Toxocara spp. infections in paratenic hosts

The zoonotic roundworms Toxocara canis and T. cati are not only present worldwide in their definitive hosts; they also frequently occur in other animal species, including humans. In those so-called paratenic hosts, the larvae do not develop into the adult stage, but rather migrate throughout the somatic tissue and persist as infectious L3 stage for extensive periods. Those arrested larvae may lead to severe inflammatory reactions and consequently to a wide range of pathological and clinical manifestations. However, the infected paratenic hosts also constitute a potential source of infection for the definitive hosts or humans who may also function as paratenic hosts. In the present review, current knowledge of larval migration in a variety of possible paratenic hosts is summarized including variations of migration routes and susceptibilities. Furthermore, information about the clinical and pathological changes for the presented species and possible consequences of the somatic migration of larvae, i.e. the resulting tissue damage as well as adverse host reactions to arrested larvae are reviewed. There are still many questions unanswered regarding larval behaviour in hosts other than their definitive host. Therefore, it is of great importance to continue further elaboration on the biology of Toxocara spp. to prevent further spreading of larvae in both the paratenic and the definitive host.     

Timing of Puberty and Its Relationship with Body Growth and Season in Male Raccoons (Procyon lotor) in Hokkaido

The raccoon (Procyon lotor), indigenous to North America, has naturalized in Japan as an invasive alien species, having been introduced into the country in the 1970s. In Hokkaido, the northernmost island of Japan, feral raccoons have been increasing in number and spreading throughout the island. The age at the onset of puberty for raccoons is important for estimating individual lifetime reproductive success and population growth. The present study investigated the timing of and potential factors affecting the onset of puberty in male raccoons in Hokkaido. External characteristics and histology of testes were studied in 151 male feral raccoons and in 1 captive juvenile. For the majority of feral yearling raccoons, prepubertal development began in May, and spermatozoa production began in October prior to their second mating season. However, some larger juveniles attained puberty during the juvenile period. The captive juvenile, which was fed throughout the winter, attained puberty only 11 months after birth. These results suggest that if male raccoons can achieve enough body growth before the first mating season, puberty can be attained early. In both juveniles and yearlings, spermatozoa production was only observed after autumn. This timing coincided with the recrudescence of seasonally active spermatogenesis in adult males. Therefore, attaining puberty in male raccoons appears to require both adequate body nutrient development and several environmental factors that control seasonal testicular changes.     

Infections with Anaplasma phagocytophilum in dogs in Germany

The main objectives of this prospective study were to establish prevalence of Anaplasma phagocytophilum infections in dogs from Northeast Germany; and to evaluate the hematological parameters of sero- or real-time PCR-positive clinically healthy dogs. The mean prevalence of A. phagocytophilum seropositivity of 522 dogs (258 suspected to have anaplasmosis, 264 healthy) was 43%. There was no difference between sick (46.9%) and healthy dogs (39.8%) (p = 0.100). The PCR test was positive in 30 dogs (20 sick, 10 healthy); morulae were found in 12 of them. Twenty-six of 30 dogs tested PCR-positive between May and September (p < 0.05). There was no difference with regard to abnormal CBC parameters between seropositive and seronegative clinically healthy dogs. The CBC was within reference range in 10 PCR-positive clinically healthy dogs suggesting a routine examination of blood donors for A. phagocytophilum in endemic areas to minimize the risk of transmission.     

Cessation of clinical disease and spirochete shedding after tiamulin treatment in pigs experimentally infected with “Brachyspira hampsonii”

With the emergence of “Brachyspira hampsonii” associated with swine dysentery in North America, identification of effective treatments and interventions is a pressing need. Denagard® (tiamulin hydrogen fumarate) Liquid Concentrate 12.5% is approved in the United States for treatment of dysentery caused by Brachyspira hyodysenteriae at 0.006% in the water. In this study, the effectiveness of tiamulin in resolving clinical disease, eliminating viable spirochete shedding, and reducing neutrophilic colitis following infection with either “B. hampsonii” or B. hyodysenteriae was evaluated. Seventy-eight 7-week-old crossbred pigs were divided into three groups [sham-inoculated (n = 18), “B. hampsonii”-inoculated (n = 30), and B. hyodysenteriae-inoculated (n = 30)]. Each inoculum group was divided into three subgroups which received either 0.006% tiamulin, 0.018% tiamulin, or no medication. Both levels of tiamulin resolved clinical disease within 24 h of treatment initiation, eliminated spirochete shedding within 72 h of treatment initiation, and resolved and/or prevented histologic lesions in pigs infected with either Brachyspira spp.     

