Positive Serologic Test Results Research Articles

Longitudinal study of the antibody response to recombinant Entamoeba histolytica antigens in patients with amebic liver abscess.

Serology is a critical component in the diagnosis of amebic liver abscess. However, in areas endemic for amebiasis there is a high background level of seropositivity for amebiasis (owing to previous infection with Entamoeba histolytica), which may complicate the interpretation of a positive serologic test result. Recently, we reported that serologic tests based on recombinant E. histolytica antigens might offer improved diagnosis of current invasive amebiasis because they apparently differentiated active infection from past exposure to the parasite. To confirm this finding, we have performed a longitudinal study on 20 patients with amebic liver abscess by examining their seroreactivity over time with recombinant versions of two major E. histolytica proteins, the serine rich E. histolytica protein (SREHP), and the 170-kD subunit of the galactose-specific adhesin. We found that more than 50% of the patients examined had become seronegative by one or both recombinant tests within 180 days of their diagnosis of amebic liver abscess. In the case of the recombinant SREHP-based tests, 12 patients had become seronegative 90 days after presentation. In contrast, all patients remained seropositive by a standard conventional test, an indirect hemagglutination test, at more than six months after presentation. Our study shows that patients lose seroreactivity with the recombinant SREHP or 170-kD antigen-based tests more rapidly than with a conventional serologic test; this may make them useful for the serologic diagnosis of amebiasis in endemic areas.

Detecting infections of chickens with recent Salmonella pullorum isolates using standard serological methods

Despite extensive testing for Salmonella pullorum infections in commercial poultry, occasional outbreaks of pullorum disease still occur. In some recent instances, questions have been raised about whether standard serological assays, which employ antigen strains selected several decades ago, are still able to detect currently prevalent S. pullorum strains. The present study evaluated the ability of standard rapid whole-blood plate agglutination test and serum tube agglutination test antigens to detect infection in Single Comb White Leghorn hens inoculated with large oral doses of six recent S. pullorum isolates. Two commercially available plate test antigens were obtained and three tube test antigens were prepared. All five antigens identified most inoculated hens as seropositive, although some differences in sensitivity were evident between the two assay types and between the two plate test antigens. The antigenic composition of the tube test antigens did not affect their ability to detect infections with the various inoculum strains. Regardless of the antigen used, hens infected with antigenically intermediate or variant S. pullorum strains were detected as seropositive less often than were hens infected with antigenically standard strains. Positive culturing results for S. pullorum in the livers and ovaries of infected hens were nearly always predicted by positive serological test results.

Correlation of seroreactivity with response to antibiotics in pediatric Lyme borreliosis.

Response to treatment with antibiotics was compared with serologic reactivity and clinical symptoms in a pediatric population with presumptive diagnoses of Lyme borreliosis. The population analyzed for this study consisted of a subset of a larger Lyme clinic population being monitored as part of a prospective study on pediatric Lyme borreliosis. All patients resided in an area in which Ixodes scapularis and Borrelia burgdorferi are considered endemic. Serum from patients was tested by enzyme-linked immunosorbent assay and Western blotting. Response to antibiotics was evaluated by members of a pediatric Lyme clinic. Results showed that positive serologic test results correlate with a favorable response to antibiotics, as does the presence of erythema migrans (EM), regardless of serologic status. Seronegative patients without EM had chronic fatigue and arthralgia and/or myalgia as primary symptoms and did not respond to antibiotics, even when multiple courses of treatment were given. These results indicate that serologic tests designed to have high specificity can reliably rule out Lyme borreliosis in patients with chronic symptoms, thus preventing unnecessary treatment with antibiotics.

Clinical and serologic evaluation of cats with cryptococcosis

Objective To evaluate the long-term clinical outcomes and serologic changes in cryptococcal antigen and antibody titers in cats with confirmed Cryptococcus neoformans infection. Design Prospective case series. Animals 47 cats with cryptococcosis. Procedure Cats included in this study were determined to have cryptococcosis on the basis of identification of C neoformans on histologic or cytologic examination, isolation of C neoformans in culture, or positive serologic test results for cryptococcal antigens. Information concerning the signalment, history, physical examination findings, FeLV and feline immunodeficiency virus status, serologic testing, treatment, and outcome for each cat was requested on a survey form. Follow-up measurements of serum cryptococcal antigen and antibody titers were requested for all surviving cats. Results Signalment and clinical signs of cats with cryptococcosis reported here were consistent with previous reports. Treatment consisted primarily of azole antifungal drugs. All cats were seronegative for cryptococcal antibodly titers, whether tested initially or at follow-up examination. All but 1 cat tested were seropositive for cryptococeal antigens when initially tested. Cats with and without clinical signs of C neoformans infection were seropositive for cryptococcal antigens months to years after initial diagnosis of cryptococcosis. Clinical Implications The results of this study indicate that serum titers to cryptococcal antigens in cats can persist with or without clinical signs for months to years after an initial diagnosis of cryptococcosis is made. Repeated evaluation of serum cryptococcal antigen titers is advised during the treatment of cats to monitor progress, evaluate prognosis, and guide cessation of treatment. (J Am Vet Med Assoc 1996;209:1110-1113)

