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.Canine monocytic ehrlichiosis (CME) is a tick-borne disease with a global distribution (9). Diagnosis of CME is confirmed by demonstration of morulae in blood smears, serology, culturing of the rickettsiae, and PCR using Ehrlichia canis-specific primers. Tetracyclines are commonly used in the treatment of CME, with doxycycline in particular being the most acceptable and widely used (2, 3).Blood samples are presently used for PCR evaluation of ehrlichial infection and response to therapy (15). A previous study has demonstrated ehrlichial DNA in splenic aspirates of two subclinically experimentally infected dogs whose blood and bone marrow aspirates were found to be negative for E. canis DNA, suggesting the importance of splenic aspirates in the diagnosis of ehrlichial carriers (6). This finding questioned the validity of previous blood-based PCR studies for evaluating treatment regimens for CME, and the length of doxycycline treatment required for E. canis infection remained uncertain.The aims of this study were (a) to investigate whether splenic aspirates are superior to blood samples as a sample source for E. canis PCR; (b) to determine whether dogs with acute CME remain persistently infected despite concurrent treatment; and (c) to determine the duration of doxycycline treatment required to eliminate E. canis DNA, as measured by PCR in cases of acute CME.Five beagle dogs, 4 to 6 years old and negative serologically and by PCR for E. canis, were used in this study. The dogs were artificially infected by intravenous injection of 5 ml of E. canisinfected blood. This blood was drawn from an acutely ill, naturally infected dog. Infection of the donor dog with E. canis was confirmed by serology using the indirect immunofluorescence antibody (IFA) test (11), by blood culture of DH82 cells (4), and by p30-based nested PCR for E. canis (14).

SummaryThe tick Ixodes ricinus is responsible for the transmission of a number of bacterial, protozoan and viral diseases to humans and animals in Europe and š Č ȇ Northern Africa. Female I. ricinus from England, Switzerland and Italy have been found to harbour an intracellular a-proteobacterium, designated IricES1, within the cells of the ovary. IricES1 is the only prokaryote known to exist within the mitochondria of any animal or multicellular organism. To further examine the distribution, prevalence and mode of transmission of IricES1, we performed polymerase chain reaction screening of I. ricinus adults from 12 countries across its geographic distribution, including tick colonies that have been maintained in the laboratory for varying periods of time. IricES1 was detected in 100% of field-collected female ticks from all countries examined (n = 128), while 44% of males were found to be infected (n = 108). Those males that are infected appear to harbour fewer bacteria than females. Sequencing of fragments of the 16S rRNA and gyrB genes revealed very low nucleotide diversity among various populations of IricES1. Transmission of IricES1 from engorged adult females to eggs was found to be 100% (n = 31). In tick colonies that had been maintained in the laboratory for several years, a relatively low prevalence was found in females (32%; n = 25). To our knowledge, IricES1 is the most widespread and highly prevalent of any tick-associated symbiont.

GM1-ganglioside receptor binding by the B subunit of cholera toxin (CtxB) is widely accepted to initiate toxin action by triggering uptake and delivery of the toxin A subunit into cells. More recently, GM1 binding by isolated CtxB, or the related B subunit of Escherichia coli heat-labile enterotoxin (EtxB), has been found to modulate leukocyte function, resulting in the down-regulation of proinflammatory immune responses that cause autoimmune disorders such as rheumatoid arthritis and diabetes. Here, we demonstrate that GM1 binding, contrary to expectation, is not sufficient to initiate toxin action. We report the engineering and crystallographic structure of a mutant cholera toxin, with a His to Ala substitution in the B subunit at position 57. Whereas the mutant retained pentameric stability and high affinity binding to GM1-ganglioside, it had lost its immunomodulatory activity and, when part of the holotoxin complex, exhibited ablated toxicity. The implications of these findings on the mode of action of cholera toxin are discussed.

The delivery of certain living microorganisms in food has long been suggested as having positive health effects in humans. This practice has extended into food animal production, with a variety of microorganisms being used; lactic acid bacteria, variousBacillusspecies and the yeastSaccharomyces cerevisiaehave been particularly used in the pig industry. The increased interest in probiotics is essentially due to the problem of microbial resistance to antibiotics and following the ban of the use of antibiotics in animal production, probiotics being considered an alternative means to reduce pathogen infection and improve animal health especially around the time of weaning. However, there is still a need to clarify the probiotic effectiveness in pigs, and the underlying mechanisms. When assessing the efficacy of probiotics one must consider the particular strain of organism being used and the production stage of the pigs being treated. The reproducible delivery of probiotics in industrial pig production is problematic as maintenance of viability is key to their beneficial activity, but difficult to achieve with commonly used feed processing technologies. One specific context where probiotics organisms may be reliably delivered is in systems utilising fermented liquid feeds. Liquid feed may be fermented by the activity of wild lactic acid bacteria or may be stimulated using specific isolates as ‘starters’; the latter system has advantages in terms of reproducibility and speed of fermentation. The farm context in which the organism is used is likely to be critical; the use of probiotics is more likely to result in measurable economic gains in animals living in sub-optimal conditions rather than in those reared in the highest welfare and husbandry conditions. The establishment of a beneficial lactic acid bacteria population at birth may lead to healthier animals, this may be most effectively achieved by treating sows, which provide an amplification step and flood the neonatal pigs’ environment with desirable bacterial strains. In contrast, it may be sufficient to provide a supportive, protective microbiota around the time of weaning as this is a time of major crisis with instability and loss of certain bacterial populations.

