A new tick Kunitz type inhibitor, Amblyomin-X, induces tumor cell death by modulating genes related to the cell cycle and targeting the ubiquitin-proteasome system

The aim of this study was to evaluate the anti-tumor activity of Amblyomin-X, a serine protease Kunitz-type inhibitor. Amblyomin-X induced tumor mass regression and decreased number of metastatic events in a B16F10 murine melanoma model. Alterations on expression of several genes related to cell cycle were observed when two tumor cell lines were treated with Amblyomin-X. PSMB2, which encodes a proteasome subunit, was differentially expressed, in agreement to inhibition of proteasomal activity in both cell lines. In conclusion, our results indicate that Amblyomin-X selectively acts on tumor cells by inducing apoptotic cell death, possibly by targeting the ubiquitin-proteasome system. (C) 2010 Elsevier Ltd. All rights reserved.

Diversidade e potencial zoonótico de parasitos de Didelphis albiventris Lund, 1841 (Marsupialia: Didelphidae)

Didelphis albiventris, gambá-de-orelha-branca, é um marsupial de hábitos crepusculares e noturnos que se alimenta de frutos, insetos, pequenos répteis e anfíbios, filhotes de aves e pequenos mamíferos. Com a destruição de seu “habitat” natural devido às queimadas e desmatamentos, esses animais têm-se aproximado, cada vez mais, das regiões peridomiciliar e domiciliar, onde procuram abrigo e alimentos. Com o objetivo de conhecer a diversidade de parasitos de D. albiventris e relatar os que apresentam potencial zoonótico, foram examinados 30 exemplares desta espécie, através de necropsia, para coleta de ectoparasitos da superfície externa do corpo e helmintos dos órgãos e conteúdos estomacal e intestinal. Os sifonápteros foram removidos da superfície externa dos animais, conservados em álcool etílico a 70°GL, clarificados em líquido de Nesbitt, desidratados em etanol, diafanizados em creosoto de Faya e montados em lâminas com bálsamo do Canadá para identificação. Os carrapatos foram removidos da superfície externa dos animais, conservados em álcool etílico a 70°GL e identificados ao estereomicroscópio, segundo chaves específicas de Aragão & Fonseca (1961) e Guimarães et al (2001). Os helmintos foram recolhidos com auxílio de estiletes e pinças, clarificados em lactofenol e montados entre lâminas e lamínulas com bálsamo do Canadá para identificação ao microscópio. Do total de animais examinados, 70% estavam infestados com pulgas das espécies Polygenis (Neopolygenis) atopus, Polygenis (Polygenis) rimatus, Polygenis (Polygenis) roberti roberti, Polygenis (Polygenis) sp., Craneopsylla minerva minerva e Ctenocephalides felis felis, todas essas registradas pela primeira vez sobre D. albiventris e, exceto C. felis felis, são também registradas pela primeira vez no estado do Rio Grande do Sul. Carrapatos foram encontrados em 43,33% dos animais examinados, representados pelas espécies Ixodes loricatus, Amblyomma aureolatum e Amblyomma sp, sendo A. aureolatum registrado pela primeira vez parasitando D. albiventris no Brasil. Os helmintos encontrados foram: Filo Nematoda - Capillaria spp. (esôfago, traquéia, faringe e pulmão), Didelphostrongylus hayesi (pulmão), Turgida turgida (estômago), Gnathostoma sp. (estômago e fígado), Travassostrongylus orloffi, Viannaia hamata e Trichuris minuta no intestino delgado e Trichuris didelphis, Cruzia tentaculata e Aspidodera raillieti no intestino grosso; Classe Trematoda – Echinostoma revolutum, Plagiorchis didelphidis, Rhopalias coronatus, R. baculifer, Brachylaema migrans e Didelphodiplostomum variabile, todos no intestino delgado; Classe Cestoda – exemplares da família Diphyllobotriidae, no intestino delgado; e Filo Acanthocephala – Hamanniella microcephala e Centrorhynchus sp., ambos no intestino delgado. Dos helmintos encontrados, os que apresentam potencial zoonótico segundo a literatura são T. turgida, Gnathostoma sp., Capillaria spp., B. migrans, E. revolutum e Família Diphyllobotriidae. Além disso, os sifonápteros e ixodídeos encontrados são potenciais vetores de patógenos que infectam humanos. D. albiventris, portanto, apresenta grande diversidade parasitária, incluindo espécies que podem potencialmente atingir o homem, alertando para a importância destes marsupiais na disseminação de doenças entre animais e humanos.

