Genetic characterization of Toxoplasma gondii isolates from eared doves (Zenaida auriculata) in Brazil

Eared doves (Zenaida auriculata), which are common in urban, rural and wild areas in many regions of Brazil, are frequently prey for domestic cats. Therefore Toxoplasma gondii isolates obtained from doves may reflect greater environmental diversity than those from other hosts. The aim of the present study was to evaluate T. gondii seroprevalence, isolate and genotype strains from Z. auriculata. Serum and tissue samples were collected from 206 doves for use in the modified agglutination test (MAT) and mouse bioassay. The prevalence of T. gondii antibodies in the doves was 22.3% (46/206), with titers ranging from 16 to 4096, and T. gondii strains were isolated from 12 of these doves. Five genotypes were detected by means of PCR-RFLP, including ToxoDB genotypes #1, #6, #17 and #65, and one genotype that had not previously been described (ToxoDB#182). This was the first report on isolation of T. gondii from Z. auriculata. This study confirmed the genetic diversity of T. gondii isolates and the existence of clonal type II (ToxoDB genotype #1) in Brazil.

Immune response of calves inoculated with proteins of Anaplasma marginale bound to an immunostimulant complex

Despite our current knowledge of the immunology, pathology, and genetics of Anaplasma marginale, prevention in cattle is currently based on old standbys, including live attenuated vaccines, antibiotic treatment, and maintaining enzootic stability in cattle herds. In the present study, we evaluated the use of an immunostimulant complex (ISCOMATRIX) adjuvant, associated with a pool of recombinant major surface proteins (rMSP1a, rMSP1b, rMSP4 and rMSP5) to improve the humoral immune response triggered in calves mainly by IgG2. Ten calves were divided in three groups: 4 calves were inoculated with the ISCOMATRIX/rMSPs (G1); 2 calves were inoculated with ISCOMATRIX adjuvant (G2); and 4 calves received saline (G3). Three inoculations were administered at 21-day intervals. In G1, the calves showed significant increases in total IgG, IgG1 and IgG2 levels 21 days after the second inoculation, compared to the control group (p < 0.05), and G1 calves remained above the cut-off value 28 days after the third inoculation (p < 0.05). The post-immunized sera from calves in G1 reacted specifically for each of the rMSPs used. In conclusion, the ISCOMATRIX/rMSPs induced antigen-specific seroconversion in calves. Therefore, additional testing to explore the protection induced by rMSPs, both alone and in conjunction with proteins previously identified as subdominant epitopes, is warranted.

Serological survey of Ehrlichia species in dogs, horses and humans: zoonotic scenery in a rural settlement from southern Brazil

The aims of this study were to determine the seroprevalence of Ehrlichia spp. and risk factors for exposure in a restricted population of dogs, horses, and humans highly exposed to tick bites in a Brazilian rural settlement using a commercial ELISA rapid test and two indirect immunofluorescent assays (IFA) with E. canis and E. chaffeensis crude antigens. Serum samples from 132 dogs, 16 horses and 100 humans were used. Fifty-six out of 132 (42.4%) dogs were seropositive for E. canis. Dogs > one year were more likely to be seropositive for E. canis than dogs ≤ one year (p = 0.0051). Ten/16 (62.5%) and 8/16 (50%) horses were seropositive by the commercial ELISA and IFA, respectively. Five out of 100 (5%) humans were seropositive for E. canis and E. chaffeensis. Rhipicephalus sanguineus (n = 291, 97.98%) on dogs and Amblyomma cajennense (n = 25, 96.15%) on horses were the most common ticks found. In conclusion, anti-Ehrlichia spp. antibodies were found in horses; however, the lack of a molecular characterization precludes any conclusion regarding the agent involved. Additionally, the higher seroprevalence of E. canis in dogs and the evidence of anti-Ehrlichia spp. antibodies in humans suggest that human cases of ehrlichiosis in Brazil might be caused by E. canis, or other closely related species.

