Using environmental factors to predict Rhipicephalus sanguineus s.l. (Acari: Ixodidae) mortality

Background

Rhipicephalus sanguineus s.l. (Latreille, 1806) can establish indoor populations, which increases the risk of pathogen transmission to humans and companion dogs. Rhipicephalus sanguineus s.l. ticks spend most of their life cycle off the host, which subjects developmental timescale to abiotic factors. Previous studies showed that both temperature and relative humidity (RH) influenced Rhipicephalus sanguineus s.l. survival time across all life stages. However, quantified relationships between environmental factors and Rhipicephalus sanguineus s.l. mortality is not currently available. Here, three Rhipicephalus sanguineus s.l. strains were evaluated for mortality under 20 combinations of five temperatures and four RHs. The data obtained were analyzed to quantify the relationship between environmental factors and Rhipicephalus sanguineus s.l. survival.

Results

Mortality probabilities did not show a consistent pattern between the three tick strains. Temperature, RH, and their interaction influenced Rhipicephalus sanguineus s.l. mortality probabilities across all life stages, with mortality probability generally increasing with temperature but decreasing with RH. With 50% and lower RH, larvae cannot survive for more than 1 week. However, mortality probabilities in all strains and stages were more sensitive to temperature than to RH.

Conclusion

This study identified the predictive relationship between environmental factors and Rhipicephalus sanguineus s.l. survival, which enables estimations of tick survival time under varied residential situations, allows parameterization of population models, and provides guidance for pest control professionals to develop efficient management strategies. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Search and identification methods that owners use to find a lost dog

OBJECTIVE: To characterize the process by which owners search for lost dogs and identify factors associated with time to recovery. DESIGN: Cross-sectional study. SAMPLE POPULATION: Owners of 187 dogs lost in Montgomery County, Ohio, between June 1 and September 30, 2005. PROCEDURES: A telephone survey was conducted. RESULTS: 132 of the 187 (71%) dogs were recovered; median time to recovery was 2 days (range, 0.5 to 21 days). Dogs were recovered primarily through a call or visit to an animal agency (46 [34.8%]), a dog license tag (24 [18.2%]), and posting of neighborhood signs (20 [15.2%]). Eighty-nine (48%) dogs had some type of identification at the time they were lost (ie, identification tag, dog license tag, rabies tag, or microchip). Owners had a higher likelihood of recovery when they called an animal agency (hazard ratio, 2.1), visited an animal agency (1.8), and posted neighborhood signs. Dogs that were wearing a dog license tag also had a higher likelihood of recovery (hazard ratio, 1.6). Owners were less likely to recover their dogs if they believed their dogs were stolen (hazard ratio, 0.3). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that various factors are associated with the likelihood that owners will recover a lost dog. Both animal agencies and veterinarians can play a role in educating dog owners on the importance of identification tags, licensing, and microchips and can help to emphasize the importance of having a search plan in case a dog is lost.     

Insights on endemism: comparison of the duration of the marine larval phase estimated by otolith microstructural analysis of three amphidromous Sicyopterus species (Gobioidei: Sicydiinae) from Vanuatu and New Caledonia

Lord C, Brun C, Hautecœur M, Keith P. Insights on endemism: comparison of the duration of the marine larval phase estimated by otolith microstructural analysis of three amphidromous Sicyopterus species (Gobioidei: Sicydiinae) from Vanuatu and New Caledonia.
Ecology of Freshwater Fish 2010: 19: 26–38. © 2009 John Wiley & Sons A/S
Abstract –  The microstructure of otoliths of three amphidromous gobies (Sicydiinae) of the genus Sicyopterus has been analysed. One of these species, Sicyopterus lagocephalus has a widespread distribution whereas the other two are endemic ( Sicyopterus aiensis , from Vanuatu and Sicyopterus sarasini , from New Caledonia). The microstructural analysis of the otoliths showed that the duration of the marine larval phase is significantly shorter for both endemic species than for the cosmopolitan species (131 ± 3.4 days for S. lagocephalus , 79.2 ± 4.6 days for S. aiensis and 76.5 ± 3.9 days for S. sarasini ). These results led us to infer that it could be one of the factors explaining endemism. We have also improved our knowledge on the processes undergone during the marine phase by studying the growth of the otolith. This work allowed us to propose possible migration routes. These species' reproduction period has also been studied by back-calculating hatching dates. All these elements improve our understanding of the life-history traits and dispersion strategies of these species, which is crucial to implementing conservation measures in order to protect them and their environment, both threatened by anthropogenic actions.     

