Grifulvin V

Dogs, cats, rodents, reptiles and birds can transmit numerous diseases. Some are localized infections resulting from bites, scratches or other skin contact. Occasionally, a minor scratch or bite can lead to more serious infection, such as cat-scratch disease. Under certain circumstances, serious gastrointestinal, respiratory or multisystem illness can develop. Accurate diagnosis and identification of the pet source are necessary to prevent further transmission.

Many infectious diseases in humans are acquired through direct contact with pets. Estimates are that over 40 million dogs and 30 million cats are kept as pets in the United States.(1 ) Added to this number of pets are millions of rodents, birds, reptiles and tropical fish. The potential for exposure to diseases caused by pets is enormous. Pet-related infections may be localized, resulting from obvious direct contact (such as bites or scratches), or they may cause systemic illness, which may not necessarily be attributed to animal contact.

Localized Infections

BITES AND SCRATCHES

The infection rate from animal bites and scratches varies according to the type of wound (puncture, laceration or scratch); the location of the bite; the interval between the injury and treatment, and the type of animal. For example, cat bites and scratches become infected more frequently than do dog bites, because cat bites usually result in deeper punctures.

The prospective management of animal bites is discussed in an AFP article by Goldstein and Richwald.(2 ) In addition to determining the rabies immunization status of the pet, the tetanus immunization status of the patient must also be determined because soil contamination of the wound may occur at the time of the bite. If tetanus immunization is not current, the patient should be vaccinated following a schedule as for any "dirty" wound.

For an infected wound, the choice of antibiotic depends on the bacteriology. The most common pathogens in infections from dog and cat bites are Pasteurella multocida, Staphylococcus aureus and Streptococcus species. R multocida is a small, bipolar-staining, gram-negative coccobacillus that is part of the nasopharyngeal flora of many domestic and wild animals. Cat bites or scratches are twice as likely as dog bites to be infected by this organism(3 ) (Figures 1 and 2). Pasteurella is especially likely to be the pathogen if cellulitis develops acutely, typically less than 24 hours after the bite or scratch. If the incubation period is longer, staphylococcal or streptococcal infection is more likely.

Mile penicillin is the preferred agent for P. multocida infection, it is inadequate for penicillin-resistant staphylococci. Therefore, unless wound bacteriology is known or pasteurella infection is strongly suspected, antimicrobial therapy should be started with a semisynthetic penicillin, such as dicloxacillin, 500 mg four times daily for five to seven days, or with cephalexin (Keflex), 500 mg four times daily for five to seven days. Alternatively, therapy may be initiated with amoxicillin/clavulanate potassium (Augmentin), 500 mg three times daily for five to seven days. In cases of staphylococcal infection, erythromycin is suitable for patients allergic to penicillin, but it is inadequate treatment for pasteurella infection. Tetracycline (500 mg four times daily for five to seven days) is an alternative for patients with pasteurella infection and penicillin allergy.

Cultures should always be obtained from infected bite wounds, and follow-up assessment of the wound after 24 and 48 hours is mandatory. Hospitalization is recommended for patients who appear septic, who are immunocompromised or who are at high risk of complications because they have prosthetic devices in place.

DERMATOPHYTOSES

Domestic cats and dogs can transmit dermatophytes, usually Microsporum canis but also Microsporum gypseum and Trichophyton mentagrophytes, which cause tinea capitis and ringworm.(4 ) Dermatophytosis develops following direct contact with an infected animal. This skin disease is especially common in children, but occurs in adults as well. The infection may not be obvious in the animal.

The spectrum of ringworm in humans and pets varies from subclinical colonization to an inflammatory scaly eruption (Figure 3) that spreads peripherally and causes localized alopecia. Many cases resolve spontaneously. Diagnosis is made by identifying hyphae in skin scrapings on a potassium hydroxide slide or by fungal culture.

Topical treatment with clotrimazole (Lotrimin, Mycelex) or miconazole (Monistat-Derm), twice daily for two to four weeks, is usually sufficient. Oral griseofulvin (Fulvicin, Grifulvin V, Grisactin, etc.) should be used when the lesions are extensive or when tinea capitis is present. The adult dosage is 500 mg twice daily for four weeks for skin infections and for six to eight weeks for scalp infections.

