Seroprevalence of ehrlichia canis antibodies among dogs in Turkey

Canine monocytic ehrlichiosis (CME) is a potentially fatal tickborne disease caused by the rickettsia Ehrlichia canis. Its principal vector is the brown dog tick Rhipicephalus sanguineus. The distribution of CME is directly related to the distribution of this vector, and most cases occur during the warm season when the tick is active (Harrus and others 1997, Leib and Monroe 1997). The disease has been reported in Asia, Africa, Europe and America. Serosurveys conducted in Egypt, Israel, Germany and France have revealed 33, 30,25·1 and 9 to 12 per cent E canis antibody seroprevalence, respectively (Davoust 1994, Botros and others 1995, Baneth and others 1996, Gothe 1998). The pathogenesis of CME involves an incubation period of eight to 20 days, followed by acute, subclinical and, in some cases, chronic phases (Waner and others 1997). The disease may manifest in a wide variety of clinical signs, of which fever, anorexia, weight loss, depression, lymphadenomegaly, splenomegaly and platelet-related bleeding are predominant (Harrus and others 1997, Leib and Monroe 1997, Kontos and Athanasiou 1998). Most cases of CME are diagnosed by serological testing. Antibodies against E canis are detected circulating in the serum of infected animals by the indirect immunofluorescent antibody (IFA) test, dot-ELISA and Western blot immunoassay (Waner and others 1996, Harrus and others 1997). The aim of this study was to investigate the seroprevalence of E canis antibodies among dogs in Turkey, and to characterise the first 20 serologically confirmed clinical cases of CME that were admitted to the Faculty of Veterinary Medicine in Bursa, Turkey. Blood was taken from 284 dogs (164 males and 120 females, comprising 124 crossbred dogs, 133 pure breeds [ 19 different breeds] and 27 unknown breeds) from three different geographical and climatic regions in Turkey: 143 samples from Bursa and 38 samples from Balikesir in the Marmara region, 32 samples from Izmir in the Agean region, and 27 samples from Şanliurfa, 26 samples from Adana and 18 samples from Antalya in southern Turkey. In Bursa, all blood samples were collected from dogs that were presented to the small animal clinic of the Faculty of Veterinary Medicine, University of Uludağ, Bursa, for a general health check and vaccination, or due to illness. The samples from the other cities were collected from clinically healthy kennel dogs. Samples were collected between October 1997 and November 1998. Serum samples were separated off by centrifugation for serological testing, and kept frozen at -20°C until shipped in an iced container to the Laboratory of Infectious Diseases of the School of Veterinary Medicine, the Hebrew University of Jerusalem, in Israel. Serology was performed using the IFA test as described by Ristic and others (1972). The test was performed on slides prepared with acetone-fixed heavily infected cells (dog macrophage cell line DH82), with the local Israeli isolate of E canis (Keysary and others 1996). Two-fold serum dilutions (5 μl) were added to wells, and slides were incubated in a humidified chamber at 37°C for 30 minutes. Known positive and negative controls were used on each slide. The slides were then washed gently with phosphate buffered saline (PBS), air dried and 5 μl of rabbit anti-dog immunoglobulin G-fluorescein isothiocyanate conjugate solution (Sigma) 1:20 in PBS, was added to each well. After further incubation at 37°C for 30 minutes, the slides were washed, air dried and examined under a fluorescence microscope. A titre of 1:40 or greater was considered to be positive. In addition, the clinical and clinical pathological findings of 20 dogs suffering from clinical CME (confirmed by serology) that were admitted to the University of Uludağ, Bursa, were reviewed. Blood samples with an anticoagulant ethylenediamine tetra-acetic acid were taken from the 20 dogs, and complete blood counts were performed by an autoanalyser (Serono). The dogs were treated with 10 mg/kg doxycycline (Tetradox; Fako), once daily for 21 days, or 5 mg/kg enrofloxacin (Baytril; Bayer) every 12 hours for 21 days

Comparison of Simultaneous Splenic Sample PCR with Blood Sample PCR for Diagnosis and Treatment of Experimental Ehrlichia canis Infection

This report presents evidence that dogs recover from acute canine monocytic ehrlichiosis (CME) after 16 days of doxycycline treatment (10 mg/kg of body weight every 24 h). Blood PCR was as valuable as splenic aspirate PCR for early diagnosis of acute CME. Splenic aspirate PCR was, however, superior to blood PCR for the evaluation of ehrlichial elimination

TLR3 and TLR9 agonists improve postexposure vaccination efficacy of live smallpox vaccines.