Ecological aspects of the free-living ticks (Acari: Ixodidae) on animal trails within Atlantic rainforest in south-eastern Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Factors associated to Theileria equi in equids of two microregions from Rio de Janeiro, Brazil

Amostras de soro de 714 equídeos das microrregiões de Itaguaí e Serrana, Rio de Janeiro, Brasil, foram submetidas ao teste de imunofluorescência indireta (título 1:80) para Theileria equi. A prevalência entre as microrregiões e os fatores associados à soropositividade foram avaliados e a razão de prevalência (RP) calculada. A prevalência geral para T. equi foi de 81,09% (n = 579), com maior prevalência (p < 0,05) para microrregião de Itaguaí (85,43%), quando comparado a Serrana (76,92%). A região, altitude, nível da propriedade e origem dos equídeos foram associados (p < 0,05) com a soropositividade para T. equi. Equídeos criados na microrregião de Itaguaí (RP = 1,11; p = 0,003) e em altitudes abaixo de 500 m (RP = 1.10; p = 0,014) apresentaram maior chance de se tornarem soropositivos para T. equi. Além disso, quando são criados em propriedades de nível ruim (RP = 1,13; p = 0,018) e nascidos na propriedade (RP = 1,10; p = 0,008) apresentaram mais chance de terem contato com T. equi. As principais espécies de carrapatos encontradas parasitando os equídeos foram Amblyomma cajennense e Dermacentor (Anocentor) nitens. As microrregiões estudadas são endêmicas para theileriose equina e de estabilidade enzoótica para T. equi. Apenas os fatores relacionados à área de coleta das amostras de soro influenciaram a soropositividade dos equídeos para T. equi naquela região.

Brazilian spotted fever: A reemergent zoonosis

Brazilian spotted fever is caused by the bacterium Rickettsia rickettsii, which is the most pathogenic species of the spotted-fever rickettsiae group and is transmitted by the bite of infected ticks. Amblyomma cajennense is the most important tick species involved in the cycle of this zoonosis in Brazil as it presents low host specificity, great number of natural reservoirs and wide geographic distribution. It was first described in the state of São Paulo in 1929 and later in Rio de Janeiro, Minas Gerais and Bahia. The number of cases decreased in the 1940's with the development of new plague control techniques and antibiotics. In the last decades, the number of new cases has increased. The current review aimed at reporting some of the epidemiological and public health aspects of this reemergent disease with new foci, mainly in the southeastern region of Brazil.

Diversity of ectoparasites in sheep flocks in São Paulo, Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of São Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the 'Associação Paulista de Criadores de Ovinos' (ASPACO; São Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.

Hepatozoon canis infection associated with dog ticks of rural areas of Rio de Janeiro State, Brazil

Hepatozoon canis is a tick-borne protozoan that infects dogs and has been reported throughout the world. Manifestation of H. canis infection varies from being sub-clinical in apparently healthy dogs to severe illness. The main vector of the infection is the dog tick, Rhipicephalus sanguineus although other species may also transmit this agent. H. canis has been reported previously in Brazil, but mostly as an occasional finding during laboratory exams and always associated with other diseases. The prevalence of H. canis in dogs of rural areas of Brazil has been little studied. For this study, 250 dogs from seven counties of Rio de Janeiro state were examined. All the dogs were from rural areas, near forest. of the dogs examined, 26 dogs were from Seropedica, 82 from Itaguai, 41 from Paracambi, 26 from Mangaratiba, 32 from Barra do Pirai, 32 from Pirai and 11 from Miguel Pereira. Blood smears from the peripheral blood of the ear were taken and ticks found on the dogs were collected for identification in the laboratory. Using blood smear evaluation, H. canis was identified in 39.2% of the animals examined. Other hemoparasites identified were Babesia canis (5.2%) and Ehrlichia canis (4.8%). Four tick species were found parasitizing the dogs: Amblyomma cajennense (23.6%), R. sanguineus (12.4%), Amblyomma aureolatum (2.8%) and Amblyomma ovale (2.0%). There was a positive correlation between the presence of A. cajennense and H. canis infection. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Babesia spp. infection in dogs from rural areas of São Paulo State, Brazil

The status of Babesia spp. infection in dogs from rural areas of São Paulo State, Brazil was Studied. For this, l 50 animals were examined by blood smears and by PCR; the presence of tick infestation was also investigated. By the blood smear examination, 3 animals (2%) were detected positive and by PCR for Babesia spp. 12 (8%) were positive, with bands Visualized in 450 bp. Rhipicephalus sanguineus or Amblyomma spp. were found on 36 (24%) of the 150 dogs. Amblyomma species found were A. cajennense (9/36-25%) and A. ovale (9/36-25%). It was not possible to correlate the presence of R. sanguineus and the infection with Babesia spp. The sequencing of four positive samples demonstrated close identity with B. canis vogeli already characterized in Brazil.

