Western Equine Encephalomyelitis (WEE)

Western Equine Encephalomyelitis is a viral disease affecting the central nervous system of horses, causing inflammation of the brain and spinal cord that can result in severe neurological dysfunction and death. This mosquito-transmitted illness is caused by an alphavirus belonging to the Togaviridae family and has historically been an important cause of equine mortality in western and central regions of North America. Also known colloquially as sleeping sickness due to the profound depression and stupor exhibited by affected horses, WEE represents a significant though now relatively uncommon threat to unvaccinated equine populations.

Western Equine Encephalomyelitis primarily occurs in the western two-thirds of North America, with peak activity during summer months when mosquito vector populations are most abundant. The disease affects all breeds of horses equally, with susceptibility determined by vaccination status and immune response rather than genetic factors. While the incidence of clinical WEE has declined dramatically since widespread vaccination became standard practice, the virus continues to circulate in endemic areas through a cycle involving mosquitoes and wild birds, maintaining the potential for equine outbreaks when vaccination coverage lapses.

The impact of Western Equine Encephalomyelitis on affected horses ranges from mild illness with full recovery to fatal encephalitis. Mortality rates historically ranged from 20 to 50 percent in horses developing clinical neurological disease, with higher rates observed in young horses and those with severe brain involvement. Horses that survive often require prolonged recovery periods, and some retain permanent neurological deficits that limit their usefulness for riding or athletic performance. The economic impact includes both direct losses and the ongoing cost of preventive vaccination throughout the North American horse population.

Western Equine Encephalomyelitis is highly preventable through vaccination, which remains the cornerstone of disease control. Effective killed virus vaccines are widely available, typically combined with Eastern Equine Encephalomyelitis and Venezuelan Equine Encephalomyelitis vaccines in multivalent formulations. Maintaining current vaccination status represents the single most important step horse owners can take to protect against this potentially devastating infection. Combined with mosquito control measures, vaccination has transformed WEE from a common cause of equine mortality to an uncommon clinical occurrence.

Western Equine Encephalomyelitis is caused by infection with the Western equine encephalomyelitis virus, an alphavirus belonging to the Togaviridae family closely related to Eastern and Venezuelan equine encephalomyelitis viruses. The virus is maintained in nature through a complex enzootic cycle involving mosquito vectors and wild bird reservoir hosts, particularly passerine species such as sparrows, finches, and blackbirds. Horses become infected when bitten by mosquitoes that have previously fed on viremic birds, serving as incidental dead-end hosts that develop insufficient viremia to efficiently infect additional feeding mosquitoes.

There is no breed predisposition to Western Equine Encephalomyelitis, as all horses are equally susceptible to infection regardless of genetics or breeding. Quarter Horses, Thoroughbreds, Arabians, Warmbloods, draft breeds, ponies, donkeys, and mules all develop comparable disease when exposed to infected mosquitoes. However, age may influence disease manifestation, with foals and young horses potentially experiencing more severe neurological involvement than adult animals. Individual variation in immune response affects disease expression, with some horses experiencing subclinical infection while others develop severe or fatal encephalomyelitis.

Environmental and management factors significantly influence WEE transmission dynamics and equine exposure risk. The disease occurs seasonally, corresponding with mosquito activity from late spring through early fall, with peak incidence typically in July and August. Geographic distribution centers on the Great Plains, Rocky Mountain region, and Pacific states, though cases can occur throughout western North America where competent vectors and reservoir hosts coexist. Horses maintained in areas with abundant mosquito breeding habitat, particularly near irrigated agricultural lands, wetlands, or standing water sources, face elevated exposure risk. Climate conditions supporting mosquito populations, including warm temperatures and adequate moisture, enhance transmission potential.

Risk factors for developing clinical Western Equine Encephalomyelitis include vaccination status, age, geographic location, and seasonal timing. Unvaccinated horses face dramatically higher risk of clinical disease compared to appropriately immunized animals. Young horses under two years of age may experience more severe neurological manifestations. Horses in endemic regions of western North America during summer months encounter peak exposure periods. Management factors including outdoor housing without mosquito protection, proximity to mosquito breeding sites, and absence of vector control measures increase infection likelihood.

