Can leptospirosis spread to humans or other pets?

Leptospira spreads through contaminated urine or water and poses a risk to both humans and other animals. If infection is suspected, minimise contact and consult your vet or a medical professional.

How do vets test for leptospirosis?

Vets commonly use blood or urine samples for serology or PCR testing. The choice of test and timing of sampling can affect accuracy — your vet will advise on the most appropriate approach.

Is hospitalisation usually needed after infection?

Hospitalisation depends on disease severity. If dehydration, persistent vomiting, or organ dysfunction is present, the vet may recommend admission for supportive treatment and monitoring. Follow your vet's guidance.

What information can I record or prepare at home to help with diagnosis?

Track appetite, water intake, vomiting, and urination patterns. Film a short video showing your pet's demeanour and activity. Bring a fresh urine sample and a list of current medications to the appointment.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Leptospirosis in Dogs & Cats: Symptoms, Diagnosis & Treatment Guide [2025]

Leptospirosis is a zoonotic disease that can damage liver and kidney function. Prompt antibiotic treatment is essential, and vaccination is available for prevention.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: AVMA, WSAVA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek Emergency Care Immediately

•Persistent lethargy or complete unresponsiveness to surroundings
•Frequent vomiting with inability to eat or drink
•Blood in urine or dark-colored urine accompanied by marked weakness

Schedule a Clinic Visit Soon (within 24–72 hours)

•Noticeably poor energy persisting for more than 24 hours
•Significant loss of appetite or continuous refusal to eat for more than 24 hours
•Persistent diarrhea with obvious signs of dehydration

01What symptoms indicate something is wrong?

Leptospirosis in dogs and cats often presents with non-specific systemic signs. Early stages may show only mild lethargy or reduced appetite; as the disease progresses, liver and kidney function may be affected, leading to vomiting, diarrhoea, or changes in urination.

Persistent lethargy or noticeable drowsiness with reduced activity
General weakness and decreased willingness to walk or play
Noticeably reduced appetite or persistent refusal to eat
Ongoing or repeated vomiting and diarrhoea accompanied by loss of appetite
Changes in urination frequency, volume, or colour (e.g. darker urine or blood in urine)
If multiple symptoms occur together, seek veterinary assessment promptly

Seek emergency care immediately if you notice the following symptoms:

⚠️ Persistent high fever or abnormal body temperature with severe lethargy
⚠️ Blood in urine or difficulty urinating
⚠️ Continuous vomiting preventing the pet from eating or drinking

02How to assess symptoms at home: observation tips and when to go to emergency

Home observation and record-keeping help your vet assess disease progression and severity. Note times and frequency carefully, and keep any samples or video footage that may be useful.

Record when symptoms first appeared and how they change each day
Track appetite, actual food intake, and water consumption daily
Note the number of vomiting episodes, timing, and the content of vomit
Record bowel movement frequency, stool consistency, and colour changes
Monitor urination frequency and watch for abnormal urine colour or straining
Film a short video of your pet's demeanour and activity level to show the vet at the appointment

03How will the vet diagnose the condition? Common diagnostic tests

After arrival, the vet will perform a physical examination alongside laboratory tests to confirm infection and assess organ function. Advanced imaging or pathogen testing may be arranged if needed.

Full physical examination

assessing mentation, mucous membrane colour, and degree of dehydration

Complete blood count and biochemistry panel

evaluating liver, kidney, and electrolyte status

Urinalysis and urine culture or microbiological testing

Pathogen testing (e.g. blood or urine PCR) to confirm infection

Imaging (ultrasound or advanced imaging) if needed to evaluate complications

04How is leptospirosis treated and managed? Medication, diet, and care guide

Treatment focuses on antibiotic therapy and supportive care. Regular blood and urine monitoring is needed to track organ function recovery.

Follow the vet's instructions for antibiotic treatment and supportive care
Severe cases may require hospitalisation for intravenous fluids, electrolyte support, and close monitoring
Adjust diet and ensure adequate hydration and electrolyte intake
Attend regular follow-up appointments to monitor blood and urine test results
Further imaging or specialist referral may be arranged to confirm recovery

05What to prepare before the vet visit: key information to help the vet diagnose quickly

Write down when symptoms started and how they have changed each day

Prepare a log of recent food intake and water consumption

Bring a small fresh urine sample in a sealed container if possible

List all current medications, vaccines, and supplements

Film a short video of any vomiting episodes or your pet's activity level to bring to the appointment

Call ahead to book an appointment at a clinic equipped to run blood and urine tests

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.