Acute Appendicitis Associated with Hantaan Virus Infection

Hantaviruses are Bunyaviridae viruses that cause hemorrhagic fever with renal syndrome (HFRS). Appendicitis caused by Hantaan virus has not been reported previously. An 81-year-old man who underwent laparoscopic appendectomy for suspected appendicitis based on abdominal pain, fever, hypotension, and computed tomography findings. Based on a suspicion of hemorrhagic fever with renal syndrome, the patient’s plasma was simultaneously analyzed using an indirect immunofluorescent antibody assay and nested reverse transcription–polymerase chain reaction (RT-PCR). The appendix tissue was also analyzed using nested RT-PCR and immunohistochemical (IHC) staining to identify the presence of Hantaan virus. Nested RT-PCR detected the presence of Hantaan virus, and indirect immunofluorescent antibody assay results revealed the presence of elevated antibody levels. Furthermore, IHC staining of the appendix tissue confirmed Hantaan virus antigens in the peripheral nerve bundle. Based on these findings, we confirmed the nerve tropism of the Hantaan virus. Hantaan virus in plasma and appendix tissue samples was confirmed using PCR and phylogenetic tree analysis. Moreover, we detected hypertrophy of the submucosa and periappendiceal adipose tissue nerve bundle along with Hantaan virus antigens in peripheral nerve bundles using IHC staining. Hence, we report that Hantaan virus infection may be accompanied by appendicitis.

Q Fever Endocarditis in Northeast Iran

This report presents a case of chronic Q fever endocarditis. A 60-year-old male farmer and rancher was admitted to the hospital with symptoms of weight loss, fever, severe sweating, weakness, and anorexia. PCR was negative for C. burnetii in the blood sample, but phase I and II IgG antibodies against C. burnetii were positive (1 : 16384 and 1 : 2048, respectively) by the indirect immunofluorescent assay (IFA). According to the adjusted Duke criteria, Q fever endocarditis was confirmed, and the patient was successfully treated with doxycycline and hydroxychloroquine.

Occurrence of antibodies anti-Toxoplasma gondii among sheltered and free-roaming cats within a university campus

The present study aimed to assess anti-T. gondii antibodies in sheltered and free-roaming cats within a university campus that has an overlapping population of humans and livestock. A total of 51 cats were tested for anti-T. gondii antibodies using the indirect immunofluorescent antibody test. Overall, 8/51 cats (15.7%) were seropositive. Cats were more likely to be seropositive when free-roaming (p= 0.008) and with presence of skin lesions (p= 0.042), and less likely with < 1 year of age (p= 0.021), probably due to higher environmental exposure and infected prey consumption. The presence of seropositive free-roaming cats whose areas overlapped those occupied by humans and livestock may suggest an increased on-campus chance of T. gondii occurrence.

Dr. Naides reply

We thank Dr. Russell for raising the issue of reporting the false positivity rate of antinuclear antibody (ANA) indirect immunofluorescent assay (IFA) testing.1 It is difficult, however, for a laboratory to state a false positive rate, per se, as the determination of “falseness” is dependent on clinical evaluation that is typically not available to most laboratories.

Sensitivity of a novel immunofluorescent staining method for Circulating tumor cells identification and its clinical application in predicting cancer recurrence in breast cancer

Circulating tumor cells (CTC) enumeration has been clinically adopted as important prognostic factor in different cancers, but many of CTCs isolation or identification apporches did not have clinical data. In this study, we developed a novel indirect immunofluorescent staining method targeting EpCAM or cytokeratin for CTC identification. Peripheral blood samples from twenty healthy donors and thirty-six cancer patients were used for cutoff establishment and sensitivity test. An immunofluorescent intensity threshold value of 5080 for the EpCAM or cytokeratin staining led to highly accurate cell classification (95% sensitivity and >99% specificity), and with the cut-off point of 2 CTCs, the sensitivity of CTC detection was 54.2% (19/35) in the diagnosis of patients with different cancer. Besides, the presence of CTCs defined as having >2 CTCs/7.5 mL might be associated with cancer staging and occurred three weeks earlier than cancer relapse in a breast cancer patient, and thus was consider a clinically useful tool to monitor tumor recurrence during chemotherapy.

