Histopathologic findings of tularemia lymphadenitis.

Patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be diagnosed by PCR during acute infection or later in their clinical course by detection of virus-specific antibodies. While in theory complementary, both PCR and serologic tests have practical shortcomings. A retrospective study was performed in order to further define these limitations in a clinical context and to determine how to best utilize these tests in a coherent fashion. A total of 3,075 patients underwent both PCR and serology tests at University of California, Los Angeles (UCLA), in the study period. Among these, 2,731 (89%) had no positive tests at all, 73 (2%) had a positive PCR test and only negative serology tests, 144 (5%) had a positive serology test and only negative PCR tests, and 127 (4%) had positive PCR and serology tests. Approximately half of the patients with discordant results (i.e., PCR positive and serology negative or vice versa) had mistimed tests in reference to the course of their disease. PCR-positive patients who were asymptomatic or pregnant were less likely to generate a detectable humoral immune response to SARS-CoV-2. On a quantitative level, the log number of days between symptom onset and PCR test was positively correlated with cycle threshold (CT) values. However, there was no apparent relationship between PCR CT and serologic (arbitrary units per milliliter) results.

Vesiculobullous Lyme disease: A case series

The use of serologic testing to diagnose Lyme disease (LD) is a source of controversy. Expert recommendations also discourage the routine use of antibiotic therapy for prophylaxis of LD following tick bites, but the extent to which physicians in endemic areas have adopted these recommendations is not known. To assess the pattern of use of serologic testing and antibiotic therapy for tick bites and LD and associated charges for management in an endemic area. Active surveillance of patient-physician encounters for tick bites and LD. Primary care practices on the Eastern Shore of Maryland. Consecutive sample of 232 patients with tick bites, LD (defined by physician diagnosis in medical record), and suspected LD (physician notation of possible, but not definite LD) seen in 1995. Serologic testing for LD, test results, antibiotic therapy, and direct costs of management. Surveillance identified 142 patients (61.2%) with diagnoses of tick bites, 40 patients (17.2%) with LD, and 50 patients (21.6%) with suspected LD. Of the 142 patients seen for tick bites, 95 (67%) underwent serologic testing for LD. Of these, 93 patients had initial negative or equivocal results; 24 (26%) of the 93 had convalescent testing, with 1 seroconversion. Seventy-eight patients (55%) with a diagnosis of tick bite received antibiotic therapy. No patients with tick bite developed clinical LD. Serologic testing for LD was performed for 36 patients (90%) with a diagnosis of LD and 46 patients (92%) with suspected LD. In most cases, antibiotics were prescribed before serologic test results became available. Convalescent testing was not performed for 37 (86%) of the 43 patients with suspected LD who had initial negative or equivocal results. Of these 37 patients, 25 (68%) did not receive antibiotic therapy. Direct charges for treatment of these 232 patients totaled $47 595, one third of which was attributable to serologic testing. A total of 32% of direct charges were for patients with tick bites, 48% were for patients with LD, and 20% were for patients with suspected LD. In this setting, most patients consulting physicians for tick bites received prophylactic antibiotic therapy of unproven efficacy and underwent unnecessary, costly serologic testing. Despite almost universal use in this study, serologic testing for LD did not appear to influence treatment of patients diagnosed as having LD.

