Can Rats Harm Humans

Rat-Borne Diseases

Bacterial Infections

Leptospirosis

Leptospirosis is a bacterial infection caused by pathogenic Leptospira species that frequently circulate among rodent populations. In urban and rural settings, rats serve as primary reservoirs, shedding organisms in urine that contaminates water, soil, and food. Human exposure occurs through skin abrasions, mucous membranes, or ingestion of contaminated material, making the disease a direct consequence of rat‑human interaction.

Typical clinical manifestations include:

Fever and chills
Headache, muscle pain, and abdominal discomfort
Conjunctival suffusion
Jaundice, renal dysfunction, and pulmonary hemorrhage in severe cases

Incubation ranges from 2 to 30 days; early symptoms mimic flu, while delayed organ involvement can be fatal without prompt therapy.

Prevention strategies focus on minimizing contact with rodent urine:

Ensure proper sanitation and waste management to deter rat infestation.
Use protective gloves and waterproof clothing when handling potentially contaminated water or soil.
Provide clean drinking water and avoid swimming in stagnant ponds.

If infection is suspected, administer doxycycline or azithromycin for uncomplicated disease, and intravenous penicillin or ceftriaxone for severe presentations. Early treatment reduces morbidity and mortality, underscoring the public‑health importance of controlling rat‑borne leptospirosis.

Salmonellosis

Salmonellosis is an infection caused by Salmonella bacteria, which can affect the gastrointestinal tract of humans. The bacteria are transmitted through ingestion of contaminated food, water, or direct contact with infected animals.

Rats frequently harbor Salmonella in their gastrointestinal tract and excrete the pathogen in feces, urine, and saliva. Contamination of grain stores, kitchen surfaces, and water sources occurs when rodent droppings mix with food or become aerosolized during cleaning activities. Human exposure results from handling tainted products or entering environments where rat waste is present.

Clinical manifestations include diarrhea, abdominal cramping, fever, and nausea. Dehydration may develop rapidly, especially in children and the elderly. Invasive disease can progress to bacteremia, septic arthritis, or osteomyelitis, requiring hospitalization.

Outbreak investigations have linked several food‑borne salmonellosis incidents to rodent infestations in warehouses, restaurants, and residential kitchens. Surveillance data show that a measurable fraction of sporadic cases trace back to rodent‑associated contamination.

Preventive actions:

Implement integrated pest‑management programs to reduce rodent populations.
Seal entry points, maintain clean storage areas, and eliminate food debris.
Store food in rodent‑proof containers; discard damaged packaging.
Wash hands thoroughly after handling waste, cleaning surfaces, or any rodent contact.
Cook food to internal temperatures that destroy Salmonella (≥ 165 °F / 74 °C).

Treatment focuses on fluid replacement and electrolyte balance. Antibiotic therapy is reserved for severe or systemic infection, guided by susceptibility testing.

Rats represent a credible source of Salmonella exposure, underscoring the need for rigorous rodent control and hygiene practices to protect public health.

Rat-Bite Fever

Rat‑Bite Fever (RBF) is a bacterial infection transmitted to humans through bites, scratches, or contact with the urine or feces of infected rodents, most commonly rats. The disease is caused by Streptobacillus moniliformis in North America and by Spirillum minus in Asia. Both organisms are part of the normal oral flora of rats and can enter the human bloodstream when the skin barrier is breached.

Typical clinical presentation develops 2–10 days after exposure and includes:

Sudden fever and chills
Headache and muscle aches
Joint pain or migratory polyarthritis
Rash consisting of small, red macules or petechiae, often on the extremities
Nausea, vomiting, or abdominal discomfort

Severe complications may involve endocarditis, meningitis, or sepsis, underscoring the need for prompt medical attention. Laboratory confirmation relies on blood cultures, which grow the causative organism in the majority of cases, or on polymerase chain reaction assays when cultures are negative.

