Leptospirosis is an anthropozoonotic multisystem disease. It affects almost the entire body: liver and kidneys, lungs, spleen, anterior chamber of the eye, retina, cardiac and skeletal muscles, meninges, genitals and pancreas. In addition, it inhibits blood clotting. The development of the disease in dogs does not depend on age, gender or breed. But young individuals are most susceptible to the disease.
Etiology
The causative agent of the disease is the gram-negative spiral-shaped bacterium Leptospira, family Leptospiracea, class Spirochaetaceae. It is susceptible to drying out, pH fluctuations and high temperatures. It dies almost instantly at temperatures above 76o C. But it persists for six months in moist soil, and for a long time in surface waters. Leptospires persist longer in stagnant water than in flowing water.
Who is sick:
- dogs;
- horses;
- cattle;
- MRS;
- wild carnivores;
- rodents and fur-bearing animals;
- domestic as well as wild birds.
Cats rarely get sick.
The infectious disease is also dangerous for humans.
Rodents suffer subclinically. They form the most important reservoir of infection in nature because they are lifelong carriers of leptospirosis. Dogs and rats have become the main reservoir in urban areas, and cows, horses and sheep in agricultural areas. Bacteria enter the environment through nasal discharge, genital discharge, urine, feces and milk.
You can become infected with leptospirosis in three ways:
- Contact - through intact mucous membranes or damaged skin in contact with water, other individuals, their secretions or contaminated soil.
- Nutritional – when drinking from open water, eating rodents, meat of sick animals or contaminated products.
- Transmissible - through insect bites.
There are more than 200 serotypes. Certain animal species are affected by different serotypes of pathogens. For example, pigs are infected with L. Pomona and L. Tarassovi, dogs with L. Canicola, cows with L. Hardjo and L. Pomona, horses with L. Bratislava, and rats with L. Icterohaemorrhagiae and L. Copenhageni. In addition to the main hosts, there are intermediate ones - they may not show clinical signs of the disease, but can be sources of infection.
Who is sick and why
All dogs are susceptible to leptospirosis.
How can a dog become infected with leptospirosis?
Infection can occur through direct contact with sick animals or leptospiron carriers (very often, mouse-like rodents are carriers of the infection).
Contact with wild rodents can lead to leptospirosis. Photo: Adam Levison
Leptospira can live for a long time in the environment, especially in the warm season. For example, they can be stored in fresh water for up to six months. Therefore, you can become infected through leptospira-contaminated care and feeding items, food and water (including when swimming in contaminated bodies of water with stagnant water).
Do not allow your dog to swim in ponds with standing water. Photo: Simon
The infection enters the body through the mucous membranes (most often through the gastrointestinal tract when Leptospira enters with food or water), as well as through the skin if it has the slightest damage, and is then spread by blood throughout the dog’s body.
Risk group
Animals whose immunity is reduced are most susceptible to the disease, especially when kept in crowded conditions.
Hunting dogs are at risk for leptospirosis. Photo: Andrea Pokrzywinski
Also at risk are dogs that are kept in conditions of close access to sources of infection, including hunting dogs.
Carriage
It is worth noting that during any course of the disease, as well as after recovery, viable leptospira are excreted from the body of the infected animal (mainly in the urine).
If the dog has not undergone full antibiotic therapy aimed at destroying the pathogenic bacteria, then the microbial carrier state may persist in the coming years.
Only a sufficient level of immune response protects carrier dogs from the disease becoming acute; if immunity decreases, the disease may return.
Leptospirosis is transmitted to humans
It is very important to remember that many species of animals, as well as humans, are susceptible to leptospirosis. And the types of Leptospira that most often cause disease in dogs also cause leptospirosis in humans.
If you suspect your dog has leptospirosis, you should immediately contact your veterinarian and take safety precautions for yourself. This disease is very contagious, which means it is necessary to be careful when caring for a sick pet and strictly observe the rules of hygiene - personal, dog, as well as regarding its care and feeding items.
Photo: Robert Tadlock
Pay attention to your own well-being and if it worsens or you suspect any disturbances, consult a doctor in order to promptly determine their cause and avoid possible negative consequences.
Pathogenesis
After entering the body, leptospira penetrates the bloodstream and spreads to all organs. Their active reproduction causes an increase in temperature. On days 3-5, lysing antibodies are produced, so the pathogen disappears from the blood. They break down, releasing endotoxin. Under its influence, cells of parenchymal organs and blood are destroyed.
Anemia develops due to a decrease in the number of red blood cells. Free hemoglobin accumulates, from which bilirubin is formed. It does not bind to glucuronic acid, as it should normally, but is adsorbed by tissues, turning them yellow.
At the same time, the filtration capacity of the kidneys is impaired, so red blood cells and hemoglobin are found in the urine. The endothelium of the capillaries of organs is affected and hemorrhages develop. The intoxication phase ends with death or recovery. But even in recovered individuals, leptospira persist and multiply in the convoluted tubules of the kidneys for a long time. Therefore, they pose a danger as a source of infection.
