Acaricidal efficacy and chemical study of hexane extracts of the leaves of Neoglaziovia variegata (Bromeliaceae) against the tick Rhipicephalus microplus.

The frequent use of acaricides against the tick Rhipicephalus microplus increases the risk of development of resistance. Recent studies have revealed that Neoglaziovia variegata, an indigenous plant species known in Brazil as 'caroá', has a deleterious effect against R. microplus. In the current study, extracts of N. variegata were studied for their possible acaricidal properties. A hexane extract of N. variegata leaves was fractionated in a chromatography column and the fractions were tested in adult tick immersion tests in triplicate using three concentrations (5, 10 and 25 mg/ml). All the fractions had harmful effects on the ticks. However, three fractions were more efficaceous. Phytochemical analysis indicated that stigmast-5-en-3-ol and stigmastanol were most abundant; they might be responsible for the acaricidal effects, making them potentially useful as alternative agents to control the tick R. microplus.

Anthelmintic resistance of gastrointestinal nematodes in sheep grazing in irrigated and dry areas in the semiarid region of northeastern Brazil.

This study aimed to determine the AR of gastrointestinal nematodes (GIN) to commercial drugs in sheep flocks naturally infected, grazing in irrigated (IA) and dry (DA) areas of the semiarid region in northeastern Brazil. Fecal egg count reduction tests (FECRT) were performed at 10 farms. From each flock, 36 adult sheep were selected and divided into five groups (G1 (0.08% ivermectin), G2 (10% albendazole), G3 (5% levamisole), G4 (1% moxidectin), G5 (10% closantel) and one control group, G6). All the commercial drugs were found to reduce the number of eggs per gram of feces (EPG). Resistance to ivermectin (37.1%), albendazole (52.1%), and levamisole (52.0%) was detected at all the farms, but nematodes proved to be susceptible to moxidectin (87.9%) and closantel (83.9%). The overall average efficacy of the commercial drugs was significantly higher (P < 0.05) in DA (49.2%), where moxidectin (90.4%) showed high effectiveness. The presence of the parasite Haemonchus contortus predominated at all the farms. The variables irrigated area (P = 0.002), intensive breeding (P = 0.018), uncovered enclosures (P = 0.05), cultivated (P = 0.043) and native/cultivated (P = 0.007) pastures, and rotational grazing (P = 0.013) were significantly associated with GIN infection; irrigated area (P = 0.009), semi-intensive breeding (P = 0.05), rotational grazing (P = 0.045), cultivated (P = 0.021) and native/cultivated (P = 0.04) pastures, and estimated weighing of animals (P = 0.002) were significantly associated with AR. Therefore, improved management practices and strategic deworming must be implemented to prevent the development of AR.

Ectoparasites of small mammals in a fragmented area of the southern Amazonia: interaction networks and correlations with seasonality and host sex.

The present work aimed to analyze the ectoparasite-host interaction network and possible differences of this interaction related to two seasonal periods and host sex. During November 2016 and July 2017, non-flying small mammals were captured in 17 forest fragments located in the southern portion of the Amazon biome. We captured 96 individuals belonging to 10 host species that were parasitized with a total of 3668 ectoparasites. Overall, we identified 24 ectoparasite taxa belonging to the mite and insect groups Ixodida (ticks), Mesostigmata, Sarcoptiformes, Trombidiformes (mites), Phthiraptera (lice), and Siphonaptera (fleas). The interaction network between all ectoparasites and hosts showed significant deviation from random, with moderately high specialization index (H2' = 0.80). There was seasonal difference in prevalence for Amblyomma cajennense (Fabricius) sensu stricto (s.s), Amblyomma coelebs Neumann and larvae of Amblyomma. This difference was also found in the mean intensity of infestation of Amblyomma larvae and the mite Tur aragaoi (Fonseca). Only mean intensity of infestation differed in relation to host sex for the species Marmosa constantiae Thomas. Our results demonstrate that specificity between ectoparasites and small mammals in this region is moderately high and that the pattern of aggregation of some ectoparasite taxa differed between two seasons, as well as between sexes in M. constantiae.

A high gene flow in populations of Amblyomma ovale ticks found in distinct fragments of Brazilian Atlantic rainforest.

