Resumen Se informa un caso autóctono de rickettsiosis por Rickettsia parkeri, ocurrido en junio del 2018 en la zona selvática del Parque Provincial Urugua-í, Misiones, Argentina, región sin registros previos de esta enfermedad en humanos. Se describen los aspectos epidemiológicos, ecológicos, clínicos y de laboratorio necesarios para el diagnóstico oportuno y el tratamiento adecuado. Se resalta el hecho de considerar a las rickettsiosis como diagnóstico diferencial ante un paciente con síndrome febril agudo exantemático; el antecedente epidemiológico de exposición al vector característico de la región, garrapatas del género Amblyomma, es un elemento fundamental.

Abstract We report an autochthonous case of Rickettsia parkeri rickettsiosis occurred in June 2018 in a forested area of the Urugua-í Provincial Park, Misiones, Argentina. No previous records of this disease in humans have been previously reported in this region. The epidemiological, ecological, clinical, and laboratory features required for a proper diagnosis and adequate treatment are described here. The fact of considering rickettsiosis as a differential diagnosis in a patient with exanthematic acute febrile syndrome is highlighted, being the epidemiological history of exposure to the vector (ticks of the genus Amblyomma) an essential element.

The present study aimed to determine the presence of ticks in the Ecological Reserve Ciudad Universitaria -Costanera Norte, protected natural area of the CABA, close to a highly trafficked urban area. In the period August 2017 to July 2018, 829 Ixodes auritulus (larvae, nymphs, adults) and a nymph of Rhipicephalus sanguineus sensu lato were collected from the vegetation in three sample sites on a monthly interval.

El presente estudio se realizó con el objetivo de determinar la presencia de garrapatas en la Reserva Ecológica Ciudad Universitaria -Costanera Norte, área natural protegida de la CABA, lindante con un área urbana con alto tránsito de personas. Entre agosto de 2017 y julio de 2018 se recolectaron 829 Ixodes auritulus (larvas, ninfas, adultos) y una ninfa de Rhipicephalus sanguineus sensu lato de la vegetación en tres puntos muestreados mensualmente.

RESUMO: A ehrlichiose monocítica canina (CME) é uma doença infecciosa transmitida pelo carrapato Rhipicephalus sanguineus sensu lato com distribuição mundial causada por Ehrlichia canis, que pode produzir uma doença grave se não foi diagnosticada e tratada precocemente. A confirmação da doença é feita diretamente pela detecção do DNA fazendo a reação em cadeia da polimerase (PCR) ou indiretamente por métodos sorológicos. O objetivo deste estudo foi comparar o método sorológico baseado na imunocromatografia e a técnica de PCR para o diagnóstico de E. canis em cães suspeitos da Cidade de Buenos Aires e da região sul da Grande Buenos Aires. As amostras de sangue de 20 cães clinicamente saudáveis (Grupo Controle) e de 80 cães com suspeita clínica de CME (Grupo 1-4) foram avaliadas em paralelo. O diagnóstico serológico foi feito pelo teste imunocromatográfico SPEED® EHRLI (BVT, França). Para a detecção molecular, foi utilizada uma PCR de triagem para amplificar um fragmento de 345 pb do gene que codifica a subunidade 16S do rRNA da família Anaplasmataceae. As amostras positivas depois foram processadas pela PCR aninhada específica para E. canis. No Grupo Controle, a presença de E. canis não foi detectada por PCR ou anticorpos específicos com o teste imunocromatográfico. No grupo em que a sorologia foi solicitada inicialmente (1 e 2), a concordância entre os testes foi baixo (kappa: 0,200) enquanto que no grupo onde o teste inicialmente solicitado foi a PCR, a concordância entre os testes era adequado (kappa: 0,650). A concordância entre os testes avaliados na população total estudada foi moderada (kappa: 0,496). Em conclusão, os resultados do nosso estudo sugerem que o uso de testes serológicos rápidos inicialmente, juntamente com a confirmação subsequente por PCR, permitirá melhorar o diagnóstico de CME.