SCABIES

Scabies is caused by infection with the mite Sarcoptes scabiei. The subspecies that infects dogs (and rarely cats) can occasionally infect humans and cause intensely pruritic, papular, excoriated lesions.(5 ) Hypersensitivity to the mite is the primary cause of the illness. Burrows rarely occur, since the animal subspecies cannot complete its life cycle in the human host. This is in contrast to infection with the human variant.

Skin scrapings are negative in this form of scabies; thus, the diagnosis must be made on the basis of clinical appearance. Treatment is usually not necessary, but the carrier pet must have its infestation eliminated to prevent recurrent infections. Washing clothes and bedding with hot water and detergent usually clears the environment of mites and ova.

CUTANEOUS LARVA MIGRANS

Cutaneous larva migrans, or creeping eruption, is contracted from exposure to the fecal matter of cats and dogs infected with the intestinal nematode Ancylostoma braziliense.(6 ) Larvae hatch from the eggs eliminated in the feces of the infected pet. The larvae can survive for several days in warm, moist soil.

Most cases of cutaneous larva migrans occur in warm climates. The larvae burrow into exposed skin and migrate several millimeters daily, forming serpiginous tracts. The resulting tissue reaction causes intense pruritus. The larvae are unable to complete a life cycle in the human host and die after several weeks or months.

Because infection follows direct contact with contaminated soil, the feet or lower legs are most often affected. Diagnosis is made by clinical appearance. Treatment with thiabendazole (Mintezol), 25 mg per kg in one dose, usually results in immediate relief of itching. A repeat dose in several days may be given if necessary.

'SWIMMING POOL' GRANULOMA

"Swimming pool" granuloma and subcutaneous abscess can be caused by contact with tropical fish aquariums. The etiologic agent is Mycobacterium marinum, a photochrornagen. The lesions usually occur on the fingers or hands, often at the site of minor trauma. After several weeks of incubation, a papule appears and then gradually enlarges to a dark, suppurative lesion.

The infection often resolves following treatment with minocydine (Minocin), 100 mg twice daily for six to eight weeks. If the response is poor, prolonged therapy with ethambutol (Myambutol) and rifampin (Rifadin, Rimactane) may be useful.(7 )

SPOROTRICHOSIS

Sporotrichosis, a fungal infection, is primarily contracted from thorn pricks, although it can develop from exposure to spores attached to the fur of pets. Cutaneous sporotrichosis in cats can also cause human infection if the skin is punctured by a bite or scratch from an infected cat."

The initial lesion resembles swimming pool granuloma. Ascending suppurative lymphadenitis usually develops following the initial lesion Figure 4). Sporotrichosis is diagnosed by biopsy and culture.

Treatment consists of oral administration of a saturated solution of potassium iodide, ten drops three times daily after meals. The dosage is gradually increased to 40 drops three times daily, until the lesions resolve. Systemic Illness from Bites or Scratches

Systemic illnesses that can be contracted from different pets are summarized in Table 1. A few diseases may develop following an animal bite or scratch.

CAT-SCRATCH DISEASE

Febrile adenitis following scratches or bites by apparently healthy cats has been a recognized illness for several decades, but the etiologic agent, a small gram-regative bacillus, has only recently been identified.(9,10) Cat-scratch disease can also be acquired by an infected cat licking an open lesion.

With cat-scratch disease, an erythematous papule appears at the primary site of infection about ten days after a scratch (or any other form of exposure). In another ten days, regional adenopathy develops (Figure 5). Although adenopathy is always present, the primary papule may not develop in up to 50 percent of the patients. Malaise and fever may accompany the adenopathy, but laboratory tests are usually normal.

When a history of a recent cat scratch or bite is elicited, and other common causes of adenopathy can be eliminated, cat-scratch is likely The diagnosis can be made by the characteristic microscopic appearance of lymph nodes (i.e., granulomatous inflammation with or without stellate microabscesses) or by culture of the pus on brain-heart infusion agar at 30[.degrees.C]. A Warthin-Starry stain may reveal the organism in pus, while Gram stain will be negative. Intradermal skin testing has been used diagnostically, but the material for testing is not commercially available.

Needle aspiration of a large suppurative node may provide temporary relief, but incision and drainage should be avoided, since this intervention will lead to sinus tract formation. However, tangential needle aspiration of a lymph node will not result in sinus tract formation and can be used for diagnostic studies.

Cat-scratch disease usually regresses within about two months, without specific treatment. Rarely, neurologic sequelae, including spontaneously resolving encephalitis, may develop. In severe cases of cat-scratch disease, a trial of tetracyliine is warranted; the pathogen has shown in vitro sensitivity to tetracycline.