Symptoms of leptospirosis in dogs
The clinical picture of the disease is extensive. Since the disease affects almost the entire body, the following symptoms develop:
- vomit;
- lethargy;
- diarrhea;
- refusal to eat;
- increase or decrease in temperature;
- abdominal and muscle pain;
- oliguria or anuria;
- dyspnea or tachypnea;
- weight loss.
Such symptoms should alert the owner and cause immediate contact with a veterinarian. After all, a pet in this condition needs emergency care and intensive care.
There are two main forms of leptospirosis:
- Hemorrhagic or anicteric – more often recorded among adults. Spontaneous onset is characterized by short-term hyperthermia, refusal of food, increased thirst, redness of the mucous membranes of the nose, mouth and conjunctiva. After two or three days, a hemorrhagic syndrome forms: external and internal hemorrhages, bleeding of mucous membranes. Clinical symptoms can manifest rapidly: convulsions occur with subsequent death.
- Jaundice - usually affects puppies under one to two years of age. Often with this form, a short-term increase in temperature, vomiting or diarrhea with blood, and gastroenteritis are also observed. But the main feature is liver damage and disruption of its functionality due to the proliferation of Leptospira in it. A bright yellow color of the skin and mucous membranes is observed. Acute renal failure develops, the liver and spleen enlarge. Due to systemic damage to these organs, toxic shock begins, resulting in death.
These forms, in turn, have several currents. For example, in hemorrhagic they distinguish:
- Acute – lasts 1-5 days. Mortality – 60-80%.
- Subacute – symptoms develop slowly and are mild. Duration – from 10 to 15 days. When adding secondary infections, this period can increase to 20 days. Mortality – 30-50%.
- Chronic – the period of leptospirosis after recovery.
In the acute course of the icteric form, mortality is 40-60%, and the duration of the disease is 1-5 days. The subacute course can last up to two weeks, but the prognosis is also unfavorable.
The owner will not be able to accurately recognize the symptoms of leptospirosis in a dog and, of course, he will not know how to treat correctly. If your pet is sick, develops the symptoms described above, and has also had contact with a potential source of infection, you must urgently go to the clinic and undergo an examination to rule out the disease in question.
Methods of infection
Animals with low immunity are vulnerable to the disease: puppies under 6 months of age, elderly dogs and pets with chronic pathologies. You can become infected with bacteria during:
- Swimming in stagnant ponds
. Puddles and creeks are the usual habitat of Leptospira. In such an environment, microorganisms live up to 200 days. They are not afraid of the absence of a host, so the only real threat is frost, which prevents active reproduction.
- Crowded content
. The small area of premises in nurseries increases the risk of epidemics. If at least one of the animals is infected, all the inhabitants will be at risk.
- Pregnancy and lactation
. In these cases, microorganisms pose a danger not only to the infected mother, but also to her offspring.
- Drinking contaminated water or food
. A common cause of infection is meat served without heat treatment.
- Contact with vector animals
. The disease is transmitted by other sick dogs, small rodents and blood-sucking insects. Also dangerous are arctic foxes, foxes, martens or other predators that have eaten an infected mouse or rat.
Regardless of the method of infection, the bacterium penetrates either through damaged skin and mucous membranes, or through the mouth. The carrier becomes dangerous to others during the incubation period.
Diagnosis of leptospirosis in dogs
The diagnosis is made comprehensively. The doctor conducts all routine tests: general and biochemical blood tests, general urinalysis, X-ray of the lungs, ultrasound, PCR and ELISA.
It is advisable for all patients with an acute stage to undergo radiography to prevent severe complications. For example, pulmonary hemorrhages. An ultrasound will provide more data about acute kidney damage: an increase in size or accumulation of fluid near them.
The “gold standard” is PMA (microagglutination reaction). This is the most widely used test. It is carried out 3-5 days after the onset of the disease, when antibodies appear in the blood.
The results of laboratory analysis are affected by recent use of antibiotics - they reduce titers. And also vaccination. Blood serum can be examined in PMA 2 months after vaccination. Otherwise, the test will show a false positive result.
For earlier diagnosis of leptospirosis in a dog, PCR is performed - until antibodies are formed. This sensitive and specific method detects the DNA of the pathogen.
Only after all tests for leptospirosis in a dog have been carried out, can the doctor make the correct diagnosis and prescribe treatment. In no case should you treat yourself, because without properly provided assistance, the disease will end in death.
Treatment of leptospirosis in dogs
The basis of the therapeutic regimen around the world is doxycycline and streptomycin. One of these drugs is used for a long time - 14 days to completely eliminate Leptospira in the renal tubules.
Patients with disturbances in the digestive system (vomiting/diarrhea) are prescribed intravenous therapy. The standard initiation of this treatment consists of administering ampicillin or amoxicillin every 6 to 8 hours.
In general, the scheme consists of:
- infusion therapy;
- diuresis control;
- pain relief;
- correction of acid-base status and electrolyte disturbances;
- transfusion of plasma or whole blood in case of heavy blood loss or the development of coagulopathy.
