J. S. Dumler

ankA: an Ehrlichia phagocytophila Group Gene Encoding a Cytoplasmic Protein Antigen with Ankyrin Repeats

ABSTRACT Human granulocytic ehrlichiosis (HGE) is a potentially fatal, tick-borne disease caused by a bacterium related or identical toEhrlichia phagocytophila. To identify and characterizeE. phagocytophila group-specific protein antigen genes, we prepared and screened HGE agent and Ehrlichia equi genomic DNA expression libraries using polyclonal equine E. equiantibodies. Two clones, one each from HGE agent and E. equi, that were recognized specifically by antibodies to theE. phagocytophila group ehrlichiae had complete open reading frames of 3,693 and 3,615 nucleotides, respectively. The two clones were 96.6% identical and predicted a protein with at least 11 tandemly repeated ankyrin motifs. Thus, the gene was namedank (for ankyrin). When the encoded protein, named AnkA, was expressed in Escherichia coli, it was recognized by antibodies from rabbits and mice immunized with the HGE agent, sera from humans convalescent from HGE, and sera from horses convalescent from HGE and E. equi infection. Monospecific AnkA antibodies reacted with proteins in HGE agent immunoblots, and AnkA monoclonal antibodies detected cytoplasmic antigen in E. phagocytophila group bacteria and also detected antigen associated with chromatin in infected but not uninfected HL-60 cell cultures. These results suggest that this Ehrlichia protein may influence host cell gene expression.

Human granulocytic ehrlichiosis in Europe

attention by a family member after hearing a media report concerning HPS cases. No specimens from 1959 were available. Blood obtained from the man during 1994 was initially tested by the New Mexico Scientific Laboratory Division. He was found to be IgG positive for antibodies to SNV. This was later confirmed by the CDC. This individual’s illness suggests that hantaviruses have been in the western USA for at least 35 years. Reports from the Native American populations in the area of the outbreak would suggest that similar outbreaks occurred earlier in this century. Because HPS has no pathognomonic clinical signs, search of historical (pre-twentieth century) medical documents would prove futile in trying to discover retrospective cases from that era. Having surviving cases also allows investigators to follow long-term IgG antibody levels much more quickly than waiting for time to elapse in following current survivors of HPS. Because this individual is a survivor, we have a serum history that shows he is still producing IgG antibodies 35 years after the illness.

Serological evidence of human granulocytic ehrlichiosis in Norway

Human granulocytic ehriichoisis was first described in 1994. This tick-transmitted illness is increasingly recognized in the USA as well as in Europe in areas where ixodes ticks and Lyme borreliosis are endemic. Blood samples from 58 Norwegian patients with physician-diagnosed Lyme borreliosis were examined for the presence of antibodies to Ehrlichia equi, a surrogate marker of the agent of human granulocytic ehrlichiosis. The results indicated that 10.2% of the patients may have been co-infected with human granulocytic ehrlichiosis and Lyme borreliosis. Human granulocytic ehrlichiosis appears to be established in southern Norway.

Analysis of genetic identity of North American Anaplasma phagocytophilum strains by pulsed-field gel electrophoresis.

ABSTRACT Biological and geographic heterogeneity of anthropozoonosis caused by Anaplasma phagocytophilum is poorly understood. Seven North American A. phagocytophilum strains were compared by PFGE. The average genome size was 1.58 Mbp, and restriction patterns were identical. New World strains of A. phagocytophilum have a large genome and a high degree of genetic uniformity.

Survey of laboratory-acquired infections around the world in biosafety level 3 and 4 laboratories

Laboratory-acquired infections due to a variety of bacteria, viruses, parasites, and fungi have been described over the last century, and laboratory workers are at risk of exposure to these infectious agents. However, reporting laboratory-associated infections has been largely voluntary, and there is no way to determine the real number of people involved or to know the precise risks for workers. In this study, an international survey based on volunteering was conducted in biosafety level 3 and 4 laboratories to determine the number of laboratory-acquired infections and the possible underlying causes of these contaminations. The analysis of the survey reveals that laboratory-acquired infections have been infrequent and even rare in recent years, and human errors represent a very high percentage of the cases. Today, most risks from biological hazards can be reduced through the use of appropriate procedures and techniques, containment devices and facilities, and the training of personnel.