Molecular epidemiology of the emerging zoonosis agent Anaplasma phagocytophilum (Foggie, 1949) in dogs and ixodid ticks in Brazil

Dogs (Canis familiaris) as sentinels for determining the risk of occurrence of Rickettsia spp. and Anaplasma phagocytophilum in previously undiagnosed areas

Determining the occurrence of Rickettsia spp. and Anaplasma phagocytophilum in municipalities with no case records is important to define surveillance strategies and is essential to reduce lethality in different regions. Therefore, an approach aimed at enhancing surveillance in municipalities with an unknown epidemiological situation was tested, according to the classification suggested by Resolution SMA/SES 07/01/16. Canine sera collected in the annual anti-rabies campaign were submitted to the indirect fluorescent antibody test for Rickettsia amblyommatis, R. belli, R. parkeri, R. rickettsii and A. phagocytophilum. Titers ≥1:64 and ≥1:320 were considered positive for Rickettsia spp. and A. phagocytophilum, respectively. For Rickettsia spp., 61.8% of dogs were seropositive, with 26% positive for more than one species, and 42.3% were seropositive for R. rickettsii. Dogs from the urban area presented 5.16 (CI 1.18; 7.69) times greater odds of seropositivity for R. parkeri (p = 0.037) and 3.39 (CI 1.04; 3.70) times greater odds for R. belli (p = 0.017). Considering the 1:40 cutoff point, 19.1% of dogs were reactive for A. phagocytophilum. Two (1%) dogs in rural areas were positive (titer 1:640). The results indicate all species ever tested in Lavras/MG, since the present study is the city's first report on the subject. According to classifications of the aforementioned Resolution, the results determine that the municipality of Lavras should be considered a "risk area" for Brazilian spotted fever(BSF). The methodology presented is efficient, straight forward to perform and inexpensive for diagnosing a risk situation for BSF and human granulocytic anaplasmosis. Moreover, its use can be applied throughout Brazil and other countries as a public health alert guideline.

Molecular detection and phylogeny of Anaplasma spp. closely related to Anaplasma phagocytophilum in small ruminants from China

The genus Anaplasma comprises eight bacterial species that are obligate intracellular pathogens that affect human and animal health. The zoonotic species A. phagocytophilum is the causative agent of tick-borne fever in ruminants, and of granulocytic anaplasmosis in horses, dogs, and humans. Recently, novel strains related to A. phagocytophilum (A. phagocytophilum-like 1/Japanese variant and A. phagocytophilum-like 2/Chinese variant) have been identified. The aim of this study was to reveal the prevalence and phylogeny of A. phagocytophilum and related stains in small ruminants and ticks in China based on sequences of the 16S rRNA combined restriction fragment length polymorphism (RFLP) and groEL genes. PCR-RFLP and phylogenetic analyses based on the 16S rRNA gene showed the presence of A. phagocytophilum-like 1 and 2 variants in sampled animals from China, with prevalence rates of 22.6% (303/1338) and 0.7% (10/1338), respectively. Only A. phagocytophilum-like 1 DNA was found in Haemaphysalis longicornis. The phylogeny based on the groEL gene showed inclusion of A. phagocytophilum-like 1 and some A. phagocytophilum-like 2 strains in two unique clades distinct from, but related to, Japanese and Chinese strains of related A. phagocytophilum, respectively. One noteworthy result was that the SSAP2f/SSAP2r primers detected Ehrlichia spp. strains. Moreover, the A. phagocytophilum-like 1 and 2 strains should be considered in the differential diagnosis of caprine and ovine anaplasmosis. Further investigations should be conducted to provide additional epidemiological information about A. phagocytophilum and A. phagocytophilum-like variants in animals and ticks.

Ticks and Tick-Borne Pathogens in Domestic Animals, Wild Pigs, and Off-Host Environmental Sampling in Guam, USA

Background: Guam, a United States of America (USA) island territory in the Pacific Ocean, is known to have large populations of ticks; however, it is unclear what the risk is to wildlife and humans living on the island. Dog (Canis familiaris), cat (Felis catus), and wild pig (Sus scrofa) sentinels were examined for ticks, and environmental sampling was conducted to determine the ticks present in Guam and the prevalence of tick-borne pathogens in hosts.

Methods and Results: From March 2019-November 2020, ticks were collected from environmental sampling, dogs, cats, and wild pigs. Blood samples were also taken from a subset of animals. A total of 99 ticks were collected from 27 environmental samples and all were Rhipicephalus sanguineus, the brown dog tick. Most ticks were collected during the dry season with an overall sampling success rate of 63% (95% CI: 42.4–80.6). 6,614 dogs were examined, and 12.6% (95% CI: 11.8–13.4) were infested with at least one tick. One thousand one hundred twelve cats were examined, and six (0.54%; 95% CI: 0.20–1.1) were found with ticks. Sixty-four wild pigs were examined and 17.2% (95% CI: 9.5–27.8) had ticks. In total, 1,956 ticks were collected and 97.4% of ticks were R. sanguineus. A subset of R. sanguineus were determined to be the tropical lineage. The other tick species found were Rhipicephalus microplus (0.77%), Amblyomma breviscutatum (0.77 %), and a Haemaphysalis sp. (0.51%). Blood samples from 136 dogs, four cats, and 64 wild pigs were tested using polymerase chain reaction (PCR) and DNA sequencing methods. Five different tick-borne pathogens with the following prevalences were found in dogs: Anaplasma phagocytophilum 5.9% (95% CI: 2.6–11.3); Anaplasma platys 19.1% (95% CI: 12.9–26.7); Babesia canis vogeli 8.8% (95% CI: 4.6–14.9); Ehrlichia canis 12.5% (95% CI: 7.5–19.3); Hepatozoon canis 14.7% (95% CI: 9.2–28.8). E. canis was detected in one cat, and no tick-borne pathogens were detected in wild pigs. Overall, 43.4% (95% CI: 34.9–52.1) of dogs had at least one tick-borne pathogen. Serological testing for antibodies against Ehrlichia spp. and Anaplasma spp. showed prevalences of 14.7% (95% CI: 9.2–28.8) and 31.6% (95% CI: 23.9–40), respectively.