The pathophysiology of Western Equine Encephalomyelitis begins with viral inoculation during the bite of an infected mosquito, followed by initial replication in regional tissues. Viremia develops, allowing systemic distribution of the virus. In horses that develop neurological disease, the virus crosses the blood-brain barrier and infects neurons in the brain and spinal cord. This neuroinvasion triggers inflammatory responses causing neuronal damage and death, producing the clinical syndrome of encephalomyelitis. The incubation period from mosquito bite to symptom onset typically ranges from five to fourteen days, during which the virus replicates and spreads before nervous system invasion occurs.

Early warning signs of Western Equine Encephalomyelitis often begin subtly, as horses instinctively mask signs of illness as prey animals. Initial symptoms may include mild depression, slight reduction in appetite, and decreased interaction with herd mates or handlers. Owners might notice their horse appears quieter than usual, stands apart from companions, or shows diminished enthusiasm during feeding times. A low-grade fever often develops during this prodromal phase, typically ranging from 102 to 104 degrees Fahrenheit. Careful observation may reveal subtle stiffness or hesitation in movement before more obvious neurological signs become apparent.

As the disease progresses over the following one to five days, more definitive neurological symptoms emerge. The characteristic profound depression that gave rise to the term sleeping sickness becomes apparent, with affected horses standing with lowered heads showing little interest in surroundings or stimuli. Progressive incoordination affecting all four limbs develops, with horses demonstrating swaying gait, stumbling, and difficulty executing turns. Weakness, often more pronounced in the hindquarters initially, causes difficulty navigating inclines and unstable backing. Hypersensitivity to touch or sound may alternate with periods of obtundation.

Behavioral changes become increasingly pronounced as brain involvement progresses. Affected horses may exhibit wandering or aimless walking, circling in one direction, or compulsive movement along fencelines. Some horses develop apparent blindness, failing to respond to visual threats or navigate obstacles appropriately. Head pressing against walls, posts, or other objects represents a concerning sign of increased intracranial pressure. Irritability or aggression may alternate with profound stupor. Changes in water intake patterns and abnormal eating behaviors often accompany neurological deterioration.

Physical signs of advancing Western Equine Encephalomyelitis include progressive ataxia and weakness affecting all four limbs with characteristic hindquarter predominance. Facial paralysis causing drooping lips, asymmetric facial features, or difficulty swallowing may develop as cranial nerves become affected. Muscle fasciculations, particularly visible around the face and shoulders, often occur. Some horses develop abnormal head position, carrying the head low or to one side. Inability to close eyelids properly leads to corneal exposure and potential ulceration. Teeth grinding suggests pain or neurological dysfunction. Progressive muscle wasting becomes apparent in prolonged cases.

Symptom progression in severe cases leads to recumbency and inability to rise, typically occurring within several days of neurological sign onset. Recumbent horses often make repeated unsuccessful attempts to stand, thrashing in ways that risk self-injury. Paddling movements of the limbs may occur. Seizure activity develops in some cases, further complicating management and prognosis. Terminal cases may lapse into coma before death. The overall mortality rate in clinical cases historically approaches 20 to 50 percent, with higher rates in foals and horses with rapid progression to recumbency.

Emergency symptoms requiring immediate veterinary intervention include any combination of fever with neurological abnormalities, sudden onset of severe depression or disorientation, progressive weakness or incoordination, inability to stand, seizure activity, head pressing, or unexplained aggressive behavior. Any unvaccinated horse in an endemic area developing neurological signs during summer months should receive immediate veterinary evaluation for potential WEE. Early recognition and aggressive supportive care offer the best chance for survival and complete recovery in horses that will survive this infection.

Physical examination of horses suspected of having Western Equine Encephalomyelitis focuses on comprehensive neurological assessment combined with evaluation of vital parameters. The veterinarian will note elevated body temperature, heart rate, and respiratory rate consistent with systemic infection and stress. Neurological examination systematically evaluates mental status, ranging from depression to stupor, cranial nerve function including facial symmetry and pupil responses, gait and coordination, postural reactions, and spinal reflexes. Documentation of specific deficits provides baseline information for monitoring disease progression and treatment response. General physical examination assesses hydration status, body condition, and concurrent problems that might complicate treatment.