RAT-BITE FEVER

Rat-bite fever (formerly called Haverhill fever) is a generalized illness consisting of headache, myalgias and fever. It may develop within ten days of a rodent bite." Often, the primary bite has healed by the time symptoms are noted. A rash (petechial or morbilliform) and arthralgias or arthritis follow the onset of fever. The illness results from infection with Streptobacillus moniliformis, a gram-negative bacillus present in the nasopharynx of up to 50 percent of rats.

Diagnosis of rat-bite fever is made by culture of the organism from blood or joint fluid. If the infection is not treated, relapsing fever ensues over several months. Endocarditis, pericarditis or pneumonia may occur. Treatment consists of parenteral procaine peniciillin G, 600,000 u every 12 hours for seven days.

A spirochete Spirillum minor also can cause rat-bite fever. With this infection, an eschar develops at the site of the bite. The lesion subsequently becomes an ulcer, which recurs with each relapse and is accompanied by a violaceous rash. The incubation period for S. minor infection is slightly longer than that for streptobacillus infection, and joint symptoms are unusual. Diagnosis depends on identification of the organism in tissue or blood samples, using darkfield microscopy. Treatment with penicillin is effective. This form of rat-bite fever is rare in the United States.

DF-2

In immunosupprressed or splenectomized patients, dog bites have been responsible for infection with a fastidious gram-negative bacillus, identified as "dysgonic fermenting" (DF-2) organism (an organism that will not ferment carbohydrates in routine media).(12) The organism has been identified as part of the normal canine mouth flora.

Typically, infection leads to sepsis with disseminated intravascular coagulation within seven to 14 days of the dog bite. The usual signs of infection are not evident at the inoculation site. Because the outcome is often fatal, prophylactic penicillin should be considered in immunosuppressed or splenectomized patients who incur a dog bite.

Gastrointestinal Infections

The different etiologies of diarrhea in pet-related infections are summarized in Table2.

CAMPYLOBACTER

Campylobacter is a gram-negative, motile, curved, spiral microaerophilic rod that has long been identified in the gastrointestinal tract of domestic animals, including dogs and cats, simian primates, horses and chickens. The subspecies Campylobacter jejuni can cause enterocolitis in humans.(13) In humans, campylobacter infection is characterized by abdominal pain and cramps, fever, chills and diarrhea, which is frequently bloody. The incubation period is two to five days. The symptoms usually subside within a week, but abdominal pain may persist for several weeks and excretion of campylobacter organisms in the feces continues for four to five weeks. The disease is especially common in young children and adolescents.

Campylobacter infection produces symptoms similar to those caused by other invasive intestinal bacteria, such as Shigella and Salmonella, with abundant blood and leukocytes on fecal smear. It is actually more common than shigellosis or salmonellosis.

The organism appears to be transmitted in a manner similar to that of Salmonella and Giardia, primarily through water and food. However, puppies and cats with diarrhea have been shown to transmit the disease. The overall isolation rate in cats may be as high as 45 percent. Even apparently healthy cats may transmit the disease by means of fecal contamination.(14) Hamsters also may excrete the organism.(15)

Definitive diagnosis of campylobacter infection requires isolation of the organism with special blood agar cultures incubated at 42[.degrees.C] for three to four days. Gram stain of a fecal smear may demonstrate the organism in about half of infected patients.(16) The organism appears as a slender, gram-negative rod, shaped like a seagull, a curve or an equivalent sign (-).

Therapy depends on the severity of the illness. Since the disease is usually self-limited, fluid replacement alone is often sufficient in healthy patients. However, in a very young or debilitated patient, erythromycin, 25 to 50 mg per kg in three divided doses for seven to ten days, provides optimal treatment. As an alternative, tetracycline or ciprofloxacin (Cipro), 500 mg twice daily, may be used.

NONTYPHOIDAL SALMONELLA

Salmonellae are motile gram-negative rods; there are three major species: S. typhi (responsible for typhoid fever), S. choleraesuis and S. enteritidis. The latter includes over 1,500 serotypes. Various serotypes of this species cause gastrointestinal infections.

The incubation period following ingestion of S. enteritidis is six to 48 hours. Nausea and vomiting, fever, chills, abdominal cramps and tenderness, and diarrhea then develop. The diarrhea is usually watery and, occasionally, bloody. Stool specimens contain polymorphonuclear neutrophils and, occasionally, red blood cells. The diarrhea lasts up to one week, but organisms may be shed in the stool for up to three weeks. Colitis characterized by microabscesses and ulceration may develop. Diagnosis is by stool culture.