Toxoplasma gondii is a compulsory intracellular protozoan parasite with a wide range of host in warm-blooded vertebrates and has importance in terms of health and economy. Toxoplasmosis is very common because it can infect people with a variety of ways; ingestion of contaminated water and nutrients; raw or undercooked meats containing tissue cysts, blood transfusions, organ transplantantation and transplacental transfer. The aim of this study was to evaluate serologic and molecular test results of toxoplasmosis pre-diagnosed patients. Anti-T.gondii-IgG, anti-T.gondii-IgM ELISA, anti-T.gondii-IgM IFAT and anti-T.gondii-IgG avidity serological tests and PCR tests were applied by using blood, cerebrospinal fluid, amniotic fluid, pericardial fluid and abscess samples from patients who have admitted to Erciyes University Faculty of Medicine Department of Parasitology routine serology and molecular diagnosis laboratories with a pre-diagnosis of toxoplasmosis. Among 6547 patients 3.3% (n= 220) were only IgM positive, 9.2% were both IgG and IgM positive (n= 598). Among male patients, the positivity rates were lower and only IgM seropositive patients were 0.6% (n= 45) while the frequency of both IgG and IgM positive patients was 0.8% (n= 47). The number of both IgG and IgM seropositive cases among new borns, constituting 6.4% (n= 425) of the total number of patients, was 20 (0.3%) and the number of IgM seropositive samples was 25 (0.4%). Only 290 patients positive for IgM antibodies were studied for IFAT and 22 of these patients were positive for anti-T.gondii-IFAT IgM. Anti-T.gondii IgG avidity test was performed in all IgG positive patients regardless of their IgM seropositivity; low avidity was found in 0.7% (n= 18) of IgM-negative patients' sera and equivocal avidity was detected in 6.5% (n= 179). Low avidity was detected in 2.6% of IgM positive patients. Nine of the patients evaluated as anti-T.gondii IgM negative and IgG positive were detected as positive by PCR and two of them were negative. One of these PCR-positive patient's amniotic fluid was sent after the serological test results and detected as positive. Twenty CSF samples were studied by PCR and 7 samples were positive. Also, 8 blood samples which were anti-T.gondii IgM negative and IgG positive were found to bepositive in 7 and negative in one sample with PCR results, subsequently. PCR tests with pericardial fluid and abscess materials were found to be negative. In the case of suspicious or risky situations such as false negatives or false positives resulting from cross-reaction that can occur in ELISA tests, unnecessary medication or interventional approaches can be avoided by applying molecular-based testing at laboratories with appropriate infrastructure. For this reason, we believe that the application of molecular tests in addition to serological tests in risky situations may give more reliable results.

Toxoplasma gondii is a compulsory intracellular protozoan parasite with a wide range of host in warm-blooded vertebrates and has importance in terms of health and economy. Toxoplasmosis is very common because it can infect people with a variety of ways; ingestion of contaminated water and nutrients; raw or undercooked meats containing tissue cysts, blood transfusions, organ transplantantation and transplacental transfer. The aim of this study was to evaluate serologic and molecular test results of toxoplasmosis pre-diagnosed patients. Anti-T.gondii-IgG, anti-T.gondii-IgM ELISA, anti-T.gondii-IgM IFAT and anti-T.gondii-IgG avidity serological tests and PCR tests were applied by using blood, cerebrospinal fluid, amniotic fluid, pericardial fluid and abscess samples from patients who have admitted to Erciyes University Faculty of Medicine Department of Parasitology routine serology and molecular diagnosis laboratories with a pre-diagnosis of toxoplasmosis. Among 6547 patients 3.3% (n= 220) were only IgM positive, 9.2% were both IgG and IgM positive (n= 598). Among male patients, the positivity rates were lower and only IgM seropositive patients were 0.6% (n= 45) while the frequency of both IgG and IgM positive patients was 0.8% (n= 47). The number of both IgG and IgM seropositive cases among new borns, constituting 6.4% (n= 425) of the total number of patients, was 20 (0.3%) and the number of IgM seropositive samples was 25 (0.4%). Only 290 patients positive for IgM antibodies were studied for IFAT and 22 of these patients were positive for anti-T.gondii-IFAT IgM. Anti-T.gondii IgG avidity test was performed in all IgG positive patients regardless of their IgM seropositivity; low avidity was found in 0.7% (n= 18) of IgM-negative patients' sera and equivocal avidity was detected in 6.5% (n= 179). Low avidity was detected in 2.6% of IgM positive patients. Nine of the patients evaluated as anti-T.gondii IgM negative and IgG positive were detected as positive by PCR and two of them were negative. One of these PCR-positive patient's amniotic fluid was sent after the serological test results and detected as positive. Twenty CSF samples were studied by PCR and 7 samples were positive. Also, 8 blood samples which were anti-T.gondii IgM negative and IgG positive were found to bepositive in 7 and negative in one sample with PCR results, subsequently. PCR tests with pericardial fluid and abscess materials were found to be negative. In the case of suspicious or risky situations such as false negatives or false positives resulting from cross-reaction that can occur in ELISA tests, unnecessary medication or interventional approaches can be avoided by applying molecular-based testing at laboratories with appropriate infrastructure. For this reason, we believe that the application of molecular tests in addition to serological tests in risky situations may give more reliable results.

