Notas de Ixodologia: IV - considerações sôbre a nomeclatura de algumas espécies do gênero Amblyomma do Brasil e países limítrofes (Acari: Ixodidae)

An attempt is made to clear the nomenclature of some netropical species of the genus Amblyomma. Amblyomma myrmecophagium Schulze, 1933 and Amblyomma brasiliense guyanense Floch et Abonnenc, 1933, are synonyms of Amblyoma scalpturatum Neumann, 1906. Amblyomma superbrasiliense Schulze, 1941, is cospecific with Amblyomma incisum Neumann, 1906. Amblyomma ypsilophorum Schulze, 1941, is a synonym of Amblyomma cooperi Nuttal et Warburton, 1907.

Notas de ixodologia: V - A propósito da validade de algumas espécies do gênero Amblyomma do continente americano (Acari: Ixodídoe)

a) The species Amblyomma tapiri Tonelli Rondelli, 1937 and Amblyomma finitimum Tonelli Rondelli, 1937 are synonymous with Amblyomma cajennense Fabricius, 1787. Both species are based in differences of size, colour, punctations and form of the dorsal shield, presence or absence of ventral plates, size, form and direction of the spine of coxa IV. Such differences prouved to be only variations frequently observed in large lots or in cultures of Amblyomma cajennense. The revalidation of Koch's species Amblyomma tenellum Koch, 1844 and Amblyomma mixtum Koch, 1844 proposed by TONELLI RONDELLI as also of Amblyomma sculptum Berlese, 1888 and Amblyomma versicolor Nuttal et Warburton, 1908 cannot be accepted by the same reasons. b) Amblyomma beccari Tonelli Rondelli, 1939 and Amblyomma latepunctatum Tonelli Rondelli, 1939 are cospecific with Amblyomma scalpturatum Neumann, 1899 the same being true for Amblyomma myrmecophagium Schulze, 1935 and for Amblyomma brasiliense var. guianense Floch et Abonnenc, 1940, as previously stated. c) Amblyomma tasquei Floch et Abonnenc, 1940 is a good species but synonym with Amblyomma romitii Tonelli Rondelli, 1939 which has priority. d) Amblyomma curruca Schulze, 1936 is a synonym of Amblyomma parvum Aragão, 1908. e) Amblyomma deminutivum Neumann, 1899 represents a variation of Amblyomma dissimile Koch, 1844, a species whose internal spine of coxa IV may be poorly developed or even absent. f) Amblyomma nigrum Tonelli Rondelli, 1939 prouved to be synonym with Amblyomma paccae Aragao, 1911 the type representing a blackish specimen of the later species. g) Amblyomma brimonti Neumann, 1913 is a synonym of Amblyomma humerale Koch, 1844.

Notas de ixodologia: VI - Descrição da fêmea de Amblyomma Multipunctum, Neumann 1899 e redescrição do macho (Acari: Ixodídae)

The female of Amblyomma multipunctum Neumann, 1899 is described for the first time, the species being easily recognized by the unusual formula 5/5 in the female's hypostoma, the formula of the male's being 4/4. A redescription of the male is presented.

Structure of the salivary glands of the unfed female tick Amblyomma cajennense (Fabricius) (Acarina: Ixodidae)

Acini in in the salivary glands of female tick specimens of Amblyomma ajennense unfed at both postnymphal and adult phases, were studied. The salivary glands are consisted by three acini, one agranular and two granular. The agranular acini are directly attached to the anterior portion of the main salivary duct, consisting of cells without valve. A relatively large, clear, central cell occupies most of the alveolar midsection. The central cell is in contact with the acini lumen. Granular acini consist of approximately seven to fourteen cells (type II acini) or seven to sixteen (type III acini). The type II acini have three types of granular cells ("a", "b" and "c") and valve; the type III acini have another three types of granular cells ("d", "e" and "f") also presenting a valve.

Structure of the salivary glands of the unfed male tick Amblyomma cajennense (Fabricius) (Acarina: Ixodidae)

Acini in the salivary glands of unfed male Amblyomma cajennense of different ages, were studied. The salivary glands consist of one agranular and three granular acini types. The agranular acini are directly attached to the medial and anterior portion of the main salivary duct, and to some branches of the secondary ducts. A large, clear, central cell occupies the centre and this cell is in contact with the acinar lumen. There is no valve to the lumen. Granular acini consist of approximately six to fourteen cells (type II acini) or eight to thirteen (type III acini). The type II acini have three types of granular cells ("a", "b" and "c") and a valve: the type III acini have three types of granular cells ("d", "e" and "f" and a valve.

Notes on the biology of Amblyomma dissimile Kock, 1844 (Acari: Ixodida) on Bufo marinus (Linnaeus, 1758) from Brazil

Amblyomma dissimile is a common ectoparasite of cold blooded animals and is an accidental ectoparasite of some wild mammals. Details of the biology of specimens from the State of Amapá were studied in the laboratory in a humidity chamber at an average environmental temperature of 19.5 °C, using Bufo marinus as host for the time in Brazil. We also report the first record of this species in the State of Minas Gerais.

Primary isolation of spotted fever group rickettsiae from Amblyomma cooperi collected from Hydrochaeris hydrochaeris in Brazil

This paper reports the first isolation of a spotted fever group rickettsia from an Amblyomma cooperi ixodid collected from a capybara (Hydrochaeris hydrochaeris) in an endemic area of spotted fever in the County of Pedreira, State of São Paulo, Brazil. Isolation was performed in Vero cell culture and submitted to immunofluorescence, using antibody from Rickettsia rickettsii-positive human serum.