The genetic structure of populations of the tick Amblyomma ovale from five distinct areas of the Brazilian Atlantic rainforest was evaluated via DNA sequencing and associated with the presence of domestic dogs acting as hosts at the edge of forest fragments. Ticks were collected from domestic dogs and from the environment between 2015 and 2017. Four collection areas were located in the surroundings and within the Serra do Mar State Park, São Paulo State (23°37'21"S, 45°24'43"W), where dogs were bimonthly monitored along 2 years using camera traps and GSM trackers. To determine the spatial limits of genetic structure, ticks collected upon dogs living near the Serra do Baturié, Ceará State (4°15'40"S, 38°55'54"W) were included as well. A total of 39 haplotypes of 16S rRNA and Cox 1 mitochondrial genes sequences were observed, with 27 of them coming from areas within the Serra do Mar State Park. No haplotype was shared between the Serra do Mar and the Serra do Baturié indicating isolation of tick populations at the scale of 2000 km. Although three different haplotype lineages of A. ovale occurred within the Serra do Mar State Park, no genetic structure was found across the study sites within this park, suggesting high tick gene flow across a range of 45 km. Monitoring data from domestic dogs and wild carnivores showed that these species share the same habitats at the forest edge, with dogs playing a likely limited role in tick dispersal. Our findings have important implications for understanding the genetic structure of wide spread A. ovale along Brazilian rainforest remnants, which can further be associated to tick-borne infectious agents, such as Rickettsia parkeri, and used for predicting future patterns of tick diversity in the Brazilian Atlantic rainforest.

New records of soft ticks (Acari: Argasidae) from caves in Brazil, with a morphological study of Ornithodoros fonsecai and an analysis of the taxonomic status of Antricola inexpectata.

In this study, we report soft ticks from bat-inhabiting caves in different areas of Brazil. From 2010 to 2019, we collected 807 tick specimens from nine caves located in four Brazilian states among two biomes. Ticks were morphologically identified as Antricola guglielmonei (282 specimens), Ornithodoros cavernicolous (260 specimens), and Ornithodoros fonsecai (265 specimens). Whereas A. guglielmonei was collected on bat guano in hot caves, O. cavernicolous and O. fonsecai were collected in cracks and crevices on the walls of cold caves, sometimes in the same chamber. Morphological identifications were corroborated by molecular and phylogenetic analyses inferred from tick mitochondrial 16S rRNA gene partial sequences. The sequences of A. guglielmonei, O. cavernicolous and O. fonsecai collected in this study clustered with conspecific GenBank sequences from different localities of Brazil. Remarkably, a clade containing 12 sequences of O. fonsecai was clearly bifurcated, denoting a degree of genetic divergence (up to 5 %) of specimens from Cerrado/Atlantic Forest biomes with the specimens from the Caatinga biome. To further evaluate this divergence, we performed morphometric analysis of the larval stage of different O. fonsencai populations by principal component analysis, which indicated that the larvae from Caatinga populations were generally smaller than the larvae from other biomes. Some of the present A. guglielmonei specimens were collected from the type locality of Antricola inexpectata. Comparisons of these specimens with the type specimens of A. inexpectata and A. guglielmonei indicated that they could not be separated by their external morphology. Hence, we are relegating A. inexpectata to a synonym of A. guglielmonei. This proposal is corroborated by our phylogenetic analysis.

A Novel Relapsing Fever Group Borrelia Isolated from Ornithodoros Ticks of the Brazilian Caatinga.

Tick-borne relapsing fever group (RFG) borreliosis remains neglected as a human disease and little is known on its maintenance in ticks and vertebrates, especially in South America. Therefore, this study investigated borrelial infection in Ornithodoros ticks collected in rodent-inhabited rock formations in the Brazilian semiarid region, within the Caatinga biome. Collected ticks (Ornithodoros rietcorreai and Ornithodoros cf. tabajara) were allowed to feed under laboratory conditions on guinea pigs, which had blood samples examined daily by dark-field microscopy. No spirochetes were visualized in the blood of any of four O. rietcorreai-infested guinea pigs. Contrastingly, spirochetes were visualized between 9 and 39 days after tick feeding in the blood of three guinea pigs, each infested with O. cf. tabajara ticks from a different locality. Guinea pig infection was confirmed by passages into experimental animals and by generating DNA sequences of Borrelia spp. from the blood of spirochetemic guinea pigs. Three O. cf. tabajara populations were infected by the same borrelial organism, which was characterized as a novel RFG agent (named as 'Candidatus Borrelia caatinga') based on 10 Borrelia loci (rrs, flaB, glpQ, gyrB, clpX, pepX, pyrG, recG, rplB and uvrA). We demonstrated that O. cf. tabajara is a competent vector of the novel Borrelia sp. isolates, although none of the infected rodents developed clinical illness.