Gastric syphilis: Polymerase chain reaction detection of treponemal DNA in pseudolymphomatous lesions

Syphilis is an unexpected diagnosis in the stomach. To establish the diagnosis, evidence of Treponema pallidum in the gastric lesion is necessary. However, it is sometimes difficult to prove the presence of the organisms by conventional methods. The authors describe two cases of early gastric syphilis with pseudolymphomatous histology in which T pallidum gene was detected by the polymerase chain reaction (PCR) using paraffin biopsy sections. The gastric lesion of each case endoscopically and histologically simulated that of malignant lymphoma. However, no clonality was proved by immunohistochemistry or PCR gene rearrangement analysis. No spirochetal organisms were detected with certainty by Warthin-Starry silver stain, whereas the organisms were shown by immunofluorescent stain in one patient. A PCR study showed the treponemal DNA in both patients, and its validity was supported by a direct sequencing and a restriction enzyme digestion. Positive results of serological tests for syphilis and regression of the lesions after antisyphilitic treatment were confirmatory of the diagnosis. Gastric syphilis should be considered as a differential diagnosis when an atypical lymphoid infiltrate fails to show monoclonality. The present PCR method would be helpful in showing T pallidum using routinely processed small biopsy specimens as the tissue source.

Lyme disease surveillance in Maryland, 1992

The incidence of Lyme disease (LD) reported to the Maryland Department of Health and Mental Hygiene during 1992 was 6.5 100,000 population, ranging from 29.3 cases/100,000 on the Eastern Shore (74.4% of all cases) to no cases in the mountains of western Maryland. Among the 317 reported patients, 44.4% gave a history of tick exposure and 78.9% had positive serologic test results. For the 187 (59.0%) patients meeting the Centers for Disease Control and Prevention (CDC) surveillance case definition, erythema migrans (EM) occurred in 69.5%, with arthritic (26.7%), neurologic (13.4%), and cardiac (2.1%) manifestations being less frequent. Patients not meeting the surveillance case definition were significantly more likely to have influenza-like symptoms, a smaller rash, and arthralgia. Patients meeting the CDC criteria were more likely to have an onset during the major transmission season in the summer (odds ratio (OR): 2.1; confidence interval (CI): 1.2 to 3.6) since this was the time when most ( 115 130 ) patients with EM were detected. Positive serologic results were more likely (OR: 2.2; CI: 1.2 to 4.2) in those not meeting the case definition. The treatment given to patients thought to have LD was almost always that recommended in the literature and there was no difference between treatment prescribed for patients meeting and those not meeting the case definition. These data show that physicians in Maryland are treating many patients for LD who are clinically diagnosed as having LD (e.g., febrile patients with flulike symptoms, patients with arthralgias or erythematous rashes < 5 cm in size) and who have positive serologic test results but who do not meet the CDC surveillance case definition. These patients and the large number of unreported patients being seen and treated for LD or tick bites must be added to the overall burden of LD in the state.

Diagnosis and treatment of hepatic hydatid cysts with the aid of echo-guided percutaneous cyst puncture.

The usefulness of echo-guided percutaneous cyst puncture in the diagnosis and treatment of hepatic hydatid cysts was assessed in a study of 45 patients referred to the Department of Tropical Medicine at Kasr El Aini Hospital in Cairo. All subjects had at least one hepatic cyst detected by ultrasonography (54 cysts in all), and 42 patients had positive results in serological tests for antibodies to Echinococcus granulosus. The majority of cysts were in the right hepatic lobe (40 cysts), were anechoic (51), and were rounded and smooth (49). All 45 active cysts (44 anechoic, rounded, and smooth; one anechoic and septated) yielded clear watery fluid containing scolices and exhibited elevated pressure on percutaneous puncture. In contrast, all nine inactive cysts yielded cloudy yellowish fluid without detectable scolices and did not display elevated pressure on puncture. The latter cysts were anechoic and elliptical (two cysts); anechoic and septated (one); anechoic with a calcified wall (one) or a detached germinal layer (two); or rounded with coarse echoes (three). Treatment by injection of a scolicidal agent (hypertonic saline) before withdrawal of the needle used for aspiration gave excellent results and was not associated with complications. Forty-three of the 45 patients had no clinical or ultrasonographic evidence of recurrent or new hepatic cysts after 3 years of follow-up.