First record of Borrelia burgdorferi B31 strain in Dermacentor nitens ticks in the northern region of Parana (Brazil)

The aim of this study was to investigate the presence of DNA of Borrelia burgdorferi sensu lato (s.l.) in ticks that feed on horses used for animal traction in rural Jataizinho, Parana, Brazil. Between February and June 2008, a total of 224 ticks was collected of which 75% were identified as Dermacentor nitens and 25% as Amblyomma cajenense. To amplify B. burgdorferi s.l. DNA, the intergenic space region (ISR) between the 5S (rrf) 23S (rrl) rRNA genes was used as targets for nested-PCR. Two ticks of the D. nitens species were positive for B. burgdorferi s.l. Both species showed a fragment of 184 bp, but the sequencing revealed 99.9% homology with the B. burgdorferi sensu stricto (s.s.) strain B31. These results showed, for the first time, the presence of spirochete DNA infecting ticks that parasitize horses used for animal traction, in the rural municipality mentioned. In conclusion, this study opens up promising prospects for determining the infection rate of B. burgdorferi s.s. genospecies or other species in the equine population, as well as the impact of the infection rate on Lyme disease in the state of Parana.

Molecular detection and occurrence of 'Candidatus Mycoplasma haemobos' in dairy cattle of Southern Brazil

Bovine hemoplasmas are bacteria found on the erythrocyte surface or free in the plasma of cattle. The aim of the present study was to evaluate the occurrence of 'Candidatus Mycoplasma haemobos' ('C. M. haemobos') in Holstein and Jersey cattle raised in Londrina and surroundings, northern region of the State of Parana, Southern Brazil. PCR testing directed to 16S rRNA gene fragment was performed to investigate the occurrence and characterize the molecular identity of 'C. M. haemobos'. A total of 264/433 (60.97%) blood samples were positive by PCR. Further alignment of 500-bp amplicons to available sequences at the GenBank database showed high identity (100%) to 'C. M. haemobos'. To the author's knowledge, this is the first molecular confirmation of the hemoplasma 'C. M. haemobos' in cattle from Brazil. Moreover, 'C. M. haemobos' was observed in high occurrence in dairy cattle, and may have significant impact in livestock production.

Seroepidemiological survey of Theileria equi and Babesia caballi in horses from a rural and from urban areas of Paraná State, southern Brazil

The objective of this study was to evaluate the seroepidemiological data of Babesia caballi and Theileria equi in horses from a rural settlement and carthorses from urban areas of Paraná State, southern Brazil. A total of 198 horses, including 32 from the rural settlement and 166 carthorses from Colombo (n=48), Pinhais (n=76), Londrina (n=24), and Curitiba city (n=18) was sampled and tested using a commercial competitive inhibition ELISA (cELISA) test. Out of the 198 horses, 193 (97.5%) were seropositive for at least one piroplasm species. Antibodies to T. equi were detected in 155/198 horses (78.3%), antibodies to B. caballi were detected in 137/198 horses (69.2%), and antibodies to both were detected in 99/198 (50.0%) horses. Horses living in the rural settlement and Colombo were more likely to be seropositive to T. equi than those in Curitiba (p<0.05). Horses older than 5 years were more likely to be seropositive for T. equi than those younger than 5 years (p<0.05). No significant association was found between gender or the presence of ticks and seropositivity to T. equi (p>0.05). In conclusion, the high seroprevalences to B. caballi and T. equi observed in this study emphasize that active surveillance programs are critical for monitoring animal health status, particularly because carthorses may act as urban disseminators of these piroplasms.