Conclusion: Four different tick species were found in Guam to include a Haemaphysalis sp., which is a previously unreported genus for Guam. Dogs with ticks have a high prevalence of tick-borne pathogens which makes them useful sentinels.

Spatial distribution and molecular epidemiology of Babesia vogeli in household dogs from municipalities with different altitude gradients in the state of Rio de Janeiro, Brazil

We performed a cross-sectional epidemiological study with 456 household dogs from urban and rural areas in two different regions situated at different altitudes in the state of Rio de Janeiro. The PCR technique using 18S rRNA as target revealed prevalence of 7.9% of dogs positive for piroplasmids. These samples were sequenced, and all the sequences were 99.9% to 100% similar to Babesia vogeli sequences from other countries. The spatial distribution of positive cases was analysed using kernel interpolation in the QGIS software, and the spatial correlation indicators among positive dogs, altitude, and presence of ticks were obtained by calculating the local Moran index using the GeoDa software. The spatial correlation between positive cases and altitude was clear based on both visual and statistical observations. Logistic regression applying the Wald method with a cutoff point of 0.1 revealed that dogs from a region with altitude <600 m had a 2.29-fold chance of B. vogeli infection (OR = 2.29; p-value = 0.04; CI: 1.03-5.07), while the rainy season was 2.45 times more associated with B. vogeli infection (OR = 2.45; p-value = 0.01; CI: 1.20-5.01), and dogs infested with Rhipicephalus sanguineus sensu lato had a 2.47 times higher chance of being infected (OR = 2.47; p-value = 0.02; CI: 1.13-5.38). Entropy analysis of the alignment between B. vogeli 18S rRNA (> 1.600 bp) sequences revealed that the most variable region corresponds to the hypervariable V4 region. Genetic homogeneity was observed among the B. vogeli 18S rRNA sequences, with distance values ranging from 0 to 0.007 and a mean value of 0.001. The evolutionary distance (0.003) was greater between the sequences from the municipalities of Barra do Pirai (low altitude) and Teresopolis (high altitude). This study expands the molecular epidemiologic knowledge of B. vogeli and shows points of variability in the B. vogeli 18S rRNA. The results indicate the potential use of spatial analysis tools to improve screening for positive cases, enabling more in-depth studies to strengthen understanding of tick infection prevention in dogs.

Epidemiological and Clinicopathological Features of Anaplasma phagocytophilum Infection in Dogs: A Systematic Review

Anaplasma phagocytophilum is a worldwide emerging zoonotic tick-borne pathogen transmitted by Ixodid ticks and naturally maintained in complex and incompletely assessed enzootic cycles. Several studies have demonstrated an extensive genetic variability with variable host tropisms and pathogenicity. However, the relationship between genetic diversity and modified pathogenicity is not yet understood. Because of their proximity to humans, dogs are potential sentinels for the transmission of vector-borne pathogens. Furthermore, the strong molecular similarity between human and canine isolates of A. phagocytophilum in Europe and the USA and the positive association in the distribution of human and canine cases in the USA emphasizes the epidemiological role of dogs. Anaplasma phagocytophilum infects and survives within neutrophils by disregulating neutrophil functions and evading specific immune responses. Moreover, the complex interaction between the bacterium and the infected host immune system contribute to induce inflammatory injuries. Canine granulocytic anaplasmosis is an acute febrile illness characterized by lethargy, inappetence, weight loss and musculoskeletal pain. Hematological and biochemistry profile modifications associated with this disease are unspecific and include thrombocytopenia, anemia, morulae within neutrophils and increased liver enzymes activity. Coinfections with other tick-borne pathogens (TBPs) may occur, especially with Borrelia burgdorferi, complicating the clinical presentation, diagnosis and response to treatment. Although clinical studies have been published in dogs, it remains unclear if several clinical signs and clinicopathological abnormalities can be related to this infection.

Genetic diversity of Anaplasma bacteria: Twenty years later

The genus Anaplasma (family Anaplasmataceae, order Rickettsiales) includes obligate intracellular alphaproteobacteria that multiply within membrane-bound vacuoles and are transmitted by Ixodidae ticks to vertebrate hosts. Since the last reclassification of Anaplasmataceae twenty years ago, two new Anaplasma species have been identified. To date, the genus includes eight Anaplasma species (A. phagocytophilum, A. marginale, A. centrale, A. ovis, A. bovis, A. platys, A. odocoilei, and A. capra) and a large number of unclassified genovariants that cannot be assigned to known species. Members of the genus can cause infection in humans and a wide range of domestic animals with different degrees of severity. Long-term persistence which, in some cases, is manifested as cyclic bacteremia has been demonstrated for several Anaplasma species. Zoonotic potential has been shown for A. phagocytophilum, the agent of human granulocytic anaplasmosis, and for some other Anaplasma spp. that suggests a broader medical relevance of this genus. Genetic diversity of Anaplasma spp. has been intensively studied in recent years, and it has been shown that some Anaplasma spp. can be considered as a complex of genetically distinct lineages differing by geography, vectors, and host tropism. The aim of this review was to summarize the current knowledge concerning the natural history, pathogenic properties, and genetic diversity of Anaplasma spp. and some unclassified genovariants with particular attention to their genetic characteristics. The high genetic variability of Anaplasma spp. prompted us to conduct a detailed phylogenetic analysis for different Anaplasma species and unclassified genovariants, which were included in this review. The genotyping of unclassified genovariants has led to the identification of at least four distinct clades that might be considered in future as new candidate species.