Caracterização da população de ectoparasitos em cães de núcleos de expansão urbana de Juiz de Fora, Minas Gerais, Brasil

No presente trabalho caracterizou-se a população de ectoparasitos em cães de núcleo de expansão urbana de Juiz de Fora, MG. As coletas foram realizadas de julho a setembro de 2003, examinando-se 101 cães SRD (sem raça definida). Os ectoparasitos foram coletados através de inspeção visual e tátil dos animais e acondicionados em frascos com etanol 70°GL e identificados sob estereoscopia. Espécimes foram clarificados e montados para análise em microscopia fotônica. Dentre os sifonápteros, Ctenocephalides felis foi mais prevalente (64,35%) com intensidade média de 6,12 ± 5,37 sifonápteros/cão, seguido por Rhopalopsyllus lutzi (3,96%), híbrida C. felis X C. canis (1,98%), Tunga penetrans (1,98%). Aúnica espécie de fitiráptero encontrada foi Trichodectes canis (7,92%) com 1,3 ± 0,51 fitiráptero/cão. Dentre os ixodídeos, Rhipicephalus sanguineus foi a espécie mais prevalente (49,50%) com intensidade média de 6,44 ± 10,2 ixodídeos/ cão, seguido por Amblyomma cajennense (3,96%), Boophilus microplus (2,97%), A. ovale (1%) e A. aureolatum (1%). As ninfas de ixodídeos foram separadas em ninfas de Amblyomminae (58,41%) com 10,11 ± 10,09 ninfas/cão e ninfas Rhipicephalinae (24,75%) com 2,64 ± 3,25 ninfas/cão. em 3,96 % dos cães foram encontradas larvas de ixodídeo.

Soroprevalência de Borrelia burgdorferi latu sensu associada à presença de carrapatos em cães de áreas rurais do Estado do Rio de Janeiro, Brasil

Pesquisou-se a presença de anticorpos contra Borrelia burgdorferi latu sensu em cães de áreas rurais de sete municípios do Estado do Rio de Janeiro, pelo ensaio imunoenzimático indireto, associando-se os resultados com a presença de carrapatos nestes animais. de 199 cães examinados, 15,58% estavam positivos, com títulos que variaram de 400 (13,57%) a 1600 (0,5%). Os casos positivos se distribuíram uniformemente nos sete municípios. Não houve diferença estatística (P > 0,05) de soropositivos entre as faixas etárias dos cães acima de seis meses. Carrapatos foram encontrados e coletados em 71 (35,68%) cães, dos quais 24,1% estavam infestados com Amblyomma cajennense, 13,6% com Rhipicephalus sanguineus, 2,5% com Amblyomma aureolatum e 1,5% com Amblyomma ovale. Dos animais soropositivos para B. burgdorferi, 38,7% apresentavam A. cajennense e 22,6% apresentavam R. sanguineus, não havendo, entretanto, correlação positiva entre a presença do carrapato e sorologia positiva.

Report on ticks collected in the Southeast and Mid-West regions of Brazil: analyzing the potential transmission of tick-borne pathogens to man

Foram coletados espécimes de carrapatos em 1993, 1996, 1997, e 1998, principalmente de animais selvagens e domésticos, nas Regiões Sudeste e Centro-oeste do Brasil. Nove espécies de Amblyommidae foram identificadas: Anocentor Nitens, Amblyomma cajennense, Amblyomma ovale, Amblyomma fulvum, Amblyomma striatum, Amblyomma rotundatum, Boophilus microplus, Boophilus annulatus e Rhipicephalus sanguineus. Analisou-se o potencial destas nove espécies de carrapatos como transmissores de patógenos para o homem. Um Flaviviridade Flavivirus foi isolado de espécimes de Amblyomma cajennense coletados de um capivara doente (Hydrochaeris hydrochaeris). Amblyomma cajennense é o transmissor principal da Rickettsia rickettsii (=R. rickettsi), o agente causador da febre maculosa no Brasil. Os mamíferos selvagens, principalmente capivaras e veados infestados por carrapatos vivem em próximo contato com gado, cavalos e cachorros, com quem compartilham os mesmos carrapatos, oferecendo risco de transmissão destas zoonoses silvestres aos animais domésticos e ao homem.