Occurrence of gastrointestinal and renal helminths inZenaida auriculata (Des Murs, 1847) trap-captured from Brazil

This study aimed to determine the prevalence of gastrointestinal and renal helminths from naturally infected Zenaida auriculatacaptured in Londrina, Paraná State. Two hundred and one Eared doves were trapped and the gastrointestinal and renal helminths were collected and identified according to morphological structures. One hundred and sixteen (57.71%) doves were parasitized by helminths with specific prevalences forOrnithostrongylus quadriradiatus in 50 doves (24.88%),Ascaridia columbae in 47 (23.38%), Paratanaisia bragai and P. confusa in 34 (16.92%),Tetrameres fissispina in 17 (8.46%), Synhimantus nasuta in 14 (6.47%), Brachylaima mazzantii in 4 (1.99%) and Raillietina allomyodes in 2 doves (1.00%). Seventy four/201 (37.00%) birds were infected with only one species, and 96/201 (48.00%) pigeons were infected with nematodes. The association between different classes of helminths occurred in 40/201 (20.00%) animals. The results showed statistically differences between the presence of nematode (p = 0.00001) and trematode species (p ≤ 0.05) in the doves, and there was an association between the local of capture and the presence of trematodes and A. columbae (p ≤ 0.05). This study is the first to report the infection of Z. auriculata from Brazil with O. quadriradiatus, A. columbae, T. fissispina, S. nasuta, R. allomyodes, P. bragai and P. confusa.

Occurrence of Ehrlichia canis and Anaplasma platys in household dogs from northern Parana

Canine monocytic ehrlichiosis caused primarily by Ehrlichia canis and canine thrombocytic anaplasmosis induced by Anaplasma platys are important emerging zoonotic tick-borne diseases of dogs. There is evidence that these pathogens can also affect humans. This study evaluated the presence of E. canis and A. platys in blood samples collected from 256 domiciled dogs in the municipality of Jataizinho, located in north region of the State of Parana, Brazil, by PCR assay. The occurrence of E. canis and A. platys was 16.4% (42/256) and 19.4% (49/256), respectively; while 5.47% (14/256) of the dogs evaluated were co-infected by these two organisms. The presence of E. canis and A. platys was not significantly associated with the variables evaluated (sex, age, outdoor access, and presence of ticks during blood collection). Infection of dogs by E. canis was associated with anemia and thrombocytopenia, while infection induced by A. platys was related only to thrombocytopenia. Canine monocytic ehrlichiosis and canine thrombocytic anaplasmosis should be included in the differential diagnoses when these hematological alterations are observed during routine laboratory evaluation of dogs.

Ehrlichiosis in Brazil

Ehrlichiosis is a disease caused by rickettsial organisms belonging to the genus Ehrlichia. In Brazil, molecular and serological studies have evaluated the occurrence of Ehrlichia species in dogs, cats, wild animals and humans. Ehrlichia canis is the main species found in dogs in Brazil, although E. ewingii infection has been recently suspected in five dogs. Ehrlichia chaffeensis DNA has been detected and characterized in mash deer, whereas E. muris and E. ruminantium have not yet been identified in Brazil. Canine monocytic ehrlichiosis caused by E. canis appears to be highly endemic in several regions of Brazil, however prevalence data are not available for several regions. Ehrlichia canis DNA also has been detected and molecularly characterized in three domestic cats, and antibodies against E. canis were detected in free-ranging Neotropical felids. There is serological evidence suggesting the occurrence of human ehrlichiosis in Brazil but its etiologic agent has not yet been established. Improved molecular diagnostic resources for laboratory testing will allow better identification and characterization of ehrlichial organisms associated with human ehrlichiosis in Brazil.