Molecular screening for tick-borne bacteria and hematozoa in Ixodes cf. boliviensis and Ixodes tapirus (Ixodida: Ixodidae) from western highlands of Panama

The first molecular screening for Rickettsia, Anaplasma, Ehrlichia, Borrelia, Babesia and Hepatozoon was carried out in questing Ixodes cf. boliviensis and Ixodes tapirus from Talamanca Mountains, Panama, using specific primers, sequencing and phylogeny. Phylogenetic analyses for the microorganisms in Ixodes cf. boliviensis confirmed the presence of Rickettsia sp. strain IbR/CRC endosymbiont (26/27 ticks), three genotypes of the Borrelia burgdorferi (sensu lato) complex (4/27 ticks), Babesia odocoilei (1/27 ticks), and Hepatozoon sp. (2/27 ticks), tentatively designated Hepatozoon sp. strain Chiriquensis. Phylogenetic analyses for the microorganisms in I. tapirus revealed an undescribed Rickettsia sp., tentatively designated Rickettsia sp. strain Itapirus LQ (6/6 ticks), and Anaplasma phagocytophilum (2/6 ticks). To the best of our knowledge, this is the first report of B. burgdorferi (s.l.) complex, A. phagocytophilum, B. odocoilei, and Hepatozoon sp. in Ixodes ticks from Central America, and also the first detection of Rickettsia spp. in Ixodes species in Panama. In light of the importance of these findings, further studies are needed focusing on the role of I. tapirus and I. cf. boliviensis as vectors, and the vertebrates acting as reservoirs.

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Free-living adult Ixodes ticks collected in Talamanca Mountains, Panama, were PCR-screened for tick-borne pathogens.

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Ixodes tapirus and Ixodes cf. boliviensis identified morphologically and molecularly.

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Genetic differences between Ixodes boliviensis from South America and I. cf. boliviensis from Panama.

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First molecular data for B. burgdorferi (s.l.), Hepatozoon and Babesia odocoilei in I. cf. boliviensis from Central America.

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First molecular data for Anaplasma phagocytophilum and spotted fever group Rickettsia in I. tapirus from Central America.

Rickettsial pathogens circulating in urban districts of Rio de Janeiro, without report of human Brazilian Spotted Fever

Spotted fever group rickettsioses are emerging diseases. In some of these diseases, domestic dogs act as sentinels. Canine serological studies have demonstrated that rickettsial dispersion is concentrated in rural areas, seroprevalence being higher where human rickettsioses are endemic. In Rio de Janeiro, the Atlantic forest vegetation has been devastated by urbanization. In this context, we aimed to detect Rickettsia spp. in urban areas of the West Zone of Rio de Janeiro. Sera from 130 dogs were tested by Indirect Immunofluorescence Assay, and ticks collected from these dogs were tested by polymerase chain reaction. We found the rate of serological reactions against R. rickettsii and R. parkeri in our study area to exceed those of rural and non-endemic areas, highlighting the importance of dogs as urban sentinels. The possibility of contact with opossums and capybaras increased the chances of exposure to Rickettsia spp., reinforcing the hypothetical link between the landscape and the rickettsial wild cycle. Rhipicephalus sanguineus sensu lato was the tick most frequently observed. PCR-positive samples showed similarity with R. rickettsii and R. felis, an emerging pathogen rarely reported from ticks. We observed that rickettsiae circulate in urban places and ticks from indoor environments, which may be involved in bacterial epidemiology.

Prevalence and incidence of vector-borne pathogens in unprotected dogs in two Brazilian regions

Background

Various vector-borne pathogens (VBPs) affect dogs worldwide, with their diversity and force of infection being usually higher in the tropics. Cross-sectional studies have been conducted to investigate the prevalence of VBPs in dogs, but data from longitudinal studies are scarce. Herein, we assessed the prevalence and the year-crude incidence (YCI) of Leishmania spp. and other VBPs in privately-owned dogs from two geographical regions of Brazil.

Methods

A total of 823 dogs were initially screened for Leishmania spp. by both serology and polymerase chain reaction (PCR). From the negatives, 307 (103 from São Joaquim de Bicas, Minas Gerais, and 204 from Goiana, Pernambuco) were randomly selected for the longitudinal study. These dogs were tested for various VBPs at baseline, after 8 and 12 months.

Results

Out of 823 dogs initially screened, 131 (15.9%) were positive for Leishmania spp. Out of the 307 dogs enrolled in the longitudinal study, 120 (39.1%) were lost for different reasons (e.g. animal death, owner decision, and lost to follow-up). In São Joaquim de Bicas, the baseline prevalence and YCI were as follows: 16.5% and 7.1% for Anaplasma spp.; 81.6% and 100% for Babesia spp.; 0% and 1.3% (only one faint positive) for Dirofilaria immitis; 37.9% and 22.9% for Ehrlichia spp.; 19.5% and 43.8% for Leishmania spp. In Goiana, the baseline prevalence and YCI were as follows: 45.1% and 38.3% for Anaplasma spp.; 79.9% and 96.0% for Babesia spp.; 36.3% and 39.8% for D. immitis; 64.7% and 58.5% for Ehrlichia spp.; 14.7% and 19.6% for Leishmania spp. Anti-Borrelia burgdorferi antibodies were not detected in any of the samples tested herein. The prevalence and YCI of Anaplasma spp., D. immitis and Ehrlichia spp. were significantly higher in Goiana. In contrast, the YCI of Leishmania spp. infection was significantly higher in São Joaquim de Bicas.

Conclusions

We confirmed a high prevalence and YCI of various VBPs among privately-owned dogs in two geographical regions of Brazil. Our data also indicate that the risk of infection varies significantly for individual VBPs and between the regions, which may be related to several factors that are still poorly understood.