Diagnostic testing for Western Equine Encephalomyelitis employs several laboratory approaches to confirm infection and differentiate from other neurological diseases. Serology testing provides the primary diagnostic method, with IgM capture ELISA detecting antibodies specific to recent WEE virus infection. IgM antibodies indicate active or recent infection, while IgG antibodies may reflect current infection or previous exposure through natural infection or vaccination. Paired serum samples collected two to three weeks apart demonstrating rising titers confirm active infection. Cerebrospinal fluid analysis typically shows elevated protein and white blood cell counts consistent with viral encephalitis. Polymerase chain reaction testing can detect viral genetic material in blood or cerebrospinal fluid, though sensitivity varies with timing of sample collection.

Advanced diagnostic procedures may support diagnosis and assess disease severity. Complete blood count may show nonspecific changes including variable leukocyte counts and mild anemia in prolonged cases. Serum chemistry evaluates metabolic status and organ function. Cerebrospinal fluid collection through atlantooccipital or lumbosacral puncture requires specialized technique but provides valuable information confirming central nervous system inflammation. Virus isolation from blood or nervous tissue is possible but technically demanding and rarely performed clinically. In fatal cases, postmortem examination with histopathology of brain and spinal cord tissue demonstrates characteristic viral encephalitis lesions, and immunohistochemistry or polymerase chain reaction confirms the specific viral cause.

Differential diagnosis for horses presenting with fever and neurological signs includes other causes of equine encephalomyelitis requiring differentiation. Eastern Equine Encephalomyelitis produces similar clinical presentation but with generally higher mortality rates. Venezuelan Equine Encephalomyelitis occurs in overlapping regions and requires serological differentiation. West Nile Virus causes comparable neurological disease and has become more common than WEE in recent decades. Rabies must always be considered given its invariably fatal nature and zoonotic potential. Equine protozoal myeloencephalitis causes progressive neurological deficits, typically with more gradual onset and asymmetric presentation. Equine herpesvirus-1 myeloencephalopathy produces acute neurological disease often associated with respiratory illness or abortion. Hepatic encephalopathy, botulism, toxin exposure, and trauma require differentiation through appropriate testing.

Emergency treatment for horses with Western Equine Encephalomyelitis centers on immediate stabilization and initiation of intensive supportive care, as no specific antiviral medications exist for this disease. Upon recognition of neurological symptoms compatible with WEE, affected horses should be moved to safe environments minimizing injury risk from falls or collapse. Padded stalls with deep bedding provide protection for horses at risk of recumbency. Intravenous fluid therapy is established to maintain hydration, support circulation, and provide medication access. Anti-inflammatory therapy, including flunixin meglumine for its antipyretic and analgesic properties, is initiated promptly. Corticosteroids such as dexamethasone may be administered to reduce brain inflammation.

Medical management continues with medications targeting specific symptoms and potential complications. Dimethyl sulfoxide (DMSO) is frequently administered intravenously for its purported anti-inflammatory and antioxidant properties within the central nervous system. Vitamin E supplementation supports antioxidant defenses. Anticonvulsant medications including diazepam or phenobarbital are indicated for horses experiencing seizure activity and must be carefully titrated to control seizures while maintaining adequate mentation. Gastroprotective medications prevent stress ulcers common in critically ill horses. Antimicrobial therapy addresses secondary bacterial infections, particularly aspiration pneumonia developing in horses with swallowing dysfunction.

Surgical intervention is not directly applicable to Western Equine Encephalomyelitis treatment, as the disease process involves viral infection of the nervous system rather than surgically correctable conditions. However, procedural interventions support patient management. Placement of indwelling intravenous catheters facilitates ongoing fluid and medication administration. Nasogastric tubes provide nutritional support for horses unable to eat normally. Urinary catheterization becomes necessary in horses with bladder dysfunction. Severely affected recumbent horses may benefit from sling support systems in facilities equipped for intensive care, though prognosis for horses requiring sling support is generally guarded.

Supportive care extends to meticulous nursing management essential for critically ill horses. Recumbent animals require repositioning every two to four hours to prevent pressure sores, muscle damage, and nerve compression. Deep bedding with sand, shavings, or specialized padding protects vulnerable areas including points of hip, shoulder, and fetlocks. Passive range of motion exercises maintain joint flexibility. Horses unable to drink normally require fluid administration through nasogastric tube or continued intravenous support. Nutritional support maintains caloric intake through enteral feeding. Eye lubrication protects corneas in horses with incomplete eyelid closure. Environmental management maintains quiet surroundings with appropriate temperature control to reduce stress.

