Many infections occur because people come into contact with environments contaminated with rat urine, including contaminated soil, water sources, or places close to garbage. Especially outdoor locations such as ponds, puddles, and damp soil are potential breeding grounds for the disease. Particularly in tropical and subtropical regions, the risk of infection significantly increases after heavy rains or flooding.

Last year, the Guangdong Provincial Center for Disease Control issued a warning notice, emphasizing that during flooding periods, the spread of leptospirosis could potentially expand. It is well known that flooding can submerge rat nests, causing rat excrement to spread with the floodwaters to a broader area.

According to cases disclosed by Wiki at the end of 2022, a case was documented where a gentleman accidentally fell into a ditch and, a few weeks later, presented symptoms such as fever, vomiting, and diarrhea, along with conjunctival congestion and jaundice. The patient was eventually diagnosed with leptospirosis, a rare but potentially life-threatening disease. As per World Health Organization's statistics, there are about 500,000 reports of leptospirosis each year worldwide. Generally, patients with mild cases can be effectively treated with oral antibiotics, while those with severe cases require intravenous antibiotic treatment.

It is particularly important to note that individuals working in hot and humid environments, such as outdoors, in sewers, or at breeding farms, need to take appropriate protective measures during work, such as wearing long boots and waterproof gloves as personal protective equipment. Similarly, people partaking in outdoor water activities are also at risk of contracting leptospirosis.

As for pets like dogs, they are also susceptible to leptospirosis. For instance, in 2019, several areas in Sydney were affected by a rodent infestation, leading to 7 dogs contracting leptospirosis consecutively, with the suspected cause being swimming in contaminated water bodies.