Canine vector-borne pathogens from dogs and ticks from Tamil Nadu, India

Canine vector-borne diseases (CVBDs) pose a major health problem in dogs globally, with the potential to cause zoonoses, in particular in developing countries where scientific knowledge on the topic is minimal. Blood samples and ticks were collected from stray dogs in Tamil Nadu, South India to assess the prevalence of CVBD-causing pathogens (Anaplasma spp., Babesia spp., Ehrlichia spp., Hepatozoon spp., filarioids and Leishmania spp.). Of the 230 dogs examined, 229 (99.6%) were infested by ticks (mean intensity, 5.65) with Rhipicephalus sanguineus sensu lato and Rhipicephalus haemaphysaloides being morphologically identified in the 98.3% and 1.7% of the infested dogs, respectively. Overall, the 67.8% (n = 156) of dogs was positive for at least one pathogen with Hepatozoon canis being the most prevalent (37.8%) followed by Anaplasma platys (22.6%), Ehrlichia canis (16.1%) Babesia vogeli (10%), Anaplasma phagocytophilum (0.4%) and Babesia gibsoni (0.4%). Two filarioids (Dirofilaria sp. "hongkongensis" and Brugia malayi, 0.4%) were diagnosed in sampled animals. Co-infection with H. canis and A. platys was the most prevalent (8.3%, P = 0.00001), whilst all animals scored negative for Leishmania spp.. Out of 295 ticks analysed, 215 R. sanguineus s.l. (75.4%) and 8 R. haemaphysaloides (88.9%) were positive for at least one pathogen with H. canis as the predominant species (42.5%), followed by A. platys (33.8%), E. canis (16.9%), B. vogeli (3.8%) and A. phagocytophilum (0.3%). Fifty-six dogs (35.9%) harboured the same pathogen as the respective tick specimens, while 29 dogs (18.6%) had a different pathogen. Thirteen sequence types (STs) were identified for H. canis, with ST2 (49.4%) as the most representative in dogs and ST1 (73.5%) in ticks. Similarly, seven STs were found for Anaplasma spp. (i.e., five for A. platys, one for A. phagocytophilum and one for Anaplasma sp.), with ST2 as the most representative in dogs (70.6%) and ST3 (52.5%) in ticks for A. platys. Only one ST was identified for B. vogeli, B. gibsoni, E. canis, D. sp. "hongkongensis" and B. malayi. Regular surveillance and adoption of adequate treatment and control measures are needed to reduce the risk of disease-causing pathogens in stray dogs and of pathogens with zoonotic potential.

Uncommon Ehrlichia canis infection associated with morulae in neutrophils from naturally infected dogs in Brazil

Ehrlichia and Anaplasma species are the most common tick-borne disease (TBD) pathogens in dogs worldwide. Ehrlichia canis, the aetiological agent of the Canine Monocytic Ehrlichiosis (CME), is known to replicate within the cytoplasm of mononuclear cells into clusters of organisms called morulae. However, detection of morulae in neutrophils is commonly observed in dogs infected by Ehrlichia ewingii or Anaplasma phagocytophilum. We report uncommon clinical cases of canine ehrlichiosis presenting morulae compatible with E. ewingii and A. phagocytophilum in dogs from two distinct regions of Brazil. Eight dogs were admitted to two veterinary teaching hospitals from Brazil, showing clinical or haematological signs suggestive of TBD. Blood or peritoneal fluid was withdrawn for haematological and cytologic analysis. All samples were evaluated by PCR assays for Ehrlichia and Anaplasma using genus-specific primers for dsb, 16S rRNA and groEL genes, followed by sequencing. Samples were also evaluated by nested PCR assays for the 16S rRNA gene of E. ewingii and groEL gene of A. phagocytophilum and Anaplasma platys. Seven dogs revealed thrombocytopenia, six dogs had monocytosis and five presented lymphopenia and anaemia. All dogs showed morulae structures compatible with Ehrlichia spp. in neutrophils and were PCR-positive for the dsb and 16S rRNA gene fragments of Ehrlichia, with sequences showing 100% identity with multiple E. canis sequences deposited in the GenBank™. Sequencing of 16S rRNA and groEL gene fragments from one PCR-positive dog showed 100% identity with A. platys. Overall, our data suggest that in endemic regions for E. canis, that is Brazil, the presence of morulae in neutrophils may indicate infection by this bacterium. Herein, morulae were also found in neutrophils present in the peritoneal fluid of a dog. Also, this is the first report of E. canis and Hepatozoon canis co-infection in neutrophils from naturally infected dogs confirmed by DNA sequencing.

A review on the occurrence of companion vector-borne diseases in pet animals in Latin America

Companion vector-borne diseases (CVBDs) are an important threat for pet life, but may also have an impact on human health, due to their often zoonotic character. The importance and awareness of CVBDs continuously increased during the last years. However, information on their occurrence is often limited in several parts of the world, which are often especially affected. Latin America (LATAM), a region with large biodiversity, is one of these regions, where information on CVBDs for pet owners, veterinarians, medical doctors and health workers is often obsolete, limited or non-existent. In the present review, a comprehensive literature search for CVBDs in companion animals (dogs and cats) was performed for several countries in Central America (Belize, Caribbean Islands, Costa Rica, Cuba, Dominican Republic, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Puerto Rico) as well as in South America (Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, French Guiana, Guyana (British Guyana), Paraguay, Peru, Suriname, Uruguay, Venezuela) regarding the occurrence of the following parasitic and bacterial diseases: babesiosis, heartworm disease, subcutaneous dirofilariosis, hepatozoonosis, leishmaniosis, trypanosomosis, anaplasmosis, bartonellosis, borreliosis, ehrlichiosis, mycoplasmosis and rickettsiosis. An overview on the specific diseases, followed by a short summary on their occurrence per country is given. Additionally, a tabular listing on positive or non-reported occurrence is presented. None of the countries is completely free from CVBDs. The data presented in the review confirm a wide distribution of the CVBDs in focus in LATAM. This wide occurrence and the fact that most of the CVBDs can have a quite severe clinical outcome and their diagnostic as well as therapeutic options in the region are often difficult to access and to afford, demands a strong call for the prevention of pathogen transmission by the use of ectoparasiticidal and anti-feeding products as well as by performing behavioural changes.