Rehabilitation and return to work for horses surviving Western Equine Encephalomyelitis varies based on residual neurological deficits. Horses demonstrating improving neurological function benefit from graduated physical therapy including assisted standing, controlled walking, and progressive exercise as strength and coordination return. Recovery periods extending from weeks to months are common, with some horses requiring six to twelve months to reach maximum improvement. Return to athletic use should be gradual and guided by thorough neurological evaluation confirming adequate recovery of coordination, strength, and proprioception for intended activities.

Treatment decision factors include disease severity, rate of progression, response to initial therapy, and resources available for intensive care. Horses presenting with mild to moderate signs that stabilize or improve with initial treatment carry more favorable prognoses. Rapid progression to severe neurological dysfunction or recumbency within forty-eight hours suggests severe brain involvement with guarded prognosis. Age influences outcomes, with foals facing higher mortality than adult horses. Economic considerations and the intensive nature of required care influence treatment decisions. Euthanasia may represent the most humane option for severely affected horses with poor prognosis or developing complications precluding quality survival.

Recovery timeline for horses surviving Western Equine Encephalomyelitis varies considerably based on initial disease severity and extent of neurological damage. Horses with mild disease that never became recumbent may show substantial improvement within one to two weeks and return to baseline function within one to two months. Moderate cases typically require several weeks to months of gradual improvement before reaching their recovery plateau. Severely affected horses that became recumbent face prolonged recovery periods often extending six to twelve months, with improvement potentially continuing throughout this extended timeframe. Maximum recovery may not be achieved until twelve to eighteen months following acute illness.

Post-treatment care and monitoring requirements are intensive during the recovery phase. Veterinary reexamination should occur regularly to assess neurological status and document improvement trajectory. Monitoring includes observation for complications such as secondary infections, muscle wasting from disuse, or joint problems developing from abnormal movement patterns during recovery. Nutritional support continues until normal eating and drinking behaviors are fully restored. Exercise should progress gradually based on neurological function, beginning with hand walking in controlled environments and advancing to turnout and ridden work only as coordination and strength permit. Regular hoof care maintains foot health, which becomes especially important in horses with altered gait during recovery.

Prognosis factors influencing recovery and long-term outcome include age, disease severity, rapidity of progression, and response to early treatment. Adult horses generally carry better prognoses than foals, which historically experience higher mortality rates. Horses that remained ambulatory throughout their illness have substantially better outcomes than those requiring recumbent care. Early aggressive supportive care before development of severe neurological signs improves both survival and completeness of recovery. Individual variation in immune response and pre-existing health status influences outcome. Progressive improvement within the first week of treatment typically predicts continued recovery, while early plateau or deterioration suggests poorer prognosis.

Long-term soundness outlook for Western Equine Encephalomyelitis survivors ranges from complete recovery to permanent deficits precluding previous use. Among horses surviving the acute illness, approximately half recover completely without detectable long-term effects, returning to previous activities as riding horses, breeding animals, or competitive athletes. The remaining survivors retain residual neurological deficits of varying severity. Mild residual signs such as subtle gait abnormalities may not preclude intended use but might be noticeable during careful examination. More significant deficits including persistent weakness, incoordination, or behavioral changes may necessitate retirement or repurposing to less demanding activities appropriate for the individual horse's functional capacity.

Management practices for preventing Western Equine Encephalomyelitis center on maintaining appropriate vaccination protocols and reducing mosquito exposure. Vaccination represents the cornerstone of prevention, providing highly effective protection against clinical disease. Mosquito control measures complement vaccination by reducing exposure to infected vectors. Elimination of standing water sources removes mosquito breeding habitat, including emptying water tanks weekly, maintaining proper drainage, and addressing areas where water accumulates. Treatment of unavoidable water sources with mosquito larvicides reduces local vector populations. Application of equine-approved insect repellents containing permethrin, pyrethrins, or other effective compounds provides additional protection during outdoor exposure.

Nutritional prevention strategies support immune function to optimize vaccine response and general disease resistance. Well-balanced feeding programs providing adequate protein, vitamins, and minerals support robust immune responses to vaccination. Ensuring horses receive appropriate selenium, vitamin E, and other antioxidants supports immune cell function and overall health. Avoiding nutritional deficiencies that might compromise immunity is particularly important as vaccination approaches. While nutrition cannot directly prevent WEE infection, optimal nutritional status supports the protective immune response that vaccination aims to stimulate and may influence disease severity if breakthrough infection occurs despite vaccination.