Except for S. typhi (which is species-specific for humans), the other Salmonella species have been isolated from most animals, including poultry, cats, dogs, mice, lizards, snakes and turtles. Salmonellosis is usually the result of ingestion of contaminated water or food, especially poultry and eggs. Pet chicks, ducklings and turtles, however, can be the source of infection also.

Pet turtles have accounted for 3 percent of outbreaks. Infections caused by turtles usually occur in children under ten years of age and generally result from direct handling of infected animals, combined with poor hand washing. Following restrictions on production and on interstate shipment of turtles, the number of cases of enterocolitis due to turtle-associated serotypes decreased by 77 percent from 1970 to 1976.(17)

Primary treatment of salmonellosis consists of fluid and electrolyte replacement. Antibiotics not only fail to shorten the duration of the illness but also may prolong the carrier state.

EDWARDSIELLA

Edwardsiella tarda, a gram-negative organism biochemically similar to Salmonella, is found in snakes, turtles and toads.(18) In humans, the organism may cause gastroenteritis that resembles salmonellosis. Turtle-to-human transmission of E. tarda has been reported to cause disease. The usual course is spontaneous remission without therapy.

PLESIOMONAS

Plesiomonas shigelloides (formerly Aeromonas shigelloides) is a gram-negative, facultatively anaerobic rod that causes progressive ulcerative stomatitis ("mouth rot disease") in snakes. Transmission to humans may occur, resulting in acute gastroenteritis with copious watery diarrhea.(19)

Diagnosis is made by stool culture. Therapy with trimethoprim/sulfamethoxazole (Bactrim, Septra) for five days results in cure. Tetracycline or chloramphenicol (Chloromycetin) is effective alternative therapy.

YERSINIA

Yersinia enterocolitica is a gram-negative organism with several dozen separate serotypes. Enterocolitis caused by this organism is characterized by abdominal pain, fever and diarrhea. Stool specimens contain polymorphonuclear neutrophils and, occasionally, blood. Diagnosis depends on culture of the organism from the stool.

Animal vectors are not considered to be the major source of infection, but transmission from dogs to humans has been demonstrated. (20) Uncomplicated enterocolitis is usually self-limited; thus, antimicrobial therapy is not necessary. However, debilitated patients should probably be treated with gentamicin or chloramphenicol.

DIPYLIDIASIS

Dogs and cats may harbor the tapeworm Dipylidium canium.(21) The flea or dog louse is an intermediate host. Ingestion of the intermediate host allows development of the adult worm in humans. The parasite is most commonly found in young children who play around pets and put contaminated toys into their mouths. Mild gastroenteritis with eosinophilia develops.

Diagnosis is made by the identification of proglottids (body segments) in the stool. Treatment with the anticestode drug niclosamide (Niclocide) is effective.

Respiratory Infections

PSITTACOSIS

Psittacosis was so named because it was originally thought to be associated only with psittacine birds (e.g., parrots, macaws and parakeets). It has since been associated with many species of birds, including turkeys, ducks, chickens, canaries and pigeons. Although the term ornithosis is sometimes used to describe the disease, psittacosis is preferred since the disease is caused by the chlamydial agent Chlamydia psittaci.(22)

In humans, exposure to the organism occurs through inhalation. After the organisms reach the lungs, the infection spreads hematogenously throughout the body; the organism is filtered out by the reticuloendothelial system. Incubation from the time of inhalation to the development of symptoms is seven to 14 days.

Psittacosis is expressed in a wide range of severity, from subclinical disease to fatal cases occasionally. Symptoms are nonspecific and consist of sore throat, anorexia, weakness, fever and chills, bradycardia, nonproductive cough and a very severe headache. Chest radiographs usually reveal a patchy infiltrate in the lower lobes (Figure 6). Hepatosplenomegaly is common and a faint macular rash often develops. The rash may be indistinguishable from the rose spots associated with typhoid fever. The combination of a nonproductive cough, a high fever, bradycardia, splenomegaly and severe headache strongly suggests the diagnosis of psittacosis.

Diagnosis of psittacosis can be made retrospectively by rising complement fixation antibody titers. Culture of the organism requires tissue culture or yolk sac of embryonated eggs and is not readily available. Thus, treatment is initiated on the basis of a clinical diagnosis, with antibody titers used for confirmation purposes.