Prevalence and characterization of Staphylococcus aureus and Staphylococcus pseudintermedius isolated from companion animals and environment in the veterinary teaching hospital in Zambia,Africa

The Republic of Zambia consists of only one veterinary teaching school at the University of Zambia (UNZA) where students and veterinarians are exposed to many bacterial pathogens including Staphylococcus aureus (SA) and Staphylococcus pseudintermedius (SP). The aim of this study was the characterization and antimicrobial susceptibility profile of eleven SA and 48 SP isolates from the veterinary hospitals’ in- and outpatients and the environment. No isolate was resistant to cefoxitin by disk diffusion test and the corresponding resistance gene mecA was not found. In contrast, the resistance rates of SA to penicillin (63.6%) and trimethoprim-sulfamethoxazole (36.4%) and SP to penicillin (52.1%) and tetracycline (25.0%) were the highest. A variety of sequence types (STs) without a predominant type including numerous novel types were determined, especially for SP (39.6%). The spa typing provided a clonal assignment for all SAs (100%) and 24 SPs (50%) with three and two novel types, respectively. This study has provided an overview of SA and SP in the veterinary teaching hospital at UNZA. However, for a better understanding of these species regarding pathogenesis and transmission, further studies on the prevalence and characterization of SA and SP from veterinary staff, pet owners, and farm animals in Zambia is needed.     

A preliminary investigation of Ehrlichia species in ticks, humans, dogs, and capybaras from Brazil

A molecular epidemiologic investigation in two Brazilian states (Rondônia and São Paulo) was undertaken to determine if Ehrlichia species responsible for human and animal ehrlichioses in North America could be found in Brazilian vectors, potential natural mammalian reservoirs and febrile human patients with a tick bite history. Samples, including 376 ticks comprising 9 Amblyomma species, 29 capybara (Hydrochaeris hydrochaeris) spleens, 5 canine blood, and 75 human blood samples from febrile patients with history of tick bites were tested by a real-time PCR assay targeting a fragment of the Ehrlichia dsb gene. Ehrlichia DNA was not detected in any tick, capybara or human samples. In contrast, 4 out of 5 dogs contained Ehrlichia canis DNA in their blood, which were sequenced, representing the first report of E. canis infecting dogs in the Amazon region of Brazil. Further studies are needed to evaluate the presence of other agents of human and animal ehrlichioses in Brazil.     

Role of pet dogs and cats in the transmission of helminthic zoonoses in Europe, with a focus on echinococcosis and toxocarosis

The close emotional tie between people and companion animals is a beneficial relation known as the human-animal bond. However, pet dogs and cats can play an important role in the transmission of helminthic zoonotic agents such as the tapeworms Echinococcus and the roundworms Toxocara which are directly transmitted from pets to the human environment without the involvement of vectors or intermediate hosts. In humans, echinococcosis has emerged in Europe and toxocarosis is still persisting in large endemic areas despite the availability of highly efficient anthelminthics for dogs and cats. Ecological changes significantly contributed to these trends: the high wild fox populations and the high density of freely roaming dogs and cats maintain a permanent infection pressure of these and other parasites. Further, the establishment of urban recreational environments closer to natural ecological systems boosted vole populations that represent urban reservoirs for zoonotic helminths. A good understanding of the parasites’ biology and epidemiology including the transmission to humans is required for planning and implementing effective prevention strategies. The continuous education of veterinarians and the information of the pet owners by providing uniform recommendations are of priority importance. A close collaboration between veterinary and public health professionals in a ‘One Health’ concept is required.     