Exercise and conditioning considerations for WEE prevention relate primarily to general health maintenance and stress management. Regular, appropriate exercise supports overall health and immune function. Avoiding excessive stress from overtraining, which can temporarily suppress immune responses, is prudent particularly around vaccination times. Maintaining appropriate body condition supports immune competence. Competition and travel stress may warrant timing vaccination to allow adequate immune response development before exposure risk increases. Exercise schedules may require modification during peak mosquito season to minimize outdoor exposure during dawn and dusk hours when vector activity peaks.

Environmental factors significantly influence WEE risk and should be addressed in comprehensive prevention planning. Geographic location within western and central North America determines baseline risk. Proximity to wetlands, irrigated agricultural land, or other mosquito breeding habitat increases exposure potential. Pasture selection should favor well-drained areas when options exist. Turnout scheduling should account for daily mosquito activity patterns, with horses brought indoors during dawn and dusk when Culex mosquitoes are most active. Screened facilities provide protection for horses during high-risk periods. Bird populations, particularly wild passerines that serve as reservoir hosts, maintain the virus in endemic areas, making complete elimination impossible and vaccination essential.

Vaccination protocols form the cornerstone of Western Equine Encephalomyelitis prevention. Killed virus vaccines are widely available, typically combined with Eastern Equine Encephalomyelitis and Venezuelan Equine Encephalomyelitis vaccines in trivalent formulations, often with additional protection against West Nile Virus and tetanus. Initial vaccination requires a primary series of two doses administered three to four weeks apart. Annual boosters maintain immunity, with administration typically recommended in spring before mosquito season begins. Semi-annual vaccination may be warranted in high-risk areas or for horses with year-round exposure potential. Foals can begin vaccination at four to six months of age, with timing adjusted based on maternal antibody status and regional risk factors.

Daily management adjustments for horses in WEE-endemic regions require attention to mosquito avoidance and vaccination compliance. Routine barn activities should be scheduled to minimize outdoor exposure during peak mosquito activity periods, typically dawn and dusk when Culex mosquitoes are most active. Daily application of effective insect repellent protects horses requiring outdoor time during higher risk periods. Temperature monitoring provides early detection of fever that might indicate developing illness. Observation for subtle changes in behavior, coordination, or attitude enables prompt veterinary consultation for horses showing concerning signs. Water containers should be emptied and cleaned regularly to prevent mosquito breeding.

Housing and turnout considerations balance disease prevention with horse welfare. Ideal housing includes barns with screened windows and doors preventing mosquito entry while maintaining adequate ventilation. Ceiling fans improve air circulation and create airflow patterns discouraging mosquito presence. Stabling during dawn and dusk hours when vectors are most active provides the most critical protection without requiring complete indoor housing. Pasture selection should favor well-drained areas away from wetlands and standing water sources. Horses recovering from WEE require protected housing with safe, padded environments until neurological function has recovered sufficiently to prevent fall-related injuries during turnout.

Exercise modifications during peak WEE transmission season help balance fitness maintenance with disease prevention. Training schedules may require adjustment to avoid dawn and dusk exercise times when mosquito exposure risk peaks. Indoor arenas provide protection for maintaining training programs while minimizing outdoor exposure during high-risk periods. Trail riding and outdoor activities should include effective insect repellent application. Horses recovering from WEE require carefully graduated return-to-exercise programs designed around their individual neurological status, with advancement based on documented improvement in coordination, strength, and proprioception. Return to athletic performance should be guided by veterinary assessment confirming adequate recovery.

Monitoring and ongoing care protocols are essential for all horses during WEE transmission season. Vaccination records should be meticulously maintained to ensure timely annual or semi-annual boosters. Regular veterinary examinations provide opportunities for health assessment and vaccination updates. Body condition monitoring ensures nutritional needs are being met. Owners should be familiar with early signs of neurological disease, including subtle behavior changes, mild incoordination, and fever. Prompt reporting of concerning signs enables early intervention if infection occurs. Horses recovering from WEE require ongoing monitoring of neurological status, with regular veterinary assessments documenting recovery progress.

