Detection of Rickettsia hulinii in ticks of the Haemaphysalis concinna species in Russia

The presence of Rickettsia hulinii was detected in ticks of the Haemaphysalis concinna species in the Asiatic part of Russia. It was the first detection of these rickettsiae outside the territory of the Chinese People's Republic. This tick is spread over a broken area and may occur in different regions of Eurasia. At present at least 3 rickettsial species of the tick-borne spotted fever group were found in Ixodes ticks on the territory of Eastern Siberia: R. sibirica, known to be the etiological agent of tick-borne rickettsiosis, R. hulinii with proved pathogenicity for laboratory animals and R.DnS14 with no data available on its pathogenicity.     

Two new species of Haemaphysalis Koch, 1844 (Acari: Ixodidae) in the H. (Rhipistoma) spinulosa subgroup,parasites of carnivores and hedgehogs in Africa

Haemaphysalis (Rhipistoma) princeps n. sp. (Acari: Ixodidae) and H. (R.) camicasi n. sp. are described based on adults. Adults of H. princeps n. sp. were mostly collected from various carnivores (Carnivora: Canidae, Felidae, Herpestidae, Mustelidae, Viverridae) and hedgehogs (Erinaceomorpha: Erinaceidae); few specimens were found on hare (Lagomorpha: Leporidae), various rodents (Rodentia: Muridae) and an antelope (Artiodactyla: Bovidae) in Benin, Burkina Faso, Cameroon, Chad, Côte d’Ivoire, Ghana, Mali, Nigeria, Senegal, South Sudan and Sudan. Few adults of H. princeps n. sp. were reared from nymphs collected on rodents (Rodentia: Muridae) and shrew (Soricomorpha: Soricidae). Adults of H. camicasi n. sp. were also mostly collected from various carnivores (Carnivora: Canidae, Felidae, Herpestidae, Mustelidae, Viverridae) and hedgehogs (Erinaceomorpha: Erinaceidae); few specimens were found on different rodents (Rodentia: Muridae, Nesomyidae, Sciuridae), hare (Lagomorpha: Leporidae) and bushbaby (Primates: Galagidae) in Benin, Burkina Faso, Cameroon, Central African Republic, Chad, Côte d’Ivoire, Nigeria, Senegal, South Sudan and Togo. Males and females of both species can be differentiated from each other and other H. spinulosa-like ticks by their size, pattern of punctations on conscutum/scutum, size of setae, shape of genital structures, size and shape of spiracular plates, dorsal cornua, posterodorsal and posteroventral spurs on palpal segments II and spur on coxae.

     

Description of two new species of Haemaphysalis Koch, 1844 (Acari: Ixodidae) from the H. (Rhipistoma) spinulosa subgroup,parasites of carnivores and other mammals in Africa

Systematic Parasitology - Haemaphysalis (Rhipistoma) latitudinis n. sp. (Acari: Ixodidae) and H. (R.) setosa n. sp. are described based on adults. Adults of H. (R.) latitudinis n. sp. were mostly...     

Combined focus of tick-borne encephalitis, tick-borne rickettsiosis and tularemia in the habitat of Haemaphysalis concinna in south central Siberia

For the first time in the Krasnoyarsk region the population Haemaphysalis concinna ticks were found to be infected with the causative agents of three natural focal tick-borne infections--tick-borne encephalitis, tick-borne rickettsiosis and tularemia. The existence of the combined natural focus of these three infections has been confirmed by epidemiological data. Ticks Dermacentor nuttalli also play a similar role in combined foci of tick-borne encephalitis and tick-borne rickettsiosis in these focal territories.     

Ability of Ixodes persulcatus, Haemaphysalis concinna and Dermacentor silvarum ticks to acquire and transstadially transmit Borrelia garinii

In China, the ability of Ixodes persulcatus, Haemaphysalis concinna and Dermacentor silvarum to transmit Borrelia spirochetes was determined under laboratory conditions. Results showed that all three tick species can acquire spirochetes by feeding on infected mice. However, the capability of the three species to maintain spirochetes was different. Only I. persulcatus is able to maintain spirochetes alive during molting, and subsequent tick stages transmitted the infection to naive mice. In H. concinna and D. silvarum ticks, spirochetes could not survive after the digestion period of blood and after the molting process was finished, spirochetes were no longer detected. Contrary to H. concinna and D. silvarum, I. persulcatus should be considered the principal vector of Lyme disease in north China.     

