Examination Of Ticks Research Articles

Acarine ectoparasites of Panti Forest Reserve in Johore, Malaysia

Objective To identify the presence of acarine ectoparasites and determine whether there is any potential public health risk in Panti Forest Reserve, Johore, Malaysia. Methods Trapping of animals and avifauna was conducted simultaneously along 5 expedition trails using 150 wire traps, 10 harp traps and 30 mist nets for 6 consecutive nights. A total of 140 animals consisting of 7 species of birds, 19 species of bats, 6 species of rodents and 1 species of tree–shrew as well as 8 myriapods were examined. Results Infestation rates of ticks, mesostigmatid mites and chiggers on animals examined were 24.3%, 28.6% and 27.9%, respectively. Infestation on bats was low (1.5%) and none occurred on birds. Majority of ticks extracted were at immature stages (78.9%). Genera of ticks on animals were Amblyomma, Dermacentor, Haemaphysalis and Ixodes. Ixodes granulatus was the only species of ticks identified from the animals. Examination of ticks under vegetation revealed 54% adults leading to identification of 3 species of ticks. A total of 7 species of mesostigmatid mites were found. 6 species were on rodent, Maxomys surifer and another one species, Laelaps nuttalli was found only on Leopoldamys sabanus. Laelaps sanguisugus was the only mesostigmatid found infesting tree-shrews. Seven genera of chiggers were identified. From this, 5 genera were on rodents, 4 genera on tree–shrews and 1 genus on a bat. Conclusions A total of 16 genera, 2 sub–genus and 14 species of acarine ectoparasites were found in this area. Findings of the survey demonstrate the presence of three spesies of acarine ectoparasites which have potential health risk i.e. Ixodes granulatus, Laelaps nuttalli and Leptotrombidium deliense.

Distributions of the paralysis ticks Ixodes cornuatus and Ixodes holocyclus in south‐eastern Australia

To describe the actual and potential geographic distributions of Ixodes cornuatus and I holocyclus in south-eastern Australia. Examination of ticks from museum collections and trapped animals were made. (Bioclimatic analysis BIOCLIM) was used to predict potential distributions. I holocyclus was collected from rodents (Rattus fuscipes, R lutreolus, R rattus), wombats (Vombatus ursinus), cats and dogs in Gippsland and I cornuatus was collected from rodents (R fuscipes), wombats, cats and dogs in central Victoria. All life-cycle stages of both species were collected during the warmer months of the year. The known distribution of the two species was established from specimens in museum collections and suggested that a boundary between the two may exist in eastern Gippsland. BIOCLIM suggested that the area immediately to the east of Melbourne was climatically suitable for I holocyclus, although no endemic foci of infection are currently known from this region. The potential distribution of I cornuatus included east Gippsland and the Otway Ranges, areas in which the tick is not currently known to occur. I holocyclus and I cornuatus have more restricted distributions than current collections suggest and therefore may have the possibility to extend their geographical ranges in the future.

Foci of tick-borne diseases in Southwest Germany

Presently known tick-borne diseases in Germany include Lyme borreliosis, tick-borne encephalitis (TBE-virus, western subtype), Q-fever, babesiosis and presumably ehrlichiosis. Blood samples of 4,368 forestry workers in the State of Baden-Wuerttemberg (B-W), southwestern Germany, were tested for the presence of antibodies against Borrelia burgdorferi sensu lato, TBE-virus and Ehrlichia spp. (genogroup E. phagocytophila). Furthermore 12,327 ticks ( Ixodes ricinus) collected in various areas of B-W were analysed by PCR and genotyping for the prevalence of pathogen RNA and DNA. The human seroprevalence rates of antibodies to B. burgdorferi sensu lato ranged from 18 % to 52 %, for TBE-virus from 0 % to 43 % and for Ehrlichia spp. from 5 % to 16 % in various counties of the State. The foci of B. burgdorferi and TBE-virus as indicated by antibody prevalence in humans are only partly overlapping with each other. The highest rates of TBE-virus antibodies are in concordance with available clinical data. However antibody prevalence up to 27 % in areas with no reports of clinical cases was found, suggesting that TBE occurs throughout the State of B-W, The prevalence of Ehrlichia spp. antibodies suggests that ehrlichiosis plays a role as a tick-borne disease in Germany, but as long as no clinical data are available, this will remain unclear. Investigations of ticks for TBE-virus (n = 9,189) by nested PCR showed prevalence rates from 0% to 2.3% and for Ehrlichia spp. (n = 1,963) from 2.6% to 3.1%. Examination of ticks (n = 3,138) for the presence of B. burgdorferi sensu lato DNA was performed by PCR and revealed prevalence rates from 13.9% up to 24%. Furthermore 1,106 samples positive for B. burgdorferi sensu lato were used for genotyping. B. afzelii DNA was found in 407 ticks (36.8%), followed by B. garinii (21.9 %), B. valaisiana (13.7%), and B. burgdorferi sensu stricto (9.9 %). Double infection was found in 6.4% and triple infection in 0.8% of the ticks. 10.5% of the positive samples could not be classified. Prevention of tick-borne diseases has to focus on behavioural intervention to reduce individual tick exposure by proper behaviour in the environment, as a large-scale control of the tick population seems impossible and thus reduction of Lyme borreliosis and TBE through tick control is unlikely. Vaccination against TBE-virus should not only be recommended for high endemic areas but also for persons with a high individual risk.

