The switch from bradyzoites to tachyzoites is the fundamental pathogenic event that leads to Toxoplasma gondii encephalitis (TE) in patients with AIDS. Distinction between these stages is difficult, particularly when specific treatment has been started. A new approach consisting of a nested PCR (n-PCR) assay was performed on cerebrospinal fluid (CSF) specimens collected from AIDS patients with TE before or after antiparasitic therapy was initiated, to assess the efficacy of primer sets which amplify target sequences expressed on bradyzoites (SAG4 and MAG1), tachyzoites (SAG1) or both stages (B1) of T. gondii. CSF specimens were obtained from 46 patients with AIDS, of whom 27 had TE (16 first episode, 11 relapse) and 19 had other AIDS-related brain lesions (AIDS-OBL) in the absence of TE. CSF specimens from 26 HIV-negative and immunocompetent patients were also checked. All samples were tested with different primer pairs targeting the B1, SAG-1, SAG-4 and MAG-1 genes. With B1, 75% of patients with first episodes of TE were positive, compared with 36.3% of those with relapse of TE and 5.2% of those with AIDS-OLB. The SAG1 gene yielded positive values in 28.7% and 45.4% of patients with first episodes of TE or relapse of TE, respectively, and in none of the controls. With the SAG4 and MAG1 genes, 72.7% of patients with relapse of TE were detected, compared with 25% of patients with first episodes of TE and 5.2% with AIDS-OLB. None of the HIV-negative subjects showed positive PCR reactions. These results demonstrate that specific primers for the genes SAG4, MAG1 and SAG1 may be useful in AIDS patients with relapse of TE, in whom the use of PCR targeting the B1 gene may fail to detect DNA, especially when prophylaxis or treatment has been started.

Neurological diseases and a variety of neoplasms frequently occur in AIDS patients. Human JC and BK polyomaviruses have been associated with neurological disorders in such patients. SV40 polyomavirus sequences have been detected in human brain tumours, other neoplasms and normal tissues. JCV, BKV and SV40 DNA sequences were investigated in cerebrospinal¯uid (CSF) samples from 12 AIDS patients affected by different neurological disorders, by PCR assay and ®lter hybridisation with speci®c internal oligoprobes, and DNA sequencing. Three of the 12 CSF samples were positive for JCV (one sample) or SV40 (one) DNA, or both (one). No sample was positive for BKV DNA. JCV-and SV40-speci®c genomic regions were con®rmed by DNA sequencing. CSF samples from the two patients diagnosed clinically as having progressive multifocal leukoencephalopathy (PML) contained either JCV (one sample) or SV40 (one) DNA. The CSF found to contain both JCV and SV40 DNA originated from a patient with a cerebral mass lesion of unknown aetiology. These results suggest that SV40 may be involved in the aetiology of PML in AIDS patients, and raise the possibility that SV40 and JCV may act synergically in vivo to enhance their pathogenicity.

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Background and aimsOlfactory and gustatory dysfunctions were presented in a high percentage of COVID-19 cases. Most of them are represented by quantitative disorders. Qualitative alterations were established in a small proportion. During the Covid-19 pandemic, there is a need to make a differential diagnosis (DD) of olfactory and gustatory disorders. MethodsClinical case of a 64-year-old man presented with dairy food cacosmia and dysgeusia for the last two weeks, and night sweats. From medical history we found that our patient recovered from COVID-19 infection, one month ago. ResultsBased on some studies, patients with COVID-19 infection, presented moderate to severe olfactory or gustatory dysfunctions for long-term, in convalescent period. It's important to make a DD of smell and taste impairements and choose the necessary treatment. Esophageal candidiasis was diagnosed in our patient. After 21 days of antifungal treatment cacosmia and dysgeusia disappeared. HIV test was negative. Some studies presented that COVID-19 infection is linked with a continuous reduction in lymphocytes along the disease. We hypothesized that immunodeficiency in COVID-19 infection and antibiotic therapy could be the trigger for esophageal candidiasis in our case. ConclusionsOur case report highlighted the importance of smell and taste disorders DD, in COVID-19 pandemic. Dairy food cacosmia and dysgeusia can be a sign of esophageal candidiasis. That's why, convalescent COVID-19 infection patients should be monitored for a long-term period.

Our patient had allergic asthma that she was treating with inhaled corticosteroids. The immunosuppressive properties of corticosteroids could induce endogenous reactivation of latent HCMV.