Chemical identification of Tagetes minuta Linnaeus (Asteraceae) essential oil and its acaricidal effect on ticks / Caracterização química e efeito acaricida do óleo essencial de Tagetes minuta Linnaeus (Asteraceae) em carrapatos

The control of tick species that affect animal production is vital for the economic welfare of the cattle industry. This study focused on testing the acaricidal activity of the essential oil from the leaves and stems of Tagetes minuta against several Brazilian tick species, including Rhipicephalus (Boophilus) microplus, Rhipicephalus sanguineus, Amblyomma cajennense and Argas miniatus. The chemical composition of the essential oil was determined by chromatography and spectroscopy analyses, which revealed the presence of monoterpenes. The adult immersion test (AIT) and the larval packet test (LPT) were used to evaluate the efficacy of T. minuta essential oil in tick management at concentrations of 2.5, 5, 10, 20 and 40%. The results demonstrated that the T. minuta essential oil had over 95% efficacy against four species of ticks at a concentration of 20%. These results suggest that the essential oil of T. minuta could be used as an environmentally friendly acaricide.(AU)

O controle de carrapatos que causa impacto na produção de bovinos possui importância econômica para a cadeia produtiva. Neste trabalho objetivou-se testar a atividade acaricida do óleo essencial das folhas e caules de Tagetes minuta contra várias espécies de carrapatos brasileiros, incluindo Rhipicephalus (Boophilus) microplus, Rhipicephalus sanguineus, Amblyomma cajennense e Argas miniatus. A composição química do óleo foi determinada por GC-MS e análises de espectroscopia de RMN, que revelaram a presença de monoterpenos. Na avaliação destas substâncias no controle do carrapato foram empregados os testes de imersão de adulto (TIA) e o de pacote de larvas (TPL) para o extrato de óleo de T. minuta nas concentrações de 2,5%; 5%; 10%; 20% e 40%. Os resultados do TPL e TIA demonstraram que o óleo essencial na concentração de 20% de T. minuta apresenta eficácia superior a 95% nas quatro espécies de carrapato. Estes resultados sugerem que o óleo essencial de T. minuta pode ser usado como um acaricida eficaz e com baixo impacto ambiental.(AU)

Biocontrol of pigeon tick Argas reflexus (Acari: Argasidae) by entomopathogenic fungus Metarhizium Anisopliae (Ascomycota: Hypocreales)

The pigeon tick Argas reflexus is a pathogen-transmitting soft tick that typically feeds on pigeons, but can also attack humans causing local and systemic reactions. Chemical control is made difficult due to environmental contamination and resistance development. As a result, there is much interest in increasing the role of other strategies like biological control. In this study, the efficacy of three strains (V245, 685 and 715C) of entomopathogenic fungus Metarhizium anisopliae for biological control of three life stages of pigeon tick A. reflexus including eggs, larvae, engorged and unfed adults was investigated under laboratory conditions. Five concentrations of different strains of M. anisopliae ranging from 10³ to 10(7) conidia/ml were used. All fungal strains significantly decreased hatchability of A. reflexus eggs. Strain V245 was the most effective strain on the mortality of larval stage with nearly 100 percent mortality at the lowest concentration (10³ conidia/ml) at 10 days post-inoculation. The mortality rate of both engorged and unfed adult ticks were also increased significantly exposed to different conidial concentrations compared to the control groups (P < 0.05) making this fungus a potential biological control agent of pigeon tick reducing the use of chemical acaricides.

The influence of the fasting period on the number of nymphal instars and on the sex ratio of Argas (Persicargas) miniatus (Acari: Argasidae) / Influência do período de jejum no número de instares ninfais e na razão sexual de Argas (Persicargas) miniatus (Acari: Argasidae)

The current study investigated the biology of nymphs of the first and second instars of Argas (Persicargas) miniatus. Nymphs were deprived of food for 15, 30 or 60 days and held at 27 ± 1 ºC and 80 ± 10 percent relative humidity (controlled conditions) or at room conditions of temperature and relative humidity. Nymphs of first instar deprived of food for 15 or 30 days molted to second and third instars in both controlled and room conditions. Nymphs of the first instar deprived of food for 60 days had 28 and 37 percent mortality in controlled and room conditions, respectively; and survivors did not attach to the host. Nymphs of the second instar, deprived of food for 60 days, molted either to the third instar or to males after feeding on Gallus gallus, and the nymphs of the third instar developed to adults (42.42 percent males and 36.36 percent females when nymphs were held in controlled temperature and humidity conditions, and 40.54 percent males and 48.65 percent females when nymphs were held in room conditions). The remainder of the nymphs molted to the fourth instar and then molted to females. In conclusion, the nymphal starvation period of 60 days determined the number of nymph instars in the life cycle of A. miniatus under the experimental conditions studied.