Cutaneous Vasculitis and Rheumatoid Factor Positivity as Presenting Signs of Hepatitis C Virus—Induced Mixed Cryoglobulinemia

Hepatitis C virus (HCV) infection is associated with mixed cryoglobulinemia, which can cause a vasculitis affecting various organs. To determine the prevalence of cutaneous vasculitis in patients infected with HCV, information concerning a series of 408 HCV antibody-positive outpatients was analyzed. Patients with a skin eruption were evaluated by a dermatologist for objective evidence of cutaneous vasculitis, and the sensitivity of cryoglobulins was compared with that of rheumatoid factor activity as a serologic marker of mixed cryoglobulinemia in these patients. Cutaneous vasculitis was identified in 10 of 408 HCV-infected patients (prevalence of at least 2%). The vasculitis was manifested as palpable purpura in eight patients, livedo reticularis in one patient, and urticaria in one patient. The skin eruption was a major presenting feature in each of the 10 patients and even led to the discovery of occult HCV infection in two patients. Histologic examination revealed leukocytoclastic vasculitis in six patients and necrotizing arteritis consistent with polyarteritis nodosa in two patients. All 10 patients had chronic active hepatitis and exhibited rheumatoid factor activity. Variable features attributable to mixed cryoglobulinemia included arthropathy, central nervous system abnormalities, and glomerular disease. Serum cryoglobulins were detected in only four patients. Practitioners should be alert to the possibility of HCV infection in patients presenting with palpable purpura, livedo reticularis, or urticaria, in which the underlying histologic features are those of leukocytoclastic vasculitis or necrotizing panarteritis. Positive serologic test results for HCV antibody and rheumatoid factor in such patients virtually confirm the diagnosis of HCV-induced mixed cryoglobulinemia.

Short Report: An Outbreak of Trichinosis in Navarra, Spain

Trichinosis is an infection contracted by ingestion of meat containing viable larvae of the nematode Trichinella spiralis. This report concerns an outbreak of infections with this parasite in Navarra, Spain that was associated with home-prepared pork products. After the detection of a person with trichinosis, a study of all subjects that had ingested meat from the presumably infected pork was carried out. Forty-four members of eight families were enrolled in the study. Ten had symptoms suggestive of trichinosis, 20 had hypereosinophilia, and 15 had positive serologic test results for anti-Trichinella antibodies. Three groups could be distinguished according to the kind of product each subject had ingested (pork sausage, blood pudding, and loin). Twelve months later, all had a normal eosinophil count and a negative serology.

Pulmonary paragonimiasis: clinical and experimental studies.

Pulmonary paragonimiasis is a disease caused by a lung fluke. It is endemic to East Asia, but there have been several case reports in North America. Human infestation occurs by ingestion of raw or incompletely cooked freshwater crab or crayfish infected with metacercaria. A retrospective study was performed with 78 patients who lived in South Korea and had chest radiographic findings of pleuropulmonary disease; it was subsequently shown that they had paragonimiasis. The diagnosis was based on positive results of serologic tests for Paragonimus-specific antibody or on the detection of eggs in sputum samples. Radiologic findings from these 78 patients were correlated with the pathologic and radiologic findings from a study of experimentally induced pulmonary paragonimiasis in 21 cats. Findings from the correlative study document that the typical radiologic manifestations of pulmonary paragonimiasis vary with the stage of the disease. Early findings include pneumothorax or hydropneumothorax, focal airspace consolidation, and linear opacities and are caused by the migration of juvenile worms. Later findings include thin-walled cysts, dense masslike consolidation, nodules, or bronchiectasis and are due to worm cysts.

