Study on coinfecting vector-borne pathogens in dogs and ticks in Rio Grande do Norte, Brazil

Quantitative Detection of Leishmania in Rhipicephalus microplus and Amblyomma sabanerae in the Peruvian Amazon Basin

Leishmaniasis is a disease of public importance with a complex transmission cycle. A quantitative PCR was developed by using the small subunit of the ribosomal RNA gene (SSU rRNA) as a DNA target, which is conserved in all Leishmania species. A TaqMan ^® probe was designed to have a high specificity. In all, 22 out of 23 (95.7%) ticks classified as R. microplus tested positive for Leishmania sp. The quantification was between 34.1 and 2197.1 parasites per tick in a range of 12 to 769 fg/uL. In addition, 9 out of 10 (90%) ticks classified as Amblyomma sabanerae tested positive for Leishmania sp. The quantification was between 448.6 and 5428.6 parasites per tick in a range of 157 to 1900 fg/µL. Leishmania sp. was identified in very high percentages in Rhipicephalus microplus and Amblyomma sabanerae from wild Pecari tajacu and Chelonoidis denticulata, in quantities of 34.1 and 5428.6 parasites per arthropod, and this could suggest that the ticks were parasitized by sucking blood from the animals from which they were collected. This is the first report about Leishmania parasites found in wild Rhipicephalus microplus and Amblyomma sabanerae, adding new information about the distribution and epidemiology of the parasite in sylvatic areas.

Ticks and Associated Pathogens From Rescued Wild Animals in Rainforest Fragments of Northeastern Brazil

The Ixodidae family comprises ticks that are hematophagous ectoparasites and are considered vectors of several hemoparasites from the Anaplasmataceae family and the genus Hepatozoon, Babesia, and Rickettsia. These ectoparasites parasitize domestic and wild animals belonging to several vertebrate groups. Ticks are highly adapted to different biomes and thus possess a wide geographical distribution. In the Brazilian state of Bahia, localized in the Northeast region, there are large rainforest fragments. Studies have rarely been carried out on ticks, and their hemoparasites, that parasitize wild animals in this region. Thus, this study aimed to identify the tick species parasitizing wild animals rescued in rainforest fragments of Bahia and investigate the presence of hemoparasites in tick tissues. During a 2-year period, 238 ticks were collected from 41 wild mammalians, reptiles, and amphibians. These ectoparasites were taxonomically classified according to their morphological characteristics. The ticks identified belonged to five different species from the Ixodidae family: Amblyomma varium, Amblyomma rotundatum, Amblyomma nodosum, Ixodes loricatus, and Rhipicephalus sanguineus. For the first time, an A. rotundatum parasitizing the Mesoclemmys tuberculata turtle was described. PCR assays using DNA extracted from salivary glands or midgut of the ticks were performed to detect specific DNA fragments of hemoparasites from the genus Rickettsia, Ehrlichia, Babesia, Hepatozoon, and from the Anaplasmataceae family. The results showed positive detection of the Rickettsia genus (7.9%), Anaplasmataceae family (15.8%), and Hepatozoon genus (15.8%). Specific DNA from the Ehrlichia and Babesia genera were not detected in these samples. Specific DNA from members of the Anaplasmataceae family was detected in A. varium for the first time. The present work showed that amphibians, reptiles, and mammals from Bahia's Atlantic Forest areparasitized by different tick species, and that these ectoparasites present pathogens in their tissues that impact both humans and animals due to their zoonotic potential.

Low genetic diversity of Ehrlichia canis associated with high co-infection rates in Rhipicephalus sanguineus (s.l.)

BACKGROUND

Rhipicephalus sanguineus sensu lato (s.l.) is the most widely distributed ixodid tick and is a vector of major canine and human pathogens. High-throughput technologies have revealed that individual ticks carry a high diversity of pathogens, including bacteria, protozoa and viruses. Currently, it is accepted that co-infections (multiple pathogen species within an individual) are very common in ticks and influence pathogen acquisition and transmission as well as host infection risk. However, little is known on the impact of the genetic diversity of pathogens on the incidence of co-infections. Herein, we studied the frequency of co-infections in R. sanguineus (s.l.) and their association with the genetic diversity of Ehrlichia canis.

METHODS

Rhipicephalus sanguineus (s.l.) female ticks (n = 235) were collected from healthy farm dogs in three districts of Pakistan. Microfluidic real-time PCR, a powerful nanotechnology for high-throughput molecular detection of pathogens, was used to test the presence of 25 bacterial and seven parasitic species in individual ticks. The genetic diversity of E. canis was evaluated by characterizing the trp36 gene.

