False positive dengue NS1 antigen test in a traveller with an acute Zika virus infection imported into Switzerland.

We report the first case of an acute Zika virus infection imported into Switzerland by a traveller returning from Canoa Quebrada, Ceará state, in the north-eastern part of Brazil. Due to a false positive dengue virus NS1 antigen test, IgG antibody seroconversion and a suggestive clinical picture,an acute dengue fever was initially considered. However, because of lack of specific IgM-antibodies, stationary IgG antibody titre and a negative dengue virus PCR test result, a dengue virus infection was excluded and a cross-reaction with other, causative flaviviruses was postulated. Based on recent reports of Zika fever cases in the north-eastern parts of Brazil, an acute Zika virus infection was suspected. Because of a lack of commercially available Zika virus diagnostic tests, the case was confirmed in the WHO reference laboratory. As the clinical presentation of Zika virus infection can be confused with dengue fever and chikungunya fever, and because of possible public health implications, all patients returning from affected areas should be additionally tested for Zika virus. This case illustrates the urgent medical need for a broadly available assay capable of differentiating Zika from Dengue infections.

Human papillomavirus infection among women with cytological abnormalities in Switzerland investigated by an automated linear array genotyping test.

Limited data are available describing human papillomavirus (HPV) genotype distribution among females with cytological abnormalities in Switzerland. Cervical cell specimens obtained from 5,318 women were screened routinely by liquid-based Pap smear. All specimens with cellular abnormalities were analyzed subsequently for HPV DNA by the Linear Array HPV genotyping test. Cellular abnormalities were found in 202 (3.8%) specimens, of which 150 (74.3%) were positive for high-risk (HR) HPV. HR-HPV was detected in 20 (60.6%; 95% CI, 43.7-75.4%) of 33 specimens with atypical squamous cells of undetermined significance compared to 98 (72.1%; 95% CI, 64-78.9%) of 136 low-grade squamous intraepithelial lesions and 32 (97%; 95% CI, 83.4-99.9%) of 33 high-grade squamous intraepithelial lesions. The cumulative prevalence of HR-HPV other than HPV 16 and 18 was significantly higher than HPV 16 and/or 18 lesions with atypical squamous cells and low-grade lesions and was comparable in high-grade squamous intraepithelial lesions. The most common HR-HPV genotypes were HPV 16 (15.2%), HPV 31 (12.1%), HPV 58 (12.1%), HPV 51 (9.1%), and HPV 59 (9.1%) in women with atypical squamous cells, HPV 16 (25%), HPV 51 (16.9%), HPV 52 (11.8%), HPV 31 (9.6%), and HPV 56 (8.1%) in women with low-grade lesions (LSIL) and HPV 16 (57.6%), HPV 18 (18.2%), HPV 31 (15.2%), HPV 52 (12.1%), and HPV 58 (6.1%) in women with high-grade lesions (HSIL).

Automation of the linear array HPV genotyping test and its application for routine typing of human papillomaviruses in cervical specimens of women without cytological abnormalities in Switzerland.

BACKGROUND: There is a need for reliable, automated high throughput HPV detection and genotyping methods for pre- and post-prophylactic vaccine intervention analyses. OBJECTIVES: To optimize the linear array (LA) HPV genotyping test (Roche Diagnostics, Rotkreuz) in regard to possible automation steps for the routine laboratory diagnosis of HPV infections and to analyze the HPV genotype distribution in cervical specimens of women without cytological abnormalities in Switzerland. STUDY DESIGN: 680 cervical cell specimens with normal cytology, obtained from women undergoing routine cervical screening by liquid-based Pap smear, were analyzed by the LA HPV genotyping test for HPV-DNA. RESULTS: The automation of the LA HPV genotyping test resulted in a total hands-on time reduction of 255 min (from 480 to 225 min; 53%). Any of 37 HPV genotypes were detected in 117 (17.2%) and high-risk (HR) HPV in 55 (8.1%) of 680 women with normal cytology. The highest prevalence of any HPV (28.1%) and HR-HPV (15.1%) was observed in age-group 21-30 and showed a continuous decrease in older age-groups. The most common HR-HPV genotypes were HPV-16 (12%), HPV-31 (9.4%), HPV-52 (6%), HPV-51 (5.1%), HPV-45 (4.3%), HPV-58 (4.3%) and HPV-59 (4.3%). CONCLUSIONS: The optimization and automation of the LA HPV genotyping test makes it suited for high throughput HPV detection and typing. The epidemiological data provides information about distribution of HPV genotypes in women without cytological abnormalities in Switzerland and may be important for determining the future impact of vaccines and potential changes in the country's epidemiological HPV profile.

Rickettsia helvetica in Dermacentor reticulatus ticks.

We report on the molecular evidence that Dermacentor reticulatus ticks in Croatia are infected with Rickettsia helvetica (10%) or Rickettsia slovaca (2%) or co-infected with both species (1%). These findings expand the knowledge of the geographic distribution of R. helvetica and D. reticulatus ticks.

