LeptospirosisFeline/Canine

Clinical Management

Navies 2011

What causes Leptospirosis?

• Leptospirosis is caused by a gram negative, spirochete bacteria.

Etiology• Leptospirosis is a disease of

worldwide significance that infects both animals and humans.

• Leptospirosis, a contagious disease affecting both animals and humans. Leptospirosis is spread by infection with a bacterial pathogen called Leptospira. This may result in chronic liver and kidney disease and fatality in dogs.

• ZOONOTIC!!!

Leptospirosis History• First described by Adolf Weil in 1886 when he

reported an "acute infectious disease with enlargement of spleen, jaundice and nephritis".

• Leptospira was first observed in 1907 from a post mortem renal tissue slice. In 1908, Inada and Ito first identified it as the causative organism and in 1916 noted its presence in rats.

Leptospirosis (Leptospira interrogans sensu lato)

• Scientific name of the infecting organism is Leptospira interrogans sensu lato. Within this species there are many different strains (serovars). Of these different strains there are eight that are of importance for dogs and cats.

But, who can become diagnosed with Leptospirosis?

• These different strains produce different levels and types of disease depending on the animals they infect. While cats can be infected, they rarely show signs of disease.

Signalment

• The disease is much more of a problem in dogs, people, and livestock. Infection affects multiple organ systems (most to least): kidney, liver, gastrointestinal, hemopoietic (blood & clotting factors), respiratory, and brain.

Leptospira Serovars

Primary Host Dog Cat HumanOther

Domestic Animals

Wild Animals

Rat, pig, horse + _ + Cow, horse Mouse, raccoon, opossum, vole, fox, skunk

Autumnalis Mouse + _ + Cow Rat, raccoon, opossum

Ictero-haemorrhagiae

Rat + + + Cow, horse, pig Mouse, raccoon, opossum, hedgehog, fox, woodchuck, ape, muskrat, skunk, civet

Cow, pig, skunk, opossum

+ + + Horse, sheep, goat, rabbit

Mouse, raccoon, hedgehog, wolf, fox, woodchuck, deer

Canicola Dog + + + Cow, horse, pig Rat, raccoon, hedgehog, armadillo, mongoose, skunk

Bataviae Dog, rat, mouse + + + Cow Hedgehog, armadillo, vole, shrew,

Hardjo Cow + - + Pig, horse, sheep Wild bovidae

Grippotyphosa Vole, raccoon, skunk, opossum

+ + + Cow, pig, sheep, goat, rabbit, gerbil

Mouse, rat, fox, squirrel, bobcat, shrew, hedgehog, muskrat, weasel

Prevention?

• The current canine vaccines protect against the serovars canicola and icterohaemorrhagiae. These two serovars have been decreasing in total number of infections, but unfortunately, other serovars that infect dogs such as grippotyphosa, pomona, and bratislava have increased.

Signalment

• Young-adult, large-breed, outdoor dogs; however, small dogs in urban areas can also contract the disease.

Transmission

• It is transmitted by many animals such as rats, skunks, opossums, raccoons, foxes, etc. It is spread through contact with contaminated soil or water from waste products of an infected animal. The disease can be contracted by:– ingesting contaminated food or water– through broken skin, and mucous

membrane (eyes, nose, sinuses, mouth) – coming in contact with contaminated soil or

water

Transmission

• Leptospirosis is transmitted between animals through contact with infected urine which can get into water and soil and can survive there for weeks to months, venereal and placental transfer, bite wounds, digestion of infected tissue. Crowding in a kennel can also increase the spread of the infection.

Transmission• Indirect transmission occurs through

exposure of susceptible animals to contaminated water sources, food, or even bedding. A suitable habitat for Leptospira is slow or stagnant water, resulting in outbreak during periods of flooding.

Transmission

• In dry areas, infections are more common around water sources. Freezing greatly reduces the chance of the organism surviving in the environment, which is why infections are most common in summer and fall and why infections are more prevalent in temperate areas.

Transmission

• It is not spread from person to person, except in vary rare cases when it is transmitted through breast milk or from a mother to her unborn child. The bacteria can enter through skin or mucous membranes, especially through a cut or scratch.

• http://www.youtube.com/watch?v=7x20O_tZXBc

Risk Factors when considering Leptospirosis

• Occupational exposure- farmers, ranchers, slaughterhouse workers, trappers,

• Veterinarians, loggers, sewer workers, rice field workers, and military personnel.

• Recreational activities- fresh water swimming, canoeing, kayaking, and trail biking in warm areas.

• Household Exposure- petting dogs, domesticated livestock, infected rodents.

Clinical Signs– the incubation period varies

between 3 and 20 days, some dogs & cats may not show clinical signs.

Primary:• -Shivering• - Muscle Tenderness• - Vomiting• - Diarrhea• - Polyuria• - Polydipsia• - Anorexia

Secondary:• - Dehydration• - Jaundice• - Coagulopathy ( inability to stop bleeding)• - Dyspnea

Human SymptomsSymptoms can take 2 -

26 days (average 10 days) to develop, and may include:

• Dry cough• Fever• Headache• Muscle pain• Nausea, vomiting,

and diarrhea• Shaking chills

Less common symptoms include:•Abdominal pain•Abnormal lung sounds•Bone pain•Conjunctivitis •Enlarged lymph glands•Enlarged spleen or liver•Joint aches•Muscle rigidity•Muscle tenderness•Skin rash•Sore throat

Diagnostics

• Complete blood cell count– Leukocytosis– Thrombocytopenia

• Serum chemistry– Increased blood urea nitrogen (BUN)– Creatinine– Increased ALT– Bilirubinuria

• Serology– Serology is the most useful and frequently

used diagnostic test for dogs.