Toxoplasma gondii: humoral and cellular immune response of BALB/c mice immunized via intranasal route with rTgROP2

TgROP2 is an intracellular protein associated with rhoptries of Toxoplama gondii and an antigen component of a candidate vaccine for toxoplasmosis. The purpose of the present study was to evaluate the efficacy of rTgROP2 to stimulate humoral and cellular immune responses in BALB/c mice via intranasal injection. TgROP2 partial coding sequence was (196-561) amplified by PCR from genomic T. gondii RH strain DNA and cloned into the pTrcHis expression vector. Escherichia coli Rosetta 2 cells transformed with pTrcHis-TgROP2 showed high levels (~1 mg.mL(-1)) of recombinant protein after 4 hours of IPTG induction. Recombinant TgROP2 exhibited an apparent Mr equal to 54 kDa. In order to test immunogenicity of the recombinant protein, 10 BALB/c mice received 10 µg of rROP2 protein + 10 µg of Quil-A via intranasal injection. Doses were administered at days 0, 21, and 42. Three animals were euthanized and used to evaluate cellular immune response on day 62. Five (50%) and two (20%) out of ten animals produced IgG (DO mean = 0.307; cut-off = 0.240) and IgA (DO mean = 0.133, cut-off = 0.101), respectively, by ELISA on day 62. The proliferation of splenocytes revealed high stimulation index (SI) when co-cultured with 5, 10 and 15 µg.mL(-1) of rTgROP2. These results indicate that intranasal immunization with recombinant protein ROP2 plus Quil-A can elicit both cellular and humoral immune responses in BALB/c mice.

Serosurvey of antibodies against spotted fever group Rickettsia spp. in horse farms in Northern Paraná, Brazil

Brazilian spotted fever (BSF) is an emerging disease most likely caused by Rickettsia rickettsii. The objective of the present study was to estimate the seroprevalence of BSF rickettsia infections in equines from six horse farms located in Londrina County, Paraná, Southern Brazil. Six owners of horse farms situated in Cambé, Santa Fé, Guaraci and Londrina municipalities participated in the study. All farms were located in areas where BSF has not been reported. A total of 273 horses were sampled and their sera were tested by indirect immunofluorescence assay (IFA) using R. rickettsii and R. parkeri antigens. Titers equal to and greater than 64 were considered positive. Of 273 sera tested, 15 (5.5%) reacted to R. rickettsii and 5 (1.8%) to R. parkeri. Five out of the six farms studied revealed seropositive animals and seropositivity rate ranged from 0 to 13%. The titers ranged from 64 to 512, and four samples had a titer of 512. Nine animals reacted to R. rickettsii with titers four-fold higher than those for R. parkeri. These results suggest that horses in Northern Paraná may have been exposed to rickettsiae identical or closely related to R. rickettsii.

Study of infection by Rickettsiae of the spotted fever group in humans and ticks in an urban park located in the City of Londrina, State of Paraná, Brazil

INTRODUCTION: Spotted fevers are emerging zoonoses caused by Rickettsia species in the spotted fever group (SFG). Rickettsia rickettsii is the main etiologic agent of Brazilian spotted fever (BSF) and it is transmitted by Amblyomma spp. ticks. METHODS: The study aimed to investigate SFG rickettsiae in the Arthur Thomas Municipal Park in Londrina, PR, by collecting free-living ticks and ticks from capybaras and blood samples from personnel working in these areas. Samples from A. dubitatum and A. cajennense were submitted for PCR in pools to analyze the Rickettsia spp. gltA (citrate synthase gene). RESULTS: All the pools analyzed were negative. Human sera were tested by indirect immunofluorescence assay with R. rickettsii and R. parkeri as antigens. Among the 34 sera analyzed, seven (20.6%) were reactive for R. rickettsii: four of these had endpoint titers equal to 64, 2 titers were 128 and 1 titer was 256. None of the samples were reactive for R. parkeri. An epidemiological questionnaire was applied to the park staff, but no statistically significant associations were identified. CONCLUSIONS: The serological studies suggest the presence of Rickettsiae related to SFG that could be infecting the human population studied; however, analysis of the ticks collected was unable to determine which species may be involved in transmission to humans.

