Dog vaccination with EgM proteins against Echinococcus granulosus.

BACKGROUND: Dogs play a pivotal role in the transmission of cystic echinococcosis (CE), a zoonosis caused by the tapeworm Echinococcus granulosus. We showed previously that dogs vaccinated with two E. granulosus adult-worm specific proteins, EgM9 and EgM123, emulsified with Freund's adjuvants induced significant protective efficacy in terms of reduction in worm burden and egg production after 45 days post-infection. It was not known whether this protection can be sustained using adjuvants suitable for use in dogs. METHODS: Recombinant EgM9 and EgM123 were mixed with Quil A or ISCOMs for vaccinating dogs. After three vaccine injections, all the dogs were orally challenge-infected with 200 000 protoscoleces of E. granulosus. After 45 days of infection, all the dogs were euthanized and necropsied for collecting and counting E. granulosus worms. Immunoglobins, including the IgG subclasses IgG1 and IgG2, were detected in the sera of vaccinated dogs by ELISA. To determine whether the protection efficacy could be maintained after 45 days post-infection, we implemented a longevity trial to count eggs in dog faeces for 170 days after infection. RESULTS: The dogs vaccinated with EgM9 and EgM123 mixed with Quil A and ISCOMs showed similar protective efficacy as the proteins emulsified with Freund's adjuvants in our previous study in terms of reduction of worms and eggs at 45 days post-infection. The longevity trial showed that EgM9 protein-vaccinated group released lower number of eggs per gram compared with the egg counts in the control dogs during the dog trial study. CONCLUSION: EgM9 and EgM123 are thus suitable vaccine candidates against E. granulosus infection in dogs.

Sequencing of complete mitochondrial genomes confirms synonymization of Hyalomma asiaticum asiaticum and kozlovi, and advances phylogenetic hypotheses for the Ixodidae.

Phylogeny of hard ticks (Ixodidae) remains unresolved. Mitochondrial genomes (mitogenomes) are increasingly used to resolve phylogenetic controversies, but remain unavailable for the entire large Hyalomma genus. Hyalomma asiaticum is a parasitic tick distributed throughout the Asia. As a result of great morphological variability, two subspecies have been recognised historically; until a morphological data-based synonymization was proposed. However, this hypothesis was never tested using molecular data. Therefore, objectives of this study were to: 1. sequence the first Hyalomma mitogenome; 2. scrutinise the proposed synonymization using molecular data, i.e. complete mitogenomes of both subspecies: H. a. asiaticum and kozlovi; 3. conduct phylogenomic and comparative analyses of all available Ixodidae mitogenomes. Results corroborate the proposed synonymization: the two mitogenomes are almost identical (99.6%). Genomic features of both mitogenomes are standard for Metastriata; which includes the presence of two control regions and all three "Tick-Box" motifs. Gene order and strand distribution are perfectly conserved for the entire Metastriata group. Suspecting compositional biases, we conducted phylogenetic analyses (29 almost complete mitogenomes) using homogeneous and heterogeneous (CAT) models of substitution. The results were congruent, apart from the deep-level topology of prostriate ticks (Ixodes): the homogeneous model produced a monophyletic Ixodes, but the CAT model produced a paraphyletic Ixodes (and thereby Prostriata), divided into Australasian and non-Australasian clades. This topology implies that all metastriate ticks have evolved from the ancestor of the non-Australian branch of prostriate ticks. Metastriata was divided into three clades: 1. Amblyomminae and Rhipicephalinae (Rhipicephalus, Hyalomma, Dermacentor); 2. Haemaphysalinae and Bothriocrotoninae, plus Amblyomma sphenodonti; 3. Amblyomma elaphense, basal to all Metastriata. We conclude that mitogenomes have the potential to resolve the long-standing debate about the evolutionary history of ticks, but heterogeneous evolutionary models should be used to alleviate the effects of compositional heterogeneity on deep-level relationships.

[Sexual reproductive allocation of Sargassum thunbergii at Taiping Cape of Yellow Sea].

