PCR Detection of Mimivirus

T article by Zhang et al. (1) reporting the failure to detect mimivirus (Acanthamoeba polyphaga mimivirus) in patients with acute respiratory symptoms was flawed in 2 ways. First, a single mimivirus was detected by PCR but was dismissed by the authors as colonization. Second, and of greater concern, the PCR used by the authors would not detect most known mimiviruses because of primer/probe mismatches. In fact, PCRs used in most mimivirus prevalence studies would fail to detect most mimiviruses, given the extensive genome sequence diversity of these viruses (2). We evaluated the PCR primers/probes used by Zhang et al. (1) for sequence similarity with 51 mimivirus genomes available in the public domain since March 2016, the date on which the article by Zhang et al. was submitted (3). Our in silico analysis found that none of the 25 genomes available from lineage A and 7 genomes from lineage B were complementary with their primers and probes, and only 5 of 19 lineage C genomes showed sufficient sequence similarity to permit successful amplification (Table). Overall, the PCR used by these authors would be predicted to detect only ≈26% of lineage C mimiviruses and <10% of published mimivirus genomes overall. As proposed by Ngounga et al. (4), the great variability across the 3 lineages of mimivirus genomes requires the design of lineage-specific primers to improve PCR sensitivity (4). Until PCRs are improved, mimiviruses might be best detected by metagenomic approaches that have recently seen success in terms of mimivirus detection. For example, mimivirus-like reads have been identified by metagenomics in 1 (8%) of 12 fecal samples from children with acute diarrhea (5); 5 (27%) of 18 prostatic secretion samples from persons with prostatitis (6); all DNA libraries tested from the plasma of patients with hepatitis (7); 0.0018% of total viral reads from nasopharyngeal samples from 210 patients with respiratory tract symptoms (8); and all tested fecal, mid-vaginal, buccal mucosal, and retroauricular crease samples, with a predominance of mimiviruses in fecal samples reaching ≈33% of the total viral reads (9). In metagenomics approaches, the number of reads detected and the distribution along the whole viral genome

T he article by Zhang et al. (1) reporting the failure to detect mimivirus (Acanthamoeba polyphaga mimivirus) in patients with acute respiratory symptoms was flawed in 2 ways. First, a single mimivirus was detected by PCR but was dismissed by the authors as colonization. Second, and of greater concern, the PCR used by the authors would not detect most known mimiviruses because of primer/probe mismatches. In fact, PCRs used in most mimivirus prevalence studies would fail to detect most mimiviruses, given the extensive genome sequence diversity of these viruses (2).
We evaluated the PCR primers/probes used by Zhang et al. (1) for sequence similarity with 51 mimivirus genomes available in the public domain since March 2016, the date on which the article by Zhang et al. was submitted (3). Our in silico analysis found that none of the 25 genomes available from lineage A and 7 genomes from lineage B were complementary with their primers and probes, and only 5 of 19 lineage C genomes showed sufficient sequence similarity to permit successful amplification (Table). Overall, the PCR used by these authors would be predicted to detect only ≈26% of lineage C mimiviruses and <10% of published mimivirus genomes overall.
As proposed by Ngounga et al. (4), the great variability across the 3 lineages of mimivirus genomes requires the design of lineage-specific primers to improve PCR sensitivity (4). Until PCRs are improved, mimiviruses might be best detected by metagenomic approaches that have recently seen success in terms of mimivirus detection. For example, mimivirus-like reads have been identified by metagenomics in 1 (8%) of 12 fecal samples from children with acute diarrhea (5); 5 (27%) of 18 prostatic secretion samples from persons with prostatitis (6); all DNA libraries tested from the plasma of patients with hepatitis (7); 0.0018% of total viral reads from nasopharyngeal samples from 210 patients with respiratory tract symptoms (8); and all tested fecal, mid-vaginal, buccal mucosal, and retroauricular crease samples, with a predominance of mimiviruses in fecal samples reaching ≈33% of the total viral reads (9).
In metagenomics approaches, the number of reads detected and the distribution along the whole viral genome  A ngiostrongylus cantonensis is a rat lungworm that has long been recognized as a cause of eosinophilic meningitis in Southeast Asia, the Pacific Islands, and the Caribbean, where it is endemic (1). Although sporadic imported cases have been described in European travelers (2)(3)(4)(5), no autochthonous case of eosinophilic meningitis caused by A. cantonensis worms has been reported previously in metropolitan France.
A 54-year-old Moroccan woman was admitted to an emergency ward in Paris in 2016 because of fever and headache lasting 2 weeks. She had a history of type 2 diabetes treated with metformin and did not receive any other medication before the onset of symptoms. She was a pesco-vegetarian and worked as a cleaning woman in an office in Paris. She had taken up residence near Paris in the 1980s and had not traveled out of France since, except for Morocco over 2 years ago.
At admission, her blood pressure was 126/68 mm Hg, and her pulse was regular at 79 beats/min. The physical examination revealed meningeal signs with neck stiffness and photophobia without neurologic localization signs. No other clinical abnormality could be evidenced. Laboratory testing of serum showed a leukocyte count of 12.1 × 10 9 cells/L (reference range 4.5-11.0 × 10 9 /L) with 18% (2.2 × 10 9 cells/L) eosinophils and a C-reactive protein of 73 mg/dL (reference range 0.08-3.1 mg/L). Cerebrospinal fluid (CSF) analysis showed a leukocyte count of 950 cells/ µL with 56% eosinophils, a glucose concentration within reference range at 0.4 g/L, and an elevated protein level