Rickettsia felis infection in cat fleas ctenocephalides felis felis.

The present study evaluated the rickettsial infection in a laboratory colony of cat fleas, Ctenocephalides felis felis (Bouche) in Brazil. All flea samples (30 eggs, 30 larvae, 30 cocoons, 30 males, and 30 females) tested by polymerase chain reaction (PCR) were shown to contain rickettsial DNA. PCR products, corresponding to the rickettsial gltA, htrA, ompA and ompB gene partial sequences were sequenced and showed to correspond to Rickettsia felis, indicating that the flea colony was 100% infected by R. felis. The immunofluorescence assay (IFA) showed the presence of R. felis-reactive antibodies in blood sera of 7 (87.5%) out of 8 cats that were regularly used to feed the flea colony. From 15 humans that used to work with the flea colony in the laboratory, 6 (40.0%) reacted positively to R. felis by IFA. Reactive feline and human sera showed low endpoint titers against R. felis, varying from 64 to 256. With the exception of one human serum, all R. felis-reactive sera were also reactive to Rickettsia rickettsii and/or Rickettsia parkeri antigens at similar titers to R. felis. The single human serum that was reactive solely to R. felis had an endpoint titer of 256, indicating that this person was infected by R. felis.

Rocky Mountain spotted fever in dogs, Brazil.

Clinical illness caused by Rickettsia rickettsii in dogs has been reported solely in the United States. We report 2 natural clinical cases of Rocky Mountain spotted fever in dogs in Brazil. Each case was confirmed by seroconversion and molecular analysis and resolved after doxycycline therapy.

Experimental infection of capybaras Hydrochoerus hydrochaeris by Rickettsia rickettsii and evaluation of the transmission of the infection to ticks Amblyomma cajennense.

The present study evaluated the infection of capybaras (Hydrochoerus hydrochaeris) by Rickettsia rickettsii and their role as amplifier hosts for horizontal transmission of R. rickettsii to Amblyomma cajennense ticks. Two groups of two capybaras each were evaluated: on day 0, group 1 (G1) was infested by R. rickettsii-infected ticks, and group 2 (G2) was inoculated intraperitoneally with R. rickettsii. Two additional groups were control groups, not exposed to R. rickettsii, being CG1 group the control of G1, and CG2 group the control of G2. Capybara rectal temperature was measured daily. Blood samples were collected every 3 days during 30 days, and used to (i) inoculate guinea pigs intraperitoneally; (ii) DNA extraction followed by real-time PCR targeting the rickettsial gene gltA; (iii) hematology; (iv) detection of R. rickettsii-reactive antibodies by indirect immunofluorescence assay (IFA). Blood was also collected from G1 capybaras every approximately 10-30 days till the 146th day, to be tested by serology. Capybaras were infested by uninfected A. cajennense nymphs from the 3rd to the 18th day. Engorged nymphs were collected, allowed to molt to adults in an incubator. Thereafter, the subsequent flat ticks were tested by PCR. All G1 and G2 capybaras became infected by R. rickettsii, as demonstrated by guinea pig inoculation and seroconversion, but they showed no fever. Rickettsemia was continually detected from the 6th (G2 capybaras) or 9th (G1 capybaras) to the 18th day post inoculation or infestation with R. rickettsii-infected ticks. A total of 20-25% and 30-35% of the flat ticks previously fed on G1 and G2 capybaras, respectively, became infected by R. rickettsii. The study demonstrated that R. rickettsii was capable to infect capybaras without causing clinical illness, inducing rickettsemia capable to cause infection in guinea pigs and ticks. Our results indicate that capybaras act as amplifier host of R. rickettsii for A. cajennense ticks in Brazil.