Molecular evidence of Anaplasma phagocytophilum and Theileria equi coinfection in horses from Rio de Janeiro, Brazil

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Molecular evidence of coinfection with A. phagocytophilum and T. equi in horses in Brazil was confirmed for the first time by the detection of DNA from both agents.

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EGA should be included in differential diagnosis of tick-borne diseases in horses.

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Different clinical manifestations in horses may be due to coinfection.

The present study aims to determine the frequencies of Theileria equi and Anaplasma phagocytophilum antibodies among horses from the state of Rio de Janeiro, Brazil, and to detect the presence of DNA of these pathogens through molecular methods. A total of 98 serum samples of horses from the municipality of Seropedica were tested by indirect immunofluorescence antibody (IFA) to detect anti-A. phagocytophilum and anti-T. equi IgG antibodies. In addition, quantitative real-time PCR (qPCR) was used to detect these pathogens in the DNA extracted from the whole blood and buffy coat of horses. Bivariate analysis and odds ratio were performed to verify the possible association between positivity and characteristics related to the horses. As evaluated by IFA and qPCR, the frequency of animals that tested positive for T. equi was 89.8% (n = 88/98) and 91.8% (n = 90/98), whereas A. phagocytophilum was 17.4% (n = 17/98) and 1.0% (n = 1/98), respectively. Serological evidence of exposure to A. phagocytophilum and T. equi was observed in 16.3% (n = 16/98) of the horses; however, exposure was confirmed by qPCR in only 1.0% (n = 1/98). No statistical association was found in the bivariate and odds ratio analysis. This is the first study reporting the molecular detection of A. phagocytophilum DNA in horses from the state of Rio de Janeiro, and also the coinfection of A. phagocytophilum and T. equi in a horse from Brazil confirmed by molecular methods. Equine granulocytic anaplasmosis is circulating in Brazilian horses, together with T. equi, and should be included in the differential diagnosis of tick-borne diseases.

First Molecular Survey on Anaplasma phagocytophilum Revealed High Prevalence in Rural Dogs from Khuzestan Province, Iran

BACKGROUND

Anaplasmosis due to Anaplasma phagocytophilum is an important tick-borne zoonotic disease, which affects dogs, horses, cattle and human as well. This study aimed to probe the existence of this organism by means of molecular biology techniques for the first time in rural dogs of Khuzestan province, Southwestern Iran.

METHODS

During Sep 2014 to Apr 2015 blood samples of 103 apparently healthy rural dogs (60 males) were collected for A. phagocytophilum detection by light microscopical examination of Giemsa stained slides and Nested PCR on a fragment of 16S rRNA gene.

RESULTS

From the examined slides, 11.65% were positive for A. morulae while 57.28% of infection was revealed by Nested PCR method. There was no statistical difference between ages and sexes of dogs and infection in molecular survey of A. phagocytophilum.

CONCLUSION

Molecular prevalence of A. phagocytophilum was noticeably high. It may cause the incidence of disease in human population.

Bovine anaplasmosis and tick-borne pathogens in cattle of the Galapagos Islands

A cross-sectional study was conducted to determine the species of Anaplasma spp. and estimate its prevalence in cattle of the three main cattle-producing Galapagos Islands (Santa Cruz, San Cristóbal and Isabela) using indirect PCR assays, genetic sequencing and ELISA. Ticks were also collected from cattle and scanned for 47 tick-borne pathogens in a 48 × 48 real-time PCR chip. A mixed effects logistic regression was performed to identify potential risk factors explaining Anaplasma infection in cattle. A. phagocytophilum was not detected in any of the tested animals. Genetic sequencing allowed detection of A. platys-like strains in 11 (36.7%) of the 30 Anaplasma spp.-positive samples analysed. A. marginale was widespread in the three islands with a global between-herd prevalence of 100% [89; 100]_{95% CI} and a median within-herd prevalence of 93%. A significant association was found between A. marginale infection and age with higher odds of being positive for adults (OR = 3.3 [1.2; 9.9]_{95% Bootstrap CI} ). All collected ticks were identified as Rhipicephalus microplus. A. marginale, Babesia bigemina, Borrelia theileri and Francisella-like endosymbiont were detected in tick pools. These results show that the Galapagos Islands are endemic for A. marginale.

First Molecular Evidence of Anaplasma phagocytophilum in Rodent Populations of Nanchang, China

In this study, systematic surveillance of rodent populations in Nanchang of China and determination of Anaplasma phagocytophilum infection in rodents were performed. Between 2011 and 2015, 110,084 rodent snap traps were set in 4 counties and in the city center of Nanchang, China. Finally, 942 rodents were captured, with a relative density of 0.86%. The densities varied considerably by geographical area with Anyi being the most rodent-infested County. Frequently captured rodents were sewer rats (Rattus norvegicus), house mice (Mus musculus), and Rattus flavipectus. The Anaplasma genera were investigated by PCR in 19 live rodents trapped by welded cages in Anyi, 6 rodents were assessed as positive based on amplification of 16S rRNA. Sequence analysis revealed 3 variants of A. phagocytophilum in Nanchang. PCR analysis of the gltA (citrate synthase) gene found 1 sample that was positive for A. phagocytophilum infection. The sequence of A. phagocytophilum gltA gene formed a clade with and showed 99% identity to A. phagocytophilum that has been previously described in rodents from South-Eastern China. Taken together, our research indicated that commensal rodents are potential hosts for A. phagocytophilum and controlling the rodent population may facilitate subsequent prevention of human granulocytic anaplasmosis in Nanchang, China, in the future.

