Rodent Diseases in Louisiana: Leptospirosis, Salmonella and Other Risks
Rats and mice can spread illness through their urine, droppings, saliva and bites, and some of those risks go up after floods. This guide explains the rodent diseases that matter most in Lake Charles and Southwest Louisiana, how people catch them, and how to clean up safely.
This page is general health information, not medical advice. If you feel sick after contact with rodents or floodwater, talk to a doctor.
How Do Rodents Spread Disease?
Rodents spread disease in a few main ways. The most common is through urine and droppings, which can contaminate food, kitchen surfaces, water and soil. When droppings and urine dry, stirring them up can put tiny particles into the air, which is how some viruses reach people. Bites and scratches can pass bacteria directly, and fleas and ticks that live on rodents can carry their own diseases.
Lake Charles has two conditions that raise the stakes. Warm, humid weather keeps rodents active and breeding all year, and frequent flooding spreads rodent urine through water and mud. That is why rodent control here is about health, not just noise and damage, and why rat removal includes safe cleanup.
Rodent Diseases: Quick Guide
| Disease | Main rodent source | How people are exposed |
|---|---|---|
| Leptospirosis | Rats, especially Norway rats | Water or soil contaminated with urine, especially after floods |
| Salmonellosis | Rats and mice | Food or surfaces contaminated with droppings |
| Hantavirus (Bayou virus) | Marsh rice rat | Breathing dust from dried urine, droppings or nests |
| Rat-bite fever | Rats | Bites or scratches, or food contaminated by rats |
| Lymphocytic choriomeningitis (LCM) | House mice | Contact with urine, droppings, saliva or nesting material |
| Murine typhus | Fleas on rats | Infected flea bites or flea droppings |
Leptospirosis: The Flood-Season Rodent Disease
Leptospirosis is a bacterial disease spread through the urine of infected animals, and rats are among the most important carriers. According to the CDC, the bacteria can survive in contaminated water or soil for weeks to months. People are infected through contact with that water or soil, especially through cuts or the eyes, nose and mouth, or by eating or drinking contaminated food or water.
The CDC notes that the risk often goes up after a hurricane or flood, when people wade through water or clean up mud that may contain animal urine. For a city like Lake Charles, with its bayous, ditches and flood history, that makes leptospirosis the rodent disease most worth knowing about. Norway rats, which live in burrows and drains, are the main concern.
Symptoms of Leptospirosis
Symptoms usually start 2 to 30 days after exposure and can include fever, muscle aches, headache, and nausea or vomiting. Some people have no symptoms at all. Without treatment, it can cause kidney or liver damage and other serious problems, but antibiotics work well when started early.
Wear waterproof boots and gloves when cleaning up after a flood, cover any cuts, and wash with soap and water afterward. Avoid swimming or wading in floodwater when you can.
Salmonellosis: Contaminated Food and Counters
Rats and mice can carry salmonella bacteria and leave it on food, counters, shelves and dishes as they travel. People usually get sick by eating food that rodents contaminated. Symptoms include diarrhea, fever and stomach cramps.
This is the main reason to throw away any food that rodents have chewed or that has droppings nearby, and to disinfect pantry shelves after a mouse problem. Mice control includes sanitizing the areas where mice were active.
Bayou Virus: Louisiana's Hantavirus
Hantaviruses can cause a serious lung illness called hantavirus pulmonary syndrome. Louisiana's local strain is Bayou virus, carried by the marsh rice rat, a native rodent of wetlands and marsh edges. The deer mouse that carries Sin Nombre virus in the western United States is not the main concern here.
Cases are rare. A 2025 report in the CDC journal Emerging Infectious Diseases counted seven confirmed hantavirus cases in Louisiana from 1993 to 2021, and described two more in 2022 and 2023. People are usually infected by breathing in dust from dried urine, droppings or nesting material in closed spaces like sheds, barns, cabins and attics.
Because the risk comes from dust, the cleanup method matters. Sweeping or vacuuming droppings can push virus particles into the air. The wet-cleaning steps below are the CDC's recommended way to clean up safely.
