinarians give them with great care. If the treatment regimen for an infectious disease was prescribed correctly and on time, then in about 50% of cases the dog recovers in the second or third week. With serious damage to vital organs, including the kidneys and liver, the likelihood of death is significantly increased.
An autopsy is required for the dead dog, which allows you to examine fluids taken from the chest and peritoneum of the animal, as well as tissue of the kidneys and liver to identify the pathogen form.
Leptospirosis is a very dangerous infectious disease for animals, affecting dogs, regardless of their breed or age. To prevent infection with leptospirosis, prophylactic vaccination is carried out. For this purpose, mono - and multivaccines are used. Associated vaccines of foreign and domestic production, which have very high efficiency against the serotypes of Leptospira Canicola, Icterohaemorrhagiae, give good results.
Veterinarians recommend using Biovak-L, Leptodog and Multikan-6 as a preventive measure. The dosage of the drug to be administered must be selected by the veterinarian, taking into account the instructions on the package and the body weight of the animal. Puppies are first vaccinated against leptospirosis at the age of eight or ten weeks. In this case, re-vaccination is carried out after 21 days. For adult animals, as well as age-old dogs with unknown immune status, in conditions of adverse epizootic conditions, active-passive vaccination, hyperimmune-type serums, are used.
When planning a trip with a dog to regions unfavorable for leptospirosis, prophylactic vaccination is carried out a month before the trip. Breeders and dog breeders should pay special attention to the conditions of the animals, as well as the diet of pets. It is strongly not recommended to neglect basic hygiene and preventive measures. It is important to pay attention to the standard strengthening of the immune forces of the canine organism and adhere to the vaccination schedule established by the veterinarian and timely treatment of the animal against ectoparasites.
The owner of the dog needs to monitor the cleanliness of the aviary, as well as the sleeping place of the pet, using modern drugs and special disinfectants that are approved for use for this purpose.
The consequences of leptospirosis
If a dog infected with an acute infectious disease survives, then later on it quite often there are a number of serious complications, including liver and kidney dysfunction, malfunctions of the digestive system. Moreover, the recovery period, which is necessary for organs and systems, takes from one to three months. At this stage, a special course therapy is carried out, involving the use of enzyme and modern hepaprotective drugs.
In order to avoid serious complications, drugs are prescribed that normalize the work of the organs of the gastrointestinal tract, as well as a specially developed therapeutic diet, supplemented with vitamin B drugs. Hepatoprotectors such as Essential, Galsten and Karsil help restore liver function. The appointment of ascorbic acid and rutin to the animal gives a very good result in strengthening the vascular system. To strengthen the weak heart muscle, the drugs "Thiotriazolin", "Riboxin", as well as other types of pacemakers are used. Often, at the recovery stage, homeopathy is prescribed.
Danger to humans
Leptospirosis belongs to the category of contagious, zooanthroponous very dangerous infections that cause hemorrhagic inflammation of the liver, digestive organs and central nervous system. Such a disease is easily transmitted from an infected animal to a person. To confirm the diagnosis, an epidemiological history is collected, antibodies in paired sera are detected, and blood is also taken to perform culture on culture media, urine is examined. Specific RNA or DNA is detected using RT-PCR or PCR.
The mechanism of transmission of leptospirosis is exclusively contact. The causative agent enters the human body through damaged skin and mucous membranes, in the process of swimming in dirty water bodies, characterized by stagnant water. Well-known cases of nutritional infection as a result of drinking raw water from unverified natural sources, meat and milk. The causative agent is not transmitted to humans, since the disease is a typical zoonosis.
The clinical manifestations of leptospirosis in humans depend on the form of the disease and include fever, injection and icteric sclera, enlargement of the liver, the appearance of intense muscle pain and tachycardia, the occurrence of oliguria, and then anuria. In very complex cases, infectious myocarditis and hemorrhagic syndrome develop, as well as clear meningeal symptoms.
Complications caused by leptospirosis are most often present in people with acute hepatic insufficiency as a dangerous hepatic coma, acute form of renal failure and bleeding, damage to the membranes of the eyes and myocarditis, paralysis and paresis, as well as toxic toxic shock.