Eradication of smallpox and discontinuation of the vaccination campaign resulted in an increase in the percentage of unvaccinated individuals, highlighting the need for postexposure efficient countermeasures in case of accidental or deliberate viral release. Intranasal infection of mice with ectromelia virus (ECTV), a model for human smallpox, is curable by vaccination with a high vaccine dose given up to 3 days postexposure. To further extend this protective window and to reduce morbidity, mice were vaccinated postexposure with Vaccinia-Lister, the conventional smallpox vaccine or Modified Vaccinia Ankara, a highly attenuated vaccine in conjunction with TLR3 or TLR9 agonists. We show that co-administration of the TLR3 agonist poly(I:C) even 5 days postexposure conferred protection, avoiding the need to increase the vaccination dose. Efficacious treatments prevented death, ameliorated disease symptoms, reduced viral load and maintained tissue integrity of target organs. Protection was associated with significant elevation of serum IFNα and anti-vaccinia IgM antibodies, modulation of IFNγ response, and balanced activation of NK and T cells. TLR9 agonists (CpG ODNs) were less protective than the TLR3 agonist poly(I:C). We show that activation of type 1 IFN by poly(I:C) and protection is achievable even without co-vaccination, requiring sufficient amount of the viral antigens of the infective agent or the vaccine. This study demonstrated the therapeutic potential of postexposure immune modulation by TLR activation, allowing to alleviate the disease symptoms and to further extend the protective window of postexposure vaccination

\u3cem\u3eRickettsia africae\u3c/em\u3e and \u3cem\u3eCandidatus\u3c/em\u3e Rickettsia barbariae in Ticks in Israel

DNA of several spotted fever group rickettsiae was found in ticks in Israel. The findings include evidence for the existence of Rickettsia africae and CandidatusRickettsia barbariae in ticks in Israel. The DNA of R. africae was detected in aHyalomma detritum tick from a wild boar and DNA of C. Rickettsia barbariae was detected in Rhipicephalus turanicus and Rhipicephalus sanguineuscollected from vegetation. The DNA of Rickettsia massiliae was found in Rh. sanguineus and Haemaphysalis erinacei, whereas DNA of Rickettsia sibirica mongolitimonae was detected in a Rhipicephalus (Boophilus) annulatus. Clinicians should be aware that diseases caused by a variety of rickettsiae previously thought to be present only in other countries outside of the Middle East may infect residents of Israel who have not necessarily traveled overseas. Furthermore, this study reveals again that the epidemiology of the spotted fever group rickettsiae may not only involve Rickettsia conorii but may include other rickettsiae

Genetic and Antigenic Diversities of Major Immunoreactive Proteins in Globally Distributed Ehrlichia canis Strains▿

The extent of knowledge regarding the diversity of globally distributed Ehrlichia canis strains has been limited to information gained from a few evolutionarily conserved genes. In this study, E. canis strains from the United States (strain Jake [US]), Brazil (strain São Paulo [BR]), and Israel (strain 611 [IS] and Ranana [IS-R]) were used to examine the antigenic and genetic diversities of four well-characterized major immunoreactive protein genes/proteins. gp36 and gp200 were the most divergent genes, and nucleotide substitutions in the gp36 tandem repeat region of the IS strain, but not the IS-R strain, resulted in two amino acid differences (S→P and P→T) in each nine-amino-acid repeat (epitope-containing region). DNA sequences of gp19 and gp140 were completely conserved in the US and BR strains, but differences were found in the Israeli strains, including two fewer tandem repeats in gp140 and a single amino acid substitution in gp19 from the IS strain. E. canis whole-cell lysates from each isolate were examined by Western immunoblotting using sera from naturally infected dogs from each country, and four major immunoreactive proteins (gp19, gp36, gp140, and gp200) were identified in each strain using protein-specific antisera. The US and BR strains exhibited highly conserved immunoreactive protein profiles, while some differences were identified in the IS strain. Sera from naturally infected Israeli dogs confirmed gene sequencing information, which demonstrated two distinct E. canis strains, defined by the gp36 gene. Conversely, gp19 was strongly reactive and present in all E. canis isolates. gp140 and gp200 were also present in all strains, although gp140 in the IS strain had two fewer tandem repeats and exhibited a smaller mass