The Overdiagnosis of Lyme Disease

To analyze the diagnoses, serological test results, and treatment results of the patients evaluated in a Lyme disease clinic, both prior to referral and from current evaluation. Retrospective case survey of prescreened patients. Research and diagnostic Lyme disease clinic in a university hospital. All 788 patients referred to the clinic during a 4.5-year period who were thought by the referring physician or the patient to have a diagnosis of Lyme disease. Symptoms and signs of disease, immunodiagnostic tests of Lyme disease, and tests of neurological function. Of the 788 patients, 180 (23%) had active Lyme disease, usually arthritis, encephalopathy, or polyneuropathy. One hundred fifty-six patients (20%) had previous Lyme disease and another current illness, most commonly chronic fatigue syndrome or fibromyalgia; and in 49 patients, these symptoms began soon after objective manifestations of Lyme disease. The remaining 452 patients (57%) did not have Lyme disease. The majority of these patients also had the chronic fatigue syndrome or fibromyalgia; the others usually had rheumatic or neurological diseases. Of the patients who did not have Lyme disease, 45% had had positive serological test results for Lyme disease in other laboratories, but all were seronegative in our laboratory. Prior to referral, 409 of the 788 patients had been treated with antibiotic therapy. In 322 (79%) of these patients, the reason for lack of response was incorrect diagnosis. Only a minority of the patients referred to the clinic met diagnostic criteria for Lyme disease. The most common reason for lack of response to antibiotic therapy was misdiagnosis.

Blastomycosis in patients with the acquired immunodeficiency syndrome.

To describe the clinical, demographic, radiographic, diagnostic, and therapeutic aspects of blastomycosis in patients with the acquired immunodeficiency syndrome (AIDS). A retrospective survey. Ten university medical centers and community hospitals, six in geographic areas endemic for Blastomyces dermatitidis, and four outside the endemic area. We identified 15 patients with blastomycosis and positive serologic test results for human immunodeficiency virus (HIV). A diagnosis of blastomycosis was based on a positive culture (14 patients) or typical histopathologic features (one patient) for B. dermatitidis in clinical specimens. Twelve of 15 patients had a previous or concomitant AIDS-defining illness at the time of diagnosis of blastomycosis, and only one patient had a CD4 lymphocyte count of greater than 200 cells/mm3. Two patterns of disease emerged: localized pulmonary involvement (seven patients), and disseminated or extrapulmonary blastomycosis (eight patients). Central nervous system involvement was common (40%). Six patients died within 21 days of presentation with blastomycosis, including four patients with disseminated and two with fulminant pulmonary disease. Among the nine patients who survived longer than 1 month, all received amphotericin B as initial antifungal therapy, and most received subsequent therapy with ketoconazole. Only two of these nine patients died with evidence of progressive blastomycosis. Blastomycosis is a late and frequently fatal infectious complication in a few patients with AIDS. In these patients, overwhelming disseminated disease including involvement of the central nervous system is common, and it is associated with a high early mortality. Initial therapy with amphotericin B is appropriate in patients with AIDS and presumptive blastomycosis.

Immunological characterization of a low molecular mass polypeptidic antigen ofBorrelia burgdorferi

The presence of a low molecular mass polypeptidic antigen in Borrelia burgdorferi was described. The protein was exposed at the bacterial surface since it was clearly identified by mAb 3H4 using the immunofluorescence test performed with living bacteria. This antigen was cleaved by proteinase K treatment, whereas it was resistant to the action of chymotrypsin, trypsin and thermolysin. Western blotting analysis of the immunological reactivity of this antigenic structure performed using monoclonal antibody, mouse-immune ascitic fluids raised against B. burgdorferi and other spirochetes, sera from patients with Lyme disease and other infirmities in which false positive results in serological tests for B. burgdorferi have been described, demonstrated that this protein expresses only species-specific epitopes which may be recognized during human B. burgdorferi infections.

Branch Retinal Artery Occlusion Associated With Lyme Disease

Lyme borreliosis is a tick-borne spirochetal illness that may involve numerous organs. Multiple ocular manifestations of Lyme disease have been reported, including anterior uveitis, vitritis, episcleritis, conjunctivitis, keratitis, choroiditis, and exudative retinal detachment. 1 Several neuro-ophthalmologic complications have also been recognized. 1 We recently treated a patient with a branch retinal artery occlusion and positive results of serologic tests to detect Lyme disease who responded well to antibiotic therapy. To our knowledge, this is a new ocular manifestation of Lyme disease. Report of a Case. —A 37-year-old white woman awoke with a scotoma above fixation in her left eye. For the previous several months, she had generalized arthralgias and fatigue. Two months before presentation, she developed floaters in both eyes as well as daily, throbbing headaches. She was not pregnant and took no medications or birth control pills. There was no known history of a tick bite or skin rash.

Differential diagnosis of bacterial myositis in AIDS: evaluation with MR imaging.

