Recently, an uninvited guest has entered our lives. How is the disease contracted, what are the symptoms, and what should be done in case of infection

In the past week, a disease few have never heard of before has barged into our lives: leptospirosis. According to the Israeli Ministry of Health's statement on August 13, 2018, there were 27 suspected leptospirosis cases in Israel, with hospitalization required in half of them. On the next day, laboratory tests confirmed that at least 12 of the patients were indeed infected with the disease and later this number increased to 17. All diagnosed patients recently hiked in the streams of the Southern Golan Heights, where they most likely contracted the disease. The Zavitan, Zaki, Yehudiya, and Meshushim streams have all been closed to prevent additional infections. Later, the Jilabun, Jordan Park, and the Majrase were also closed.

Leptospirosis is caused by exposure to Leptospira bacteria and is manifested in a long list of symptoms, including high fever, nausea, diarrhea, and head and muscle aches. As these symptoms are also characteristic of other diseases, such as the flu, it is often difficult to diagnose. There are a variety of Leptospira strains in nature, and only a subset are pathogenic, that is, cause disease. Pathogenic Leptospira bacteria penetrate the host's body and proceed from cell to cell until they reach the blood stream – and through it, additional tissues.

Streams in the Golan Heights were closed to the public to prevent additional infections. Photograph: Science Photo Library

Not just mice

Leptospirosis is called Achberet in Hebrew, stemming from the word for mouse (Achbar). But mice are not the necessarily to blame for the spread of the disease. Leptospira are found in the urine of various animals other than rodents, such as cows, horses, and dogs. Humans usually get infected following exposure to water contaminated with urine of infected animals – in the current outbreak, the streams of the Golan Heights. Drinking the water is not the only way to become infected: Bacteria in the water can penetrate the body through small cracks in the skin or be inhaled. An incubation period follows exposure, lasting anywhere between a few days and a month, and only then do the symptoms appear. At this point, if the disease is diagnosed, it can be cured by common antibiotics, such as penicillin or doxycycline. Therefore, it is very important to seek medical attention even if you develop only a subset of these symptoms, following a recent hike through the streams of Northern Israel.

Left untreated, the patient's condition may deteriorate. The second stage of the disease is more dangerous, but fortunately, also rarer. It may appear after a short remission, lasting a number of days, with a reduction in fever and an apparent recovery. Then, in certain cases, the disease returns in a much more violent and severe form, which may lead to meningitis, pneumonia, hepatitis, and even death. Infection during pregnancy can lead to miscarriage or fetal transmission. There have also been reports of nursing mothers who acquired the infection and transmitted it to their babies through breastmilk.

The most efficient way to prevent infection is to stay away from contaminated water, and in Israel – to follow the instructions of the Israel Nature and Parks Authority and not visit the streams closed to the public. As mentioned, Leptospira infect different animal species and are secreted in their urine, surviving on the ground or in the water for many months. Since pets and livestock are also vulnerable to the infection, and may pass it on to humans, people who work with animals are at an especially high infection risk. Transmission of the disease between humans is infrequent but can occur, mainly via sexual contact.

Every year, about a million cases of leptospirosis are reported worldwide, with a death toll of about sixty thousand. Outbreaks usually occur in tropical climates, where floods are common.

Researchers have attempted to develop a human vaccine against Leptospira for decades, with little success so far; a vaccine that is both effective and safe is still not within reach. A major challenge hampering development efforts is the variety of Leptospira strains, making it difficult to develop a vaccine to protect from them all.

Note: This article provides general information only and should not be considered as a substitute for professional medical advice.

Updated: August 16, 2018

Translated by Elee Shimshoni