Transmission risk of Borrelia burgdorferi sensu lato from Ixodes ricinus ticks to humans in southwest Germany.

The risk of Borrelia burgdorferi infection and the value of antibiotic prophylaxis after tick bite are controversial. In this study, performed in two areas of southwestern Germany, ticks were collected from 730 patients and examined by the polymerase chain reaction (PCR) for B. burgdorferi. To assess whether transmission of B. burgdorferi occurred, the patients were clinically and serologically examined after tick removal and during follow-up examinations. Data from all tick bites gave a total transmission rate of 2.6% (19 patients). Eighty-four ticks (11.3%) were PCR positive. Transmission occurred to 16 (26.7%) of 60 patients who were initially seronegative and could be followed up after the bite of an infected tick. These results indicate that the transmission rate from infected ticks in Europe is higher than previously assumed. Examination of ticks and antibiotic prophylaxis in the case of positivity appears to be indicated.

Intraerythrocytic 'gametocytes' of Babesia microti and their maturation in ticks.

The electron microscopic study of several strains of Babesia microti provided evidence that this parasite has two types of organisms in the intraerythrocytic stage. In one, the trophozoites undergo differentiation and reproduce by formation of merozoites. In the other no differentiation or reproduction occurs and the parasites acquire an unusual shape. A hypothesis was put forward that the latter organisms might be gametocytes. This term has been used tentatively throughout this paper. An examination of ticks fed on hamsters' blood infected with B. microti has shown that parasites emerging from hemolyzed erythrocytes closely resemble the intraerythrocytic gametocytes in their shape. A reorganization and differentiation of the cytoplasm expressed in the appearance of new structures occurs. Among them the most striking is a complex organelle that looks like an arrowhead. Several arrowheads are found in a single gametocyte, each marking an incipient gamete. Most gametes are equipped with an arrowhead organelle, a tail, microtubules, and a cytostome. Occasionally a close apposition of two gametes and cytoplasmic fusion between the two organisms was found but it is not excluded that this might represent division. The use of the terms 'gametocyte' and 'gamete' is not yet fully justified. More evidence is needed.

The immature stages of Ixodes frontalis Panzer 1795.

When reviewing the status of Ixodes frontalis Panzer in an earlier paper (Arthur, 1952) the reference to Acarus (Ixodes) turdi Scopoli was not included, for the description might well apply to any tick. This is equally true for Panzer's description, and this name has been retained through popular usage. Neumann (1899) was the first worker to present a fairly clear account of this species but, as his host range shows, it may well have been clouded by reference to Ixodes brunneus Koch. The available descriptions refer to the female. Larvae have hitherto been neglected or else described as similar to the female, with the addendum that ‘in the larva the scutum is as broad as long’. Examination of ticks from a large number of birds has convinced me that in the past the immature stages of many species of ticks have, on this basis, been incorrectly determined. This may possibly be one reason for the suggested rarity of records of the immature stages of I. frontalis. In the present paper the larva of this species has been described. This description has been based on larvae sent to me by Mr John Ash.