There is a wide range of symptoms that can occur in humans who are affected by leptospirosis even though some people will be asymptomatic [8]. Since the disease is considered a biphasic disease it presents initially through flu-like symptoms including malaise, fever, chills, myalgia and headache.

The mild form of the disease is considered to be the first phase and will usually resolve after 3 to 7 days. If the disease progresses to the secondary stage, liver damage and jaundice can occur along with renal failure, lung infection, meningitis, and encephalitis.

General symptoms are:

• Anorexia
• Conjunctivitis
• Cough
• Pharyngitis
• Diarrhea 
• Fever
• Headache
• Myalgia
• Nausea
• Vomiting
• Rash
• Abdominal pain
• Rigors

After the initial seven to ten days following exposure, the microorganism related to the disease can be found in fresh urine as well as in blood and cerebrospinal fluid [9]. 

During the workup for the disease diagnostic testing can include blood cultures and serum tests that will be tested against a panel of possible strains. Kidney function tests will also be done including blood urea nitrogen, and creatinine tests. Liver function tests will also be done. Diagnosis will then be confirmed through enzyme-linked immunosorbent assay (ELISA) tests and polymerase chain reaction (PCR).

In mild cases of leptospirosis, antibiotics like amoxicillin, ampicillin, doxycycline, and penicillin G. are considered to be the most effective, but the use is still controversial. If the case proves to be more severe, cefotaxime or ceftriaxone should be prescribed [10].

Some serious cases that affect the kidneys and need dialysis may be treated with glucose and salt solution infusions in addition to the dialysis. Renal failure, high potassium levels, and other associated conditions will need their own treatment.

In the mild form, which accounts for 90 percent of the reported cases, leptospirosis is usually not fatal [7]. The mortality rate increases in the more severe form of the disease.

When the disease affects humans, the elderly community and people with compromised immune systems are most at risk in terms of mortality. These deaths usually occurs due to renal failure, acute respiratory distress syndrome, liver failure, meningitis and hemorrhage.

Leptospirosis is caused by the Leptospira species which is a spirochaete bacterium. In the US and Canada there are about five serotypes of the bacterium that lead to disease. There are [2]:

• Bratislava
• Canicola
• Grippotyphosa
• Icterohaemorrahagiae
• Pomona

Other than these serotypes there are a number of strains that are considered to be more lethal. Arguments over strain identification come about due to the nature of the species. Technologies, including polymerase chain reactions, which can help with strain identification.

The primary animal hosts are rates, moles, and mice, but any animal can carry and transmit the disease. This can include cows, dogs, hedgehogs, rabbits, raccoons, sheep, deer, opossums, skunks, and marine mammals. The bacteria and subsequent disease leptospirosis is transmitted via the urine or other bodily fluid of an infected animal. It can remain contagious as long as the fluid in question remains moist [3]. Secondary hosts, like humans, can also spread the disease after contracting it.

The disease doesn’t seem to have a preference for gender, race, or age and can be contracted by anyone who comes into contact with the bacteria. There are more instances of the disease in tropical regions where there can be 10 to 100 reported cases in 100,000 population. Temperate regions can see much smaller numbers (0.02 in 100,000). Annually, there are between 7 and 10 million people affected by leptospirosis [4].

Leptospirosis is caused by the Leptospira species of bacteria which are coiled aerobic gram-negative organisms. They are able to burrow into a host’s tissue due to their hooked ends and paired axial flagella [5]. 

The most important source for the pathogens is the urinary shedding of infected animals. Humans become infected with the disease after coming into contact with infected urine or contaminated water, food, bedding, soil/mud, or aborted tissue from an infected animal. The bacteria can live for as long as 16 days in fresh water and for 24 days in soil if conditions are appropriate.

Occupations at risk include slaughterhouse workers, sewage workers, veterinarians, farmers, waste disposal facility workers and military personnel. Recreational activities such as swimming, windsurfing, kayaking or rowing may also result in contracting the disease from contaminated water or soil.

The disease can enter the host via:

• Abrasions 
• Animal bites
• Inhalation of aerosolised body fluid
• Mucous membranes or conjunctiva
• Placenta during pregnancy

With leptospirosis, the most common finding is vasculitis of the capillaries which is seen in each affected organ system. This condition causes probably most of the clinical findings [6].

Since this disease is contracted by coming into contact with infected animal body fluids, the best form of prevention is to avoid coming into contact with the bodily fluids of primary hosts. If dealing with these animals or any animal that might be infected, all surfaces should be thoroughly cleaned and sanitized. Gloves should also be worn at all times in order to avoid contact with contaminated surfaces or animals. If it’s possible that another animal, like a pet, came into contact with rodent droppings or urine, they should be monitored for symptoms.

Leptospirosis is an infectious disease that is caused by the pathogenic spirochetes of the genus Leptospira [1]. It is seen more often in tropical areas where the weather is warmer but, with an increase in global warming, the infectious disease is occurring more frequently than usual making it the most common zoonosis in the world. The only areas where no cases of leptospirosis are reported, are the Polar regions.

Humans that are affected by leptospirosis are considered to be accidental hosts in most cases and aren’t thought to be carriers of the Leptospira species. The animals that are mostly affected by this disorder are various mammals, reptiles, birds and amphibians. The humans who are accidentally contracting the disease do so when they come into contact with the body fluid of an infected animal or through exposure to contaminated soil or water.

Leptospirosis is a disease that mainly affects animals but can affect humans if they come into contact with the bodily fluid of an infected animal. If the disease progresses without treatment it can be fatal.

Most commonly, rodents carry the disease. Steering clear of these host animals and cleaning up after them if they get into your home is essential in preventing the spread of the disease.

If a human or animal does contract leptospirosis, it can be treated with antibiotics and has a high cure rate when caught in the mild state. While severe forms of the disease are rare, it can happen and lead to other problems like renal failure.

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