Molecular survey of Dirofilaria immitis and Dirofilaria repens by direct PCR for wild caught mosquitoes in the Republic of Korea

Adult mosquito collections using New Jersey light traps and Black-hole light traps were conducted to determine the potential vectors and the relative mosquito infection rates of Dirofilaria immitis and Dirofilaria repens in Gyeonggi and Gangwon Provinces, Republic of Korea, 2005. Dirofilaria spp. were confirmed by polymerase chain reaction (PCR) using species-specific primers for D. immitis and D. repens. Minimum field infection rates (MFIR) [MFIR = (number infected pools/total number of mosquitoes) x 1000] of 12 pools/2059 total number mosquitoes (5.8) and 21 pools (10.1) of the wild caught mosquitoes were positive by PCR for D. immitis and D. repens, respectively. Dual infections of both D. immitis and D. repens were detected by PCR in eight pools (3.9). Anopheles sinensis sensu lato (includes An. sinensis s.s., An. pullus, An. kleini, An. belenrae, and An. lesteri), An. sineroides, Aedes vexans nipponi, Culex pipiens and Armigeres subalbatus were found to be infected and are potential vectors of D. immitis and D. repens in Korea. Infections observed in mosquitoes represent potential health risks for domestic animal and human populations.     

Seroprevalence of antibodies to Encephalitozoon cuniculi and Encephalitozoon intestinalis in humans and animals

The presence of antibodies against Encephalitozoon cuniculi (E. cuniculi) and Encephalitozoon intestinalis (E. intestinalis) was examined in 215 samples from humans and in 488 samples from five different species of domestic and companion animals in Slovakia. The 215 human samples and samples from 90 swine, 123 non-infected cattle (cattle), 24 cattle infected with bovine leukosis virus (BLV-positive cattle), 140 sheep and 111 dogs were examined by the enzyme-linked immunosorbent assay (ELISA). Samples with serum titres 1:200 or higher were considered as positive. Specific anti-E. cuniculi antibodies were found in humans (0.9%), swine (52%), cattle (2%), sheep (9%) and dogs (15%) except for the BLV-positive cattle at the titre of 1:200. The titre of 1:400 was detected only in humans (0.5%). The presence of specific anti-E. intestinalis antibodies at the titre of 1:200 was confirmed in humans (6%), swine (51%), cattle (11%), BLV-positive cattle (13%) and dogs (6%) but not in sheep. The anti-E. intestinalis antibodies reached the 1:400 in humans (1%), swine (4%) and BLV-positive cattle (17%). The presence of specific anti-E. intestinalis antibodies at the titre of 1:600 was observed only in one swine (1%). Significant differences were observed in animals at titres 1:200 and 1:400 (chi-squared test: p < 0.0001) for both pathogens and in humans only for E. cuniculi at the titre of 1:400 (chi-squared test: p < 0.0075).     

东方田鼠组织与血清中抗日本血吸虫相关蛋白的分离与筛选

本试验以兔、牛、人及感染日本血吸虫后小鼠血清蛋白为对照,分别提取东方田鼠和小鼠的心脏、肝脏、脾脏、肺脏、肾脏、肌肉、皮肤、骨髓和脑组织蛋白,进行聚丙烯酰胺凝胶电泳,综合比较和筛选东方田鼠组织及血清中潜在的抗日本血吸虫相关蛋白组分。结果表明,随着感染日龄的增加,小鼠在感染日本血吸虫后12和45 d,其血清中85 ku附近蛋白质条带较东方田鼠表达量明显上调,且有继续升高的趋势;东方田鼠肝脏及血清中150 ku组分蛋白电泳条带与其他动物相同组织中相应蛋白质在表达量存在显著差异,蛋白质表达丰度高,该蛋白质组分可能与东方田鼠抗日本血吸虫作用相关。     

Molecular typing of Salmonella enterica serovar 4,[5],12:i:- isolates from humans,animals and river water in Japan by multilocus variable-number tandem repeat analysis and pulsed-field gel electrophoresis

Fifty-one Salmonella enterica serovar 4,[5],12:i:- (S. 4, [5],12:i:-) isolates (14 human strains, 34 animal strains and 3 river water strains) which are assumed to be monophasic variants of S. Typhimurium were analyzed using pulsed-field gel electrophoresis (PFGE) and multiple-locus variable-number tandem repeat analysis (MLVA) in order to investigate their genetic diversities and relationships. PFGE, MLVA and combination of them identified 28, 27 and 34 profiles (Simpson’s diversity indices [DI]=0.94, 0.96 and 0.97), respectively. No correlations were detected between MLVA clustering and PFGE clustering or phage typing. These results suggested that S. 4,[5],12:i:- originated from multiple S. Typhimurium ancestors. Two cattle and one pig isolates showing identical phage types as well as PFGE and MLVA profiles to human isolates S. 4,[5],12:i:- suggested the existence of the links between human infections and animal reservoirs.     