Histopathology of tick-bite lesions in naturally infested capybaras (Hydrochoerus hydrochaeris) in Brazil

In the present work features of tick-bite lesions were evaluated in capybaras naturally infested with Amblyomma cajennense and Amblyomma dubitatum ticks. Gross appearance of tick bite site was characterized by a mild swelling and erythema. Microscopic examination revealed the cement cone, a tube-like homogenous eosinophilic mass penetrating deep into the dermis. This structure was surrounded in the dermis by a cellular infiltrate and free eosinophilic granules and was associated to edema of variable intensity. Necrosis was a common feature deep in the dermis particularly at the far end of the eosinophilic tube. Hyperplasia, cellular edema and occasionally necrosis of keratinocytes could be seen at both sides of the ruptured epidermis. Cellular infiltrate was constituted overwhelmingly by polymorphonuclear leukocytes with eosinophilic granules. In capybaras cells with such features can be either eosinophils or heterophils (pseudoeosinophils), the latter being the equivalent of neutrophils of other mammals. Ultrastructural analysis of the cellular infiltrate revealed the predominance of heterophils over eosinophils. Mononuclear cells and mast cells and, in lesser numbers, basophils were also seen at skin attachment sites. The presence of heterophils in the reaction of capybaras against Amblyomma ticks is an outstanding feature but its role in the reaction to the tick is not known. It is however speculated that capybara heterophils might be associated with a more permissive environment for tick feeding and pathogen transmission as already shown for the equivalent cell type, the neutrophil, in the reaction of the dog against the Rhipicephalus sanguineus tick.

CROSS-REACTIVITY BETWEEN HARD TICK ANTIGENS

1. The present study was carried out to determine the target cells and tissues for anti-tick immunoglobulins using an indirect immunohistochemical technique.2. Sections in triplicate prepared from unfed ticks Rhipicephalus appendiculatus, R. evertsi and Amblyomma variegatum were used to assess the cross-reactivity of serum from guineapigs naturally infested with these tick species or immunized against them.3. The sections showed slight (+) to strong (++++) labelling of several structures in the tick body, e.g. salivary gland, gut lumen and malpighian tubules, depending on the serum used.4. The immune serum resulting from the immunization of guinea pigs with an extract of unfed nymphs of R. appendiculatus ticks showed the most intense cross-reactivity with the sections examined.

Ticks (Acari : Ixodidae) parasitizing humans in an Atlantic rainforest reserve of Southeastern Brazil with notes on host suitability

While conducting projects on ticks from deer and on tick ecology in animal trails in an Atlantic rainforest reserve in Southeastern Brazil, researchers of our group were bitten by ticks several times. Some of these episodes were recorded. Three species of adult ticks attached to humans: Amblyomma brasiliense Aragauo, Amblyomma incisum Neumann, and Amblyomma ovale Koch. Eight nymphal attachments with engorgement on humans were recorded. From these, six molted to adults of A. incisum, one to an adult of A. brasiliense, and one had an anomalous molting, therefore the adult tick could not be properly identified. Local reactions to tick attachment varied among individual hosts from almost imperceptible to intense. Especially itching, but hyperemia and swelling as well, were prominent features of the reaction. Overall it can be affirmed that human beings can be a physiologically suitable host species for ticks in the Atlantic rainforest and that itching was an important if not the major component of the resistance to tick bite.

Ticks associated with armadillo (Euphractus sexcinctus) and anteater (Myrmecophaga tridactyla) of Emas National Park, State of Goias, Brazil

This study was conducted in October 1998 and November 1999 in the Emas National Park (131,868 ha), a savanna-type cerrado region situated in the far south of Goias State, Brazil, near the geographic center of South America (15degrees-23degrees S; 45degrees-55degrees W). Animals were captured with the aid of nets and anesthetized (15 mg/kg ketamine + 1 mg/kg xylasine) in order to collect ticks for identification and to establish laboratory colonies. They included giant anteaters (Myrmecophaga tridactyla) (n = 4) and yellow armadillos (Euphractus sexcinctus) (n = 6). Free-living ticks (larvae, nymphs, and adults) were collected from the field by using a 1 X 2-m flannel cloth. Free-living ticks were identified as Amblyomma sp., A. cajennense, and A. triste. Adult ticks collected from anteaters were identified as Amblyomma cajennense and A. nodosum and from armadillos as A. pseudoconcolor and A. nodosum. The relevance of these host-tick relationships to possible mechanisms underlying emergence of tick-borne pathogens of importance to public health is discussed.