In North America it has been shown that distinct hemotropic mycoplasmas exist in dogs. Blood samples from 460 French dogs were analyzed by PCR to evaluate hemoplasma infection status. Seventy-one dogs (15.4%) were positive; of these, 44 (9.6%) were infected with an organism closely related to "Candidatus Mycoplasma haemoparvum" only, 15 (3.3%) were infected with Mycoplasma haemocanis only, and 12 dogs (2.6%) were dually infected with both organisms.

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Parasitemia with a large Babesia species was identified in two domestic cats from Israel. One cat, also coinfected with feline immunodeficiency virus and "Candidatus Mycoplasma haemominutum," had profound icterus and anemia which resolved after therapy, whereas a second cat was an asymptomatic carrier. Amplification and sequencing of the 18S rRNA gene, followed by phylogenetic analyses, indicated that infection was caused by Babesia canis. However, the sequences of the internal transcribed and 5.8S rRNA regions of the ribosomal operon used for subspeciation of B. canis were markedly different from the recognized subspecies of B. canis, which include B. canis vogeli, B. canis canis, and B. canis rossi. Based on phylogenetic comparisons of the 18S rRNA gene, 5.8S, and internal transcribed spacer sequences of the isolates from the cats and on the smaller sizes of the merozoite and trophozoite stages of this parasite, which distinguish it from the subspecies of B. canis present in dogs, we propose to identify the novel feline genotype of B. canis described in the present study as a new subspecies, B. canis subsp. presentii.Babesia species are tick-borne intraerythrocytic apicomplexan parasites found in a variety of domestic and wild animals and in humans. Babesiosis in domestic cats has primarily been reported in South Africa, where infection is mainly due to Babesia felis, a small Babesia that causes anemia and icterus (24,28). In addition, Babesia cati was reported from a cat (Felis catus) in India (23) and sporadic cases of infection in domestic cats by unidentified Babesia parasites have been reported in France, Germany, Thailand, and Zimbabwe (3,16,22,29). Reports of Babesia in wild felids include Babesia herpailuri from a jaguarundi (Herpailurus yaguarundi) (7), Babesia pantherae from a leopard (Panthera pardus) (8), Babesia leo from lions (Panthera leo) (24), and a unidentified piroplasm in cheetahs (Acinonyx jubatus) (1). Cytauxzoon felis is a piroplasm that is phylogenetically related to Theileria and Babesia and infects the bobcat (Lynx rufus) (11) and domestic cats (34). In a recent study from Spain and Portugal, a partial DNA sequence from the small subunit RNA gene identified as Babesia canis canis was amplified from the blood of three cats in which parasites were not visualized by microscopy (6). This has provided initial molecular evidence for infection by Babesia canis in cats.Babesia infections in domestic dogs are caused by large piroplasms described as B. canis and by smaller parasites that are mostly grouped under the species Babesia gibsoni. Three subspecies of B. canis have been recognized based on differences in the pathological and clinical syndromes caused by each subspecies, antigenic properties, transmission by different vector ticks, and genetic characterization (5,13,27,36). B. canis rossi described in South Africa is transmitted by the tick Haemaphysalis leachi and causes a severe and often fatal hemolytic disease in dogs (25). B. canis vogeli is found in the Middle East, North Africa, ...

PCR analysis was used to determine the prevalence of tick-transmitted infections in 120 systemically ill dogs and 60 cats recruited over a period of three months from 52 veterinary practices in the UK. The animals had not travelled outside the UK and had one or more of the following clinical criteria: acute or recurrent pyrexia, anaemia and/or thrombocytopenia, polyarthritis/muscle pain, splenomegaly/lymphadenopathy, and intraocular inflammation with systemic signs. Blood samples from the animals were tested for the presence of DNA from Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum by using simple PCR targeting. B. burgdorferi sensu lato was detected in five dogs and two cats, and A. phagocytophilum was detected in one dog and one cat. These results provide the first molecular evidence of naturally occurring B. burgdorferi sensu lato infection in cats in the UK and confirm that A. phagocytophilum infection is present in cats. There were no statistically significant associations between the infections and the clinical signs shown by the dogs and cats.