This paper studied the dynamics of reproductive allocation (RA) of Sargassum thunbergii during its sexual reproductive season and the related environmental factors at the Taiping Cape of Yellow Sea. The sexual reproduction of S. thunbergii initiated in early June, peaked in mid July when the sea water temperature was about 22 degrees C (the mean proportion of biomass allocated to reproductive organs on July 19 was 76.7%), and ended in late August. The RA had a significant linear correlation with the average length of thallus branches (r = 0.855, P < 0.01). The thalli with a length less than 10 cm showed a lower RA in the whole sexual reproductive season, while the thalli longer than 10 cm had a RA up to averagely 70.0% at the peak maturing stage. UNIANOVA analysis showed that both tidal level and wave strength had significant effects on the RA of S. thunbergii (tidal level: F = 175.62, P < 0.01; wave strength: F = 95.35, P < 0.01), and there was a significant interaction between tidal level and wave strength (F = 9.14, P < 0.05). The sizes of the effects were in the order of tidal level > wave strength > tidal level x wave strength.

[Immune protection of recombinant membrane protein against Taenia multiceps larvae in sheep].

OBJECTIVE: To investigate the immune protection of the recombinant membrane protein(45M) against larvae of Taenia multiceps in sheep. METHODS: Twelve sheep were randomly divided into immune group and control group, and each sheep was immunized four times (three weeks interval) respectively with 50 microg recombinant 45M or GST emulsified with adjuvant. Serum samples were collected at pre-immunization and certain time after immunization, and were analyzed for IgG and IgM by ELISA. At the 105th day after the final inoculation, each sheep was orally challenged by 5000 eggs of T. multiceps. Two weeks after infection, the sheep were sacrificed, serum samples were collected, and number of cysts in brain tissue was counted. Activated oncospheres were cultured with 10% sera of immune group or control group, and observed by light microscopy. RESULTS: The mean number of cysts was 1.5, and the average diameter of the cysts was 2.2 mm. Compared with control group, the reduction rate of cysts in immunized sheep was 68.9%. At the 72th hour after culture with serum of immunized sheep, about 90% oncospheres were killed by antiserum, and the oncospheres began to shrink or expand, and internal structure became fuzzy. ELISA showed that after final immunization (the 9th week), the levels of IgG in sera of immune group (2.32+/-0.76) were significantly higher than those of the control (0.70+/-0.42) (t=4.47, P<0.01). At the 24th week the levels of IgG and IgM in sera of immune group (1.53+/- 0.81, 0.90+/-0.26) were significantly higher than those of the control (0.64+/-0.43, 0.43+/-0.15) (P<0.01). CONCLUSION: The recombinant 45M can induce certain humoral immune response.

[Monthly deworming in dogs for echinococcosis control in two counties of Xinjiang Uygur Autonomous Region].

OBJECTIVE: To verify the application and effectiveness of monthly deworming for all dogs in the control of Echinococcus granulosus infection. METHODS: Baited praziquantel was used to treat all registered dogs monthly by hydatid disease control officers at village level and all stray (unowned) dogs were eliminated in the counties of Hutubi and Wensu in 1987-1990 and 1990-1994 respectively. Prevalence of echinococcosis in dogs and sheep was recorded yearly. RESULTS: The infection rate in dogs decreased from 18.5% and 14.7% before implementation of the control measure to zero in 3-4 years in Hutubi and Wensu Counties respectively. Prevalence of hydatid disease in new born sheep was reduced by more than 85% in comparison to the same age sheep before the control program in both counties. CONCLUSION: "Monthly drug administration to all dogs" is an effective way to the control of echinococcosis in dogs and of hydatid disease in sheep.

[Immunolocalization of the antioxidant protein TPx of Echinococcus granulosus].

AIM: To study the localization of the antioxidant protein thioredoxin peroxidase (TPx) of Echinococcus granulosus (EgTPx) in the protoscoleces (PSC) of parasite. METHODS: The protoscoleces of E.granulosus were aspirated and pooled from sheep liver hydatid cysts. After digested by pepsin, the sedimented protoscoleces were used for paraffin sections. The localization of the antioxidant protein TPx of EgTPx was determined by using(polyclonal antibody against rEgTPx) and indirect immunofluorescence staining. RESULTS: Indirect immunofluorescence staining analysis indicated that the rEgTPx was mainly distributed in tegument, subtegument and calcareous corpuscle cells of the protoscolex. CONCLUSION: The wide distribution and large sites of EgTPx in the parasite hare been clearly determined, which will help further investigation into the biological functions and application of TPx protein.

[Exploration for building PACS and RIS].

This article elaborates key points of the PACS and RIS project: its overall planning, implementation step by step, integration of PACS and HIS based on IHE, and the prudent selection of partners and so on.