Prevalence of Rickettsia species antibodies and Rickettsia species DNA in the blood of cats with and without fever.

Rickettsia species antibodies have been detected in some cats but it is unknown whether infected cats develop clinical signs. The prevalence of Rickettsia species deoxyribonucleic acid (DNA) in blood from clinically ill cats has not been determined. The objective of this study was to determine if cats with fever (body temperature >or=102.5 degrees F [39.2 degrees C]) were more likely to have evidence of rickettsial infection than healthy, age-matched, control cats with a body temperature<102.5 degrees F. Rickettsia species polymerase chain reaction (PCR) assays were performed to detect rickettsial DNA extracted from blood (71 paired samples), indirect immunofluorescence assays (IFA) were performed to detect serum antibodies against Rickettsia felis (90 paired samples) and Rickettsia rickettsii (91 paired samples), and the results between pairs were compared. All samples were negative for Rickettsia species DNA. More cats with fever were seropositive for R felis or R rickettsii than control cats, but results were not statistically significant. Results of this pilot study failed to show an association between Rickettsia species DNA or Rickettsia species antibodies and fever.

Comparative susceptibility of larval stages of Amblyomma aureolatum, Amblyomma cajennense, and Rhipicephalus sanguineus to infection by Rickettsia rickettsii.

The current study compared the susceptibility of larval stages of Amblyomma cajennense (F.), Amblyomma aureolatum (Pallas), and Rhipicephalus sanguineus (Latreille) to infection by a Brazilian strain of Rickettsia rickettsii. Guinea pigs experimentally infected by R. rickettsii were simultaneously infested by larvae of the three tick species. Recovered engorged larvae were allowed to molt to nymphs and held in an incubator at 23 degrees C and 85-90% RH. Subsequent flat nymphs were tested for rickettsial infection by polymerase chain reaction (PCR). Concomitant infestations with sibling ticks on noninfected guinea pigs (control) were done. While 10-60% of the A. cajennense nymphs were shown to be infected by R. rickettsii, both A. aureolatum and R. sanguineus were highly susceptible to R. rickettsii, since 80-100% of their nymphs were shown to be infected in the corresponding trials. Most of the engorged larvae (approximately 70-95%), regardless of being infected or not, successfully molted to nymphs. Mortality rates for engorged larvae tended to be statistically similar (P > 0.05) for ticks recovered from R. rickettsii-infected and noninfected guinea pigs, within each tick species. The only exceptions were the significantly higher mortalities (P < 0.05) for engorged A. cajennense larvae recovered from two infected guinea pigs. Therefore, A. cajennense was less susceptible to R. rickettsii infection than A. aureolatum and R. sanguineus, while feeding on rickettsemic guinea pigs. These two later species were similarly highly susceptible.

Serosurvey of Rickettsia spp. in dogs and humans from an endemic area for Brazilian spotted fever in the State of São Paulo, Brazil.

The present study provides a rickettsial serosurvey in 25 dogs and 35 humans in an endemic area for Brazilian spotted fever in the State of São Paulo, where the tick Amblyomma aureolatum is the main vector. Testing canine and human sera by indirect immunofluorescence against four Rickettsia antigens (R. rickettsii, R. parkeri, R. felis and R. bellii) showed that 16 (64%) of canine sera and 1 (2.8%) of human sera reacted to at least one of these rickettsial antigens with titers >0r= 64. Seven canine sera and the single reactive human serum showed titers to R. rickettsii at least four times those of any of the other three antigens. The antibody titers in these 7 animals and 1 human were attributed to stimulation by R. rickettsii infection. No positive canine or human serum was attributed to stimulation by R. parkeri, R. felis, or R. bellii. Our serological results showed that dogs are important sentinels for the presence of R. rickettsii in areas where the tick A. aureolatum is the main vector of Brazilian spotted fever.

Detection of anti-Toxoplasma gondii antibodies in small wild mammals from preserved and non-preserved areas in the Caatinga biome, a semi-arid region of Northeast Brazil.