Toxoplasma gondii is an obligate intracellular coccidian pathogen, with domestic cats and other members of the Felidae family serving as its definitive hosts. The aim of the study was to identify risk factors for positive test results. A laboratory database was screened for T gondii PCR results from faecal samples and serology results (IgM, IgG) from serum/plasma taken from cats in Europe between January 2008 and December 2022. Logistic regression analysis was performed to identify risk factors associated with positive T gondii results, such as breed, age, sex, neuter status, regionality, seasonality, feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) status. Odds ratios (ORs) were calculated. A total of 45,523 cats were included: 14,500 (31.9%) tested positive by direct and/or indirect detection methods for T gondii (PCR: 126/7896 [1.6%], IgG: 14,148/37,882 [37.3%], IgM: 1539/37,882 [4.1%]). Age >5 years (IgG: OR 2.591, P <0.001; IgM: OR 1.954, P <0.001), European domestic shorthair cats/cross breeds (IgG: OR 3.848, P <0.001; IgM: OR 2.152, P <0.001), male sex (IgG: OR 1.134, P <0.001), neuter status in male (IgG: OR 0.536, P <0.001) and female cats (IgG: OR 0.577, P <0.001), FeLV antigen positivity (IgG: OR 1.358, P = 0.030) and FIV antibody positivity (IgG: OR 2.350, P <0.001; IgM: OR 2.650, P <0.001) significantly impacted the serological results. In PCR testing, neuter status had a significant impact in male (OR 2.455, P = 0.002) and female cats (OR 2.988, P <0.001). Serological and PCR results were significantly influenced by regionality for IgG (central: OR 1.454, P <0.001; north: OR 0.768, P <0.001; south: OR 0.526, P <0.001; east: OR 0.768, P <0.001; west: OR 0.709, P <0.001), IgM (central: OR 0.616, P <0.001; north: OR 1.456, P <0.001; south: OR 1.767, P <0.001; east: OR 1.456, P <0.001) and PCR testing (central: OR 0.460, P <0.001; north: OR 3.020, P = 0.002; east: OR 3.020, P = 0.002). Seasonality had a statistically significant impact on IgM (summer: OR 1.402, P <0.001; winter: OR 0.732, P <0.001) and PCR testing (autumn: OR 1.473, P = 0.038). Breed, age, sex, neuter status, seasonality and regionality significantly impacted serological results. Neuter status, seasonality and regionality significantly impacted the PCR results. Immunosuppression (FeLV/FIV) had a significant impact on serological results. PCR-positive cats shed oocysts and spread infection to other susceptible hosts, including humans. Surveillance is therefore recommended, taking into consideration the associated risk factors.

<i>Ehrlichia chaffeensis</i>in Child, Venezuela

Epidemiology of Tick Bites and Borreliosis in Children Attending Kindergarten or So-Called “Forest Kindergarten” in Southwest Germany