Seroconversion of Indirect Immunofluorescent Antibody IgM and IgG in Melioidosis

Background: There are several serological tests used in the diagnosis of melioidosis. However, the interpretation of the results can be problematic in endemic areas because there might be a high background positivity due to previous exposure. Objective: This study aimed to determine the usefulness of Indirect Immunofluorescent Antibody (IFA) IgM and IgG in the diagnosis of melioidosis and the time for seroconversion. Methodology: We prospectively studied the trend of IFA IgM and IgG in 40 patients with culture-confirmed melioidosis over three months at six different time points (days 1, 8, 15, 30, 60, and 90). Results: From the results, 37.5% and 32.5% of patients had IFA IgM and IgG of ≤ 1:20 respectively on day 1 when the blood culture was positive. The natural log (ln) of the titres was used for the analysis. Repeated measures ANOVA showed significant changes in both IgM (p= 0.001) and IgG (p= 0.045) respectively throughout six sampling time points. Both the means of ln IgM and ln IgG peaked at day 15. At day 90, mean ln IgG remained high but mean ln IgM dropped to a level below that of day one. All culture-confirmed melioidosis patients recorded a maximum IFA IgM titre of at least 1: 80, but all subsequently dropped to below this level at day 90. Conclusion: IFA IgM is a more useful diagnostic serological marker than IFA IgG in acute melioidosis. Bangladesh Journal of Infectious Diseases 2020;7(2):61-66

Vertical transmission and kinetic of antibodies anti-Neospora caninum in naturally infected lambs in the semiarid region of Brazil

Aimed with this study to evaluate vertical transmission of Neospora caninum in naturally infected sheep and to monitor the kinetics of antibodies against this protozoon in their lambs. Therefore, 48 pregnant ewes, from five herds, were divided into two groups: G1 - positive for anti-N. caninum antibodies, with 19 animals; and G2 - seronegative, with 29 animals. Blood samples were taken from the ewes and their lambs, immediately after birth, before ingesting colostrum, and 2, 7, 14, 21, 28, 35, 42, 49 and 56 days after birth. Analysis on serum antibodies was performed using the indirect immunofluorescent antibody test. Among the 19 seropositive mothers, six (31.6%) gave birth to lambs seropositive before ingesting colostrum and it was found that these lambs remained positive until the end of the study (56 days). Only one of the lambs, from a ewe that presented an antibody titer of 200, seroconverted after ingestion of colostrum. All the lambs that had been born from negative mothers remained negative throughout the experimental period. It was concluded that transplacental transmission was an important form of diffusion of N. caninum in the herds studied and that seropositive lambs maintained circulating antibodies during the period analyzed.

Serodiagnosis of Visceral Leishmaniasis in Northeastern Italy: Evaluation of Seven Serological Tests

This study compares the performance of seven assays, including two ELISA (Leishmania ELISA IgG + IgM, Vircell Microbiologists; Leishmania infantum IgG ELISA, NovaTec), three rK39-based immunochromatographic tests (rK39-ICTs) (Leishmania Dipstick Rapydtest, Apacor; On Site Leishmania IgG/IgM Combo Rapid Test, CTK Biotech; LEISHMANIA Strip quick Test, Cypress Diagnostic), one indirect immunofluorescent antibody test (IFAT) (Leishmania-Spot IF, BioMérieux), and one western blot (WB) (Leishmania WESTERN BLOT IgG, LDBio Diagnostics) for serodiagnosis of visceral leishmaniasis (VL). Serum samples from 27 VL patients living in northeastern Italy were analyzed, as well as the serum samples from 50 individuals in whom VL diagnosis was excluded. The WB and the IFAT had 96% sensitivity, followed by the ELISA (63% and 74%, respectively). The rK39-ICT exhibited the worst performance among the serological tests, with sensitivities ranging from 52% to 70%. By combining selected ELISA/ICT, the sensitivity of VL detection reached 89%. IFAT and WB outperformed ELISA and rK39-ICT by possessing optimal sensitivity, but their high cost and complexity of execution would not allow their employment as screening tests. In conclusion, the combination of easy-to-perform tests, such as ICT and ELISA, could improve sensitivity in the serodiagnosis of Mediterranean VL.