This study was conducted to determine the seroprevalence of anti-Toxoplasma gondii antibodies in 152 free-living small wild mammals from distinct regions in the Caatinga biome, a semi-arid region in the Northeast of Brazil: the National Park of Serra das Confusões (NPSC), which is a preserved area in the state of Piauí, and the municipalities of Petrolina and Lagoa Grande, two non-preserved areas in the state of Pernambuco. Using the modified agglutination test (MAT), we found that 5.3% (4/75) and 3.3% (2/60) of small wild mammals were positive for IgG anti-T. gondii antibodies in the NPSC and Petrolina, respectively. All mammals from Lagoa Grande (0/17) tested negative on the MAT. Indirect infection of T. gondii was determined by MAT in Galea spixii, Monodelphis domestica and Thrichomys laurentius (from NPSC) and in Didelphis albiventris (from Petrolina). Seropositive animals were observed in both preserved and non-preserved areas within the Caatinga biome. Low seroprevalences observed can be related to the extreme temperature and humidity in this particular biome.

Prevalence of Rickettsia infection in dogs from the urban and rural areas of Monte Negro municipality, western Amazon, Brazil.

The present study evaluated the rickettsial infection among dogs living in the rural and urban areas of Monte Negro, state of Rondônia, western Brazilian Amazon. Canine sera were tested by the indirect immunofluorescence assay (IFA) using six rickettsial antigens: Rickettsia bellii, Rickettsia amblyommii, Rickettsia rhipicephali, Rickettsia rickettsii, Rickettsia parkeri, and Rickettsia felis. While the first three Rickettsia species are known to occur in the study site, the latter three species are known to occur in southeastern Brazil. For each serum, end point titer reacting with each Rickettsia antigen was determined. Serum showing for a Rickettsia species titer at least fourfold higher than that observed for any other Ricketttsia species was considered homologous to the first Rickettsia species or to a very closely related genotype. A total of 164 rural and 153 urban dogs were tested. Overall, 19 (11.6%) and 6 (3.9%) dogs from rural and urban areas, respectively, reacted positively to at least one Rickettsia species. In the rural area, three sera showed titers to R. parkeri at least four-fold higher than any of the other five antigens. These sera were considered to be homologous to R. parkeri or a very closely related genotype. Using the same criteria, two rural sera were considered homologous to R. amblyommii, two other rural sera to R. rhipicephali, and one urban serum to R. parkeri. Because dogs living in the rural area of Monte Negro are commonly infested by the same tick species infesting humans, they indeed serve as sentinels for human rickettsial diseases. Thus, humans living in Monte Negro are likely to be infected by at least three Rickettsia species: R. parkeri, R. amblyommii, and R. rhipicephali. While R. parkeri is a known human pathogen, further studies are required to verify the potential role of R. amblyommii and R. rhipicephali as human pathogens.

Rickettsial infection in capybaras (Hydrochoerus hydrochaeris) from São Paulo, Brazil: serological evidence for infection by Rickettsia bellii and Rickettsia parkeri.

INTRODUCTION: In Brazil, capybaras (Hydrochoerus hydrochaeris) are important hosts for Amblyomma ticks, which in turn can transmit rickettsiae to humans and animals. Therefore, capybaras are potential sentinels for rickettsial infection. OBJECTIVE: The present study evaluated rickettsial infection in capybaras in different areas of the state of São Paulo, where rickettsiosis has never been reported. Materials and methods. Blood sera from 73 capybaras from six localities in São Paulo were tested by indirect immunofluorescence assay using Rickettsia rickettsii, Rickettsia parkeri, and Rickettsia bellii antigens. Capybara spleens were tested by PCR, targeting a fragment of the rickettsial gltA gene. Ticks were collected from each capybara sample and taxonomically identified to species. RESULTS: A total of 94 positively reacting capybara samples, 19 (26.0%), 25 (34.2%), and 50 (68.5%) capybara sera reacted to R. rickettsii, R. parkeri, and R. bellii, respectively. Twenty-five capybara sera showed titers to R. bellii at least four-fold higher than to any of the other two antigens. These sera were considered homologous to R. bellii. Using the same criteria, 3 capybara sera were considered homologous to R. parkeri. No sera were be considered homologous to R. rickettsii. No rickettsial DNA was detected in capybara spleen samples. Ticks collected on capybaras were Amblyomma dubitatum and Amblyomma cajennense. CONCLUSIONS: The first evidence is reported of R. bellii natural infection in vertebrate hosts, and the first evidence of R. parkeri infection in capybaras. While R. parkeri is known to infect and cause disease in humans, no similar evidence for human infection has been indicated by R. bellii.