Molecular detection of Anaplasmataceae agents in Dasyprocta azarae in northeastern Brazil

Recently, the importance of wild-living rodents for maintenance of pathogens of the family Anaplasmataceae in the environment was investigated. These mammals play a role as reservoirs for these pathogens and act as hosts for the immature stages of tick vectors. The aim of the present study was to investigate the prevalence of Ehrlichia sp. and Anaplasma sp. in 24 specimens of Azara's agouti (Dasyprocta azarae) that had been trapped in the Itapiracó Environmental Reserve, in São Luís, Maranhão, northeastern Brazil, using molecular methods. Four animals (16.7%) were positive for Ehrlichia spp. in nested PCR assays based on the 16S rRNA gene. In a phylogenetic analysis based on the 16S rRNA gene, using the maximum likelihood method and the GTRGAMMA+I evolutionary model, Ehrlichia sp. genotypes detected in Azara's agoutis were found to be closely related to E. canis and to genotypes relating to E. canis that had previously been detected in free-living animals in Brazil. The present work showed the first molecular detection of Ehrlichia sp. in Azara's agoutis in Brazil.

Epidemiology of Spotted Fever Group Rickettsioses and Acute Undifferentiated Febrile Illness in Villeta, Colombia

Etiology of acute undifferentiated febrile syndrome (AUFS) is often unknown, leading to inaccurate diagnosis and treatment. Villeta town has been identified as an endemic area for spotted fever group (SFG) rickettsioses but little is known about possible amplifier hosts and other Rickettsia species different from Rickettsia rickettsii. Besides, few studies have approached other AUFS etiologies in the region. We investigated the role of dengue, leptospirosis, rickettsioses, human anaplasmosis, and Q fever as possible causes of AUFS in patients from Villeta. Sera specimens and ticks from animals as well as ticks from vegetation were studied for the presence of different Rickettsia spp. Among 104 sera from patients with AUFS, 16.4%, 24.0%, and 2.9% patients seroconverted to dengue, Leptospira, and SFG Rickettsia, respectively, with a case of probable coinfection or cross-reaction with Anaplasma phagocytophilum. None of the samples were reactive for Coxiella burnetii. Sera samples from 74 horses, 118 dogs, and 62 bovines were collected and showed 33.8%, 14.4%, and 50.0% of seroprevalence for SFG Rickettsia, respectively. A total of 1,287 ixodid ticks were collected from animals/vegetation and processed in pools for polymerase chain reaction. Among them, 1.7% was positive for Rickettsia genes, and Rickettsia amblyommii, R. rickettsii, and Rickettsia spp. were found. These results confirm the circulation of dengue, different SFG Rickettsia species and the relevance of other etiologies like leptospirosis and human anaplasmosis. Further studies must identify different epidemiological variables to establish proper surveillance and control programs.

The prevalence of Anaplasma platys and a potential novel Anaplasma species exceed that of Ehrlichia canis in asymptomatic dogs and Rhipicephalus sanguineus in Taiwan

Canine anaplasmosis is regarded as an infection by Anaplasma platys rather than zoonotic Anaplasma phagocytophilum in subtropical areas based on the assumption that the common dog tick species is Rhipicephalus sanguineus, which transmits E. canis and presumably A. platys. We investigated asymptomatic dogs and dog ticks from 16 communities in Nantou County, Taiwan to identify common dog tick species and to determine the prevalence of Anaplasma and Ehrlichia spp. Of total 175 canine blood samples and 315 ticks, including 306 R. sanguineus and 9 Haemaphysalis hystricis, 15 dogs and 3 R. sanguineus ticks were positive for E. canis, while 47 dogs and 71 R. sanguineus ticks were positive for A. platys, via nested PCR for 16S rDNA and DNA sequencing of selected positive amplicons. However, among the dogs and ticks that were positive to A. platys 16S rDNA, only 20 dogs and 11 ticks were positive to nested PCR for A. platys groEL gene. These results revealed the importance of searching for novel Anaplasma spp. closely related to A. platys in dogs and ticks. Seropositivity to a commercial immunochromatographic test SNAP 4Dx Anaplasma sp. was not significantly associated with PCR positivity for A. platys but with infestation by ticks carrying A. platys (P<0.05). Accordingly, R. sanguineus may be involved in transmission of A. platys but may not act as a reservoir of E. canis and PCR results for 16S rDNA could be a problematic diagnostic index for A. platys infection.

Assessment of a quantitative 5' nuclease real-time polymerase chain reaction using groEL gene for Ehrlichia and Anaplasma species in rodents in Brazil

New genotypes of Anaplasmataceae agents have been detected in wild carnivores, birds and deer in Brazil. The present work aimed to investigate the presence of Ehrlichia and Anaplasma species in rodents sampled in Brazil. Additionally, a newly designed quantitative 5' nuclease real-time multiplex PCR for Ehrlichia and Anaplasma spp. detection based on groEL gene amplification was designed, showing high specificity and sensitivity (10 groEL fragment copy/μL). Between 2000 and 2011, different rodent species [n=60] were trapped in 5 Brazilian biomes. Among 458 rodent spleen samples, 0.4% (2/458) and 2.4% (11/458) were positive for Ehrlichia and Anaplasma spp., respectively. Of 458 samples, 2.0% (9/458) and 1.1% (5/458) were positive for Anaplasma sp. and Ehrlichia sp., respectively, using conventional 16S rRNA PCR assays. Maximum Likelihood phylogenetic analyse based on a small region of 16S rRNA genes positioned the Anaplasma genotypes in rodents near Anaplasma phagocytophilum or Anaplasma marginale and Anaplasma odocoilei isolates. Ehrlichia genotypes were closely related to E. canis. There was a low occurrence of Anaplasma and Ehrlichia in wild and synanthropic rodents in Brazil, suggesting the circulation of new genotypes of these agents in rodents in the studied areas.