Diagnostics?• - MAT (microagglutination test) will present

with clinical signs of disease prior to the development of antibodies measurable by MAT

• - ELISA (enzyme linked immunosorbent assay)• - PCR (polymerase chain reaction) will be

positive on blood very early in infection usually prior to seroconversion. Urine will become positive 7–14 days after infection at which time leptospires may or may not be detected in the blood.

• - Serologic testing is the most commonly used method for diagnosis of leptospirosis. Negative serologic test results may occur in the early phase of infection. Dogs suspected of being infected but who test negative should be re-tested in two-to-three weeks.

Case

• In July 1998, athletes from 44 states and seven countries participated in triathlons in Springfield,Ill.The Illinois Department of Health, the U.S. Department of Agriculture, and the Centers for Disease Control investigated an outbreak of acute febrile illness in which 110 of 1194 (9.2%) participants experienced chills, headache, myalgia, diarrhea, eye pain or conjunctivitis. The investigation indicated that Leptospira bacteria caused illness in some of the athletes exposed to Lake Springfield, where the Illinois triathlon was held.

Case• In 1988, a 45-year-old San Antonio man

experienced a throbbing frontal headache, diarrhea and fever for four days. He was employed as a meat-packing plant worker, and it was first thought that he might have contracted an infection at work. However, during an epidemiological investigation it was found that his two dogs at home had high MAT titers for three Leptospira serovars. The patient also had high titers to the same serovars, and it was concluded that his exposure was from the dogs at home. Leptospires had been cultured from the patient’s urine specimens to further confirm the diagnosis.

Case

• In December 2002, a Beagle and a crossbred dog in Dallas tested by TVMDL had high MAT titers for leptospirosis. The wife of the owner of the dogs was later diagnosed by her physician as having leptospirosis. Close contact with infected pets is enough to transmit leptospires from pets to humans.

Pathologic Lesions of Disease

• Gross findings can include petechial or ecchymotic hemorrhages on any organ, pleural, or peritoneal surface; hepatomegaly; and renomegaly. – The liver is often friable with an accentuated lobular

pattern and may have a yellowish brown discoloration. – The kidneys may have white foci on the subcapsular

surface. – Microscopic findings in the liver may include hepatocytic

necrosis, nonsuppurative hepatitis, and intrahepatic bile statis, while swollen tubular epithelial cells, tubular necrosis, and a mixed inflammatory reaction may be seen in the kidneys.

– Chronic hepatitis and chronic interstitial nephritis are described in less severe cases.

Pathological lesions of Leptospirosis

• In animals, there really isn’t any type of lesions that can be caused from the disease. Jaundice and Icterus are other types of symptoms you would see through the skin.

• Although in humans, this bacterial disease is characterized by a skin rash and flulike symptoms caused by a spirochete bacterium excreted by infected rodents

Purulolymphoplasmacytic tubulointerstital nephritis in a dog that died of leptospirosis. (Hematoxylin and eosin stain, courtesy of Noah's Arkive, The University of Georgia).

Spirochetes of Leptospira sp. appear as black threads within the lumina or renal tubules (van Orden stain, courtesy of Noah's Arkive, The University of Georgia).

Spirochetes of Leptospira sp. stain red-brown along the lumenal walls of renal tubules (immunoperoxidase stain, courtesy of Noah's Arkive, The University of Georgia).

Recommended Treatment

• Leptospirosis is treated primarily with antimicrobial therapy. In uncomplicated infections that do not require hospitalization, oral doxycycline has been shown to decrease duration of fever and most symptoms.

• Hospitalized patients should be treated with intravenous fluids. A recent clinical trial showed that third-generation cephalosporins are as effective as doxycycline and penicillin in the treatment of acute disease.

Prognosis

• Prognosis depends upon how early treatment begins. Even after treatment with antibiotics, liver or kidney disease may still develop. Up to 25% of infected dogs will not survive the initial infection. 33% to 40% of infected dogs will develop chronic renal failure.

Prevention

• Vaccinate your pet yearly, vaccinated dogs may still be susceptible to infections with other serovars.

• Keep animals out of contact with potential sources of infection for example, contaminated water sources and wildlife reservoirs.

• Control the rodent population.• If a dog has been recently exposed to

leptospirosis it may be treated with oral amoxicillin or doxycycline for 7-10 days to prevent infection.

Client Education

• Animals with leptospirosis are contagious to humans and other animals.

• Supportive care is important.• Treatment and diagnosis are

expensive.• Vaccinations do not protect your dog

from other serovars with which it may come in contact.

Are vaccinations one sure way to guarantee your pet won’t

get Lepto?• Leptospira is a gram negative spirochete

bacteria that is very common in this region of the United States. There are over 250 different serovars (subtypes) and it is a zoonotic disease. Unfortunately, vaccination against one strain does not protect against the other strains.

Resources

• www.peteducation.com• www.nlm.nih.gov• www.cdc.gov• www.petside.com• www.tvmdl.tamu.edu• www.ncbi.nlm.nih.gov

References

• http://www.cdc.gov/ncidod/eid/vol11no07/04-1172.htm

• Common Disease of Companion Animals-Textbook

• http://www.merckvetmanual.com/mbm/index.jsp

• http://www.cpvh.com/Articles/88.html