ABSTRACT: Canine monocytic ehrlichiosis (CME) is an infectious disease caused by the bacterium Ehrlichia canis and transmitted by Rhipicephalus sanguineus sensu lato, a tick with worldwide distribution. When not diagnosed and treated early, disease can be severe. Currently, the disease is confirmed by serological or molecular assays. The objective of this study was to compare a serological assay based on immunochromatography (SPEED® EHRLI immunochromatographic test; BVT, France) and a molecular assay (a screening PCR followed by a nested PCR specific for E. canis) for the diagnosis of E. canis in suspected dogs from Buenos Aires city and southern Greater Buenos Aires, Argentina. Blood samples from 20 clinically healthy dogs (Control Group) and from 80 sick dogs suspected of having CME (Groups 1 to 4) were tested in parallel. Neither the immunochromatographic test nor the PCR assay was able to detect the presence of E. canis in the Control Group. In the group which had been previously tested by serology, the agreement between the tests was low (kappa: 0.200), whereas in the group which had been previously tested by PCR, the concordance between the tests was adequate (kappa: 0.650). The concordance between the tests evaluated in the total population studied was moderate (kappa: 0.496). The results of our study suggest that the use of rapid serological tests as a first approach, together with subsequent confirmation by PCR, will improve the diagnosis of CME.

INTRODUCTION: Ticks (Acari, Ixodida) are arthropod vectors of great diversity of viral, bacterial and protozoan pathogens, many of which are zoonotic and emerging. In Argentina, there are numerous hard tick species (Ixodidae family) which also parasitize humans. Protected urban areas are natural ecosystems located within or near large urban centers. The Costanera Sur Ecological Reserve (RECS) of Buenos Aires city shows a circulation of wild species that have no presence in other areas of the city. There are potential hosts and vectors. OBJECTIVES: A quantitative cross sectional study was carried to detect the species of ticks present in the RECS of Buenos Aires city. METHODS: A quantitative cross - sectional study was carried out by sampling to collect ticks from vegetation and hosts (rodents and dogs). RESULTS: In total, 1090 ticks were collected from the vegetation (454 of the species Amblyomma aureolatum, 635 Ixodes auritulus and 1 Amblyomma triste) and 67 from dogs (64 A. aureolatum, 2 Rhipicephalus sanguineus sensu lato and 1 A. triste). No ticks were detected in 200 examined rodents. CONCLUSIONS: Ticks species detected in this study are important for public health, because they are parasites of humans (A. aureolatum, A. triste and R. sanguineus s. l.) and participate in the cycle and transmission of different zoonotic pathogens in different regions of the world, including Argentina.

INTRODUCCIÓN: Las garrapatas (Acari, Ixodida) son artrópodos vectores de gran diversidad de patógenos virales, bacterianos y protozoarios, muchos de los cuales son zoonóticos y emergentes. En Argentina se encuentran numerosas especies de garrapatas duras (familia Ixodidae) que también parasitan al hombre. Las áreas urbanas protegidas son ecosistemas naturales que están dentro de grandes urbes o limitan con ellas. En la Reserva Ecológica Costanera Sur (RECS) de la Ciudad Autónoma de Buenos Aires (CABA) circulan especies silvestres que no tienen presencia en otras áreas de la ciudad, con potenciales hospedadores y vectores. OBJETIVOS: Determinar las especies de garrapatas presentes en la RECS (CABA). MÉTODOS: Se realizó un estudio cuantitativo descriptivo transversal mediante muestreos para colectar garrapatas de vegetación y de hospedadores como perros y distintas especies de roedores. RESULTADOS: En total se recolectaron 1090 garrapatas de la vegetación (454 de la especie Amblyomma aureolatum, 635 Ixodes auritulus y 1 Amblyomma triste) y 67 de los perros (64 A. aureolatum, 2 Rhipicephalus sanguineus sensu lato y 1 A. triste). No se detectaron garrapatas en 200 roedores revisados. CONCLUSIONES: Las especies de garrapatas detectadas en este estudio tienen importancia en salud pública, tanto porque parasitan a humanos (A. aureolatum, A. triste y R. sanguineus s. l.) como porque participan en el ciclo y transmisión de distintos patógenos zoonóticos en distintas regiones del mundo, incluso Argentina.