Use of a Mycoplasma suis-PCR protocol for screening a population of captive peccaries (Tayassu tajacu and Tayassu pecari)

Mycoplasma suis is a hemotropic bacteria of red blood cells and the causative agent of swine eperythrozoonosis. Diagnosis of infection may be reached by direct examination of blood smears; however, the use of polymerase chain reaction (PCR) of the 16S RNA gene of M. suis improves the sensitivity and specificity of detection. The aim of this study was to screen peccaries (Tayassu tajacu and T. pecari) for M. suis infection using a specific conventional PCR. A total of 28 blood samples from captive collared and white-lipped peccaries were collected, DNA extracted and a specific M. suis PCR assay performed. All samples were negatives by both blood smear examination and PCR testing. To verify the presence of amplifiable DNA, PCR for beta-actin gene was performed in all samples. This study was part of an active surveillance program, which is crucial for monitoring animal health status, particularly in wildlife species.

Infection by spotted fever rickettsiae in people, dogs, horses and ticks in Londrina, Parana State, Brazil

Spotted fever is a disease caused by bacteria from the genus Rickettsia of the spotted fever group (SFG). Rickettsia rickettsii is likely the main agent of Brazilian spotted fever (BSF). With the objective of gathering information on the circulation of SFG rickettsiae in Londrina, Parana state, ticks from dogs and horses and also blood from dogs, horses and humans were collected in a neighbourhood of the city which presented potential for circulation of rickettsiae between hosts and vectors. Amblyomma cajennense, Dermacentor nitens, and Rhipicephalus sanguineus ticks were subjected to Polymerase Chain Reaction targeting a fragment of the Rickettsia gltA gene. This specific gene encodes the enzyme citrate synthase of Rickettsia spp., and results on all ticks were negative. Human and animal sera were tested by Indirect Immunofluorescence Assay in which R. rickettsii and R. parkeri were used as antigens. Sera from 4.7% human, 2.7% canine and 38.5% equine were positive for R. rickettsii. For R. parkeri, 0.9% human, 2.7% canine and 11.5% equine samples were positive. All samples reactive to R. parkeri also reacted to R. rickettsii. An epidemiological questionnaire was applied, but there were no statistically significant results. Comparison of our serological results with previous studies in Brazil, among BSF endemic and non-endemic areas, indicates that there is no established rickettsial infection in the study area, a statement corroborated with our molecular analysis. Nonetheless, as humans of the present study are highly exposed to tick infestations, health education within the population is needed to obtain efficient tick control.

Neorickettsia helminthoeca and salmon poisoning disease: a review

Neorickettsia helminthoeca is an obligate intra-cytoplasmic bacterium that causes salmon poisoning disease (SPD), an acute, febrile, fatal disease of dogs. The complex life-cycle of this pathogen involves stages in an intestinal fluke (Nanophyetus salmincola), a river snail (Oxytrema silicula), in fish, and in fish-eating mammals. This complexity has created confusion with respect to the various bacterial and parasitic infections associated with the disease and its significance in dogs in specific geographical locations has likely to have previously been under-estimated. This paper addresses the history, taxonomy, microbiology of N. helminthoeca and summarises the pathogenesis, clinical signs and pathological features associated with infection. Furthermore, the biological cycles, treatment, control, and both public and veterinary health impacts associated with this pathogen and the intestinal fluke N. salmincola are discussed.

[Cloning, expression, molecular characterization of the MSP5 protein from PR1 strain of Anaplasma marginale and its application in a competitive enzyme-linked immunosorbent test]

