Melissa Walsh

Rodents and infectious disease

Salem Press | 2011 | Salem Health: Infectious Diseases & Conditions

Essay title: Rodents and infectious disease Category: Transmission Also known as: N/A

Definition Rodent-transmitted diseases are responsible for severe and deadly illnesses among human populations.

Rodent-transmitted Infectious Diseases

Hantavirus Pulmonary Syndrome (HPS) Humans contract HPS by inhaling dried rat or mouse secretions. Though rare, HPS is a public concern because the impact to the human body is severe and can lead to death. HPS manifests itself in two stages of symptoms, which first appear about one to five weeks following exposure to the virus. With the first stage, a person experiences fever, fatigue, body ache, headache, lung congestion, nausea, diarrhea, and abdominal pain. With the second stage — known as the cardiopulmonary stage, the congestion in the lungs progresses to a cough, shortness of breath, a worsening build-up of fluid in the lungs, low blood pressure, rapid heartbeat, multi-organ failure, and respiratory distress. HPS can be diagnosed with a blood test. Patients with HPS are treated with assisted respiration, often in the intensive care unit.

Murine Typhus Humans contract Murine Typhus, a rickettsial infection caused by Rickettsia typhi, by being bitten by infected rat fleas. Domestic cats may also carry these infected fleas. Active in warm climates, Murine Typhus infection may last as long as two weeks. However, untreated, the disease can be fatal in severe cases. Following an incubation period of six to 14 days, symptoms include headache, myalgia, and rash. A bacterial disease, Murine Typhus is treated with antibiotics.

Rat-bite Fever Transmitted to humans through a bite, scratch, or ingestion of food or water contaminated with infected rat feces or other secretions, Rat-bite Fever is a bacterial illness caused by Streptobacillus moniliformis and Spirillum minus. Symptoms include fever, body ache, nausea, and rash and may progress to arthralgia, pneumonia, or meningitis. Rat-bite Fever is diagnosed by testing for the presence of the bacteria in the skin, blood or lymph nodes. It is treated with antibiotics.

Leptospirosis Leptospira bacteria is found in the urine of infected wild or domestic rodents. Humans contract Leptospirosis by handling infected rodents or ingesting water contaminated with infected rodent urine. A person will show signs of illness two to four days after exposure. Symptoms include headache, fever, abdominal pain, diarrhea, and rash. In severe cases, infected humans may suffer kidney or liver damage, meningitis, or breathing difficulty. Leptospirosis is diagnosed by testing a patient’s blood or urine and treated with antibiotics.

Eosinophilic Meningitis Humans can suffer Esinophilic Meningitis from ingesting larval stages of rat lungworm, or Angiostrongylus cantonesis, which can be hosted by by snails and slugs. Eating infected snails or vegetables that have been contaminated by snails or slugs will make a person vulnerable to contracting Eosinophilic Meningitis, which is an invasion of the central nervous system by parasites. Symptoms, including headache, fever, and nausea, may last several weeks or months. Treatment includes headache-control measures and antifungal therapy.

Prevention The best prevention of rodent-transmitted infectious diseases is indoor and outdoor rodent control. Indoor rodent-control measures include maintaining a clean kitchen, storing food and garbage in rodent-proof containers, throwing away uneaten pet food each evening, setting rodent traps, and sealing entry holes larger than 1/4 inch wide. Outdoor rodent-control measures include clearing brush and stored items away from the house foundation and removing woodpiles and other potential nesting sites. If there have been known cases rodent-transmitted infectious disease in an area, flea killer should be sprayed in sites vulnerable to rodent nesting.

Flea control is another prevention measure against rodent-transmitted infectious disease. Flea-control medicine should be administered to pets. Because contact with feral animals should be avoided, food should not be left out for birds or wild animals. Fallen fruit from trees, should be picked up and discarded.

People should not swim in water that may be contaminated with rodent urine. If walking through shallow water or ground inhabited by rodents, protective footwear and clothing should be worn.

Response If signs of rodent infestation are found in the home, such as droppings, nests, or gnawed food packaging, care should be taken in disinfecting areas rodents have been. Because dried rodent urine and feces will aerosolize during removal, a mask or respirator should be worn while cleaning an area known or suspected to have rodent infestation. Rubber gloves should be worn, and instead of sweeping or vacuuming droppings and nests, contaminated areas should be wiped clean with detergent or a hypochlorite solution. After wiping up the droppings or nesting materials, the area should be disinfected. Dead rodents should be sprayed with disinfectant, bagged with cleaning materials and thrown away in the waste disposal system recommended by the state health department.

Impact Rodents are the cause of many bacterial, rickettsial, and viral infections impacting humans. The control of rodent populations is an important function of public health management.

Melissa Walsh

Further Reading

Committee on Infectious Diseases of Mice and Rats. Companion Guide Guide to Infectious Diseases of Mice and Rats. National Academies Press, 1991.

Gratz, Norman G. Vector- and Rodent-Borne Diseases in Europe and North America: Distribution, Public Health Burden, and Control. Cambridge: Cambridge University Press, 2006.

“Health Threats from Rodent Infestation.” Infectious Disease Epidemiology Section, Louisiana Department of Health and Hospitals, 2006.

Padovan, Dennis. Infectious Diseases of Wild Rodents. Washington: Corvus Publishing Company, 2006. An inventory of documented infectious diseases originating from rodents.

Saluzzo, J. F. Emergence and Control of Rodent-Borne Viral Diseases. Paris: Gauthier-Villars, 1999.

Web Sites of Interest

All about Hantaviruses,

Centers of Disease Control and Prevention (CDC), “Rodents,”

University of California, San Francisco, “Working Safely with Animals,”

Wrong Diagnosis, “Rodent-born disease,