GranulocyticEhrlichiainfection in Ixodid ticks and mammals in woodlands and uplands of the U.K.

Abstract

The prevalence of infection with Ehrlichiae of the Ehrlichia phagocytophila genogroup (the granulocytic Ehrlichiae), in questing Ixodes ricinus ticks of U.K. upland and woodland habitats, was investigated by PCR. The prevalence of infection in the three feeding stages of I. ricinus indicated that granulocytic Ehrlichiae are transmitted transstadially with no, or inefficient, transovarial transmission. The presence of infected ticks in both habitats indicates that endemic cycles of granulocytic Ehrlichia (GE) infection are maintained by both domesticated sheep and by wild reservoirs, and coexist with endemic cycles of Borrelia burgdorferi infection. Moreover, demonstration, for the first time, of GE infection in engorged Ixodes trianguliceps ticks and blood collected from wild rodents, suggests that European wild rodents are competent reservoirs. GE infection prevalence in nymphal and adult I. ricinus was significantly greater in uplands than woodlands, which is consistent with ticks of all three feeding stages feeding on reservoir-competent sheep in uplands. In one woodland studied, pheasants are important hosts for nymphal I. ricinus but are incompetent or inefficient reservoirs, so reducing GE infection prevalence in I. ricinus ticks in this habitat. 16S rRNA sequences of GE from ticks of these U.K. habitats, showed a high degree of homology with those of granulocytic Ehrlichiae isolated from humans, but also showed some evidence of genetic diversity of granulocytic ehrlichiae in the U.K. The implications of these findings, for the taxonomy of granulocytic ehrlichiae and the potential for human infections to occur in the U.K., is discussed.

Molecular and serological evidence of Anaplasma phagocytophilum infection of farm animals in the Black Sea Region of Turkey

“…Purified DNA samples were subjected to a nested PCR, modified from Barlough et al (1996) and Ogden et al (1998), targeting the 16S ribosomal RNA gene of A. phagocytophilum. Two pairs of oligonucleotide primers based on sequence data for the 16S rRNA gene of A. phagocytophilum (formerly E. phagocytophila, E. equi and HGE agent;Barlough et al, 1996;Chen et al, 1994;Petrovec et al, 1997; GenBank accession number: M73224, M73223 and U02521) were used.…”

“…The bacterium is transmitted by ixodid ticks and infects a wide range of species including domesticated ruminants (Gordon et al, 1932), equids (de la Fuente et al, 2005a), cats (Tarello, 2005), dogs (Poitout et al, 2005), wild animals (Skarphédinsson et al, 2005) and humans (Chen et al, 1994;Petrovec et al, 1997). In the United States the principal vectors are Ixodes scapularis and I. pacificus (Dumler, 1997), while in Europe the main exophilic tick vectors are I. ricinus and I. trianguliceps (Ogden et al, 1998). Rodents (Ogden et al, 1998), wild ruminants (Skarphédinsson et al, 2005) and domestic ruminants are potentially important reservoir hosts of A. phagocytophilum.…”

“…In the United States the principal vectors are Ixodes scapularis and I. pacificus (Dumler, 1997), while in Europe the main exophilic tick vectors are I. ricinus and I. trianguliceps (Ogden et al, 1998). Rodents (Ogden et al, 1998), wild ruminants (Skarphédinsson et al, 2005) and domestic ruminants are potentially important reservoir hosts of A. phagocytophilum. Migrating birds could also potentially play a role in dispersing Ehrlichia by carrying infected ticks from one country to another (Bjoersdorff et al, 2001).…”

Tropical and exotic infections

“…Interestingly, host immunity to ticks appears not to prevent transmission of granulocytic ehrlichiosis [158] as it does for Lyme disease [159]. E. phagocytophila genogroup ehrlichiae have been detected in I. scapularis in eastern and mid-west USA, in I. pacificus in California [160] and in I. ricinus and I. trianguliceps in UK [161] and Italy [162]. Ixodid ticks will feed on almost any vertebrate host and it is probable that the ecology of HGE in the USA involves a deer tick-rodent cycle [163].…”

Prevalence of Human-Active and Variant 1 Strains of the Tick-Borne Pathogen Anaplasma phagocytophilum in Hosts and Forests of Eastern North America

“…2,3 Anaplasmosis has also been documented throughout Europe and Asia. [4][5][6][7][8] Patients with anaplasmosis typically present with non-specific febrile symptoms, including fever, chills, headache, and myalgia, 9,10 particularly during summer months. 2,3 Most cases of anaplasmosis respond well to antibiotic treatment, but 17-56% of patients with anaplasmosis are hospitalized, and an estimated 1% of cases prove fatal.…”