Diagnosis of red meat allergy with antigen-specific IgE tests in serum

To the Editor: African tick-bite fever (ATBF) is caused by Rickettsia africae and remains the most common tickborne rickettsiosis in sub-Saharan Africa (1,2). We describe an outbreak of ATBF in 10 of 34 French tourists on their return from South Africa in March 2005. Fever, skin rash, and multiple eschars on the legs developed in the index case-patient (patient 9, Table). After informed consent was obtained, the tourists completed a questionnaire for epidemiologic and clinical data. Acute- and convalescent-phase serum samples were collected when possible for serologic analysis performed at the Unite des Rickettsies. The samples were tested against a panel of antigens including R. typhi, Francisella tularensis, Coxiella burnetii, Borrelia burgdorferi, Anaplasma phagocytophylum, R. felis, R. helvetica, R. conorii subsp. conorii strain Malish, R. africae, R. sibirica mongolotimonae, R. massiliae, and R. slovaca, as previously described (3). A case of symptomatic confirmed ATBF was defined as clinical illness and positive serologic results against R. africae, whereas a case of probable ATBF was defined as typical clinical symptoms without definite serologic evidence of R. africae infection. Table Epidemiologic, clinical, and serologic information for 10 patients with African tick-bite fever* Of the 34 travelers, 30 completed the questionnaire and 20 consented to give at least 1 serum sample. After their return to France, symptoms compatible clinically with ATBF developed in 10 of the travelers (Table) and 9 had positive serologic results and/or a seroconversion for spotted fever group-rickettsia, including R. africae (Table). The median time from illness onset to serum testing was 19 days. Thus, 9 of the travelers had probable and 1 had possible (no serum was available) ATBF. Including both probable and possible cases, the illness rate for the whole group was 33.3% (10/30). None of the travelers reported a history of tick bite. The delay between probable exposure and onset of symptoms was 3-10 days (mean ± standard deviation 6.1 ± 1.9 days). Multiple eschars on the legs or arms were seen in 7 (70%) of 10 patients. Eight patients received doxycycline (200 mg per day) for a mean of 10.8 ± 5.9 days (range 5-20), 1 patient received pristinamycin for 8 days, and 1 patient received no treatment. All patients recovered fully without sequela; however, 6 patients reported convalescent-phase asthenia and 1 reported chronic insomnia, which had not occurred previously, for 2 months after the illness. Among the 10 remaining travelers, for whom a serum sample was available, with no clinical evidence of ATBF, 5 were positive for R. africae with only immunoglobulin M (IgM) at a titer of 1:32 in 4 cases and IgG at 1:128 with IgM at 1:32 in 1 case (an acute-phase serum from this patient showed IgG at 1:32 and IgM at 1:32). The 5 other travelers had negative serologic results. Results of serologic testing for other bacteria were negative for all travelers. Twenty-four travelers (80%), including the 10 symptomatic patients, reported using topical insect repellent daily. Most cases of ATBF are reported in clusters of travelers exposed to ticks during game hunting or safaris, as described here (1,3-5). The estimated incidence of African tick-bite fever in safari travelers is 4%-5.3% (4) but higher incidence may be reported as emphasized in our study. In our study, epidemiologic and clinical data for the 10 symptomatic patients were obtained in accordance with current knowledge of ATBF (2). Skin biopsy samples remain the best tool to isolate or detect R. africae (2,6). However, specific serologic tests, especially immunofluorescence assays, remain the most widely used microbiologic test worldwide (7). No commercially available test for ATBF exists but due to extensive cross-reactions between spotted fever group rickettsiosis, commercial kits based on the detection of R. conorii antibodies can be used for the diagnosis of ATBF. Most tourists reported using topical insect repellents without any efficacy. Applying repellents to exposed skin provides little protection against ticks because they can crawl underneath clothing and bite untreated portions of the body (8). Thus, treating clothing with synthetic pyrethroid insecticide is recommended to complement the topical repellant (8). In conclusion, our study emphasizes the importance of ATBF as a common cause of flulike illness in travelers returning from South Africa, but with a higher rate than malaria, typhoid fever, or other tropical fevers. The most important clinical clues are the presence of clustered cases with multiple inoculation eschars. Healthcare professionals who are providing advice should inform persons traveling to endemic areas of Africa of the risk of contracting ATBF and the importance of protecting themselves against tick bites. Chemoprophylaxis with doxycycline is not recommended, however, this recommendation may be evaluated in future clinical trials.

Alpha-gal syndrome (AGS) is a rare, tick-borne condition that is characterized by a delayed hypersensitivity reaction to galactose-α-1,3-galactose (alpha-gal), a carbohydrate found in mammalian meat products. AGS is increasingly recognized in adults; however, cases often remain underreported or misdiagnosed in children. We report on a 10-year-old male in Northeast Florida presenting with gastrointestinal symptoms, urticaria, and oropharyngeal itching. These symptoms developed hours after consuming a cheeseburger. His medical history revealed multiple previous Lone Star tick bites. After an alpha-gal IgE panel was performed, the elevated specific IgE levels, in addition to the patient’s prior history of tick bites, led to a diagnosis of AGS. The patient was prescribed avoidance of mammalian meat and an epinephrine auto-injector. There is a growing need for correct symptom recognition in pediatric cases, and improved clinical recognition may facilitate earlier diagnosis in pediatric patients.Florida’s warm climate and abundant wooded and marshy areas support tick activity. Unlike typical IgE-presenting allergens, AGS reactions may occur hours after ingestion, leading to cases remaining underreported or misdiagnosed. Repeated exposures can lead to more severe symptoms, emphasizing the need for early diagnosis. With very limited surveillance, the true prevalence and incidence of AGS in Florida are unknown due to underreporting, and this case report sheds light on the clinical presentation of a pediatric AGS case in Northeast Florida.