RESULTS

A total of 204 ticks were infected with at least one pathogen and 109 co-infected with two (80%) or three (20%) pathogens. Rickettsia massiliae (human pathogen) and E. canis (zoonotic dog pathogen) were the most common pathogens co-infecting (30.4%) ticks. Furthermore, all identified co-infections included R. massiliae and/or E. canis. Multiple correspondence analysis (MCA) revealed that single infections did not show clear regional association whereas some co-infections were restricted to certain geographical regions. The sequence analysis of trp36 in representative samples allowed the identification of three E. canis strains with low genetic diversity, and the strain found in Muzaffargarh district appeared to be more adapted to co-infection with R. massiliae.

CONCLUSIONS

Rhipicephalus sanguineus (s.l.) harbors multiple co-infections with human and dog pathogens of zoonotic potential. Findings of this study suggest that genetic diversity of E. canis may favor co-infections with different pathogens.

Occurrence of Ehrlichia canis and Hepatozoon canis and probable exposure to Rickettsia amblyommatis in dogs and cats in Natal, RN

Occurrence of infection or exposure to Ehrlichia canis, Hepatozoon canis and Rickettsia spp. was detected in feral cats living in two fragments from Atlantic rainforest, in Natal, RN, Brazil, and in dogs living around the parks. While serum samples were collected from 155 animals (53 cats living in the parks; 29 dogs living in human homes around the parks; and 73 dogs living at an animal control center - ACC), spleen samples were collected from 20 dogs that were euthanized at ACC. Serum samples were analyzed to Rickettsia spp. and E. canis antibodies using the indirect immunofluorescence assay. Seventeen of the 102 dogs (17%) had E. canis antibodies and 13% (20/155) of all dogs and cats (i.e. 3% (3/102) of the dogs and 32% (17/53) of the cats) were seropositive for Rickettsia spp. antigens. The animals were therefore been exposed to R. amblyommatis or by a very closely related genotype. Among the 20 dog spleen samples analyzed, eight were PCR positive for E. canis and two for H. canis (GenBank accession number MG772657 and MG772658, respectively). In none of the spleen samples were obtained amplicons for Babesia spp. through PCR. This study provided the first evidence that Rickettsia of the spotted fever group is circulating among dogs and cats in Natal.

Detection of Anaplasmataceae agents and co-infection with other tick-borne protozoa in dogs and Rhipicephalus sanguineus sensu lato ticks

Anaplasmosis and ehrlichiosis are of serious health concern worldwide for animals and humans. In the present study, we report the occurrence of Anaplasma platys and Ehrlichia canis in dogs and Rhipicephalus sanguineus sensu lato (s.l.) ticks from Peninsular Malaysia using a nested polymerase chain reaction assay based on amplification of the 16S rRNA gene. Anaplasma platys was detected from dogs and ticks with prevalence rates of 3.3% (8/240) and 2.9% (4/140), respectively. On the other hand, 12.9% (31/240) of the dogs and 0.7% (1/140) of the ticks were tested positive for E. canis. Additionally, co-infections of A. platys and E. canis with Babesia or Hepatozoon protozoa were also noted in this study. Double infection (E. canis + B. gibsoni) was observed in tick, whereas triple infections (E. canis + A. platys + B. vogeli and E. canis + A. platys + H. canis) were found in dogs. This study represents the first evidence of A. platys DNA in R. sanguineus s.l. in Malaysia.

Tick-borne infections in dogs and horses in the state of Espírito Santo, Southeast Brazil

This work aims to identify and quantify the percentage of Rickettsia spp., Ehrlichia spp., Babesia spp. and Hepatozoon spp. positive pet dogs, and to identify ticks collected on these animals in the state of Espírito Santo, in the Southeast region of Brazil. The study included 378 dogs, 226 females and 152 males, of various breeds and ages (mean age of 4.1 years). All animals were examined for ticks, and whole blood was collected and processed by conventional PCR protocols for Babesia spp., Anaplasmataceae, Hepatozoon spp. and by real-time PCR for Ehrlichia canis. Of the 378 dogs examined, 157 (41.53%) had ticks at the time of the study, which were identified as R. sanguineus s.l. in 154 animals (98.10%), Amblyomma ovale in one animal (0.63%), and Amblyomma sculptum in 2 animals (1.27%). In the PCR for Babesia spp., 5 animals (1.32%) were positive, producing DNA sequences 100% identical to Babesia vogeli. For Anaplasmataceae, 34 animals (9%) were positive, 10 of which generated DNA sequences 100% similar to Ehrlichia canis. The other 24 samples generated fragments 100% identical to Anaplasma platys. In the PCR for Hepatozoon spp, 39 animals (10.31%) were positive, producing sequences 100% identical to Hepatozoon canis. Finally, in the real-time PCR specific for E. canis, 28 animals (7.40%) were positive. Coinfection with 2 or 3 agents was observed in 20 animals (5.29%). Of the 378 dogs sampled, 312 were analyzed by indirect immunofluorescence assay (IFA) for E. canis and five species of Rickettsia (R. rickettsii, R. parkeri, R. amblyommatis, R. rhipicephali and R. bellii). Among them, 71 dogs (22.75%) had a positive reaction for E. canis and 16 dogs (5.13%) had antibody titers higher than 64 to at least one Rickettsia species, 5 of them (1.60%) to R. rickettsii. Samples of blood were collected from 10 equines in the regions where dogs were found with positive serology for any one of the Rickettsia sp. tested. In the municipality of Vila Velha, two equines were positive for R. bellii with inverse titers of 64 and 128. These results indicate that tick-transmitted agents, such as E. canis, A. platys, B. vogeli, H. canis, and several spotted fever group Rickettsia are circulating in the canine population of the Brazilian state of Espirito Santo.