Haemaphysalis concinna (Acari: Ixodida): Persistent efficacy of doramectin in rabbits under laboratory conditions

In the present study, the persistent efficacy of doramectin (DOR) in rabbits infested by Haemaphysalis concinna was observed. DOR (200 µg/kg) was administered once to infested rabbits by subcutaneous injection. A total of 15 rabbits were allocated to three groups, which were observed for efficacy. On days 1–7, 8–14, 15–21 and 22–28 post-inoculation, the percent reduction of tick larvae in DOR treated rabbits was 100.0, 100.0, 86.7 and 61.7%, respectively; the percent reduction of nymphs was 100.0, 90.0, 75.0 and 65.0%, respectively; and the percent reduction of adults was 85.0, 65.0, 55.0 and 55.0%, respectively. In comparison, in untreated rabbits at the same time points (control group), the percent reduction of larvae was 5.0, 3.3, 5.0 and 5.0%, respectively, and there was no reduction of nymphs and adults in the untreated rabbits.     

Experimental transmission ofCowdria ruminantium (Rickettsiales) by the American reptile tickAmblyomma dissimile Koch, 1844

A Senegalese isolate of the rickettsiaCowdria ruminantium was transmitted transstadially by nymphs of the American reptile tickAmblyomma dissimile. Only eight nymphs, fed as larvae on a Saanen goat reacting to heartwater, were required to transmit fatal heartwater to another susceptible goat.SinceA. dissimile usually feeds on snakes, iguanas and lizards in central America, the tick is not considered to play a significant role in the transmission of heartwater between ruminants. However, the tick could play a role in maintaining a rickettsial reservoir in reptile populations, since it has been shown that an African reptile can be a subclinical carrier ofC. ruminantium, infective to vector ticks.     

Description of a new species of Haemaphysalis Koch, 1844 (Acari: Ixodidae) from the H. (Rhipistoma) asiatica subgroup,parasite of an endemic Malagasy carnivoran (Carnivora: Eupleridae)

Systematic Parasitology - Haemaphysalis (Rhipistoma) galidiae n. sp. (Acari: Ixodidae) is described herein based on males and a single female. Adults of H. galidiae n. sp. were collected from the...     

Tick infection rates with Borrelia Ixodes ricinus versus Haemaphysalis concinna and Dermacentor reticulatus in two locations in eastern Germany

Unfed nymphal Ixodes ricinus, Haemaphysalis concinna, and adult Dermacentor reticulatus were collected in two locations of Saxony in July and September 1991 by flagging. In July, the abundance of nymphal I. ricinus was about 2-3 times higher than that of nymphal H. concinna, a time of the year when nymphs of both species are reported to have a seasonal peak of activity. No D. reticulatus were flagged concurrently. In September, host-seeking activity of nymphal I. ricinus was again quite high as was that of adult D. reticulatus but only low numbers of nymphal H. concinna were collected. The flagged ticks were individually examined for Borrelia by an indirect immunofluorescence assay (I. ricinus: n = 414; H. concinna: n = 96; D. reticulatus: n = 116). The prevalence of Borrelia (probably B. burgdorferi) in I. ricinus varied from 12.1% to 21.0%. No borreliae were found in H. concinna. Of the examined D. reticulatus from one site (n = 97) 11.3% contained either B. burgdorferi or a related Borrelia. This may be the first finding of Borrelia in an Eurasian Dermacentor species.     

Studies on the ecology of Amblyomma marmoreum Koch 1844 (Acarnia: Ixodidae).