Untreated, psittacosis lasts two to three weeks, but the infection can be fatal in up to 20 percent of patients. Treatment with tetracycline, 500 mg every six hours orally, produces a response within 24 to 72 hours; therapy must be continued for 14 days.

In birds, the disease can be passed during egg laying or nesting, and may be present immediately in newly hatched birds. The organisms are excreted in eye and nostril secretions and in feces. They are usually found on the bird's feathers and are readily aerosolized from dried feces or feathers. Even brief exposure to an area inhabited by an infected bird can result in infection.

Restrictions on importation of birds into the United States and the addition of chlortetracydine to bird feed have reduced the incidence of psittacosis, but the disease has not been totally eliminated in the United States.

DIROFLARIASIS

Canine heartworm, caused by Diroplaria immitis, is transmitted from dog-to-dog by transfer of circulating microfilaria through mosquito bites. If a human is bitten by an infected mosquito, the larva migrates to the heart, then dies and embolizes to the lung.(23) Granuloma formation around the dead worm produces a peripheral coin lesion in the lung. The nature of the lesion is usually identified only after thoracotomy.

More than half of infected patients are asymptomatic. In others, cough or chest pain may occur. Mild eosinophilia may also be occasionally noted. Surgical excision of the pulmonary lesion is curative as well as diagnostic. In endemic areas, dogs should be given prophylactic heartworm medication (diethylcarbamazine) to eliminate the possibility of human disease.

STREPTOCOCCAL PHARYNGITIS

Group A beta-hemolytic streptococcal infections of the pharynx are most commonly spread person-to-person. However, frequent reinfection or failure to eradicate the infection despite adequate therapy is cause to search for a carrier within the household or among social contacts. An unrecognized source of streptococcal infection may be the family dog or cat, which contracts the infection from a family member and then serves as a reservoir.(24) Pharyngeal cultures of the pet and eradication of the carrier state through a treatment plan with the veterinarian will eliminate the repetitive cycle of pharyngitis in the household.

Multisystem Illnesses

TOXOPLASMOSIS

Toxoplasma gondii is a protozoan found in all mammals, some birds and some reptiles. The organism exists in three forms: trophozoite, cyst and oocyst. The latter two are the infectious forms. The cyst can contain up to several thousand organisms. If contaminated meat is ingested, digestive enzymes free these organisms and infection occurs. Ten percent of lamb, 25 percent of pork and 1 percent of beef contain cysts, but heating meat to over 60[.degrees.C] (140[.degrees.F]) inactivates the cyst.

It is primarily through a complicated lifecycle in cats that transmission to humans occurs(25,26) (Figure 7). The oocyst, which is excreted only by members of the cat family, sporulates one to 21 days after excretion and can survive for months or even years in moist, warm soil. Ingestion of the oocyst may occur through direct fecal-oral contamination or by transmission of the oocyst to food by flies and cockroaches. Oocyst ingestion allows release of trophozoites in the gastrointestinal tract and dissemination throughout the body.

Toxoplasmosis epidemics can occur in children who ingest fecally contaminated soil and can even occur in adults who are casually exposed to infected cats. In the United States, serologic surveys reveal a 20 to 70 percent prevalence of antibody to the organism in adults, depending on geographic area.

In many cases, toxoplasmosis is asympmtomatic and self-limited, with lymphadenopathy the only clinical finding. In severe cases, patients develop fever, malaise, myalgias, headache, sore throat and hepatosplenomegaly clinically resembling infectious mononucleosis. Rarely, myocarditis, pericarditis, hepatitis, pneumonitis or meningoencephalitis may develop. The disease can be fulminant and fatal in the immunosuppressed patient. In healthy adults, the primary danger is to pregnant women. When primary infection occurs during pregnancy, even if it is asymptomatic, there is a 30 percent chance that the fetus will develop congenital toxoplasmosis. This form of the illness is associated with mental retardation, jaundice, thrombocytopenia, seizure, and impaired vision.

Diagnosis can be made serologically or by biopsy (Figures 8 and 9). The most widely used serologic test is the indirect fluorescent antibody test, which becomes positive in one to two weeks after

No treatment is required in healthy adults who manifest only adenopathy or a mononucleosis-like illness. Symptoms resolve over several weeks. Treatment of patients with fulminant disease or with localized ocular toxoplasmosis and treatment of congenitally infected infants involve a complicated course of pyrimethamine and sulfonamides. Treatment of pregnant women is more complex, because of the teratogenic potential of pyrimethamine.