Predicting nitrogen availability and losses following application of organic manures to arable land: MANNER

Abstract. A decision support system to predict the plant availability of nitrogen (N) following organic manure applications to land has been developed, drawing together the latest UK research information on factors affecting manure N availability and losses. The ADAS MAN ure N itrogen E valuation R outine (MANNER) accounts for manure N analysis, ammonia volatilization, nitrate leaching and mineralization of manure organic N. Only a few easily available inputs are required to predict the amount of N volatilized or leached, and the fertilizer N value for the next crop grown. Predictions from MANNER have been evaluated by comparison with independently collected data from a range of experimental studies where pig, cattle and poultry manures were applied to arable crops. Good agreement was found ( r ² 60–79%, P <0.001), confirming that MANNER can provide a reliable estimate of the fertilizer N value of farm manures spread to arable land under a range of conditions.     

Agricultural nitrogen balance and water quality in the UK

Abstract. Nutrient balance calculations have been advocated as indicators of the risk of nitrate loss from agricultural land. To explore this concept, a spatially distributed UK agricultural nitrogen balance was derived using annually updated statistics. The mean UK N surplus for 1995 was 115 kg N ha^–1, made up of 51 kg ha^–1for arable land, 140 kg ha^–1 for agricultural grassland (excluding rough grazing) and an additional 14 kg N ha^–1for agricultural land from pig and poultry units. Nitrogen surpluses were greater in lowland grassland (mainly in western, wetter areas) than in arable areas. However nitrate concentrations in rivers were generally greater in arable areas. The relationship between N balance and nitrate leaching was very different for grassland and arable systems, and was also sensitive to climate, level of inputs and management practices. Nitrogen surplus was therefore weakly or even negatively correlated with river nitrate concentrations or loads. A positive correlation was found only where the comparison was restricted to grassland-dominated catchments. Nitrogen surplus calculations identified areas of very high livestock densities, which would be associated with increased risk of pollution. However their use in isolation as indicators of N leaching, or of progress towards mitigation, could be misleading especially if comparing areas differing in land use, climate or soil type.     

EFFECTS OF HYDRATION ON SCINTIGRAPHIC GLOMERULAR FILTRATION RATE MEASURED USING INTEGRAL AND PLASMA VOLUME METHODS IN DOGS WITH SUSPECTED RENAL DISEASE

The current standard scintigraphic method for estimating glomerular filtration rate (GFR) in dogs is the integral method, which normalizes renal GFR to body weight. The plasma volume method, that is normalizing GFR to plasma volume, has been reported to be more physiologically correct. The aim of this prospective study was to test the effect of hydration status on GFR measured by these two methods in a group of dogs with suspected renal disease. Eleven dogs were recruited. All dogs underwent standardized scintigraphic examinations before and after 15 ml/kg of fluid was administered intravenously at 5–7 ml/kg/min. Individual kidney GFR estimates (n = 22) were calculated using both methods and a consensus of two observers who were unaware of clinical findings. Individual kidney GFR increased significantly (P = 0.0008) after fluid administration using the integral method and individual kidney GFR using the plasma volume method remained constant. Percentage differences for individual kidney GFR before and after fluid administration were 31.4 ± 58.1% (change ± 95% CI) for the integral method and 0.1 ± 70% (change ± 95% CI) for the plasma volume method. Intravenously administered fluid increased individual kidney GFR from low to normal in 10 of 22 kidneys using the integral method and in 1 of 22 kidneys using the plasma volume method. Findings supported the use of the plasma volume method for scintigraphic calculation of GFR in dogs with suspected renal disease and indicated that errors of kidney status classification may more likely occur when the integral method is used.     

Genome of the host-cell transforming parasite Theileria annulata compared with T. parva

Theileria annulata and T. parva are closely related protozoan parasites that cause lymphoproliferative diseases of cattle. We sequenced the genome of T. annulata and compared it with that of T. parva to understand the mechanisms underlying transformation and tropism. Despite high conservation of gene sequences and synteny, the analysis reveals unequally expanded gene families and species-specific genes. We also identify divergent families of putative secreted polypeptides that may reduce immune recognition, candidate regulators of host-cell transformation, and a Theileria-specific protein domain [frequently associated in Theileria (FAINT)] present in a large number of secreted proteins.     

Congestive heart failure in two pet rabbits

This case report describes congestive heart failure with pleural effusion in two middle-aged, pet house rabbits. Both had a history of acute onset dyspnoea, weakness and weight loss. Bi-atrial enlargement was seen on echocardiography in both rabbits. One rabbit had atrial fibrillation and ventricular premature complexes identified on electrocardiography. There was a radiographically evident pleural effusion in both rabbits and thoracocentesis was undertaken in one rabbit. These findings were confirmed on post-mortem examination. The aetiology for the underlying heart disease was not found, but the potential types of cardiomyopathies are discussed.