Purpose: The north-eastern Poland is an endemic region of tick-borne diseases. The aim of the study is to assess the prevalence of anti-Rickettsia antibodies in the inhabitants of the north-eastern Poland and to assess the risk of acute infection (rickettsiosis) after a tick bite. Other aim was to assess the risk of co-infection with other pathogens after a tick bite.Methods: Two types of examinations were performed: serological and molecular. Serological analysis was performed in 82 foresters and 82 farmers with a history of tick bite. The molecular study was performed in 540 patients with various symptoms after a tick bite. The control group consisted of 20 honorary blood donors with no tick bites in anamnesis. Anti-Rickettsia spp. antibodies titres were determined by ELISA: Rickettsia SFG IgG ELISA (DRG International Inc. USA). PCR tests were performed towards Rickettsia spp. Borrelia burgdorferi, Anaplasma phagocytophilum.Results: In 64 (39.02%) farmers and foresters, anti-Rickettsia IgG antibodies were detected. The presence of anti-Rickettsia IgG antibodies was confirmed in 42 foresters (51.22%) and in 22 farmers (26.83%). In control group, results of all tests were negative. Rickettsia spp. DNA has not been confirmed in any out of 540 (0%) symptomatic patients.Conclusions: Seroprevalence of Rickettsia spp. infection in north-eastern Poland is high, especially in people often bitten by ticks, which makes this pathogen potentially dangerous for humans. Prevalence of anti-Rickettsia IgG antibodies in foresters is higher than in farmers. Symptomatic infection with Rickettsia spp. in humans in north-eastern Poland is uncommon.

Chilblain-like lesions and COVID-19 infection: A prospective observational study at Spain's ground zero

The histopathologic findings of localized reactions to tick bites may present as diagnostic dilemmas, especially if there is no history of a tick bite, or if the tick's mouthparts are not present in the biopsied skin. Skin biopsies of patients with a clinical history of a tick bite were selected and reviewed with the aim of detecting a common histopathologic denominator which could serve as a useful clue to the diagnosis, especially when the tick's mouthparts are absent. Hematoxylin and eosin-stained slides of 15 skin biopsies of tick bites were retrieved from three dermatopathology and pathology laboratories. Where additional paraffin-embedded tissue was available, additional sections were also stained with periodic acid-Schiff (PAS) and phosphotungstic acid-hematoxylin (PTAH). In every case in which adequate tissue was available (13/ 15 biopsies), the capillaries and postcapillary venules of the superficial and deep vascular plexi adjacent to the attachment's site were filled with thrombi. Fibrin thrombi were seen in association with other more numerous thrombi characterized by homogeneous eosinophilic hyaline material similar to the cryoprecipitate present in type I (monoclonal) cryoglobulinemia. All thrombi were positive for PAS and PTAH; however, the latter staining was minimally present in the hyaline thrombi. In most cases, the site of the tick bite showed ulceration, with an underlying wedge-shaped superficial and deep perivascular and occasionally interstitial mixed lymphohistiocytic infiltrate. In addition, there were eosinophils, numerous neutrophils and extravasated erythrocytes. Other findings included suppurative necrosis (7/15) cases, giant-cell reaction (one case), fat necrosis (one case) and eccrine gland necrosis (one case). Vascular eosinophilic hyaline thrombi were found to be a frequent histologic manifestation of a tick bite. This finding may be related to the secretory products of the tick's saliva during inoculation. We believe that a tick bite should be suspected when focal intravascular hyaline occlusion is observed, and that it should be included in the differential diagnosis of type I (monoclonal) cryoglobulinemia, even if there is no history of a tick bite or if tick parts are not present in the skin biopsy specimen.

Prevalence and predictors of SARS-CoV-2 antibodies among solid organ transplant recipients with confirmed infection.