Exposure to vector-borne pathogens in privately owned dogs living in different socioeconomic settings in Brazil

This survey was conducted in four Brazilian cities, from three federative units (Pernambuco, Minas Gerais, and Federal District), representing different socioeconomic settings, to determine the presence of antibodies to or antigens and DNA of selected pathogens in privately owned dogs. From January to April 2015, blood and serum samples were collected and assayed using different tests. In particular, antibodies to Anaplasma spp., Borrelia burgdorferi sensu lato, and Ehrlichia spp., and antigens of Dirofilaria immitis were detected using a rapid enzyme-linked immunosorbent assay, whereas antibodies to Babesia spp. were detected by an immunofluorescence antibody assay. Moreover, the presence of Leishmania DNA in blood samples was assessed by real-time polymerase chain reaction. Overall, 208 (69.3%) out of 300 dogs were positive for at least one tested pathogen (intended here as antibodies, antigen or DNA, as abovementioned), with 139 (66.8%) of them being positive to two or more pathogens. No dog presented antibodies to B. burgdorferi s.l., and D. immitis antigens were detected exclusively in dogs from Pernambuco. Among positive dogs, the most common clinical signs were lymphadenomegaly (45.2%), onychogryphosis (41.3%), dermatitis (34.1%), pale mucous membranes (19.7%), weight loss (14.9%), fever (12.5%), alopecia (11.1%), and lethargy (4.8%). Tick and flea infestations were recorded in 41.7% and 29.3% of the dogs, respectively, with 49 (16.3%) dogs being co-infested by both ticks and fleas. Most of the tick- and flea-infested dogs presented high level of infestation (>10 ticks and >20 fleas). The level of tick infestation varied significantly among federative units, being highest in Minas Gerais (68.0%), followed by Pernambuco (36.0%) and Federal District (21.0%). On the other hand, the level of flea infestation was higher in Pernambuco (50.0%), followed by Minas Gerais (29.0%) and Federal District (9.0%). The number of dog owners reporting the use of ectoparasiticides (on dogs and/or in the environment) varied significantly, ranging from 6.0% in Pernambuco to 60.0% in Federal District. This study reveals disparate results in terms of dog exposure to fleas and ticks in the studied communities, which may be related to factors such as the owners' capability/willingness to afford the use of ectoparasiticides on their dogs and the dog's level of restriction. Further research is needed to establish the relationship between dog owners' socioeconomic situation and the level of exposure to ectoparasites and their transmitted pathogens.

Molecular detection of Anaplasma species in dogs in Colombia

Abstract Anaplasma platys and A. phagocytophilum are tick-borne pathogens that parasitize platelets and neutrophils, respectively, of humans and animals. The former is the etiological agent of canine cyclic thrombocytopenia, while the latter is that of canine granulocytic anaplasmosis. This work involved the detection and identification of Anaplasma species in blood samples from dogs in Colombia, using molecular techniques. Between December 2008 and April 2009, blood samples were drawn from the cephalic vein of 91 dogs in the central-western region of Colombia (cities of Bogota, Villavicencio and Bucaramanga) and stored in tubes containing EDTA. These samples were used in 16S rRNA-Anaplasma spp. nPCR and the preparation of blood smears. One (1.1%) of the 91 sampled dogs showed inclusions suggestive of Anaplasmataceae agents in the cytoplasm of platelets. Based on PCR followed by sequencing and phylogenetic analysis, A. platys and Anaplasma sp. closed related to A. phagocytophilum were detected in two and one dog, respectively. Interestingly, all the samples were negative for specific msp-2-A. phagocytophilum real-time qPCR, suggesting the circulation of an Anaplasma species phylogenetically related to A. phagocytophilum in dogs in the aforementioned region. Hence, Anaplasma spp. circulates among dogs in Colombia, albeit with low frequency. To the best of authors' knowledge, this is the first molecular detection of Anaplasma spp. in dogs in Colombia.

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

Since dogs presenting several vector borne diseases can show none or nonspecific clinical signs depending on the phase of infection, the assessment of the particular agents involved is mandatory. The present study aimed to investigate the presence of Babesia spp., Ehrlichia spp., Anaplasma spp., Hepatozoon spp. and Leishmania spp. in blood samples and ticks, collected from two dogs from Rio Grande do Norte showing suggestive tick-borne disease by using molecular techniques. DNA of E. canis, H. canis and L. infantum were detected in blood samples and R. sanguineus ticks collected from dogs. Among all samples analyzed, two showed the presence of multiple infections with E. canis, H. canis and L. infantum chagasi. Here we highlighted the need for molecular differential diagnosis in dogs showing nonspecific clinical signs.

Ectoparasite Infestations and Canine Infection by Rickettsiae and Ehrlichiae in a Semi-Arid Region of Northeastern Brazil