Abstract: The tropical fowl mite (Ornithonyssus bursa) is a common parasite of domestic and wild birds in tropical and subtropical regions. This mite can cause irritation, severe dermatitis and anemia. The European starling (Sturnus vulgaris) is an invasive bird in Argentina. Both O. bursa and S. vulgaris have high reproductive rates with implications for public health. The goals of our study were to report the occurrence of this mite parasitizing the starlings, and test for the presence of bacteria that could be potentially associated with the mites. The study was conducted in Estación de Cría de Animales Silvestres (Buenos Aires, Argentina). Mites were collected from starlings and stored in 96% ethanol, and prepare for their identification under an optic microscope. Molecular studies were conducted in order to examine the presence of bacteria. All mites were identified as O. bursa. We detected for the first time Wolbachia sp., associated with the genus Ornithonyssus. In contrast, mites were negative for species of Rickettsia, Bartonella and Borrelia. In addition to the damage that the starlings produce as an invasive species in central Argentina, herein we report the association of these birds with O. bursa, favoring the dispersal of the mites and their colonization to other birds.

Resumen: Ornithonyssus bursa es un parásito común en aves domésticas y silvestres de regiones tropicales y subtropicales que puede causar irritación, dermatitis severa y anemia. El estornino pinto (Sturnus vulgaris) es un ave invasora en Argentina. Tanto O. bursa como S. vulgaris tienen altas tasas de reproducción con implicaciones en salud pública. Los objetivos del estudio fueron reportar la presencia de este ácaro parasitando a los estorninos y comprobar la potencial asociación de bacterias a los ácaros. El estudio se realizó en la Estación de Cría de Animales Silvestres (Buenos Aires, Argentina). Los ácaros se obtuvieron de estorninos, se almacenaron en etanol 96% y se prepararon para su identificación al microscopio óptico. Se realizaron estudios moleculares con el fin de examinar la presencia de bacterias. Todos los ácaros se identificaron como O. bursa. Se detectó por primera vez la presencia de Wolbachia sp. asociada con el género Ornithonyssus. En contraste, los resultados fueron negativos para las especies de Rickettsia, Bartonella y Borrelia. Además del daño que producen los estorninos como una especie invasora en el centro de Argentina, se presenta la asociación de estas aves con O. bursa, lo que favorece la dispersión de los ácaros y su colonización hacia otras aves.

During March 2013 a population of eared doves (Zenaida auriculata) was established in the center of City of Buenos Aires. Considering the role of these birds as host competent for Saint Louis encephalitis virus (SLEV), a CDC light trap was put in place to perform entomologic surveillance. During this month 5 pools of mosquitoes (n = 48) were collected and taxonomically determined. Three of them were classified as Culex pipiens (n = 10) and the other two were Culex spp. (n = 38). In this case, the mosquitoes species could not be determined due to that individuals were damaged. One of the Culex spp. pool was found to be positive for Saint Louis encephalitis virus by molecular techniques. This was then sequenced and classified as genotype III.

Durante el mes de marzo de 2013 una población de palomas torcazas (Zenaida auriculata) se instaló en una zona céntrica de la ciudad de Buenos Aires. Conociendo el rol que poseen estas aves como hospedadores competentes del virus de la encefalitis de Saint Louis (SLEV), fue colocada en el lugar una trampa de luz tipo CDC, a fin de realizar una vigilancia entomológica. Durante ese mes,fueron capturados 5 grupos de mosquitos (n = 48), 3 correspondieron a la especie Culex pipiens (n = 10) y 2 a Culex spp.(n = 38), no pudiéndose determinar en estos últimos con precisión la especie por encontrarse dañados. En un grupo de mosquitos Culex spp. se detectó el SLEV por técnicas moleculares. Posteriormente fue secuenciado y clasificado como perteneciente al genotipo III.

