Emelia Osman

Diagnosis of extraintestinal microsporidiosis is always hampered due to non-specific symptoms and difficulty in diagnosis. This study aimed to compare the diagnostic utility of blood and faecal-based polymerase chain reaction (PCR) to detect microsporidiosis in immunocompromised patients. A total of 42 immunocompromised patients consisting of HIV-infected and chemotherapy-treated patients were enrolled. Paired faecal and blood samples were collected and subjected to PCR to detect Enterocytozoon bieneusi and Encephalitozoon spp. Faecal samples were microscopically screened for microsporidia spores. Overall, 42.9% (18/42) of patients were positive for microsporidiosis. Of this, 19.0% (8/42) and 4.8% (2/42) were positive by blood and stool PCR respectively. Meanwhile, 33.3% (14/42) of the faecal specimens were microscopically positive. Among the positive patients, 22.2% (4/18) had microsporidia confirmed by blood PCR and stool microscopy, suggestive of dissemination. Interestingly, the stool specimen in which microsporidia spores were detected via microscopy is not positive via PCR method. This highlights the limitation of the faecal-based detection method and the important use of blood samples for diagnosing extraintestinal microsporidiosis. Only E. bieneusi species were detected in all PCR-positive samples. This study highlights the diagnostic value of blood PCR in diagnosing extraintestinal microsporidiosis infections.

: Malaysia has maintained zero cases of indigenous human malaria since 2018. However, zoonotic malaria is still prevalent in underdeveloped areas and hard-to-reach populations. This study aimed to determine the prevalence of malaria among remote indigenous communities in Peninsular Malaysia. A cross-sectional survey was conducted in six settlements in Kelantan state, from June to October 2019. Blood samples were tested for malaria using microscopy and nested polymerase chain reaction (nPCR) targeting the Plasmodium cytochrome c oxidase subunit III (cox3) gene. Of the 1,954 individuals who appeared healthy, no malaria parasites were found using microscopy. However, nPCR revealed seven cases of Plasmodium knowlesi mono-infection (0.4%), and six out of seven infections were in the group of 19 to 40 years old (P = 0.026). No human malaria species were detected by nPCR. Analysis of the DNA sequences also showed high similarity that reflects common ancestry to other P. knowlesi isolates. These findings indicate low submicroscopic P. knowlesi infections among indigenous communities in Malaysia, requiring PCR-based surveillance to support malaria control activities in the country.

: Approximately 600 million people worldwide are infected with Strongyloides stercoralis. Many diagnostic laboratories use serology to detect the infection. SsRapid^® is a prototype IgG4 lateral flow test based on NIE recombinant protein. We compared SsRapid with two commercial IgG-ELISAs (Bordier and Euroimmun) using five sera groups (G1–5, N = 170). Healthy individuals from nonendemic areas (G1, N = 33) and Strongyloides larvae-positive patients (G2, N = 20) showed no significant difference (P > 0.05) among the three assays. The group of other parasitic infections (G3) showed that SsRapid results were more concordant with Bordier ELISA (73%, 35/48) than Euroimmun ELISA (65%, 31/48). In corticosteroid-treated cancer patients who were polymerase chain reaction–positive for Strongyloides (G4, N = 25), SsRapid showed a higher detection rate (28%, 7/25) than both ELISAs (4%, 1/25). Meanwhile, SsRapid showed significantly less infection prevalence among the endemic area population (G5) than the ELISAs. Overall, SsRapid showed good performance in detecting Strongyloides infection compared with the commercial IgG-ELISAs.