First‑line therapy consists of a 10‑day course of oral doxycycline or a 7‑day regimen of intravenous penicillin G for patients unable to tolerate oral medication. Early treatment markedly reduces morbidity and mortality; untreated RBF carries a case‑fatality rate of up to 10 %.

Prevention strategies focus on minimizing direct contact with rodents and their secretions:

Wear thick gloves when handling rats, especially in laboratory or pest‑control settings.
Disinfect cages, traps, and surfaces with a bleach solution (1 % sodium hypochlorite).
Promptly clean any bite or scratch with soap and water, then seek medical evaluation.
Educate pet owners, wildlife workers, and veterinarians about the risks associated with rodent bites.

Populations at higher risk include laboratory personnel, pest‑control workers, pet rat owners, and individuals living in infested housing. Surveillance data indicate that RBF cases are rare in regions with strict rodent‑control programs, but sporadic outbreaks continue to occur where human‑rodent interactions are frequent.

Understanding the etiologic agents, clinical features, and preventive measures enables health professionals to diagnose Rat‑Bite Fever rapidly and to implement effective treatment, thereby reducing the health impact of rodent‑related infections.

Viral Infections

Hantavirus

Rats serve as primary reservoirs for hantaviruses, maintaining the virus in wild populations without showing disease. The virus persists in the rodents’ kidneys, salivary glands, and urine, and spreads through aerosolized particles from dried droppings, urine, or saliva. Human exposure typically occurs when individuals enter infested spaces—such as barns, sheds, or homes—and disturb contaminated material.

Infection in humans manifests as two clinically distinct syndromes.

Hemorrhagic fever with renal syndrome (HFRS) presents with fever, headache, abdominal pain, and acute kidney injury, often accompanied by hemorrhagic manifestations.
Hantavirus pulmonary syndrome (HPS) begins with flu‑like symptoms, rapidly progresses to severe respiratory distress, and can result in fatal pulmonary edema. Mortality rates exceed 30 % for HPS and range from 1–15 % for HFRS, depending on the viral strain and healthcare response.

Incidence varies geographically; Asia and Europe report higher HFRS cases linked to the Seoul and Puumala viruses, while the Americas experience HPS primarily from the Sin Nombre virus. Outbreaks correlate with increased rodent populations, climatic conditions that favor rodent breeding, and human activities that disturb rodent habitats.

Preventive measures focus on rodent control and exposure reduction: sealing entry points, maintaining clean storage areas, using protective equipment when cleaning contaminated sites, and employing wet methods to suppress dust. No specific antiviral therapy exists; supportive care, early intensive respiratory management, and, for HFRS, ribavirin administration improve outcomes.

Lymphocytic Choriomeningitis (LCMV)

Rats serve as natural reservoirs for Lymphocytic Choriomeningitis Virus (LCMV), a rodent‑borne pathogen that can infect humans through direct contact with contaminated urine, feces, saliva, or nesting material. The virus is present in many wild and laboratory rat populations worldwide, and infection in humans occurs sporadically when exposure pathways are not controlled.

Human LCMV infection typically begins with a flu‑like prodrome: fever, headache, muscle aches, and malaise. In a minority of cases, the disease progresses to aseptic meningitis or encephalitis, presenting with neck stiffness, photophobia, altered mental status, and, occasionally, seizures. Pregnant women face additional risk; transplacental transmission may cause fetal hydrocephalus, intracranial calcifications, or miscarriage.

Diagnosis relies on serologic testing for LCMV‑specific IgM and IgG antibodies or detection of viral RNA by polymerase‑chain‑reaction assays. No antiviral therapy has proven efficacy; management focuses on supportive care, including analgesics, antipyretics, and, when indicated, hospitalization for neurologic monitoring.