Background: Rickettsioses, ehrlichioses and anaplasmoses are caused by Gram negative obligate intracellular bacteria and transmitted mainly by arthropods. Aim: To detect and perform the molecular characterization of these pathogens in ticks and domestic dogs in Bahia Blanca City (Buenos Aires, Argentina). Methods: Fifty six blood samples from dogs and 82 ticks (75 Rhipicephalus sanguineus and 7 Amblyomma tigrinum) were studied. The samples were analyzed by PCR for Rickettsia (intergenic space 23S-5S rRNA), Ehrlichia/Anaplasma (16S rRNA), and Anaplasma platys (16S rRNA). Results: 12% of R. sanguineus resulted positive for Rickettsia, identified by sequencing as Rickettsia massiliae; and 37.5% of the canine blood samples analyzed were positive for A. platys. Molecular characterization was also performed by amplification of the fragment of the citrate synthase gene (gltA) (Rickettsia genus) and the groESL gene (A. platys). Phylogenetic trees were constructed using the neighbor-joining method. These trees revealed that sequences obtained are similar to those from other geographical regions. Conclusion: The results indicate the presence of R. massiliae in R. sanguineus ticks for the second time in an urban area of South America and A. platys infection in dogs, being the southernmost region of Argentina where it has been notified.

Introducción: Las rickettsiosis, ehrlichiosis y anaplasmosis son causadas por bacterias gramnegativas, intracelulares obligadas y transmitidas principalmente por artrópodos. Objetivo: Detectar y caracterizar molecularmente estos patógenos en garrapatas y caninos domésticos del municipio de Bahía Blanca (provincia de Buenos Aires, Argentina). Material y Métodos: Se estudiaron 56 muestras sanguíneas de caninos, 75 garrapatas Rhipicephalus sanguineus y 7 Amblyomma tigrinum. Las muestras fueron analizadas por RPC para Rickettsia (espacio intergénico 23S-5S ARNr), Ehrlichia y Anaplasma (16S ARNr), y Anaplasma platys (16S ARNr). Resultados: Se detectó positividad a Rickettsia en 12% de R. sanguineus, identificándose por secuenciación a Rickettsia massiliae. Las muestras sanguíneas de los caninos resultaron en 37,5% positivas a A. platys. También se caracterizaron molecularmente por la amplificación del fragmento del gen citrato sintasa (gltA) (género Rickettsia) y del gen groESL (A. platys). Se construyeron árboles filogenéticos utilizando el método del vecino más cercano (neighbor-joining) revelando que las secuencias obtenidas son similares a las de otras regiones geográficas. Conclusión: Los resultados indican la presencia de R. massiliae en garrapatas R. sanguineus en una segunda zona urbana de Sudamérica y la infección por A. platys en caninos, siendo la región más austral de Argentina donde ha sido notificada.

Neorickettsia risticii is the causative agent of Potomac Horse Fever, a severe febrile disease affecting horses, transmitted by trematodes species with a complex life cycle. A total of 30 insectivorous bats (Brazilian free-tailed bat Tadarida brasiliensis) were analyzed by PCR for presence of genus Anaplasma, Ehrlichia, Neorickettsia and Rickettsia. Three samples showed positive reactions for genus Anaplasma, Ehrlichia and Neorickettsia, and the sequences were 99.67% identical to Neorickettsia risticii. The role of bats in the life cycle of N. risticii has yet to be elucidated; however bats may be reservoirs for this bacterium. To our knowledge, this is the first evidence of N. risticii in Argentina.

Specimens of the hard tick Amblyomma triste were found infected with Rickettsia parkeri in an area of Argentina (General Lavalle, Buenos Aires Province) where cases of human illness attributed to this microorganism have been reported. Molecular detection of R. parkeri was based on polymerase chain reactions that amplify a ca. 400-bp fragment of the 23S-5S intergenic spacer and a ca. 500-bp fragment of the gene encoding a 190-kDa outer membrane protein. Three (6.97%) of 43 A. triste ticks were determined to be positive for R. parkeri. These results provide strong evidence that A. triste is the vector of R. parkeri in the study area. The findings of this work have epidemiological relevance because human parasitism by A. triste ticks has been frequently recorded in some riparian areas of Argentina and Uruguay and new cases of R. parkeri rickettsiosis might arise in the South American localities where humans are exposed to the bites of this tick species.