Zoonotic diseases are those that can be passed from animals to humans. These diseases can be viral, bacterial, fungal or parasitic. They vary from mild to severe and can be fatal (Seymour, 2018). There are approximately 40 different zoonotic diseases in the UK (Cooper et al., 2020) and leptospirosis is one of these diseases.
Leptospirosis is a bacterial infection caused by Leptospira bacteria that has become more and more prevalent in both human and veterinary medicine (DiPrete, 2019). Many mammals are capable of carrying the disease, which can be spread among themselves and humans, but common species that carry the disease are cattle, pigs and rodents (Public Health England, 2013). Leptospirosis, which affects the kidneys and liver, is spread via urine and the organism enters the body through the eyes, nose, mouth or open wounds. It can also live in wet ground and freshwater. Dogs are at risk if they are in contact with other infected dogs, if they lick or sniff infected urine, if they spend a lot of time on farms with infected animals or if they are in contact with infected lakes or rivers (PDSA, 2020).
Dogs are at risk if they are in contact with other infected dogs, if they lick or sniff infected urine, if they spend a lot of time on farms with infected animals or if they are in contact with infected lakes or rivers (PDSA, 2020)
The incubation period of leptospirosis is approximately seven days. There are different forms of the bacterium, each causing a different severity of clinical signs. In severe cases, patients can go rapidly downhill in a matter of hours and sudden death is possible. It is also thought that young animals are more severely affected (Cooper et al., 2020). There are two main Leptospira interrogans strains (serovars) that are significant in dogs: Canicola, which causes acute nephritis, and Icterohaemorrhagiae, which causes liver damage, vascular damage and haemorrhage (Lane and Cooper, 1999).
There is a vaccination available for leptospirosis and keeping up to date with this vaccine is the best prevention. The vaccination covers a variety of strains and is repeated yearly for maximum effect.
Lethargy, vomiting, diarrhoea, polyuria, polydipsia and inappetence can all be signs of leptospirosis affecting the renal system, while tachypnoea and dyspnoea are signs of pulmonary haemorrhage. In early stages of the disease, pyrexia, muscle pain and reluctance to move can all be signs (Sykes et al., 2011). Jaundice may also be seen in patients where the disease is affecting the liver.
Some patients with leptospirosis may show mild or no clinical signs, while others will develop severe illness. Furthermore, not all clinical signs will be seen in all patients. Clinical signs can progress quickly and if any of them are present owners should seek veterinary advice immediately so treatment can be started if necessary.
Leptospirosis cannot be diagnosed with an in-house blood test. If the standard haematology and biochemistry blood test results are abnormal and leptospirosis is suspected, further tests will be needed to confirm diagnosis.
A polymerase chain reaction (PCR) test or a microscopic agglutination test (MAT) are the most effective forms of diagnosis
A polymerase chain reaction (PCR) test or a microscopic agglutination test (MAT) are the most effective forms of diagnosis. The PCR test will test for any Leptospira bacteria present in the dog’s blood or urine, whereas the MAT will check for antibodies against Leptospira. Often, it is decided that both tests will be run to confirm diagnosis (Ruotsalo et al., 2021).
The best treatment for leptospirosis is still unknown but antibiotics and supportive care of the affected organs are the main forms of treatment used.
The antibiotic of choice for leptospirosis is doxycycline which should be given as soon as the disease is suspected and continued for at least two weeks after clinical signs have subsided (Sykes et al., 2011). The level of supportive care chosen will be different for each patient depending on the severity of clinical signs. Intravenous fluid therapy will be needed to support the kidneys and maintain hydration and electrolytes. Anti-emetics and analgesia should also be considered. If patients are inappetent for a long period of time, a feeding tube can be placed to maintain nutrition. In severe cases, a blood transfusion may need to be considered if haemorrhage is occurring (Sykes and Reagan, 2019).
If a patient has been diagnosed with leptospirosis and has been living with another dog, the exposed dog should be given a course of antibiotics as a precaution (Sykes and Reagan, 2019).
Leptospirosis can be very serious. If a patient is showing mild clinical signs and the owner seeks veterinary treatment quickly, the prognosis may be good and there is a chance of a full recovery; however, the more severe cases will often have a poor prognosis.
Working in veterinary practice increases the risk of coming into contact with a zoonotic disease, so precautions should be taken to minimise this risk.
Washing hands thoroughly after handling animals, wearing personal protective equipment (PPE) and not preparing food for human consumption near animals are all ways to reduce exposure to a zoonotic disease (Lane and Cooper, 1999). Reducing the number of staff who handle and treat patients with leptospirosis should be considered as it will limit the number of people being exposed to the disease and therefore reduce the risk of transmission.
If there is a suspected case of leptospirosis in the hospital, the patient should be kept in isolation and be barrier nursed … full PPE should be worn, including gloves, gowns and masks, which should be single use and put into the infectious waste bin after use
If there is a suspected case of leptospirosis in the hospital, the patient should be kept in isolation and be barrier nursed. This is to protect both the veterinary team and the rest of the patients from contracting the disease. Full PPE should be worn, including gloves, gowns and masks, which should be single use and put into the infectious waste bin after use. The patient should be in an isolation kennel with everything needed for treatment in the isolation unit (Figure 1), minimising the need for nurses to go back and forth to the rest of the hospital. All clinical waste from these patients should be disposed of using an infectious waste bag, and all bedding should be washed on its own, on a hot wash to kill any bacteria present.
Once the patient has left, the isolation unit should be deep cleaned thoroughly before any other patient uses the facilities.
Leptospirosis can be prevented by keeping up to date with vaccinations; however, if present, it can often have a poor prognosis. It is also important to remember that leptospirosis is a zoonotic disease so handling these patients with care and PPE is essential.