Rickettsiae-infected Ticks in an Endemic Area of Spotted Fever in the State of Minas Gerais, Brazil

A study on tick-borne rickettsiosis was developed in the county of Santa Cruz do Escalvado, State of Minas Gerais, Brazil, where a clinical case of the disease, confirmed by necropsy, had been reported. Of the 1,254 ticks collected, 1,061 belonged to the Amblyomma genus, 57 to the Rhipicephalus sanguineus species, 81 to Boophilus microplus, and 46 to Anocentor nitens. The hemolymph test associated with Giménez staining showed that 18 of the 221 A. cajennense specimens, 1 of the 16 R. sanguineus, 1 of the 22 B. microplus, 3 of the A. nitens, and 1 of the A. ovale contained rickettsia-like microorganisms. Only 3 A. cajennense ticks were positive under direct immunofluorescence. A. cajennense was the only species found on humans

Artificial Feeding of Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae) through Silicone Membrane

An artificial feeding system was used where citrated bovine blood was offerred to male and female Amblyomma cajennense. Vestiges of blood, sweat, hair and exfoliated skin were used as phago-stimulants placed on the surface of the silicone membrane. The ticks were collected, as engorged nymphs, from naturally infested equines, with the ecdysis occurring in the laboratory. Four hundred ticks were used, 50% being female, at three to four weeks post-ecdysis. Vestiges of blood on the silicone membrane were the most efficient phago-stimulant and the association of vestiges of blood and sweat residue smears yielded better results compared to the other phago-stimulants used

Host Specificity of Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae) with Comments on the Drop-off Rhythm

The parasitic specificity of larval, nymph and adult Amblyomma cajennense on six different host species: Oryctolagus cuniculus, Rattus norvegicus, Gallus gallus domesticus, Anas platyrhynchus, Coturnix coturnix and Streptopelia decorata is described. In terms of the numbers of larvae and nymphs recovered, O. cuniculus was the best host species. The modal day for drop-off of larvae and nymphs was day three for the mammal hosts, but variable in the birds. We conclude that adult A. cajennense have a strong degree of specificity due to the fact that the tick failed to complete its life cycle on any of the evaluated hosts. The immature stages, on the other hand, showed a low level of specificity, most especially in the larval stage, indicating the existence of secondary hosts which probably serve as dispersers in the wild. The results also indicated a variable drop-off rhythm for larvae and nymphs in two periods, diurnal (6-18 hr) and nocturnal (18-6 hr), which differed depending upon the host.

Wild birds as hosts of Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae)

We evaluated the prevalence, mean intensity and relative density of ticks in 467 wild birds of 67 species (12 families) from forest and cerrado habitats at two protected areas of Minas Gerais, between March and September 1997. Ticks collected (n=177) were identified as larvae and nymphs of Amblyomma cajennense and four other species of Amblyomma. We report for the first time 28 bird species as hosts of the immature stages of A. cajennense, demonstrating the lack of host specificity of the larvae and nymphs. A. cajennense had 15% prevalence on birds, with a mean infestation intensity of 0.37 ticks per host sampled, and 2.5 ticks per infested bird. Prevalence varied in relation to host species, diet and between birds from forests at two successional stages. There were no differences in relation to host forest dependence, participation in mixed flocks of birds, and nest type constructed. A. cajennense is a species of medical and veterinary importance, occurring on domestic animals but is known little of its occurrence on wildlife.

Lack of parthenogenesis by Amblyomma cajennense (Acari: Ixodidae)

Some reproductive parameters of adult stages of Amblyomma cajennense ticks were studied. The capacity of virgin females to reproduce by parthenogenesis was evaluated, during an experimental infestation, in absence of males, on a horse (Equus cabalus). Ticks were spread either completely free or in limited sites on the body of the animal. The engorged virgin females showed longer feeding periods and lighter body weights than those that had been fertilized. Some of these unmated females produced smaller egg masses, which had no embryonary development. On the other hand, females that had been inseminated produced larger egg masses, with normal embryonary development that led to viable larvae. Under the studied conditions, A. cajennense females did not reproduce by parthenogenesis.

Biology of Amblyomma aureolatum (Pallas, 1772) (Acari: Ixodidae) on some laboratory hosts in Brazil

The ixodid Amblyomma aureolatum is suspected to play a role in the epidemiology of wild life-cycle hemoparasites, which frequently infect dogs in rural and hunting areas in Brazil. Little is known about its bionomics. The objective of the present study was to evaluate some bionomic aspects of A. aureolatum ticks in Brazil. One engorged female, collected from a dog (Canis familiaris) in São Sebastião das Águas Claras, State of Minas Gerais, was used to establish a colony in the laboratory. Subsequently its parasitic stage progeny were fed on domestic dogs and laboratory animals. The free-living stages were incubated at 27ºC ± 2°C and minimum 70% relative humidity in a BOD incubator. The egg incubation period ranged from 31 to 34 days; the parasitic period of larvae ranged from 4 to 6 days and ecdysis to nymphs occurred from day 19 up to day 22. The parasitic period of nymphs ranged from 5 to 8 days and the period of ecdysis to adults from 31 to 33 days. The parasitic period of adults ranged from 11 to 15 days, the pre-oviposition period from 6 to 12 days, and the oviposition period from 9 to 38 days. The total duration of the life cycle ranged from 116 to 168 days.