Prevention of toxoplasmosis depends on careful hand washing after handling cat feces. Pregnant women should not clean cat litter boxes. If this cannot be avoided, disposable gloves should be worn. Adequate cooking will prevent disease from ingestion of contaminated lamb, pork or beef.

VISCERAL LARVA MIGRANS (TOXOCARIASIS)

Toxocara canis, a dog ascarid or roundworm, and Toxocara cati, the roundworm of cats, can complete their life cycle only in the animal host (Figure 10). However, the eggs are excreted in the animal's feces. If the eggs are ingested by humans, the larvae are released in the gastrointestinal tract, from where they migrate to the liver (Figure 11), lungs, kidney or brain. The larvae evoke a granulomatous response, and then become encysted. The cycle can progress no further in humans; and thus the infection is self-limited. During the migration and encysting process, however, a generalized illness may result, with fever, cough, wheezing and abdominal complaints. nomegaly is usually present and marked eosinophilia occurs.(27)

T canis eggs are excreted only by young puppies and adult female dogs within six months of parturition. After incubating in the soil for two to three weeks, the eggs become infectious and can remain so for months.

Diagnosis of toxocariasis is often made clinically. Since the worm cycle is not completed in humans, stool samples will not contain eggs. Diagnosis can be made through liver biopsy or by serologic testing. If the disease is asymptomatic or mild, treatment is not needed. For severe symptoms, treatment with thiabendazole (Mintezol) or diethylcarbamazine is effective. Steroids are often used to control the inflammatory response.

Most cases of toxocanasis occur in children under five years of age, an age group in which pica is common. Avoidance of the disease is accomplished by limiting contact of young children with new puppies, not allowing children to play in areas where dogs defecate and deworming household dogs soon after birth.

LEPTOSPIROSIS

Leptospirosis is an acute, generalized illness characterized by headache, myalgias, fever, abdominal pain and, sometimes, jaundice. It is caused by a spirochete of the genus Leptospira. The organism is found in many domestic and wild mammals and is excreted in the urine. The disease is spread to humans by way of contact with infected urine on abraded skin or mucous membranes. Worldwide, rats are responsible for most human disease, but in the United States dogs most frequently account for transmission to humans.(28) Icteric sclerae and diarrhea are frequent findings in infected dogs.

Vaccination of livestock and dogs has decreased the number of cases of leptospirosis in the United States. Only about 75 cases per year have been reported in recent decades. But even vaccinated, apparently healthy dogs can sometimes be infectious. (19) Leptospirosis is treated with doxycycline, 100 mg twice daily for seven days.

BRUCELLOSIS

Brucella is a small gram-negative coccobacillus that causes disease in goats (B. melitensis), cattle (B. abortus), pigs (B. suis) and dogs (B. canis). Beagles especially have a tendency to be infected. The organism is excreted in the urine. Infected animals may have abortions but otherwise appear healthy.

Although brucellosis most often occurs in farmers, veterinarians, meat packers or persons who ingest unpasteurized milk or cheese, infection occasionally follows contact with infected dogs.(30,31) Nonspecific symptoms such as fever, chills, malaise, weight loss, adenopathy and splenomegaly are characteristic.

Diagnosis is often difficult. Brucella organisms can be isolated from blood cultures, but the organism grows poorly and incubation may be needed for several weeks. Routine Brucella agglutination tests are negative in cases of infection with B. canis, since B. abortus antigen is used.

Treatment of brucellosis with most antibiotics results in high relapse rates. The best results are obtained from combination therapy with streptomycin and tetracycline or streptomycin and ampicillin.

LYMPHOCYTIC CHORIOMENINGITIS

Lymphocytic choriomeningitis virus is found in many rodent species and spreads to humans through contact with infected aerosols, direct animal contact or rodent bites. Colonies of pet hamsters have been responsible for many human infections.(32) Five to ten days after infection with the organism, fatigue and chills develop, followed by severe headache. A small number of patients progress to aseptic meningitis, which is characterized by a very high lymphocyte count in cerebrospinal fluid. Diagnosis is made by viral isolation or by rising antibody titers. Since the disease is self-limited, treatment is for symptomatic relief only. Occasionally, meningitis may become protracted.

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