Natural infection, transovarial transmission, and transstadial survival of Rickettsia bellii in the Tick Ixodes loricatus (Acari: Ixodidae) from Brazil.

An Ixodes loricatus engorged female, infected with Rickettsia bellii, was collected from an opossum (Didelphis aurita) in Mogi das Cruzes, São Paulo State, Brazil. Two consecutive laboratory tick generations (F(1) and F(2)) reared from this single engorged female were evaluated for Rickettsia infection by polymerase chain reaction (PCR) targeting specific Rickettsia genes. Immature ticks fed on naïve Wistar rats (Rattus norvegicus) and adult ticks fed on opossum (D. aurita), both free of ticks and rickettsial infection. PCR performed on individual ticks from the F(1) (20 larvae, 10 nymphs, and 10 adults) and the F(2) (30 larvae, 30 nymphs, and 15 adults) yielded expected bands compatible with Rickettsia. All the PCR products that were sequenced, targeting gltA gene, resulted in sequences identical to each other and 99.7% (349/350) similar to the corresponding sequence of R. bellii in GenBank. The R. bellii infection on ticks from the second laboratory generation (F(2)) was confirmed by other PCR protocols and successful isolation of R. bellii in cell culture. We report for the first time a Rickettsia species infecting I. loricatus, and the first report of R. bellii in the tick genus Ixodes. We conclude that there was an efficient transovarial transmission and transstadial survival of this Rickettsia species in the tick I. loricatus. Our results suggest that R. bellii might be maintained in nature solely by transovarial transmission and transstadial survival in ticks (no amplifier vertebrate host is needed), since there has been no direct or indirect evidence of infection of vertebrate hosts by R. bellii.

Prevalence of Rickettsia felis in the fleas Ctenocephalides felis felis and Ctenocephalides canis from two Indian villages in Sao Paulo Municipality, Brazil.

We evaluated the presence of Rickettsia infection among fleas collected on domestic dogs in two Guarani Indian communities in the suburban area of São Paulo Municipality, Brazil. A total of 114 Ctenocephalides felis felis and 47 Ctenocephalides canis were collected from 40 dogs. A total of 41 C. felis felis (36.0%) and 9 C. canis (19.1%) fleas yielded expected bands by PCR, which were all shown by DNA sequencing to be indentical to the corresponding sequence of a fragment of the Rickettsia felis gltA gene deposited in GenBank. The overall prevalence of R. felis was 31.0% (49/161).

A new argasid tick species (Acari: Argasidae) associated with the rock cavy, Kerodon rupestris Wied-Neuwied (Rodentia: Caviidae), in a semiarid region of Brazil.

BACKGROUND: The rock cavy Kerodon rupestris (Wied-Neuwied, 1820) is a rodent species endemic to northeastern Brazil. Earlier studies have associated the argasid tick Ornithodoros talaje (Guérin-Méneville, 1849) with rocky cavy; however, a recent study proposed that O. talaje is not established in Brazil, where previous reports of this species were possibly misidentifications of closely related species, yet to be properly determined. Here, we describe a new species of Ornithodoros Koch, 1844 associated with rock cavies in northeastern Brazil. METHODS: During 2012-2013, Ornithodoros ticks were collected from K. rupestris resting places in Paraíba State (PB) and Piauí State (PI), northeastern Brazil. These ticks were brought alive to the laboratory, and used to form two laboratory colonies (PB and PI ticks). Field-collected adults and laboratory-reared larvae were used for morphological description through light and scanning electron microscopy. DNA sequences of the mitochondrial 16S rRNA gene were generated from nymphal ticks and used to conduct phylogenetic analyses along with other Ornithodoros spp. sequences from GenBank. Reproductive compatibility of crosses between PB and PI adult ticks was evaluated, as well as analyses of hybrid ticks through larval morphology by a principal components analysis (PCA) and DNA sequences of the second internal transcribed spacer (ITS2) region from adult ticks. RESULTS: Morphological analysis allowed recognizing these ticks as a new species, Ornithodoros rietcorreai n. sp. The larva of O. rietcorreai is distinct from those of other Ornithodoros spp. by the combination of the following character states: 14 pairs of dorsal setae, dorsal plate pyriform, hypostome with pointed apex and dental formula 3/3 anteriorly, 2/2 posteriorly, and anal valves with long and pointed leaf-shaped ends. There were a few larval morphological differences between PB and PI ticks, and their mitochondrial 16S rDNA sequences diverged by 3.3 %. On the other hand, cross-mating experiments showed that PB and PI ticks were reproductive compatible, indicating that they represent a single species. Analyses of ITS2 sequences and PCA corroborated this assumption. CONCLUSION: Ornithodoros rietcorreai is described as a new species associated with K. rupestris in Brazil, increasing the Brazilian tick fauna to 70 species.

