The Threat of Leptospirosis

CEBU, Philippines — As the Department of Health (DOH), on July 5, declared a leptospirosis outbreak in certain places in Metro Manila, the rest of the country was once again reminded to be extra careful. The outbreak declaration was prompted by a recent increase in cases of the serious bacterial disease in a number of barangays in the country’s capital.

Leptospirosis is caused by a corkscrew-shaped bacterium called Leptospira interrogans. It is sometimes referred to as “rat fever” due to the principal role that rats play in spreading the disease. Other animals can also contribute to the spread of the disease.

Leptospirosis outbreaks are usually caused by exposure to contaminated water, such as floodwaters. As the rainy days are here, many places in the country – particularly the dense urban centers – get flooded easily and frequently. Floodwaters are believed to have been a significant factor in the leptospirosis outbreak in several districts in Metro Manila.

Leptospirosis occurs worldwide, but is most prevalent in tropical and subtropical regions. The disease can be transmitted between animals and humans. As animals are commonly found among humans, there is a particular danger of contracting leptospirosis when flooding occurs, as wading in contaminated floodwaters can at times be unavoidable.

Virtually all wild and domestic mammals can harbor in their kidneys and genital tracts the bacteria that cause leptospirosis and act as source of infection to humans and other animals.

Rats are the first recognized carriers of leptospirosis and are considered the primary source of infection to human beings. Cows, carabaos, horses, sheep, goat, pigs and dogs are also considered common reservoirs of the bacteria that cause leptospirosis.

Infected animals can spread the disease in their urine, contaminating water, soil, or even food. People can become infected through common entry points like breaks in the skin, the eyes, the mouth, or the nose.

People who live in close contact with domestic animals or wildlife are at higher risk of contracting leptospirosis. Others are at risk because of their occupation, the environment they live in or their lifestyle. The main occupational groups at risk include farm and agricultural workers, pet shop workers, veterinarians, sewer workers, abattoir workers, meat handlers, military and rescue personnel, and people engaging in water sports. In some areas, practically the whole community is at risk as a result of high exposure to contaminated water in daily activities, like working in rice fields and sugarcane plantations.

The incubation period of leptospirosis is usually five to 14 days, with a range of two to 30 days. Infected individuals initially experience fever, severe headache and muscle aches, abdominal pain, and occasionally a skin rash. Patients in the later stages of the disease can suffer from jaundice, kidney failure, bleeding from the mouth or nose, and bloody urine. It can be fatal, especially without proper treatment. Person to person transmission is rare.

Leptospirosis can be difficult to diagnose, as most of its symptoms can appear to be very similar to many other diseases such as dengue, typhoid and viral hepatitis. The disease is a self-limiting and often clinically non-apparent in the majority of cases; if untreated it can progress to a more severe and potentially fatal stage. At its very early stage, it can be treated with antibiotics.

In general, the risk of infection can be minimized or eliminated by avoiding contact with animal urine and feces, infected animals or a contaminated environment. The adoption of certain measures can also help prevent the transmission of the disease:

• Covering skin lesions with waterproof dressings;

• Avoiding bodies of potentially contaminated water (including pools, ponds, rivers);

• Washing or showering after exposure to urine splashes or potentially contaminated soil or water;

• Washing and cleaning wounds after exposure to potentially contaminated elements;

• Avoiding touching sick or dead animals;

• Strictly maintaining hygienic measures during care or handling of animals;

• Where feasible, disinfecting contaminated areas (scrubbing floors in stables, butcheries, abattoirs, etc.);

• Consuming only clean drinking-water.

Once symptoms of leptospirosis occur, a doctor must be sought immediately. Treatment is most effective when started as soon as possible.