Other Rodent Diseases to Know About
Rat-Bite Fever
Rat-bite fever is a bacterial infection spread through rat bites or scratches, and sometimes through food or water contaminated by rats. It can cause fever, rash and joint pain. Never handle a live rat with bare hands, including one caught in a trap.
Lymphocytic Choriomeningitis (LCM)
LCM is a virus carried by house mice. People can be infected through contact with mouse urine, droppings, saliva or nesting material. Many infections are mild, but it can be serious for pregnant women and people with weakened immune systems, which is one more reason not to live with a mouse problem.
Murine Typhus and Flea-Borne Illness
Some diseases come from the fleas that live on rats rather than the rats themselves. Murine typhus spreads through infected fleas. When rats die or leave, their fleas may look for new hosts, including pets and people, so flea control on pets matters during and after rodent removal.
Allergies and Asthma
Mouse and rat urine, droppings and dander are known indoor allergens. In homes with a long-running mouse problem, they can trigger allergy and asthma symptoms, especially in children.
How to Clean Up Rodent Droppings Safely
For small areas, you can clean up yourself by following the CDC's steps. For large contamination, attics, crawl spaces or nests, use a professional attic cleanup crew with HEPA equipment.
- Open doors and windows for 30 minutes before you start, to air out the space.
- Put on rubber or plastic gloves.
- Spray the urine and droppings until very wet with an EPA-registered disinfectant or a bleach solution of 1 part bleach to 9 parts water.
- Let it soak for 5 minutes, or as long as the product label says.
- Wipe it up with paper towels and throw them in a covered trash can.
- Mop or wipe the area again with disinfectant.
- Wash gloved hands, remove the gloves, then wash your hands with soap and warm water.
The CDC warns that sweeping or vacuuming rodent urine, droppings or nests can put tiny droplets containing viruses into the air. Always wet them first.
When to See a Doctor
Talk to a doctor if you develop a fever, muscle aches, headache, vomiting, rash or trouble breathing in the weeks after contact with rodents, their droppings, or floodwater. Tell the doctor about the exposure, since it helps them think of the right tests. Seek care quickly for any rat bite, and clean the wound right away with soap and water.
Removing the rodents and sealing the house cuts off the source. Rodent proofing closes the gaps, with a 90-day guarantee on sealed points.
Rodent Disease FAQs
Can you get sick from mouse droppings?
Yes. Mouse droppings and urine can carry bacteria such as salmonella and viruses such as LCM. The risk is lower when droppings are cleaned up with the wet method and food that mice touched is thrown away.
Is hantavirus common in Louisiana?
No. Louisiana's Bayou virus is rare, with only a small number of confirmed cases since 1993. It is serious, though, so safe cleanup of droppings and nests still matters.
Why does flooding increase leptospirosis risk?
Floodwater picks up animal urine from soil and other surfaces, and people often wade through it or clean up contaminated mud. The bacteria can survive in water and soil for weeks to months.
Do rodents in the attic make the air in my house unsafe?
Heavy contamination near an air handler or return duct can carry dust and odor into living spaces. Removing soiled insulation and sealing duct gaps lowers that risk.
Can my dog catch diseases from rats?
Yes. Dogs can get leptospirosis from water or soil contaminated by rat urine, and pets can pick up fleas from rats. Ask your veterinarian about vaccines and flea control.
Should I hire someone to clean up droppings?
For a small spot, the CDC steps above are enough. For attics, crawl spaces, nests, or anyone in the home with health concerns, professional cleanup with HEPA equipment is safer.
Sources
- CDC: About Leptospirosis
- CDC: How to Clean Up After Rodents
- CDC Emerging Infectious Diseases: Bayou Virus cases in Louisiana
- LSU AgCenter: Rats and Mice
Related Guides
Learn to tell rodents apart in the roof rat and house mouse guides, or return to our Lake Charles rodent removal service overview.
Remove the Source, Clean Up Safely
Rodents trapped out, gaps sealed, and droppings cleaned up the way the CDC recommends.
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