All this is supportive treatment for a dog with leptospirosis, which continues until the animal’s parameters normalize.
Prevention and use of vaccines against leptospirosis in dogs
Owners should always pay special attention to the prevention of infectious diseases. In Russia there is a large selection of polyvalent vaccines against animal leptospirosis, protecting the body from the effects of different strains.
For example, vaccinations are:
- Bivalent (Icterohaemorrhagiae + Canicola): Eurican Lepto, Nobivak Lepto-2, Vanguard-7, Duramon DAPPi & LC.
- Quadrivalent (Canicola + Icterohaemorrhagiae + Gryppotyphosa + Pomona): Nobivak Lepto-4.
- Trivalent (Canicola + Icterohaemorrhagiae + Gryppotyphosa). These drugs are common in Europe.
Doctors recommend giving quadrivalent leptospirosis vaccines to dogs that live in agricultural areas or are used for hunting. And it is advisable to vaccinate in the spring before the start of the most dangerous period for infection - summer.
Dogs are vaccinated against leptospirosis at three to four months of age, then 1 per year every 12 months.
Prevention measures
One of the risk factors for infection for dogs is contact with sick animals and their natural secretions. Therefore, it is important to isolate infected dogs and follow the rules of hygiene, use antiseptics when working with them, so as not to transmit the pathogen to other animals.
Vaccination is critical to preventing the disease in dogs. In addition to this, the following preventive measures are recommended:
- disinfection of premises, outdoor areas, household items that were used by infected dogs;
- It is prohibited to import sick and recovered dogs into kennels;
- Animal slaughter products that have not been tested by a veterinarian should not be fed to dogs;
- do not allow animals that have not been vaccinated against leptospirosis to participate in exhibitions and events;
- do not walk dogs on the street that have not been vaccinated against leptospirosis and other infectious diseases within the prescribed period;
- do not allow dogs to swim in stagnant bodies of water, including those located within the city;
- It is recommended to carry out mating only if both individuals are vaccinated against leptospirosis and other infectious diseases within the prescribed period;
- ensure systematic extermination of rodents in residential premises and local areas;
- dogs should defecate away from standing water, where other animals and people, especially children, will not have access;
- a sick dog should be isolated both from other animals and from random unaware people;
- When working with infected animals, their waste (urine, feces) and contaminated household items (bowls, trays, etc.), latex gloves, masks and safety glasses should be used (when washing contaminated areas with hoses).
The best way to protect against leptospirosis is vaccination! The disease is easier to prevent than to treat.
About the possibility of transmission to humans
Yes, a person can become infected from their pet. But infection between people occurs in rare cases.
Sick dogs are recommended to be left for treatment in a hospital. But, if this is not possible, then you should limit contact with other people as much as possible. Risk groups include children, pregnant women, the elderly and people with weakened immune systems.
Hands should be washed thoroughly before and after contact. To carry out manipulations, you should wear gloves, a mask, eye protection and a disposable gown. All biological fluids from the patient are disposed of as medical waste, and the room is regularly disinfected.
All this is quite serious, so if you notice alarming symptoms in your pet, immediately contact a veterinary clinic. Remember that the speed of treatment depends not only on the outcome of your pet’s illness, but also on the health of the people around him. You can make an appointment with a specialist via chat or call. The specialists of the AMVet veterinary clinic will provide emergency care, make a diagnosis, prescribe adequate treatment for your dog for leptospirosis, and answer all your questions.
Treatment of dogs
It is important to remember that the sooner the animal is shown to the veterinarian, the greater the chance of recovery. Be attentive to your pets. Treatment of leptospirosis is carried out comprehensively in several stages:
- To make an accurate diagnosis, they resort to laboratory tests, for which urine and blood are examined;
- Initially, the goal of treatment is to destroy the pathogen;
- Next, the doctor takes measures aimed at maintaining and restoring the functioning of the cardiovascular system;
- Intoxication is eliminated and diarrhea stops;
- The functioning of the kidneys, liver, and stomach is restored.
When treating, the most important task is always the destruction of leptospira, so all subsequent stages can be postponed and their order changed. In addition to taking medications and medications, the dog is prescribed a diet that should exclude large amounts of proteins and fats. During recovery, it is important to drink plenty of fluids and eat small meals.
Preventive actions
Vaccination is used to prevent leptospirosis. It is carried out regardless of the age and breed of the dog. Mono- and polyvaccines are used, as well as associated vaccines of domestic and foreign production. They are designed to effectively protect against pathogenic bacteria. The prescribed dosage depends on the dog’s weight and is indicated on the vaccine packaging. Vaccination is best done at a veterinary clinic.
The first vaccination is given to puppies at 9 weeks of age, and the second is repeated 3 weeks later.
Adults are prescribed hyperimmune serums as a preventive measure. It is important to carry out treatment against ectoparasites in a timely manner and keep your pet’s sleeping area perfectly clean. The same goes for where you eat.
