Temperature effects on the non-parasitic phase of Amblyomma parvum (Acari: Ixodidae)

The tick Amblyomma parvum has a wide distribution in the Central and South America. Therefore, throughout its distribution range, populations of this tick are exposed to different abiotic factors (e.g., Temperature and humidity). Here, we assess the effect of five temperatures, 18°C, 21°C, 24°C, 27°C, 32°C and 80 ± 10% RH on non-parasitic phases of A. parvum under controlled conditions of laboratory. Our results show that temperature affects all parameters of the non-parasitic phases of A. parvum. Mean periods of premolt and molting of immatures, and mean periods of pre-oviposition, oviposition and incubation of females decreases as temperature increases from 18 °C to at 32 °C. Conversely, the molting success of larvae increased from 18 °C to 32 °C but the percentages were statistically non-significant under 21°C, 24°C and 27°C. The molting success of nymphs was higher than 95% under all temperatures. Mean percentages of egg mass and EPE increases as temperature increase from 18 °C to 27°C, then both decrease at 32 °C. The mean percentage of egg hatching was higher than 90% from 21 to 32 °C. The total non-parasitic phase of A. parvum was completed in an average of 223.4, 150.9, 114.7, 90.2 and 69.0 days, respectively, under temperatures of 18°C, 21°C, 24°C, 27°C and 32°C. The effect of five temperatures studied in this experiment suggest that populations of A.parvum can exhibit different biological and ecological behaviors throughout its distribution range, as expected to occur in ticks with wide range distribution.

Ectoparasites of Didelphis virginiana From Yucatan, Mexico

A faunal study is presented to determine the species of ectoparasites found in the opossum Didelphis virginiana (Kerr) (Marsupialia: Didelphidae). For this, Tomahawk traps were placed in the peridomiciles of a rural town in Yucatán, to capture individuals of this marsupial and proceed to the collection of their ectoparasites. A total of 3,023 arthropods were collected from 145 opossums. The most frequent ectoparasites were the acarines Ornithodoros (Alectorobius) nr. talaje (64.8%) (Argasidae); Ornithonyssus wernecki Fonseca (53.8%) (Macronyssidae) and Didelphilicus serrifer Fain (25.5%) (Atopomelidae); the ticks Amblyomma parvum Aragão (8.3%) and A. mixtum Koch (10.3%) (Ixodidae); and the fleas Ctenocephalides felis (Bouché) (20.7%) and Pulex simulans Baker (8.3%) (Pulicidae). It is concluded that the ectoparasite fauna of this marsupial is mainly composed of euryxenous organisms, which have been documented as vectors of diseases caused by rickettsial bacteria. Since D. virginiana is widely adapted to the peridomiciliary environment in the region, this study allows recognizing those that represent a potential risk for the transmission of vector-borne zoonotic diseases.

Anaplasmataceae agents among wild mammals and ectoparasites in Brazil

SUMMARYAnaplasmataceae agents comprise obligate intracellular bacteria that can cause disease in humans and animals. Between August 2013 and March 2015, 31Nasua nasua(coati), 78Cerdocyon thous(crab-eating fox), sevenLeopardus pardalis(ocelot), 110 wild rodents, 30 marsupials, and 42 dogs were sampled in the Pantanal wetland, Brazil. In addition, ectoparasites found parasitizing the animals were collected and identified. The present work aimed to investigate the occurrence of Anaplasmataceae agents in wild mammals, domestic dogs and ectoparasites, by molecular and serological techniques. Overall, 14 (17·9%)C. thous, seven (16·6%) dogs and one (3·2%)N. nasuawere seroreactive toEhrlichia canis. Nine dogs, twoC. thous,oneN. nasua, eight wild rodents, five marsupials, eightAmblyomma sculptum,fourAmblyomma parvum,13A. sculptumnymphal pools, twoAmblyommalarvae pools and onePolygenis (Polygenis) bohlsi bohlsiflea pool were positive forEhrlichiaspp. closely related toE. canis. SevenN. nasua, two dogs, oneC. thous,oneL. pardalis, four wild rodents, three marsupials, 15A. sculptum, twoAmblyomma ovale,twoA. parvumand oneAmblyommaspp. larval pools were positive forAnaplasmaspp. closely related toA. phagocytophilumorA. bovis. The present study provided evidence that wild animals from Brazilian Pantanal are exposed to Anaplasmataceae agents.

Infestação por carrapatos Argasidae e Ixodidae em pequenos mamíferos silvestres da Estação Experimental Rafael Fernandes, Mossoró/RN

RESUMO: Poucos estudos avaliaram a diversidade de ectoparasitos e a associação deles com seus hospedeiros que ocorrem no bioma Caatinga, Nordeste do Brasil. Considerando-se essa falta de conhecimento, este estudo objetivou identificar e determinar a ocorrência de carrapatos coletados de pequenos mamíferos da Estação Experimental Rafael Fernandes, no Rio Grande do Norte, Brasil. De janeiro de 2014 a fevereiro de 2015 foram capturados 52 marsupiais (38 Gracilinanus agilis e 14 Monodelphis domestica) e 10 roedores (5 Wiedomys sp., 4 Thrichomys sp. e 1 Rattus norvegicus). Foram identificados os carrapatos Amblyomma auricularium, Amblyomma parvum, Amblyomma sp., Ornithodoros mimon e Ornithodoros sp., empregando estudo morfológico, chaves taxonômicas e sequenciamento parcial do gene mitocondrial 16S rDNA de carrapatos. Todas as associações carrapato-hospedeiro encontradas neste estudo são relatadas pela primeira vez no Rio Grande do Norte e constituem novos dados ecológicos aplicáveis aos ectoparasitos de pequenos mamíferos no nordeste do Brasil.

Rickettsia amblyommii associado a roedores e marsupiais nativos da Estação Experimental Rafael Fernandes da UFERSA, Rio Grande do Norte

RESUMO: O presente estudo teve como objetivo registrar a ocorrência de Rickettsia sp. em roedores e marsupiais nativos da Estação Experimental Rafael Fernandes da UFERSA, Mossoró/RN. O trabalho consistiu em uma pesquisa de campo, com roedores e marsupiais silvestres, com os dados expressos em frequência simples e porcentagem através do programa estatístico IBM SPSS (Armonk, NY: IBM Corp.), versão 22.0. Coletaram-se amostras de plasma sanguíneo de marsupiais (36) e de roedores (5). Destes, 64 continham Amblyomma auricularium, 7 Amblyomma parvum e 12 Amblyomma sp. As amostras de plasma sanguíneo foram analisadas através da técnica de Reação de Imunofluorescência Indireta. Exemplares de A. auricularium e a A. parvum foram macerados e submetidos a Técnica de Reação em Cadeia da Polimerase. Das amostras de plasma testadas, 17,60% apresentaram soropositividade para Rickettsia amblyommii. Oito exemplares de A. auricularium estavam positivos para R. amblyommii na análise de fragmentos dos genes gltA (350 bp) e ompA (587 pb), com 100% de similaridade com Candidatus R. amblyommii estirpe Bahia e AaPE, correspondendo a uma baixa circulação do agente dentre os vetores e hospedeiros. Esta pesquisa registra pela primeira vez a ocorrência de R. amblyommii em marsupiais Gracilinanus agilis e Monodelphis domestica pertencentes a Família Didelphidae, e roedores das Famílias Echimyidae e Cricetidae, cujas espécies foram Thrichomys sp. e Wiedomys sp., respectivamente, em Mossoró, estado do Rio Grande do Norte.