Magnetic resonance (MR) imaging was used to assess for the presence of bacterial myositis, rare outside the tropics, in 13 patients with either the acquired immunodeficiency syndrome (AIDS) (n = 11) or positive results of serologic tests for the human immunodeficiency virus but without other evidence of AIDS (n = 2). Bacterial myositis was diagnosed in six patients: in five it was caused by pyogenic bacteria, and in the other, by Mycobacterium tuberculosis; in each patient, little or no subcutaneous tissue alteration occurred. On T1-weighted images in three patients, muscle abscesses showed a rim of increased signal intensity corresponding to margins between drainable pus and edematous muscle. Subcutaneous tissues appeared normal in patients with bacterial myositis but was not in the others, in whom muscle abnormalities tended to be less prominent. The latter group included patients with lymphoma (n = 1), Kaposi sarcoma (n = 2), and carbunculosis (n = 1), and three patients in whom no diagnosis was made; lymphedema was presumed to account for imaging abnormalities in four of the latter group.

Routine Screening for Syphilis Is Justified in Patients Admitted to Psychiatric, Alcohol, and Drug Rehabilitation Wards of the Veterans Administration Medical Center

Of 1515 patients admitted to psychiatric, alcohol, and drug rehabilitation services in the Veterans Administration Medical Center, Buffalo, NY, during the year 1987, who were screened by serologic tests for syphilis, 16 (1.05%) had positive rapid plasma reagin and fluorescent treponemal antibody-absorption tests for syphilis. A positive serologic test result was not suspected on clinical grounds in any of these patients. All were detected by routine screening. Of the 16 patients, 15 had charts available for review. Seven patients were treated for primary or late syphilis; four patients had received previous treatment; and four patients had no evaluation of test results and received no treatment. Routine screening of hospitalized patients who are alcohol or drug abusers is justified, but close follow-up is necessary to make screening meaningful.

Brucellosis contracted during foreign travel

Brucellosis, a bacterial infection, is rarely seen in the United States. It occurs mostly in people who work with domestic animals and animal products. However, this patient became infected while in Yugoslavia, and diagnosis was delayed by the gap between appearance of symptoms and positive results of serologic tests. Brucellosis should be suspected in a patient with unexplained fever, especially if he or she has traveled to a country where unpasteurized dairy products are common.

A review of refugee medical screening in New South Wales.

Public health concern in relation to refugees arriving in New South Wales is due to the high prevalence of tuberculosis, syphilis and hepatitis B infection in some refugee groups. Other infectious diseases (with the exception of malaria in the Northern Territory and Queensland) do not pose a significant threat to public health owing to their low prevalence (which may result from overseas screening and treatment) and/or low infectivity in Australian conditions. Because of overseas screening by the Commonwealth Government before the departure of the refugees, it was uncommon in 1984 for previously undetected tuberculosis to be detected when refugees were screened on arrival in Sydney (found in only one in 800 refugees who underwent screening). However, of the refugees in Sydney who had positive results of serological tests for syphilis, a substantial proportion (at times in excess of 50%) had had a negative result at the overseas screening; subsequent follow-up of those with positive serological results indicated inactive disease in almost all cases. There is a need to monitor the infectious disease prevalence and the effectiveness of overseas screening of refugees by on-arrival screening; decisions about screening procedures and the selection of particular incoming refugee groups for screening should be based on sound epidemiological and clinical analysis.

Syphilis and Leprosy

To the Editor.— I was pleased to see one of the recent issues ofThe Journalcontaining a good amount of material on sexually transmitted disease (STDs). Within one issue, there were two articles on atypical manifestations of gonococcal infections (1981; 246:242, 246), an article on secondary syphilis (1981;246:250), and an announcement on the First STD World Congress for November 1981 (1981; 246:217). One dermatology question in the same issue concerned a case of presumed alopecia areata in a 26-year-old man with oral ulcers, cervical lymphadenopathy, arthralgias, anemia, and, possibly, hepatitis (1981; 246:284). All of these signs and symptoms may occur with secondary syphilis, although the moth-eaten alopecia of syphilis may involve more diffuse thinning of the hair rather than the "exclamation point" hairs seen in bald spots in alopecia areata. 1 Syphilitic alopecia, of course, is accompanied by positive serological test results. Since syphilis is so easily treated in

Chlamydia trachomatisand respiratory disease in infants

Eleven infants under six months of age with respiratory symptoms and positive results of serological tests for Chlamydia trachomatis, including an infant from whom chlamydiae were isolate, are presented. The three distinct patterns of illness in these infants were a bronchitis with paroxysmal coughing, a bronchiolitis syndrome, and a diffuse afebrile pneumonia. We conclude that chlamydial respiratory disease should be considered in Australian infants with the described features. The diagnosis can be confirmed by immuno-fluorescence.