PCR based differentiation between Streptococcus dysgalactiae subsp. equisimilis strains isolated from humans and horses

Streptococcus dysgalactiae subsp. equisimilis (SDSE) can be severely pathogenic in humans and is increasingly isolated from horses with respiratory, reproductive or other diseases, although it is often considered a commensal bacterium. Here a PCR protocol is described for identifying SDSE recovered from humans. A multiplex PCR targeting the 16S rRNA and the streptokinase precursor gene has been optimized for differentiating between SDSE strains isolated from humans and those isolated from horses. Previously, the sequence of the streptokinase precursor gene of SDSE recovered from horses has been found in two human cases of pneumonia in Japan.     

Characterisation of Escherichia fergusonii isolates from farm animals using an Escherichia coli virulence gene array and tissue culture adherence assays

Escherichia fergusonii has been associated with a wide variety of intestinal and extra-intestinal infections in both humans and animals but, despite strong circumstantial evidence, the degree to which the organism is responsible for the pathologies identified remains uncertain. Thirty isolates of E. fergusonii collected between 2003 and 2004 were screened using an Escherichia coli virulence gene array to test for the presence of homologous virulence genes in E. fergusonii. The iss (increased serum survival) gene was present in 13/30 (43%) of the test strains and the prfB (P-related fimbriae regulatory) and ireA (siderophore receptor IreA) genes were also detected jointly in 3/30 (10%) strains. No known virulence genes were detected in 14/30 (47%) of strains. Following confirmatory PCR and sequence analysis, the E. fergusoniiprfB, iss and ireA genes shared a high degree of sequence similarity to their counterparts in E. coli, and a particular resemblance was noted with the E. coli strain APEC O1 pathogenicity island. In tissue culture adherence assays, nine E. fergusonii isolates associated with HEp-2 cells with a ‘localised adherence’ or ‘diffuse adherence’ phenotype, and they proved to be moderately invasive. The E. fergusonii isolates in this study possess both some phenotypic and genotypic features linked to known pathotypes of E. coli, and support existing evidence that strains of E. fergusonii may act as an opportunistic pathogens, although their specific virulence factors may need to be explored.     

Perspectives on canine and feline hepatozoonosis

Two species of Hepatozoon are currently known to infect dogs and cause distinct diseases. Hepatozoon canis prevalent in Africa, Asia, southern Europe, South America and recently shown to be present also in the USA causes infection mainly of hemolymphoid organs, whereas Hepatozoon americanum prevalent in the southeastern USA causes myositis and severe lameness. H. americanum is transmitted by ingestion of the Gulf Coast tick Amblyomma maculatum and also by predation on infected prey. H. canis is transmitted by Rhipicephalus sanguineus, in South America also by Amblyomma ovale, and has also been shown to be transmitted transplacentally. Hepatozoonosis of domestic cats has been described mostly from the same areas where canine infection is present and the exact identity of the species which infect cats, their pathogenicity and vectors have not been elucidated. The diagnosis of hepatozoonosis is made by observation of gamonts in blood smears, histopathology, PCR or serology. The main treatment for H. canis is with imidocarb dipropionate whereas H. americanum infection is treated with an initial combination of trimethoprim-sulfadiazine, pyrimethamine and clindamycin followed by maintenance with decoquinate. Treatment for both diseases has not been reported to facilitate complete parasite elimination and new effective drugs are needed for the management of these infections. Prevention of hepatozoonosis should be based on avoidance of oral ingestion of infected tick vectors and infected prey.     

An epidemiological evaluation of Mycobacterium bovis infections in wild game animals of the Spanish Mediterranean ecosystem

Recreational hunting of indigenous wild artiodactyls has been one of the most lucrative and rapidly growing industries in Western Spain over the last five years. In the absence of careful ecological management, one consequence of the commercial exploitation of this natural resource has been the appearance of outbreaks of infectious disease; most notably bovine tuberculosis. From the outset of the study in 1997, we have observed a steady increase in prevalence of Mycobacterium bovis (M. bovis) in both species reaching 1.74 (+/-0.17) in deer in 2002 and 2.32 (+/-0.24) in wild boar. The latter species seems to be most severely affected with pulmonary lesions appearing more chronic than those observed in deer. In this study, we describe the epidemiology of M. bovis in European wild boar (Sus scrofa) and Iberian red deer (Cervus elaphus hispanicus) in Extremadura (W. Spain); a region where there are large areas of natural habitat for these species.