Os aspectos biológicos de ninfas de primeiro e segundo instares de Argas (Persicargas) miniatus quando submetidas a diferentes períodos de jejum (15, 30 e 60 dias), foram estudados em estufa climatizada (27 ± 1 ºC e 80 ± 10 por cento de umidade relativa) e em ambiente de laboratório. Ninfas de primeiro instar que foram submetidas a um período de jejum de 15 e 30 dias mudaram para ninfas de segundo e terceiro instar, em ambas as condições estudadas. No período de 60 dias de jejum verificou-se mortalidade de 28 e 37 por cento das ninfas de primeiro instar, em estufa climatizada e em ambiente de laboratório, respectivamente. As ninfas sobreviventes não se fixaram sobre os hospedeiros. As ninfas de segundo instar, após 60 dias de jejum, desenvolveram-se em ninfas de terceiro instar ou machos, quando alimentadas em Gallus gallus. Ainda neste grupo, as ninfas de terceiro instar mudaram para adultos (42,42 e 40,54 por cento machos; 36,36 e 48,65 por cento fêmeas, nas condições ambiente de laboratório e estufa climatizada, respectivamente) e o restante desenvolveu-se em ninfas de quarto instar que por sua vez mudaram para fêmeas. Então, a situação de jejum (60 dias) em que as ninfas foram submetidas determinou o número de ninfas no ciclo biológico de A. miniatus, sob as condições experimentais estudadas.

Ultrastructure of normal and JHA-treated eggs of the soft tick argas persicus [oken]

The ultrastructure of normal development and JHA-treated egg was examined with the transmission electron microscope. In newly oviposited egg, the chorion consists of exo- and endochorion. Between the chorion and plasma membrane lies vitelline [envelope] membrane, a thin non cellular membrane. The periplasm is free of the yolk spheres with contains vesicles of various sizes and lipid inclusions, The endoplasm is rich in yolk spheres, mitochondria, lipid inclusions, dense vesicles and vacuoles. In 48 h-old egg, cleavage nuclei was seen migrating to the periphery of the egg. The ooplasm around the nuclei contains vesicles, endoplasmic reticulum and few mitochondria. The blastoderm cells contain many organelles and inclusions. Secondary vitellophages and pole cells were observed. In 96 h-old egg, the germ band is formed. It consists of two layers, ectoderm and mesoderm. Amnion and serosa were visible. At [0-1 hour] eggs post-treatment with JHA [Admiral], no real effects was observed except for vacuolation of endoplasm; while at 48 h and 96 h-old post-treatment of eggs, great deterioration were seen which ended by degeneration and lysis of cell components leaving cell debris, vacuolation of nuclei, iregular shape of nuclear membrane and dispersed chromatin material

Seasonal activity of ticks and their importance in tick- borne infectious diseases in west Azerbaijan, Iran

West Azerbaijan is considered as a main region for domestic animal breeding. Due to importance of herd as a main host and ticks as a vector of relapsing fever and CCHF, a comprehensive study was undertaken in the region. Outdoor, indoor collection as well as ticks stick to the animals' body were collected and identified. The study was conducted during the whole seasons in 2004-2005. During four seasons a total of 2728 ticks of two families [Ixodidae and Argasidae] were collected comprising 7 genera of 5 hard ticks and two genera of soft ticks including Haemaphysalis, Hyalomma, Rhipicephalus, Boophilus and Dermacentor. The soft ticks were Ornithodoros and Argas. These 7 genera included 18 species. The main species were Haemaphysalis inermis, H. punctata, H. sulcata, H. numidiana, H. concinna, Hyalomma marginatum, Hy. anatolicum, Hy. detritum, Hy. dromedarii, Hy. asiaticum, Hy. schulzei, H. aegyptium, Rhipicephalus bursa, R. sangiuneus, Dermacentor marginatus, Boophilus annulatus, Ornithodoros lahorensis, and Argas persicus. Frequency of ticks during different seasons was different. A pyrethroid insecticide, cypermethrin, which is widely used for tick control was tested against soft ticks. The test method was based on WHO recommendation. At the LD50 level A. persicus needs more concentration than O. lahorensis. Ornithodoros and Argas are the more prevalent soft ticks in the region. Distribution and prevalence of hard ticks was varied in different seasons. Results of this study will provide a clue for vectors of tick-borne diseases in the region for local authorities for implementation of tick control

Distribution of soft ticks and their natural infection with Borrelia in a focus of relapsing fever in Iran