Preventive measures reduce the likelihood of transmission:

Seal entry points to buildings; eliminate gaps around doors, windows, and utility penetrations.
Maintain sanitation: remove food residues, store waste in sealed containers, and clean spills promptly.
Implement rodent‑control programs using traps or certified exterminators; avoid indiscriminate poisoning.
Use personal protective equipment (gloves, masks) when handling rodents or cleaning contaminated areas.
Educate laboratory personnel and pet owners about LCMV risks and enforce strict biosafety protocols.

Public health surveillance tracks LCMV cases, enabling timely response to outbreaks. Awareness of rat‑associated LCMV underscores the broader health implications of rodent infestations and informs risk‑reduction strategies.

Parasitic Infections

Toxoplasmosis

Rats can act as reservoirs for Toxoplasma gondii, the protozoan that causes toxoplasmosis. The parasite completes its sexual cycle in felids, but rodents acquire infection by ingesting oocysts from contaminated soil, water, or food. Infected rats develop brain cysts that persist for life, making them a chronic source of the parasite.

Human exposure occurs through several pathways:

Consumption of undercooked meat from animals that have eaten infected rodents.
Inhalation of aerosolized oocysts from dust or cat litter that has been contaminated by rat feces.
Direct handling of rats or their carcasses without proper protective equipment.

Clinical manifestations in immunocompetent adults are usually mild flu‑like symptoms or asymptomatic seroconversion. Immunosuppressed individuals and pregnant women face severe risks, including encephalitis, ocular disease, and congenital infection that can cause fetal brain damage and miscarriage.

Control measures focus on reducing rat populations in residential and agricultural settings, ensuring proper sanitation to limit environmental contamination, and educating at‑risk groups about safe food handling and personal protective practices. These actions lower the probability that rodent‑borne T. gondii reaches humans.

Trichinellosis

Trichinellosis is a parasitic disease caused by the nematode Trichinella spp., which can be transmitted to humans through the consumption of raw or undercooked meat that contains encysted larvae. Although wild rodents, including rats, are common reservoirs, infection in people typically results from eating contaminated pork, game, or other meat products. When rats harbor Trichinella, they can contaminate the environment, increasing the risk that domestic animals or humans encounter infected tissue.

The disease progresses through three phases:

Intestinal phase (1–2 days): larvae released from cysts invade the small‑intestinal mucosa, causing abdominal pain, diarrhea, and nausea.
Muscular phase (2–8 weeks): larvae migrate to skeletal muscle, where they encyst, producing fever, facial edema, muscle tenderness, and weakness.
Chronic phase (months): persistent muscle inflammation may lead to prolonged fatigue and reduced mobility.

Key points for risk assessment:

Rats themselves do not directly infect humans; transmission requires ingestion of infected tissue.
Presence of rats in food‑production or storage areas elevates the probability of cross‑contamination of meat supplies.
Proper cooking (internal temperature ≥71 °C) destroys Trichinella larvae, eliminating infection risk.
Routine inspection of meat for cysts and adherence to hygiene standards in slaughterhouses reduce exposure.

Control measures focus on rodent management, strict sanitation in processing facilities, and public education about safe cooking practices. By addressing these factors, the indirect threat posed by rats carrying Trichinella can be effectively mitigated.

Physical Harms from Rats

Rat Bites

Severity of Bites

Rat bites vary from superficial punctures to deep tissue lacerations. Superficial injuries typically involve a single puncture of 2–3 mm, cause minimal bleeding, and heal within a few days with basic wound care. Deeper bites may transect muscle, tendon, or nerve fibers, leading to significant hemorrhage, impaired function, and prolonged recovery.

Health risks associated with rat bites include:

Bacterial infection: Streptobacillus moniliformis (rat‑bite fever) and Leptospira spp. are the most common pathogens; infection rates rise with delayed cleaning.
Tetanus: Clostridial spores can colonize the wound; vaccination status determines necessity of prophylaxis.
Secondary complications: Abscess formation, cellulitis, and, rarely, septic arthritis when the bite penetrates joint capsules.