This study investigated the prevalence of Rickettsia spp. and Ehrlichia canis infection in dogs and their ectoparasites from rural and urban areas of two municipalities, Petrolina and Juazeiro, within a semiarid region (Caatinga biome) of northeastern Brazil, by immunofluorescence assay (IFA) and polymerase chain reaction (PCR). Overall, 12.1% (61/504) and 23.0% (116/504) of canine plasma samples had antibodies reactive to Rickettsia spp. and E. canis. E. canis DNA was detected by PCR in 8.3% (42/504) of canine blood samples, whereas no blood sample was positive for Rickettsia spp. The infection by E. canis was determined by PCR in 4.9% (14/285) Rhipicephalus sanguineus sensu lato (s.l.) ticks and by Rickettsia felis in 1.1% (3/285) and 40.6% (74/182) ticks and fleas, respectively. Multivariate regression analyses revealed that canine seropositivity to Rickettsia spp. was associated statistically with the variables "to reside in Petrolina" and "presence of ectoparasites." Our results indicate that canine infection by E. canis might be endemic in the Caatinga biome as it is in other Brazilian biomes. Although no previous serosurvey for Rickettsia spp. has been conducted on dogs from the Caatinga biome, our values are much lower than the ones reported for rural dogs from other Brazilian biomes. These differences are likely related to the semiarid climate of the aatinga biome, which minimizes the exposure of rural dogs to Amblyomma spp. ticks, the most common vectors of Rickettsia spp. in Brazil. Considering that dogs are excellent sentinels for human exposure to Rickettsia spp., we can infer that the risks of human acquiring tick-borne rickettsiosis in the Caatinga region of the present study are low. The rickettsial infection rates in fleas and ticks were not related to canine seropositivity; i.e., areas with higher Rickettsia infection rates in fleas had the lowest canine seroreactivity to Rickettsia spp.

Molecular detection and identification of Rickettsiales pathogens in dog ticks from Costa Rica

Although vector-borne diseases are globally widespread with considerable impact on animal production and on public health, few reports document their presence in Central America. This study focuses on the detection and molecular identification of species belonging to selected bacterial genera (Ehrlichia, Anaplasma and Rickettsia) in ticks sampled from dogs in Costa Rica by targeting several genes: 16S rRNA/dsb genes for Ehrlichia; 16S rRNA/groEL genes for Anaplasma, and ompA/gltA/groEL genes for Rickettsia. PCR and sequence analyses provides evidences of Ehrlichia canis, Anaplasma platys, and Anaplasma phagocytophilum infection in Rhipicephalus sanguineus s.l ticks, and allow establishing the presence of Rickettsia monacensis in Ixodes boliviensis. Furthermore, the presence of recently discovered Mediterranean A. platys-like strains is reported for the first time in Central America. Results provide new background on geographical distribution of selected tick-transmitted bacterial pathogens in Costa Rica and on their molecular epidemiology, and are pivotal to the development of effective and reliable diagnostic tools in Central America.

Post-mortem hemoparasite detection in free-living Brazilian brown brocket deer (Mazama gouazoubira, Fischer 1814)

Tick-borne infections can result in serious health problems for wild ruminants, and some of these infectious agents can be considered zoonosis. The aim of the present study was the post-mortem detection of hemoparasites in free-living Mazama gouazoubira from Minas Gerais state, Brazil. The deer samples consisted of free-living M. gouazoubira (n = 9) individuals that died after capture. Necropsy examinations of the carcasses were performed to search for macroscopic alterations. Organ samples were collected for subsequent imprint slides, and nested PCR assays were performed to detect hemoparasite species. Imprint slide assays from four deer showed erythrocytes infected with Piroplasmida small trophozoites, and A. marginale corpuscles were observed in erythrocytes from two animals. A. marginale and trophozoite co-infections occurred in two deer. A nested PCR analysis of the organs showed that six of the nine samples were positive for Theileria sp., five were positive for A. phagocytophilum and three were positive for A. marginale, with co-infection occurring in four deer. The results of the present study demonstrate that post-mortem diagnostics using imprint slides and molecular assays are an effective method for detecting hemoparasites in organs.

Alpha proteobacteria of genusAnaplasma(Rickettsiales: Anaplasmataceae): Epidemiology and characteristics ofAnaplasmaspecies related to veterinary and public health importance

TheAnaplasmaspecies are important globally distributed tick-transmitted bacteria of veterinary and public health importance. These pathogens, cause anaplasmosis in domestic and wild animal species including humans.Rhipicephalus, Ixodes, DermacentorandAmblyommagenera of ticks are the important vectors ofAnaplasma.Acute anaplasmosis is usually diagnosed upon blood smear examination followed by antibodies and nucleic acid detection. All age groups are susceptible but prevalence increases with age. Serological cross-reactivity is one of the important issues amongAnaplasmaspecies. They co-exist and concurrent infections occur in animals and ticks in same geographic area. These are closely related bacteria and share various common attributes which should be considered while developing vaccines and diagnostic assays. Movement of susceptible animals from non-endemic to endemic regions is the major risk factor of bovine/ovine anaplasmosis and tick-borne fever. Tetracyclines are currently available drugs for clearance of infection and treatment in humans and animals. Worldwide vaccine is not yet available. Identification, elimination of reservoirs, vector control (chemical and biological), endemic stability, habitat modification, rearing of tick resistant breeds, chemotherapy and tick vaccination are major control measures of animal anaplasmosis. Identification of reservoirs and minimizing the high-risk tick exposure activities are important control strategies for human granulocytic anaplasmosis.

The first clinical and laboratory evidence of co-infection by Anaplasma phagocytophilum and Ehrlichia canis in a Brazilian dog

Information on Anaplasma phagocytophilum in Brazil is very restricted. The aim of this study was to report clinical, parasitological, hematological and molecular evidence of a natural A. phagocytophilum infection of an urban Brazilian dog. The dog was an eight-month-old male French bulldog. Veterinary clinical examinations were performed three times: in April, June and December 2013. Biochemical and hematological analyses were performed during all examinations, and blood samples were collected for parasitological surveys in June and December. Morulae were present within neutrophils in blood smears from June. Both samples were PCR positive for A. phagocytophilum and Ehrlichia spp. Phylogenetic analysis revealed that the phylogenetic topology placed samples from this study in close proximity to other A. phagocytophilum isolates. Ehrlichia isolates from this dog were 100% identical to E. canis isolates, thus E. canis and A. phagocytophilum co-infection was diagnosed in this dog. Lethargy and skin lesions were the clinical signs observed in this dog. Abnormal hematological parameters, among those, severe thrombocytopenia, were observed in all three occasions. This finding highlights the growing importance of A. phagocytophilum in South America.