Reactions to shrimp including severe anaphylaxis in mite- and cockroach-allergic patients who have never eaten shrimp: clinical significance of IgE cross-reactivity to tropomyosins from different sources

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Description of a new soft tick species (Acari: Argasidae: Ornithodoros) associated with stream-breeding frogs (Anura: Cycloramphidae: Cycloramphus) in Brazil

In this study, we present a morphological description of immature and adult specimens of Ornithodoros saraivai n.sp., a tick associated with the frog Cycloramphus boraceiensis (Cycloramphidae) at São Sebastião island, located in the São Paulo state seaboard, Brazil. While larvae of O. saraivai are ecologically related to Ornithodoros faccinii, another soft tick associated with cycloramphids, the combination of 7 sternal pairs, 16 dorsal pairs, a pyriform dorsal plate and a partially toothed hypostome constitute unique characters of the O. saraivai larvae. One undetermined nymphal instar and adults of O. saraivai are similar to mature specimens of the Ornithodoros talaje species group; however, the O. saraivai specimens can be recognized by the presence of a robust bean-shaped spiracle with a large spiracular plate and more than two long seta in palpal article I. Identical partial sequences of the mitochondrial 16S rDNA gene confirmed the identity for all collected stages and for two cohorts of laboratory-reared larvae of O. saraivai. A Bayesian and Maximum Parsimony inferred phylogenetic trees supportthe position of O. saraivai in a clade with O. faccinii, suggesting the existence of an Ornithodoros lineage that evolved in association with amphibians...

Isolation of the Pathogen Rickettsia sp Strain Atlantic Rainforest From Its Presumed Tick Vector, Amblyomma ovale (Acari: Ixodidae), From Two Areas of Brazil

In this study, Amblyomma ovale Koch ticks were collected from domestic dogs in two localities of the Atlantic rainforest biome of Brazil: 1) the Paty Valley of the Chapada Diamantina National Park, Bahia state (northeastern Brazil), and 2) Adrianopolis, Parana state (southern Brazil). Ticks were screened for the presence of Rickettsia-like structures by the hemolymph test with Gimenez staining, and then processed for isolation of rickettsiae in Vero cell culture by the shell-vial technique. Rickettsiae were isolated from one A. ovale tick of each of the two localities. The two isolates were successfully established in the laboratory with several passages, each one reaching >90% infection of the cells. The two isolates were identified as the spotted fever group (SFG) agent Rickettsia sp. strain Atlantic rainforest, as their gltA (350 bp), ompB (781 bp), and ompA (567 bp) gene fragments were 100% equal to GenBank corresponding sequences of the original strain Atlantic rainforest, reported to be infecting a human in southeastern Brazil, and also 100% equal to the available ompA sequence of strain Bahia, reported to be infecting a human in Paty Valley, the same area of the present study in Bahia state. Ten dogs from Paty Valley were serologically tested against rickettsial antigens by the indirect immunofluorescence antibody test. At least 60% of them were seroreactive to SFG rickettsiae. The role of A. ovale as vector of Rickettsia sp. strain Atlantic rainforest in the Paty Valley area, as well as in other parts of Latin America, is discussed.

Geographical distribution of Amblyomma cajennense (sensu lato) ticks (Parasitiformes: Ixodidae) in Brazil, with description of the nymph of A-cajennense (sensu stricto)

Background: Until recently, Amblyomma cajennense (Fabricius, 1787) was considered to represent a single tick species in the New World. Recent studies have split this taxon into six species. While the A. cajennense species complex or A. cajennense (sensu lato) (s.l.) is currently represented by two species in Brazil, A. cajennense (sensu stricto) (s.s.) and Amblyomma sculptum Berlese, 1888, their geographical distribution is poorly known. Methods: The distribution of the A. cajennense (s.l.) in Brazil was determined by morphological examination of all lots of A. cajennense (s.l.) in two large tick collections of Brazil, and by collecting new material during three field expeditions in the possible transition areas between the distribution ranges of A. cajennense (s.s.) and A. sculptum. Phylogenetic analysis inferred from the ITS2 rRNA gene was used to validate morphological results. Morphological description of the nymphal stage of A. cajennense (s.s.) is provided based on laboratory-reared specimens. Results: From the tick collections, a total 12,512 adult ticks were examined and identified as 312 A. cajennense (s.s.), 6,252 A. sculptum and 5,948 A. cajennense (s.l.). A total of 1,746 ticks from 77 localities were collected during field expeditions, and were identified as 249 A. cajennense (s.s.), 443 A. sculptum, and 1,054 A. cajennense (s.l.) [these A. cajennense (s.l.) ticks were considered to be males of either A. cajennense (s.s.) or A. sculptum]. At least 23 localities contained the presence of both A. cajennense (s.s.) and A. sculptum in sympatry. DNA sequences of the ITS2 gene of 50 ticks from 30 localities confirmed the results of the morphological analyses. The nymph of A. cajennense (s.s.) is morphologically very similar to A. sculptum. Conclusion: Our results confirmed that A. cajennense (s.l.) is currently represented in Brazil by only two species, A. cajennense (s.s.) and A. sculptum. While these species have distinct distribution areas in the country, they are found in sympatry in some transition areas. The current distribution of A. cajennense (s.l.) has important implications to public health, since in Brazil A. sculptum is the most important vector of the bacterium Rickettsia rickettsii, the etiological agent of Brazilian spotted fever