Clinical management requires immediate irrigation with sterile saline, debridement of devitalized tissue, and coverage with an appropriate antiseptic dressing. Empiric antibiotic therapy, typically a combination of doxycycline and ampicillin‑sulbactam, addresses the most likely organisms while culture results are pending. Tetanus immunization should be verified, and rabies prophylaxis is unnecessary unless the animal is a known reservoir for the virus.

Prognosis correlates directly with bite depth and promptness of treatment. Superficial punctures resolve without sequelae when cleaned within hours. Deep wounds, especially those involving neurovascular structures, may result in permanent functional deficits if intervention is delayed.

Risk of Secondary Infections

Rats carry pathogens that can be transferred to people through bites, scratches, or contamination of food and surfaces. When a primary infection occurs—such as a rat bite introducing Streptobacillus moniliformis—secondary bacterial or viral agents may exploit the compromised tissue, leading to more severe disease courses.

Common secondary infections include:

Staphylococcus aureus skin colonization following a wound, which can progress to cellulitis or abscess formation.
Clostridium tetani spores introduced via contaminated puncture wounds, resulting in tetanus if immunization status is inadequate.
Leptospira interrogans exposure through urine‑contaminated water or food, potentially causing leptospirosis that may evolve into renal or hepatic failure.
Hantavirus inhalation of aerosolized rodent droppings, which can trigger hantavirus pulmonary syndrome after an initial respiratory irritation.

Risk factors that increase the likelihood of secondary infection are:

Delayed wound cleaning or improper disinfection.
Lack of tetanus booster within the past ten years.
Immunocompromised condition or chronic diseases that impair healing.
Presence of rodent infestations in residential or occupational settings, raising environmental load of pathogens.

Preventive measures focus on immediate wound management, routine vaccination, and rigorous environmental control. Prompt medical evaluation after any rat‑related injury reduces the chance that an initial infection will be complicated by additional microbial threats.

Contamination of Food and Water

Droppings and Urine

Rat excreta constitute a primary source of microbial contamination in residential and commercial settings. Droppings and urine deposit pathogens on surfaces, in food supplies, and in ventilation systems, creating direct exposure routes for occupants.

Leptospira spp. – bacteria causing leptospirosis, transmitted through contact with urine-contaminated water or soil.
Hantavirus – virus responsible for hemorrhagic fever with renal syndrome, aerosolized from dried droppings and urine particles.
Salmonella and Streptobacillus – bacteria that can be ingested via contaminated food or surfaces, leading to gastrointestinal illness and rat‑bite fever.
Coxiella burnetii – agent of Q fever, spread by inhalation of dried excreta.

Excreta also introduce allergens that trigger respiratory symptoms, including asthma and hypersensitivity pneumonitis. Accumulated droppings release particulate matter that irritates mucous membranes, while urine contributes ammonia vapors that degrade indoor air quality.

Mitigation requires routine sanitation, sealing entry points, and employing integrated pest management. Protective equipment, such as gloves and respirators, should be used during cleanup to prevent inhalation and dermal contact. Disinfection with EPA‑registered agents effectively reduces microbial load on surfaces after removal of all visible waste.

Hair and Saliva

Rats shed hair that can trigger allergic responses in susceptible individuals. The microscopic particles attach to clothing, bedding, and air‑conditioning filters, creating a pathway for inhalation and skin contact. Repeated exposure may lead to:

Seasonal‑type rhinitis
Asthmatic exacerbations
Contact dermatitis

Rat saliva contains a complex microbial load. When a rat bites or scratches, saliva is transferred directly into the wound, introducing pathogens that can cause serious infections. Documented risks include:

Streptobacillus moniliformis – cause of rat‑bite fever, presenting with fever, rash, and joint pain
Hantavirus – can be spread through saliva droplets, leading to hemorrhagic fever with renal syndrome
Leptospira spp. – transmitted via contaminated saliva, resulting in leptospirosis with renal and hepatic involvement

Both hair and saliva act as vectors for disease agents, making direct or indirect contact with rats a legitimate health concern. Preventive measures focus on rodent control, protective clothing, and prompt wound care after any bite or scratch.