Isolation of the Pathogen Rickettsia sp. Strain Atlantic Rainforest From Its Presumed Tick Vector, Amblyomma ovale (Acari: Ixodidae), From Two Areas of Brazil.

In this study, Amblyomma ovale Koch ticks were collected from domestic dogs in two localities of the Atlantic rainforest biome of Brazil: 1) the Paty Valley of the Chapada Diamantina National Park, Bahia state (northeastern Brazil), and 2) Adrianópolis, Paraná state (southern Brazil). Ticks were screened for the presence of Rickettsia-like structures by the hemolymph test with Giménez staining, and then processed for isolation of rickettsiae in Vero cell culture by the shell-vial technique. Rickettsiae were isolated from one A. ovale tick of each of the two localities. The two isolates were successfully established in the laboratory with several passages, each one reaching >90% infection of the cells. The two isolates were identified as the spotted fever group (SFG) agent Rickettsia sp. strain Atlantic rainforest, as their gltA (350 bp), ompB (781 bp), and ompA (567 bp) gene fragments were 100% equal to GenBank corresponding sequences of the original strain Atlantic rainforest, reported to be infecting a human in southeastern Brazil, and also 100% equal to the available ompA sequence of strain Bahia, reported to be infecting a human in Paty Valley, the same area of the present study in Bahia state. Ten dogs from Paty Valley were serologically tested against rickettsial antigens by the indirect immunofluorescence antibody test. At least 60% of them were seroreactive to SFG rickettsiae. The role of A. ovale as vector of Rickettsia sp. strain Atlantic rainforest in the Paty Valley area, as well as in other parts of Latin America, is discussed.

Epidemiological aspects and risk factors for infection by Leishmania infantum chagasi in dogs from municipality of Petrolina, Northeastern Brazil.

Visceral leishmaniasis (VL) is a disease of great concern for public health because of its high incidence and lethality. Here, we performed a serologic study of domestic dogs in the municipality of Petrolina in northeastern Brazil to evaluate the possible risk factors associated with canine seropositivity for Leishmania infantum chagasi. Blood samples from 1245 dogs in urban and rural areas were collected and examined by indirect immunofluorescent antibody test (IFAT) and an indirect enzyme-linked immunosorbent assay (ELISA). The dogs were subjected to physical examination and classified according to their clinical manifestations. A questionnaire was administered to the owners to detect potential risk factors for infection with Leishmania spp. using logistic regression models. Of the 1245 dogs evaluated, 11.2% (140/1245) were seropositive in both tests (CI 95%: 9.5% to 13.1%). Approximately 60.7% of the reactive dogs were clinically suspect, with lymphadenomegaly, cutaneous ulcerations, onychogryphosis, pale mucous membranes and alopecia being the most obvious symptoms of infection. The seroprevalences in urban and rural areas were 5.4% (CI 95%: 4% to 7.1%) and 23.6% (CI 95%: 19.5% to 28.1%), respectively. The possible risk factors for the presence of anti L. infantum chagasi antibodies were the presence of a green area close to the home of the animal (OR=3.63; p<0.001), a mongrel breed (OR=2.11; p=0.025) and male gender (OR=1.51, p=0.034). The seroprevalence of L. infantum chagasi in the canine population is distributed in a heterogeneous manner, with a higher prevalence in rural areas.