Tick-borne diseases such as relapsing fever and Crimean-Congo Hemorrhagic Fever [CCHF] are of public health importance in Iran. There are 471 reported cases of relapsing fever in 2003, according to the Ministry of Health of Iran. The number of cases has been increased in recent years. Its distribution is more or less prevalent in different parts of Iran. The aim of this study was to find out the fauna and natural infection of soft ticks with Borrelia in Qazvin Province, during their seasonal activity. The province covers 15821 km[2] between 48-45 to 50-50 east of Greenwich Meridian of longitude and 35-37 to 36-45 north latitude of the equator. For this purpose a field study was carried out in the region. A total of 54 villages from 19 districts were selected randomly and ticks were collected from their habitats according to the standard method. A total of 3197 Argasidae ticks were collected from human dwellings, poultry and animal shelters. They belonged to Argas and Ornithodoros genera which 36.8% were Argas persicus, 4% A. reflexus, 6.4% O. canestrini, 45.5% O. lahorensis and 7.3% O. tholozani. It should be noted that 12 ticks of O. erraticus were collected from 12 rodents borrows. We found that 8.82% of O. tholozani ticks were infected with Borrelia persica and half of the O. erraticus were infected with Borrelia microti. All the people who are involved with veterinary activities should be aware of disease transmission by the ticks. In the endemic area of the disease tick control is recommended

Acaricidal efficacy of Myrrh [commiphora molmol] on the fowl tick argas persicus [acari: argasidae]

Five concentrations of purified extract of Myrrh from Commiphora molmol tree were prepared to study its effects on the fowl tick Argas persicus under laboratory conditions. The results revealed that Myrrh had dependant dose toxic effect on the adult female of A. persicus. Toxicity increased gradually daily post treatment. The LC 50 was 1.28%, 0.88%, 0.84%, 0.50% and 0.42% at 1st 2nd 3rd 6th and 12th days respectively. At 12th day, the recorded mortality rates were 63, 67, 76, 87 and 94% for concentrations. 0.625, 1.25, 2.5, 5 and 10%, respectively against 5% in control. Histopathological and Transmission election microscope [TEM] examinations showed the lysing of epithelial gut cells in treated groups. The lysed epithelial gut cells showed irregularly distributed nucleus, commonly at low concentrations and rarely in high concentrations of Myrrh. The lysed epithelial gut cells, without nucleus or with aggregated one beside the basal lamina. were common at high concentrations and rare in low concentrations of Myrrh. Consequently, Myrrh can rapidly penetrate the cuticle to body cavity, destroy the epithelial gut cells and finally cause the death of ticks

Aspectos morfológicos e quetotáxicos de larvas de Argas (Persicargas) miniatus (Acari: Argasidae) no Brasil / Morphology and chaetotaxy aspects of larvae of Argas (Persicargas) miniatus (Acari: Argasidae) in Brazil

Eggs were obtained from female Argas (Persicargas) miniatus parasitizing chickens after natural ovoposition. The larvae from eggs were sacrificed, prepared for and mounted onto slides. Morphological and chaetotaxic studies enabled the following observation: idiosome and gnathosome shape; presence or absence of scutum, eyes and anal setae; number of palpi segments; number of files of teeth on the hypostoma; number of denticles on the apical crow; number of cheliceral digits; number of teeth in each hypostoma file; disposition and shape of opistosoma and podosoma setae in ventral and dorsal view. Based on these morphological features analyzed, it is concluded that the larvae of A. (P.) miniatus present variations in morphology and chaetotaxy that are useful to separate the larvae of the subgenus Persicargas.

Study of Exoparasites, Rickettsia and Hantaan virus in Bats

To study the relation between ectoparasite, Rickettsia and hantaan virus in bats, four order of Athropoda were collected from Rhinolophus ferrumequinum captured in Cheju and Eptesicus serotinus captured in Chungnamin from July 1989 to March 1998. Also antibody of Rickettsia and hantaan virus were detected by immunofluoroscent antibody technique and RT-PCR. The results are as follows. 1. Five species of Acarina were identified from E. serotinus: Leptotrobidium subakamushi of Trombiculidae, Macronyssus coreanus, Steatonyssuss spinosuss and Steatonychus superans of Macronyssidae, Argas vespertilionis of Metastigmata. 2. Ischnopsyllus needhami of Siphonaptera and Cimex of Hemiptera were identified from E. serotinus. 3. Cyteribia uenoi and Brachytarsina kanoi of Diptera were identified from R. ferrumequinum. 4. The positive rate of rickettsial antibodies in E. serotinus were 17.58%, 15.15%, 22.22%, 52.73% against R. tsutsugamushi, R. typhi, R. sibirica and R. thai tick typhus, respectively. The high positive rate of antibody related to the high content of Arthropoda. 5. The Positive rate of hantaan virus IFA antibodies were 3.4% (27 of 802) and hanntan virus infection rate 36.7% (22 of 60) by RT-PCR in bats. According these result, we showed that certain species of Athropoda isolated play a role as vector of Rickettsia in E. serotinus. Also bats play a role as a reservoir of hantaan virus in nature.