Psychological Impact of Rat Infestations

Stress and Anxiety

Rats can trigger measurable stress responses in humans through direct and indirect mechanisms. Direct contact with rodents during infestations often leads to heightened physiological arousal, reflected by increased heart rate and cortisol levels. Indirect exposure, such as visual sightings of rats in residential or occupational settings, activates threat perception pathways, producing anxiety that persists beyond the immediate encounter.

Key pathways linking rat presence to human stress and anxiety include:

Disease vectors – pathogens carried by rats (e.g., hantavirus, leptospirosis) generate fear of infection, amplifying anticipatory anxiety.
Noise and movement – scurrying sounds and sudden appearances produce startle reactions, reinforcing hypervigilance.
Sanitation concerns – contamination of food and surfaces creates perceived loss of control, a core component of chronic stress.
Psychological association – cultural depictions of rats as pests reinforce negative emotional conditioning, sustaining apprehension.

Mitigation strategies that reduce these stressors involve integrated pest management, environmental sanitation, and public education on realistic risk levels. Consistent application of these measures lowers exposure frequency, thereby diminishing the physiological and psychological burden associated with rat encounters.

Fear and Phobias

Rats evoke a specific aversion known as musophobia, affecting a measurable segment of the population. Surveys indicate that 5‑10 % of adults report intense fear of rodents, with higher prevalence in urban environments where encounters are frequent.

The fear is often disproportionate to the actual health hazards rats present. Documented risks include:

Transmission of leptospirosis, hantavirus, and salmonella through contaminated urine, feces, or saliva.
Bites that may introduce bacterial infections such as Staphylococcus or Streptococcus.
Allergic reactions to rodent dander and droppings, leading to respiratory irritation or asthma exacerbation.

Epidemiological records show approximately 2‑3 rat‑bite incidents per 100 000 people annually in developed nations, with infection rates below 5 % of those cases. Disease outbreaks linked to rodent infestations remain rare when sanitation standards are maintained.

Psychologically, musophobia triggers autonomic responses—elevated heart rate, sweating, and avoidance of spaces where rats may appear. Persistent exposure can reinforce avoidance behavior, limiting access to housing or workplaces with known rodent activity. Evidence‑based interventions include systematic desensitization, cognitive‑behavioral therapy, and controlled exposure to reduce symptom severity.

Typical manifestations of rat‑related phobia are:

Immediate panic upon sight or sound of a rat.
Persistent dread in environments where rats might be present.
Physical symptoms such as trembling, shortness of breath, or nausea.
Disruption of daily activities to avoid perceived risk areas.

Understanding the distinction between rational health concerns and exaggerated fear enables targeted public‑health measures and effective therapeutic approaches.

Sleep Disturbances

Rats can interfere with human sleep through several direct and indirect pathways. Their nocturnal activity aligns with typical bedtime hours, creating conditions that disturb rest.

Audible noise from gnawing, scurrying, or vocalizations.
Vibrations transmitted through walls and floors.
Odor emission from urine, feces, and secretions.
Exposure to pathogens carried by rodents, prompting immune responses that disrupt sleep architecture.
Psychological stress induced by awareness of infestation, leading to heightened arousal and difficulty falling asleep.

Persistent sleep fragmentation reduces total sleep time and impairs deep‑sleep stages. Consequences include diminished cognitive performance, weakened immune function, and increased risk of cardiovascular events.

Effective mitigation relies on integrated pest management: sealing entry points, maintaining cleanliness, setting traps or bait stations, and monitoring activity with detection devices. Prompt intervention restores a sleep‑conducive environment and reduces health risks associated with rodent‑related sleep disturbances.

