The application of moxidectin formulations for control of the cattle tick (Boophilus microplus) under Queensland field conditions

Objective To assess the control of the cattle tick (Boophilus microplus) and the performance of commercial cattle treated with the macrocylic lactone endectocide, moxidectin, formulated either as an injection or as a pour-on. Design Groups of 10–12 tick infested cattle were treated with moxidectin injection, moxidectin pour-on or remained untreated (28-day trials) or were treated with deltamethrinethion as a dip (140-day trials). The cattle were exposed to natural tick challenge under field conditions. Procedure Tick numbers on trial cattle were recorded in each trial before the initial treatment and in the 28-day trials at 7, 14, 21 and 28 days or in the 140-day trials, at 28-day intervals before each of the treatments and at the final inspection. Body weights of the cattle were also recorded prior to the initial treatment and at the termination of each trial. Cattle were observed on the day of each treatment and at each inspection for evidence of any reactions to treatment. Results 28-day trials: Significant reductions in tick counts were recorded in both treatment groups when compared with cattle in the untreated group. Weight advantage was recorded in the moxidectin treated groups. 140-day trials: All three treatments resulted in zero or low tick counts at each inspection with the exception of the pour-on treatment at week 8 in one trial and week 9 in the other trial. Additional weight gain was recorded for both the moxidectin treated groups, relative to the deltamethrin-ethion dip groups, but was significant only for the pour-on groups. There was no evidence of any local or systemic adverse reaction in any treated cattle in any trial. Conclusion Good to excellent control of the cattle tick (Boophilus microplus) was demonstrated with the moxidectin formulations in all trials, the injection being particularly effective. An improved performance was recorded in all trials in cattle treated with both moxidectin formulations when compared with the untreated cattle and with cattle treated with the deltamethrin-ethion dip. There was no evidence of any local or systemic adverse reaction to treatment with either moxidectin formulation.     

寄生于中国水牛Bubalus Vbubalis的巴贝斯虫一新种(梨形虫目:巴贝斯科)

经作者等深入研究，发现湖北省水牛巴贝斯虫病病原不是牛巴贝斯虫Ｂａｂｅｓｉａｂｏｖｉｓ与双芽巴贝斯虫Ｂ．ｂｉｇｅｍｉｎａ，而是一新种——东方巴贝斯虫Ｂａｂｅｓｉａｏｒｉｅｎｔａｌｉｓｓｐ．ｎｏｖ．。病牛红细胞中的虫体呈梨形（单梨形多于双梨形）、椭圆形、指环形、边虫形及杆状。以梨形虫体居多，病的初期其长度均小于红细胞半径，其平均大小为２．２×１．３μｍ，双梨形虫体尖端相连多排列成钝角或一字形，位于红细胞偏中央处。病的后期（出现虫血症后５～６ｄ）及体外培养７２ｈ，有少部份（１～２％）虫体直径大于红细胞半径。新种的传播者为镰形扇头蜱Ｒｈｉｐｉｃｅｐｈａｌｕｓｈａｅｍａｐｈｙｓａｌｏｉｄｅｓｈａｅｍａｐｈｙｓａｌｏｉｄｅｓ经卵传递（由第二代成蜱传给健康牛）。在成蜱的血淋巴中的虫样体（裂殖子）呈圆锥状、一端钝圆、尾部直而尖，不形成钩。新种对黄牛不能感染致病，只能使水牛致病。以１９９培养基加黄牛血清进行体外培养（微气静相培养技术）不能生长繁殖     

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

OBJECTIVE: To describe the actual and potential geographic distributions of Ixodes cornuatus and I holocyclus in south-eastern Australia. PROCEDURE: Examination of ticks from museum collections and trapped animals were made. (Bioclimatic analysis BIOCLIM) was used to predict potential distributions. RESULTS: 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. CONCLUSIONS: 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.     

Identification of the etiologic agent of epizootic bovine abortion in field-collected Ornithodoros coriaceus Koch ticks

Epizootic bovine abortion (EBA), or foothill abortion as it has often been termed, is a tick-borne disease of pregnant cattle recognized in California, Nevada and Oregon. The primary objective of this study was to better define the relationship of a novel deltaproteobacterium, the putative etiological agent of EBA (aoEBA), with the Pajaroello tick (Ornithodoros coriaceus Koch), the recognized vector of EBA. Three developmental stages of O. coriaceus (larva, nymph, and adult) were collected from five locations in California, Nevada and Oregon. A polymerase chain reaction (PCR), developed for detection of aoEBA, was applied to DNA extracted from ticks. Southern blotting of the PCR products increased the number of ticks determined to be carrying the bacteria by seven-fold, suggesting the majority of infected ticks carry relatively low numbers of the pathogen. An effort was made to determine if an artificial blood meal would stimulate replication of the bacterial pathogen, thereby increasing the frequency in which aoEBA could be identified; no statistically significant effect was evident. The number of ticks determined to be carrying aoEBA varied with geographic location and ranged from 5 to 20%. aoEBA was found in both adults (12% of the males and 12% of the females) and nymphs (13%) but not larvae. Comparative analysis of dissected ticks provided strong evidence that the salivary gland was the most common location of aoEBA in field-collected ticks. No significant correlations were identified between the frequency of infection and tick weight, suggesting that increasing tick age and increased number of blood meals did not increase infectivity.     