Persistent parvovirus B19 infection and arthralgia in a patient mistakenly treated for Lyme disease.

We report a case of a 37-year-old woman with persistent parvovirus B19 infection and arthralgia mistakenly treated for Lyme disease. This case indicates that poor standardization of both screening and confirmatory assays for Lyme disease can lead to an incorrect diagnosis of Lyme disease. Before making a final diagnosis of Lyme arthritis in an endemic region, other causative agents of arthritis, such as parvovirus B19, should be excluded to avoid unnecessary treatment or to add appropriate therapy in the case of co-infections. Since parvovirus B19 is often associated with arthralgia and can mimic rheumatoid arthritis and autoimmune diseases, it should be included in the differential diagnosis of arthralgia.

Serology and serum DNA detection in shingles.

AIM: To investigate the sensitivity of various laboratory approaches in the diagnosis of herpes zoster from patient serum. METHODS: Paired sera from 53 consecutive adult patients with acute herpes zoster were tested for the presence of varicella-zoster virus (VZV) antibodies. All acute sera were tested subsequently by real-time polymerase chain reaction (PCR) for the presence of VZV DNA. In addition, convalescent sera of patients who tested initially positive for VZV DNA underwent PCR analysis. RESULTS: VZV IgM antibodies were found by enzyme immunoassay (EIA) in 5 acute (9%) and 20 convalescent (38%) zoster sera. VZV DNA was detected by PCR in 21 (40%) acute zoster sera and was no longer detectable in the convalescent samples. A seroconversion or a fourfold or greater titre increase was found by complement fixation (CF) test in 41 (77%), by IgG indirect fluorescent antibody assay (IgG IFA) in 43 (81%) and by CF and IgG IFA combined in 45 of 53 (85%) paired zoster sera. The combination of all serological methods detected 51 (96%) and PCR combined with serology identified 52 (98%) of 53 patients. CONCLUSIONS: Optimal laboratory sensitivity in the diagnosis of herpes zoster from serum can be achieved by the combination of PCR and serology of paired serum samples. Serological methods alone are of limited value for early diagnosis of zoster when therapy can be initiated, because CF and IgG IFA need convalescent serum and IgM test sensitivity is insufficient. Early diagnosis of VZV reactivation is possible from serum by PCR in the first days of illness and test sensitivity needs further improvement. The findings highlight the need for future studies into the usefulness of PCR and serology in atypical cases of VZV reactivation.

A multiplex PCR assay for the detection of respiratory bacteriae in nasopharyngeal smears from children with acute respiratory disease.

To elucidate the frequency of infections with pathogenic respiratory bacteriae during an inter-epidemic period a multiplex PCR assay was used to screen nasopharyngeal smears for the presence of DNA specific for Bordetella pertussis, Bordetella parapertussis, Chlamydophila pneumoniae and Mycoplasma pneumoniae. 187 samples from children aged 2-14 y were analysed with this method in addition to classical bacteriology and compared to results obtained with commercially available PCR kits for each single parameter. From 82 samples positive by bacteriology, 8 (4.3%) were also positive by PCR, whereas from 105 negative samples, 12 (6.4%) were positive only by PCR. From the total of 20 samples positive by PCR, 4 were found to be positive for M. pneumoniae, 6 for B. pertussis, 3 for B. parapertussis and 7 for both B. pertussis and B. parapertussis. Multiplex PCR is a very useful approach for the diagnosis of bacterial infections not detectable by classical bacteriology. In some patients, PCR was the only method giving a positive result, and in others double infections were diagnosed only because of the PCR contribution. Combination of classical bacteriology with multiplex PCR allows a precise diagnosis of infections in the upper respiratory tract, resulting in a more effective therapy.

Prolonged parvovirus b19 viremia in spite of neutralizing antibodies after erythema infectiosum in pregnancy.

OBJECTIVE: To check the clearance of parvovirus B19 in the course of the development of neutralizing antibodies after Erythema infectiosum in pregnancy. METHODS: Parvovirus B19 serology (Parvovirus B19 IFA IgG, IgM Antibody Test Kit, Biotrin, Ireland and Immunoblot RIDA Blot Parvovirus B19, R-Biopharm, Germany) and polymerase chain reaction (PCR Parvovirus B19, Roche Diagnostics, Switzerland) were performed in eight predelivery sera, one cord blood sample and one serum 2 months after delivery. RESULTS: Acute parvovirus B19 infection in pregnancy was diagnosed by seroconversion in the IgM and IgG antibody class and detection of viral DNA by PCR. Despite the presence of neutralizing antibodies, PCR gave positive results in all subsequent sera including the cord blood sample and the post-delivery sample 7 months after primary infection. Neonatal examination on the 4th day after delivery was normal and no clinical sign of intrauterine infection was noted. CONCLUSIONS: Prolonged parvovirus B19 viremia infection can be seen in spite of neutralizing IgG antibodies and in IgM negative patients. Therefore, the presence of IgG antibodies in the absence of IgM antibodies should not always be interpreted as a past infection. The infectivity of patients with persistent parvovirus B19 infection requires further studies.