: Strongyloides infection may develop into fatal hyperinfection and dissemination syndrome in immunocompromised hosts. Despite suboptimal specificity issues, the detection of IgG antibodies by ELISA has been central in the serodiagnosis of Strongyloides infection. Recently, an IgG4-based lateral-flow test (SsRapid) using recombinant NIE (rNIE) protein with good diagnostic performance has been reported. This study assessed the result concordance between a commercial IgG-ELISA and the SsRapid. Additionally, we determined the Strongyloides seroprevalence and its association with clinical manifestations. Immunocompromised patients (N = 200) were from Hospital Canselor Tuanku Muhriz, Kuala Lumpur, Malaysia, and were diagnosed with HIV/AIDS, hematological malignancy, and solid organ cancers. Their plasma samples were tested using a commercial IgG-ELISA and SsRapid. A fair concordance (κ = 0.27–0.33; P < 0.05) between the tests was demonstrated. The SsRapid exhibited a significantly higher (P < 0.05) seroprevalence (10.5% [21/200]) compared with IgG-ELISA (7.5% [15/200]). After adsorption with rNIE, all SsRapid-positive samples tested negative with the rapid test, thus showing binding specificity. There was no significant association with clinical manifestations. This study revealed that SsRapid is a useful diagnostic tool for Strongyloides infection, and there is a notable seroprevalence among the immunocompromised patients.

Toxoplasma gondii is an opportunistic protozoan parasite known to affect the human brain. The infection has been associated with an increased incidence of schizophrenia; however, the link between the two conditions remains unclear. This study aimed to compare the plasma metabolome of schizophrenia and non-schizophrenia subjects with or without Toxoplasma infection. Untargeted metabolomic profiling was carried out by liquid chromatography-mass spectrometry. Elevation of the α-hydroxyglutaric acid level and reduced adenosine monophosphate, inosine, hypoxanthine and xanthine were found in the subjects with either toxoplasmosis or schizophrenia alone. These results suggest that purine catabolism is a common metabolic alteration in Toxoplasma infection and schizophrenia. The roles of these metabolites on the pathogenesis of schizophrenia in relation to Toxoplasma infection warrant further studies.

: A lateral flow rapid test for strongyloidiasis will greatly facilitate the control and elimination of the disease. Previously SsRapid prototype rapid test showed high diagnostic specificity to detect Strongyloides infection, determined using non-Strongyloides sera negative by IgG-ELISAs. Since high specificity is crucial before a test is used for public health control activities, further validation of its specificity is needed. Also, it needs to be ascertained whether non-Strongyloides sera positive by IgG-ELISAs and SsRapid are truly positive for Strongyloides or are cases of cross-reactivity. We performed 84 rapid tests (two types of dipsticks and cassettes) using 34 serum samples. They were divided into four groups based on Strongyloides infection and coinfection with other parasites and the availability of recombinant proteins and rapid tests for the latter. Sera was adsorbed using polystyrene microspheres beads separately coated with four recombinant parasite proteins. The small sample size is a limitation of this study; however, the overall results showed that the sera adsorption procedure was successful, and the SsRapid test is specific.

Schizophrenia is a serious mental disorder characterized by chronic relapsing episodes of psychosis. The disease is multifactorial, where infections, genetic vulnerability and environmental factors are involved in the development of the illness. Toxoplasma gondii is one of the parasites that has long been known associated with schizophrenia in many studies. To date, there is growing evidence of association between T. gondii infections and schizophrenia. Herein we report a rare case of reactivated toxoplasmosis in a schizophrenia individual. This patient was incidentally diagnosed with reactivated T. gondii infection. He denied any symptoms of toxoplasmosis but experienced a mild psychiatric auditory hallucination. Serology test for T. gondii immunoglobulin antibodies measured a high positive IgG titer (135.9 IU/ml) and negative for IgM. Interestingly, nested PCR exhibited a positive result for the type I strain of T. gondii dense granular (GRA) 7 gene (GRA7). This case highlights the detection of probable reactivation of toxoplasmosis in an immunocompetent schizophrenic patient without psychiatric treatment-resistant and remains asymptomatic for toxoplasmosis. Both serology and molecular tools have been a helpful aid in establishing the diagnosis. Nonetheless, early detection as in this case may aid the patient management in the future.