In the Eastern Cape Province of South Africa, larvae and nymphs of Ablyomma marmoreum Koch occur in habitats in which there is tree cover and herbaceous ground cover. Immatures of A. marmoreum are parasitic on reptiles, birds, and mammals. Adults occur only on reptiles. The major host for all stages is the moutain tortoise (Geochelone pardalis), and in the home areas of tortoises the density of ticks is high. Larvae are active in late summer and autumn. The rate of feeding is temperature-dependent, and some larvae which attach on tortoises in late autumn do not complete feeding until the following spring. Nymphs which occur in the home area of a tortoise become active in response to CO2 in early spring. Adults, and nymphs which occur outside the home area of a tortoise, become active in summer in response to rising temperatures. In nymphs which feed in spring, and hence develop into adults in midsummer, the life cycle is completed in 1 year. In nymphs which fed in midsummer, the life cycle is completed in 2 years.     

Host-parasite relationships of the genus Hyalomma Koch, 1844 (Acari, Ixodidae) and their connection with microevolutionary process

Host-parasite relationships of Hyalomma species of the world fauna are analyzed. The majority of species infests predominately various mammals. Birds and reptiles are used as preferred hosts by several Hyalomma species, and only on certain stage: adults of H. aegyptium parasitize tortoises; immature stages of H. marginatum parasitize birds. It is hypothesized that relationships of H. aegyptium adults (subgenus Hyalomma s. str.) with reptiles are secondarily in origin. Immature stages of H. aegyptium retain the primary wide diapason of hosts, which are various small mammals, birds and reptiles. The life cycle of this species is the three-host type that is considered as a primary type in ixodid ticks. A typical scheme of relationships with their hosts in all well-examined Hyalommina species has following features: the adult stage parasitize large and medium sized mammals, immature stages parasitize small mammals, three-host life cycle. A variety of preferred hosts and types of life cycle is observed in the subgenus Euhyalomma. All species of this subgenus can be arranged into two groups. In the first group, the immature stages infest only small mammals and birds, and the adults parasitize large mammals; this type of host preferences is probably primary host-parasite relationships of Hyalomma. This group includes: H. albiparmatum, H. asiaticum, H. excavatum, H. franchinii, H. impeltatum, H. impressum, H. lusitanicum, H. marginatum, H. nitidum, H. schulzei, and H. truncatum. Hyalomma marginatum and H. schulzei are two-host species; H. excavatum is two- or three-host tick. All the remaining species (except H. albiparmatum, which life cycle is unknown) are three-host ticks. In the second group, the immature stages as well as the adult stage parasitize large mammals. This group includes: H. dromedarii, H. anatolicum, and H. scupense. These species are two- or one-host ticks.     

History of the geographic ranges and migration routes of ticks in the genus Dermacentor Koch, 1844 (Ixodidae)

The mutually checking parasitological and zoogeographic criteria for the issue in question made it possible to express the viewpoint and present supporting data on the origin and spread of Dermacentor ticks. Their origin was dated back to Oligocene (38 mln years ago). Having appeared in Angar Mainland, the ticks spread by land in Europe, North America (Miocene, 25 mln years ago) and Africa (Pliocene, 5 mln years ago). The list of species according to zoogeographic regions is given.     

Description of a new species of Dermacentor Koch, 1844 (Acari: Ixodidae) from Laos and Thailand

Systematic Parasitology - Dermacentor laothaiensis n. sp. (Acari: Ixodidae) is described based on adults ex wild boar and vegetation from Laos and Thailand. Adults of D. laothaiensis n. sp. are...     

Amblyomma triste (Koch, 1844) (Acari: Ixodidae): morphological description of the ovary and of vitellogenesis

The present study presents the morphology, histology, and the dynamics of vitellogenesis in females of the tick Amblyomma triste. The ovary in this species is of the panoistic type, therefore it lacks nurse cells. It is composed of a layer of epithelial cells that outwardly form the wall of the ovary, but also originate the pedicel, the structure that attaches the oocytes to its external margin, as well the oocytes themselves. In Amblyomma triste, the oocytes develop in four synchronic stages, which differs from the process in other tick species. The classification of the stages of the oocytes was carried out based on the presence of four morphologic characteristics: cytoplasm appearance; site of the germ vesicle; presence, quantity, and constitution of the yolk granules and presence of chorium.