Recent leptospirosis outbreak: an urgent warning around the globe, genomic features, diagnosis, and treatment procedures—correspondence

Dear Editor,

Leptospirosis is a bacterial infection that has occurred due to Leptospira. It may be encountered in people and animals, and it is most prevalent in tropical regions with humid weather, such as the north of Queensland or southeast Asia. Several strains of the bacterium Leptospira are capable of causing severe illness, which may be transmitted from animals to humans. These bacteria are widespread and may be encountered in soil and water all around the globe. The majority of human occurrences of leptospirosis in the United States are attributable to engagement in water-based recreational activities1,2.

Adolf Weil was the first person to describe leptospirosis in 1886. He referred to it as an ‘acute infectious disease with enlargement of the spleen, jaundice, and nephritis’. Before Weil’s explanation, the disease was alluded to as ‘rice field jaundice’ in ancient Chinese texts, ‘autumn fever’, ‘seven-day fever’ in Japan; in Europe and Australia, the ailment was affiliated with certain and occupations and formally known as such as ‘cane-disease’, and cutter’s ‘swine-disease’, herds. In New Zealand, the disease was formerly referred to as ‘black jaundice’ or ‘dairy farm fever’. During the years 1616–19, it was hypothesized that an outbreak of leptospirosis was responsible for the deaths of a large number of Native Americans living along the coast that is now New England3,4.

Recently, a significant number of patients all across the globe have once again been infected with this pathogenic bacterial infection5. More than 20 instances of leptospirosis, including three fatalities, had been recorded in the Lindi Region of the United Republic of Tanzania as of 8 August 2022. These cases have been spread among two districts. Fifteen of these patients have tested positive in a laboratory test. The majority of patients are male, and it has been stated that all of them are farmers. Occupational exposure is thought to be the most probable cause of infection in the infected population. Although reports of epidemics of leptospirosis are very uncommon in the United Republic of Tanzania, the disease has been known to occur there. The number of cases often varies seasonally and tends to rise in correlation with increased rainfall or warmth. The case fatality rate is 6.7%. The ages of the patients differed significantly, from 18 to 77 (median age 45) years, with the vast majority (n=15; 75%) falling between the ages of 31 and 60. Most of the patients diagnosed (15 out of 20) were men (75%), and they were all farmers working out of a makeshift camp6.

Leptospirosis is a zoonotic disease. There are 4 627 366 base pairs (bp) in the Leptospira genome, which comprises two circular chromosomes: chromosome I, which has 4 277 185 bp, and chromosome II, which has 350 181 bp. Due to the flexibility in the length of their genomes, bacteria can adapt to a broad variety of hosts and survive in a wide range of environments. On the other hand, in-depth research and comprehension of the molecular pathogenesis and virulence development of Leptospira spp. are currently unknown7.

The primary mode of transmission of leptospirosis is by touching water or soil that the urine of sick animals has tainted. People are at risk of contracting the illness if they engage in activities such as swimming or wading in fresh, unchlorinated water contaminated by animal urine or if they come in contact with moist soil or plants tainted by animal urine. There is no evidence that chlorinated water, such as that found in swimming pools or the drinking water provided by municipalities, may spread leptospirosis. The infection may also be passed on by physical contact with an affected animal’s urine, blood, or tissues. The bacteria can penetrate the body via cuts in the skin or through the soft tissues that line the interior of the mouth, nose, and eyes8.

The clinical manifestations of leptospirosis are very variable and lack diagnostic specificity. Infected patients have been documented as presenting with typical clinical manifestations. These symptoms include severe weakness, fever, vomiting, abdominal discomfort, diarrhea, refusal to eat, vomiting, and abdominal pain9.

Antibiotics, such as doxycycline or penicillin, may be used to treat leptospirosis. For the best results, treatment should commence as soon as possible after symptoms appear. Antibiotics injected intravenously could be recommended for patients whose manifestations are very extreme. Those who believe they may have leptospirosis should get in touch with a qualified medical professional as soon as possible. Sometimes, an infected person should be admitted to a hospital10.

Prevention is better than cure. So, although different antibacterial agents are available, proper preventive care should be followed. These, including keeping rodent infestations (such as rats, mice, or other animal pests) under control, may assist in preventing infections caused by leptospirosis. The bacterium responsible for this illness may be carried and transmitted by rodents. Get your pet immunized against leptospirosis. The vaccination does not provide complete protection against the disease. This is due to the fact that there are several forms of leptospirosis caused by bacteria. Still, the vaccination does not confer protection against all of these types. Even if your pet recovers from leptospirosis, it is still vital to re-vaccinate it against the disease since it can get infected with a new strain of leptospirosis. The owners of infected pets are responsible for protecting themselves and others from contracting the illness that their animals may be carrying. The most common way leptospirosis can be passed from animals to people is by directly or indirectly interacting with infected animal tissues, organs, or urine. So, vaccination may reduce the chance of infection11.

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Author contribution

S.A.: conceptualization, writing − original draft preparation. N.N.Z., Md.M.R.: writing and editing. All authors have reviewed and approved the final version of the manuscript prior to submission.

conflicts of interest disclosure

The authors declare no conflict of interest, financial or otherwise.

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Guarantor

Md. Mominur Rahman (corresponding author) takes full responsibility for the work and/or the conduct of the study, had access to the data, and controlled the decision to publish.

Data availability statement

All data are available within the manuscript.