Tick Bite Prophylaxis: Results From a 2012 Survey of Healthcare Providers

In a recent national survey, over 30% of healthcare providers (HCPs) reported prescribing tick bite prophylaxis in the previous year. To clarify provider practices, we surveyed HCPs to determine how frequently and for what reasons they prescribed tick bite prophylaxis. We included four questions regarding tick bite prophylaxis in the DocStyles 2012 survey, a computer‐administered questionnaire of 2205 US primary care physicians, paediatricians and nurse practitioners. Responses in 14 states with high Lyme disease incidence (high LDI) were compared with responses from other states (low LDI). Overall, 56.4% of 1485 providers reported prescribing tick bite prophylaxis at least once in the previous year, including 73.9% of HCPs in high LDI and 48.2% in low LDI states. The reasons given were ‘to prevent Lyme disease’ (76.9%), ‘patients request it’ (40.4%) and ‘to prevent other tickborne diseases’ (29.4%). Among HCPs who provided prophylaxis, 45.2% did so despite feeling that it was not indicated. Given a hypothetical scenario involving a patient with an attached tick, 38.1% of HCPs from high LDI states and 15.1% from low LDI states would prescribe a single dose of doxycycline; 19.0% from high LDI states and 27.5% from low LDI states would prescribe a full course of doxycycline. HCPs prescribe tick bite prophylaxis frequently in areas where Lyme disease is rare and for tickborne diseases for which it has not been shown effective. HCPs may be unaware of current tick bite prophylaxis guidelines or find them difficult to implement. More information is needed regarding the efficacy of tick bite prophylaxis for diseases other than Lyme disease.     

Babesia canis vogeli,Ehrlichia canis,and Anaplasma platys infection in a dog

A 12‐month‐old male neutered mixed breed dog was presented with a history of diarrhea, lethargy, emaciation, polydypsia, and sniffling. Physical examination findings included pale mucous membranes, increased heart and respiratory rates, and normal rectal temperature (38°C). Hematologic abnormalities included anemia and thrombocytopenia. Biochemical abnormalities included hypoalbuminemia, hyperbilirubinemia, and elevated ALP and ALT activities. A SNAP 4Dx test result was positive for Ehrlichia canis. Babesia canis vogeli organisms were found in the peripheral blood films, while morulae of E canis were not seen. Real‐time polymerase chain reaction testing confirmed the presence of both B c vogeli and E canis organisms, and also was positive for Anaplasma platys infection. The dog recovered following treatment with doxycycline and imidocarb dipropionate, with normal hematology and biochemical profiles.     

Tick infestation and spotted-fever group Rickettsia in shelter dogs, California, 2009

In response to an outbreak of Rocky Mountain spotted fever (RMSF) in Baja California in early 2009, dogs at two shelters in neighbouring Imperial County, California, were evaluated for ectoparasites. Brown dog ticks (Rhipicephalus sanguineus), a recognized vector for RMSF, were found on 35 (30%) of 116 dogs but all ticks tested negative for Rickettsia rickettsii by PCR.     

COMPARISON BETWEEN PROTON MAGNETIC RESONANCE SPECTROSCOPY FINDINGS IN DOGS WITH TICK‐BORNE ENCEPHALITIS AND CLINICALLY NORMAL DOGS

In vivo diagnosis of tick‐borne encephalitis is difficult due to high seroprevalence and rapid viral clearance, limiting detection of antibodies in blood and cerebrospinal fluid. Magnetic resonance imaging (MRI) characteristics of tick‐borne encephalitis have been reported, however MRI studies can also be negative despite the presence of neurologic signs. Magnetic resonance spectroscopy (¹H MRS) is an imaging method that provides additional information about the metabolic characteristics of brain tissues. The purpose of this retrospective cross‐sectional study was to describe brain metabolites using short echo time single‐voxel ¹H MRS in dogs with confirmed tick‐borne encephalitis and compare them with healthy dogs. Inclusion criteria for the affected dogs were neurological symptoms suggestive of tick‐borne encephalitis, previous endemic stay and tick‐bite, diagnostic quality brain MRI and ¹H MRS studies, and positive antibody titers or confirmation of tick‐borne encephalitis with necropsy. Control dogs were 10, clinically normal beagles that had been used in a previous study. A total of six affected dogs met inclusion criteria. All dogs affected with tick‐borne encephalitis had ¹H MRS metabolite concentration alterations versus control dogs. These changes included mild to moderate decreases in N‐acetyl aspartate and creatine peaks, and mild increases in glutamate/glutamine peaks. No lactate or lipid signal was detected in any dog. Myoinositol and choline signals did not differ between affected and control dogs. In conclusion, findings supported the use of ¹H MRS as an adjunctive imaging method for dogs with suspected tick‐borne encephalitis and inconclusive conventional MRI findings.     

Epizootiologic background of dissimilar distribution of human cases of Lyme borreliosis and tick-borne encephalitis in a joint endemic area

Lyme borreliosis (LB) and tick-borne encephalitis (TBE) are co-endemic in some parts of Europe, however, their distribution differs despite a common tick vector and comparable animal hosts. A serosurvey of game and small mammals was made in a highly endemic area and compared with historical data in human cases; the epidemiologic risk and the population density of game were modelled using a geographic information system. While LB-risk corresponded with an overall population density of game (red deer, roe deer, mouflon, wild boar) regardless of mouse abundance, TBE-risk suggested a dependence on the abundance of mice on the one hand, and game, particularly roe deer, on the other. While the prevalence of TBE-antibodies generally grew with the game’s age, it was virtually constant at about 65% in LB irrespective of species. It implies a cumulation of scarce TBE-infection histories during the game’s lifetime, and thus a limited size of TBE-foci relative to the living space of these animals, as well as omnipresent LB-foci, in which the animals became continuously re-infected. More ecological prerequisites seem necessary to keep TBE circulating in nature which may be responsible for its confined distribution.