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.

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.

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

COMPARISON OF A RAPID ENZYME-LINKED IMMUNOSORBANT ASSAY TEST WITH AN INDIRECT IMMUNOFLUORESCENT ANTIBODY TEST IN DIAGNOSING EHRLICHIA AND ANAPLASMA INFECTIONS IN DOGS

PURPOSE: The objective of this study is to compare the diagnostic value of commercial enzyme-linked immunosorbent assay (ELISA) with indirect immunofluorescent antibody test (IFA) in detecting immunoglobulin-G (IgG) antibodies to Ehrlichia canis and Anaplasma phagocytophilum. METHODS: Seventy-four serum samples, obtained from dogs believed to be naturally infected with E. canis or A. phagocytophilum, were analyzed. RESULTS: By ELISA, 48 (64.9%) samples were found positive for IgG to E. canis, 10 (13.5%) to A. phagocytophilum, 12 (16.2%) to both E. canis and A. phagocytophilum, and in 4 (5.4%) samples no presence of antibodies was detected. The number of serologically positive dogs for IgG was 44 (59.5%) to E. canis, 10 (13.5%) to A. phagocytophilum, 16 (21.6%) to both E. canis and A. phagocytophilum, and 4 (5.4%) were determined negative by means of IFA. In most samples the antibody titer did not exceed 1:80 but in 5 it reached a level of 1:320, and in other 4 of even above 1:640. CONCLUSIONS: This study shows that IFA assay is more sensitive than commercial ELISA rapid test when serum antibody titers are low.