A competitive enzyme-linked immunosorbent test using the PR1 recombinant major surface protein 5 (rMSP5-PR1-ELISA) of Anaplasma marginale was standardized and validated using sera from anaplasmosis free and endemic regions. The sequencing of the msp5 gene of PR1 isolate showed 98% of identity with the Florida and Saint Maries isolates, 97% with Brazil (Pernambuco) and Havana isolates; and 91% with A. centrale. The cELISA-PR1 test was compared to IFI and cELISA-USA. For the standardization and validation of the cELISA-PR1, 380 bovine sera were used, whereas 245 truly positives and 135 truly negatives sera tested by the cELISA-USA. In the standardization of the cELISA-PR1 135 negative and 148 positive bovine sera were used. The cELISA-PR1 and IFI tests showed 100 and 99.3% specificity, 100 and 98%, sensibility, and a kappa coefficient of 0.993 and 0.978, respectively. For test validation, 245 bovine sera from an anaplasmosis endemic area were analyzed by the cELISA-PR1 and IFI, which showed 96.7 and 69.1% specificity, 98.9 e 96.3% sensibility and kappa coefficient of 0.956 and 0.699, respectively. These results indicate that the cELISA-PR1, likewise the cELISA-USA, could sensitively and specifically detect cattle naturally infected with A. marginale and would be recommended for epidemiological studies, eradications program, and regulation of international cattle movement, while IFI, which presented lower specificity should not be used in situations that demand more specific diagnosis.

Cloning, sequencing and antigenic characterization of rVirB9 of Anaplasma marginale isolated from Paraná State, Brazil

Anaplasma marginale, a tick-borne bacterium, causes bovine anaplasmosis responsible for significant economic losses in tropical and subtropical regions worldwide. Various major outer membranes have been described, and VirB9, a type IV secretion system protein, has been recently indicated as a candidate in vaccine development against anaplasmosis. The virB9 gene of an A. marginale strain isolated in Paraná, Brazil, was cloned by polymerase chain reaction and sequenced; its cloning into the pETSUMO vector produced a virB9-SUMO-6x His fusion gene construct. This recombinant clone was over-expressed in Escherichia coli BL21 (DE3), and the expressed fusion protein was solubilized with urea and purified with an Ni-NTA column. This method produced a relatively high yield of rVirB9. The deduced amino acid sequence encoded by VirB9 showed 99% homology to A. marginale isolates from St. Maries. rVirB9 was recognized by serum from cattle immunized with PR1 strain and by bovine sera infected with heterologous strains, showing that rVirB9 has conserved epitopes, which suggests that rVirB9 could be useful for the development of a vaccine against anaplasmosis.

[Occurrence and molecular characterization of Babesia species in a canine hospital population in the Londrina Region, Parana State, Brazil]

Canine babesiosis is a worldwide disease caused by the protozoan of Babesia genus. Babesia canis and B. gibsoni are both species that naturally infect dogs. The objective of this study was to evaluate the infection of Babesia species in dogs attended at the Londrina State University Veterinary Teaching Hospital (HV-UEL). It was selected 282 dogs seen at the Londrina State University Veterinary Teaching Hospital (HV-UEL) between April of 2005 and May of 2006. They presented anemia (Packed Cell Volume<25%), thrombocytopenia (Platelet count <150000/mm3), leukopenia (White blood cell count<5000/mm3) or a combination of two or three of these alterations at the moment of the consultation. The presence of Babesia sp was determined by the amplification of a specific fragment of DNA of the Babesia genus by PCR. Microscopic examination of Giemsa-stained blood smears detected 38 (13.5%) positive samples against 105 identified by PCR from 282 dogs. The positive samples were submitted to PCR-RFLP by Hinf I that allows distinguishing the species of B. canis vogeli and B. gibsoni. From 282 dogs, Babesia sp infection was identified in 105 (37.2%). From these 105 positive samples, the PCR-RFLP identified 66 (23.4%) samples with a profile compatible to B. canis vogeli and 39 (13, 8%) to B. gibsoni. As conclusions, the results obtained allow to affirm that the babesiose is an important differential for dogs that present anemia, leukopenia and thrombocytopenia and, B. canis vogeli is the subspecies that is present in the most of the cases of babesiose in the population of dogs studied and, that B. gibsoni is also present causing babesiosis in dogs of the Londrina region, Parana State, Brazil.