Prevention and Control Measures

Rodent-Proofing Homes

Rats can transmit pathogens, gnaw electrical wiring, and contaminate food, creating direct threats to human health and property. Preventing these risks begins with sealing a residence against entry.

Inspect the building envelope for gaps larger than ¼ inch; repair cracks, holes, and openings around pipes, vents, and utility lines.
Install metal flashing or copper mesh on foundation walls and under doors to block chewing.
Fit tight‑fitting door sweeps and weatherstripping on all exterior doors and windows.
Replace damaged screens and ensure attic vents have rodent‑proof covers.
Store food in sealed containers; keep countertops and floors free of crumbs.
Maintain landscaping: trim tree branches away from the roof, remove debris, and keep grass short to reduce shelter.

Regular maintenance sustains protection. Conduct quarterly visual checks for new gaps, droppings, or gnaw marks. Replace worn seals promptly. Set up monitoring devices, such as snap traps or electronic detectors, in high‑risk zones to confirm the absence of activity.

A fortified home eliminates common pathways for rats, reducing disease exposure, electrical hazards, and structural damage. Consistent application of these measures preserves safety and minimizes the need for reactive pest control.

Sanitation Practices

Sanitation directly influences the likelihood of rat‑borne hazards to people. Poor waste disposal provides food and shelter, encouraging rodent populations to thrive near residential and commercial spaces. Effective sanitation interrupts this cycle by removing resources that attract rats and by reducing opportunities for disease transmission.

Key sanitation measures include:

Securely sealed trash containers with tight‑fitting lids; empty them regularly to prevent overflow.
Prompt removal of food waste and leftover organic matter from kitchens, dining areas, and outdoor sites.
Routine cleaning of floors, countertops, and equipment to eliminate crumbs and spills that serve as rodent food sources.
Maintenance of drainage systems to avoid standing water and damp conditions that support rodent nesting.
Regular inspection and repair of building exteriors, sealing cracks, gaps, and utility entry points that allow rodent ingress.

Implementing these practices lowers rodent density, limits contact with contaminated surfaces, and reduces the incidence of illnesses such as leptospirosis, hantavirus, and salmonellosis. Consistent adherence to strict sanitation protocols is a primary defense against rat‑related health risks.

Professional Pest Control

Rats present a measurable threat to public health. They transmit pathogens such as Leptospira, hantavirus, and Salmonella, which can cause severe illness after ingestion of contaminated food or contact with urine and droppings. Bites may introduce bacterial infections, while allergic reactions to rodent dander affect susceptible individuals. Structural damage results from gnawing on wiring, insulation, and building materials, increasing fire risk and compromising integrity.

Professional pest control addresses these risks through a systematic process. Practitioners begin with a thorough inspection to locate entry points, nesting sites, and activity signs. Exclusion measures seal gaps, repair vents, and reinforce doors to prevent ingress. Sanitation protocols eliminate food and water sources that sustain populations. Trapping and baiting reduce existing rodents, using devices selected for efficacy and safety. Chemical applications follow regulatory guidelines, targeting infestations while minimizing non‑target exposure. Ongoing monitoring verifies control success and detects re‑infestation early.

Integrating these actions forms an effective management strategy that reduces the likelihood of human exposure to rodent‑borne hazards and mitigates property damage.

Specific Vulnerable Populations

Children

Rats pose several health threats to children, whose developing immune systems and frequent contact with the floor increase vulnerability. Direct bites can cause tissue damage and introduce bacteria such as Staphylococcus and Streptococcus, leading to wound infections that may require medical treatment. Indirect exposure occurs through rat‑borne pathogens; the most common include:

Leptospira spp. – transmitted via urine, can cause fever, kidney damage, and meningitis.
Hantavirus – spread by inhalation of aerosolized droppings, results in severe respiratory illness.
Salmonella – contaminates surfaces and food, produces gastrointestinal distress and dehydration.
Rat‑associated parasites – fleas and mites may bite children, causing itching, allergic reactions, or secondary infections.