Rickettsial agents in avian ixodid ticks in northeast Brazil

Birds are important in the maintenance and spread of ticks and tick-borne diseases. In this context we screened birds in the Atlantic forest north of the São Francisco River and Caatinga in northeast Brazil. In the Atlantic forest Amblyomma longirostre, Amblyomma nodosum, Amblyomma varium and Amblyomma auricularium were identified. A. longirostre was infected by “Candidatus Rickettsia amblyommii” and A. nodosum by a Rickettsia parkeri-like agent. In Caatinga, Amblyomma parvum and A. auricularium were identified. A. auricularium was infected by “Ca. R. amblyommii” and Rickettsia bellii. “Canditatus Rickettsia andenae” was also identified in A. parvum collected from birds in Caatinga. In addition, Rickettsia sp. genotype AL was identified in A. varium collected on the clothes of the field team in one area of Atlantic forest. Here we provide a series of new host records for several Neotropical Amblyomma species and document rickettsial infections of “Ca. R. amblyomii” and a R. parkeri-like agent in Paraíba State, and R. bellii and “Ca. R. andenae” in Bahia State. For the first time we provide information regarding the infection of A. varium by “Ca. R. amblyommii”...

Epidemiology of Brazilian spotted fever in the Atlantic Forest, state of São Paulo, Brazil

The tick-borne bacterium Rickettsia rickettsii is the a etiological agent of Brazilian spotted fever (BSF). The present study evaluated tick infestations on wild and domestic animals, and the rickettsial infection in these animals and their ticks in 7 forest areas adjacent to human communities in the São Paulo Metropolitan Area (SPMA). The results were compared to ecological traits of each sampled area. Two main tick species, Amblyomma aureolatum and Rhipicephalus sanguineus, were collected from dogs. The major ticks found on small mammals and birds were Ixodes loricatus and Amblyomma longirostre, respectively. Both anti-R. rickettsii antibodies and R. rickettsii-infected ticks were detected on dogs from only 2 areas in the southern part of the SPMA, which were considered to be endemic for BSF; the remaining 5 areas were considered to be non endemic. Ecologically, the BSF-endemic areas clearly differed from the non-endemic areas by the presence of significantly more degraded forest patches in the former. The present results corroborate historical observations that have indicated that all human cases of BSF in the SPMA were contracted in the southern part of this metropolitan area. However, not all forest patches in the southern part of the SPMA were shown to be associated with BSF endemism...

Amblyomma dissimile Koch (Acari: Ixodidae) attacking Primolius maracana Vieillot (Psittaciformes: Psittacidae) in the Amazon region, state of Pará, Brazil

The tick Amblyomma dissimile Koch feeds preferentially on reptiles (Squamata), although amphibians (Anura) also seem to be important hosts. We report an A. dissimile nymph infesting a blue-winged macaw, Primolius maracana, held in captivity in the Mangal das Garças Park, State of Pará, Brazil. Environmental observations suggest that free-living iguanas (Iguana iguana), which used to walk on the bird enclosure in the park, were the source of the A. dissimile tick that infested the blue-winged macaw. We provide the second world record of a bird host for A. dissimile, and the first bird record for this species in South America.

Experimental Infection of Amblyomma aureolatum Ticks with Rickettsia rickettsii

We experimentally infected Amblyomma aureolatumticks with the bacterium Rickettsia rickettsii, the etiologicagent of Rocky Mountain spotted fever (RMSF). These ticksare a vector for RMSF in Brazil. R. rickettsii was effi cientlyconserved by both transstadial maintenance and vertical(transovarial) transmission to 100% of the ticks through4 laboratory generations. However, lower reproductive performance and survival of infected females was attributedto R. rickettsii infection. Therefore, because of the highsusceptibility of A. aureolatum ticks to R. rickettsii infection,the deleterious effect that the bacterium causes in theseticks may contribute to the low infection rates (<1%) usuallyreported among fi eld populations of A. aureolatum ticksin RMSF-endemic areas of Brazil. Because the numberof infected ticks would gradually decrease after eachgeneration, it seems unlikely that A. aureolatum ticks couldsustain R. rickettsii infection over multiple successivegenerations solely by vertical transmission...

Comparative susceptibility of larval stages of Amblyomma aureolatum, Amblyomma cajennense, and Rhipicephalus sanguineus to infection by Rickettsia rickettsii

The current study compared the susceptibility of larval stages of Amblyomma cajennense (F.), Amblyomma aureolatum (Pallas), and Rhipicephalus sanguineus (Latreille) to infection by a Brazilian strain of Rickettsia rickettsii. Guinea pigs experimentally infected by R. rickettsii were simultaneously infested by larvae of the three tick species. Recovered engorged larvae were allowed to molt to nymphs and held in an incubator at 23°C and 85–90% RH. Subsequent flat nymphs were tested for rickettsial infection by polymerase chain reaction (PCR). Concomitant infestations with sibling ticks on noninfected guinea pigs (control) were done. While 10–60% of the A. cajennense nymphs were shown to be infected by R. rickettsii, both A. aureolatum and R. sanguineus were highly susceptible to R. rickettsii, since 80–100% of their nymphs were shown to be infected in the corresponding trials ...