Co-infection with arthropod-borne pathogens in domestic cats

Abstract The role of several feline vector-borne pathogens (FVBP) as a cause of disease in cats has not been clearly determined. In fact, with the exception of Bartonella spp. and hemoplasmas, FVBP in cats has not been clearly determined in Brazil yet. The present study aimed at identifying, by using molecular methods, the presence of FVBP in three cats showing non-specific clinical signs and inclusions suggestive of hemoparasites in blood smears. Cytauxzoon felis, ‘Candidatus Mycoplasma haemominutum’, Ehrlichia sp. closely related to Ehrlichia canis, and Anaplasma sp. closely related to Anaplasma phagocytophilum were detected in blood samples from two out of three sampled cats. Both cats positive for multiple FVBP did not show hematological and biochemical abnormalities. The present work emphasizes the need for molecular confirmation of co-infection by multiple FVBP in cats presenting non-specific clinical signs and inclusions resembling hemoparasites in blood smears.

Detection of Leishmania (V) guyanensis in Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) collected from Pecari tajacu

INTRODUCTION

Previous studies identified the presence of Leishmania infantum in Rhipicephalus sanguineus and indicated the possibility that it could transmit leishmaniasis to a variety of hosts.

OBJECTIVE

To identify parasites of Leishmania (Viannia) spp. in ticks collected from wild animals in an endemic area for leishmaniasis.

MATERIALS AND METHODS

We performed 81 individual DNA extractions from ticks collected from three Tapirus terrestris and three Pecari tajacu in Madre de Dios, Perú. Ticks were taxonomically identified and they were subsequently prepared to identify Leishmania (Viannia) spp. kDNA by PCR and the species of Leishmania by HRM-PCR.

RESULTS

Leishmania (Viannia) kDNA was detected in three wild ticks of the species R. microplus, collected from a collard peccary (P. tajacu) hunted in the forests of Madre de Dios. The HRM-PCR showed that one of the positive samples had a kDNA curve compatible with L. (V) guyanensis.

CONCLUSION

The results showed the presence of L. (V) guyanensis DNA in R. microplus possibly acquired after biting a collarde peccary. Therefore, it is important to design future studies to clarify R. microplus involvement in the transmission of leishmaniasis.

Hepatozoon canis and Leishmania spp. coinfection in dogs diagnosed with visceral leishmaniasis

This study describes the occurrence of dogs naturally co-infected with Hepatozoon canis and two Leishmania species: L. infantum or L. braziliensis. Four dogs serologically diagnosed with Visceral Leishmaniasis were euthanized. Liver and spleen samples were collected for histopathological analysis and DNA isolation. H. canis meronts were observed in tissues from all four dogs. H. canis infection was confirmed by PCR followed by sequencing of a fragment of 18S rRNA gene. Leishmania detection and typing was confirmed by ITS1' PCR-RFLP and parasite burden was calculated using ssrRNA quantitative qPCR. A DPP - Dual Path platform test was performed. One out (Dog #2) of four animals was asymptomatic. Dogs #1 and #4 were infected by L. infantum and were DPP test positive. Dogs #2 and #3 were infected by L. braziliensis and were DPP test negative. Furthermore, visceral dissemination was observed in Dogs #2 and #3, since L. braziliensis was detected in liver and spleen samples. The visceral dissemination of L. braziliensis associated with systemic signs suggested that this co-infection could influence the parasite burden and disease progression.

Molecular identification of Hepatozoon canis in dogs from Campo Grande, Mato Grosso do Sul, Brazil

The aim of this study was to investigate the occurrence of Hepatozoon species infecting dogs in the municipality of Campo Grande, Mato Grosso do Sul (MS), Brazil, using blood samples (n = 165) drawn from dogs. The species Hepatozoon caniswas identified in 3.63% of the tested animals using molecular tools. Further studies are needed to determine the clinical relevance of this infection and the main arthropod vectors involved in its transmission.