Children often play in environments where rats hide, such as basements, attics, and outdoor play areas. Their propensity to place objects in the mouth raises the risk of ingesting contaminated material. Additionally, rat droppings and urine can trigger asthma attacks and allergic sensitization, especially in children with pre‑existing respiratory conditions.

Effective mitigation requires a combination of environmental control and education:

Seal entry points, repair damaged screens, and maintain clean, clutter‑free spaces to deter nesting.
Store food in sealed containers; promptly clean up spills and refuse.
Conduct regular inspections for signs of infestation—droppings, gnaw marks, or burrows.
Teach children to avoid handling rodents and to report sightings to adults.
Engage professional pest‑management services for confirmed infestations, ensuring safe use of rodenticides around children.

By addressing both direct and indirect exposure routes, caregivers can substantially reduce the likelihood of rat‑related health incidents in children.

Elderly Individuals

Rats present several health risks that disproportionately affect older adults. Their small size and nocturnal habits increase the likelihood of unnoticed contact, while age‑related physiological changes heighten susceptibility to infection and injury.

Disease transmission – Rats carry pathogens such as Leptospira, hantavirus, and salmonella. Elderly individuals often have weakened immune systems, making infections more severe and recovery slower.
Bite injuries – Dental problems and reduced tactile sensitivity raise the chance of accidental bites. Rat bites can introduce bacterial infections that require prompt medical treatment.
Allergic reactions – Exposure to rat urine, droppings, and dander can trigger respiratory allergies and asthma exacerbations, conditions more prevalent in seniors with chronic lung disease.
Environmental contamination – Rats contaminate food stores and surfaces with feces and urine, creating a vector for food‑borne illness. Older adults may have limited mobility, reducing their ability to maintain rigorous sanitation.
Fall risk – Sudden rat movement can startle elderly persons, causing loss of balance and falls, especially in cluttered living spaces.

Preventive measures include sealing entry points, maintaining clean storage areas, using traps or professional pest control, and regular health monitoring for signs of infection or allergy. Early detection and prompt response reduce the likelihood of serious complications.

Immunocompromised Individuals

Rats carry a wide range of pathogens that present heightened danger to individuals with weakened immune systems. Exposure can lead to severe infections, prolonged illness, and, in some cases, fatal outcomes.

Leptospira spp. – causes leptospirosis; symptoms range from fever to renal failure.
Salmonella enterica – produces salmonellosis; may result in septicemia in compromised hosts.
Hantavirus – triggers hemorrhagic fever with renal syndrome; mortality rates increase with immune deficiency.
Lymphocytic choriomeningitis virus – induces meningitis; immunosuppressed patients experience prolonged neurological deficits.
Streptobacillus moniliformis – responsible for rat‑bite fever; can progress to endocarditis without adequate immunity.
Parasites (e.g., Hymenolepis nana, Toxoplasma gondii) – may cause disseminated disease when host defenses are insufficient.

Transmission occurs through contaminated food, water, bedding, or direct bites and scratches. Aerosolized urine or droppings can introduce hantavirus and leptospira into the respiratory tract. Indirect contact, such as handling surfaces tainted by rodent excreta, also poses risk.

Control strategies focus on eliminating rodent access, maintaining strict sanitation, and using protective equipment when contact is unavoidable. Measures include sealing entry points, employing bait stations, conducting regular inspections, and wearing gloves and masks during cleaning. Immunocompromised patients should avoid environments with known rodent infestations and receive vaccinations where applicable (e.g., hepatitis A, tetanus).

Overall, the combination of pathogen diversity, efficient transmission pathways, and reduced host defenses makes rat‑related hazards a serious concern for those with compromised immunity. Effective pest management and personal protective practices are essential to mitigate these risks.