Quality of life and use considerations following WEE infection depend on recovery extent and residual deficits. Most horses recovering fully return to previous activity levels without restrictions, resuming careers as riding horses, breeding animals, or competitive athletes. Those retaining mild residual deficits may continue previous activities with awareness of subtle limitations. Horses with moderate residual incoordination or weakness may need repurposing from high-demand athletic activities to lower-level work or pleasure use. Severely affected survivors may be suitable only for light activity, breeding, or companion animal status depending on the nature and extent of permanent neurological damage. Regular veterinary reassessment helps determine appropriate activity levels as recovery progresses or limitations become apparent.

Western Equine Encephalomyelitis does not demonstrate breed-specific susceptibility, affecting all horses, ponies, donkeys, and mules equally when exposed to infected mosquitoes. Susceptibility to infection and clinical disease development is determined by vaccination status, individual immune response, and exposure level rather than genetics or breeding. Thoroughbreds, Quarter Horses, Arabians, Warmbloods, gaited breeds, draft breeds, ponies, and mules face identical infection risk under comparable exposure conditions. This absence of breed predilection emphasizes that vaccination represents a universal priority for all equine populations in endemic regions regardless of breed, value, or intended use.

Use and discipline considerations relate to exposure risk factors rather than breed characteristics. Horses maintained primarily outdoors face higher mosquito exposure than those kept in protected stabling. Working ranch horses, trail horses, and horses in pasture-based management systems may encounter greater vector contact than show horses maintained in screened facilities. Geographic location significantly influences risk, with horses in the Great Plains, Rocky Mountain region, and Pacific states facing higher exposure than those in other areas. Horses that travel may encounter varying transmission intensity in different locations. These risk factors apply regardless of breed, making management practices and vaccination the key determinants of protection.

Genetic testing and breeding recommendations are not applicable to Western Equine Encephalomyelitis since susceptibility is not genetically determined. No selective breeding can reduce disease risk, making vaccination the sole effective prevention approach. However, breeding operations in endemic regions should maintain comprehensive vaccination programs for all animals including stallions, mares, and young stock. Pregnant mares should be vaccinated according to veterinary guidance, typically receiving boosters four to six weeks before foaling to ensure high colostral antibody levels. Foals should begin active immunization at four to six months of age. The emphasis remains on universal vaccination rather than genetic considerations in breeding decisions.

Western Equine Encephalomyelitis commonly leads to secondary complications requiring additional treatment. Aspiration pneumonia develops in horses with pharyngeal dysfunction and swallowing difficulties, representing a significant cause of death in horses surviving initial neurological involvement. Pressure sores, muscle damage, and peripheral nerve injury affect recumbent horses despite best nursing care and may require prolonged management. Secondary bacterial infections of various body systems develop in immunocompromised, systemically ill animals. Gastric ulceration occurs commonly in stressed, critically ill horses requiring preventive or therapeutic medication. Corneal ulceration develops in horses with incomplete eyelid closure from facial nerve involvement. Weight loss and muscle wasting complicate recovery in horses with prolonged illness.

Conditions with similar symptoms requiring differentiation include other arboviral encephalitides that may produce nearly identical clinical presentations. Eastern Equine Encephalomyelitis causes similar neurological disease but with typically higher mortality rates, differentiated through specific serology. Venezuelan Equine Encephalomyelitis produces comparable encephalitis signs in regions where geographic ranges overlap. West Nile Virus infection causes similar neurological disease and has become more prevalent than WEE in recent decades. Rabies must always be considered given its invariably fatal nature and zoonotic potential, requiring exclusion in any horse with unexplained neurological disease. Equine protozoal myeloencephalitis produces progressive neurological deficits but typically with gradual onset and asymmetric presentation. Equine herpesvirus-1 myeloencephalopathy causes acute neurological disease often associated with respiratory signs or abortion. Botulism, hepatic encephalopathy, toxin exposure, and trauma require differentiation.

Potential complications of Western Equine Encephalomyelitis include permanent neurological damage affecting gait, strength, behavior, or cognitive function in surviving horses. Residual deficits range from subtle abnormalities noticeable only during careful examination to severe impairment precluding previous use. Behavioral changes including altered personality, increased fearfulness, or reduced trainability occasionally persist in survivors. Secondary complications during acute illness include aspiration pneumonia, corneal ulceration, joint stiffness from prolonged recumbency, and muscle atrophy requiring extended rehabilitation. Economic losses from treatment costs, prolonged recovery periods, potential career limitation, and mortality represent significant impacts of this preventable disease.