Assessment of African Swine Fever Diagnostic Techniques as a Response to the Epidemic Outbreaks in Eastern European Union Countries: How To Improve Surveillance and Control Programs.

This study represents a complete comparative analysis of the most widely used African swine fever (ASF) diagnostic techniques in the European Union (EU) using field and experimental samples from animals infected with genotype II ASF virus (ASFV) isolates circulating in Europe. To detect ASFV, three different PCRs were evaluated in parallel using 785 field and experimental samples. The results showed almost perfect agreement between the Universal ProbeLibrary (UPL-PCR) and the real-time (κ = 0.94 [95% confidence interval {CI}, 0.91 to 0.97]) and conventional (κ = 0.88 [95% CI, 0.83 to 0.92]) World Organisation for Animal Health (OIE)-prescribed PCRs. The UPL-PCR had greater diagnostic sensitivity for detecting survivors and allows earlier detection of the disease. Compared to the commercial antigen enzyme-linked immunosorbent assay (ELISA), good-to-moderate agreement (κ = 0.67 [95% CI, 0.58 to 0.76]) was obtained, with a sensitivity of 77.2% in the commercial test. For ASF antibody detection, five serological methods were tested, including three commercial ELISAs, the OIE-ELISA, and the confirmatory immunoperoxidase test (IPT). Greater sensitivity was obtained with the IPT than with the ELISAs, since the IPT was able to detect ASF antibodies at an earlier point in the serological response, when few antibodies are present. The analysis of the exudate tissues from dead wild boars showed that IPT might be a useful serological tool for determining whether or not animals had been exposed to virus infection, regardless of whether antibodies were present. In conclusion, the UPL-PCR in combination with the IPT was the most trustworthy method for detecting ASF during the epidemic outbreaks affecting EU countries in 2014. The use of the most appropriate diagnostic tools is critical when implementing effective control programs.

Protease inhibitor-resistant HIV-1 from patients with preserved CD4 cell counts is cytopathic in activated CD4 T lymphocytes.

OBJECTIVE: To evaluate CD4 T-cell cytopathicity of protease inhibitor (PI)-resistant isolates from patients with preserved CD4 cell counts after long-term virologic failure. METHODS: PI-resistant primary isolates from 14 patients with stable or increasing CD4 T-cell counts despite long-term virologic failure during continuous combination therapy were examined. Replication and cytopathicity were assessed in activated peripheral blood mononuclear cell cultures in the presence and absence of PI using titered stocks of primary HIV-1 isolates and during initial viral isolation. Also studied were PI-sensitive isolates from four of these patients after therapy discontinuation and reversion to PI-sensitive virus and from seven antiretroviral drug-naive patients. Coreceptor use, syncytia-inducing (SI) phenotype and protease sequences were determined by standard methods. RESULTS: All isolates obtained during continued therapy showed genetic markers of PI resistance and decreased phenotypic susceptibility. PI-resistant SI isolates were highly to moderately cytopathic whereas non-syncytia-inducing isolates were moderately to weakly cytopathic. PI-susceptible and PI-resistant isolates obtained after discontinuation of therapy were equally cytopathic at similar replication levels. The cytopathicity of PI-resistant isolates was not altered by PI and was similar to that of isolates from untreated subjects. CONCLUSIONS: Primary isolates from patients showing virologic rebound without net CD4 T-cell loss during continued therapy are as cytopathic as PI-sensitive isolates with equivalent input infectious titer. As with PI-sensitive isolates, cytopathicity of PI-resistant viruses was determined primarily by coreceptor preference. These results suggest that the sustained immunologic response observed after failure of PI-containing regimens is not due to the emergence of PI-resistant strains that are intrinsically less cytopathic for activated peripheral CD4 lymphocytes.