Clinical and Applied Virology, Infectious Diseases Research Unit, Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-sur-Alzette, Luxembourg
Dr. Judith M. Hübschen
Clinical and Applied Virology, Infectious Diseases Research Unit, Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-sur-Alzette, Luxembourg
A critical component of laboratory surveillance for measles is the genetic characterization of circulating wild-type viruses. The World Health Organization (WHO) Measles and Rubella Laboratory Network (LabNet), provides for standardized testing in 183 countries and supports genetic characterization of currently circulating strains of measles viruses. The goal of this report is to describe the lessons learned from nearly 20 years of virologic surveillance for measles, to describe the global databases for measles sequences, and to provide regional updates about measles genotypes detected by recent surveillance activities. Virologic surveillance for measles is now well established in all of the WHO regions, and most countries have conducted at least some baseline surveillance. The WHO Global Genotype Database contains >7000 genotype reports, and the Measles Nucleotide Surveillance (MeaNS) contains >4000 entries. This sequence information has proven to be extremely useful for tracking global transmission patterns and for documenting the interruption of transmission in some countries. The future challenges will be to develop quality control programs for molecular methods and to continue to expand virologic surveillance activities in all regions.
We conducted a phylogenetic analysis of 19 hepatitis B virus strains from Laos that belonged to 2 subgenotypes of a new genotype I. This emerging new genotype likely developed outside Southeast Asia and is now found in mixed infections and in recombinations with local strains in a geographically confined region.
1 May 2010 in Applied and Environmental Microbiology
In Europe, ixodid ticks are important arthropod vectors of human and animal pathogens, but comprehensive studies of the prevalence of all relevant pathogens in Central Europe are scarce. As a result of ecological changes, the incidences of tick-borne infections are expected to increase. In this study, 1,394 nymphal and adult Ixodes ricinus ticks sampled monthly during the active season from 33 ecologically distinct collection sites throughout Luxembourg were screened for all human tick-borne pathogens relevant in Central Europe. Species were identified by sequence analysis of detection PCR amplicons. Mean infection rates of ticks were 11.3% for Borrelia burgdorferi sensu lato, 5.1% for Rickettsia sp., 2.7% for Babesia sp., and 1.9% for Anaplasma phagocytophilum . No tick was found to be infected with Coxiella sp., Francisella tularensis subsp., or Tick-borne encephalitis virus (TBEV). A total of 3.2% of ticks were infected with more than one pathogen species, including mixed Borrelia infections (1.5%). Seasonal variations of tick infection rates were observed for Borrelia , Babesia , and Anaplasma , possibly reflecting a behavioral adaptation strategy of questing ticks. A positive correlation between the grade of urbanization and Borrelia infection rate of ticks was observed, suggesting an established urban zoonotic cycle. We also found Hepatozoon canis (0.1%) and Bartonella henselae (0.3%), which so far have not been found in questing Ixodes ricinus ticks in Central Europe.
15 April 2012 in Applied and Environmental Microbiology
Ticks are important disease vectors that can cause considerable economic losses by affecting animal health and productivity, especially in tropical and subtropical regions. In this study, we investigated the prevalence and diversity of bacterial and protozoan tick-borne pathogens in ticks collected from the vegetation and cattle in Nigeria by PCR. The infection rates of questing ticks were 3.1% for Rickettsia species, 0.1% for Coxiella burnetii and 0.4% for Borrelia species. Other pathogens, such as Babesia , Theileria , Anaplasma , and Ehrlichia species, were not detected in ticks from the vegetation. Feeding ticks collected from cattle displayed infection rates of 12.5% for Rickettsia species, 14% for Coxiella burnetii , 5.9% for Anaplasma species, 5.1% for Ehrlichia species, and 2.9% for Theileria mutans. Babesia and Borrelia species were not detected in ticks collected from cattle. Mixed infections were found only in feeding ticks and mainly Rickettsia species and Coxiella burnetii were involved. The diversity of tick-borne pathogens in Nigeria was higher in feeding than in questing ticks, suggesting that cattle serve as reservoirs for at least some of the pathogens studied, in particular C. burnetii . The total estimated herd infection rates of 20.6% for a Rickettsia africae -like species, 27% for Coxiella burnetii , and 8.5% for Anaplasma marginale/centrale suggest that these pathogens may have considerable implications for human and animal health.